Dr. rer. nat.

Weiß, Gereon

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  • Publication
    SafeAdapt - safe adaptive software for fully electric vehicles
    ( 2014)
    Schleiß, Philipp
    ;
    Zeller, Marc
    ;
    Weiß, Gereon
    ;
    Eilers, Dirk
    The promising advent of Fully Electric Vehicles (FEVs) also induces a shift towards fully electronic control of existing and new vehicle functions. Hereby, critical functions, such as Brake- and Steer-by-Wire, require sophisticated redundancy solutions to ensure safety. As a result, the overall electric/electronic (E/E) architecture of a vehicle is becoming even more complex and costly. To address the need for safety, reliability and cost efficiency in future FEVs, the development of a novel adaptive architecture to manage complexity through generic, adaptive, and system-wide fault handling is essential. Moreover, to enable this transition, design simplicity, cost efficiency, and energy consumption are especially important elements. Consequently, the SafeAdapt project seeks a holistic approach by comprising the methods, tools, and building blocks needed to design, develop and certify such safety-critical systems for the e-vehicle domain. In detail, a platform core encapsulating the basic adaptation mechanisms for relocating and updating functionalities is developed on basis of AUTOSAR. It serves as foundation for an interoperable and standardised solution for adaptation and fault handling in upcoming automotive networked control systems. In particular, emphasis is laid on functional safety with respect to the ISO26262 standard, wherefore an integrated approach ranging from tool chain support, reference architectures, modelling of system design and networking, up to early validation and verification is derived. To realistically validate these adaptation and redundancy concepts, an e-vehicle prototype with different and partly redundant applications is being developed. Moreover, the presented work outlines the motivation and challenges of future E/E architectures and contributes a technical strategy to overcome those hindrances.
  • Publication
    Towards runtime adaptation in AUTOSAR
    ( 2013)
    Zeller, Marc
    ;
    Prehofer, Christian
    ;
    Krefft, Daniel
    ;
    Weiß, Gereon
    In many industrial application domains networked embedded systems realize safety-critical applications. In such systems, adapting the software distribution at runtime can be used to optimize system configurations, to add new features or to handle failure cases. The main objective of this paper is to devise a flexible and efficient solution for runtime adaptation in AUTOSAR, which requires minimal changes to the current architecture. We elaborate the main challenges for extending AUTOSAR and argue that small changes in the architecture and design process are feasible and effective for this purpose. Our work is validated by a proof of concept implementation.
  • Publication
    Verifying & validating non-functional properties of automotive software architectures in early design stages
    ( 2013)
    Stante, Alexander
    ;
    Kamphausen, Benjamin
    ;
    Zeller, Marc
    ;
    Weiß, Gereon
    An increasing number of functions in modern automobiles are software-based. A modern automotive architecture contains up to 100 electronic control units (ECU) that communicate with one another to ensure proper vehicle functionality. The requirements and the set of provided functionalities of automotive embedded systems are growing, the complexity of these systems is continuously increasing as well. Early verification of automotive software architectures is necessary to prevent failures and to save costs during the design. Considering solely functional properties of the software for networked embedded systems is insufficient to satisfy the quality requirements in the automotive domain. To produce robust software-based embedded systems in a cost-efficient way, an early verification of non-functional properties is inevitable. Based on a specific simulation framework, written in SystemC, the open tool-chain framework ERNEST provides flexible mechanisms to verify non-functional properties of component-based software systems in early design stages. ERNEST can be integrated easily into a model-based design flow and is based on the open-source development platform Eclipse. Thus, it states an extensible tool platform for verifying non-functional properties, which can easily be enhanced by various analysis techniques.
  • Publication
    ERNEST - framework for the early verification and validation of networked embedded systems
    ( 2013)
    Kamphausen, Benjamin
    ;
    Stante, Alexander
    ;
    Zeller, Marc
    ;
    Weiß, Gereon
    Since the requirements and the set of provided functionalities of networked embedded systems are growing, the complexity of these systems is continuously increasing as well. Early verification of embedded systems is necessary to prevent failures and to save costs during the design. Considering solely functional properties of the software for networked embedded systems is insufficient to satisfy the quality requirements in most of their application domains. To produce robust software-based embedded systems in a cost-efficient way, an early verification of non-functional properties is inevitable. ERNEST is an open tool-chain framework to enable the early verification of component-based software in the area of networked embedded systems. Based on a specific simulation framework, written in SystemC, ERNEST provides flexible mechanisms to verify non-functional properties in early design stages. ERNEST can be integrated easily into a model-based design flow and is based on the open-source development platform Eclipse. Thus, it states an extensible tool platform for verifying non-functional properties, which can easily be enhanced by various analysis techniques. To analyze and verify a networked embedded system, the modeled hardware, software and communication behavior is simulated as accurate as needed. The results of these simulations can be used in third-party tools or re-integrated into the initial model. Thus, an iterative model-driven development exploiting early prototyping is possible.
  • Publication
    Towards runtime adaptation in AUTOSAR
    ( 2013)
    Zeller, Marc
    ;
    Prehofer, Christian
    ;
    Krefft, Daniel
    ;
    Weiß, Gereon
    In many industrial application domains networked embedded systems realize safety-critical applications. In such systems, adapting the software distribution at runtime can be used to optimize system configurations, to add new features or to handle failure cases. The main objective of this paper is to devise a flexible and efficient solution for runtime adaptation in AUTOSAR, which requires minimal changes to the current architecture. We elaborate the main challenges for extending AUTOSAR and argue that small changes in the architecture and design process are feasible and effective for this purpose. Our work is validated by a proof of concept implementation.
