@inproceedings {INPROC-2020-49,
   author = {Vladimir Yussupov and Uwe Breitenb{\"u}cher and Christoph Krieger and Frank Leymann and Jacopo Soldani and Michael Wurster},
   title = {{Pattern-based Modelling, Integration, and Deployment of Microservice Architectures}},
   booktitle = {Proceedings of the 2020 IEEE 24th International Enterprise Distributed Object Computing Conference (EDOC 2020)},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {40--50},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2020},
   doi = {10.1109/EDOC49727.2020.00015},
   keywords = {Microservice Architecture; Service Composition; Enterprise Integration Pattern; Model-driven Engineering},
   language = {Englisch},
   cr-category = {D.2.2 Software Engineering Design Tools and Techniques,     D.2.11 Software Engineering Software Architectures},
   ee = {https://is.ieis.tue.nl/edoc20/},
   contact = {Vladimir Yussupov yussupov@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Microservice-based architectures (MSAs) gained momentum in industrial and research communities since finer-grained and more independent components foster reuse and reduce time to market. However, to come from the design of MSAs to running applications, substantial knowledge and technology-specific expertise in the deployment and integration of microservices is needed. In this paper, we propose a model-driven and pattern-based approach for composing microservices, which facilitates the transition from architectural models to running deployments. Using a unified modelling for MSAs, including both their integration based on Enterprise Integration Patterns (EIPs) and deployment aspects, our approach enables automatically generating the artefacts for deploying microservice compositions. This helps abstracting away the underlying infrastructure including container orchestration platforms and middleware layer for service integration. To validate the feasibility of our approach, we illustrate its prototypical implementation, with Kubernetes used as container orchestration system and OpenFaaS used for managing integration logic, and we present a case study.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2020-49&engl=0}
}
@inproceedings {INPROC-2020-34,
   author = {Christoph Krieger and Uwe Breitenb{\"u}cher and Michael Falkenthal and Frank Leymann and Vladimir Yussupov and Uwe Zdun},
   title = {{Monitoring Behavioral Compliance with Architectural Patterns Based on Complex Event Processing}},
   booktitle = {Proceedings of the 8th European Conference on Service-Oriented and Cloud Computing (ESOCC 2020)},
   publisher = {Springer International Publishing},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {125--140},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2020},
   doi = {10.1007/978-3-030-44769-4_10},
   language = {Englisch},
   cr-category = {D.2.11 Software Engineering Software Architectures},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Architectural patterns assist in the process of architectural decision making as they capture architectural aspects of proven solutions. In many cases, the chosen patterns have system-wide implications on non-functional requirements such as availability, performance, and resilience. Ensuring compliance with the selected patterns is of vital importance to avoid architectural drift between the implementation and its desired architecture. Most of the patterns not only capture structural but also significant behavioral architectural aspects that need to be checked. In case all properties of the system are known before runtime, static compliance checks of application code and configuration files might be sufficient. However, in case aspects of the system dynamically evolve, e.g., due to manual reconfiguration, compliance with the architectural patterns also needs to be monitored during runtime. In this paper, we propose to link compliance rules to architectural patterns that specify behavioral aspects of the patterns based on runtime events using stream queries. These queries serve as input for a complex event processing component to automatically monitor architecture compliance of a running system. To validate the practical feasibility, we applied the approach to a set of architectural patterns in the domain of distributed systems and prototypically implemented a compliance monitor.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2020-34&engl=0}
}
@inproceedings {INPROC-2020-27,
   author = {Ghareeb Falazi and Uwe Breitenb{\"u}cher and Florian Daniel and Florian Lamparelli and Frank Leymann and Vladimir Yussupov},
   title = {{Smart Contract Invocation Protocol (SCIP): A Protocol for the Uniform Integration of Heterogeneous Blockchain Smart Contracts}},
   booktitle = {CAiSE 2020: Advanced Information Systems Engineering},
   editor = {Schahram Dustdar and Eric Yu and Camille Salinesi and Dominique Rieu and Vik Pant},
   address = {Cham},
   publisher = {Springer International Publishing},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {12127},
   pages = {134--149},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2020},
   doi = {10.1007/978-3-030-49435-3_9},
