@inproceedings {INPROC-2016-38,
author = {Andreas Wei{\ss} and Vasilios Andrikopoulos and Santiago G{\'o}mez S{\'a}ez and Michael Hahn and Dimka Karastoyanova},
title = {{ChorSystem: A Message-Based System for the Life Cycle Management of Choreographies}},
booktitle = {On the Move to Meaningful Internet Systems: OTM 2016 Conferences: Confederated International Conferences: CoopIS, C\&TC, and ODBASE 2016, Rhodes, Greece, October 24-28, 2016, Proceedings},
editor = {Christophe Debruyne and Herv{\'e} Panetto and Robert Meersman and Tharam Dillon and Eva K{\"u}hn and Declan O'Sullivan and Claudio Agostino Ardagna},
publisher = {Springer International Publishing},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {503--521},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2016},
doi = {10.1007/978-3-319-48472-3_30},
keywords = {Collaborative Dynamic Complex (CDC) Systems; Choreography Life Cycle Management; Flexible Choreographies},
language = {Englisch},
cr-category = {H.4.1 Office Automation},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-38/INPROC-2016-38.pdf},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Service choreographies are commonly used as the means for enabling
inter-organizational collaboration by providing a global view on the message
exchange between involved participants. Choreographies are ideal for a number
of application domains that are classi ed under the Collaborative, Dynamic \&
Complex (CDC) systems area. System users in these application domains require
facilities to control the execution of a choreography instance such as
suspending, resuming or terminating, and thus actively control its life cycle.
We support this requirement by introducing the ChorSystem, a system capable of
managing the complete life cycle of choreographies from choreography modeling,
through deployment, to execution and monitoring. The performance evaluation of
the life cycle operations shows that the ChorSystem introduces an acceptable
performance overhead compared to purely script-based scenarios, while gaining
the abilities to control the choreography life cycle.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-38&engl=0}
}
@inproceedings {INPROC-2016-27,
author = {K{\'a}lm{\'a}n K{\'e}pes and Uwe Breitenb{\"u}cher and Santiago G{\'o}mez S{\'a}ez and Jasmin Guth and Frank Leymann and Matthias Wieland},
title = {{Situation-Aware Execution and Dynamic Adaptation of Traditional Workflow Models}},
booktitle = {Proceedings of the 5th European Conference on Service-Oriented and Cloud Computing (ESOCC)},
publisher = {Springer International Publishing},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
series = {LNCS},
volume = {9846},
pages = {69--83},
type = {Konferenz-Beitrag},
month = {September},
year = {2016},
doi = {10.1007/978-3-319-44482-6_5},
language = {Englisch},
cr-category = {H.4.1 Office Automation},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The continuous growth of the Internet of Things together with the complexity of
modern information systems results in several challenges for modeling,
provisioning, executing, and maintaining systems that are capable of adapting
themselves to changing situations in dynamic environments. The properties of
the workflow technology, such as its recovery features, makes this technology
suitable to be leveraged in such environments. However, the realization of
situation-aware mechanisms that dynamically adapt process executions to
changing situations is not trivial and error prone, since workflow modelers
cannot reflect all possibly occurring situations in complex environments in
their workflow models. In this paper, we present a method and concepts to
enable modelers to create traditional, situation-independent workflow models
that are automatically transformed into situation-aware workflow models that
cope with dynamic contextual situations. Our work builds upon the usage of
workflow fragments, which are dynamically selected during runtime to cope with
prevailing situations retrieved from low-level context sensor data. We validate
the practical feasibility of our work by a prototypical implementation of a
Situation-aware Workflow Management System (SaWMS) that supports the presented
concepts.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-27&engl=0}
}
@inproceedings {INPROC-2016-15,
author = {David Richard Sch{\"a}fer and Andreas Wei{\ss} and Muhammad Adnan Tariq and Vasilios Andrikopoulos and Santiago G{\'o}mez S{\'a}ez and Lukas Krawczyk and Kurt Rothermel},
title = {{HAWKS: A System for Highly Available Executions of Workflows}},
booktitle = {Proceedings of the 13th IEEE International Conference on Services Computing: SCC'16; San Francisco, California, USA, June 27-July 2, 2016},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {130--137},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2016},
doi = {10.1109/SCC.2016.24},
keywords = {SOA; workflows; availability; replication; performance},
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-2016-15/INPROC-2016-15.pdf,
http://dx.doi.org/10.1109/SCC.2016.24},
department = {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 = {The workflow technology is the de facto standard for managing business
processes. Today, workflows are even used for automating interactions and
collaborations between business partners, e.g., for enabling just-in-time
production. Every workflow that is part of such a collaboration needs to be
highly available. Otherwise, the business operations, e.g., the production,
might be hindered or even stopped. Since today's business partners are
scattered across the globe, the workflows are executed in a highly distributed
and heterogeneous environment. Those environments are, however, failure-prone
and, thus, providing availability is not trivial. In this work, we improve
availability by replicating workflow executions, while ensuring that the
outcome is the same as in a non-replicated execution. For making workflow
replication easily usable with current workflow technology, we derive the
requirements for modeling a workflow replication system. Then, we propose the
HAWKS system, which adheres to the previously specified requirements and is
compatible with current technology. We implement a proof-of-concept in the
open-source workflow execution engine Apache ODE for demonstrating this
compatibility. Finally, we extensively evaluate the impact of using HAWKS in
terms of performance and availability in the presence of failures.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-15&engl=0}
}
@inproceedings {INPROC-2016-02,
author = {Vasilios Andrikopoulos and Marina Bitsaki and Santiago G{\'o}mez S{\'a}ez and Michael Hahn and Dimka Karastoyanova and Giorgios Koutras and Alina Psycharaki},
title = {{Evaluating the Effect of Utility-based Decision Making in Collective Adaptive Systems}},
booktitle = {Proceedings of the 6th International Conference on Cloud Computing and Service Science (CLOSER 2016)},
address = {Rome, Italy},
publisher = {SciTePress},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--10},
type = {Konferenz-Beitrag},
month = {April},
year = {2016},
language = {Deutsch},
cr-category = {D.2.0 Software Engineering General,
D.2.11 Software Engineering Software Architectures,
D.2.12 Software Engineering Interoperability},
contact = {Vasilios Andrikopoulos: andrikopoulos@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Utility, defined as the perceived satisfaction with a service, provides the
ideal means for decision making on the level of individual entities and
collectives participating in a large-scale dynamic system. Previous works have
already introduced the concept into the area of collective adaptive systems,
and have discussed what is the necessary infrastructure to support the
realization of the involved theoretical concepts into actual decision making.
