@inproceedings {INPROC-2021-01,
author = {David Hellmanns and Lucas Haug and Moritz Hildebrand and Frank D{\"u}rr and Stephan Kehrer and Ren{\'e} Hummen},
title = {{How to Optimize Joint Routing and Scheduling Models for TSN Using Integer Linear Programming}},
booktitle = {Proceedings of the 29th International Conference on Real-Time Networks and Systems},
editor = {ACM},
address = {Nantes},
publisher = {ACM (Online)},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--12},
type = {Konferenz-Beitrag},
month = {April},
year = {2021},
isbn = {10.1145/3453417.3453421},
keywords = {Time-Sensitive Networking, TSN, Scheduling, Routing, Integer Linear Programming, Optimization, Model, ILP},
language = {Englisch},
cr-category = {D.4.7 Operating Systems Organization and Design},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2021-01/INPROC-2021-01.pdf},
contact = {david.hellmanns@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Reliable real-time communication is an essential technology for industrial
manufacturing but also other branches to transport mission-critical messages.
IEEE Time-Sensitive Networking (TSN) is a disruptive real-time communication
standard extending IEEE Ethernet with real-time mechanisms. One of the core
features of TSN is the Time-Aware Shaper (TAS) enabling TDMA-based scheduling
of streams within the network. TDMA has many advantages from the real-time
perspective. Foremost, stream isolation in the time dimension enables tight
delay and jitter bounds. Moreover, conformance to these bounds is proven by the
design of the TDMA schedule. However, calculating an optimal schedule is an
NP-hard problem. Therefore, various approaches to optimize the schedule
calculation are proposed, such as Integer Linear Programming (ILP).
Nevertheless, a systematic comparsion of the different optimization approaches
with respect to their performance is missing so far. To fill this gap, we first
provide a systematic classification of optimizations of ILP-based TSN
scheduling. To quantify the effects of such optimization approaches, we
introduce a base ILP and propose optimizations for the different categories.
Using the proposed optimization, we evaluate the performance with regard to
execution time and schedulability (number of solved schedules). Our results
show that the optimizations lead to strongly fluctuating results. Certain
intuitive optimizations can even lead to massive performance degradations.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2021-01&engl=0}
}
@inproceedings {INPROC-2020-28,
author = {Jonathan Falk and Frank D{\"u}rr and Kurt Rothermel},
title = {{Time-Triggered Traffic Planning for Data Networks with Conflict Graphs}},
booktitle = {26th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS 2020)},
address = {Sydney, Australia},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
type = {Konferenz-Beitrag},
month = {April},
year = {2020},
keywords = {Real-Time; Traffic-Planning; Time-Triggered},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2020-28/INPROC-2020-28.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Traffic planning is the key enabler of time-triggered real-time communication
in distributed systems, and it is known to be notoriously hard. Current
approaches predominantly tackle the problem in the domain of the traffic
planning problem, e.g., by formulating constraints on the transmission
schedules for individual data streams, or the links used by the data streams.
This results in a high degree of coupling of the configuration of an individual
data stream and the global (network-wide) traffic configuration with
detrimental effects on the scalability and runtime of the planning phase.
In contrast, we present a configuration-conflict graph based approach, which
solves the original traffic planning problem by searching an independent vertex
set in the conflict graph. We show how to derive the configuration-conflict
graph, and discuss the conceptual advantages of this approach. To show the
practical advantages of the conflict-graph based traffic planning approach we
additionally present a proof-of-concept implementation and evaluate it against
a reference ILP-based implementation. In our evaluations, our proof-of-concept
implementation of the conflict-graph based approach outperforms the reference
ILP and is more memory efficient, making it a promising alternative to current
constraint-based traffic planning approaches.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2020-28&engl=0}
}
@inproceedings {INPROC-2020-05,
author = {Ben William Carabelli and Frank D{\"u}rr and Kurt Rothermel},
title = {{SCRaM -- State-Consistent Replication Management for Networked Control Systems}},
booktitle = {11th IEEE/ACM International Conference on Cyber-Physical Systems (ICCPS)},
address = {Sydney, NSW, Australia},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
type = {Konferenz-Beitrag},
month = {April},
year = {2020},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
C.4 Performance of Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2020-05/INPROC-2020-05.pdf},
contact = {Ben Carabelli ben.carabelli@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Networked control systems (NCS) consist of sensors and actuators that are
connected to a controller through a packet-switched network in a feedback loop
to control physical systems in diverse application areas such as industry,
automotive, or power infrastructure. The control of critical real-time systems
places strong requirements on the latency and reliability of both the
communication network and the controller. In this paper, we consider the
problem of increasing the reliability of an NCS subject to crash failures and
message loss by replicating the controller component. Previous replication
schemes for real-time systems have focused on ensuring that no conflicting
values are sent to the actuators by different replicas. Since this property,
which we call output consistency, only refers to the values within one time
step, it is insufficient for reasoning about the formal conditions under which
a group of replicated controllers behaves equivalent to a non-replicated
controller. Therefore, we propose the stronger state consistency property,
which ensures that the sequence of values produced by the replicated controller
exhibits the same dynamical behaviour as a non-replicated controller. Moreover,
we present SCRaM, a protocol for replicating generic periodically sampled
controllers that satisfies both of these consistency requirements. To
demonstrate the effectiveness of our approach, we evaluated it experimentally
for the control of a cart-driven inverted pendulum.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2020-05&engl=0}
}
@inproceedings {INPROC-2020-02,
author = {David Hellmanns and Jonathan Falk and Alexander Glavackij and Ren{\'e} Hummen and Stephan Kehrer and Frank D{\"u}rr},
title = {{On the Performance of Stream-based, Class-based Time-aware Shaping and Frame Preemption in TSN}},
booktitle = {Proceedings of 2020 IEEE International Conference on Industrial Technology (ICIT), Buenos Aires, Argentinia, February 26–28, 2020},
address = {Buenos Aires},
publisher = {IEEE Xplore},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
pages = {1--6},
type = {Konferenz-Beitrag},
month = {Februar},
year = {2020},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2020-02/INPROC-2020-02.pdf},
contact = {david.hellmanns@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
abstract = {Time-sensitive Networking (TSN) is an evolving group of IEEE standards for
deterministic real-time communication making standard Ethernet technology
applicable to safety-critical application domains such as manufacturing or
automotive systems. TSN includes several mechanisms influencing the timely
forwarding of traffic, in particular, a time-triggered scheduling mechanism
called time-aware shaper (TAS) and frame preemption to reduce the blocking time
of high-priority traffic by low-priority traffic. Although these mechanisms
have been standardized and products implementing them begin to enter the
market, it is still hard for practitioners to select and apply suitable
mechanisms fitting the problem at hand. For instance, TAS schedules can be
calculated for individual streams or classes of traffic, and frame preemption
with strict priority scheduling (w/o TAS) might seem to be an option in
networks with extremely high data rates. In this paper, we make a first step
towards assisting practitioners in making an informed decision when choosing
between stream-based TAS, class-based TAS, and frame preemption by comparing
these mechanisms in selected scenarios using our TSN network simulation tool
NeSTiNg. Moreover, to facilitate the application of class-based TAS, we derive
a formula for calculating class-based TAS configuration.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2020-02&engl=0}
}
@inproceedings {INPROC-2019-45,
author = {Otto Bibartiu and Frank D{\"u}rr and Kurt Rothermel and Beate Ottenw{\"a}lder and Andreas Grau},
title = {{Towards Scalable k-out-of-n Models for Assessing the Reliability of Large-scale Function-as-a-Service Systems with Bayesian Networks}},
booktitle = {2019 IEEE 12th International Conference on Cloud Computing (CLOUD)},
editor = {IEEE},
address = {Milan, Italy},
publisher = {Online},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--3},
type = {Konferenz-Beitrag},
month = {Juli},
year = {2019},
isbn = {10.1109/CLOUD.2019.00095},
keywords = {Bayesian networks, k-out-of-n gates, scalable structures},
language = {Englisch},
cr-category = {B.8.1 Reliability, Testing, and Fault-Tolerance},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2019-45/INPROC-2019-45.pdf,
https://ieeexplore.ieee.org/document/8814557/},
contact = {otto.bibartiu@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Typically, Function-as-a-Service (FaaS) involves state-less replication with
very large numbers of instances. The reliability of such services can be
evaluated using Bayesian Networks and k-out-of-n models. However, existing
k-out-of-n models do not scale to the larger number of hosts of FaaS services.
Therefore, we propose a scalable k-out-of-n model in this paper with the same
semantics as the standard k-out-of-n voting gates in fault trees, enabling the
reliability analysis of FaaS services.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2019-45&engl=0}
}
@inproceedings {INPROC-2019-23,
author = {Jonathan Falk and Frank D{\"u}rr and Steffen Linsenmayer and Stefan Wildhagen and Carabelli Ben and Kurt Rothermel},
title = {{Optimal Routing and Scheduling of Complemental Flows in Converged Networks}},
booktitle = {Proceedings of the 27th International Conference on Real-Time Networks and Systems (RTNS 2019), November 6-8, 2019 -Toulouse/France},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
type = {Konferenz-Beitrag},
month = {November},
year = {2019},
doi = {10.1145/3356401.3356415},
keywords = {Routing Scheduling Complemental Flows},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2019-23/INPROC-2019-23.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Converged networks support applications with completely different (real-time)
requirements. The communication paradigms offered in converged networks are
predominantly treated as separate entities from the perspective of traffic
engineering, e.g., time-triggered traffic for closed-loop control systems,
shaped traffic for multimedia-streaming applications, and best-effort traffic
for non-time-critical IT applications. However, there are scenarios where
applications benefit from considering time-triggered messages and
non-time-triggered messages as complemental components of a single traffic
flow. These applications have the property that time-triggered transmissions
guarantee basic functionality (e.g., stability of a control system), and
additional non-time-triggered transmissions improve the application's
performance.
We present how to model these so-called complemental traffic flows for this
type of application using a traffic metric for the description of the
non-time-triggered traffic part. Furthermore, we show that complemental flows
are suitable for traffic engineering by presenting two different approaches for
the problem of optimized joint routing and scheduling in converged networks
with mixed integer linear programming.
In our evaluations, we use an exemplary min-max objective for the joint routing
and scheduling problem which yields an average reduction of the peak value of
the traffic metric by 20-30$\backslash$\% over constraint-based approaches.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2019-23&engl=0}
}
@inproceedings {INPROC-2019-22,
author = {Jonathan Falk and Frank D{\"u}rr and Kurt Rothermel},
title = {{Modeling Time-Triggered Service Intermittence In Network Calculus}},
booktitle = {Proceedings of the 27th International Conference on Real-Time Networks and Systems (RTNS 2019), November 6-8, 2019 -Toulouse/France},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
type = {Konferenz-Beitrag},
month = {November},
year = {2019},
doi = {10.1145/3356401.3356411},
keywords = {Real-time, Network Calculus Service Intermittence},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2019-22/INPROC-2019-22.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Network elements (e.g., switches), which intermit service, i.e., stop
forwarding and transmission of data according to a repeating schedule, can be
found in many real-time capable communication networks, e.g., communication
networks with TDMA, Ethernet with Time-aware Shapers or low-power wireless
networks. The behavior of those network elements depends on the (stationary)
properties of the network elements, their schedule, and the current time, as
well as the offered traffic load. If a networked real-time system generates
traffic flows which are not synchronized to the schedules of the network
elements, formal frameworks such as Network Calculus (NC) are highly valuable
to derive deterministic guarantees for the communication.
In this paper, we show the fundamental implications of modeling time-triggered
network elements with service intermittence in NC. We identify two archetypes
of network elements with intermittent service, and propose time-variant and
time-invariant approaches to derive service curve formulations to model them.
We evaluate the differences between time-variant and time-invariant service
curves with respect to the overestimation of worst-case backlog and worst-case
delay, and we identify schedule properties which influence the tightness of the
derived bounds.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2019-22&engl=0}
}
@inproceedings {INPROC-2019-04,
author = {Jonathan Falk and David Hellmanns and Ben Carabelli and Naresh Nayak and Frank D{\"u}rr and Stephan Kehrer and Kurt Rothermel},
title = {{NeSTiNg: Simulating IEEE Time-sensitive Networking (TSN) in OMNeT++}},
booktitle = {Proceedings of the 2019 International Conference on Networked Systems (NetSys)},
address = {Garching b. M{\"u}nchen, Germany},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2019},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2019-04/INPROC-2019-04.pdf,
https://gitlab.com/ipvs/nesting},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {IEEE 802.1 Time-sensitive Networking (TSN) enables real-time communication with
deterministically bounded network delay and jitter over standard IEEE 802.3
networks (``Ethernet''). In particular, TSN specifies a time-triggered scheduling
mechanism in IEEE Std 802.1Qbv implemented by switches to control when outgoing
queues get access to switch ports. Besides this time-triggered scheduling
mechanism, other scheduling mechanisms can be active in the network at the same
time including priority queuing and a credit-based shaper. Moreover, further
supporting mechanisms such as the possibility to interrupt frames already in
transmission (frame preemption) are specified by the TSN standards. Overall,
this leads to a complex network infrastructure transporting both, real-time and
non-real-time traffic in one converged network, making it hard to analyze the
behavior of converged networks.
To facilitate the analysis of TSN networks, we present TSN-specific extensions
to the popular OMNeT++/INET framework for network simulations in this paper
including, in particular, the time-triggered scheduling mechanism of IEEE Std
802.1Qbv. Besides the design of the TSN simulator, we present a
proof-of-concept implementation and exemplary evaluation of TSN networks.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2019-04&engl=0}
}
@inproceedings {INPROC-2019-01,
author = {Steffen Linsenmayer and Ben W. Carabelli and Frank D{\"u}rr and Jonathan Falk and Frank Allg{\"o}wer and Kurt Rothermel},
title = {{Integration of Communication Networks and Control Systems Using a Slotted Transmission Classification Model}},
booktitle = {Proceedings of the 16th IEEE Annual Consumer Communications \& Networking Conference (CCNC)},
address = {Las Vegas, NV, USA},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
type = {Workshop-Beitrag},
month = {Januar},
year = {2019},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2019-01/INPROC-2019-01.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In this paper, we present a communication abstraction for Networked Control
Systems that is characterized by a slotted transmission classification model.
We discuss, how such a model can be implemented over local area networks by
using IEEE Time Sensitive Networking methods. Furthermore, it is shown how
asymptotic stability can be analyzed for linear systems that communicate over
such a network. Based on the stability result, a controller design procedure is
derived that takes the information captured in the network model into account.
Further topics and related open problems that are implicated by the proposed
model are briefly discussed as an outlook.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2019-01&engl=0}
}
@inproceedings {INPROC-2018-46,
author = {Jonathan Falk and Frank D{\"u}rr and Kurt Rothermel},
title = {{Exploring Practical Limitations of Joint Routing and Scheduling for TSN with ILP}},
booktitle = {Proceedings of the 2018 IEEE 24th International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2018) Hakodate, Japan, 29-31 August 2018},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {136--146},
type = {Konferenz-Beitrag},
month = {August},
year = {2018},
doi = {10.1109/RTCSA.2018.00025},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2018-46/INPROC-2018-46.pdf,
https://ieeexplore.ieee.org/document/8607243},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {IEEE 802.1Q networks with extensions for time-sensitive networking aim to
enable converged networks. Converged networks support hard-real time
communication services in addition to the currently supported services classes.
Real-time communication in these networks requires routes and schedules for the
real-time transmissions. We present a formulation in the integer linear
programming (ILP) framework which models the joint routing and scheduling
problem for flows of periodic real-time transmissions in converged TSN
networks. In the joint routing and scheduling problem, both routes and
schedules for real-time transmissions are computed in one step, i.e. we do not
schedule over predefined routes. We explore the practical limitations of this
approach by evaluating the runtime of problem instances with widely varying
parameters with a state-of-the-art ILP solver. The observed solver runtimes
indicate the qualitative impact of the number of real-time flows, the size of
the network, the transmission frequency of real-time transmissions, and the
network topology.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2018-46&engl=0}
}
@inproceedings {INPROC-2018-26,
author = {Zohaib Riaz and Frank D{\"u}rr and Kurt Rothermel},
title = {{Location Privacy and Utility in Geo-social: Survey and Research Challenges}},
booktitle = {Proceedings of the 16th Annual Conference on Privacy, Security and Trust (PST 2018), August 28-30, 2018, Belfast, Northern Ireland, United Kingdom.},
publisher = {IEEE Xplore},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {August},
year = {2018},
language = {Englisch},
cr-category = {K.4 Computers and Society},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2018-26/INPROC-2018-26.pdf},
contact = {zohaib.riaz@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2018-26&engl=0}
}
@inproceedings {INPROC-2018-21,
author = {Saravana Murthy Palanisamy and Frank D{\"u}rr and Muhammad Adnan Tariq and Kurt Rothermel},
title = {{Preserving Privacy and Quality of Service in Complex Event Processing through Event Reordering}},
booktitle = {Conference Proceedings: Proceedings of the 12th ACM International Conference on Distributed and Event-Based Systems: DEBS2018 ; Hamilton, New Zealand, June 25-29, 2018},
address = {Hamilton, New Zealand},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
series = {Saravana Murthy Palanisamy},
pages = {40--51},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2018},
isbn = {978-1-4503-5782-1},
language = {Englisch},
cr-category = {D.4.6 Operating Systems Security and Protection,
G.1.6 Numerical Analysis Optimization,
F.1.1 Models of Computation},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2018-21/INPROC-2018-21.pdf,
https://doi.org/10.1145/3210284.3210296},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2018-21&engl=0}
}
@inproceedings {INPROC-2018-16,
author = {Thomas Kohler and Ruben Mayer and Frank D{\"u}rr and Marius Maa{\ss} and Sukanya Bhowmik and Kurt Rothermel},
title = {{P4CEP: Towards In-Network Complex Event Processing}},
booktitle = {Proceedings of the ACM SIGCOMM 2018 Morning Workshop on In-Network Computing},
address = {Budapest, Hungary},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
series = {NetCompute'18},
pages = {0--5},
type = {Konferenz-Beitrag},
month = {August},
year = {2018},
doi = {10.1145/3229591.3229593},
isbn = {978-1-4503-5908-5/18/08},
keywords = {In-network Computing, Data Plane Programming, P4, Complex Event Processing (CEP)},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.4 Distributed Systems,
C.2.3 Network Operations},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2018-16/INPROC-2018-16.pdf,
https://doi.org/10.1145/3229591.3229593},
contact = {thomas.kohler@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In-network computing using programmable networking hardware is a strong trend
in networking that promises to reduce latency and consumption of server
resources through offloading to network elements (programmable switches and
smart NICs). In particular, the data plane programming language P4 together
with powerful P4 networking hardware has spawned projects offloading services
into the network, e.g., consensus services or caching services. In this paper,
we present a novel case for in-network computing, namely, Complex Event
Processing (CEP). CEP processes streams of basic events, e.g., stemming from
networked sensors, into meaningful complex events. Traditionally, CEP
processing has been performed on servers or overlay networks. However, we argue
in this paper that CEP is a good candidate for in-network computing along the
communication path avoiding detouring streams to distant servers to minimize
communication latency while also exploiting processing capabilities of novel
networking hardware. We show that it is feasible to express CEP operations in
P4 and also present a tool to compile CEP operations, formulated in our P4CEP
rule specification language, to P4 code. Moreover, we identify challenges and
problems that we have encountered to show future research directions for
implementing full-fledged in-network CEP systems.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2018-16&engl=0}
}
@inproceedings {INPROC-2018-15,
author = {Christoph Stach and Sascha Alpers and Stefanie Betz and Frank D{\"u}rr and Andreas Fritsch and Kai Mindermann and Saravana Murthy Palanisamy and Gunther Schiefer and Manuela Wagner and Bernhard Mitschang and Andreas Oberweis and Stefan Wagner},
title = {{The AVARE PATRON: A Holistic Privacy Approach for the Internet of Things}},
booktitle = {Proceedings of the 15th International Conference on Security and Cryptography (SECRYPT '18)},
publisher = {INSTICC Press},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--8},
type = {Konferenz-Beitrag},
month = {Juli},
year = {2018},
keywords = {Privacy; IoT Apps; Smart Things; Stream Processing; Privacy Preferences Elicitation \& Veri\&\#64257; cation},
language = {Englisch},
cr-category = {K.4.1 Computers and Society Public Policy Issues,
D.4.6 Operating Systems Security and Protection},
contact = {Senden Sie eine E-Mail an Christoph.Stach@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware;
Universit{\"a}t Stuttgart, Institut f{\"u}r Softwaretechnologie, Software Engineering;
Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Applications for the Internet of Things are becoming increasingly popular. Due
to the large amount of available context data, such applications can be used
effectively in many domains. By interlinking these data and analyzing them, it
is possible to gather a lot of knowledge about a user. Therefore, these
applications pose a threat to privacy. In this paper, we illustrate this threat
by looking at a real-world application scenario. Current state of the art
focuses on privacy mechanisms either for Smart Things or for big data
processing systems. However, our studies show that for a comprehensive privacy
protection a holistic view on these applications is required. Therefore, we
describe how to combine two promising privacy approaches from both categories,
namely AVARE and PATRON. Evaluation results confirm the thereby achieved
synergy effects.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2018-15&engl=0}
}
@inproceedings {INPROC-2018-04,
author = {Christoph Stach and Frank D{\"u}rr and Kai Mindermann and Saravana Murthy Palanisamy and Stefan Wagner},
title = {{How a Pattern-based Privacy System Contributes to Improve Context Recognition}},
booktitle = {Proceedings of the 2018 IEEE International Conference on Pervasive Computing and Communications Workshops (CoMoRea)},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--6},
type = {Workshop-Beitrag},
month = {M{\"a}rz},
year = {2018},
keywords = {privacy; access control; pattern concealing; stream processing; complex event processing; databases},
language = {Englisch},
cr-category = {K.4.1 Computers and Society Public Policy Issues,
D.4.6 Operating Systems Security and Protection},
contact = {Senden Sie eine E-Mail an Christoph.Stach@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware;
Universit{\"a}t Stuttgart, Institut f{\"u}r Softwaretechnologie, Software Engineering;
Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {As Smart Devices have access to a lot of user-preferential data, they come in
handy in any situation. Although such data - as well as the knowledge which can
be derived from it - is highly beneficial as apps are able to adapt their
services appropriate to the respective context, it also poses a privacy threat.