   keywords = {Smart Contract Invocation Protocol; SCIP; SCL; SCDL; Blockchain; Smart Contract; Integration},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     D.2.11 Software Engineering Software Architectures,     D.2.12 Software Engineering Interoperability},
   ee = {http://caise20.imag.fr/},
   contact = {Ghareeb Falazi ghareeb.falazi@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Blockchains are distributed ledgers that enable the disintermediation of collaborative processes and, at the same time, foster trust among partners. Modern blockchains support smart contracts, i.e., software deployed on the blockchain, and guarantee their repeatable, deterministic execution. Alas, blockchains and smart contracts lack standardization. Therefore, smart contracts come with heterogeneous properties, APIs and data formats. This hinders the integration of smart contracts running in different blockchains, e.g., into enterprise business processes. This paper introduces the Smart Contract Invocation Protocol (SCIP), which unifies interacting with smart contracts of different blockchains. The protocol supports invoking smart contract functions, monitoring function executions, emitted events, and transaction finality, as well as querying a blockchain. The protocol is accompanied by a prototypical implementation of a SCIP endpoint in the form of a gateway.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2020-27&engl=0}
}
@inproceedings {INPROC-2020-26,
   author = {Michael Wurster and Uwe Breitenb{\"u}cher and Lukas Harzenetter and Frank Leymann and Jacopo Soldani and Vladimir Yussupov},
   title = {{TOSCA Light: Bridging the Gap between the TOSCA Specification and Production-ready Deployment Technologies}},
   booktitle = {Proceedings of the 10th International Conference on Cloud Computing and Services Science (CLOSER)},
   publisher = {SciTePress},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {216--226},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2020},
   doi = {10.5220/0009794302160226},
   language = {Deutsch},
   cr-category = {C.0 Computer Systems Organization, General,     D.2 Software Engineering},
   contact = {Michael Wurster wurster@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {The automation of application deployment is critical because manually deploying applications is time-consuming, tedious, and error-prone. Several deployment automation technologies have been developed in recent years employing tool-specific deployment modeling languages. At the same time, the OASIS standard Topology Orchestration Specification for Cloud Applications (TOSCA) emerged as a means for describing cloud applications, i. e., their components and relationships, in a vendor-agnostic fashion. Despite TOSCA is widely used in research, it is not supported by the production-ready deployment automation technologies daily used by practitioners working with cloud-native applications, hence resulting in a gap between the state-of-the-art in research and state-of-practice in the industry. To help bridging this gap, we leverage the recently introduced Essential Deployment Metamodel (EDMM) and identify TOSCA Light, an EDMM-compliant subset of TOSCA, to enact the transformation from TOSCA to the vast majority of deployment automation technology-specific models used by today{\^a}€™s software industry. Further, we present an end-to-end TOSCA Light modeling and transformation workflow and show a prototypical implementation to validate our approach.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2020-26&engl=0}
}
@inproceedings {INPROC-2020-24,
   author = {Vladimir Yussupov and Uwe Breitenb{\"u}cher and Ayhan Kaplan and Frank Leymann},
   title = {{SEAPORT: Assessing the Portability of Serverless Applications}},
   booktitle = {Proceedings of the 10th International Conference on Cloud Computing and Services Science (CLOSER 2020)},
   editor = {Donald Ferguson and Markus Helfert and Claus Pahl},
   publisher = {SciTePress},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {456--467},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2020},
   doi = {10.5220/0009574104560467},
   language = {Englisch},
   cr-category = {D.2.0 Software Engineering General,     D.2.11 Software Engineering Software Architectures,     D.2.12 Software Engineering Interoperability},
   ee = {http://closer.scitevents.org},
   contact = {Vladimir Yussupov yussupov@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {The term serverless is often used to describe cloud applications that comprise components managed by third parties. Like any other cloud application, serverless applications are often tightly-coupled with providers, their features, models, and APIs. As a result, when their portability to another provider has to be assessed, application owners must deal with identification of heterogeneous lock-in issues and provider-specific technical details. Unfortunately, this process is tedious, error-prone, and requires significant technical expertise in the domains of serverless and cloud computing. In this work, we introduce SEAPORT, a method for automatically assessing the portability of serverless applications with respect to a chosen target provider or platform. The method introduces (i) a canonical serverless application model, and (ii) the concepts for portability assessment involving classification and components similarity calculation together with the static code analysis. The method aims to be compatible with existing migration concepts to allow using it as a complementary part for serverless use cases. We present an architecture of a decision support system supporting automated assessment of the given application model with respect to the target provider. To validate the technical feasibility of the method, we implement the system prototypically.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2020-24&engl=0}
