270 research outputs found

    Discrete event simulation for the purpose of real-time performance evaluation of distributed hardware-in-the-loop simulators for autonomous driving vehicle validation

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    Hardware-in-the-loop test benches are distributed computer systems including software, hardware and networking devices, which require strict real-time guarantees. To guarantee strict real-time of the simulator the performance needs to be evaluated. To evaluate the timing performance a discrete event simulation model is built up. The input modeling is based on measurements from the real system in a prototype phase. The results of the simulation model are validated with measurements from a prototype of the real system. The workload is increased until the streaming source becomes unstable, by either exceeding a certain limit of bytes or exceeding the number of parallel software processes running on the cores of the central processing unit. To evaluate the performance beyond these limits, the discrete event simulation model needs to be enriched by a scheduler and a hardware model. To provide real-time guarantees an analytical model needs to be built up

    Ensuring Reliable and Predictable Behavior of IEEE 802.1CB Frame Replication and Elimination

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    Ultra-reliable and low-latency communication has received significant research attention. A key part of this evolution are the Time-Sensitive Networking (TSN) standards, which extend Ethernet with real-time mechanisms. To guarantee high reliability, the standard IEEE 802.1CB-2017 Frame Replication and Elimination for Reliability enables redundant communication over disjoint paths. While this mechanism is essential for time-critical applications, the standard contains some fundamental limitations that can compromise safety. Although some of these limitations have been addressed, none of the previous works provide solutions to these problems. This paper presents solutions to four main limitations of the IEEE 802.1CB-2017 standard. These are 1) choosing match versus vector recovery algorithm, 2) defining the length of the sequence history, 3) setting a timer to reset the sequence history, and 4) dimensioning the burst size in case of link failures. We show how these challenges can be solved by using best- and worst-case path delays of the network. We have performed simulations to illustrate the impact of the limitations and prove the correctness of our solutions. Thereby, we demonstrate how our solutions can improve reliability in TSN networks and propose these methods as guidance for users of the IEEE 802.1CB standard

    Spezifikation und Implementation des CAN-Arbitrierungsverfahrens in UPPAAL

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    In dieser Arbeit stellen wir eine durch Zeitautomaten modellierte Spezifikation des Mediumzugriffs im CAN-Protokoll vor sowie ihre Implementierung in UPPAAL. Zeitliche Anforderungen wurden dabei durch entsprechende Uhren-Nebenbedingungen erfasst. Dieses Zeitautomaten-Modell wurde anschließend automatisch verifiziert (Model Checking), wobei mehrere Anforderungen identifiziert wurden, die das CAN Protokoll erfüllen muß (wie Deadlock-Freiheit des Modells, Übertragungsrecht für die höchstpriore Nachricht, exklusives Übertragungsrecht für beliebigen CAN-Adapter nach der gewonnenen Arbitrage etc.). All diese Eigenschaften wurden in einer Variante der temporalen Logik CTL spezifiziert; die automatische Verifikation selbst wurde dabei mit UPPAAL durchgeführt, einem Model Checker für zeitautomaten-basierte Modelle

    From Simulation Data to Test Cases for Fully Automated Driving and ADAS

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    Part 3: Practical Applications International audience Within this paper we present a new concept on deriving test cases from simulation data and outline challenging tasks when testing and validating fully automated driving functions and Advanced Driver Assistance Systems (ADAS). Open questions on topics like virtual simulation and identification of relevant situations for consistent testing of fully automated vehicles are given. Well known criticality metrics are assessed and discussed with regard to their potential to test fully automated vehicles and ADAS. Upon our knowledge most of them are not applicable to identify relevant traffic situations which are of importance for fully automated driving and ADAS. To overcome this limitation, we present a concept including filtering and rating of potentially relevant situations. Identified situations are described in a formal, abstract and human readable way. Finally, a situation catalogue is built up and linked to system requirements to derive test cases using a Domain Specific Language (DSL). Document type: Part of book or chapter of boo

    A Service-Oriented Real-Time Communication Scheme for AUTOSAR Adaptive Using OPC UA and Time-Sensitive Networking

