@inproceedings{DBLP:conf/icse/0001OG19,
title = {Modeling semantic dependencies to allow flow monitoring in networks  with black-box nodes},
author = {Stefan Gries and 
 Julius Ollesch and 
 Volker Gruhn},
url = {https://doi.org/10.1109/SEsCPS.2019.00010},
doi = {10.1109/SEsCPS.2019.00010},
year  = {2019},
date = {2019-01-01},
booktitle = {Proceedings of the 5th International Workshop on Software Engineering for Smart Cyber-Physical Systems, SEsCPS@ICSE 2019, Montreal, QC, 
 Canada, May 28, 2019},
pages = {14--17},
crossref = {DBLP:conf/icse/2019sescps},
keywords = {CPS, Cyber-Physical Systems},
pubstate = {published},
tppubtype = {inproceedings}
}
@inproceedings{8416426,
title = {Embedding Non-Compliant Nodes into the Information Flow Monitor by Dependency Modeling},
author = {S. Gries and M. Hesenius and V. Gruhn},
doi = {10.1109/ICDCS.2018.00163},
year  = {2018},
date = {2018-07-01},
booktitle = {2018 IEEE 38th International Conference on Distributed Computing Systems (ICDCS)},
pages = {1541-1542},
abstract = {Observing semantic dependencies in large and heterogeneous networks is a critical task, since it is quite difficult to find the actual source of a malfunction in the case of an error. Dependencies might exist between many network nodes and among multiple hops in paths. If those dependency structures are unknown, debugging errors gets quite difficult. Since CPS and other large networks change at runtime and consists of custom software and hardware, as well as components off-the-shelf, it is necessary to be able to not only include own components in approaches to detect dependencies between nodes. In this paper we present an extension to the Information Flow Monitor approach. Our goal is that this approach should be able to handle unalterable blackbox nodes. This is quite challenging, since the IFM originally requires each network node to be compliant with the IFM protocol.},
keywords = {Conferences;Distributed computing;Monitoring;cps;cyber physical systems;dependency modeling;information flow monitor;semantic dependencies},
pubstate = {published},
tppubtype = {inproceedings}
}
@inproceedings{8416429,
title = {Developing a Convenient and Fast to Deploy Simulation Environment for Cyber-Physical Systems},
author = {S. Gries and O. Meyer and J. Ollesch and F. Wessling and M. Hesenius and V. Gruhn},
doi = {10.1109/ICDCS.2018.00166},
year  = {2018},
date = {2018-07-01},
booktitle = {2018 IEEE 38th International Conference on Distributed Computing Systems (ICDCS)},
pages = {1551-1552},
abstract = {Cyber-Physical Systems (CPS) are interconnected systems, that adapt to their environment. They are quite challenging to engineer and to test, because the its interconnected and networked structures changes at runtime. Dependencies and influencing between nodes in the network might be difficult to test, because there are many hidden impacts on not directly connected nodes. In this paper, we present our experimentation environment which we use to simulate different CPSs. The focus of the development of this environment is to be able to rapidly generate, deploy and change software and network connections within the CPS and to observe resulting impacts on the network.},
keywords = {Actuators;Generators;Network topology;Software;Temperature sensors;Topology;air quality;cps;cyber-physical systems;simulation;software engineering process},
pubstate = {published},
tppubtype = {inproceedings}
}
@inproceedings{DBLP:conf/ecsa/MeyerH0WG18,
title = {A decentralized architecture and simple consensus algorithm for autonomous  agents},
author = {Ole Meyer and 
 Marc Hesenius and 
 Stefan Gries and 
 Florian Wessling and 
 Volker Gruhn},
url = {https://doi.org/10.1145/3241403.3241413},
doi = {10.1145/3241403.3241413},
year  = {2018},
date = {2018-01-01},
booktitle = {Proceedings of the 12th European Conference on Software Architecture: 
 Companion Proceedings, ECSA 2018, Madrid, Spain, September 24-28, 