In this work we focus on two aspects. First, we provide a concrete utility
model for a case study that is part of a larger research project. Second, we
incorporate this model into our implementation of the proposed architecture.
More importantly, we design and execute an experiment that aims to empirically
evaluate the use of utility for decision making by comparing it against simpler
decision making mechanisms.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-02&engl=0}
}
@inproceedings {INPROC-2016-01,
author = {Santiago G{\'o}mez S{\'a}ez and Vasilios Andrikopoulos and Frank Leymann},
title = {{Consolidation of Performance and Workload Models in Evolving Cloud Application Topologies}},
booktitle = {Proceedings of the 6th International Conference on Cloud Computing and Service Science (CLOSER 2016)},
address = {Rome, Italy},
publisher = {SciTePress},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {160--169},
type = {Konferenz-Beitrag},
month = {April},
year = {2016},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
D.2.8 Software Engineering Metrics,
D.2.11 Software Engineering Software Architectures},
contact = {Santiago G{\'o}mez S{\'a}ez: santiago.gomez-saez@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The increase of available Cloud services and providers has contributed to
accelerate the development and has broaden the possibilities for building and
provisioning Cloud applications in heterogeneous Cloud environments. The
necessity for satisfying business and operational requirements in an agile and
rapid manner has created the need for adapting traditional methods and tooling
support for building and provisioning Cloud applications. Focusing on the
application's performance and its evolution, we observe a lack of support for
specifying, capturing, analyzing, and reasoning on the impact of using
different Cloud services and configurations. This paper bridges such a gap by
proposing the conceptual and tooling support to enhance Cloud application
topology models to capture and analyze the evolution of the application's
performance. The tooling support is built upon an existing modeling
environment, which is subsequently evaluated using the MediaWiki (Wikipedia)
application and its realistic workload.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-01&engl=0}
}
@inproceedings {INPROC-2015-43,
author = {Karolina Vukojevic-Haupt and Santiago G{\'o}mez S{\'a}ez and Florian Haupt and Dimka Karastoyanova and Frank Leymann},
title = {{A Middleware-centric Optimization Approach for the Automated Provisioning of Services in the Cloud}},
booktitle = {Proceedings of the 7th IEEE International Conference on Cloud Computing Technology and Science},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {174--179},
type = {Konferenz-Beitrag},
month = {Dezember},
year = {2015},
doi = {10.1109/CloudCom.2015.86},
keywords = {on-demand provisioning; cloud; service-oriented computing; eScience; optimization; dynamic provisioning; SOC},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
D.2.11 Software Engineering Software Architectures,
I.6.7 Simulation Support Systems},
contact = {karolina.vukojevic@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The on-demand provisioning of services, a cloud-based extension for traditional
service-oriented architectures, improves the handling of services in usage
scenarios where they are only used rarely and irregularly. However, the
standard process of service provisioning and de-provisioning shows still some
shortcomings when applying it in real world. In this paper, we introduce a
middleware-centric optimization approach that can be integrated in the existing
on-demand provisioning middleware in a loosely coupled manner, changing the
standard provisioning and de-provisioning behavior in order to improve it with
respect to cost and time. We define and implement a set of optimization
strategies, evaluate them based on a real world use case from the eScience
domain and provide qualitative as well as quantitative decision support for
effectively selecting and parametrizing a suitable strategy. Altogether, our
work improves the applicability of the existing on-demand provisioning approach
and system in real world, including guidance for selecting the suitable
optimization strategy for specific use cases.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-43&engl=0}
}
@inproceedings {INPROC-2015-35,
author = {Santiago G{\'o}mez S{\'a}ez and Vasilios Andrikopoulos and Michael Hahn and Dimka Karastoyanova and Andreas Wei{\ss}},
title = {{Enabling Reusable and Adaptive Modeling, Provisioning \& Execution of BPEL Processes}},
booktitle = {Proceedings of the 8th International Conference on Service-Oriented Computing and Applications (SOCA'15)},
address = {Rome, Italy},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2015},
language = {Englisch},
cr-category = {H.4.1 Office Automation,
C.2.4 Distributed Systems,
D.2.11 Software Engineering Software Architectures},
contact = {Santiago G{\'o}mez S{\'a}ez: gomez-saez@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The Business Process Execution Language (BPEL) is a well established language
for the definition of process models as service orchestrations. Service
orchestrations are used in conjunction with service choreographies in order to
create distributed, complex service-based applications. An important
requirement for such applications is the need for flexibility during both their
modeling and their execution. This work builds on this need by proposing an
extension of BPEL in order to allow the definition of abstract constructs on
the level of executable process models. Such constructs can be refined to
concrete activities at any time, enabling the reuse of existing models and the
dynamic adaptation to changing requirements. The design and implementation of
the language extension, as well as that of the supporting environment required
for the modeling, provisioning, and execution of such process models is further
discussed. A case study on a city-wide public transportation system offers the
means for an evaluation of the proposed approach.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-35&engl=0}
}
@inproceedings {INPROC-2015-19,
author = {Santiago G{\'o}mez S{\'a}ez and Vasilios Andrikopoulos and Roberto Jim{\'e}nez S{\'a}nchez and Frank Leymann and Johannes Wettinger},
title = {{Dynamic Tailoring and Cloud-based Deployment of Containerized Service Middleware}},
booktitle = {Proceedings of the 8th International Conference on Cloud Computing (CLOUD 2015)},
address = {New York, 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 = {2015},
language = {Englisch},
cr-category = {D.2.11 Software Engineering Software Architectures,
C.2.4 Distributed Systems},
contact = {Santiago G{\'o}mez S{\'a}ez: santiago.gomez-saez@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The emergence and consolidation of container-based virtualization techniques
has simplified and accelerated the development, provisioning, and deployment of
applications for the Cloud. When considering the case of composite
service-based applications that rely on service middleware solutions for their
operation, container-based virtualization offers the opportunity for rapid and
efficient building and deployment of lightweight, optimally configured
middleware instances. As such, it provides an ideal tool for the purposes of
cloudifying existing middleware solutions and offering them as part of larger
PaaS offerings. As part of this effort, our investigation focuses on leveraging
and evaluating a container-based virtualization environment towards enabling
the assembly, provisioning, and execution of dynamically tailored instances to
satisfy service middleware communication requirements of specific applications.