  • Publication
    Interface verification using executable reference models: An application in the automotive infotainment
    ( 2013)
    Drabek, Christian
    ;
    Pramsohler, Thomas
    ;
    Zeller, Marc
    ;
    Weiß, Gereon
    Modern in-vehicle infotainment systems comprise highly interactive software components. The verification of the interfaces of such components poses a major challenge for developers. In this work, we present an approach for model-based verification of distributed infotainment components. We define a layered reference model which specifies the interaction between two components at syntactical and behavioral level. The layers abstract from the used middleware so developers may focus on the components' actual interface behavior. Additionally, we define a model execution framework which enables the reuse of the reference model for verification of interface implementations. We demonstrate the applicability of the approach using an industrial case study. Our approach aims at reducing errors in the communication behavior and increasing the overall product quality.
  • Publication
    Modellbasierte Validierung von Infotainment-Funktionen im Auto
    ( 2012)
    Paulic, A.
    ;
    Zeller, Marc
    ;
    Weiß, Gereon
    ;
    Eilers, Dirk
    Bei der Kaufentscheidung für ein Auto werden Infotainment- und Multimedia-Anwendungen immer wichtiger. Die Netzwektechnologie Media Oriented Systems Transport (MOST) ist derzeit Standard für automobile Infotainment-Systeme und ermöglicht anspruchsvolles Infotainment im Auto. Die zunehmende Komplexität und Interaktion dieser Funktionen ist eine große Herausforderung bei der Entwicklung. Die Qualität der Systeme muss bei stetig zunehmender Funktionalität gewährleistet sein, zudem soll die Entwicklung immer günstiger werden. Hierzu wird modellbasierte Softwareentwicklung bereits erfolgreich eingesetzt. In dieser Arbeit haben wir neue Konzepte zur modellbasierten Validierung von Infotainment-Funktionen entwickelt und umgesetzt. Dabei wurden sog. Referenzmodelle als ausführbare Spezifikationen eingeführt und zur Validierung wiederverwendet.
  • Publication
    Towards efficient on-line schedulability tests for adaptive networked embedded real-time systems
    ( 2012)
    Becker, Klaus
    ;
    Zeller, Marc
    ;
    Weiß, Gereon
    In networked embedded systems, runtime adaptive software promises an increase of flexibility, fault tolerance and extensibility. Often, this requires that software components have to be allocated dynamically to execution platforms at runtime. Hence, the platforms have to execute dynamically changing task sets. However, in real-time systems, a task set cannot be executes without previously checking its schedulability w.r.t. given timing constraints. Therefore, it has to be determined, whether or not the existing task set would be still schedulable including newly arriving tasks. In this paper, we propose a schedulability test algorithm for such systems, exploiting the situation of adding a new task to an existing task set. Therefore, we adapt existing schedulability tests to exploit the specific acceptance test use case. The benefits of the developed adaptations are shown by experimental investigations.
  • Publication
    Modellbasierte Erkennung von Fehlverhalten
    ( 2012)
    Paulic, Annette
    ;
    Pramsohler, Thomas
    ;
    Kaule, Dirk
    ;
    Zeller, Marc
    ;
    Weiß, Gereon
    Die vorgestellten Konzepte zur modellbasierten Verifikation von Infotainment-Funktionen im Automobil zeigen, wie modellbasierte Verfahren bei der Fehlersuche unterstützen können. Mithilfe der von der Fraunhofer ESK in Zusammenarbeit mit der BMW Forschung und Technik GmbH erforschten Methodik zur modellbasierten Verifikation ist es möglich, implementierte Infotainment-Funktionen mit ihrer Spezifikation zu vergleichen und Abweichungen an der MOST Schnittstelle zuverlässig zu erkennen. Grundlage hierfür bilden der Funktionskatalog und das Zustandsdiagramm des MOST Funktionsblocks. Ein großer Vorteil ist, dass diese Modelle, die bereits jetzt zur Spezifikation eingesetzt werden, auch zur Absicherung verwendet werden können. Die Transformation der Modelle erfolgt dabei automatisiert.
  • Publication
    Approach for iterative validation of automotive embedded systems
    ( 2010)
    Weiß, Gereon
    ;
    Zeller, Marc
    ;
    Eilers, D.
    ;
    Knorr, Rudi
    Architecture description languages (ADLs) allow specifying system information in architecture models. These are generally used for capturing early design decisions concerning system or software development. Therefore, ADLs can be utilized for an early and iterative validation of the modelled system. With EAST-ADL an automotive specific ADL is defined which allows describing an automotive system at different layers of abstraction targeting AUTOSAR systems. SystemC is an executable system modelling and simulation language which permits Hardware/Software-Co-Design. With the Transaction-Level Modeling (TLM) methodology the description of different layers of abstraction in SystemC is enabled. This work addresses the early validation of automobile electronic systems by providing a transformation of EAST-ADL models to SystemC at different layers of abstraction. This allows specific analysis with Hardware/Software Co-Simulation iteratively in the development process. The proposed approach is realized in a tool-chain and demonstrated by a typical automotive use case. Hence, we show the potential of an early validation of system and software designs based on architecture models.