 2018},
pages = {7:1--7:4},
crossref = {DBLP:conf/ecsa/2018c},
keywords = {CPS, Cyber-Physical Systems},
pubstate = {published},
tppubtype = {inproceedings}
}
@inproceedings{DBLP:conf/somet/0001MOWHG18,
title = {Developing a Cyber-Physical Autonomous and Distributed Intersection  Management - A Software Engineer's Experience Report},
author = {Stefan Gries and 
 Ole Meyer and 
 Julius Ollesch and 
 Florian Wessling and 
 Marc Hesenius and 
 Volker Gruhn},
url = {https://doi.org/10.3233/978-1-61499-900-3-582},
doi = {10.3233/978-1-61499-900-3-582},
year  = {2018},
date = {2018-01-01},
booktitle = {New Trends in Intelligent Software Methodologies, Tools and Techniques 
 - Proceedings of the 17th International Conference SoMeT_18, Granada, 
 Spain, 26-28 September 2018},
pages = {582--595},
crossref = {DBLP:conf/somet/2018},
keywords = {CPS, Cyber-Physical Systems},
pubstate = {published},
tppubtype = {inproceedings}
}
@inproceedings{DBLP:conf/icsa/0001MWHG18,
title = {Using Blockchain Technology to Ensure Trustful Information Flow Monitoring  in CPS},
author = {Stefan Gries and 
 Ole Meyer and 
 Florian Wessling and 
 Marc Hesenius and 
 Volker Gruhn},
url = {https://doi.org/10.1109/ICSA-C.2018.00014},
doi = {10.1109/ICSA-C.2018.00014},
year  = {2018},
date = {2018-01-01},
booktitle = {2018 IEEE International Conference on Software Architecture Companion, 
 ICSA Companion 2018, Seattle, WA, USA, April 30 - May 4, 2018},
pages = {35--38},
crossref = {DBLP:conf/icsa/2018c},
keywords = {Blockchain, CPS, Cyber-Physical Systems},
pubstate = {published},
tppubtype = {inproceedings}
}
@inproceedings{DBLP:conf/somet/Gruhn0HORSWW17,
title = {Engineering Cyber-Physical Systems},
author = {Volker Gruhn and Stefan Gries and Marc Hesenius and Julius Ollesch and Shafiq - and Nils Schwenzfeier and Christian Wahl and Florian Wessling},
url = {https://doi.org/10.3233/978-1-61499-800-6-3},
doi = {10.3233/978-1-61499-800-6-3},
year  = {2017},
date = {2017-09-26},
booktitle = {New Trends in Intelligent Software Methodologies, Tools and Techniques 
 - Proceedings of the 16th International Conference, SoMeT_17, Kitakyushu 
 City, Japan, September 26-28, 2017},
pages = {3--18},
crossref = {DBLP:conf/somet/2017},
abstract = {Connecting digital information systems with real world objects and processes is the core of the digital transformation. New business models and opportunities thrive on the various options that the resulting information offers. Cyber-Physical Systems (CPS) are the most prominent incarnation and – in contrast to various other aspects of the digital transformation – really new: sensors and actors allow information systems to monitor the real world and will profoundly change most markets and business domains. However, developing CPS involves different specialists and various technical challenges. Software and hardware engineers, network specialists, and data scientists have to work hand in hand and combine their specialties to incorporate the different perspectives into one team. We present EngCPS, an engineering approach to develop CPS that enhances classic software engineering methods with CPS-specific extensions.},
keywords = {CPS, Cyber-Physical Systems},
pubstate = {published},
tppubtype = {inproceedings}
}
@inproceedings{DBLP:conf/somet/0001HG17,
title = {Tracing Cascading Data Corruption in CPS with the Information Flow  Monitor},
author = {Stefan Gries and Marc Hesenius and Volker Gruhn},
url = {https://doi.org/10.3233/978-1-61499-800-6-399},
doi = {10.3233/978-1-61499-800-6-399},
year  = {2017},
date = {2017-09-11},
booktitle = {New Trends in Intelligent Software Methodologies, Tools and Techniques 
 - Proceedings of the 16th International Conference, SoMeT_17, Kitakyushu 
 City, Japan, September 26-28, 2017},
pages = {399--408},
crossref = {DBLP:conf/somet/2017},