Thus, a lot of research work is done regarding privacy. Yet, all approaches
obfuscate certain attributes which has a negative impact on context recognition
and thus service quality. Therefore, we introduce a novel access control
mechanism called PATRON. The basic idea is to control access to information
patterns. For instance, a person suffering from diabetes might not want to
reveal his or her unhealthy eating habit, which can be derived from the pattern
``rising blood sugar level'' -$>$ ``adding bread units''. Such a pattern which must
not be discoverable by some parties (e.g., insurance companies) is called
private pattern whereas a pattern which improves an app's service quality is
labeled as public pattern. PATRON employs different techniques to conceal
private patterns and, in case of available alternatives, selects the one with
the least negative impact on service quality, such that the recognition of
public patterns is supported as good as possible.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2018-04&engl=0}
}
@inproceedings {INPROC-2017-55,
author = {Thomas Kohler and Frank D{\"u}rr and Christian B{\"a}umlisberger and Kurt Rothermel},
title = {{InFEP - Lightweight Virtualization of Distributed Control on White-box Networking Hardware}},
booktitle = {2017 International Workshop on Management of SDN and NFV Systems (ManSDNNFV2017)},
editor = {IFIP/IEEE},
address = {Tokyo, Japan},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--6},
type = {Konferenz-Beitrag},
month = {November},
year = {2017},
doi = {10.23919/CNSM.2017.8256045},
keywords = {Software-defined Networking; Control Plane Distribution; Virtualization},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.4 Distributed Systems,
C.2.3 Network Operations},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-55/INPROC-2017-55.pdf,
https://doi.org/10.23919/CNSM.2017.8256045},
contact = {thomas.kohler@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Recent developments in networking hardware and software-defined networking have
enabled full distribution of network control to reduce control latency and
increase reliability. However, both, hardware and software of current white-box
networking hardware are highly heterogeneous, which limits the deployment and
operation of switch-local control applications. Furthermore, switch-local
control raises yet unconsidered security concerns. In this paper, we present
our concept of in-forward-element processing, which leverages the open access
to the control plane of white-box networking hardware to deploy control logic
directly onto switches. We combine local control applications with lightweight
virtualization to cope with networking hardware heterogeneity and to achieve
required isolation properties and ease of management. Beyond distributed
network control, we show this scheme is also beneficial for implementing
switch-local virtual network functions (NFV), processing packets. Highlighting
the practicability of the concepts, we provide an overview of the current
white-box networking hardware and software landscape and their compatibility
with lightweight virtualization technologies. To this end, we perform an
empirical evaluation of NOS-virtualization combinations on such hardware and
compare the results with respect to incurring virtualization overhead.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-55&engl=0}
}
@inproceedings {INPROC-2017-50,
author = {Naresh Ganesh Nayak and Frank D{\"u}rr and Kurt Rothermel},
title = {{Routing Algorithms for IEEE802.1Qbv Networks}},
booktitle = {In the 15th International Workshop on Real-Time Networks, RTN-2017},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--6},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2017},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.3 Network Operations},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-50/INPROC-2017-50.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-50&engl=0}
}
@inproceedings {INPROC-2017-46,
author = {Zohaib Riaz and Frank D{\"u}rr and Kurt Rothermel},
title = {{Understanding Vulnerabilities of Location Privacy Mechanisms against Mobility Prediction Attacks}},
booktitle = {Proceedings of the 14th EAI International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services, Melbourne, VIC, Australia, November 7–10, 2017 (MobiQuitous’17)},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {September},
year = {2017},
isbn = {ACM ISBN: 978-1-4503-5368-7/17/11, DOI:10.1145/3144457.314450544505},
keywords = {location privacy; attack algorithms; semantic location information; mobility prediction; hidden Markov models},
language = {Englisch},
cr-category = {C.2.0 Computer-Communication Networks, General,
D.2 Software Engineering,
K.4.1 Computers and Society Public Policy Issues,
G.3 Probability and Statistics},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-46/INPROC-2017-46.pdf},
contact = {zohaib.riaz@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-46&engl=0}
}
@inproceedings {INPROC-2017-32,
author = {Christoph Stach and Frank D{\"u}rr and Kai Mindermann and Saravana Murthy Palanisamy and Muhammad Adnan Tariq and Bernhard Mitschang and Stefan Wagner},
title = {{PATRON - Datenschutz in Datenstromverarbeitungssystemen}},
booktitle = {Informatik 2017: Digitale Kulturen, Tagungsband der 47. Jahrestagung der Gesellschaft f{\"u}r Informatik e.V. (GI), 25.09. - 29.09.2017, Technische Universit{\"a}t Chemnitz},
publisher = {Gesellschaft f{\"u}r Informatik e.V. (GI)},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
series = {LNI},
pages = {1--12},
type = {Workshop-Beitrag},
month = {September},
year = {2017},
keywords = {Datenschutz; Zugriffskontrolle; Datenstr{\"o}me; Internet der Dinge; Privatheit; Sensoren},
language = {Deutsch},
cr-category = {K.4.1 Computers and Society Public Policy Issues,
D.4.6 Operating Systems Security and Protection},
contact = {Senden Sie eine E-Mail an Christoph.Stach@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware;
Universit{\"a}t Stuttgart, Institut f{\"u}r Softwaretechnologie, Software Engineering;
Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Angetrieben durch die stetig voranschreitende Digitalisierung gewinnt das
Internet der Dinge (engl. IoT) immer mehr an Bedeutung. Im IoT werden
technische Ger{\"a}te mit unterschiedlichen Sensoren ausgestattet und miteinander
vernetzt. Dadurch werden neuartige Anwendungen beispielsweise im Bereich
E-Health erm{\"o}glicht, in denen Sensordaten miteinander kombiniert und so in
h{\"o}herwertige Informationen umgewandelt werden. Die von diesen Anwendungen
abgeleiteten Informationen verraten viel {\"u}ber den Nutzer und m{\"u}ssen daher
besonders gesch{\"u}tzt werden. H{\"a}ufig hat der Nutzer allerdings keine Kontrolle
{\"u}ber die Verarbeitung seiner Daten, ganz davon zu schweigen, dass er das Ausma{\ss}
und die Art der daraus ableitbaren Informationen nicht ermessen kann.
In diesem Artikel stellen wir daher einen neuartigen Kontrollmechanismus vor,
der private Informationen im IoT sch{\"u}tzt. Anstelle von abstrakten
Datenschutzregeln f{\"u}r einzelne Sensoren definiert der Nutzer Muster, die es zu
sch{\"u}tzen gilt. Ein Muster kann beispielsweise eine Kombination aus Messwerten
sein, die auf eine bestimmte Krankheit schlie{\ss}en lassen. Der Nutzer definiert
die zu verheimlichenden Informationen nat{\"u}rlichsprachlich, und ein
Dom{\"a}nenexperte setzt diese in formale Regeln um. Sind diese Regeln zu
restriktiv, so kann die Anwendung ihre angedachte Funktionalit{\"a}t nicht
erbringen. Daher muss bez{\"u}glich der Servicequalit{\"a}t ein Kompromiss zwischen
gew{\"u}nschter Privatheit und ben{\"o}tigter Funktionalit{\"a}t gefunden werden.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-32&engl=0}
}
@inproceedings {INPROC-2017-22,
author = {Thomas Kohler and Frank D{\"u}rr and Kurt Rothermel},
title = {{ZeroSDN: A Highly Flexible and Modular Architecture for Full-range Network Control Distribution}},
booktitle = {Proceedings of the 13th ACM/IEEE Symposium on Architectures for Networking and Communications Systems: ANCS'17, May 18-19, 2017, Beijing, China},
editor = {ACM/IEEE},
publisher = {Association for Computing Machinery (ACM) / Institute of Electrical and Electronics Engineers (IEEE)},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--13},
type = {Konferenz-Beitrag},
month = {Mai},
year = {2017},
keywords = {Software-defined Networking; OpenFlow; Control Plane Distribution; Publish/Subscribe; White-box Networking},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.4 Distributed Systems,
C.2.3 Network Operations},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-22/INPROC-2017-22.pdf},
contact = {thomas.kohler@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-22&engl=0}
}
@inproceedings {INPROC-2017-09,
author = {Ben William Carabelli and Rainer Blind and Frank D{\"u}rr and Kurt Rothermel},
title = {{State-dependent Priority Scheduling for Networked Control Systems}},
booktitle = {Proceedings of the 2017 American Control Conference (ACC)},
address = {Seattle, WA, USA},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1003--1010},
type = {Konferenz-Beitrag},
month = {Mai},
year = {2017},
doi = {10.23919/ACC.2017.7963084},
keywords = {cyber-physical systems; networked control systems; optimization; scheduling},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.4 Distributed Systems,
G.1.6 Numerical Analysis Optimization},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-09/INPROC-2017-09.pdf,
http://ieeexplore.ieee.org/document/7963084/,
https://arxiv.org/abs/1703.08311},
contact = {ben.carabelli@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Networked control systems (NCS) have attracted considerable attention in recent
years. While the stabilizability and optimal control of NCS for a given
communication system has already been studied extensively, the design of the
communication system for NCS has recently seen an increase in more thorough
investigation. In this paper, we address an optimal scheduling problem for a
set of NCS sharing a dedicated communication channel, providing performance
bounds and asymptotic stability. We derive a suboptimal scheduling policy with
dynamic state-based priorities calculated at the sensors, which are then used
for stateless priority queuing in the network, making it both scalable and
efficient to implement on routers or multi-layer switches. These properties are
beneficial towards leveraging existing IP networks for control, which will be a
crucial factor for the proliferation of wide-area NCS applications. By allowing
for an arbitrary number of concurrent transmissions, we are able to investigate
the relationship between available bandwidth, transmission rate, and delay. To
demonstrate the feasibility of our approach, we provide a proof-of-concept
implementation of the priority scheduler using real networking hardware.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-09&engl=0}
}
@inproceedings {INPROC-2017-03,
author = {Christoph Dibak and Frank D{\"u}rr and Kurt Rothermel},
title = {{Demo: Server-Assisted Interactive Mobile Simulations for Pervasive Applications}},
booktitle = {Proceedings of the 15th IEEE International Conference on Pervasive Computing and Communications (PerCom Demos)},
address = {Kona, Hawaii, USA},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--3},
type = {Demonstration},
month = {M{\"a}rz},
year = {2017},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
G.1 Numerical Analysis},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-03/INPROC-2017-03.pdf},
contact = {Christoph Dibak christoph.dibak@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Emerging augmented reality devices allow for visualizing results of numerical
simulations ubiquitously. This enables decision makers and engineers in the
field to make better decisions. However, computation of resource-intensive
simulation models on resource-poor and battery-powered mobile devices requires
to drastically reduce the quality of the simulation. We therefore proposed
approaches utilizing a remote server and the Reduced Basis Method (RBM) to
generate a reduced model of the simulation.
In our demo, we demonstrate the effectiveness of our approaches for mobile
simulations. Our demo consists of two devices, a mobile device and a server.
Both devices are connected via wireless network. The mobile device visualizes
the result of a complex computation. Parameters of the simulation are effected
by sensors of the mobile device. The user can choose between computing on the
mobile device, computing solely on the server, or computing using our approach.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-03&engl=0}
}
@inproceedings {INPROC-2017-02,
author = {Christoph Dibak and Andreas Schmidt and Frank D{\"u}rr and Bernard Haasdonk and Kurt Rothermel},
title = {{Server-Assisted Interactive Mobile Simulations for Pervasive Applications}},
booktitle = {Proceedings of the 15th IEEE International Conference on Pervasive Computing and Communications (PerCom)},
address = {Kona, Hawaii, USA},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2017},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
G.1 Numerical Analysis},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-02/INPROC-2017-02.pdf},
contact = {Christoph Dibak christoph.dibak@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Currently, various hardware and software companies are developing augmented
reality devices, most prominently Microsoft with its Hololens. Besides gaming,
such devices can be used for serious pervasive applications, like interactive
mobile simulations to support engineers in the field. Interactive simulations
have high demands on resources, which the mobile device alone is unable to
satisfy. Therefore, we propose a framework to support mobile simulations by
distributing the computation between mobile device and a remote server. For the
computation of parameter-dependent solutions of the simulation, we use the
reduced basis method, which allows to drastically reduce the computation time
and energy consumption. We present three approaches for the distributed
execution of the reduced basis method between mobile device and server.
Evaluations show that we can speed-up the numerical computation to over 131
times while using 73 times less energy compared to offloading everything to a
server.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-02&engl=0}
}
@inproceedings {INPROC-2016-41,
author = {Stephan Schnitzer and Simon Gansel and Frank D{\"u}rr and Kurt Rothermel},
title = {{Real-time scheduling for 3D GPU rendering}},
booktitle = {11th IEEE International Symposium on Industrial Embedded Systems (SIES)},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {Mai},
year = {2016},
doi = {10.1109/SIES.2016.7509411},
keywords = {automobiles; graphical user interfaces; graphics processing units; rendering (computer graphics); 3D GPU rendering; GPU sharing; real-time GPU scheduling framework; real-time scheduling; automotive HMI; embedded systems},
language = {Englisch},
cr-category = {H.5.2 Information Interfaces and Presentation User Interfaces,
I.3.m Computer Graphics Miscellaneous},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-41/INPROC-2016-41.pdf,
http://dx.doi.org/10.1109/SIES.2016.7509411},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {3D graphical functions in cars enjoy growing popularity. For instance, analog
instruments of the instrument cluster are replaced by digital 3D displays as
shown by Mercedes-Benz in the F125 prototype car. The trend to use 3D
applications expands into two directions: towards more safety-relevant
applications such as the speedometer and towards third-party applications,
e.g., from an app store. In order to save cost, energy, and installation space,
all these applications should share a single GPU. GPU sharing brings up the
problem of providing real-time guarantees for rendering content of
time-sensitive applications like the speedometer. To solve this problem, we
present a real-time GPU scheduling framework which provides strong guarantees
for critical applications while still giving as much GPU resources to less
important applications as possible, thus ensuring a high GPU utilization. Since
current GPUs are not preemptible, we use the estimated execution time of each
GPU rendering job to make the scheduling decisions. Our evaluations show that
our scheduler guarantees given real-time constraints, while achieving a high
GPU utilization of 97\%. Moreover, scheduling is performed highly efficient in
real-time with less than 10 us latency.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-41&engl=0}
}
@inproceedings {INPROC-2016-34,
author = {Florian Berg and Frank D{\"u}rr and Kurt Rothermel},
title = {{Increasing the Efficiency of Code Offloading in n-tier Environments with Code Bubbling}},
booktitle = {Proceedings of the 13th Annual International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services},
publisher = {-},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
type = {Konferenz-Beitrag},
month = {November},
year = {2016},
isbn = {978-1-4503-4750-1/16/11},
doi = {dx.doi.org/10.1145/2994374.2994375},
keywords = {Mobile Cloud Computing; Multi-tier Code Offloading; Cyber Foraging; Code Bubbling; n-tier environment},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
contact = {Florian.Berg@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Code offloading strives for increasing the energy efficiency and execution
speed of mobile applications on resource-constrained mobile devices. First
approaches considered only a code offloading between two (or three) tiers,
executing code either locally on the mobile device or remotely on a powerful
server in the vicinity or in a distant cloud. However, new execution
environments comprise multiple tiers, containing highly distributed
heterogeneous resources. We present in this paper our Code Bubbling Offload
System (CoBOS). CoBOS targets n-tier environments containing highly distributed
heterogeneous resources with different performance characteristics and cost
implications. In such n-tier environments, it is very costly for a
resource-constrained mobile device to gather a global view on available
resources. As a result, we propose the novel concept of code bubbling. Code
bubbling moves code dynamically and adaptively towards more powerful and more
distant tiers, enabling an efficient and scalable code offloading in n-tier
environments. Each tier makes autonomous decisions to execute code in the tier
or forward it further to the next tier. To support such a recursive escalation
of code along autonomous tiers, CoBOS offloads self-contained offload requests
that possess all of the required information for the processing. Our real-world
evaluation shows that CoBOS decreases the energy consumption by 77\% and the
execution time by 83\% for code offloading in n-tier environments.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-34&engl=0}
}
@inproceedings {INPROC-2016-32,
author = {Frank D{\"u}rr and Naresh Ganesh Nayak},
title = {{No-wait Packet Scheduling for IEEE Time-sensitive Networks (TSN)}},
booktitle = {24th International Conference on Real-Time Networks and Systems, RTNS-2016},
address = {Brest, France},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2016},
keywords = {Time-sensitive network, TSN, Real-time communication, Job shop scheduling problem, Tabu search, IEEE 802.1Qbv},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.3 Network Operations},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-32/INPROC-2016-32.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {The IEEE Time-sensitive Networking (TSN) Task Group has recently standardized
enhancements for IEEE 802.3 networks for enabling it to transport
time-triggered traffic (aka scheduled traffic) providing them with stringent
bounds on network delay and jitter while also transporting best-effort traffic.
These enhancements primarily include dedicating one queue per port of the
switch for scheduled traffic along with a programmable gating mechanism that
dictates which of the queues are to be considered for transmission. While the
IEEE 802.1Qbv standards define these mechanisms to handle scheduled traffic, it
stops short of specifying algorithms to compute fine-grained link schedules for
the streams of scheduled traffic. Further, the mechanisms in TSN require
creation of so-called guard bands to isolate scheduled traffic from the
best-effort traffic. These guard bands may potentially result in bandwidth
wastage, and hence schedules with lower number of guard bands are preferred. In
this paper, we introduce the No-wait Packet Scheduling Problem (NWPSP) for
modelling the scheduling in IEEE Time-sensitive Networks and map it to the
No-wait Job-shop Scheduling Problem (NW-JSP), a well-known problem from the
field of operational research. In particular, we present a Tabu search
algorithm for efficient computing of schedules and a schedule compression
technique to reduce number of guard bands in schedule. Our evaluations show
that our Tabu search algorithm can compute near-optimal schedules for over 1500
flows and the subsequent schedule compression reduces the number of guard bands
on an average by 24\%.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-32&engl=0}
}
@inproceedings {INPROC-2016-31,
author = {Naresh Ganesh Nayak and Frank D{\"u}rr and Kurt Rothermel},
title = {{Time-sensitive Software-defined Network (TSSDN) for Real-time Applications}},
booktitle = {Proceedings of the 24th International Conference on Real-Time Networks and Systems, RTNS 2016},
address = {Brest, France},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2016},
language = {Deutsch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.3 Network Operations},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-31/INPROC-2016-31.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Cyber-physical systems (CPS), like the ones used in industrial automation
systems, are highly time-sensitive applications demanding zero packet losses
along with stringent real-time guarantees like bounded latency and jitter from
the underlying network for communication. With the proliferation of IEEE 802.3
and IP networks, there is a desire to use these networks instead of the
currently used fieldbuses for time-sensitive applications. However, these
networking technologies, which originally were designed to provide best effort
communication services, lack mechanisms for providing real-time guarantees. In
this paper, we present Time-Sensitive Software-Defined Networks (TSSDN), which
provide real-time guarantees for the time-triggered traffic in time-sensitive
systems while also transporting non-time-sensitive traffic. TSSDN provides
these guarantees by bounding the non-deterministic queuing delays for
time-sensitive traffic. To this end, it exploits the logical centralization
paradigm of software-defined networking to compute a transmission schedule for
time-sensitive traffic initiated by the end systems based on a global view. In
particular, we present various Integer Linear Program (ILP) formulations that
solve the combined problem of routing and scheduling time-triggered traffic.
Moreover, we show that end systems can comply with a given schedule with high
precision using user-space packet processing frameworks. Our evaluations show
that TSSDN has deterministic end-to-end delays ($<$= 14 us on our benchmark
topology) with low and bounded jitter ($<$= 7 us).},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-31&engl=0}
}
@inproceedings {INPROC-2016-11,
author = {Zohaib Riaz and Frank D{\"u}rr and Kurt Rothermel},
title = {{On the Privacy of Frequently Visited User Locations}},
booktitle = {Proceedings of the Seventeenth International Conference on Mobile Data Management: MDM'16; Porto, Portugal, June 13-16, 2016},
address = {Porto, Portugal},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2016},
keywords = {Location Privacy, Location-based Applications, Semantic Locations, Visit-Frequency, Frequent locations, Geo-social networking, Location Servers, Non-trusted systems},
language = {Englisch},
cr-category = {K.4.1 Computers and Society Public Policy Issues,
C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-11/INPROC-2016-11.pdf},
contact = {zohaib.riaz@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {With the fast adoption of location-enabled devices, Location-based Applications
(LBAs) have become widely popular. While LBAs enable highly useful concepts
such as geo-social networking, their use also raises serious privacy concerns
as it involves sharing of location data with non-trusted third parties. In this
respect, we propose an approach that protects the frequently visited locations
of users, e.g., a bar, against inferences from longterm monitoring of their
location data. Such inferences equate a privacy leak as they reveal a user{\^a}€™s
personal behavior and interests to possibly malicious non-trusted parties.
To this end, we first present a study of a dataset of location check-ins to
show the existence of this threat among users of LBAs. We then propose our
approach to protect visit-frequency of the users to different locations by
distributing their location data among multiple third-party Location Servers.