}
@inproceedings {INPROC-2020-22,
   author = {Michael Zimmermann and Uwe Breitenb{\"u}cher and Lukas Harzenetter and Frank Leymann and Vladimir Yussupov},
   title = {{Self-Contained Service Deployment Packages}},
   booktitle = {Proceedings of the 10th International Conference on Cloud Computing and Services Science (CLOSER 2020)},
   editor = {Donald Ferguson and Markus Helfert and Claus Pahl},
   publisher = {SciTePress},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {371--381},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2020},
   isbn = {978-989-758-424-4},
   doi = {10.5220/0009414903710381},
   language = {Englisch},
   cr-category = {C.0 Computer Systems Organization, General,     D.2 Software Engineering},
   ee = {http://closer.scitevents.org/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Complex applications are typically composed of multiple components. In order to install these components all their dependencies need to be satisfied. Typically these dependencies are resolved, downloaded, and installed during the deployment time and in the target environment, e.g., using package manager of the operating system. However, under some circumstances this approach is not applicable, e.g., if the access to the Internet is limited or non-existing at all. For instance, Industry 4.0 environments often have no Internet access for security reasons. Thus, in these cases, deployment packages without external dependencies are required that already contain everything required to deploy the software. In this paper, we present an approach enabling the transformation of non-self-contained deployment packages into self-contained deployment packages. Furthermore, we present a method for developing self-contained deployment packages systematically. The practical feasibility is validated by a prototypical implementation following our proposed system architecture. Moreover, our prototype is evaluated by provisioning a LAMP stack using the open-source ecosystem OpenTOSCA.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2020-22&engl=0}
}
@inproceedings {INPROC-2019-41,
   author = {Michael Wurster and Uwe Breitenb{\"u}cher and Antonio Brogi and Ghareeb Falazi and Lukas Harzenetter and Frank Leymann and Jacopo Soldani and Vladimir Yussupov},
   title = {{The EDMM Modeling and Transformation System}},
   booktitle = {Service-Oriented Computing - ICSOC 2019 Workshops},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {294--298},
   type = {Demonstration},
   month = {Oktober},
   year = {2019},
   doi = {10.1007/978-3-030-45989-5_26},
   language = {Englisch},
   cr-category = {C.0 Computer Systems Organization, General,     D.2 Software Engineering},
   contact = {Michael Wurster wurster@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Since deployment automation technologies are heterogeneous regarding their supported features and modeling languages, selecting a concrete technology is difficult and can result in a lock-in. Therefore, we presented the Essential Deployment Metamodel (EDMM) in previous work that abstracts from concrete technologies and provides a normalized metamodel for creating technology-independent deployment models. In this demonstration, we present tool support for EDMM in the form of the EDMM Modeling and Transformation System, which enables (i) creating EDMM models graphically and (ii) automatically transforming them into models supported by concrete deployment automation technologies.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2019-41&engl=0}
}
@inproceedings {INPROC-2019-38,
   author = {Vladimir Yussupov and Uwe Breitenb{\"u}cher and Frank Leymann and Christian M{\"u}ller},
   title = {{Facing the Unplanned Migration of Serverless Applications: A Study on Portability Problems, Solutions, and Dead Ends}},
   booktitle = {Proceedings of the 12th IEEE/ACM International Conference on Utility and Cloud Computing (UCC 2019)},
   editor = {ACM},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {273--283},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2019},
   doi = {10.1145/3344341.3368813},
   keywords = {Serverless; Function-as-a-Service; FaaS; Portability; Migration},
   language = {Englisch},
   cr-category = {D.2.0 Software Engineering General,     D.2.11 Software Engineering Software Architectures,     D.2.12 Software Engineering Interoperability},
   ee = {https://www.ucc-conference.org},