abstract = {Cyber-physical systems are context-aware networked systems containing sensors, aggregators and actuators. Raw sensor data and aggregated information are spread among the network and processed in multiple nodes to result in an action, which is possibly executed at a different physical location in the network. Due to the flexible topology and the emergent features of CPS, decisions within the network that trigger actions are not always trivial to understand. These decisions are based on raw sensor data which are not clearly visible at the location of their execution. This can be problematic if decisions have to be justifiable. It becomes even more difficult if decisions has been flawed, and it is not ascertainable why they were made. In order to determine the reasons for incorrect decisions in the network, the dependencies and input values of a decision must be known. Without this information, debugging is quite difficult. In this paper, we present the Information Flow Monitor, which can capture and visualize dependencies between nodes and information in CPS.},
keywords = {cascading data corruption, CPS, Cyber-Phyiscal System, Cyber-Physical Systems, Data Tracking, flow monitoring, IFM, information dependencies, Information Flow Monitor, Internet of Things},
pubstate = {published},
tppubtype = {inproceedings}
}
@inproceedings{Meyer:2017:PRC:3093742.3096475,
title = {Property-based Routing in Clustered Message Brokers for CPS},
author = { Ole Meyer and Julius Ollesch and Stefan Gries and Florian Wessling and Volker Gruhn},
url = {http://doi.acm.org/10.1145/3093742.3096475},
doi = {10.1145/3093742.3096475},
isbn = {978-1-4503-5065-5},
year  = {2017},
date = {2017-06-19},
booktitle = {Proceedings of the 11th ACM International Conference on Distributed and Event-based Systems},
pages = {366--369},
publisher = {ACM},
address = {Barcelona, Spain},
series = {DEBS '17},
abstract = {Cyber-Physical Systems (CPS) are interconnected systems that can measure, manipulate, and adapt their environment via sensors and actors. The high number of measured data means that a reliable and scalable communication infrastructure is indispensable, especially if data is processed in real time. Data can be available in different measurement qualities, which usability depends on the particular application. As a result, data is regularly discarded, resulting in network inefficiencies when they are previously transmitted. This effect becomes more important as the number of heterogeneous sensors increases. In this paper, we discuss the implications and show our first approach to solve the problem based on MQTT [1], one of the most widely used public-subscribe protocols in the area of IoT and CPS.},
keywords = {clustering, CPS, Cyber-Physical Systems, efficiency, Internet of Things, MQTT, publish-subscribe, routing, simulation, world-scale},
pubstate = {published},
tppubtype = {inproceedings}
}
@inproceedings{Gries:2017:CDC:3093742.3095092,
title = {Cascading Data Corruption: About Dependencies in Cyber-Physical Systems},
author = { Stefan Gries and Marc Hesenius and Volker Gruhn},
url = {http://doi.acm.org/10.1145/3093742.3095092},
doi = {10.1145/3093742.3095092},
isbn = {978-1-4503-5065-5},
year  = {2017},
date = {2017-06-01},
booktitle = {Proceedings of the 11th ACM International Conference on Distributed and Event-based Systems},
pages = {345--346},
publisher = {ACM},
address = {Barcelona, Spain},
series = {DEBS '17},
abstract = {CPS are interconnected systems that observe and manipulate real objects and processes. They allow dynamic extension and show emergent behavior which leads to dynamic decision-making processes that can change at runtime. They cannot always be easily understood because of the high number of components involved. If an error occurs in such a process, it is difficult to comprehend which component involved in the decision process is responsible for that error. The decision therefore has a high degree of dependency on the nodes involved in the process. Therefore, errors are not easily traceable to their original source. In this paper, we present the idea of dependency trees, which should help to identify error sources in the event of a fault.},