This distribution not only serves to avoid a single point of failure for
privacy in our system, it also allows the users to control which LBA accesses
what information about them. We also describe a number of possible attacks
against our privacy approach and evaluate them on real-data from the check-ins
dataset. Our results show that our approach can effectively hide the frequent
locations while supporting good quality-of-service for the LBAs.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-11&engl=0}
}
@inproceedings {INPROC-2015-59,
author = {Simon Gansel and Stephan Schnitzer and Ahmad Gilbeau-Hammoud and Viktor Friesen and Frank D{\"u}rr and Kurt Rothermel and Christian Maih{\"o}fer and Ulrich Kr{\"a}mer},
title = {{Context-aware Access Control in Novel Automotive HMI Systems}},
booktitle = {Proceedings of 11th International Conference on Information Systems Security, ICISS 2015, Kolkata, India},
editor = {Sushil Jajodia and Chandan Mazumdar},
publisher = {Springer International Publishing},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {118--138},
type = {Konferenz-Beitrag},
month = {Dezember},
year = {2015},
isbn = {10.1007/978-3-319-26961-0_8},
language = {Englisch},
cr-category = {D.4.6 Operating Systems Security and Protection},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-59/INPROC-2015-59.pdf,
http://link.springer.com/chapter/10.1007%2F978-3-319-26961-0_8},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {The growing relevance of vehicular applications like media player, navigation
system, or speedometer using graphical presentation has lead to an increasing
number of displays in modern cars. This effectuates the desire for flexible
sharing of all the available displays between several applications. However,
automotive requirements include many regulations to avoid driver distraction to
ensure safety. To allow for safe sharing of the available screen surface
between the many safety-critical and non-safety-critical applications, adequate
access control systems are required. We use the notion of $\backslash$emph{contexts} to
dynamically determine, which application is allowed to access which display
area. A context can be derived from vehicle sensors (e.g., the current speed),
or be an application-specific state (e.g., which menu item is selected). We
propose an access control model that is inherently aware of the context of the
car and the applications. It provides delegation of access rights to display
areas by applications. We implemented a proof-of-concept implementation that
demonstrates the feasibility of our concept and evaluated the latency
introduced by access control. Our results show that the delay reacting on
dynamic context changes is small enough for automotive scenarios.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-59&engl=0}
}
@inproceedings {INPROC-2015-54,
author = {Simon Gansel and Stephan Schnitzer and Riccardo Cecolin and Frank D{\"u}rr and Kurt Rothermel and Christian Maih{\"o}fer},
title = {{Efficient Compositing Strategies for Automotive HMI Systems}},
booktitle = {10th IEEE International Symposium on Industrial Embedded Systems (SIES), Siegen, Germany, 2015},
address = {Siegen},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2015},
doi = {10.1109/SIES.2015.7185036},
keywords = {CPU execution time; automotive HMI systems; automotive embedded platforms; cache-hybrid compositing; graphical functions; off-screen buffers; power consumption; vehicular applications},
language = {Englisch},
cr-category = {D.4.9 Systems Programs and Utilities,
H.5.2 Information Interfaces and Presentation User Interfaces,
I.3.6 Computer Graphics Methodology and Techniques},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-54/INPROC-2015-54.pdf,
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7185036&isnumber=7185026},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {The relevance of graphical functions in vehicular applications has increased
significantly during the last years. Modern cars are equipped with multiple
displays used by different applications such as speedometer, navigation system,
or media players. The rendered output of the applications is stored in
so-called off-screen buffers and then bitblitted to the screen buffer at the
respective window sizes and positions. To guarantee the visibility of the
potentially overlapping windows, the compositing has to match the z-order of
the windows. To this end, two common compositing strategies Tile compositing
and Full compositing are used, each having performance issues depending on how
windows overlap. Since automotive embedded platforms are restricted in power
consumption, installation space, and hardware cost, their performance is
limited which effectuates the need for highly efficient bitblitting. In order
to increase the performance in compositing the windows, we propose Hybrid
Compositing which predicts the required bitblitting time and chooses the most
efficient strategy for each pair of overlapping windows. Using various
scenarios we show that our approach is faster than the other strategies. In
addition, we propose CacheHybrid Compositing which reduces the CPU execution
time of our approach by up to 66 \%. In case of an automotive scenario we show
that our optimized approach saves up to 51 \% bitblitting time compared to
existing approaches.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-54&engl=0}
}
@inproceedings {INPROC-2015-49,
author = {Thomas Kohler and Frank D{\"u}rr and Kurt Rothermel},
title = {{Update Consistency in Software-defined Networking based Multicast Networks}},
booktitle = {Proceedings of the 2015 IEEE Conference on Network Function Virtualization and Software Defined Networks (NFV-SDN), San Francisco, USA, November 18-21, 2015},
address = {San Francisco, USA},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {177--183},
type = {Konferenz-Beitrag},
month = {September},
year = {2015},
doi = {10.1109/NFV-SDN.2015.7387424},
keywords = {Software-defined Networking; Multicast communication; Computer network management; Concurrency Control},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.3 Network Operations,
C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-49/INPROC-2015-49.pdf,
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=7387424},
contact = {thomas.kohler@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {When applying updates on distributed network elements with SDN, intra-update
states may violate desired network properties, such as drop- and loop-freeness.
Current stateless approaches cannot guarantee the constancy of arbitrary
network invariants (correctness) in general, yet update procedures guaranteeing
certain invariants do exist. In this paper, we investigate on update
consistency for the case of multicast routing and show that there is no correct
update procedure w.r.t. both drop- and duplicate-freeness. We show that certain
updates of multicast routes inherently raise a concurrency issue, which
necessarily results in the occurrence of either drops or duplicates.
Furthermore, we present a generic update procedure for multicast routing
updates that identifies concurrency-relevant update steps. This procedure
allows for the selection of an update strategy, such that either drops or
duplicates are avoided. These effects can severely degrade network performance
or quality of experience. To investigate the implications of drops and
duplicates, we evaluate their frequencies and impact for wide-area network
scenarios both, analytically and empirically, through direct measurement in the
data plane under update.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-49&engl=0}
}
@inproceedings {INPROC-2015-48,
author = {Florian Berg and Frank D{\"u}rr and Kurt Rothermel},
title = {{Increasing the Efficiency of Code Offloading through Remote-side Caching}},
booktitle = {Proceedings of the IEEE 11th International Conference on Wireless and Mobile Computing, Networking and Communications: WiMob'15; Abu-Dhabi, United Arab Emirates (UAE), October 19-21, 2015},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {573--580},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2015},
doi = {10.1109/WiMOB.2015.7348013},
keywords = {Mobile Cloud Computing; Code Offloading; Distributed Execution; Data Replication; Function Caching},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {http://dx.doi.org/10.1109/WiMOB.2015.7348013},
contact = {Florian.Berg@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {End users execute today on their smart phones different kinds of mobile
applications like calendar apps or high-end mobile games, differing in local
resource usage. Utilizing local resources of a smart phone heavily, like
playing high-end mobile games, drains its limited energy resource in few hours.
To prevent the limited energy resource from a quick exhaustion, smart phones
benefit from executing resource-intensive application parts on a remote server
in the cloud (code offloading). During the remote execution on the remote
server, a smart phone waits in idle mode until it receives a result. However,
code offloading introduces computation and communication overhead, which
decreases the energy efficiency and induces monetary cost. For instance,
sending or receiving execution state information to or from a remote server
consumes energy. Moreover, executing code on a remote server instance in a
commercial cloud causes monetary cost. To keep consumed energy and monetary
cost low, we present in this paper the concept of remote-side caching for code
offloading, which increases the efficiency of code offloading. The remote-side
cache serves as a collective storage of results for already executed
application parts on remote servers, avoiding the repeated execution of
previously run application parts. The smart phone queries the remote-side cache
for corresponding results of resource-intensive application parts. In case of a
cache hit, the smart phone gets immediately a result and continues the
application execution. Otherwise, it migrates the application part and waits
for a result of the remote execution. We show in our evaluation that the use of
a remote-side cache decreases energy consumption and monetary cost for mobile
applications by up to 97\% and 99\%, respectively.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-48&engl=0}
}
@inproceedings {INPROC-2015-41,
author = {Naresh Ganesh Nayak and Frank D{\"u}rr and Kurt Rothermel},
title = {{Software-defined Environment for Reconfigurable Manufacturing Systems}},
booktitle = {Proceedings of the 5th International Conference on Internet of Things (IoT 2015)},
address = {Seoul, South Korea},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2015},
keywords = {Time-sensitive networks; Industry 4.0; Quality of service; Genetic Algorithm; Software-defined networks},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.3 Network Operations},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-41/INPROC-2015-41.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Conventional manufacturing systems like assembly lines cannot handle the
constantly changing requirements of a modern-day manufacturer, which are driven
by volatile market demands. In a bid to satisfy such requirements, modern
manufacturing systems, comprising innumerable cyber-physical systems (CPS), aim
to be reconfigurable. CPS implement production processes through an ICT
infrastructure networked with sensors and actuators embedded in the shop floor.
Reconfigurability, in context of manufacturing systems, must include the entire
system of networked components and hence requires a flexible ICT
infrastructure. Providing flexible ICT infrastructures, often, comes at the
cost of diluted quality of service (QoS) guarantees. This, however, is not an
option for manufacturing systems, most of which require strict QoS guarantees
to function correctly. To overcome this obstacle, we propose a new
software-defined environment (SDE) for reconfigurable manufacturing systems
with real-time properties in this paper. Software-defined environment is an
emerging technology that provides flexible ICT infrastructures modifiable using
software. Our contributions include an SDE-based system architecture for
dynamically configuring the underlying infrastructure for a manufacturing
system. In particular, we focus on configuring the network for the
time-sensitive communication flows essential for realising CPS. Moreover, we
propose a pair of routing algorithms to calculate routes for these flows while
configuring the network.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-41&engl=0}
}
@inproceedings {INPROC-2015-36,
author = {Christoph Dibak and Frank D{\"u}rr and Kurt Rothermel},
title = {{Numerical Analysis of Complex Physical Systems on Networked Mobile Devices}},
booktitle = {Proceedings of the 12th IEEE International Conference on Mobile Ad hoc and Sensor Systems (MASS 2015); Dallas, USA, October 19-22 2015},
address = {Dallas},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--9},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2015},
keywords = {mobile cloud computing; numerical applications; mobile cyber-physical systems; augmented reality},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
C.4 Performance of Systems,
G.1.0 Numerical Analysis General},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-36/INPROC-2015-36.pdf},
contact = {Christoph Dibak christoph.dibak@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Recently, a new class of mobile applications has appeared that takes into
account the behavior of physical phenomenon. Prominent examples of such
applications include augmented reality applications visualizing physical
processes on a mobile device or mobile cyber-physical systems like autonomous
vehicles or robots. Typically, these applications need to solve partial
differential equations (PDE) to simulate the behavior of a physical system.
There are two basic strategies to numerically solve these PDEs: (1) offload all
computations to a remote server; (2) solve the PDE on the resource-constrained
mobile device. However, both strategies have severe drawbacks. Offloading will
fail if the mobile device is disconnected, and resource constraints require to
reduce the quality of the solution.
Therefore, we propose a new approach for mobile simulations using a hybrid
strategy that is robust to communication failures and can still benefit from
powerful server resources. The basic idea of this approach is to dynamically
decide on the placement of the PDE solver based on a prediction of the wireless
link availability using Markov Chains. Our tests based on measurement in real
cellular networks and real mobile devices show that this approach is able to
keep deadline constraints in more than 61 \% of the cases compared to a pure
offloading approach, while saving up to 74 \% of energy compared to a simplified
approach.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-36&engl=0}
}
@inproceedings {INPROC-2015-06,
author = {Zohaib Riaz and Frank D{\"u}rr and Kurt Rothermel},
title = {{Optimized Location Update Protocols for Secure and Efficient Position Sharing}},
booktitle = {Proceedings of the 2nd International Conference on Networked Systems: NetSys 2015; Cottbus, Germany, March 9-13, 2015},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--8},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2015},
language = {Englisch},
cr-category = {C.2.0 Computer-Communication Networks, General,
K.4.1 Computers and Society Public Policy Issues},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-06/INPROC-2015-06.pdf},
contact = {zohaib.riaz@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Abstract{\^a}€”Although location-based applications have seen fast growth in the
last decade due to pervasive adoption of GPS enabled mobile devices, their use
raises privacy concerns. To mitigate these concerns, a number of approaches
have been proposed in literature, many of which rely on a trusted party to
regulate user privacy. However, trusted parties are known to be prone to data
breaches [1]. Consequently, a novel solution, called Position Sharing, was
proposed in [2] to secure location privacy in fully non-trusted systems. In
Position Sharing, obfuscated position shares of the actual user location are
distributed among several location servers, each from a different provider,
such that there is no single point of failure if the servers get breached.
While Position Sharing can exhibit useful properties such as graceful
degradation of privacy, it incurs significant communication overhead as
position shares are sent to several location servers instead of one.
To this end, we propose a set of location update protocols to minimize the
communication overhead of Position Sharing while maintaining the privacy
guarantees that it originally provided. As we consider the scenario of frequent
location updates, i.e., movement trajectories, our protocols additionally add
protection against an attack based on spatio-temporal correlation in published
locations. By evaluating on a set of real-world GPS traces, we show that our
protocols can reduce the communication overhead by 75\% while significantly
improving the security guarantees of the original Position Sharing algorithm.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-06&engl=0}
}
@inproceedings {INPROC-2014-95,
author = {Simon Gansel and Stephan Schnitzer and Ahmad Gilbeau-Hammoud and Viktor Friesen and Frank D{\"u}rr and Kurt Rothermel and Christian Maih{\"o}fer},
title = {{An access control concept for novel automotive HMI systems}},
booktitle = {Proceedings of the 19th ACM symposium on Access control models and technologies, 2014, London, Ontario, Canada.},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {17--28},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2014},
isbn = {978-1-4503-2939-2},
doi = {10.1145/2613087.2613104},
keywords = {Access Control; State-based Model; Automotive; Windows},
language = {Englisch},
cr-category = {D.4.6 Operating Systems Security and Protection,
H.5.2 Information Interfaces and Presentation User Interfaces},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-95/INPROC-2014-95.pdf,
http://dl.acm.org/citation.cfm?id=2613104},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {The relevance of graphical functions in vehicular applications has increased
significantly during the few last years. Modern cars are equipped with multiple
displays used by different applications such as speedometer or navigation
system. However, so far applications are restricted to using dedicated
displays. In order to increase flexibility, the requirement of sharing displays
between applications has emerged. Sharing displays leads to safety and security
concerns since safety-critical applications as the dashboard warning lights
share the same displays with uncritical or untrusted applications like the
navigation system or third-party applications. To guarantee the safe and secure
sharing of displays, we present a formal model for defining and controlling the
access to display areas in this paper. We prove the validity of this model, and
present a proof-of-concept implementation to demonstrate the feasibility of our
concept.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-95&engl=0}
}
@inproceedings {INPROC-2014-94,
author = {Stephan Schnitzer and Simon Gansel and Frank D{\"u}rr and Kurt Rothermel},
title = {{Concepts for execution time prediction of 3D GPU rendering}},
booktitle = {9th IEEE International Symposium on Industrial Embedded Systems (SIES), 2014, pp.160-169, 18-20 June 2014},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {160--169},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2014},
isbn = {10.1109/SIES.2014.6871200},
keywords = {3D-rendering; GPU-scheduling; embedded systems; execution time prediction; real-time},
language = {Englisch},
cr-category = {H.5.2 Information Interfaces and Presentation User Interfaces,
I.3.m Computer Graphics Miscellaneous},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-94/INPROC-2014-94.pdf,
http://dx.doi.org/10.1109/SIES.2014.6871200},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {The relevance of graphical functions in vehicular applications has increased
significantly during the last years. Modern cars are equipped with multiple
displays used by different applications such as speedometer, navigation system,
or media players. The recent trend towards hardware consolidation to reduce
hardware cost, installation space, and energy consumption, causes graphical 3D
applications of different safety-criticality to share a single GPU. This
requires effective real-time GPU scheduling concepts to ensure safety and
isolation for 3D rendering. Since current GPUs are not preemptible, a
deadline-based scheduler must know the GPU execution time of GPU commands in
advance. In this work, we present a novel framework to measure and predict the
execution time of GPU commands using OpenGL ES 2.0. We present prediction
models for the main GPU commands relevant for 3D rendering, namely, FLUSH,
CLEAR, and DRAW. For the DRAW command we propose to use the 3D bounding box of
the rendered model and apply the vertex shader projection to heuristically
estimate the number of fragments rendered. We finally present the
implementation and evaluation of our framework, which demonstrates its
feasibility and shows that good prediction accuracy can be achieved. In our
evaluation using realistic scenarios the absolute prediction error of the DRAW
command did not exceed 260 µs.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-94&engl=0}
}
@inproceedings {INPROC-2014-78,
author = {Florian Berg and Frank D{\"u}rr and Kurt Rothermel},
title = {{Optimal Predictive Code Offloading}},
booktitle = {Proceedings of the 11th International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {Dezember},
year = {2014},
doi = {10.4108/icst.mobiquitous.2014.258023},
keywords = {Code Offloading; Markov chain; Link quality},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {http://dl.acm.org/citation.cfm?id=2692985},
contact = {Florian.Berg@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Modern mobile devices like smart phones and tablets are equipped with powerful
processing and memory resources, enabling resource-intensive mobile
applications such as high-end mobile games. The main limitation, however,
remains the energy resource. To improve the energy efficiency, code offloading
has been proposed, which offloads code to remote servers and transfers the
results back to the mobile device. Although several approaches have shown that
code offloading improves energy efficiency significantly in general, they
largely neglect the adverse effects of network disconnections. Therefore, we
have proposed the concept of preemptive code offloading to improve energy
efficiency also under link failures. It transmits so-called safe-points between
server and mobile device during remote execution, enabling the re-use of
partial remote results after link failures. In this paper, we improve our basic
preemptive code offloading approach by optimizing the time when to generate and
transmit safe-points to minimize the communication overhead and maximize energy
efficiency. To find the optimal safe-point schedule, we use a predictive
approach that predicts the mobile link quality in order to send safe-points
before network disconnections. Moreover, we consider additional deadline
constraints for code execution to ensure a minimal responsiveness of offloaded
applications despite link failures. Our evaluation results show that energy
efficiency can be improved significantly using our predictive offloading
approach.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-78&engl=0}
}
@inproceedings {INPROC-2014-32,
author = {Florian Berg and Frank D{\"u}rr and Kurt Rothermel},
title = {{Increasing the Efficiency and Responsiveness of Mobile Applications with Preemptable Code Offloading}},
booktitle = {Proceedings of the 3rd IEEE International Conference on Mobile Services: MS'14; Anchorage, Alaska, USA, June 27 - July 2, 2014},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {76--83},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2014},
doi = {10.1109/MobServ.2014.20},
keywords = {Distributed Systems, Code Offloading, Safe-points, Mobile Cloud Computing, Efficiency, Responsiveness},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-32/INPROC-2014-32.pdf,
http://dx.doi.org/10.1109/MobServ.2014.20},
contact = {Florian.Berg@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Mobile applications are getting more and more sophisticated and demanding.
Although the processing, memory, and storage resources of mobile devices are
constantly increasing to enable such resource-demanding mobile applications,
battery capacity is still the main limiting factor. To solve this problem,
mobile code offloading approaches can be used to offload parts of a mobile
application to remote servers and utilize the resources of cloud services. In
this paper, we propose a novel code offloading approach that makes code
offloading robust against communication link failures, which are still a major
problem of mobile systems. To this end, we propose preemptable code offloading.
It allows for interrupting the offloading process and continuing the remote
execution locally after a link failure, without abandoning the complete result
calculated remotely so far. The basic idea of our approach is to create
safe-points of the remote execution and transmit these intermediate results
back to the mobile device. After a link failure, the mobile device can now
continue execution from the last transmitted safe-point. Although safe-points
induce communication and energy overhead, our evaluations show that using an
optimized safe-point schedule this overhead quickly pays off under link
failures. Besides reducing the overall energy consumption significantly,
responsiveness also benefits from safe-points by meeting given execution
deadlines after link failures.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-32&engl=0}
}
@inproceedings {INPROC-2014-03,
author = {Damian Philipp and Patrick Baier and Christoph Dibak and Frank D{\"u}rr and Kurt Rothermel and Susanne Becker and Michael Peter and Dieter Fritsch},
title = {{MapGENIE: Grammar-enhanced Indoor Map Construction from Crowd-sourced Data}},
booktitle = {Proceedings of the 12th IEEE International Conference on Pervasive Computing and Communications (PerCom 2014)},
address = {Budapest, Hungary},
publisher = {IEEE Computer Society Conference Publishing Services},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {139--147},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2014},
doi = {10.1109/PerCom.2014.6813954},
keywords = {Public Sensing; Opportunistic Sensing; Indoor Mapping; Map Reconstruction; IMU; Grammar},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-03/INPROC-2014-03.pdf,
http://dx.doi.org/10.1109/PerCom.2014.6813954},
contact = {damian.philipp@ipvs.uni-stuttgart.de patrick.baier@ipvs.uni-stuttgart.de christoph.dibak@ipvs.uni-stuttgart.de frank.duerr@ipvs.uni-stuttgart.de susanne.becker@ifp.uni-stuttgart.de michael.peter@ifp.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {While location-based services are already well established in outdoor
scenarios, they are still not available in indoor environments. The reason for
this can be found in two open problems: First, there is still no off-the-shelf
indoor positioning system for mobile devices and, second, indoor maps are not
publicly available for most buildings. While there is an extensive body of work
on the first problem, the efficient creation of indoor maps remains an open
challenge.
We tackle the indoor mapping challenge in our MapGENIE approach that
automatically derives indoor maps from traces collected by pedestrians moving
around in a building. Since the trace data is collected in the background from
the pedestrians' mobile devices, MapGENIE avoids the labor-intensive task of
traditional indoor map creation and increases the efficiency of indoor mapping.
To enhance the map building process, MapGENIE leverages exterior information
about the building and uses grammars to encode structural information about the
building. Hence, in contrast to existing work, our approach works without any
user interaction and only needs a small amount of traces to derive the indoor
map of a building. To demonstrate the performance of MapGENIE, we implemented
our system using Android and a foot-mounted IMU to collect traces from
volunteers. We show that using our grammar approach, compared to a purely
trace-based approach we can identify up to four times as many rooms in a
building while at the same time achieving a consistently lower error in the
size of detected rooms.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-03&engl=0}
}
@inproceedings {INPROC-2013-67,
author = {Simon Gansel and Stephan Schnitzer and Frank D{\"u}rr and Kurt Rothermel and Christian Maih{\"o}fer},
title = {{Towards Virtualization Concepts for Novel Automotive HMI Systems}},
booktitle = {Proceedings of 4th IFIP TC 10 International Embedded Systems Symposium, IESS 2013, Paderborn, Germany, June 17-19, 2013.},
publisher = {Springer Berlin Heidelberg},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
series = {Embedded Systems: Design, Analysis and Verification},
volume = {403},
pages = {193--204},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2013},
isbn = {978-3-642-38853-8},
isbn = {10.1007/978-3-642-38853-8_18},
keywords = {Virtualization; Automotive HMI},
language = {Englisch},
cr-category = {H.5.2 Information Interfaces and Presentation User Interfaces,
J.7 Computers in Other Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-67/INPROC-2013-67.pdf,
http://link.springer.com/chapter/10.1007%2F978-3-642-38853-8_18},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Many innovations in the automotive industry are based on electronics and
software, which has led to a steady increase of electronic control units (ECU)
in cars. This brought up serious scalability and complexity issues in terms of
cost, installation space, and energy consumption. In order to tackle these
problems, there is a strong interest to consolidate ECUs using virtualization
technologies. However, current efforts largely neglect legal constraints and
certification issues and the resulting technical requirements.
In this paper, we focus on the consolidation of graphics hardware through
virtualization, which received a lot of interest in the car industry due to the
growing relevance of HMI systems such as head unit and instrument cluster in
modern cars. First, we investigate relevant ISO standards and legal
requirements and derive seven technical requirements for a virtualized
automotive HMI system. Based on these requirements, we present the concept for
a Virtualized Automotive Graphics System (VAGS) that allows for the
consolidation of mixed-criticality graphics ECUs.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-67&engl=0}
}
@inproceedings {INPROC-2013-59,
author = {Marius Wernke and Frank D{\"u}rr and Kurt Rothermel},
title = {{Protecting Movement Trajectories through Fragmentation}},
booktitle = {Proceedings of the Tenth Annual International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services (MobiQuitous '13)},
address = {Tokyo, Japan},
publisher = {ICST},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--12},
type = {Konferenz-Beitrag},
month = {Dezember},
year = {2013},
keywords = {Location based applications; position sharing; privacy},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-59/INPROC-2013-59.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Location-based applications (LBAs) like geo-social networks, points of interest
finders, and real-time traffic monitoring applications have entered people's
daily life. Advanced LBAs rely on location services (LSs) managing movement
trajectories of multiple users in a scalable fashion. However, exposing
trajectory information raises user privacy concerns, in particular if LSs are
non-trusted. For instance, an attacker compromising an LS can use the retrieved
user trajectory for stalking, mugging, or to trace user movement. To limit the
misuse of trajectory data, we present a new approach for the secure management
of trajectories on non-trusted servers. Instead of providing the complete
trajectory of a user to a single LS, we split up the trajectory into a set of
fragments and distribute the fragments among LSs of different providers. By
distributing fragments, we avoid a single point of failure in case of
compromised LSs, while different LBAs can still reconstruct the trajectory
based on user-defined access rights.