For these purposes we scope the discussion on one particular type of messaging
middleware for composite service applications, the Enterprise Service Bus (ESB)
technology.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-19&engl=0}
}
@inproceedings {INPROC-2015-14,
author = {Santiago G{\'o}mez S{\'a}ez and Vasilios Andrikopoulos and Michael Hahn and Dimka Karastoyanova and Frank Leymann and Marigianna Skouradaki and Karolina Vukojevic-Haupt},
title = {{Performance and Cost Evaluation for the Migration of a Scientific Workflow Infrastructure to the Cloud}},
booktitle = {Proceedings of the 5th International Conference on Cloud Computing and Service Science (CLOSER 2015)},
publisher = {SciTePress},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {352--361},
type = {Konferenz-Beitrag},
month = {Mai},
year = {2015},
keywords = {Workflow Simulation; eScience; IaaS; Performance Evaluation; Cost Evaluation; Cloud Migration},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
D.2.8 Software Engineering Metrics,
D.2.11 Software Engineering Software Architectures},
contact = {Santiago G{\'o}mez S{\'a}ez: santiago.gomez-saez@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The success of the Cloud computing paradigm, together with the increase of
Cloud providers and optimized Infrastructure-as-a-Service (IaaS) offerings have
contributed to a raise in the number of research and industry communities that
are strong supporters of migrating and running their applications in the Cloud.
Focusing on eScience simulation-based applications, scientific workflows have
been widely adopted in the last years, and the scientific workflow management
systems have become strong candidates for being migrated to the Cloud. In this
research work we aim at empirically evaluating multiple Cloud providers and
their corresponding optimized and non-optimized IaaS offerings with respect to
their offered performance, and its impact on the incurred monetary costs when
migrating and executing a workflow-based simulation environment. The
experiments show significant performance improvements and reduced monetary
costs when executing the simulation environment in off-premise Clouds.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-14&engl=0}
}
@inproceedings {INPROC-2014-71,
author = {Michael Hahn and Santiago G{\'o}mez S{\'a}ez and Vasilios Andrikopoulos and Dimka Karastoyanova and Frank Leymann},
title = {{Development and Evaluation of a Multi-tenant Service Middleware PaaS Solution}},
booktitle = {Proceedings of the 7th International Conference on Utility and Cloud Computing (UCC 2014)},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {278--287},
type = {Konferenz-Beitrag},
month = {Dezember},
year = {2014},
doi = {10.1109/UCC.2014.37},
keywords = {Multi-tenancy; Cloud middleware; PaaS; Performance Evaluation},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
H.4.1 Office Automation},
contact = {Michael Hahn: michael.hahn@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {In many modern systems, applications or services are realized as compositions
of multiple existing services that can be enacted by Service Composition
Engines (SCEs), which provide the required functionality to enable their
definition and execution. SCEs typically use the capabilities of an Enterprise
Service Bus (ESB) which serves as the messaging hub between the composed
services aiming at ensuring their integration. Together, an SCE and ESB
solution comprise the service middleware required for the definition and
execution of service-based composite applications. Offering a service
middleware solution as a service creates a PaaS offering that allows the
service consumers to share the service middleware solution in a multi-tenant
manner. However, multi-tenancy support for service middleware solutions remains
an open issue. For this purpose, in this work we introduce a general
architecture for the realization of a multi-tenant service middleware PaaS
solution. This architecture is prototypically realized based on open-source,
multi-tenant ESB and SCE solutions. The resulting service middleware provides
configurability for service compositions, tenant-aware messaging, and
tenant-based administration and management of the SCE and the ESB. We also
present an empirical evaluation of the multi-tenant service middleware with
focus on the SCE. The results of these experiments show a performance
degradation within acceptable limits when scaling the number of tenants and
tenant users.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-71&engl=0}
}
@inproceedings {INPROC-2014-70,
author = {Santiago G{\'o}mez S{\'a}ez},
title = {{Design Support for Performance-aware Cloud Application (Re-)Distribution}},
booktitle = {Proceedings of the PhD Symposium at the 3rd European Conference on Service-Oriented and Cloud Computing (ESOCC 2014)},
publisher = {Jenaer Schriften zur Mathematik und Informatik},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {6--11},
type = {Konferenz-Beitrag},
month = {September},
year = {2014},
language = {Englisch},
cr-category = {D.2.11 Software Engineering Software Architectures,
C.2.4 Distributed Systems},
contact = {Santiago G{\'o}mez S{\'a}ez: gomez-saez@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The Cloud computing paradigm emerged by establishing innovative resources
provisioning and consumption models. Together with the improvement of resource
management techniques, these models have contributed to an increase in the
number of application developers that are strong supporters of partially or
completely migrating their application to a highly scalable and pay-per-use
infrastructure. However, due to the continuous growth of Cloud providers and
Cloud offerings, Cloud application developers nowadays must face additional
application design challenges related to the efficient selection of such
offerings to optimally distribute the application in a Cloud infrastructure.
Focusing on the performance aspects of the application, additional challenges
arise, as application workloads fluctuate over time, and therefore produce a
variation of the infrastructure resources demands. In this research work we aim
to define and realize the underpinning concepts towards supporting the optimal
(re-)distribution of an application in the Cloud in order to handle fluctuating
over time workloads.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-70&engl=0}
}
@inproceedings {INPROC-2014-69,
author = {Michael Hahn and Santiago G{\'o}mez S{\'a}ez and Vasilios Andrikopoulos and Dimka Karastoyanova and Frank Leymann},
title = {{SCE^MT: A Multi-tenant Service Composition Engine}},
booktitle = {Proceedings of the 7th International Conference on Service-Oriented Computing and Applications (SOCA'14)},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {89--96},
type = {Konferenz-Beitrag},
month = {November},
year = {2014},
doi = {10.1109/SOCA.2014.9},
keywords = {Multi-tenancy; Service Composition Engine; Cloud middleware; Performance Evaluation},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
contact = {Michael Hahn: michael.hahn@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The support of multi-tenancy is an essential requirement for leveraging the
full capacity of Cloud computing. Multi-tenancy enables service providers to
maximize the utilization of their infrastructure and to reduce the servicing
costs per customer, thus indirectly benefiting also the customers. In addition,
it allows both providers and consumers to reap the advantages of Cloud-based
applications configurable for the needs of different tenants. Nowadays, new
applications or services are typically compositions of multiple existing
services. Service Composition Engines (SCEs) provide the required functionality
to enable the definition and execution of such compositions. Multi-tenancy on
the level of SCEs allows for both process model, as well as underlying
infrastructure sharing. Towards the goal of enabling multi-tenancy of SCEs, in
this paper, we investigate the requirements and define a general architecture
for the realization of a multi-tenant SCE solution. This architecture is
prototypically realized based on an open-source SCE implementation and
integrated into an existing multi-tenant aware Enterprise Service Bus (ESB).
