Dr. rer. nat.

Weiß, Gereon

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  • Publication
    Generic management of availability in fail-operational automotive systems
    ( 2017)
    Schleiß, Philipp
    ;
    Drabek, Christian
    ;
    Weiß, Gereon
    ;
    Bauer, Bernhard
    The availability of functionality is a crucial aspect of mission- and safety-critical systems. This is for instance demonstrated by the pursuit to automate road transportation. Here, the driver is not obligated to be part of the control loop, thereby requiring the underlying system to remain operational even after a critical component failure. Advances in the field of mixed-criticality research have allowed to address this topic of fail-operational system behaviour more efficiently. For instance, general purpose computing platforms may relinquish the need for dedicated backup units, as their purpose can be redefined at runtime. Based on this, a deterministic and resource-efficient reconfiguration mechanism is developed, in order to address safety concerns with respect to availability in a generic manner. To find a configuration for this mechanism that can ensure all availability-related safety properties, a design-time method to automatically generate schedules for different modes of operations from declaratively defined requirements is established. To cope with the inherent computational complexity, heuristics are developed to effectively narrow the problem space. Subsequently, this method's applicability and scalability are respectively evaluated qualitatively within an automotive case study and quantitatively by means of a tool performance analysis.
  • Publication
    Design of self-adaptation in distributed embedded systems
    (Verlag Dr. Hut, 2015)
    Weiß, Gereon
    ;
    Knorr, Rudi
    ;
    Bauer, Bernhard
    Nowadays, complex computers are integrated in numerous devices and are deployed in diverse application areas, for example in the automotive, avionic, health-care, and industrial automation domain. These embedded systems are evolving towards complex interconnected and adaptive systems. They increasingly integrate more and more functionality and must function under varying conditions and in diverse situations. Therefore, distributed embedded systems become self-adaptive so that they can adjust to varying context situations. This poses new challenges for the development of these self-adaptive distributed embedded systems. Therefore, this thesis introduces a novel model-driven approach for designing self-adaptation of these systems. The presented approach is applied to the application domain of automotive Electrics / Electronics (E/E).
  • Publication
    Reducing the verification effort for interfaces of automotive infotainment software
    ( 2015)
    Drabek, Christian
    ;
    Paulic, Annette
    ;
    Weiß, Gereon
    We present a novel approach and effective tooling to reduce the effort for the interface verification of in-vehicle software components. Our models create different views of the system. Layered reference models separate the description of the structure and the behavior of the services' communication. This simplifies the behavior descriptions and facilitates the usage of different communication technologies, e.g., D-Bus or CAN. Since the reference models are executable specifications, they can be used to verify the communication of the modeled services. This can be tested live or from a trace. In case of required changes to an interface, regression testing can be performed automatically using only the model. We evaluate the benefits and implications of our approach and tool with a case study of an in-vehicle audio function.
  • Publication
    Challenges of a safe adaptation architecture for vehicles
    ( 2014)
    Weiß, Gereon
    The promising advent of fully electric vehicles and automated driving also means a shift towards fully electrical control of the existing and new vehicle functions. In particular, critical X-by-wire functions require sophisticated redundancy solutions. As a result, the overall Electric/Electronic (E/E) architecture of a vehicle is becoming even more complex and costly. The talk introduces the challenges of future vehicle software architectures. In the course of the SafeAdapt project novel architecture concepts are developed which base on adaptation to address the needs of a new E/E architecture for FEVs regarding safety, reliability and cost-efficiency. This will reduce the complexity of the system and the interactions by generic, system-wide fault and adaptation handling. It also enables extended reliability despite failures, improvements of active safety, and optimized resources.
  • 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
    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
    Context modeling for dynamic configuration of automotive functions
    ( 2013)
    Weiß, Gereon
    ;
    Grigoleit, Florian
    ;
    Struss, Peter
    Current vehicles are usually equipped with an abundance of advanced driver assistant systems. Only a limited number of them can really be active permanently. This motivates our goal of providing the car with the means necessary to dynamically adapt the set of active functions to its current requirements. In this paper, we present a generic context modeling approach suitable for dynamic configuration of automotive functions. The demonstration of the feasibility of the proposed solution and evaluation of its effectiveness was based on a simulated prototypical system configuration. The simulations yielded to a significant reduction in average function activity of an exemplary car system. Depending on the provided context parameters, a reduction of up to 24% was achieved.
  • 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.