In our evaluation, we show the effectiveness of our approach by using real
world trajectories and realistic attackers using map knowledge and statistical
information to predict and reconstruct the user's movement.
Location management, fragmentation, trajectories, privacy},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-59&engl=0}
}
@inproceedings {INPROC-2013-52,
author = {Damian Philipp and Jaroslaw Stachowiak and Frank D{\"u}rr and Kurt Rothermel},
title = {{Model-Driven Public Sensing in Sparse Networks}},
booktitle = {Proceedings of the 10th International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services},
publisher = {Springer},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
series = {LNCS},
pages = {1--12},
type = {Konferenz-Beitrag},
month = {Dezember},
year = {2013},
keywords = {model-driven; energy optimization; public sensing; opportunistic sensing; adaptive algorithm; mobility},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-52/INPROC-2013-52.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Public Sensing (PS) is a recent trend for building large-scale sensor data
acquisition systems using commodity smartphones. Limiting the energy drain on
participating devices is a major challenge for PS, as otherwise people will
stop sharing their resources with the PS system. Existing solutions for
limiting the energy drain through model-driven optimizations are limited to
dense networks where there is a high probability for every point of interest to
be covered by a smartphone. In this work, we present an adaptive model-driven
PS system that deals with both dense and sparse networks. Our evaluations show
that this approach improves data quality by up to 41 percentage points while
enabling the system to run with a greatly reduced number of participating
smartphones. Furthermore, we can save up to 81\% of energy for communication and
sensing while providing data matching an error bound of 1°C up to 96\% of the
time.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-52&engl=0}
}
@inproceedings {INPROC-2013-51,
author = {Marius Wernke and Frank D{\"u}rr and Kurt Rothermel},
title = {{Speed Protection Algorithms for Privacy-aware Location Management}},
booktitle = {Proceedings of the IEEE 9th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob 2013).},
address = {Lyon, France},
publisher = {IEEE Xplore},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {355--362},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2013},
keywords = {Location-based applications; location-based services; speed protection; movement trajectory; location management; location privacy},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-51/INPROC-2013-51.pdf,
www.ieeexplore.ieee.org,
www.PriLoc.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Nowadays, millions of users share their complete movement trajectory online
when using real-time traffic monitoring applications, pay-as-you-drive
insurances, or when sharing their last road trip with friends. However, many
users still hesitate to use location-based applications as they are not willing
to reveal, for instance, their driving behavior or the occurrence of a speeding
violation.
Therefore, we present novel speed protection algorithms protecting users from
revealing a violation of given speed limits when using location-based
applications. Our algorithms support time-based and distance-based position
updates. To protect positions indicating a speeding violation, we either adjust
temporal information by delaying position updates or adjust their spatial
information. We evaluate our algorithms by using real world traces and show
that the protected movement trajectory of the user is of high quality even
after removing speeding violations.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-51&engl=0}
}
@inproceedings {INPROC-2013-35,
author = {Patrick Baier and Frank D{\"u}rr and Kurt Rothermel},
title = {{Efficient Distribution of Sensing Queries in Public Sensing Systems}},
booktitle = {Proceedings of the 10th IEEE International Conference on Mobile Ad-hoc and Sensor Systems (MASS 2013)},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--9},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2013},
language = {Deutsch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-35/INPROC-2013-35.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {The advent of mobile phones paved the way for a new paradigm for gathering
sensor data termed Public Sensing (PS). PS uses built-in sensors of mobile
devices to opportunistically gather sensor data. For instance, the microphones
of a crowd of mobile phones can be used to capture sound samples, which can be
used to construct a city noise map.
A great challenge of PS is to reduce the energy consumption of mobile devices
since otherwise users might not be willing to participate. One crucial part in
the overall power consumption is the energy required for the communication
between the mobile devices and the infrastructure. In particular, the
communication required for sending sensing queries to mobile devices has been
largely neglected in the related work so far.
Therefore, in this paper, we address the problem of minimizing communication
costs for the distribution of sensing queries. While existing systems simply
broadcast sensing queries to all devices, we use a selective strategy by
addressing only a subset of devices. In order not to negatively affect the
quality of sensing w.r.t. completeness, this subset is carefully chosen based
on a probabilistic sensing model that defines the probability of mobile devices
to successfully perform a given sensing query.
Our evaluations show that with our optimized sensing query distribution, the
energy consumption can be reduced by more than 70\% without significantly
reducing the quality of sensing.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-35&engl=0}
}
@inproceedings {INPROC-2013-33,
author = {Patrick Baier and Frank D{\"u}rr and Kurt Rothermel},
title = {{Opportunistic Position Update Protocols for Mobile Devices}},
booktitle = {Proceedings of the International Joint Conference on Pervasive and Ubiquitous Computing (UbiComp 2013)},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--9},
type = {Konferenz-Beitrag},
month = {September},
year = {2013},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-33/INPROC-2013-33.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Many location-based applications such as geo-social networks rely on location
services storing mobile object positions. To update positions on location
servers, position update protocols are used. On the one hand, these protocols
decide when an update has to be sent to ensure a certain quality of position
information. On the other hand, they try to minimize the energy consumption of
the mobile device by reducing communication to a minimum.
In this paper, we show how to improve the energy efficiency of different update
protocols by taking the energy characteristics of the mobile network interface
into account. In particular, we show that the energy consumption can be reduced
on average by 70\% using an opportunistic update strategy sending position
updates together with messages of other applications. We present a Markov model
to predict the arrival of messages and an online optimization algorithm
calculating an optimized schedule to send position updates.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-33&engl=0}
}
@inproceedings {INPROC-2013-27,
author = {Boris Koldehofe and Frank D{\"u}rr and Muhammad Adnan Tariq},
title = {{Event-based Systems Meet Software-defined Networking}},
booktitle = {Proceedings of the 7th ACM International Conference on Distributed Event-Based Systems (DEBS)},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
pages = {271--280},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2013},
doi = {10.1145/2488222.2488270},
keywords = {Software-defined Networking, Event-based Systems, Content-based Routing, Publish/Subscribe, Network Virtualization},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.4 Distributed Systems,
D.2.11 Software Engineering Software Architectures},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-27/INPROC-2013-27.pdf,
http://dx.doi.org/10.1145/2488222.2488270},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
abstract = {Software-defined networking (SDN) is a recent development in the area of
communication networks with tremendous support by key players building the next
generation of computer hardware and software. This development will have
significant impact on how communication middleware---in particular, future
distributed event-based systems---can be designed. While currently the
communication middleware has no possibility to directly influence the
properties of its underlying communication channels on the network layer, SDN
enables communication middleware to control and flexibly adapt the forwarding
of communication flows in the underlying network. In addition to the immediate
implication to local area networks such as data center networks, campus
networks, or company networks, novel trends like network virtualization may
even support Internet-wide distributed applications to benefit from SDN in the
future. This paper gives an introduction on how to utilize SDN-concepts for
improving the performance of event-based middleware and to test their behavior.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-27&engl=0}
}
@inproceedings {INPROC-2013-22,
author = {Frank D{\"u}rr},
title = {{Improving the Efficiency of Cloud Infrastructures with Elastic Tandem Machines}},
booktitle = {Proceedings of the 6th International Conference on Cloud Computing (Cloud 2013)},
address = {Santa Clara, CA, USA},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--8},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2013},
keywords = {cloud computing; infrastructure as a service; efficiency; energy, elasticity; scaling; system on a chip; software-defined networking; green computing},
language = {Englisch},
cr-category = {C.2.3 Network Operations,
C.2.4 Distributed Systems,
C.2.1 Network Architecture and Design,
C.4 Performance of Systems,
C.5 Computer System Implementation,
H.3.4 Information Storage and Retrieval Systems and Software},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-22/INPROC-2013-22.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In this paper, we propose a concept for improving the energy efficiency and
resource utilization of cloud infrastructures by combining the benefits of
heterogeneous machine instances. The basic idea is to integrate low-power
system on a chip (SoC) machines and high-power virtual machine instances into
so-called Elastic Tandem Machine Instances (ETMI). The low-power machine serves
low load and is always running to ensure the availability of the ETMI. When
load rises, the ETMI scales up automatically by starting the high-power
instance and handing over traffic to it. For the non-disruptive transition from
low-power to high-power machines and vice versa, we present a handover
mechanism based on software-defined networking technologies. Our evaluations
show the applicability of low-power SoC machines to serve low load efficiently
as well as the desired scalability properties of ETMIs.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-22&engl=0}
}
@inproceedings {INPROC-2013-04,
author = {Damian Philipp and Jaroslaw Stachowiak and Patrick Alt and Frank D{\"u}rr and Kurt Rothermel},
title = {{DrOPS: Model-Driven Optimization for Public Sensing Systems}},
booktitle = {2013 IEEE International Conference on Pervasive Computing and Communications (PerCom 2013)},
address = {San Diego, CA, USA},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {185--192},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2013},
doi = {10.1109/PerCom.2013.6526731},
keywords = {Data acquisition; Distributed computing; Wireless sensor networks; Public Sensing; Opportunistic Sensing; Smartphone; Model-Driven Data Acquisition; Quality aware; Adaptive, autonomic and context-aware computing; Energy-efficient and green pervasive computing; Innovative pervasive computing applications; Pervasive opportunistic communications and applications; Participatory, opportunistic and social sensing; Sensors and RFID in pervasive systems; Smart devices and intelligent environments},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-04/INPROC-2013-04.pdf,
http://www.comnsense.de,
http://dx.doi.org/10.1109/PerCom.2013.6526731},
contact = {Damian Philipp damian.philipp@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {The proliferation of modern smartphones has given rise to Public Sensing, a new
paradigm for data acquisition systems utilizing smartphones of mobile
participants. In this paper, we present DrOPS, a system for improving the
efficiency of data acquisition in Public Sensing systems. DrOPS utilizes a
model-driven approach, where the number of required readings from mobile
smartphones is reduced by inferring readings from the model. Furthermore, the
model can be used to infer readings for positions where no sensor is available.
The model is directly constructed from the observed phenomenon in an online
fashion. Using such models together with a client-specified quality bound, we
can significantly reduce the effort for data acquisition while still reporting
data of required quality to the client. To this effect, we develop a set of
online learning and control algorithms to create and validate the model of the
observed phenomenon and present a sensing task execution system utilizing our
algorithms in this paper. Our evaluations show that we obtain models in a
matter of just hours or even minutes. Using the model-driven approach for
optimizing the data acquisition, we can save up to 80\% of energy for
communication and provide inferred temperature readings for uncovered positions
matching an error-bound of 1°C up to 100\% of the time.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-04&engl=0}
}
@inproceedings {INPROC-2012-49,
author = {Marius Wernke and Frank D{\"u}rr and Kurt Rothermel},
title = {{Efficient Position Sharing for Location Privacy using Binary Space Partitioning}},
booktitle = {Proceedings of the Ninth Annual International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services (MobiQuitous '12)},
address = {Beijing, People's Republic of China},
publisher = {ICST},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--12},
type = {Konferenz-Beitrag},
month = {Dezember},
year = {2012},
keywords = {Position Sharing; Location Privacy; Location Based Applications; Privacy},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-49/INPROC-2012-49.pdf,
http://www.priloc.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Millions of users use location-based applications (LBAs) to share their
positions with friends, request information from points of interest finders, or
get notifications from event finders, etc. Such LBAs are typically based on
location servers (LSs) managing mobile object positions in a scalable fashion.
However, storing precise user positions on LSs raises privacy concerns, in
particular, if LS providers are non-trusted. To solve this problem, we present
PShare-BSP, a novel approach for the secure management of private user
positions on non-trusted LSs. PShare-BSP splits up precise user positions into
position shares and distributes them to different LSs of different providers.
Thus, a compromised provider only reveals user positions with degraded
precision. Nevertheless, LBAs can combine several shares from different LSs to
increase their precision.
PShare-BSP improves on our previous position sharing approaches: It uses a
deterministic share generation approach based on binary space partitioning to
avoid probabilistic attacks based, for instance, on Monte Carlo simulations.
Moreover, it significantly decreases the computational complexity and increases
the efficiency by reducing the update costs for succeeding position updates.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-49&engl=0}
}
@inproceedings {INPROC-2012-41,
author = {Boris Koldehofe and Frank D{\"u}rr and Muhammad Adnan Tariq and Kurt Rothermel},
title = {{The Power of Software-defined Networking: Line-rate Content-based Routing Using OpenFlow}},
booktitle = {Proceedings of the 7th MW4NG Workshop of the 13th International Middleware Conference},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--6},
type = {Workshop-Beitrag},
month = {Dezember},
year = {2012},
doi = {10.1145/2405178.2405181},
keywords = {Content-Based Routing; Publish/Subscribe; Software Defined Networking; SDN; Network Virtualization},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.4 Distributed Systems,
D.2.11 Software Engineering Software Architectures},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-41/INPROC-2012-41.pdf,
http://doi.acm.org/10.1145/2405178.2405181},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {A lot of research effort has been invested to support efficient content-based
routing. Nevertheless, practitioners often fall back to far less expressive
communication paradigms like multicast groups. The benefits of content-based
routing in minimizing bandwidth consumption are often rendered useless by
simpler communication paradigms that rely on line-rate processing of data
packets at the switches of the network providers. Contrary content-based
routing protocols face the inherent overhead in matching the content of events
against subscriptions leading to far lower throughput rates and higher
end-to-end delays. However, recent trends in networking such as software
defined networking in combination with network virtualization have tremendous
potential to change the picture. In our opinion this will significantly
increase acceptance of sophisticated middleware like content-based routing in
the future. To support our claims we outline in this paper a reference
architecture that may be used to build middleware for Future Internet
applications. Furthermore, we provide a solution for realizing content-based
routing at line-rate relying on this reference architecture and illustrate
research problems that need to be addressed.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-41&engl=0}
}
@inproceedings {INPROC-2012-30,
author = {Ben W. Carabelli and Andreas Benzing and Georg Seyboth and Rainer Blind and Mathias B{\"u}rger and Frank D{\"u}rr and Boris Koldehofe and Kurt Rothermel and Frank Allg{\"o}wer},
title = {{Exact Convex Formulations of Network-Oriented Optimal Operator Placement}},
booktitle = {Proceedings of the 51st IEEE Conference on Decision and Control (CDC2012)},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {3777--3782},
type = {Konferenz-Beitrag},
month = {Dezember},
year = {2012},
doi = {10.1109/CDC.2012.6426790},
keywords = {Optimization; Computer networks; Sensor networks},
language = {Englisch},
cr-category = {G.1.6 Numerical Analysis Optimization},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-30/INPROC-2012-30.pdf,
http://dx.doi.org/10.1109/CDC.2012.6426790},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Data processing tasks are increasingly spread across the internet to account
for the spatially distributed nature of many data sources. In order to use
network resources efficiently, subtasks need to be distributed in the network
so data can be filtered close to the data sources. Previous approaches to this
operator placement problem relied on various heuristics to constrain the
complexity of the problem. In this paper, we propose two generic integer
constrained problem formulations: a topology aware version which provides a
placement including the specific network links as well as an end-to-end delay
aware version which relies on the routing capabilities of the network. A linear
programming relaxation for both versions is provided which allows exact and
efficient solution using common solvers.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-30&engl=0}
}
@inproceedings {INPROC-2012-26,
author = {Patrick Baier and Frank D{\"u}rr and Kurt Rothermel},
title = {{TOMP: Opportunistic Traffic Offloading Using Movement Predictions}},
booktitle = {Proceedings of the 37th IEEE Conference on Local Computer Networks (LCN)},
address = {Clearwater},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--8},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2012},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-26/INPROC-2012-26.pdf,
http://www.comnsense.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Recent forecasts predict that the amount of cellular data traffic will
significantly increase within the next few years. The reason for this trend is
on the one hand the high growth rate of mobile Internet users and on the other
hand the growing popularity of high bandwidth streaming applications. Given the
fact that cellular networks (e.g. UMTS) have only limited capacity, the
existing network infrastructure will soon reach its limits. As a result, the
concept of traffic offloading attracts more and more attention in research
since it aims at the reduction of cellular traffic by shifting it to local-area
networks like Wifi. Within the last few years, some first approaches for
automatically offloading cellular traffic were proposed. These approaches
either assume the wide availability of publicly accessible Wifi networks or
knowledge about social relations of mobile users. However, these assumptions
are usually not fulfilled. To face this issue, we developed the TOMP system.
TOMP implements a system to distribute data from the infrastructure to a set of
mobile devices by partly shifting traffic from the cellular network to the
level of inter-device communication. In contrast to the prevailing approaches,
TOMP does not rely on open Wifi networks and only uses information about the
position and speed of mobile device. By using predictions about the future
movement of mobile users, TOMP determines devices that are most suitable
targets for traffic offloading. In this paper we show by simulation that TOMP
can save up to 40\% of cellular messages in comparison to a typical cellular
network.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-26&engl=0}
}
@inproceedings {INPROC-2012-07,
author = {Pavel Skvortsov and Frank D{\"u}rr and Kurt Rothermel},
title = {{Map-aware Position Sharing for Location Privacy in Non-trusted Systems}},
booktitle = {Proceedings of the 10th International Conference on Pervasive Computing (Pervasive 2012)},
editor = {Lecture Notes in Computer Science},
address = {Newcastle, UK},
publisher = {Springer-Verlag},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {388--405},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2012},
keywords = {location-based service; privacy; obfuscation; sharing; map-awareness},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
H.3.5 Online Information Services},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-07/INPROC-2012-07.pdf,
http://www.springerlink.com/content/w682352838637308/,
http://www.priloc.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Many current location-based applications (LBA) such as friend finder services
use information about the positions of mobile users. So-called location
services (LSs) have been proposed to manage these mobile user positions
efficiently. However, managing user positions raises privacy issues, in
particular, if the providers of LSs are only partially trusted. Therefore, the
concept of private position sharing for partially trusted systems was proposed
in the literature. The basic idea of position sharing is to split the precise
user position into a set of position shares of well-defined limited precision
and distribute these shares among LSs of different providers. The main
contributions of this paper are two extended position sharing approaches that
improve the basic position sharing approach in two ways: Firstly, we reduce the
predictability of share generation that allows an attacker to gain further
information from a sub-set of shares to further increase the position
precision. Secondly, we present a position sharing algorithm for constrained
movement scenarios whereas the existing approach was tailored to open space
environments. However, open space approaches are vulnerable to map-based
attacks. Therefore, we present a share generation algorithm that takes map
knowledge into account.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-07&engl=0}
}
@inproceedings {INPROC-2012-06,
author = {Marius Wernke and Frank D{\"u}rr and Kurt Rothermel},
title = {{PShare: Position Sharing for Location Privacy based on Multi-Secret Sharing}},
booktitle = {Proceedings of the 10th IEEE International Conference on Pervasive Computing and Communications (PerCom 2012)},
address = {Lugano, Switzerland},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {153--161},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2012},
keywords = {Location-based applications; privacy; position sharing; location management},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
H.3.5 Online Information Services},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-06/INPROC-2012-06.pdf,
http://www.priloc.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Location-based applications such as Facebook Places, Foursquare, or Loopt
attract millions of users by implementing point of interest finders, friend
finders, geosocial networking, etc. Typically, these applications act as
clients to a location service such as Google Latitude or Yahoo Fire Eagle,
which manage mobile object positions and ensure the scalability to provide
various clients with mobile object positions.
However, exposing precise user positions raises user privacy concerns,
especially if location service providers are not fully trusted, and private
position information could be lost, leaked, stolen, etc. To enable the secure
management of private user positions on non-trusted location servers (LSs), we
present novel position sharing approaches based on the concept of multi-secret
sharing. Our approaches split up a precise user position into position shares,
which are distributed to different LSs of different providers such that a
compromised provider only reveals user positions with degraded precision. On
the other hand, clients can combine several shares queried from different LSs
to increase their provided precision without the need to store precise
information at a single LS.