The performance evaluation of our prototype shows promising results in terms of
the degradation introduced due to processing and communication overhead.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-69&engl=0}
}
@inproceedings {INPROC-2014-60,
author = {Andreas Wei{\ss} and Santiago G{\'o}mez S{\'a}ez and Michael Hahn and Dimka Karastoyanova},
title = {{Approach and Refinement Strategies for Flexible Choreography Enactment}},
booktitle = {22nd International Conference on Cooperative Information Systems (CoopIS 2014)},
editor = {H. Panetto et al. R. Meersman},
publisher = {Springer Berlin Heidelberg},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {93--111},
type = {Konferenz-Beitrag},
month = {Oktober},
year = {2014},
doi = {10.1007/978-3-662-45563-0_6},
keywords = {Process Flexibility, Choreography Flexibility, Refinement Strategies, Late Modeling, Late Selection, Process Fragments},
language = {Englisch},
cr-category = {H.4.1 Office Automation},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Collaborative, Dynamic \& Complex (CDC) systems such as adaptive pervasive
systems, eScience applications, and complex business systems inherently require
modeling and run time exibility. Since domain problems in CDC systems are
expressed as service choreographies and enacted by service orchestrations, we
propose an approach introducing placeholder modeling constructs usable both on
the level of choreographies and orchestrations, and a classi cation of
strategies for their re nement to executable work ows. These abstract modeling
constructs allow deferring the modeling decisions to later points in the life
cycle of choreographies. This supports run time scenarios such as incorporating
new participants into a choreography after its enactment has started or
enhancing the process logic of some of the participants. We provide a
prototypical implementation of the approach and evaluate it by means of a case
study.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-60&engl=0}
}
@inproceedings {INPROC-2014-57,
author = {David Richard Sch{\"a}fer and Santiago G{\'o}mez S{\'a}ez and Thomas Bach and Vasilios Andrikopoulos and Muhammad Adnan Tariq},
title = {{Towards Ensuring High Availability in Collective Adaptive Systems}},
booktitle = {Proceedings of the First International Workshop of Business Processes in Collective Adaptive Systems: BPCAS'14; Eindhoven, Netherlands, September 8, 2014},
publisher = {Springer},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
type = {Workshop-Beitrag},
month = {September},
year = {2014},
keywords = {workflows; high availability; service discovery; process fragment injection},
language = {Englisch},
cr-category = {D.2.0 Software Engineering General,
D.2.11 Software Engineering Software Architectures,
D.2.12 Software Engineering Interoperability,
C.2.4 Distributed Systems,
C.4 Performance of Systems},
ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-57/INPROC-2014-57.pdf},
contact = {david.schaefer@ipvs.uni-stuttgart.de},
department = {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 = {Collective Adaptive Systems support the interaction and adaptation of virtual
and physical entities towards achieving common objectives. For these systems,
several challenges at the modeling, provisioning, and execution phases arise.
In this position paper, we define the necessary underpinning concepts and
identify requirements towards ensuring high availability in such systems. More
specifically, based on a scenario from the EU Project ALLOW Ensembles, we
identify the necessary requirements and derive an architectural approach that
aims at ensuring high availability by combining active workflow replication,
service selection, and dynamic compensation techniques.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-57&engl=0}
}
@inproceedings {INPROC-2014-48,
author = {Vasilios Andrikopoulos and Anja Reuter and Santiago G{\'o}mez S{\'a}ez and Frank Leymann},
title = {{A GENTL Approach for Cloud Application Topologies}},
booktitle = {Proceedings of the Third European Conference on Service-Oriented and Cloud Computing (ESOCC 2014)},
publisher = {Springer},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
series = {Lecture Notes in Computer Science (LNCS)},
pages = {1--11},
type = {Konferenz-Beitrag},
month = {September},
year = {2014},
keywords = {application topology language; annotation schemes; application distribution; cloud migration},
language = {Englisch},
cr-category = {D.2.2 Software Engineering Design Tools and Techniques,
D.2.7 Software Engineering Distribution, Maintenance, and Enhancement,
H.4.2 Information Systems Applications Types of Systems},
contact = {vasilios.andrikopoulos@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The availability of an increasing number of cloud offerings allows for
innovative solutions in designing applications for the cloud and in adapting
existing ones for this environment. An important ingredient in identifying the
optimal distribution of an application in the cloud, potentially across
offerings and providers, is a robust topology model that can be used for the
automated deployment and management of the application. In order to support
this process, in this work we present an application topology language aimed
for cloud applications that is generic enough to allow the mapping from other
existing languages and comes with a powerful annotation mechanism already
built-in. We discuss its supporting environment that we developed and show how
it can be used in practice to assist application designers.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-48&engl=0}
}
@inproceedings {INPROC-2014-45,
author = {Santiago G{\'o}mez S{\'a}ez and Vasilios Andrikopoulos and Frank Leymann},
title = {{Performance-aware Application Distribution in the Cloud}},
booktitle = {Proceedings of the Workshop on Enterprise Architekturen mit Big Data \& Cloud (EABDC 2014)},
publisher = {Gesellschaft f{\"u}r Informatik e.V. (GI)},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--9},
type = {Workshop-Beitrag},
month = {September},
year = {2014},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
D.2.8 Software Engineering Metrics},
contact = {Santiago G{\'o}mez S{\'a}ez: santiago.gomez-saez@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The emergence of Cloud computing and the improvement of resource management
techniques have contributed to an increase in the number of application
developers that are strong supporters of partially or completely migrating
their application to a highly scalable and pay-per-use infrastructure. In this
work in progress paper we begin the analysis on how to optimally distribute the
application layers in the Cloud in order to adapt its topology to handle
oscillating over time workloads. More specifically, through an empirical
workload analysis and characterization we present our initial evaluation of an
application persistence layer's performance under different deployment
scenarios.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-45&engl=0}
}
@inproceedings {INPROC-2014-44,
author = {Santiago G{\'o}mez S{\'a}ez and Vasilios Andrikopoulos and Florian Wessling and Clarissa Cassales Marquezan},
title = {{Cloud Adaptation \& Application (Re-)Distribution: Bridging the two Perspectives}},
booktitle = {Proceedings of the First International Workshop on Engineering Cloud Applications \& Services (EnCASE 2014)},
publisher = {IEEE Computer Society Press},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {163--172},
type = {Workshop-Beitrag},
month = {September},
year = {2014},
language = {Englisch},
cr-category = {D.2.11 Software Engineering Software Architectures,
C.2.4 Distributed Systems},