keywords = {cascading data corruption, Cascading Data Curroption, cascading failures, CPS, Cyber-Phyiscal System, Cyber-Physical Systems, flow monitoring, information dependencies},
pubstate = {published},
tppubtype = {inproceedings}
}
@inproceedings{7980245,
title = {Tracking Information Flow in Cyber-Physical Systems},
author = {S. Gries and M. Hesenius and V. Gruhn},
url = {http://ieeexplore.ieee.org/document/7980245/},
doi = {10.1109/ICDCS.2017.116},
issn = {1063-6927},
year  = {2017},
date = {2017-06-01},
booktitle = {2017 IEEE 37th International Conference on Distributed Computing Systems (ICDCS)},
pages = {2589-2590},
abstract = {Cyber-Physical Systems are distributed, heterogeneous, decentralized and loosely coupled networks in which individual systems measure physical processes, exchange information, and influence processes. Sensors measure these physical processes, while aggregators process them and actuators perform resulting actions. Decisions are often based on sensor data collected by other systems. Furthermore, the aggregators also interchange information and use them to derive own decisions. Decisions must be comprehensible. However, this is only the case if all data dependencies are known. Due to the size of these networks, their loose coupling and their dynamic behavior, decisions made by a system are not always easy to understand. If an error occurs in the system, the error source must be identified. It must be known on which data a decision was based. However, since the decision can be based on information from other nodes, the search for the error source is not a trivial task. Keep in mind, that dependent nodes can have dependencies themselves as well. We present the Information Flow Monitor (IFM) that collects information about semantic data dependencies in dynamic networks. The collected dependency information is provided at a central network location. Subsequently, semantic dependencies between information can be visualized.},
keywords = {Actuators, CPS, Cyber-Physical Systems, Data Tracking, History, IFM, Information Flow Monitor, Monitoring, Protocols, Semantic Dependencies, Semantics, Sensors},
pubstate = {published},
tppubtype = {inproceedings}
}
@inbook{Wessling2017,
title = {Engineering a Cyber-Physical Intersection Management -- An Experience Report},
author = {Florian Wessling
and Stefan Gries
and Julius Ollesch
and Marc Hesenius
and Volker Gruhn},
editor = {Andreas Braun
and Reiner Wichert
and Antonio Mana},
url = {http://dx.doi.org/10.1007/978-3-319-56997-0_2},
doi = {10.1007/978-3-319-56997-0_2},
isbn = {978-3-319-56997-0},
year  = {2017},
date = {2017-04-05},
booktitle = {Ambient Intelligence: 13th European Conference, AmI 2017, Malaga, Spain, April 26--28, 2017, Proceedings},
pages = {17--32},
publisher = {Springer International Publishing},
address = {Cham},
abstract = {The engineering of cyber-physical systems (CPS) imposes a huge challenge for today’s software engineering processes. Not only are CPS very closely related to real objects and processes, also their internal structures are more heterogeneous than classical information systems. In this experience report, we account on a prototypical implementation for an intersection management system on the basis of physical models in the form of robotic cars. The steps to implement the working physical prototype are described. Lessons learned during the implementation are presented and observations compared against known software processes. The insights gained are consolidated into the novel Double Twin Peaks model. The latter extends the current software engineering viewpoints, specifically taking CPS considerations into account.},
keywords = {CPS, Cyber-Physical Systems},
pubstate = {published},