We propose two position sharing approaches: PShare-SLM is the first position
sharing approach presented so far for symbolic location models. For geometric
location models, we present PShare-GLM, which improves existing geometric
position sharing approaches[DSR11] by considering continuous position updates
and by increasing the robustness against various attacks.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-06&engl=0}
}
@inproceedings {INPROC-2012-01,
author = {Patrick Baier and Frank D{\"u}rr and Kurt Rothermel},
title = {{PSense: Reducing Energy Consumption in Public Sensing Systems}},
booktitle = {Proceedings of the 26th IEEE International Conference on Advanced Information Networking and Applications (AINA-2012)},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {136--143},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2012},
doi = {10.1109/AINA.2012.33},
keywords = {ad-hoc; mobile; public sensing},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-01/INPROC-2012-01.pdf,
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6184863&isnumber=6184848,
http://www.comnsense.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Utilizing peoples' mobile devices for gathering sensor data has attracted a lot
of attention within the last few years. As a result, a great variety of systems
for sensing environmental phenomena like temperature or noise have been
proposed. However, most of these systems do not take into account that mobile
devices have only limited energy resources. For instance, an often assumed
prerequisite is that mobile devices are always aware of their position. Given
the fact that a position fix is a very energy consuming operation, continuous
positioning would quickly drain a device's battery. Since the owners of the
mobile devices will not tolerate a significant reduction of the devices'
battery lifetime, such an approach is not suitable. To address this issue we
present PSense, a flexible system for efficiently gathering sensor data with
mobile devices. By avoiding unnecessary position fixes, PSense reduces the
energy consumption of mobile devices by up to 70\% compared to existing mobile
sensing approaches. This is achieved by introducing an adaptive positioning
mechanism and by utilizing energy efficient short-range communication to
exchange position related information.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-01&engl=0}
}
@inproceedings {INPROC-2011-84,
author = {Stamatia Rizou and Frank D{\"u}rr and Kurt Rothermel},
title = {{Fulfilling End-to-End Latency Constraints in Large-scale Streaming Environments}},
booktitle = {Proceedings of the 30th IEEE International Performance Computing and Communications Conference: IPCCC'11},
publisher = {IEEE Xplore},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--8},
type = {Konferenz-Beitrag},
month = {November},
year = {2011},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
C.2.2 Network Protocols,
C.2.3 Network Operations},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-84/INPROC-2011-84.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {The on-line processing of high volume data streams is a prerequisite for many
modern applications relying on real-time data such as global sensor networks or
multimedia streaming. In order to achieve efficient data processing and
scalability w.r.t. the number of distributed data sources and applications,
in-network processing of data streams in an overlay network of data processing
operators has been proposed. For such stream processing overlay networks, the
placement of operators onto physical hosts plays an important role for the
resulting quality of service—in particular, the endto- end latency—and network
load. To this end, we present an enhanced placement algorithm that minimizes
the network load put onto the system by a stream processing task under
userdefined delay constraints in this paper. Our algorithm finds first the
optimal solution in terms of network load and then degrades this solution to
find a constrained optimum. In order to reduce the overhead of the placement
algorithm, we included mechanisms to reduce the search space in terms of hosts
that are considered during operator placement. Our evaluations show that this
approach leads to an operator placement of high quality solution while inducing
communication overhead proportional only to a small percentage of the total
hosts.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-84&engl=0}
}
@inproceedings {INPROC-2011-74,
author = {Patrick Baier and Harald Weinschrott and Frank D{\"u}rr},
title = {{Effiziente automatisierte Erstellung von Stra{\ss}enkarten}},
booktitle = {7.GI/ITG KuVS-Fachgespr{\"a}ch. Ortsbezogene Anwendungen und Dienste.},
editor = {Roth J{\"o}rg K{\"u}pper Axel},
address = {Berlin},
publisher = {Logos Verlag Berlin GmbH},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {85--92},
type = {Konferenz-Beitrag},
month = {September},
year = {2011},
isbn = {978-3-8325-2935-2},
language = {Deutsch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.2 Network Protocols,
C.2.3 Network Operations,
C.2.4 Distributed Systems,
E.1 Data Structures},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-74/INPROC-2011-74.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Das relativ junge Paradigma des Urban Sensing erm{\"o}glicht die kosteng{\"u}nstige
Bereitstellung von Sensordaten, welche in diesem Umfang bisher nicht zug{\"a}nglich
waren. Ein potentieller Verwendungszweck dieser Daten liegt im Bereich der
Kartografie, indem von Mobilger{\"a}ten erfasste GPS-Daten genutzt werden, um
Stra{\ss}enkarten automatisch zu erstellen. Dadurch kann eine Ersparnis
hinsichtlich Aufwand und Kosten, im Vergleich zu konventionellen Methoden der
Kartenerstellung, erzielt werden. Diese Arbeit stellt einen solchen Ansatz zur
effizienten, automatisierten Erstellung von Stra{\ss}enkarten mithilfe von
GPS-Sensordaten vor. Diese Daten werden dabei automatisch von Personen
gesammelt, die ihre Mobilger{\"a}te wie gewohnt mit sich f{\"u}hren, zus{\"a}tzlich aber
auf ihren allt{\"a}glichen Wegen GPS-Positionsinformationen erfassen, welche sie
einem zentralen System zur Verf{\"u}gung stellen. Dies geschieht automatisch, ohne
dass eine Interaktion dieser Personen n{\"o}tig ist. Im Gegenzug soll der
Ressourcenverbrauch der teilnehmenden Mobilger{\"a}te m{\"o}glichst minimiert werden.
Daher koordiniert der in dieser Arbeit vorgestellte Ansatz die Erfassung der
GPS-Daten so, dass die Mobilger{\"a}te diese m{\"o}glichst nur dann erfassen, wenn sie
sich in einem Gebiet befinden, welches bis zu diesem Zeitpunkt noch nicht
ausreichend kartografisch erfasst wurde. Um diese gezielte Koordination der
Mobilger{\"a}te zu erm{\"o}glichen, werden im Rahmen dieser Arbeit Qualit{\"a}tsmetriken
f{\"u}r Geodaten vorgestellt, welche den erfassten Stra{\ss}en quantitative Gr{\"o}{\ss}en
zuordnen, um so einen Vergleich dieser Daten zu erm{\"o}glichen.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-74&engl=0}
}
@inproceedings {INPROC-2011-73,
author = {Damian Philipp and Frank D{\"u}rr and Kurt Rothermel},
title = {{A Sensor Network Abstraction for Flexible Public Sensing Systems}},
booktitle = {Proceedings of the 8th IEEE International Conference on Mobile Ad-Hoc and Sensor Systems: MASS'11; Valencia, Spain, October 17-22, 2011},
editor = {IEEE Computer Society Conference Publishing Services},
address = {Valencia},
publisher = {IEEE Computer Society Conference Publishing Services},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
series = {IEEE Computer Society Order Number},
volume = {E4469},
pages = {460--469},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2011},
doi = {10.1109/MASS.2011.52},
isbn = {978-0-7695-4469-4/11},
keywords = {Public Sensing; Sensor Networks; Smartphone},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.4 Distributed Systems,
C.2.5 Local and Wide-Area Networks,
C.5.3 Microcomputers},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-73/INPROC-2011-73.pdf,
http://dx.doi.org/10.1109/MASS.2011.52,
http://www.comnsense.de},
contact = {damian.philipp@ipvs.uni-stuttgart.de, frank.duerr@ipvs.uni-stuttgart.de, kurt.rothermel@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Public Sensing is a new paradigm for developing large-scale sensor networks at
low cost by utilizing mobile phones that are already surrounding us in our
everyday lives. In this paper we present a sensor network abstraction layer for
creating flexible public sensing systems that can execute arbitrary queries. To
this effect we develop several algorithms to select mobile nodes for executing
a query. These algorithms allow a user to define a trade-off between quality
and efficiency of query execution by choosing an appropriate algorithm. Our
evaluations show that we can achieve a 99$\backslash$\% increase in efficiency with the
most efficient approaches and only about 10$\backslash$\% decrease in result quality under
worst conditions.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-73&engl=0}
}
@inproceedings {INPROC-2011-61,
author = {Lars Geiger and Frank D{\"u}rr and Kurt Rothermel},
title = {{Adaptive Routing in a Contextcast Overlay Network}},
booktitle = {Proceedings of the IEEE 7th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob 2011)},
publisher = {IEEE Xplore},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--8},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2011},
doi = {10.1109/WiMOB.2011.6085340},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.2 Network Protocols,
C.2.4 Distributed Systems,
C.2.6 Internetworking},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-61/INPROC-2011-61.pdf,
http://dx.doi.org/10.1109/WiMOB.2011.6085340},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Context-based communication allows for the dissemination of messages to mobile
users with a specified context, i.e., at a location and with certain attribute
values. This enables, e.g., a message to students on campus attending a certain
class, with information about a study group for an upcoming exam. An overlay
network of context-aware routers efficiently disseminate the messages to all
matching receivers. Directed forwarding of such messages requires that the
routers maintain knowledge about the contexts of connected users. Global
knowledge, i.e., each router knowing about every user, scales poorly, though,
because of the necessary updates.
To overcome this challenge, a router can selectively propagate context
information that actually allows its neighbors to prune a message distribution
tree. In this paper, we present an approach to adaptively propagate only those
user contexts that offer a reduction in overall system load. The algorithm
automatically and locally adapts to the observed messages and user contexts on
each node.
Our solution significantly improves the scalability of the system by reducing
the overall load by almost 50\%.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-61&engl=0}
}
@inproceedings {INPROC-2011-59,
author = {Bilal Hameed and Jorge Minguez and Michael W{\"o}rner and Philip Hollstein and Sema Zor and Stefan Silcher and Frank D{\"u}rr and Kurt Rothermel},
title = {{The Smart Real-Time Factory as a Product Service System}},
booktitle = {3rd CIRP International Conference on Industrial Product Service Systems},
address = {Braunschweig, Germany},
publisher = {IRP},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--6},
type = {Konferenz-Beitrag},
month = {Januar},
year = {2011},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In modern manufacturing landscape, companies are increasingly relying on
product service systems i.e. bundling of products and services together in
order to gain a competitive edge. In this article we present the Smart
Real-Time Factory, a smart digital manufacturing environment that can transform
the process of production into an informational service for the customers. The
different components of the smart factory are discussed at length along with a
discussion of the different services that can be offered by the smart factory.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-59&engl=0}
}
@inproceedings {INPROC-2011-51,
author = {Patrick Baier and Harald Weinschrott and Frank D{\"u}rr and Kurt Rothermel},
title = {{MapCorrect: Automatic Correction and Validation of Road Maps Using Public Sensing}},
booktitle = {36th Annual IEEE Conference on Local Computer Networks (LCN 2011)},
address = {Bonn, Germany},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--8},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2011},
keywords = {ad-hoc; mobile; public sensing},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-51/INPROC-2011-51.pdf,
http://www.comnsense.de},
contact = {patrick.baier@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {With the increasing proliferation of small and cheap GPS receivers, a new way
of generating road maps could be witnessed over the last few years.
Participatory mapping approaches like OpenStreetMap, for instance, introduced a
way to generate road maps collaboratively from scratch. Nevertheless, one of
the main problems of these maps is their unknown quality in terms of accuracy.
To address this issue, we propose MapCorrect: An automatic map correction and
validation system. MapCorrect automatically collects GPS traces from people's
mobile devices to correct a given road map and validate it. Since the
collection of GPS data raises concerns about the energy consumption of the
participating mobile devices, we tackle this issue by introducing a selective
sensing mechanism. Furthermore, we show by simulation that using this approach
up to 50\% of energy on the mobile phones can be saved while not impairing the
map correction and validation process at all.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-51&engl=0}
}
@inproceedings {INPROC-2011-11,
author = {Frank D{\"u}rr and Pavel Skvortsov and Kurt Rothermel},
title = {{Position Sharing for Location Privacy in Non-trusted Systems}},
booktitle = {Proceedings of the 9th IEEE International Conference on Pervasive Computing and Communications (PerCom 2011)},
address = {Seattle, USA},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {189--196},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2011},
doi = {10.1109/PERCOM.2011.5767584},
keywords = {location-based service; privacy; obfuscation; sharing; location management},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
H.3.5 Online Information Services},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-11/INPROC-2011-11.pdf,
http://dx.doi.org/10.1109/PERCOM.2011.5767584,
http://www.priloc.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Many novel location-based services (LBS) such as a friend finder service
require knowledge about the positions of mobile users. Usually, location
services are used to manage these positions, and for providing basic
functionality like spatial range queries or spatial events to the LBS.
Managing and using the positions of mobile users raises privacy issues, in
particular, if the providers of LBS and location services are only partially
trusted. Many different approaches for preserving a user's privacy have been
proposed in the literature, e.g. location obfuscation and the k-anonymity
concept. However, most of them are not suitable if both LBS and location
service providers are non-trusted. In contrast to these approaches, we present
a novel approach for the secure management of private position information in
partially trusted system environments. The main contribution in this paper is a
position sharing concept which allows for the distribution of position
information (shares) of strictly limited accuracy onto several location servers
of different providers. With this approach, a compromised server will only
reveal information of limited accuracy. Moreover, we will show how position
shares of coarse granularity from multiple location servers can be fused into
information of higher precision to satisfy the accuracy requirements of
different LBS.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-11&engl=0}
}
@inproceedings {INPROC-2011-10,
author = {Harald Weinschrott and Julian Weisser and Frank D{\"u}rr and Kurt Rothermel},
title = {{Participatory Sensing Algorithms for Mobile Object Discovery in Urban Areas}},
booktitle = {Proceedings of the 9th Annual IEEE International Conference on Pervasive Computing and Communications},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {128--135},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2011},
doi = {10.1109/PERCOM.2011.5767577},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-10/INPROC-2011-10.pdf,
http://dx.doi.org/10.1109/PERCOM.2011.5767577,
http://www.comnsense.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {This paper introduces mechanisms for the automated detection of mobile objects
in urban areas. Widely available devices such as mobile phones with integrated
proximity sensors such as RFID readers or Bluetooth cooperatively perform
sensing operations to discover mobile objects. In this paper, we propose a
coverage metric for assessing the completeness of sensing that considers
spatial and temporal aspects. To maximize coverage while minimizing energy
consumption of mobile nodes, we propose both a centralized and a distributed
coordination algorithm for selecting nodes that need to sense. Moreover, we
present strategies that allow selected nodes to perform efficient sense
operations. By extensive simulations, we show that distributed coordination
achieves drastic energy savings of up to 63\%, while limiting the coverage loss
to 13\%. Moreover, we show that the centralized algorithm loses less than 1\%
coverage compared to the maximum possible coverage.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-10&engl=0}
}
@inproceedings {INPROC-2010-81,
author = {Ralph Lange and Frank D{\"u}rr and Kurt Rothermel},
title = {{Indexing Source Descriptions based on Defined Classes}},
booktitle = {Proceedings of the 14th International Database Engineering and Applications Symposium (IDEAS '10). Montreal, QC, Canada. August 2010},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {245--256},
type = {Konferenz-Beitrag},
month = {August},
year = {2010},
keywords = {heterogeneous information systems; source descriptions; indexing of source descriptions; defined classes; tree-based index structure},
language = {Englisch},
cr-category = {H.2.5 Heterogeneous Databases,
H.3.3 Information Search and Retrieval},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-81/INPROC-2010-81.pdf,
http://doi.acm.org/10.1145/1866480.1866514},
contact = {ralph.lange@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Scaling heterogeneous information systems (HIS) to thousands of sources poses
particular challenges to source discovery. It requires a powerful formalism for
describing the contents of the sources in a concise manner and for formulating
compatible queries as well as a suitable structure for indexing and retrieving
the source descriptions efficiently.
We propose an extended logic-based description formalism for large-scale HIS
with structured sources and a shared ontology. The formalism refines existing
approaches that describe the sources by constraints on the attribute value
ranges in several ways: It allows for complex, nested descriptions based on
defined classes. It supports alternative descriptions to express that a source
may be discovered by different combinations of constraints. Finally, it allows
to adjust between positive matching, similar to keyword-based discovery, and
negative matching, as used in existing logic-based approaches.
We further propose the SDC-Tree for indexing such source descriptions. To allow
for efficient discovery, the SDC-Tree features multidimensional indexing
capabilities for the different attributes and the IS-A hierarchy of the shared
ontology, but also incorporates the existence or absence of constraints. For
this purpose, it supports three different types of node split operations which
exploit the expressiveness of the description formalism. Therefore, we also
propose a generic split algorithm which can be used with arbitrary ontologies.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-81&engl=0}
}
@inproceedings {INPROC-2010-71,
author = {Bilal Hameed and Imran Ahmed Khan and Frank D{\"u}rr and Kurt Rothermel},
title = {{An RFID Based Consistency Management Framework for Production Monitoring In a Smart Real-Time Factory}},
booktitle = {Proceedings of 2010 Internet of Things Conference (To Appear).},
address = {Tokyo, Japan},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--8},
type = {Konferenz-Beitrag},
month = {November},
year = {2010},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks,
C.2.1 Network Architecture and Design},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {The use of RFID devices for real-time production monitoring in modern factories
is impeded by the inherent unreliability of RFID devices. In this paper we
present a consistency stack that conceptually divides the different consistency
issues in production monitoring into separate layers. In addition to this we
have built a consistency management framework to ensure consistent real-time
production monitoring, using unreliable RFID devices. In detail, we deal with
the problem of detecting object sequences by a set of unreliable RFID readers
that are installed along production lines. We propose a probabilistic sequence
detection algorithm that assigns probabilities to objects detected by RFID
devices and provides probabilistic guarantees regarding the real-time sequences
of objects on the production lines.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-71&engl=0}
}
@inproceedings {INPROC-2010-63,
author = {Harald Weinschrott and Frank D{\"u}rr and Kurt Rothermel},
title = {{StreamShaper: Coordination Algorithms for Participatory Mobile Urban Sensing}},
booktitle = {Proceedings of the 7th IEEE International Conference on Mobile Ad-hoc and Sensor Systems (MASS'10)},
address = {San Francisco, CA, USA},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {November},
year = {2010},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-63/INPROC-2010-63.pdf,
http://www.comnsense.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In this paper we introduce mechanisms for automated mapping of urban areas that
provide a virtual sensor abstraction to the applications. We envision a
participatory system that exploits widely available devices as mobile phones to
cooperatively read environmental conditions as air quality or noise pollution,
and map these measurements to stationary virtual sensors. We propose spatial
and temporal coverage metrics for measuring the quality of acquired sensor data
that reflect the conditions of urban areas and the uncontrolled movement of
nodes. To achieve quality requirements and efficiency in terms of energy
consumption, this paper presents two algorithms for coordinating sensing. The
first is based on a central control instance, which assigns sensing tasks to
mobile nodes based on movement predictions. The second algorithm is based on
coordination of mobile nodes in an ad-hoc network. By extensive simulations, we
show that these algorithms achieve a high quality of readings, which is about
95\% of the maximum possible. Moreover, the algorithms achieve a very high
energy efficiency allowing for drastic savings compared to uncoordinated
sensing.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-63&engl=0}
}
@inproceedings {INPROC-2010-60,
author = {Faraz Memon and Frank D{\"u}rr and Kurt Rothermel},
title = {{Index Recommendation Tool for Optimized Information Discovery Over Distributed Hash Tables}},
booktitle = {Proceedings of the 35th International Conference on Local Computer Networks (LCN '10)},
address = {Dever, CO, USA},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--8},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2010},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
E.1 Data Structures,
E.2 Data Storage Representations,
H.3.1 Content Analysis and Indexing},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-60/INPROC-2010-60.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Peer-to-peer (P2P) networks allow for efficient information discovery in
large-scale distributed systems. Although point queries are well supported by
current P2P systems -- in particular systems based on distributed hash tables
(DHTs) --, providing efficient support for more complex queries remains a
challenge. Our research focuses on the efficient support for multi-attribute
range (MAR) queries over DHT-based information discovery systems.
Traditionally, the support for MAR queries over DHTs has been provided either
by creating an individual index for each data attribute or by creating a single
index using the combination of all data attributes. In contrast to these
approaches, we propose to create a set of indices over selected attribute
combinations. In order to limit the overhead induced by index maintenance, the
total number of created indices has to be limited. Thus, the resulting problem
is to create a limited number of indices such that the overall system
performance is optimal for MAR queries. In this paper, we propose an index
recommendation tool that implements heuristic solutions to this NP-hard
problem. Our evaluations show that these heuristics lead to a close-to-optimal
system performance for MAR queries.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-60&engl=0}
}
@inproceedings {INPROC-2010-57,
author = {Stamatia Rizou and Frank D{\"u}rr and Kurt Rothermel},
title = {{Providing QoS Guarantees for Large-Scale Operator Networks}},
booktitle = {Proceedings of the 12th IEEE International Conference on High Performance Computing and Communications},
address = {Melbourne, VIC, Australia},
publisher = {IEEE Computer Society Press},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {337--345},
type = {Konferenz-Beitrag},
month = {September},
year = {2010},
doi = {10.1109/HPCC.2010.53},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-57/INPROC-2010-57.pdf,
http://dx.doi.org/10.1109/HPCC.2010.53},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Application areas like global sensor networks and data stream processing
involve the on-line processing of large amounts of data in an overlay network
of operators on top of the Internet infrastructure. Trying to fulfill QoS
guarantees in such networks is a challenging task that should be realized under
the requirement for optimal usage of common resources in the network. Therefore
in this paper, we formalize a constrained optimization problem for the
placement of operators in an overlay network which strives for satisfying user
QoS constraints subject to latency, while minimizing the network load induced
by the deployment of the operators in the network. Since the initial problem is
NP-hard, we solve at a first step the problem in an intermediate continuous
latency space and then we map the continuous solution to its discrete variant.
Our evaluations provide an analysis about the inherent interdepedence between
the two metrics, network usage and latency, subject to this paper and
furthermore shows that our algorithm achieves a good balance between the user
requirements and the usage of the network resources.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-57&engl=0}
}
@inproceedings {INPROC-2010-56,
author = {Stamatia Rizou and Frank D{\"u}rr and Kurt Rothermel},
title = {{Solving the Multi-operator Placement Problem in Large-Scale Operator Networks}},
booktitle = {Proceedings of the 19th International Conference on Computer Communication Networks},
address = {Zurich, Switzerland},
publisher = {IEEE Communications Society},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--6},
type = {Konferenz-Beitrag},
month = {August},
year = {2010},
doi = {10.1109/ICCCN.2010.5560127},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-56/INPROC-2010-56.pdf,
http://dx.doi.org/10.1109/ICCCN.2010.5560127},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Processing streams of data in an overlay network of operators distributed over
a wide-area network is a common idea shared by different applications such as
distributed event correlation systems and large-scale sensor networks. In order
to utilize network resources efficiently and allow for the parallel deployment
of a large number of large-scale operator networks, suitable placement
algorithms are vital that place operators on physical nodes. In this paper, we
present a distributed placement algorithm that minimizes the bandwidth-delay
product of data streams between operators of the network in order to reduce the
induced network load. Since the fundamental optimization problem is NP-hard, we
propose a heuristic solution. First, we calculate an optimal solution in an
intermediate continuous search space, called latency space. Subsequently the
continuous solution is mapped to the physical network. Our evaluations show
that this algorithm reduces the resulting network load significantly compared
to state of the art algorithms and achieves results close to the optimum.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-56&engl=0}
}
@inproceedings {INPROC-2010-43,
author = {Stamatia Rizou and Kai H{\"a}ussermann and Frank D{\"u}rr and Nazario Cipriani and Kurt Rothermel},
title = {{A system for distributed context reasoning.}},
booktitle = {Proceedings of ICAS’10: International Conference on Autonomous and Autonomic Systems},
publisher = {IEEE Computer Society Conference Publishing Services},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {84--89},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2010},
isbn = {978-0-7695-3970-6},
doi = {10.1109/ICAS.2010.21},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-43/INPROC-2010-43.pdf,
http://dx.doi.org/10.1109/ICAS.2010.21},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;
Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware},
abstract = {Context aware systems use context information to adapt their behaviour
accordingly. In order to derive high level context information from low level
context, such as sensor values, context reasoning methods that correlate
observable context information, are necessary. Several context reasoning
mechanisms have been proposed in the literature. Usually these mechanisms are
centralized, leading to suboptimal utilization of network resources and poor
system performance in case of large-scale scenarios. Therefore to increase the
scalability of context reasoning systems the development of methods that
distribute the reasoning process is necessary. Existing distributed approaches
are method specific and do not provide a generic formalization for distributed
reasoning. In this paper we introduce a novel system which enables distributed
context reasoning in a generic way that is independent of the reasoning
algorithm.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-43&engl=0}
}
@inproceedings {INPROC-2010-32,
author = {Lars Geiger and Frank D{\"u}rr and Kurt Rothermel},
title = {{Aggregation of User Contexts in Context-based Communication}},
booktitle = {Proceedings of the 6th Euro-NF Conference on Next Generation Internet (NGI 2010)},
address = {Paris},
publisher = {IEEE Xplore},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--8},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2010},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.2 Network Protocols,
C.2.4 Distributed Systems,
C.2.6 Internetworking},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-32/INPROC-2010-32.pdf,
http://dx.doi.org/10.1109/NGI.2010.5534466},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {A context-based communication system enables the indirect addressing and
routing of messages according to the users' contexts. This provides, for
example, the means to send a message to all students on campus who attend a
certain class, with information about an upcoming exam. However, for a targeted
forwarding of messages towards users, the routers need information about the
context of connected users. Global knowledge, i.e., each router knowing about
every user, is not scalable, though, because of the necessary update messages
to keep this information up-to-date.