contact = {Santiago G{\'o}mez S{\'a}ez: santiago.gomez-saez@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Cloud developers have to make several decisions when running their application
in a cloud environment that may lead to conflicting objectives, inefficient
deployment, and inappropriate or not existing adaptation strategies. Proper
decision-support tools and processes are therefore needed to make cloud
developers aware of the issues that need to be considered when deploying and
running applications in the Cloud. Current decision support tools for cloud
developers do not provide a structured and organized process in which the cloud
developers can systematically check their choices when planning the deployment,
execution, and adaptation of applications in the Cloud. In this paper, we
combine two previous works and introduce an approach for identifying the
options for (re-)deploying application in cloud providers infrastructures and
the possible strategies of adaptation that can be used by the deployed
application at runtime. The key contribution is a support process that
synthesizes the two approaches. We also describe a case study where our support
process is applied and we indicate the alternatives for application
(re-)deployment and adaptation.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-44&engl=0}
}
@inproceedings {INPROC-2014-27,
author = {Santiago G{\'o}mez S{\'a}ez and Vasilios Andrikopoulos and Frank Leymann and Steve Strauch},
title = {{Towards Dynamic Application Distribution Support for Performance Optimization in the Cloud}},
booktitle = {Proceedings of the 7th IEEE International Conference on Cloud Computing (IEEE CLOUD 2014); 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 = {248--255},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2014},
keywords = {Synthetic Workload; Benchmark; Application Distribution; Application Deployment; Relational Database; TPC; Database-as-a-Service (DBaaS)},
language = {Englisch},
cr-category = {D.2.11 Software Engineering Software Architectures,
C.2.4 Distributed Systems,
D.2.8 Software Engineering Metrics},
contact = {Santiago G{\'o}mez S{\'a}ez: gomez-saez@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The Cloud computing paradigm emerged by establishing new resources provisioning
and consumption models. Together with the improvement of resource management
techniques, these models have contributed to an increase in the number of
application developers that are strong supporters of partially or completely
migrating their application to a highly scalable and pay-per-use
infrastructure. In this paper we derive a set of functional and non-functional
requirements and propose a process-based approach to support the optimal
distribution of an application in the Cloud in order to handle fluctuating over
time workloads. Using the TPC-H workload as the basis, and by means of
empirical workload analysis and characterization, we evaluate the application
persistence layer's performance under different deployment scenarios using
generated workloads with particular behavior characteristics.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-27&engl=0}
}
@inproceedings {INPROC-2014-20,
author = {Vasilios Andrikopoulos and Marina Bitsaki and Antonio Bucchiarone and Santiago G{\'o}mez S{\'a}ez and Dimka Karastoyanova and Frank Leymann and Christos Nikolaou and Marco Pistore},
title = {{A Game Theoretic Approach for Managing Multi-Modal Urban Mobility Systems}},
booktitle = {Proceedings of the 5th International Conference on Applied Human Factors and Ergonomics (AHFE 2014)},
address = {Krak{\'o}w, Poland},
publisher = {CRC Press/Taylor \& Francis},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
type = {Konferenz-Beitrag},
month = {Juli},
year = {2014},
language = {Englisch},
cr-category = {D.2.0 Software Engineering General,
G.4 Mathematical Software,
I.1.2 Symbolic and Algebraic Manipulation Algorithms,
I.2.11 Distributed Artificial Intelligence},
contact = {Vasilios Andrikopoulos: andrikopoulos@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Collective adaptive systems provide secure and robust collaboration between
heterogeneous entities such as humans and computer systems. Such entities have
potentially conflicting goals that attempt to satisfy by interacting with each
other. Understanding and analyzing their behavior and evolution requires
technical, social and economic aspects of modeling. In this paper, we develop a
new design principle to describe an integrated and multimodal urban mobility
system and model the interactions of various entities by means of game
theoretic techniques.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-20&engl=0}
}
@inproceedings {INPROC-2014-19,
author = {Vasilios Andrikopoulos and Santiago G{\'o}mez S{\'a}ez and Frank Leymann and Johannes Wettinger},
title = {{Optimal Distribution of Applications in the Cloud}},
booktitle = {Proceedings of the 26th Conference on Advanced Information Systems Engineering (CAiSE 2014)},
editor = {Matthias Jarke and John Mylopoulos and Christoph Quix},
publisher = {Springer},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
series = {Lecture Notes in Computer Science (LNCS)},
pages = {1--15},
type = {Konferenz-Beitrag},
month = {Juni},
year = {2014},
keywords = {application topology; distribution optimization; cloud computing; operational expenses},
language = {Englisch},
cr-category = {D.2.11 Software Engineering Software Architectures,
C.2.4 Distributed Systems},
contact = {vasilios.andrikopoulos@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {In an environment of constant change and variation driven by competition and
innovation, a software service can rarely remain stable. Being able to manage
and control the evolution of services is therefore an important goal for the
Service-Oriented paradigm. This work extends existing and widely-adopted
theories from software engineering, programming languages, service oriented
computing and other related fields to provide the fundamental ingredients
required to guarantee that spurious results and inconsistencies that may occur
due to uncontrolled service changes are avoided. The presented work provides a
unifying theoretical framework for controlling the evolution of services that
deals with structural, behavioral and QoS level-induced service changes in a
type-safe manner. The goal of the work is to ensure correct version transitions
so that previous and future clients can use a service in a consistent manner.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-19&engl=0}
}
@inproceedings {INPROC-2014-11,
author = {Vasilios Andrikopoulos and Marina Bitsaki and Santiago G{\'o}mez S{\'a}ez and Dimka Karastoyanova and Christos Nikolaou and Alina Psycharaki},
title = {{Utility-based Decision Making in Collective Adaptive Systems}},
booktitle = {Proceedings of the Fourth International Conference on Cloud Computing and Service Science (CLOSER'14)},
publisher = {SciTePress},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {308--314},
type = {Konferenz-Beitrag},
month = {April},
year = {2014},
language = {Englisch},
cr-category = {D.2.0 Software Engineering General,
D.2.11 Software Engineering Software Architectures,
D.2.12 Software Engineering Interoperability},
contact = {Vasilios Andrikopoulos: vasilios.andrikopoulos@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Large-scale systems comprising of multiple heterogeneous entities are directly
influenced by the interactions of their participating entities. Such entities,
both physical and virtual, attempt to satisfy their objectives by dynamically
collaborating with each other, and thus forming collective adaptive systems.