   contact = {Vladimir Yussupov yussupov@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Serverless computing focuses on developing cloud applications that comprise components fully managed by providers. Function-as-a-Service (FaaS) service model is often associated with the term serverless as it allows developing entire applications by composing provider-managed, event-driven code snippets. However, such reduced control over the infrastructure and tight-coupling with provider's services amplify the various lock-in problems. In this work, we explore the challenges of migrating serverless, FaaS-based applications across cloud providers. To achieve this, we conduct an experiment in which we implement four prevalent yet intentionally simple serverless use cases and manually migrate them across three popular commercial cloud providers. The results show that even when migrating simple use cases, developers encounter multiple aspects of a lock-in problem. Moreover, we present a categorization of the problems and discuss the feasibility of possible solutions.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2019-38&engl=0}
}
@inproceedings {INPROC-2019-37,
   author = {Vladimir Yussupov and Uwe Breitenb{\"u}cher and Frank Leymann and Michael Wurster},
   title = {{A Systematic Mapping Study on Engineering Function-as-a-Service Platforms and Tools}},
   booktitle = {Proceedings of the 12th IEEE/ACM International Conference on Utility and Cloud Computing (UCC 2019)},
   editor = {ACM},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {229--240},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2019},
   doi = {10.1145/3344341.3368803},
   keywords = {Serverless; FaaS; Function-as-a-Service; Systematic Mapping Study},
   language = {Englisch},
   cr-category = {C.0 Computer Systems Organization, General,     C.2.4 Distributed Systems,     D.2 Software Engineering},
   ee = {https://www.ucc-conference.org},
   contact = {Vladimir Yussupov yussupov@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Function-as-a-Service (FaaS) is a novel cloud service model allowing to develop fine-grained, provider-managed cloud applications. In this work, we investigate which challenges motivate researchers to introduce or enhance FaaS platforms and tools. We use a systematic mapping study method to collect and analyze the relevant scientific literature, which helps us answering the three clearly-defined research questions. We design our study using well-established guidelines and systematically apply it to 62 selected publications. The collected and synthesized data provides useful insights into the main challenges that motivate researchers to work on this topic and can be helpful in identifying research gaps for future research.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2019-37&engl=0}
}
@inproceedings {INPROC-2019-36,
   author = {Vladimir Yussupov and Uwe Breitenb{\"u}cher and Michael Hahn and Frank Leymann},
   title = {{Serverless Parachutes: Preparing Chosen Functionalities for Exceptional Workloads}},
   booktitle = {Proceedings of the 2019 IEEE 23rd International Enterprise Distributed Object Computing Conference (EDOC 2019)},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {226--235},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2019},
   doi = {10.1109/EDOC.2019.00035},
   keywords = {Serverless; FaaS; Function-as-a-Service; Scalability; Failover; Annotation},
   language = {Englisch},
   cr-category = {D.2.2 Software Engineering Design Tools and Techniques,     D.2.11 Software Engineering Software Architectures,     D.3.4 Programming Languages Processors},
   ee = {https://edoc2019.sciencesconf.org/},
   contact = {Vladimir Yussupov yussupov@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Function-as-a-Service (FaaS) is an emerging cloud service model that enables composing applications using arbitrary, small, and event-driven code snippets managed by cloud providers and that can be scaled to zero. The scalability properties of FaaS look attractive for handling rare or unexpected high loads that affect only particular functionalities of the application. However, deciding on the component granularity upfront or reengineering the architecture of an entire application for rare workloads is often a very difficult challenge or even infeasible. In this work, we introduce a method that prepares annotated functionalities for handling rare workloads by automatically extracting them from the source code of the application and additionally deploying them as FaaS functions, while keeping the original application's functionalities and architecture unchanged. In this way, the benefits of FaaS can be leveraged without the need to reengineer the application only for rare cases. We validate our method by means of a prototype, evaluate its feasibility in a set of experiments, and discuss limitations and future work.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2019-36&engl=0}
}
@inproceedings {INPROC-2019-35,
   author = {Ghareeb Falazi and Michael Hahn and Uwe Breitenb{\"u}cher and Frank Leymann and Vladimir Yussupov},
   title = {{Process-Based Composition of Permissioned and Permissionless Blockchain Smart Contracts}},
   booktitle = {Proceedings of the 2019 IEEE 23rd International Enterprise Distributed Object Computing Conference (EDOC 2019)},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {77--87},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2019},