To address this challenge, a router can aggregate similar contexts and only
provide such an aggregated view to neighboring routers. In this paper, we
present an approach to aggregate similar contexts, based on a similarity
measure for user contexts. The algorithm can be adjusted according to the
observed messages and user contexts in the system by specifying a similarity
threshold to determine when contexts are aggregated.
The aggregation of user contexts improves the scalability of our approach by
significantly reducing the load of context updates by up to 30\%, depending on
the usage of the system. This improvement comes at the cost of a negligible
increase in false positive messages due to the loss of information used for
forwarding messages.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-32&engl=0}
}
@inproceedings {INPROC-2010-17,
author = {Frank D{\"u}rr and Harald Weinschrott and Kurt Rothermel},
title = {{Geocast Routing of Symbolically Addressed Messages in Wireless Mesh Networks}},
booktitle = {Proceedings of the 8th IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom Workshops '10)},
address = {Mannheim, Germany},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {552--557},
type = {Workshop-Beitrag},
month = {M{\"a}rz},
year = {2010},
language = {Englisch},
cr-category = {C.2.2 Network Protocols},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-17/INPROC-2010-17.pdf,
http://dx.doi.org/10.1109/PERCOMW.2010.5470499},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Geocast protocols can be used to send messages to all receivers in a geographic
target area. In this paper we present geocast routing algorithms for Wireless
Mesh Networks that are tailored to symbolic addressing using symbolic location
names like floor or room numbers. Since in particular indoors no geometric
information is available, our algorithms use symbolic location models to derive
directional information for routing. Moreover, we show how to integrate
geometric and symbolic geographic routing algorithms into a hybrid routing
approach which is applicable to larger areas consisting of symbolically and
geometrically defined locations.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-17&engl=0}
}
@inproceedings {INPROC-2010-16,
author = {Harald Weinschrott and Frank D{\"u}rr and Kurt Rothermel},
title = {{Symbolic Routing for Location-based Services in Wireless Mesh Networks}},
booktitle = {Proceedings of the IEEE 24nd International Conference on Advanced Information Networking and Applications},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--8},
type = {Konferenz-Beitrag},
month = {April},
year = {2010},
language = {Englisch},
cr-category = {C.2.2 Network Protocols},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-16/INPROC-2010-16.pdf,
http://dx.doi.org/10.1109/AINA.2010.71},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Wireless Mesh Networks are cost-efficient medium-scale networks that have the
potential to serve as an infrastructure for advanced location-based services.
As a basis for these services we present a routing algorithm that allows to
address intuitive symbolic coordinates. This algorithm is based on a
proactively maintained geographic routing structure that mimics the structure
of a symbolic location model. Message forwarding is done greedily along short
paths defined by a symbolic location model and if this fails, through an
hierarchical overlay network built by selected mesh routers. We show how a
geocast communication mechanism that allows to send messages to all hosts
within a specific location can be implemented with this routing algorithm. In
extensive evaluations we show that a low proactive routing overhead allows to
achieve high message delivery rates even in case of mobility. Moreover, we show
that the paths achieved are only 25\% longer than the theoretic optimal paths
for a wide range of simulation settings.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-16&engl=0}
}
@inproceedings {INPROC-2010-15,
author = {Ralph Lange and Frank D{\"u}rr and Kurt Rothermel},
title = {{Efficient Tracking of Moving Objects using Generic Remote Trajectory Simplification (Demo Paper)}},
booktitle = {Proceedings of the 8th IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom Workshops '10). Mannheim, Germany. March 2010},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {829--831},
type = {Workshop-Beitrag},
month = {M{\"a}rz},
year = {2010},
keywords = {Remote trajectory simplification; tracking; dead reckoning; moving objects database; MOD; line simplification},
language = {Englisch},
cr-category = {H.2.8 Database Applications},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-15/INPROC-2010-15.pdf,
http://dx.doi.org/10.1109/PERCOMW.2010.5470553},
contact = {ralph.lange@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Position information of moving objects plays a vital role in many pervasive
applications. Therefore, moving objects databases (MODs), which can manage
trajectory data of a number objects, are used in many pervasive systems. A
crucial problem with MODs is how to efficiently track a remote object's
trajectory in real-time, i.e. how to continuously report the sensed trajectory
data to the MOD with minimal effort. For this purpose, we present a
prototypical implementation of the Generic Remote Trajectory Simplification
(GRTS) protocol, which optimizes storage consumption, processing, and
communication costs. Our prototypical system includes a fully functional MOD as
well as map-based mobile applications for subnotebooks and smartphones to
illustrate the functioning of GRTS.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-15&engl=0}
}
@inproceedings {INPROC-2010-118,
author = {Frank D{\"u}rr and Marius Wernke and Pavel Skvortsov and Kurt Rothermel},
title = {{Towards a Position Sharing Approach for Location-based Services}},
booktitle = {Proceedings of the W3C Workshop on Privacy for Advanced Web APIs},
publisher = {Online},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--3},
type = {Workshop-Beitrag},
month = {Juli},
year = {2010},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
H.3.5 Online Information Services},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-118/INPROC-2010-118.pdf,
http://www.w3.org/2010/api-privacy-ws/papers/privacy-ws-16.pdf,
http://www.priloc.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In partially-trusted system environments like the WWW, the management of
private user positions is a great challenge. On the one hand, location-based
services of different partially-trusted providers have to be provided with
position information. On the other hand, location servers, which are
responsible for the management of user positions, might as well be operated by
only partially-trusted providers. Therefore, in order to protect his privacy, a
user might only want to store position information of limited precision on
location servers, and also provide location-based services with position
information of limited precision.
In this position paper, we sketch a novel position sharing approach that
enables the user to tightly control the precision of position information
stored on servers and provided to location-based services. This approach is
based on the idea of distributing position information among a set of servers
of different providers such that a compromised server only reveals information
of strictly limited precision.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-118&engl=0}
}
@inproceedings {INPROC-2010-116,
author = {Faraz Memon and Daniel Tiebler and Frank D{\"u}rr and Kurt Rothermel},
title = {{Optimized Information Discovery using Self-adapting Indices over Distributed Hash Tables}},
booktitle = {Proceedings of 29th International Performance Computing and Communications Conference (IPCCC'10)},
address = {Albuquerque, New Mexico, USA},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--9},
type = {Konferenz-Beitrag},
month = {Dezember},
year = {2010},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
E.1 Data Structures,
E.2 Data Storage Representations,
H.3.1 Content Analysis and Indexing},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-116/INPROC-2010-116.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Distributed Hash Table (DHT)-based peer-to-peer information discovery systems
have emerged as highly scalable systems for information storage and discovery
in massively distributed networks. Originally DHTs supported only point
queries. However, recently they have been extended to support more complex
queries, such as multi-attribute range (MAR) queries. Generally, the support
for MAR queries over DHTs has been provided either by creating an individual
index for each data attribute or by creating a single index using the
combination of all data attributes. In contrast to these approaches, we propose
to create and modify indices using the attribute combinations that dynamically
appear in MAR queries in the system.
In this paper, we present an adaptive information discovery system that adapts
the set of indices according to the dynamic set of MAR queries in the system.
The main contribution of this paper is a four-phase scalable index adaptation
process. Our evaluations show that the adaptive information discovery system
continuously optimizes the overall system performance for MAR queries.
Moreover, compared to a non-adaptive system, the adaptive information discovery
system shows several orders of magnitude improved performance.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-116&engl=0}
}
@inproceedings {INPROC-2009-66,
author = {Lars Geiger and Ronald Schertle and Frank D{\"u}rr and Kurt Rothermel},
title = {{Temporal Addressing for Mobile Context-Aware Communication}},
booktitle = {Proceedings of the Sixth Annual International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services (MobiQuitous '09), Toronto, ON, Canada, July 13-16, 2009},
publisher = {ICST},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2009},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.2 Network Protocols,
C.2.4 Distributed Systems,
C.2.6 Internetworking},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-66/INPROC-2009-66.pdf,
http://www.ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5326393},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Mobile clients in context-aware systems benefit from the indirect addressing of
users via their context (contextcast), such as addressing messages to all users
in downtown Toronto whose age is below 35. There is, however, almost no support
for a temporal decoupling in such a contextcast system, i.e., the addressing of
users that were or will be in a certain context in the past or future,
respectively. This could for instance be used to distribute the minutes of a
meeting to all people who attended the meeting in room 1.138, 3 days ago,
between 1 and 3 pm.
To enable a context-aware communication system to address messages with
temporal relations, especially those contexts in the past, the system needs to
manage information about user context histories. This poses the risk that the
system can be abused to profile users, which would most probably hinder
acceptance. Therefore, privacy aspects need to be considered in the core design
of such a system. We present an extension to our earlier work, which allows a
temporal decoupling of messages and users and requires very little additional
overhead to manage historic context information. The solution includes
mechanisms to efficiently disseminate messages to both users with past and
future contexts, while effectively preventing user profiling through the use of
virtual identities.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-66&engl=0}
}
@inproceedings {INPROC-2009-51,
author = {Ralph Lange and Harald Weinschrott and Lars Geiger and Andre Blessing and Frank D{\"u}rr and Kurt Rothermel and Hinrich Sch{\"u}tze},
title = {{On a Generic Uncertainty Model for Position Information}},
booktitle = {Proceedings of the 1st International Workshop on Quality of Context},
publisher = {Springer},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--12},
type = {Workshop-Beitrag},
month = {Juni},
year = {2009},
keywords = {data uncertainty; position information; position accuracy; spatial queries},
language = {Englisch},
cr-category = {H.2.8 Database Applications},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-51/INPROC-2009-51.pdf,
http://www.springerlink.com/content/85450711831008k0/},
contact = {ralph.lange@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Maschinelle Sprachverarbeitung;
Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Position information of moving as well as stationary objects is generally
subject to uncertainties due to inherent measuring errors of positioning
technologies, explicit tolerances of position update protocols, and
approximations by interpolation algorithms. There exist a variety of approaches
for specifying these uncertainties by mathematical uncertainty models such as
tolerance regions or the Dilution of Precision (DOP) values of GPS. In this
paper we propose a principled generic uncertainty model that integrates the
different approaches and derive a comprehensive query interface for processing
spatial queries on uncertain position information of different sources based on
this model. Finally, we show how to implement our approach with prevalent
existing uncertainty models.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-51&engl=0}
}
@inproceedings {INPROC-2009-42,
author = {Faraz Memon and Daniel Tiebler and Frank D{\"u}rr and Kurt Rothermel and Marco Tomsu and Peter Domschitz},
title = {{Scalable Spatial Information Discovery over Distributed Hash Tables}},
booktitle = {Procs. of 4th International Conference on COMmunication System softWAre and middlewaRE (COMSWARE'09), Dublin, Ireland, June 2009. ACM.},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--12},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2009},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
H.3.3 Information Search and Retrieval},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-42/INPROC-2009-42.pdf,
http://doi.acm.org/10.1145/1621890.1621892},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In this paper, we present a Peer-to-Peer (P2P) spatial information discovery
system that enables spatial range queries over Distributed Hash Tables (DHTs).
Our system utilizes a less-distorting octahedral map projection in contrast to
the quadrilateral projections used by majority of the previously proposed
systems, to represent the spatial information. We also introduce a
Space-Filling Curve (SFC)-based data placement strategy that reduces the
probability of data hot-spots in the network. Moreover, we show that our system
achieves scalable resolution of location-based range queries by utilizing a
tree-based query optimization algorithm. Compared to the basic query resolution
algorithm, the query optimization algorithm reduces the average number of
parallel messages used to resolve a query, by a factor of 96\%.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-42&engl=0}
}
@inproceedings {INPROC-2009-32,
author = {Lars Geiger and Frank D{\"u}rr and Kurt Rothermel},
title = {{On Contextcast: A Context-aware Communication Mechanism}},
booktitle = {IEEE International Conference on Communications, 2009. ICC '09.},
publisher = {IEEE Communications Society},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--6},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2009},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.2 Network Protocols,
C.2.4 Distributed Systems,
C.2.6 Internetworking},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-32/INPROC-2009-32.pdf,
http://dx.doi.org/10.1109/ICC.2009.5199239},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {The dissemination of messages according to clients' contexts (i.e., location
and other attributes) opens up new possibilities in context-aware systems.
While geocast or content-based publish/subscribe forward messages according to
client location or attributes, respectively, neither uses a combination of the
two. In this paper, we present this new communication paradigm and the
challenges it poses. We also extend concepts from publish/subscribe networks to
efficiently deal with highly dynamic user location to lower update rates by
approximating the user's location. This reduces update rates by between 25\% and
90\%, depending on the granularity of the approximation.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-32&engl=0}
}
@inproceedings {INPROC-2009-24,
author = {Harald Weinschrott and Frank D{\"u}rr and Kurt Rothermel},
title = {{Efficient Capturing of Environmental Data with Mobile RFID Readers}},
booktitle = {Proceedings of the 10th International Conference on Mobile Data Management (MDM'09); Taipei, Taiwan, Mai 18-20, 2009},
address = {Taipei, Taiwan},
publisher = {IEEE Computer Society Conference Publishing Services},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {Mai},
year = {2009},
keywords = {ad-hoc; mobile; RFID-sensor; urban sensing},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-24/INPROC-2009-24.pdf,
http://doi.ieeecomputersociety.org/10.1109/MDM.2009.15,
http://www.comnsense.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In this paper we introduce a novel scenario for environmental sensing based on
the combination of simple and cheap RFID-based sensors and mobile devices like
mobile phones with integrated RFID readers. We envision a system, where the
mobile nodes cooperatively read sensors installed in the environment as they
pass by and transmit the data to a server infrastructure. To achieve quality
requirements on the one hand, and on the other hand efficiency in terms of
communication cost and energy consumption, this paper presents several
algorithms for coordinating update operations. Mobile nodes form an ad-hoc
network for the cooperative management of requested update times to meet the
desired update interval and to avoid redundant sensor reading and collisions
during read operations. Besides this decentralized coordination algorithm, we
also show a complementary algorithm that exploits infrastructure based
coordination. By extensive simulations we show that our algorithms achieve a
high quality of sensor updates where nearly 100\% of the possible updates are
performed. Moreover, the algorithms achieve a very high energy efficiency
allowing for several hundred hours of operation assuming a typical battery of a
mobile phone.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-24&engl=0}
}
@inproceedings {INPROC-2009-06,
author = {Ralph Lange and Tobias Farrell and Frank D{\"u}rr and Kurt Rothermel},
title = {{Remote Real-Time Trajectory Simplification}},
booktitle = {Proceedings of the 7th Annual IEEE International Conference on Pervasive Computing and Communications (PerCom '09). Galveston, TX, USA. March 2009},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2009},
keywords = {Remote trajectory simplification; tracking; dead reckoning; moving objects database; MOD; line simplification},
language = {Englisch},
cr-category = {H.2.8 Database Applications},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-06/INPROC-2009-06.pdf,
http://dx.doi.org/10.1109/PERCOM.2009.4912767},
contact = {ralph.lange@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Moving objects databases (MODs) have been proposed for managing trajectory
data, an important kind of information for pervasive applications. To save
storage capacity, a MOD generally stores simplified trajectories only. A
simplified trajectory approximates the actual trajectory of the mobile object
according to a certain accuracy bound. In order to minimize the costs of
communicating position information between mobile object and MOD, the
trajectory simplification should be performed by the mobile object. To assure
that the MOD always has a valid simplified trajectory of the remote object, we
propose the generic remote trajectory simplification protocol (GRTS) allowing
for computing and managing a simplified trajectory in such a system in
real-time. We show how to combine GRTS with existing line simplification
algorithms for computing the simplified trajectory and analyze trade-offs
between the different algorithms. Our evaluations show that GRTS outperforms
the two existing approaches by a factor of two and more in terms of reduction
efficiency. Moreover, on average, the reduction efficiency of GRTS is only 12\%
worse compared to optimal offline simplification.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-06&engl=0}
}
@inproceedings {INPROC-2008-84,
author = {Ralph Lange and Frank D{\"u}rr and Kurt Rothermel},
title = {{Scalable Processing of Trajectory-Based Queries in Space-Partitioned Moving Objects Databases}},
booktitle = {Proceedings of the 16th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems (ACM GIS 2008)},
address = {Irvine, CA, USA},
publisher = {ACM},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {November},
year = {2008},
keywords = {spatio-temporal indexing; moving objects database; MOD; trajectory-based query; distributed query processing},
language = {Englisch},
cr-category = {H.2.8 Database Applications},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-84/INPROC-2008-84.pdf,
http://doi.acm.org/10.1145/1463434.1463474},
contact = {ralph.lange@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Space-partitioned Moving Objects Databases (SP-MODs) allow for the scalable,
distributed management of large sets of mobile objects' trajectories by
partitioning the trajectory data to a network of database servers. Processing a
spatio-temporal query q therefore requires efficiently routing q to the servers
storing the affected trajectory segments. With a coordinate-based query - like
a spatio-temporal range query - the relevant servers are directly determined by
the queried range. However, with trajectory-based queries - like retrieving the
distance covered by a certain object during a given time interval - the
relevant servers depend on actual movement of the queried object. Therefore,
efficient routing mechanisms for trajectory-based queries are an important
challenge in SP-MODs. In this paper, we present the Distributed Trajectory
Index (DTI) that allows for such efficient query routing by creating an overlay
network for each trajectory. We further present an enhanced index called DTI+S.
It accelerates the processing of queries on aggregates of dynamic attributes,
like the maximum speed during a time interval, by augmenting DTI with summaries
of trajectory segments. Our simulations with a network of 1000 database servers
show that DTI+S can reduce the overall processing time by more than 98\%.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-84&engl=0}
}
@inproceedings {INPROC-2008-83,
author = {Faraz Memon and Daniel Tiebler and Frank D{\"u}rr and Kurt Rothermel and Marco Tomsu and Peter Domschitz},
title = {{OID: Optimized Information Discovery using Space Filling Curves in P2P Overlay Networks}},
booktitle = {Proceedings of 14th International Conference on Parallel and Distributed Systems (ICPADS'08)},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {311--319},
type = {Konferenz-Beitrag},
month = {Dezember},
year = {2008},
isbn = {978-0-7695-3434-3},
language = {Englisch},
cr-category = {C.2.2 Network Protocols,
C.2.3 Network Operations,
C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-83/INPROC-2008-83.pdf,
http://dx.doi.org/10.1109/ICPADS.2008.57},
contact = {faraz.memon@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In this paper, we present the system design and evaluation of a Space-Filling
Curve (SFC)-based P2P information discovery system OID. The OID system uses
multiple SFCs to significantly optimize the performance of multi-attribute
range queries, particularly for applications with a large number of data
attributes where a single big SFC-based index is inefficient. The basic idea is
to have multiple SFCbased indices and select the best one to perform a query.
We also introduce two tree-based query optimizations that increase the
scalability of the system.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-83&engl=0}
}
@inproceedings {INPROC-2008-37,
author = {Ralph Lange and Frank D{\"u}rr and Kurt Rothermel},
title = {{Online Trajectory Data Reduction using Connection-preserving Dead Reckoning}},
booktitle = {Proceedings of the Fifth Annual International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services: MobiQuitous '08; Dublin, Ireland, July 21-25, 2008},
publisher = {ICST},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {Juli},
year = {2008},
isbn = {978-963-9799-21-9},
keywords = {Online trajectory reduction; dead reckoning; MOD},
language = {Englisch},
cr-category = {H.2.8 Database Applications},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-37/INPROC-2008-37.pdf,
http://portal.acm.org/citation.cfm?id=1595044},
contact = {ralph.lange@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Moving objects databases (MODs) store objects’ trajectories by spatiotemporal
polylines that approximate the actual movements given by sequences of sensed
positions. Determining such a polyline with as few vertices as possible under
the constraint that it does not deviate by more than a certain accuracy bound
epsilon from the sensed positions is an algorithmic problem known as trajectory
reduction.
A specific challenge is online trajectory reduction, i.e. continuous reduction
with position sensing in realtime. This particularly is required for moving
objects with embedded position sensors whose movements are tracked and stored
by a remote MOD.