These systems are subject to the dynamicity of the entities' objectives, and to
changes to the environment. In this work we focus on the latter, i.e. on
providing the means for entities in such systems to model, monitor and evaluate
their perceived utility by participating in the system. This allows for them to
make informed decisions about their interactions with other entities in the
system. For this purpose we propose a utility-based approach for decision
making, as well as an architecture that allows for the support of this
approach.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-11&engl=0}
}
@inproceedings {INPROC-2014-08,
author = {Vasilios Andrikopoulos and Santiago G{\'o}mez S{\'a}ez and Dimka Karastoyanova and Andreas Wei{\ss}},
title = {{Collaborative, Dynamic \& Complex Systems: Modeling, Provision \& Execution}},
booktitle = {Proceedings of the Fourth International Conference on Cloud Computing and Service Science (CLOSER'14)},
publisher = {SciTePress},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {276--286},
type = {Konferenz-Beitrag},
month = {April},
year = {2014},
language = {Englisch},
cr-category = {D.2.0 Software Engineering General,
D.2.11 Software Engineering Software Architectures,
D.2.12 Software Engineering Interoperability},
contact = {Vasilios Andrikopoulos: andrikopoulos@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Service orientation has significantly facilitated the development of complex
distributed systems spanning multiple organizations. However, different
application areas approach such systems in domain-specific ways, focusing only
on particular aspects relevant for their application types. As a result, we
observe a very fragmented landscape of service-oriented systems, which does not
enable collaboration across organizations. To address this concern, in this
work we introduce the notion of Collaborative, Dynamic and Complex (CDC)
systems and position them with respect to existing technologies. In addition,
we present how CDC systems are modeled and the steps to provision and execute
them. Furthermore, we contribute an architecture and prototypical
implementation, which we evaluate by means of a case study in a Cloud-enabled
context-aware pervasive application.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-08&engl=0}
}
@inproceedings {INPROC-2014-06,
author = {Steve Strauch and Vasilios Andrikopoulos and Santiago G{\'o}mez S{\'a}ez and Frank Leymann},
title = {{Transparent Access to Relational Databases in the Cloud Using a Multi-Tenant ESB}},
booktitle = {Proceedings of the 4th International Conference on Cloud Computing and Service Science (CLOSER'14)},
publisher = {SciTePress},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {5--14},
type = {Konferenz-Beitrag},
month = {April},
year = {2014},
keywords = {Data Access Layer; Relational Databases; Enterprise Service Bus (ESB); Multi-Tenancy},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
C.4 Performance of Systems,
D.2.11 Software Engineering Software Architectures,
H.2.0 Database Management General,
H.2.4 Database Management Systems},
contact = {a href=``http://www.iaas.uni-stuttgart.de/institut/mitarbeiter/strauch''Steve Strauch/ a},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {In the last years Cloud computing has become popular among IT organizations
aiming to reduce their operational costs. Applications can be designed to run
in the Cloud, or can be partially or completely migrated to it. Migrating the
data layer of an application to the Cloud, however, implies that existing
applications might need to be adapted in order to access their migrated to the
Cloud databases. In this work we examine how we can use an existing ESB to
enable transparent access to the relational data store running either in the
Cloud or on-premise. The goal of our approach is to minimize the effort
required to adapt the application. In particular, we discuss the requirements
and prototype realization of a Cloud aware data access layer for transparent
data access, using an existing open source and multi-tenant aware ESB as the
basis. We then evaluate the performance of our proposed solution by considering
different Cloud providers and using example data from an existing benchmark as
application workload.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-06&engl=0}
}
@inproceedings {INPROC-2014-02,
author = {Santiago G{\'o}mez S{\'a}ez and Vasilios Andrikopoulos and Frank Leymann and Steve Strauch},
title = {{Evaluating Caching Strategies for Cloud Data Access using an Enterprise Service Bus}},
booktitle = {Proceedings of the IEEE International Conference on Cloud Engineering (IEEE IC2E 2014)},
address = {Boston, Massachusetts, USA},
publisher = {IEEE Computer Society},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {289--294},
type = {Konferenz-Beitrag},
month = {M{\"a}rz},
year = {2014},
keywords = {Multi-tenancy; Enterprise Service Bus (ESB); Cache; Relational Databases},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
H.3.4 Information Storage and Retrieval Systems and Software},
contact = {E-Mail: santiago.gomez-saez@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Nowadays different Cloud services enable enterprises to migrate applications to
the Cloud. An application can be partially migrated by replacing some of its
components with Cloud services, or by migrating one or multiple of its layers
to the Cloud. As a result, accessing application data stored off-premise
requires mechanisms to mitigate the negative impact on Quality of Service
(QoS), e.g. due to network latency. In this work, we propose and realize an
approach for transparently accessing data migrated to the Cloud using a
multi-tenant open source Enterprise Service Bus (ESB) as the basis.