   doi = {10.1109/EDOC.2019.00019},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     D.2.2 Software Engineering Design Tools and Techniques,     D.2.11 Software Engineering Software Architectures},
   ee = {https://edoc2019.sciencesconf.org/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Blockchains are distributed systems that facilitate the interaction of autonomous entities with limited mutual trust. Many of them support transactional applications known as smart contracts, which access and modify the shared world state. Permissionless blockchains are completely decentralized and do not require mutual trust between interacting peers, but at the expense of having low performance and limited data confidentiality capabilities. On the other hand, permissioned blockchains solve these issues, but sacrifice complete decentralization and involve more trust assumptions. Therefore, there is no single blockchain system suitable for all use-cases. However, this becomes a serious integration challenge for enterprises that need to interact with multiple permissioned and permissionless blockchains in the same context. To facilitate this, we propose an approach that enables composing smart contract functions of various permissioned and permissionless blockchain systems by providing the ability to invoke them directly from business process models using a new task type. To keep this task blockchain-agnostic, we designed a generic technique to identify smart contract functions, as well as a generic metric to describe the degree-of-confidence in the finality of blockchain transactions. Thereby, the proposed approach extends our previous work, BlockME, which provides business modeling extensions only suitable for interacting with permissionless blockchains. To validate the practical feasibility of our approach, we provide a detailed system architecture and a prototypical implementation supporting multiple blockchains. Keywords: blockchains, business process management, permissioned blockchains, smart contract composition, blockchain access layer, BlockME2},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2019-35&engl=0}
}
@inproceedings {INPROC-2018-48,
   author = {Michael Wurster and Uwe Breitenb{\"u}cher and K{\'a}lm{\'a}n K{\'e}pes and Frank Leymann and Vladimir Yussupov},
   title = {{Modeling and Automated Deployment of Serverless Applications using TOSCA}},
   booktitle = {Proceedings of the IEEE 11th International Conference on Service-Oriented Computing and Applications (SOCA)},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {73--80},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2018},
   doi = {10.1109/SOCA.2018.00017},
   keywords = {Serverless; Multi-Cloud; Modeling; Automated Deployment; TOSCA},
   language = {Englisch},
   cr-category = {D.2.2 Software Engineering Design Tools and Techniques,     D.2.9 Software Engineering Management,     D.2.11 Software Engineering Software Architectures},
   contact = {Michael Wurster michael.wurster@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {The serverless computing paradigm brings multiple benefits to application developers who are interested in consuming computing resources as services without the need to manage physical capacities or limits. There are several deployment technologies and languages available suitable for deploying applications to a single cloud provider. However, for multi-cloud application deployments, multiple technologies have to be used and orchestrated. In addition, the event-driven nature of serverless computing imposes further requirements on modeling such application structures in order to automate their deployment. In this paper, we tackle these issues by introducing an event-driven deployment modeling approach using the standard Topology and Orchestration Specification for Cloud Applications (TOSCA) that fully employs the suggested standard lifecycle to provision and manage multi-cloud serverless applications. To show the feasibility of our approach, we extended the existing TOSCA-based ecosystem OpenTOSCA.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2018-48&engl=0}
}
@inproceedings {INPROC-2018-43,
   author = {Ghareeb Falazi and Uwe Breitenb{\"u}cher and Michael Falkenthal and Lukas Harzenetter and Frank Leymann and Vladimir Yussupov},
   title = {{Blockchain-based Collaborative Development of Application Deployment Models}},
   booktitle = {On the Move to Meaningful Internet Systems. OTM 2018 Conferences (CoopIS 2018)},
   publisher = {Springer International Publishing AG},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {11229},
   pages = {40--60},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2018},
   isbn = {978-3-030-02610-3},
   doi = {10.1007/978-3-030-02610-3_3},
   keywords = {Blockchains; Distributed Storage System; Collaborative Modeling; Declarative Software Deployment Models},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.4.1 Office Automation},