tppubtype = {inbook}
}
@article{kerntechnologien-cascadingdatacorruption,
title = {Cyber-Physical Systems: Cascading Data Corruption - Kaskadierende Fehler in verteilten und heterogenen Netzwerken},
author = {Gries, Stefan and Gruhn, Volker and Hesenius, Marc and Ollesch, Julius},
url = {https://cps-hub-nrw.de/knowledgebase/publikation/3609-cascading-data-corruption
https://stefan.gries.nrw/wp-content/uploads/2017/03/Cascading_Data_Corruption_CPS.HUB_.pdf},
year  = {2017},
date = {2017-02-20},
abstract = {Durch die Weitergabe von Informationen im Netzwerk entstehen Abhängigkeiten zwischen den einzelnen Knoten. Entscheidungen eines Aggregators beruhen nicht mehr nur auf eigenen Daten, sondern auch auf Sensorwerten von entfernen Netzwerk-Knoten. Die durch den Aktor ausgeführte Aktion ist seinerseits also nicht nur von einem (oder mehreren) steuernden Knoten abhängig, sondern ebenfalls von deren Datenlieferanten. Es entsteht ein Abhängigkeitsbaum, der beliebig viele Ebenen enthalten kann. An Aktoren sichtbar werdende Entscheidungen können daher oft nicht nachvollziehbar wirken, da der Abhängigkeitsbaum in der Regel nicht bekannt nicht einfach konstruierbar oder ableitbar ist. Um Abhängigkeiten in Netzwerken im Bezug zur Semantik zu erfassen und nachzuverfolgen wurden bisher wenige Arbeiten veröffentlicht. Soweit uns bekannt, hat noch keine andere Forschungsgruppe zu dem Thema, wie semantische Abhängigkeiten zwischen ausgetauschten Nachrichten in verteilten Netz-werken erfasst werden können, veröffentlicht. },
keywords = {Cascading Data Curroption, CPS, Cyber-Physical Systems},
pubstate = {published},
tppubtype = {article}
}
@misc{fachgruppentreffen_datatracking,
title = {Data Tracking in Cyber -Physical Systems: Probleme, Perspektiven und Lösungsansätze},
author = {Gries, Stefan},
url = {https://cps-hub-nrw.de/news/2016-10-20-daten-als-rohstoff-der-digitalisierung-1
https://stefan.gries.nrw/wp-content/uploads/2017/02/DataTracking_SGR.pdf},
year  = {2016},
date = {2016-10-18},
abstract = {Stefan Gries, paluno / Universität Duisburg-Essen, machte auf die Herausforderung aufmerksam, dass vernetzte Systeme, die Sensordaten verarbeiten, deutlich schwieriger zu warten sind als klassische Informationssysteme. Durch mehrfache Verarbeitung und Weitergabe von Daten ist es eine Herausforderung, die eigentliche Fehlerquelle zu identifizieren, wenn ein Fehler auftritt. Er stellte das Konzept des „Information Flow Monitors“ vor, einem Forschungsvorhaben, das zukünftig Betreiber von CPS bei der Ursachenanalyse unterstützen soll.},
keywords = {CPS, Cyber-Physical Systems},
pubstate = {published},
tppubtype = {presentation}
}
@article{kerntechnologien-topologien,
title = {Cyber-Physical Systems: Topologien - Strukturelle Anforderungen an verteilte CPS},
author = {Gries, Stefan and Gruhn, Volker and Hesenius, Marc and Ollesch, Julius},
url = {https://cps-hub-nrw.de/knowledgebase/publikation/3511-topologien
https://stefan.gries.nrw/wp-content/uploads/2017/02/Topologien_CPS.HUB_.pdf},
year  = {2016},
date = {2016-06-02},
abstract = {Netzwerke bestehen auch bei cyber-physikalischen Systemen aus einer Menge an miteinander verbundenen Systemen, bei denen jedes einzelne im Gesamtsystem eingefügte System einen Teil zur Gesamtfunktion des CPS beiträgt. Viele Charakteristiken von CPS spiegeln sich auch in ihrer strukturellen Zusammensetzung, also der Topologie des Gesamtsystems, wider. Einige Eigenschaften, beispielsweise Abhängigkeiten, Hierarchiebeziehungen oder Topologie, die auch Funktion und Verhalten des Systems beeinflusst, entstehen durch das Zusammenspiel der einzelnen Subsysteme und deren strukturellen Verbindungen zueinander. Die Topologie eines Power Transmission Network hat so beispielsweise direkten Einfluss auf die Robustheit und Stabilität der Stromübertragung. Die Wahl der Netztopologie hat in diesem Bereich enorme Auswirkungen auf die Aspekte Sicherheit, Stabilität, Leistungsfähigkeit und Performance und spielt somit in wesentlichen Aspekten der CPS Entwicklung eine entscheidende Rolle. Auch der Bereich der Connected Cars ist von den Auswirkungen unterschiedlicher Topologien betroffen. Hierbei stehen dem Auto unterschiedliche Dienste und Kommunikationspartner zur Verfügung, die über unterschiedliche Wege erreicht werden können. Konkret gibt es hier die Möglichkeit der direkten Car-to-Car Kommunikation und der Abwicklung der Kommunikation über zentrale Dienste. },