Furthermore, we enhance the ESB with QoS awareness by integrating it with an
open source caching solution. For evaluation purposes we generate a
representative application workload using data from the TPC-H benchmark. Based
on this workload, we then evaluate the optimal caching strategy among multiple
eviction algorithms when accessing relational databases located at different
Cloud providers.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-02&engl=0}
}
@inproceedings {INPROC-2013-55,
author = {Vasilios Andrikopoulos and Santiago G{\'o}mez S{\'a}ez and Dimka Karastoyanova and Andreas Wei{\ss}},
title = {{Towards Collaborative, Dynamic \& Complex Systems}},
booktitle = {Proceedings of the 6th International Conference on Service-Oriented Computing and Applications (SOCA'13)},
publisher = {IEEE},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
series = {IEEE Computer Society},
pages = {1--5},
type = {Konferenz-Beitrag},
month = {Dezember},
year = {2013},
keywords = {collaborative, dynamic \& complex systems; service orchestration \& choreography; pervasive computing; service networks; context-awareness},
language = {Englisch},
cr-category = {D.2.0 Software Engineering General,
D.2.11 Software Engineering Software Architectures,
D.2.12 Software Engineering Interoperability},
contact = {vasilios.andrikopoulos@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Service orientation has significantly facilitated the development of complex
distributed systems spanning multiple organizations. However, different
application areas approach such systems in domain-specific ways, focusing on
particular aspects relevant only for their application types. As a result, we
observe a very fragmented landscape of service-oriented systems, which does not
enable collaboration across organizations. To address this concern, in this
work we introduce the notion of Collaborative, Dynamic and Complex (CDC)
systems and position them with respect to existing technologies. In addition,
we present how CDC systems are modeled and the steps to provision and execute
them. We also contribute an architecture enabling CDC Systems with full life
cycle coverage that allows for leveraging service-oriented and Cloud-related
technologies.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-55&engl=0}
}
@inproceedings {INPROC-2013-54,
author = {Vasilios Andrikopoulos and Antonio Bucchiarone and Santiago G{\'o}mez S{\'a}ez and Dimka Karastoyanova and Claudio Antares Mezzina},
title = {{Towards Modeling and Execution of Collective Adaptive Systems}},
booktitle = {Proceedings of the 9th International Workshop on Engineering Service-Oriented Applications (WESOA'13)},
publisher = {Springer},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {1--12},
type = {Workshop-Beitrag},
month = {Dezember},
year = {2013},
language = {Englisch},
cr-category = {D.2.0 Software Engineering General,
D.2.11 Software Engineering Software Architectures,
D.2.12 Software Engineering Interoperability},
contact = {vasilios.andrikopoulos@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Collective Adaptive Systems comprise large numbers of heterogeneous entities
that can join and leave the system at any time depending on their own
objectives. In the scope of pervasive computing, both physical and virtual
entities may exist, e.g., buses and their passengers using mobile devices, as
well as city-wide traffic coordination systems. In this paper we introduce a
novel conceptual framework that enables Collective Adaptive Systems based on
well-founded and widely accepted paradigms and technologies like service
orientation, distributed systems, context-aware computing and adaptation of
composite systems. Toward achieving this goal, we also present an architecture
that underpins the envisioned framework, discuss the current state of our
implementation effort, and we outline the open issues and challenges in the
field.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-54&engl=0}
}
@inproceedings {INPROC-2013-41,
author = {Steve Strauch and Vasilios Andrikopoulos and Santiago G{\'o}mez S{\'a}ez and Frank Leymann},
title = {{Implementation and Evaluation of a Multi-tenant Open-Source ESB}},
booktitle = {Proceedings of the 2nd European Conference on Service-Oriented and Cloud Computing (ESOCC'13)},
editor = {Lau Kung-Kiu and Lamersdorf Winfried and Pimentel Ernesto},
publisher = {Springer Berlin Heidelberg},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
series = {Lecture Notes in Computer Science (LNCS)},
volume = {8135},
pages = {79--93},
type = {Konferenz-Beitrag},
month = {September},
year = {2013},
isbn = {978-3-642-40650-8},
keywords = {Multi-tenancy; Enterprise Service Bus (ESB); ESB benchmarking; JBI specification; Platform as a Service},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
contact = {a href=``http://www.iaas.uni-stuttgart.de/institut/mitarbeiter/strauch''Steve Strauch/ a},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Offering applications as a service in the Cloud builds on the notion of
application multi-tenancy. Multi-tenancy, the sharing of application instances
and their underlying resources between users from different organizational
domains, allows service providers to maximize resource utilization and reduce
servicing costs per user. Realizing application multi-tenancy however requires
suitable enabling mechanisms offered by their supporting middleware.
Furthermore, the middleware itself can be multi-tenant in a similar fashion. In
this work we focus on enabling multi-tenancy for one of the most important
components in service-oriented middleware, the Enterprise Service Bus (ESB). In
particular, we discuss the prototype realization of a multi-tenant aware ESB,
using an open source solution as the basis. We then evaluate the performance of
our proposed solution by an ESB-specific benchmark that we extended for
multi-tenancy purposes.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-41&engl=0}
}
@inproceedings {INPROC-2013-17,
author = {Steve Strauch and Vasilios Andrikopoulos and Uwe Breitenb{\"u}cher and Santiago G{\'o}mez S{\'a}ez and Oliver Kopp and Frank Leymann},
title = {{Using Patterns to Move the Application Data Layer to the Cloud}},
booktitle = {Proceedings of the 5th International Conference on Pervasive Patterns and Applications (PATTERNS'13)},
publisher = {Xpert Publishing Services},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {26--33},
type = {Konferenz-Beitrag},
month = {Mai},
year = {2013},
keywords = {Data layer; Cloud applications; Data migration; Cloud Data Patterns; Cloud data stores},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
D.2.11 Software Engineering Software Architectures,
H.3.4 Information Storage and Retrieval Systems and Software},
contact = {a href=``http://www.iaas.uni-stuttgart.de/institut/mitarbeiter/strauch''Steve Strauch/ a},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Cloud services allow for hosting applications partially or completely in the
Cloud by migrating their components and data. Especially with respect to data
migration, a series of functional and non-functional challenges like data
confidentiality arise when considering private and public Cloud data stores. In
this paper we identify some of these challenges and propose a set of reusable
solutions for them, organized together as a set of Cloud Data Patterns.