In this paper, we present Connection-preserving Dead Reckoning (CDR), a new
approach for online trajectory reduction. It outperforms the existing
approaches by 30 to 50\%. CDR requires the moving objects to temporally store
some of the previously sensed positions. Although the storage consumption of
CDR generally is small, it is not bounded. We therefore further present CDRM
whose storage allocation and execution time per position fix can be adjusted
and limited. Even with very limited storage allocations of less than 1 kB CDRM
outperforms the existing approach by 20 to 40\%.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-37&engl=0}
}
@inproceedings {INPROC-2008-113,
author = {Frank D{\"u}rr and Kurt Rothermel},
title = {{Kommunikationsprotokolle zur Vermittlung kontextbezogener Informationen auf Basis r{\"a}umlicher Umgebungsmodelle}},
booktitle = {Proceedings of VDE-Kongress 2008 -- Zukunftstechnologien: Innovationen - M{\"a}rkte - Nachwuchs},
address = {Munich, Germany},
publisher = {VDE Verlag GmbH},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {1--6},
type = {Konferenz-Beitrag},
month = {November},
year = {2008},
isbn = {978-3-8007-3126-8},
keywords = {contextcast; geocast; Protokoll; protocol; kommunikation; communication; location-based; context-aware; ortsbezogen; kontextbezogen; Ort; Kontext; lokationsbasiert; service; Dienst},
language = {Deutsch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-113/INPROC-2008-113.pdf,
http://www.vde-verlag.de/proceedings-en/453126101.html},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In diesem Artikel stellen wir ein neuartiges kontextbezogenes
Kommunikationsparadigma namens Contextcast vor. Contextcast erm{\"o}glicht das
selektive Senden von Nachrichten an Teilnehmer mit einem bestimmten Kontext,
wobei der Kontext eines Teilnehmers beispielsweise durch seinen Aufenthaltsort,
seine Interessen oder seine Situation bestimmt ist. Typische Anwendungen f{\"u}r
Contextcast sind die gezielte Verteilung von Warnmeldungen,
Touristeninformationen oder Veranstaltungshinweise. Wir pr{\"a}sentieren zun{\"a}chst
Konzepte zur effizienten Vermittlung von ortsbezogenen Informationen (Geocast)
und diskutieren anschlie{\ss}end notwendige Erweiterungen f{\"u}r die effiziente
Realisierung der Contextcast-Kommunikation.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-113&engl=0}
}
@inproceedings {INPROC-2008-110,
author = {Frank D{\"u}rr and Jonas Palauro and Lars Geiger and Ralph Lange and Kurt Rothermel},
title = {{Ein kontextbezogener Instant-Messaging-Dienst auf Basis des XMPP-Protokolls}},
booktitle = {5. GI/ITG KuVS Fachgespr{\"a}ch Ortsbezogene Anwendungen und Dienste. N{\"u}rnberg. September 2008},
address = {N{\"u}rnberg},
publisher = {Georg-Simon-Ohm-Hochschule N{\"u}rnberg},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
series = {Sonderdruck Schriftenreihe der Georg-Simon-Ohm-Hochschule N{\"u}rnberg},
volume = {42},
pages = {23--28},
type = {Workshop-Beitrag},
month = {September},
year = {2008},
issn = {1867-5433},
keywords = {Nexus; Instant-Messaging; Kontextbezug; context-awareness; Contextcast; XMPP},
language = {Deutsch},
cr-category = {H.4.3 Information Systems Applications Communications Applications},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-110/INPROC-2008-110.pdf,
http://www.nexus.uni-stuttgart.de/,
http://www.wireless-earth.de/fg_lbs/meeting_5/meeting_5.html},
contact = {frank.duerr@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Dieser Beitrag beschreibt die Verteilung kontextbezogener Informationen mittels
eines erweiterten Instant-Messaging-Dienstes. Dieser Dienst erm{\"o}glicht das
Senden von Nachrichten an alle Teilnehmer, die einen bestimmten Kontext
besitzen und sich z.B. an einem bestimmten Ort aufhalten oder bestimmte
Interessen besitzen. Als Basis dient das Extensible Messaging and Presence
Protokoll (XMPP) sowie ein XMPP-basierter Instant-Messaging-Dienst. Wir
beschreiben Protokoll- und Architekturerweiterungen f{\"u}r die Integration von
Kontextinformationen in das XMPP-Protokoll und die Server-Infrastruktur. Der
erweiterte Dienst unterst{\"u}tzt insbesondere die Server-seitige Filterung von
Nachrichten aufgrund von Kontextinformationen und erm{\"o}glicht dadurch die
effiziente Nachrichtenverteilung.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-110&engl=0}
}
@inproceedings {INPROC-2008-03,
author = {Frank D{\"u}rr and Kurt Rothermel},
title = {{An Adaptive Overlay Network for World-wide Geographic Messaging}},
booktitle = {Proceedings of the 22nd IEEE International Conference on Advanced Information Networking and Applications (AINA 2008); Gino-wan, Okinawa, Japan, March 25-28, 2008},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {875--882},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2008},
keywords = {geocast; overlay network; communication; protocol; location-based service; geographic communication; networking; context; context-aware systems},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-03/INPROC-2008-03.pdf,
http://dx.doi.org/10.1109/AINA.2008.67},
contact = {frank.duerr@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In this paper, we propose an overlay network supporting world-wide geographic
messaging. Our approach is based on hierarchical symbolic coordinates like
/usa/fl/miami/. Although hierarchical network topologies lend themselves to the
implementation of such overlay networks, they may lead to bottlenecks at the
root of the hierarchy, long message paths, and inefficient bandwidth
utilization. To avoid these problems, we propose an overlay network that adapts
its structure to the users' communication patterns by dynamically adding
shortcut`` links to the hierarchy leading to a routing mesh. We present an
algorithm that carefully selects shortcuts based on their utility to assure
short message paths on the one hand and to reduce the induced overhead on the
other hand. Through simulations we show that this approach decreases the
average path length significantly and reduces network load to about 50\%
compared to hierarchical routing.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-03&engl=0}
}
@inproceedings {INPROC-2007-38,
author = {Lars Geiger and Frank D{\"u}rr},
title = {{Kontextbezogene Kommunikation}},
booktitle = {4. GI/ITG KuVS Fachgespr{\"a}ch Ortsbezogene Anwendungen und Dienste},
editor = {J{\"o}rg Roth and Axel K{\"u}pper and Claudia Linnhoff-Popien},
address = {M{\"u}nchen},
publisher = {Verlag Dr. Hut},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {22--26},
type = {Konferenz-Beitrag},
month = {September},
year = {2007},
isbn = {978-3-89963-591-1},
keywords = {Kontext; Kommunikation; Multicast; Nexus},
language = {Deutsch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.2 Network Protocols,
C.2.4 Distributed Systems,
C.2.6 Internetworking},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-38/INPROC-2007-38.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Verbindet man die Position eines Benutzers mit weiteren Attributen wie
beispielsweise Typ, Alter oder Status zu seinem Kontext, so ergeben sich daraus
interessante neue Anwendungsm{\"o}glichkeiten. In diesem Artikel soll ein Verfahren
vorgestellt werden, wie ein solcher Kontext benutzt werden kann, um Nachrichten
an bestimmte Gruppen von Benutzern --- bestimmt durch ihren Kontext --- zu
versenden. Ein solcher Kommunikationsmechanismus k{\"o}nnte beispielsweise
eingesetzt werden, um Verkehrsnachrichten gezielt an alle Fahrzeuge innerhalb
eines bestimmten Gebietes und mit einer bestimmten Fahrtrichtung zu
{\"u}bermitteln.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-38&engl=0}
}
@inproceedings {INPROC-2007-15,
author = {Martin Saternus and Mirko Knoll and Frank D{\"u}rr and Torben Weis},
title = {{Symstry: Ein P2P-System f{\"u}r Ortsbezogene Anwendungen}},
booktitle = {Proceedings of 15. ITG/GI - Fachtagung (KiVS 2007)},
publisher = {VDE-Verlag},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {99--104},
type = {Konferenz-Beitrag},
month = {Februar},
year = {2007},
isbn = {ISBN 978-3-8007-2980-7},
keywords = {peer-to-peer; context-aware system},
language = {Deutsch},
cr-category = {H.3.3 Information Search and Retrieval},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-15&engl=0}
}
@inproceedings {INPROC-2007-14,
author = {Martin Saternus and Torben Weis and Mirko Knoll and Frank D{\"u}rr},
title = {{A Middleware for Context-Aware Applications and Services Based on Messenger Protocols}},
booktitle = {Proceedings of the Fifth Annual IEEE International Conference on Pervasive Computing and Communications Workshops (PerComW'07)},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {467--471},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2007},
keywords = {context-aware application; middleware; user interface; messenger},
language = {Englisch},
cr-category = {D.2.6 Software Engineering Programming Environments,
H.5.0 Information Interfaces and Presentation General},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Nowadays most context-aware applications are independent proprietary pieces of
software. A general framework or middleware deployed in the field does not
exist; therefore the implementation of context-aware applications and services
assumes the development of the whole application stack for each application.
Along these development issues, deployment and privacy problems are to be
solved.
This imposes the following challenges concerning a middleware for context-aware
applications: (1) We need an architecture that allows to implement and deploy
services easily on the network. (2) We need a user interface that is
widespread, well known to users and allows to mange one’s privacy settings for
every single service transparently.
In this paper we describe our middleware’s architecture for context-aware
applications, based on messenger protocols.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-14&engl=0}
}
@inproceedings {INPROC-2006-51,
author = {Frank D{\"u}rr and Kurt Rothermel},
title = {{An Overlay Network for Forwarding Symbolically Addressed Geocast Messages}},
booktitle = {Proceedings of the 15th International Conference on Computer Communications and Networks (ICCCN '06); Arlington, VA, October 9-11, 2006},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {427--434},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2006},
isbn = {0-4244-0572-6},
keywords = {network protocols; communication protocols; geocast; location-based services},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-51/INPROC-2006-51.pdf,
http://dx.doi.org/10.1109/ICCCN.2006.286314},
contact = {frank.duerr@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Geocast, which allows for forwarding messages to hosts residing at specified
geographic areas, is a promising communication paradigm with a wide range of
applications. Geocast target areas can be specified either by geometric figures
or symbolic addresses, such as /usa/fl/miami/market-street.
In this paper, we present a novel geocast routing protocol for symbolically
addressed messages. Compared to geocast protocols based on geometric
information, our protocol can operate on simple symbolic location models, and
message forwarding does not require costly geometric operations. The proposed
protocol is based on an overlay network that is mapped to an IP-based network
infrastructure. The overlay network is structured in a hierarchical fashion, to
ensure a scalable global geocast service supporting also large target areas.
Although our protocol does not rely on a layer 3 multicast protocol, we also
show how to improve the performance of message forwarding by integrating a
light-weight layer 3 multicast protocol. Our evaluations of the protocol
underline the scalability of our approach and show good routing quality leading
to short message paths.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-51&engl=0}
}
@inproceedings {INPROC-2006-06,
author = {Matthias Wieland and Frank Leymann and Lamine Jendoubi and Daniela Nicklas and Frank D{\"u}rr},
title = {{Task-orientierte Anwendungen in einer Smart Factory}},
booktitle = {Mobile Informationssysteme - Potentiale, Hindernisse, Einsatz. Proceedings MMS´06},
editor = {Thomas Kirste and Birgitta K{\"o}nig-Ries and Key Pousttchi and Klaus Turowski},
address = {Bonn},
publisher = {Gesellschaft f{\"u}r Informatik},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
series = {Lecture Notes in Informatics (LNI)},
volume = {P-76},
pages = {139--143},
type = {Konferenz-Beitrag},
month = {Februar},
year = {2006},
isbn = {3-88579-170-6},
keywords = {Kontextbezogene Applikationen; Smart Factory; kontextbezogene Workflows},
language = {Deutsch},
cr-category = {H.4.2 Information Systems Applications Types of Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-06/INPROC-2006-06.pdf,
http://www.nexus.uni-stuttgart.de/},
contact = {Matthias Wieland wieland@informatik.uni-stuttgart.de, Daniela Nicklas nicklas@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware;
Universit{\"a}t Stuttgart, Institut f{\"u}r Industrielle Fertigung und Fabrikbetrieb (IFF);
Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen;
Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In diesem Beitrag wird aufgezeigt, welche M{\"o}glichkeiten sich durch den Einsatz
task-orientierter, explorativer Anwendungen im Umfeld einer Smart Factory
ergeben. Nach einer kurzen Charakterisierung dieser Anwendungsklasse wird ein
Szenario geschildert, das Wartungsaufgaben in einer Fabrik mit diesen Konzepten
l{\"o}st. Daraus ergibt sich die Vision einer Smart Factory, in der die
Gesch{\"a}ftsprozesse {\"u}ber ein Kontextmodell mit den technischen Prozessen der
Produktionsstra{\ss}e gekoppelt werden.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-06&engl=0}
}
@inproceedings {INPROC-2005-31,
author = {Frank D{\"u}rr and Christian Becker and Kurt Rothermel},
title = {{Efficient Forwarding of Symbolically Addressed Geocast Messages}},
booktitle = {Proceedings of the 14th International Conference on Computer Communications an Networks (ICCCN 2005); San Diego, CA, October 2005},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {77--85},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2005},
doi = {10.1109/ICCCN.2005.1523812},
keywords = {Geocast, Multicast, Networking, Communication Network, Location-based Service},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-31/INPROC-2005-31.pdf,
http://dx.doi.org/10.1109/ICCCN.2005.1523812},
contact = {frank.duerr@informatik.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Geocast is used to send messages to all hosts located in a geographic area.
This target area can be defined either by geometric figures like polygons or by
symbolic addresses like city names or room numbers.
Geographic routing algorithms, which forward messages based on geographic
information, can be used to forward geocast messages. If routing of
symbolically addressed messages is based on geometric coordinates, complex
mappings between symbolic addresses and their geometric extent as well as
complex geometric operations are required. Therefore, we propose a routing
algorithm for symbolically addressed geocast messages that operates directly on
a symbolic location model. This approach does not require any geometric
information for message forwarding, and forwarding decisions can be realized
efficiently by comparably simple operations.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-31&engl=0}
}
@inproceedings {INPROC-2004-53,
author = {Kurt Rothermel and Frank D{\"u}rr},
title = {{Location-based Services: Auf dem Weg zu kontextbezogenen Informations- und Kommunikationssystemen}},
booktitle = {Zukunft durch Informationstechnik - Schnell-Mobil-Intelligent -- Jubil{\"a}umsfachtagung 50 Jahre ITG},
editor = {VDE},
address = {Frankfurt, Germany},
publisher = {VDE Verlag GmbH},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
pages = {121--128},
type = {Konferenz-Beitrag},
month = {April},
year = {2004},
isbn = {3-8007-2825-7},
keywords = {Location-based Services; Geocast; Hoarding; Context-aware Systems; Context-aware Computing},
language = {Deutsch},
cr-category = {H.3.4 Information Storage and Retrieval Systems and Software,
C.2.2 Network Protocols,
H.2.8 Database Applications},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2004-53/INPROC-2004-53.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Die rasant fortschreitende Entwicklung von drahtloser Kommunikation,
Positionierungssystemen und Rechnertechnologie sowie deren Integration in
multifunktionale Endger{\"a}te unterst{\"u}tzt die vielversprechende neue
Anwendungsklasse der ortsbezogenen Systeme. Ortsinformation kann von solchen
Anwendungen genutzt werden, um ihr Verhalten dem aktuellen Standort der
Benutzer oder auch anderer Objekte anzupassen. Heute schon bieten Netzbetreiber
so genannte ``Location-based Services'' an, die prim{\"a}r Navigationsfunktionen und
eine ortsbezogene Selektion von Informationen unterst{\"u}tzen. Ortsinformation
kann aber auch auf der Systemebene gewinnbringend verwendet werden, etwa zur
Bereitstellung neuer ortsbezogener Kommunikationskonzepte oder zur Optimierung
der Kommunikation.
In diesem Beitrag wird der Begriff der ortsbezogene Anwendungen erl{\"a}utert und
Anwendungen dieser Art am Beispiel existierender Systeme kurz skizziert.
Au{\ss}erdem werden zwei Beispiele f{\"u}r die Nutzung von Ortsinformation auf
Systemebene gegeben, die Geocast-Kommunikation und ein Hoarding-Verfahren.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-53&engl=0}
}
@inproceedings {INPROC-2004-29,
author = {Frank D{\"u}rr and Nicola H{\"o}nle and Daniela Nicklas and Christian Becker and Kurt Rothermel},
title = {{Nexus--A Platform for Context-Aware Applications}},
booktitle = {1. GI/ITG Fachgespr{\"a}ch Ortsbezogene Anwendungen und Dienste.},
editor = {J{\"o}rg Roth},
address = {Hagen},
publisher = {FernUniversit{\"a}t in Hagen},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
series = {Informatik-Berichte der FernUniversit{\"a}t in Hagen},
volume = {317},
pages = {15--18},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2004},
keywords = {Location-based Service; Context-aware System; Platform; Geocast},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
H.2.4 Database Management Systems,
H.2.8 Database Applications,
H.3.4 Information Storage and Retrieval Systems and Software,
C.2.2 Network Protocols},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2004-29/INPROC-2004-29.pdf},
contact = {Senden Sie eine E-Mail an frank.duerr@informatik.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;
Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware},
abstract = {In this paper we present the Nexus Platform for context-aware applications.
This platform allows to share the effort of setting up a global and detailed
context model between different providers by federating their partial models.
Applications can query data directly, use push-based communication through an
event service, or use value-added services like a navigation or map service for
special tasks. Additional context-aware services like hoarding or geocast can
be implemented on basis of the platform. For the latter we present different
approaches for addressing and efficient message forwarding based on the Nexus
Platform.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-29&engl=0}
}
@inproceedings {INPROC-2003-24,
author = {Frank D{\"u}rr and Kurt Rothermel},
title = {{On a Location Model for Fine-Grained Geocast}},
booktitle = {UbiComp 2003: Ubiquitous Computing (Proceedings of the Fifth International Conference on Ubiquitous Computing 2003); Seattle, WA, October 2003},
editor = {Anind K. Dey and Albrecht Schmidt and Joseph F. McCarthy},
publisher = {Springer-Verlag},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
series = {Lecture Notes in Computer Science},
volume = {2864},
pages = {18--35},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2003},
isbn = {3-540-20301-X},
keywords = {Ubiquitous Computing; Location Model; Geocast},
language = {Englisch},
cr-category = {C.2.2 Network Protocols},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-24/INPROC-2003-24.pdf,
http://www.springerlink.com/content/e9apt8y1w5nmem89/},
contact = {frank.duerr@informatik.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Geographic communication (geocast) is used to send messages to geographic
areas, e.g. to distribute warning messages or other information within these
areas. It is based on a location model which is used to determine a message's
target area and the receivers' positions and therefore has strong influence on
the achievable granularity of geographic addressing.
A hybrid location model and and a fine-grained addressing scheme for geocast
based on this model are presented in this paper which support two- and
three-dimensional geometric locations as well as symbolic locations like room
numbers, embedded local coordinate systems, and mobile target areas like
trains.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-24&engl=0}
}
@inproceedings {INPROC-2003-20,
author = {Kurt Rothermel and Dominique Dudkowski and Frank D{\"u}rr and Martin Bauer and Christian Becker},
title = {{Ubiquitous Computing - More than Computing Anytime Anyplace?}},
booktitle = {Proceedings of the 49. Photogrammetrische Woche},
address = {Stuttgart},
publisher = {ifp},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
type = {Konferenz-Beitrag},
month = {September},
year = {2003},
keywords = {Kontext; kontextbezogene Systeme; Ubiquitous Computing; Nexus},
language = {Deutsch},
cr-category = {H.2.8 Database Applications,
H.3.4 Information Storage and Retrieval Systems and Software},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-20/INPROC-2003-20.pdf,
http://www.nexus.uni-stuttgart.de},
contact = {Kurt.Rothermel@informatik.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {The rapid development of mobile communication networks and the availability of
miniaturized and inexpensive sensor technology allow for the development of
multifunctional mobile devices that are able to collect and communicate context
information. We also currently see a clear trend towards the integration of
embedded systems including sensors into {\ss}mart`` everyday things, which is also
referred to as Ubiquitous Computing. The deployment of sensor technology allows
for so-called context-aware applications, going far beyond of providing mobile
access to information and computing resources. Context-aware applications
exploit captured sensor information to adapt to the current situation of mobile
users. For instance, the information offered to a user may depend on his
current location, and the way how it is presented to him may depend on the
speed he moves, whether he is on its own or with others, and so on.
In this paper, we characterize context-aware applications and present the
vision of a digital world model as the foundation for this class of
applications. Further, the paper discusses the benefits and reseach challenges
associated with digital world models, which allow applications to take into
account the state of the real world and react to state changes.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-20&engl=0}
}
@inproceedings {INPROC-2002-08,
author = {Peter Coschurba and Kurt Rothermel and Frank D{\"u}rr},
title = {{A fine grained addressing concept for GeoCast}},
booktitle = {Trends in Network and Pervasive Computing -- ARCS 2002 (Proceedings of the International Conference on Architecture of Computing Systems 2002)},
editor = {Hartmut Schmeck and Theo Unger and Lars Wolf},
address = {Karlsruhe, Germany},
publisher = {Springer-Verlag},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
series = {Lecture Notes in Computer Science},
volume = {2299},
pages = {101--113},
type = {Konferenz-Beitrag},
month = {April},
year = {2002},
isbn = {3-540-43409-7},
keywords = {routing; location-based services; geographic communication; GeoCast},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2002-08/INPROC-2002-08.pdf,
http://www.springerlink.com/content/8hcep0e11k61tx53/},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {GeoCast provides the functionality of sending messages to everyone in a
specific area. So far, only the addressing of larger two-dimensional areas was
possible. For the use in an urban environment it is crucial that small and
three-dimensional areas can be addressed. For example, GeoCast can then be used
to send lecture notes to all in a classroom. In this paper we describe a
fine-grained addressing concept for GeoCast that supports such areas. In
addition we present an architecture that allows the use of that addressing
concept together with the GeoRouting-approach developed by Navas and
Imielinski. We also present some modifications necessary to enhance the
scalability of GeoCast.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-08&engl=0}
}
@article {ART-2022-05,
author = {Jonathan Falk and Heiko Geppert and Frank D{\"u}rr and Sukanya Bhowmik and Kurt Rothermel},
title = {{Dynamic QoS-Aware Traffic Planning for Time-Triggered Flows in the Real-time Data Plane}},
journal = {IEEE Transactions on Network and Service Management},
publisher = {IEEE},
volume = {19},
number = {2},
pages = {1807--1825},
type = {Artikel in Zeitschrift},
month = {Juni},
year = {2022},
isbn = {10.1109/TNSM.2022.3150664},
keywords = {traffic planning, QoS, reconfiguration, time-triggered},
language = {Deutsch},
cr-category = {C.2.3 Network Operations,
C.2.5 Local and Wide-Area Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2022-05/ART-2022-05.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Many networked applications, e.g., in the domain of cyber-physical systems,
require strict service guarantees for time-triggered traffic flows, usually in
the form of jitter and latency bounds. It is a notoriously hard problem to
compute a network-wide traffic plan, i.e., a set of routes and transmission
schedules, that satisfies these requirements, and dynamic changes in the flow
set add even more challenges. Existing traffic-planning methods are ill-suited
for dynamic scenarios because they either suffer from high computational cost,
can result in low network utilization, or provide no explicit guarantees when
transitioning to a new traffic plan that incorporates new flows.
Therefore, we present a novel approach for dynamic traffic planning of
time-triggered flows. Our conflict-graph-based modeling of the traffic planning
problem allows for the reconfiguration of active flows to increase the network
utilization, while also providing per-flow QoS guarantees during the transition
to the new traffic plan. Additionally, we introduce a novel heuristic for
computing the new traffic plans. Evaluations of our prototypical implementation
show that we can efficiently compute new traffic plans in scenarios with
hundreds of active flows for a wide range of settings.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2022-05&engl=0}
}
@article {ART-2022-04,
author = {Jonathan Falk and Heiko Geppert and Frank D{\"u}rr and Sukanya Bhowmik and Kurt Rothermel},
title = {{Dynamic QoS-Aware Traffic Planning for Time-Triggered Flows in the Real-time Data Plane}},
journal = {IEEE Transactions on Network and Service Management},
publisher = {IEEE},
volume = {19},
number = {2},
pages = {1807--1825},
type = {Artikel in Zeitschrift},
month = {Juni},
year = {2022},
isbn = {10.1109/TNSM.2022.3150664},
keywords = {traffic planning, QoS, reconfiguration, time-triggered},
language = {Deutsch},
cr-category = {C.2.3 Network Operations,
C.2.5 Local and Wide-Area Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2022-04/ART-2022-04.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Many networked applications, e.g., in the domain of cyber-physical systems,
require strict service guarantees for time-triggered traffic flows, usually in
the form of jitter and latency bounds. It is a notoriously hard problem to
compute a network-wide traffic plan, i.e., a set of routes and transmission
schedules, that satisfies these requirements, and dynamic changes in the flow
set add even more challenges. Existing traffic-planning methods are ill-suited
for dynamic scenarios because they either suffer from high computational cost,
can result in low network utilization, or provide no explicit guarantees when
transitioning to a new traffic plan that incorporates new flows.