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    The transportation industry is facing major challenges that come along with innovative trends like autonomous driving. Due to the growing amount of network participants, smart sensors, and mixed-critical data, scalability and interoperability have become key factors of cost-efficient vehicle engineering. One solution to overcome these challenges is the AUTOSAR Adaptive software platform. Its service-oriented communication methodology allows a standardized data exchange that is not bound to a specific middleware protocol. OPC UA is a communication standard that is well-established in modern industrial automation. In addition to its Client–Server communication pattern, the newly released Publish–Subscribe (PubSub) architecture promotes scalability. PubSub is designed to work in conjunction with Time-Sensitive Networking (TSN), a collection of standards that add real-time aspects to standard Ethernet networks. TSN allows services with different requirements to share a single physical network. In this paper, we specify an integration approach of AUTOSAR Adaptive, OPC UA, and TSN. It combines the benefits of these three technologies to provide deterministic high-speed communication. Our main contribution is the architecture for the binding between Adaptive Platform and OPC UA. With a prototypical implementation, we prove that a combination of OPC UA Client–Server and PubSub qualifies as a middleware solution for service-oriented communication in AUTOSAR

    MMBnet 2017 - Proceedings of the 9th GI/ITG Workshop „Leistungs-, Verlässlichkeits- und Zuverlässigkeitsbewertung von Kommunikationsnetzen und Verteilten Systemen“

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    Nowadays, mathematical methods of systems and network monitoring, modeling, simulation, and performance, dependability and reliability analysis constitute the foundation of quantitative evaluation methods with regard to software-defined next-generation networks and advanced cloud computing systems. Considering the application of the underlying methodologies in engineering practice, these sophisticated techniques provide the basis in many different areas. The GI/ITG Technical Committee “Measurement, Modelling and Evaluation of Computing Systems“ (MMB) and its members have investigated corresponding research topics and initiated a series of MMB conferences and workshops over the last decades. Its 9th GI/ITG Workshop MMBnet 2017 „Leistungs-, Verlässlichkeits- und Zuverlässigkeitsbewertung von Kommunikationsnetzen und Verteilten Systemen“ was held at Hamburg University of Technology (TUHH), Germany, on September 14, 2017. The proceedings of MMBnet 2017 summarize the contributions of one invited talk and four contributed papers of young researchers. They deal with current research issues in next-generation networks, IP-based real-time communication systems, and new application architectures and intend to stimulate the reader‘s future research in these vital areas of modern information society

    Medien unter Kontrolle

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    This online publication summarizes mainly lectures of the same title that were given as a series at the Friedrich-Alexander University of Erlangen-Nuremberg in winter 2007/8. Most of the lecturers are members of the Center of Interdisciplinary Media Studies at the university. They represent the media related fields of book studies, classical archaeology, mass communication, christian communication, art history, multimedia didactics and drama. Thanks to these fields there is a big variety of media topics that are debated when it comes to media control. Instead of understanding media control simply as censorship, the productive effects of media control will also be broached, especially as they can be localized in the Arts. Focusing on the ethical responsibility in the media we will discuss furthermore the self-control of the media in Germany.Die vorliegende Online-Publikation fasst die Vorträge einer im WS 2007/08 gehaltenen Universitätsringvorlesung gleichen Titels an der Friedrich-Alexander-Universität Erlangen-Nürnberg zusammen und ergänzt sie durch nachträglich eingeworbene Beiträge. Die Ringvorlesung wie auch diese Publikation wurden organisiert vom Interdisziplinären Medienwissenschaftlichen Zentrum (IMZ), einem Forschungs- und Nachwuchsförderungsverbund der medienbezogenen Fächer an der Universität Erlangen-Nürnberg. Professorinnen und Professoren sowie NachwuchswissenschaftlerInnen der Fächer Buchwissenschaft, Christliche Publizistik, Christliche Archäologie, Klassische Archäologie, Kommunikationswissenschaft, Kunstgeschichte, Medienwissenschaft, Multimedia-Didaktik und Theaterwissenschaft forschen hierin selbstorganisiert an den Schnittstellen fächerübergreifend relevanter Fragestellungen der Medientheorie, -praxis, -ethik und -didaktik und führen auch den jeweiligen wissenschaftlichen Nachwuchs frühzeitig an entsprechende interdisziplinäre Arbeitsfelder heran. Der Zusammenschluss trägt dem Umstand Rechnung, dass Medien inzwischen ein primäres Bezugsfeld vieler Disziplinen darstellen, die aus je eigener Perspektive Fragen nach den Funktionen, Verwendungshinsichten, möglichen Wirkungen und Entwicklungstendenzen von Medien in einer sich immer stärker als Medien- und Kommunikationsgesellschaft verstehenden Gesellschaft generieren. Einen Überblick über Zusammensetzung und Aktivitäten des IMZ bietet die Homepage unter http://www.imz.uni-erlangen.de
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