Furthermore, we show how these patterns may impact the application architecture
and demonstrate how they can be used in practice by means of a use case.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-17&engl=0}
}
@inproceedings {INPROC-2012-45,
author = {Steve Strauch and Vasilios Andrikopoulos and Santiago G{\'o}mez S{\'a}ez and Frank Leymann and Dominik Muhler},
title = {{Enabling Tenant-Aware Administration and Management for JBI Environments}},
booktitle = {Proceedings of the 5th International Conference on Service-Oriented Computing and Applications (SOCA'12)},
publisher = {IEEE Computer Society Conference Publishing Services},
institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
pages = {206--213},
type = {Konferenz-Beitrag},
month = {Dezember},
year = {2012},
isbn = {978-1-4673-4775-4},
keywords = {Multi-tenancy; Enterprise Service Bus (ESB); JBI specification; Platform as a Service},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
C.4 Performance of Systems,
D.2.11 Software Engineering Software Architectures},
contact = {a href=``http://www.iaas.uni-stuttgart.de/institut/mitarbeiter/strauch''Steve Strauch/ a},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Enterprise Service Buses (ESBs) constitute a core middleware technology for
each modern Service-Oriented Architecture (SOA) solution. Given the popularity
of the Cloud paradigm, which is based on fundamental SOA concepts, it is only
therefore natural to look into how ESBs can be transformed into native building
blocks for Cloud platforms. As a first step of this effort, in this work we
investigate how ESBs can become multi-tenant aware, i.e. able to support
multiple tenants and their users sharing the same ESB instance. A generalized
architecture based on the JBI specification implemented by a number of open
source ESBs is presented for this purpose. We demonstrate the feasibility of
our proposal by means of a proof of concept realization and we evaluate the
performance of our solution against a non multi-tenant ESB that was used as the
baseline for our implementation.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-45&engl=0}
}
@article {ART-2014-12,
author = {Santiago G{\'o}mez S{\'a}ez and Vasilios Andrikopoulos and Frank Leymann and Steve Strauch},
title = {{Design Support for Performance Aware Dynamic Application (Re-)Distribution in the Cloud}},
journal = {IEEE Transactions on Services Computing},
publisher = {IEEE Computer Society},
volume = {8},
number = {2},
pages = {225--239},
type = {Artikel in Zeitschrift},
month = {Dezember},
year = {2014},
doi = {10.1109/TSC.2014.2381237},
language = {Englisch},
cr-category = {D.2.11 Software Engineering Software Architectures,
C.2.4 Distributed Systems,
D.2.8 Software Engineering Metrics},
contact = {Santiago G{\'o}mez S{\'a}ez: gomez-saez@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The wide adoption of the Cloud computing paradigm by many different domains has
increased both the number and type of available offerings as a service, e.g.
Database-as-a-service (DBaaS) or Platform-as-a-Service (PaaS), and with them
the possibilities in deploying and operating an application partially or
completely in the Cloud. The need for providing design support to application
developers in this environment is the focus of this work. Toward this goal, in
the following we first scope the discussion on the persistence layer of
applications and we investigate the effect of different deployment scenarios on
the performance of the application over time. Based on the results of this
analyses we then propose an application (re-)distribution design support
process, which we evaluate empirically by means of a well-known application.
The results of this evaluation both highlight the strengths of our proposal,
and at the same time, provide a clear path for the following steps in our work.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2014-12&engl=0}
}
@article {ART-2013-10,
author = {Steve Strauch and Vasilios Andrikopoulos and Santiago G{\'o}mez S{\'a}ez and Frank Leymann},
title = {{ESB^MT: A Multi-tenant Aware Enterprise Service Bus}},
journal = {International Journal of Next-Generation Computing},
publisher = {Perpetual Innovation Media Pvt. Ltd.},
volume = {4},
number = {3},
pages = {230--249},
type = {Artikel in Zeitschrift},
month = {November},
year = {2013},
issn = {0976-5034},
keywords = {Enterprise Service Bus; Multi-tenancy; Cloud-enabled middleware},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems},
contact = {a href=``http://www.iaas.uni-stuttgart.de/institut/mitarbeiter/strauch''Steve Strauch/ a},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {Multi-tenancy, the sharing of the whole technological stack by different
consumers at the same time, allows service providers to maximize resource
utilization and reduce servicing costs per customer. Essential components of
the contemporary enterprise environment like the Enterprise Service Bus (ESB)
are therefore required to raise to the challenge of supporting and enabling
multi-tenancy, becoming multi-tenant aware. Towards this goal, in this work we
discuss the requirements for multi-tenant ESB solutions as fundamental building
blocks in the Platform as a Service (PaaS) Cloud delivery model. Addressing
these requirements, we propose a solution for dealing with multiple tenant
contexts on the level of middleware, based on which we develop ESB^MT, an
implementation agnostic multi-tenant aware ESB architecture that we instantiate
based on the Apache ServiceMix ESB open source solution. Evaluating the
performance of our proposal required the extension of an ESB benchmark, the
results of which for different deployment options we also present in this work.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2013-10&engl=0}
}
@inbook {INBOOK-2016-02,
author = {Santiago G{\'o}mez S{\'a}ez and Vasilios Andrikopoulos and Michael Hahn and Dimka Karastoyanova and Frank Leymann and Marigianna Skouradaki and Karolina Vukojevic-Haupt},
title = {{Performance and Cost Trade-Off in IaaS Environments: A Scientific Workflow Simulation Environment Case Study}},
series = {Cloud Computing and Services Science},
publisher = {Springer},
series = {Communications in Computer and Information Science},
volume = {581},
pages = {153--170},
type = {Beitrag in Buch},
month = {Februar},
year = {2016},
language = {Englisch},
cr-category = {C.2.4 Distributed Systems,
D.2.8 Software Engineering Metrics,
D.2.11 Software Engineering Software Architectures},
contact = {Santiago G{\'o}mez S{\'a}ez: santiago.gomez-saez@iaas.uni-stuttgart.de},
department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
abstract = {The adoption of the workflow technology in the eScience domain has contributed
to the increase of simulation-based applications orchestrating different
services in a flexible and error-free manner. The nature of the provisioning
and execution of such simulations makes them potential candidates to be
migrated and executed in Cloud environments. The wide availability of
Infrastructure-as-a-Service (IaaS) Cloud offerings and service providers has
contributed to a raise in the number of supporters of partially or completely
migrating and running their scientific experiments in the Cloud. Focusing on
Scientific Workflow-based Simulation Environments (SWfSE) applications and
their corresponding underlying runtime support, in this research work we aim at
empirically analyzing and evaluating the impact of migrating such an
environment to multiple IaaS infrastructures. More specifically, we focus on
the investigation of multiple Cloud providers and their corresponding optimized
and non-optimized IaaS offerings with respect to their offered performance, and
its impact on the incurred monetary costs when migrating and executing a SWfSE.
The experiments show significant performance improvements and reduced monetary
costs when executing the simulation environment in off-premise Clouds.},
url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INBOOK-2016-02&engl=0}
}