   contact = {Ghareeb Falazi: ghareeb.falazi@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {The automation of application deployment is vital today as manually deploying applications is too slow and error prone. For this reason, various deployment automation technologies have been developed that process deployment models to automatically deploy applications. However, in many scenarios, these deployment models have to be created in collaborative processes involving multiple participants that belong to independent organizations. For example, in data analytics scenarios, often external data scientists develop algorithms to process business-critical data of a company, while IT experts specify the technical infrastructure to deploy algorithms and data. However, as these deployment modeling processes are typically highly iterative and as the participating organizations may have competing interests, the degree of trust they have in each other is limited. Thus, without a guarantee of accountability, iterative collaborative deployment modeling is not possible in business critical domains. In this paper, we propose a decentralized approach that aims at achieving accountability in collaborative deployment modeling processes by utilizing public blockchains to store intermediate states of the collaborative deployment model in a way that guarantees its integrity and allows obtaining the history of changes it went through. The approach utilizes the same blockchain to establish the identity and authenticity of all participants of the process. We validate our approach by providing an architecture and a prototypical implementation of a blockchain-based deployment modeling environment based on the TOSCA standard.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2018-43&engl=0}
}
@inproceedings {INPROC-2018-40,
   author = {Michael Hahn and Uwe Breitenb{\"u}cher and Frank Leymann and Michael Wurster and Vladimir Yussupov},
   title = {{Modeling Data Transformations in Data-Aware Service Choreographies}},
   booktitle = {Proceedings of the IEEE 22nd International Enterprise Distributed Object Computing Conference (EDOC)},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {28--34},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2018},
   doi = {10.1109/EDOC.2018.00014},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     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 importance of data is steadily increasing in the domain of business process management due to recent advances in data science, IoT, and Big Data. To reflect this paradigm shift towards data-awareness in service choreographies, we introduced the notion of data-aware choreographies based on concepts for Transparent Data Exchange (TraDE) in our previous works. The goal is to simplify the modeling of business-relevant data and its exchange in choreography models while increasing their run time flexibility. To further improve and simplify the modeling of data-related aspects in service choreographies, in this paper, we focus on the extension of our TraDE concepts to support the modeling of data transformations in service choreographies. Such data transformation capabilities are of dire need to mediate between different data formats, structures and representations of the collaborating participants within service choreographies. Therefore, the paper presents a modeling extension as means for specifying and executing heterogeneous data transformations in service choreographies based on our TraDE concepts.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2018-40&engl=0}
}
@inproceedings {INPROC-2018-39,
   author = {Michael Hahn and Uwe Breitenb{\"u}cher and Frank Leymann and Vladimir Yussupov},
   title = {{Transparent Execution of Data Transformations in Data-Aware Service Choreographies}},
   booktitle = {On the Move to Meaningful Internet Systems. OTM 2018 Conferences (CoopIS 2018)},
   publisher = {Springer International Publishing AG},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {11230},
   pages = {117--137},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2018},
   isbn = {978-3-030-02671-4},
   doi = {10.1007/978-3-030-02671-4_7},
   keywords = {Data-aware Choreographies; Data Transformation; TraDE},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     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 = {Due to recent advances in data science, IoT, and Big Data, the importance of data is steadily increasing in the domain of business process management. Service choreographies provide means to model complex conversations between collaborating parties from a global viewpoint. However, the involved parties often rely on their own data formats. To still enable the interaction between them within choreographies, the underlying business data has to be transformed between the different data formats. The state-of-the-art in modeling such data transformations as additional tasks in choreography models is error-prone, time consuming and pollutes the models with functionality that is not relevant from a business perspective but technically required. As a first step to tackle these issues, we introduced in previous works a data transformation modeling extension for defining data transformations on the level of choreography models independent of their control flow as well as concrete technologies or tools. However, this modeling extension is not executable yet. Therefore, this paper presents an approach and a supporting integration middleware which enable to provide and execute data transformation implementations based on various technologies or tools in a generic and technology-independent manner to realize an end-to-end support for modeling and execution of data transformations in service choreographies.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2018-39&engl=0}