Therefore, we present a novel approach for dynamic traffic planning of
time-triggered flows. Our conflict-graph-based modeling of the traffic planning
problem allows for the reconfiguration of active flows to increase the network
utilization, while also providing per-flow QoS guarantees during the transition
to the new traffic plan. Additionally, we introduce a novel heuristic for
computing the new traffic plans. Evaluations of our prototypical implementation
show that we can efficiently compute new traffic plans in scenarios with
hundreds of active flows for a wide range of settings.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2022-04&engl=0}
}
@article {ART-2022-03,
author = {Jonathan Falk and Heiko Geppert and Frank D{\"u}rr and Sukanya Bhowmik and Kurt Rothermel},
title = {{Dynamic QoS-Aware Traffic Planning for Time-Triggered Flows in the Real-time Data Plane}},
journal = {IEEE Transactions on Network and Service Management},
publisher = {IEEE},
volume = {19},
number = {2},
pages = {1807--1825},
type = {Artikel in Zeitschrift},
month = {Juni},
year = {2022},
isbn = {10.1109/TNSM.2022.3150664},
keywords = {traffic planning, QoS, reconfiguration, time-triggered},
language = {Deutsch},
cr-category = {C.2.3 Network Operations,
C.2.5 Local and Wide-Area Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2022-03/ART-2022-03.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Many networked applications, e.g., in the domain of cyber-physical systems,
require strict service guarantees for time-triggered traffic flows, usually in
the form of jitter and latency bounds. It is a notoriously hard problem to
compute a network-wide traffic plan, i.e., a set of routes and transmission
schedules, that satisfies these requirements, and dynamic changes in the flow
set add even more challenges. Existing traffic-planning methods are ill-suited
for dynamic scenarios because they either suffer from high computational cost,
can result in low network utilization, or provide no explicit guarantees when
transitioning to a new traffic plan that incorporates new flows.
Therefore, we present a novel approach for dynamic traffic planning of
time-triggered flows. Our conflict-graph-based modeling of the traffic planning
problem allows for the reconfiguration of active flows to increase the network
utilization, while also providing per-flow QoS guarantees during the transition
to the new traffic plan. Additionally, we introduce a novel heuristic for
computing the new traffic plans. Evaluations of our prototypical implementation
show that we can efficiently compute new traffic plans in scenarios with
hundreds of active flows for a wide range of settings.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2022-03&engl=0}
}
@article {ART-2022-02,
author = {Jonathan Falk and Heiko Geppert and Frank D{\"u}rr and Sukanya Bhowmik and Kurt Rothermel},
title = {{Dynamic QoS-Aware Traffic Planning for Time-Triggered Flows in the Real-time Data Plane}},
journal = {IEEE Transactions on Network and Service Management},
publisher = {IEEE},
volume = {19},
number = {2},
pages = {1807--1825},
type = {Artikel in Zeitschrift},
month = {Juni},
year = {2022},
isbn = {10.1109/TNSM.2022.3150664},
keywords = {traffic planning, QoS, reconfiguration, time-triggered},
language = {Deutsch},
cr-category = {C.2.3 Network Operations,
C.2.5 Local and Wide-Area Networks},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2022-02/ART-2022-02.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Many networked applications, e.g., in the domain of cyber-physical systems,
require strict service guarantees for time-triggered traffic flows, usually in
the form of jitter and latency bounds. It is a notoriously hard problem to
compute a network-wide traffic plan, i.e., a set of routes and transmission
schedules, that satisfies these requirements, and dynamic changes in the flow
set add even more challenges. Existing traffic-planning methods are ill-suited
for dynamic scenarios because they either suffer from high computational cost,
can result in low network utilization, or provide no explicit guarantees when
transitioning to a new traffic plan that incorporates new flows.
Therefore, we present a novel approach for dynamic traffic planning of
time-triggered flows. Our conflict-graph-based modeling of the traffic planning
problem allows for the reconfiguration of active flows to increase the network
utilization, while also providing per-flow QoS guarantees during the transition
to the new traffic plan. Additionally, we introduce a novel heuristic for
computing the new traffic plans. Evaluations of our prototypical implementation
show that we can efficiently compute new traffic plans in scenarios with
hundreds of active flows for a wide range of settings.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2022-02&engl=0}
}
@article {ART-2021-02,
author = {Otto Bibartiu and Frank D{\"u}rr and Kurt Rothermel and Beate Ottenw{\"a}lder and Andreas Grau},
title = {{Scalable k-out-of-n models for dependability analysis with Bayesian networks}},
journal = {Reliability Engineering \& System Safety},
editor = {Paolo Gardoni},
publisher = {Elsevier Science Ltd.},
volume = {210},
pages = {1--13},
type = {Artikel in Zeitschrift},
month = {Februar},
year = {2021},
isbn = {10.1016/S0951-8320(21)00145-9},
keywords = {Availability; Scalability; Voting Gate; Fault-Tree; Bayesian networks},
language = {Englisch},
cr-category = {B.8.1 Reliability, Testing, and Fault-Tolerance,
C.4 Performance of Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2021-02/ART-2021-02.pdf,
https://doi.org/10.1016/j.ress.2021.107533},
contact = {otto.bibartiu@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Availability analysis is indispensable in evaluating the dependability of
safety and business-critical systems, for which fault tree analysis (FTA) has
proven very useful throughout research and industry. Fault trees (FT) can be
analyzed by means of a rich set of mathematical models. One particular model
are Bayesian networks (BNs) which have gained considerable popularity recently
due to their powerful inference abilities. However, large-scale systems, as
found in modern data centers for cloud computing, pose modeling challenges that
require scalable availability models. An equivalent BN of a FT has no scalable
representation for the k-out-of-n (k/n) voting gate because the conditional
probability table that constitutes the k/n voting gate grows exponentially in
n. Thus, the memory becomes the limiting factor. We propose a scalable k/n
voting gate representation for BNs, based on the temporal noisy adder. The
resulting model reduces the initial exponential to polynomial memory growth
without a custom inference algorithm. Previous BN implementations of the k/n
voting gate could only handle around 30 input events until memory limits make
inference infeasible. However, our evaluation shows that our scalable model can
handle more than 700 input events per gate, making it possible to evaluate
large scale systems.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2021-02&engl=0}
}
@article {ART-2018-10,
author = {Thomas Kohler and Frank D{\"u}rr and Kurt Rothermel},
title = {{ZeroSDN: A Highly Flexible and Modular Architecture for Full-range Distribution of Event-based Network Control}},
journal = {IEEE Transactions on Network and Service Management},
editor = {Wolfgang Kellerer},
publisher = {IEEE Communications Society},
pages = {1--14},
type = {Artikel in Zeitschrift},
month = {Januar},
year = {2018},
keywords = {Software-defined Networking; OpenFlow; Control Plane Distribution; Publish/Subscribe; White-box Networking; Virtualization},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.4 Distributed Systems,
C.2.3 Network Operations},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2018-10/ART-2018-10.pdf},
contact = {thomas.kohler@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2018-10&engl=0}
}
@article {ART-2018-01,
author = {Christoph Dibak and Bernard Haasdonk and Andreas Schmidt and Frank D{\"u}rr and Kurt Rothermel},
title = {{Enabling Interactive Mobile Simulations Through Distributed Reduced Models}},
journal = {Pervasive and Mobile Computing},
publisher = {Elsevier BV},
pages = {1--26},
type = {Artikel in Zeitschrift},
month = {Februar},
year = {2018},
doi = {10.1016/j.pmcj.2018.02.002},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2018-01&engl=0}
}
@article {ART-2016-24,
author = {Sukanya Bhowmik and Muhammad Adnan Tariq and Boris Koldehofe and Frank D{\"u}rr and Thomas Kohler and Kurt Rothermel},
title = {{High Performance Publish/Subscribe Middleware in Software-Defined Networks}},
journal = {IEEE/ACM Transactions on Networking},
publisher = {IEEE},
volume = {25},
number = {3},
pages = {1--16},
type = {Artikel in Zeitschrift},
month = {Dezember},
year = {2016},
isbn = {10.1109/TNET.2016.2632970},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2016-24/ART-2016-24.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2016-24&engl=0}
}
@article {ART-2016-07,
author = {Thomas Kohler and Frank D{\"u}rr and Kurt Rothermel},
title = {{Consistent Network Management for Software-defined Networking based Multicast}},
journal = {IEEE Transactions on Network and Service Management},
editor = {Rolf Stadler},
publisher = {IEEE Communications Society},
pages = {1--1},
type = {Artikel in Zeitschrift},
month = {September},
year = {2016},
isbn = {10.1109/TNSM.2016.2585672},
keywords = {Software-defined networking, configuration management, update consistency, quality-of-service management, multicast communication},
language = {Englisch},
cr-category = {C.2.1 Network Architecture and Design,
C.2.3 Network Operations,
C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2016-07/ART-2016-07.pdf,
http://dx.doi.org/10.1109/TNSM.2016.2585672},
contact = {thomas.kohler@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Updating a network is an essential and continual task in the management of
today{\^a}€™s softwarized networks. When applying updates on distributed network
elements, desired network properties, such as drop- and loop-freeness, might be
transiently violated. Although being crucial, update consistency has yet been
less considered in network management.
In this article, we argue for incorporating the particularities of update
consistency into the reconfiguration process of continuous network management.
We present a generic management architecture allowing for an appropriate
selection of an update mechanism and its parameters based on expected
inconsistency effects. We investigate update consistency for the case of
multicast routing and show in an extensive analysis why simultaneous drop- and
duplicate-freeness is not possible. We present an update procedure for
multicast routing updates that identifies critical update steps, which are fed
back into the reconfiguration process, along with a lightweight approach that
allows for the selection of an update strategy, preventing either drops or
duplicates. Furthermore, we present an optimization of an existing powerful,
but resource-intensive update approach as well as an approach for in-network
filtering of duplicates.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2016-07&engl=0}
}
@article {ART-2014-03,
author = {Marius Wernke and Pavel Skvortsov and Frank D{\"u}rr and Kurt Rothermel},
title = {{A Classification of Location Privacy Attacks and Approaches}},
journal = {Personal and Ubiquitous Computing (Special Issue on Security and Trust in Context-Aware Systems)},
publisher = {Springer London},
volume = {18},
number = {1},
pages = {163--175},
type = {Artikel in Zeitschrift},
month = {Januar},
year = {2014},
issn = {1617-4909},
doi = {10.1007/s00779-012-0633-z},
keywords = {location-based services; location privacy; adversary; attack; classification; location privacy approaches},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
H.3.5 Online Information Services},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2014-03/ART-2014-03.pdf,
http://link.springer.com/article/10.1007%2Fs00779-012-0633-z,
http://www.priloc.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {In recent years, location-based services have become very popular, mainly
driven by the availability of modern mobile devices with integrated position
sensors. Prominent examples are points of interest finders or geo-social
networks like Facebook Places, Qype, Loopt. Because these services access
private position information, location privacy concepts become mandatory in
order to ensure that users accept these services.
Many different concepts and approaches for the protection of location privacy
have been described in the literature. These approaches differ with respect to
the protected information and their effectiveness against different attacks.
The goal of this paper is to assess the applicability and effectiveness of
location privacy approaches systematically. We first identify different
protection goals, namely, personal information (user identity), spatial
information (user position), and temporal information (identity/position +
time). Secondly, we give an overview of basic principles and existing
approaches to protect these privacy goals. In a third step, we classify
possible attacks. Finally, we analyzed existing approaches with respect to
their protection goals and their ability to resists the introduced attacks.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2014-03&engl=0}
}
@article {ART-2013-02,
author = {Marius Wernke and Frank D{\"u}rr and Kurt Rothermel},
title = {{PShare: Ensuring location privacy in non-trusted systems through multi-secret sharing}},
journal = {Pervasive and Mobile Computing},
publisher = {Elsevier},
pages = {1--17},
type = {Artikel in Zeitschrift},
month = {Februar},
year = {2013},
doi = {10.1016/j.pmcj.2013.01.001},
keywords = {Location-based applications; Privacy; Position sharing; Location management},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2013-02/ART-2013-02.pdf,
http://www.priloc.de,
http://dx.doi.org/10.1016/j.pmcj.2013.01.001},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Location-based applications such as Facebook Places, Foursquare, or Loopt
typically use location services to manage mobile object positions. However,
exposing precise user positions raises user privacy concerns, especially if
location service providers are not fully trusted. To enable the secure
management of private user positions in non-trusted systems, we present two
novel position sharing approaches based on the concept of multi-secret sharing.
We improve existing geometric position sharing approaches [1, 2] by considering
continuous position updates and by increasing the robustness against various
attacks. Furthermore, we present the first position sharing approach for
symbolic location models.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2013-02&engl=0}
}
@article {ART-2012-18,
author = {Kurt Rothermel and Stephan Schnitzer and Ralph Lange and Frank D{\"u}rr and Tobias Farrell},
title = {{Context-aware and quality-aware algorithms for efficient mobile object management}},
journal = {Pervasive and Mobile Computing},
publisher = {Elsevier},
volume = {8},
number = {1},
pages = {131--146},
type = {Artikel in Zeitschrift},
month = {Februar},
year = {2012},
doi = {10.1016/j.pmcj.2011.04.009},
issn = {1574-1192},
keywords = {context-awareness; location management; mobile object tracking; range queries; efficiency},
language = {Englisch},
cr-category = {C.2 Computer-Communication Networks,
H.2.8 Database Applications},
ee = {http://dx.doi.org/10.1016/j.pmcj.2011.04.009},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {The management of positions of mobile objects is an essential prerequisite for
many context-aware systems such as advanced traffic management systems or
personal assistance systems. In this paper, we present two approaches for the
scalable tracking of mobile object trajectories and the efficient processing of
continuous spatial range queries, respectively. We show in detail how both
approaches utilize the basic concepts of accuracy relaxation and utilization of
context information, such as movement predictions, to minimize the number of
position updates, the size of trajectory data, and the number of
energy-consuming position sensing operations.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2012-18&engl=0}
}
@article {ART-2011-11,
author = {Ralph Lange and Frank D{\"u}rr and Kurt Rothermel},
title = {{Efficient real-time trajectory tracking}},
journal = {The VLDB Journal},
publisher = {Springer Berlin Heidelberg},
volume = {20},
number = {5},
pages = {671--694},
type = {Artikel in Zeitschrift},
month = {Oktober},
year = {2011},
doi = {10.1007/s00778-011-0237-7},
issn = {1066-8888},
keywords = {moving objects database; MOD; trajectory tracking; dead reckoning; line simplification},
language = {Englisch},
cr-category = {H.2.8 Database Applications},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2011-11/ART-2011-11.pdf,
http://dx.doi.org/10.1007/s00778-011-0237-7},
contact = {ralph.lange@ipvs.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Moving objects databases (MOD) manage trajectory information of vehicles,
animals, and other mobile objects. A crucial problem is how to efficiently
track an object's trajectory in real-time, in particular if the trajectory data
is sensed at the mobile object and thus has to be communicated over a wireless
network. We propose a family of tracking protocols that allow trading the
communication cost and the amount of trajectory data stored at a MOD off
against the spatial accuracy. With each of these protocols, the MOD manages a
simplified trajectory that does not deviate by more than a certain accuracy
bound from the actual movement. Moreover, the different protocols enable
several trade-offs between computational costs, communication cost, and the
reduction in the trajectory data: Connection-Preserving Dead Reckoning
minimizes the communication cost using dead reckoning, a technique originally
designed for tracking an object's current position. Generic Remote Trajectory
Simplification (GRTS) further separates between tracking of the current
position and simplification of the past trajectory and can be realized with
different line simplification algorithms. For both protocols, we discuss how to
bound the space consumption and computing time at the moving object and thereby
present an effective compression technique to optimize the reduction
performance of real-time line simplification in general. Our evaluations with
hundreds of real GPS traces show that a realization of GRTS with a simple
simplification heuristic reaches 85-90\% of the best possible reduction rate,
given by retrospective offline simplification. A realization with the optimal
line simplification algorithm by Imai and Iri even reaches more than 97\% of the
best possible reduction rate.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2011-11&engl=0}
}
@article {ART-2006-20,
author = {Christian Becker and Frank D{\"u}rr and Mirko Knoll and Daniela Nicklas and Torben Weis},
title = {{Entwicklung ortsbezogener Anwendungen}},
journal = {Praxis der Informationsverarbeitung und Kommunikation (PIK)},
editor = {Hans G. Kruse},
publisher = {K. G. Saur Verlag},
volume = {29},
number = {1},
pages = {30--36},
type = {Artikel in Zeitschrift},
month = {Januar},
year = {2006},
doi = {10.1515/PIKO.2006.30},
keywords = {ortsbezogene Dienste; Anwendungsentwicklung},
language = {Deutsch},
cr-category = {D.2.2 Software Engineering Design Tools and Techniques},
contact = {Torben Weis torben.weis@informatik.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;
Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware},
abstract = {Ortsbezogene Anwendungen versorgen Benutzer mit Diensten und Informationen in
Abh{\"a}ngigkeit ihrer aktuellen Position. Beispiele sind im Bereich der
Telematikdienste, Touristenf{\"u}hrer und Informationsdienste zu finden.
Anwendungen k{\"o}nnen sich an den Ort oder ganz allgemein an den Kontext des
Benutzers anpassen, indem sie ortsspezifische Informationen anzeigen oder Daten
der jeweiligen Situation entsprechend pr{\"a}sentieren. Es existieren verschieden
Ans{\"a}tze und Architekturen, um ortsbezogene Anwendungen zu realisieren. In
diesem Beitrag stellen wir unterschiedliche Ans{\"a}tze vor, diskutieren deren Vor-
und Nachteile und leiten daraus ein abstraktes Anwendungsmodell f{\"u}r
ortsbezogene Anwendungen ab. Des Weiteren stellen wir Entwicklungswerkzeuge
vor, die wir auf Basis dieses Anwendungsmodells konzipiert haben. Die
Kombination aus Anwendungsmodell und spezialisierten Werkzeugen wird die
Entwicklung ortsbezogener Anwendungen systematisieren und wesentlich
vereinfachen.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2006-20&engl=0}
}
@article {ART-2005-19,
author = {Christian Becker and Frank D{\"u}rr},
title = {{On Location Models for Ubiquitous Computing}},
journal = {Personal and Ubiquitous Computing},
publisher = {Springer-Verlag},
volume = {9},
number = {1},
pages = {20--31},
type = {Artikel in Zeitschrift},
month = {Januar},
year = {2005},
keywords = {Location Model; Umgebungsmodell, Ubiquitous Computing; Context-aware Computing; Location-based Services},
language = {Englisch},
cr-category = {H.0 Information Systems General},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2005-19/ART-2005-19.pdf,
http://www.springerlink.com/content/7qjyl3g9hly15ky2/},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
abstract = {Common queries regarding information processing in ubiquitous computing are
based on the location of physical objects. No matter if the next printer, next
restaurant, or friend is searched for, a notion of distances between objects is
required. A search for all objects in a certain geographic area requires the
possibility to define spatial ranges and spatial inclusion of locations. In
this paper we discuss general properties of symbolic and geometric coordinates.
Based on that, we present an overview of existing location models allowing for
position, range, and nearest neighbor queries. The location models are
classified according to their suitability with respect to the query processing
and the involved modeling effort along with other requirements. Besides an
overview of existing location models and approaches the classification of
location models with respect to application requirements can assist developers
in their design decisions.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2005-19&engl=0}
}
@proceedings {PROC-2009-02,
editor = {Kurt Rothermel and Dieter Fritsch and Wolfgang Blochinger and Frank D{\"u}rr},
title = {{Quality of Context -- Proceedings of the First International Workshop on Quality of Context (QuaCon 2009)}},
address = {Stuttgart, Germany},
publisher = {Springer},
institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
series = {Lecture Notes in Computer Science},
volume = {5786},
pages = {184},
type = {Tagungsband},
month = {Juni},
year = {2009},
isbn = {978-3-642-04558-5},
keywords = {context-aware systems; location-based services; quality; context},
language = {Englisch},
cr-category = {H.2.8 Database Applications,
H.3.3 Information Search and Retrieval,
H.3.5 Online Information Services},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware;
Universit{\"a}t Stuttgart, Institut f{\"u}r Photogrammetrie (ifp);
Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;
Universit{\"a}t Stuttgart, Institut f{\"u}r Maschinelle Sprachverarbeitung},
abstract = {Advances in sensor technology, wireless communication, and mobile devices lead
to the proliferation of sensors in our physical environment. At the same time
detailed digital models of buildings, towns, or even the globe become widely
available. Integrating the huge amount of sensor data into spatial models
results in highly dynamic models of the real world, often called context
models.
A wide range of applications can substantially benefit from context models.
However, context data are inherently associated with uncertainty. In general,
quality of context information has to be taken into account by both context
management and applications. For example, the accuracy, completeness, and
trustworthiness of spatial context information such as street or building data
are very important for navigation and guidance systems.
QuaCon 2009 was the first international scientific meeting that specifically
focused on the different aspects of quality of context data. Research in
context management and, in particular, context quality, requires an
interdisciplinary approach. Therefore, the QuaCon workshop aimed to bring
together researchers from various fields to discuss approaches to context
quality and to make a consolidated contribution toward an integrated way of
treating this topic. We received 19 high-quality paper submissions by
researchers from Europe, USA, and Asia. The International Program Committee
selected 11 papers for presentation at the workshop. Additionally, five invited
contributions by internationally renowned experts in the field were included in
the workshop program. The presentations at the workshop showed many facets of
quality of context from different research fields including context data
management, spatial models, context reasoning, privacy, and system frameworks.
The lively discussions underlined the great interest in this topic and in
particular led to a deeper understanding of the relations between the various
aspects of quality of context.
The success of QuaCon 2009 was the result of a team effort. We are grateful to
the members of the Program Committee and the external reviewers for their
thorough and timely reviews as well as to the authors for their high-quality
submissions and interesting talks. We would like to extend special thanks to
our invited speakers for their excellent and inspiring keynotes. Finally, we
wish to thank all persons involved in the organization of the QuaCon 2009
workshop who did really a great job.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=PROC-2009-02&engl=0}
}