keywords = {CPS, Cyber-Physical Systems, Topologien},
pubstate = {published},
tppubtype = {article}
}
@article{kerntechnologien-mobilenetzwerke,
title = {Cyber-Physical Systems: Mobile Netzwerke - Herausforderungen bzgl. Vernetzung in heterogenen CPS},
author = {Gries, Stefan and Gruhn, Volker and Hesenius, Marc and Ollesch, Julius},
url = {https://cps-hub-nrw.de/knowledgebase/publikation/3510-mobile-netzwerke
https://stefan.gries.nrw/wp-content/uploads/2017/02/Mobile_Networks_CPS.HUB_.pdf},
year  = {2016},
date = {2016-06-02},
abstract = {Während für die Infrastruktur von Connected Car-Systemen, wie etwa bei Verkehrsüberwachungssystemen oder anderen fest installierte Smart-Devices, die Möglichkeit besteht über herkömmliche kabelgebundene Local Area Networks (LAN) zu kommunizieren, besteht diese nicht für bewegliche Systemteilnehmer wie das Connected Car selbst. Mobile Verkehrsteilnehmer sind auf eine zuverlässige, drahtlose Kommunikationsmöglichkeit angewiesen und können ihre Anforderungen nur dann korrekt erfüllen, wenn die drahtlose Kommunikation robust und sicher abläuft. Hierdurch werden bestimmte CPS, wie beispielsweise Connected-Car-Systeme oder Smart-Energy-Grids, erst durch mobile Netze ermöglicht. Auch in anderen Anwendungsbereichen, die mit sogenannten mobilen bzw. beweglichen Smart-Devices arbeiten, kommen herkömmliche kabelgebundene LANs nicht in Frage. Dies ist insbesondere auch für mobile Sensorik, Smartphones oder andere Geräte der Fall. Auch Brachengrößen wie Intel haben die Bedeutung der mobilen Netze im CPS- und IoT-Kontext (Internet of Things) erkannt und bieten spezielle Kommunikationslösungen und Gateways an, die für Applikationen genutzt werden können. Gateways erlauben hierbei den Anschluss von Hardware an IoT- und CPS-Plattformen und bestehenden Geräten die Kommunikation mit einer Cloud-Infrastruktur.},
keywords = {CPS, Cyber-Physical Systems, Mobile Netzwerke},
pubstate = {published},
tppubtype = {article}
}
@inproceedings{Hesenius:2014:AUT:2628363.2628391,
title = {Automating UI Tests for Mobile Applications with Formal Gesture Descriptions},
author = {Hesenius, Marc and Griebe, Tobias and Gries, Stefan and Gruhn, Volker},
url = {http://doi.acm.org/10.1145/2628363.2628391},
doi = {10.1145/2628363.2628391},
isbn = {978-1-4503-3004-6},
year  = {2014},
date = {2014-01-01},
booktitle = {Proceedings of the 16th International Conference on Human-computer Interaction with Mobile Devices & Services},
pages = {213--222},
publisher = {ACM},
address = {Toronto, ON, Canada},
series = {MobileHCI '14},
abstract = {Touch- and gesture-based interfaces are common in applications for mobile devices. By evolving into mass market products, smartphones and tablets created an increased need for specialized software engineering methods. To ensure high quality applications, constant and efficient testing is crucial in software development. However, testing mobile applications is still cumbersome, time-consuming and error-prone. One reason is the devices' focus on touch-based interaction - gestures cannot be easily incorporated into automated application tests. We present an extension to the popular Calabash testing framework solving this problem by allowing to describe gestures with a formal language in tests scripts.},
keywords = {gesture formalization, gestures, mobile applications, software engineering, test automation, testing},
pubstate = {published},
tppubtype = {inproceedings}
}