}
@inproceedings {INPROC-2018-36,
   author = {Vladimir Yussupov and Michael Falkenthal and Oliver Kopp and Frank Leymann and Michael Zimmermann},
   title = {{Secure Collaborative Development of Cloud Application Deployment Models}},
   booktitle = {Proceedings of The Twelfth International Conference on Emerging Security Information, Systems and Technologies (SECURWARE 2018)},
   editor = {Georg Yee and Stefan Rass and Stefan Schauer and Martin Latzenhofer},
   publisher = {Xpert Publishing Services},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {48--57},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2018},
   isbn = {9781612086613},
   language = {Englisch},
   cr-category = {D.2.11 Software Engineering Software Architectures,     D.4.6 Operating Systems Security and Protection},
   contact = {Vladimir Yussupov yussupov@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2018-36&engl=0}
}
@article {ART-2021-01,
   author = {Vladimir Yussupov and Jacopo Soldani and Uwe Breitenb{\"u}cher and Antonio Brogi and Frank Leymann},
   title = {{FaaSten your decisions: A classification framework and technology review of function-as-a-Service platforms}},
   journal = {Journal of Systems and Software},
   publisher = {Elsevier},
   volume = {175},
   type = {Artikel in Zeitschrift},
   month = {Mai},
   year = {2021},
   doi = {10.1016/j.jss.2021.110906},
   keywords = {Serverless; Function-as-a-Service; FaaS; Platform; Classification framework; Technology review},
   language = {Englisch},
   cr-category = {K.6 Management of Computing and Information Systems,     D.2.11 Software Engineering Software Architectures},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Function-as-a-Service (FaaS) is a cloud service model enabling developers to offload event-driven executable snippets of code. The execution and management of such functions becomes a FaaS provider{\^a}€™s responsibility, therein included their on-demand provisioning and automatic scaling. Key enablers for this cloud service model are FaaS platforms, e.g., AWS Lambda, Microsoft Azure Functions, or OpenFaaS. At the same time, the choice of the most appropriate FaaS platform for deploying and running a serverless application is not trivial, as various organizational and technical aspects have to be taken into account. In this work, we present (i) a FaaS platform classification framework derived using a multivocal review and (ii) a technology review of the ten most prominent FaaS platforms, based on the proposed classification framework. We also present a FaaS platform selection support system, called FaaStener, which can help researchers and practitioners to choose the FaaS platform most suited for their requirements.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2021-01&engl=0}
}
@article {ART-2019-19,
   author = {Vladimir Yussupov and Ghareeb Falazi and Michael Falkenthal and Frank Leymann},
   title = {{Protecting Deployment Models in Collaborative Cloud Application Development}},
   journal = {International Journal On Advances in Security},
   publisher = {IARIA},
   volume = {12},
   number = {1\&2},
   pages = {79--94},
   type = {Artikel in Zeitschrift},
   month = {Juni},
   year = {2019},
   issn = {1942-2636},
   keywords = {Collaboration; Security Policy; Confidentiality; Integrity; Deployment Model; Deployment Automation; TOSCA},
   language = {Englisch},
   cr-category = {D.2.11 Software Engineering Software Architectures,     D.4.6 Operating Systems Security and Protection},
   contact = {Vladimir Yussupov yussupov@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Profitability of industrial processes today depends on well-timed utilization of new technologies. Development of cloud applications combining cross-domain knowledge from multiple collaborating parties is one common way to enhance manufacturing. Often, such collaborations are not centralized due to outsourcing or rearrangements in organizational structures. Moreover, manual deployment inefficiency and intellectual property issues further tangle the development process of such applications. While the development of deployment models obviates the necessity to manually deploy applications, a way to protect sensitive data in exchanged deployment models is still needed. In this work, we describe the specifics of modeling and enforcement of security requirements for deployment models in the context of decentralized collaborative cloud application development. We provide a stepwise demonstration of how security requirements can be specified and enforced in a collaborative development scenario based on the TOSCA cloud standard. Furthermore, we conceptualize the system architecture, provide details about the implementation of certain approach-specific operations, and discuss the limitations of the approach. Finally, we show the feasibility of the presented concepts via an open-source prototype.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2019-19&engl=0}
}