Dr. rer. nat.

Weiß, Gereon

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Now showing 1 - 10 of 11
  • 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
    Verifying network performance of cyber-physical systems with multiple runtime configurations
    ( 2015)
    Manderscheid, Martin
    ;
    Weiß, Gereon
    ;
    Knorr, Rudi
    Modern Cyber-Physical Systems (CPS) must increasingly adapt to changing contexts, like smart cars to changing driving conditions. Thus, design approaches are facing a rapidly growing number of network runtime configurations. With recent approaches this problem can be solved for design space exploration (DSE) by analyzing the network performance of single configurations which are intended to represent the entire runtime variability space. This technique can be applied for DSE since the latter only intends to find an optimized system setup. Yet it does not meet the requirements of network verification, since it does not necessarily find the worst-case for all applications. To solve this, we developed an integrated model, which allows describing runtime variability in the network performance model with a0-1 linear-fractional program. Thus, we can cover entire runtime variability spaces without analyzing every single network runtime configuration. Although the approach utilizes heuristics, it still guarantees worst-case results. We can show that in comparison to state-of-the-art methods our approach scales for large automotive systems with multiple network configurations. Moreover, our evaluation results highlight the superior capabilities of our method with respect to accuracy and computation time.
  • Publication
    Parameterization of fail-operational architectural patterns
    ( 2015)
    Oliveira da Penha, Dulcineia
    ;
    Weiß, Gereon
    In today's cyber physical systems, adaptability concepts can be used to fulfill fail-operational requirements while enabling optimized resource utilization. However, the applicability of such concepts highly depends on the support for the engineering during system development. We propose an approach to cope with the challenges of fail-operational behavior of CPS in which engineers are supported by design concepts for realizing safety, reliability, and adaptability requirements through the use of architectural patterns. The approach allows expressing concepts for fail-operational behavior at the software architecture level. By our approach, the effort for developing adaptive CPS can be kept low by utilizing fail-operational architectural patterns for general and reoccurring safety-relevant mechanisms. This is demonstrated by an application to an automotive case system.
  • Publication
    Pattern-based approach for designing fail-operational safety-critical embedded systems
    ( 2015)
    Penha, Dulcineia
    ;
    Weiß, Gereon
    ;
    Stante, Alexander
    To deal with fail-operational (FO) requirements intoday's safety-critical networked embedded systems (SCNES), engineers have to resort to concepts such as redundancy, monitoring, and special shutdown procedures. Hardware-based redundancy approaches are not applicable to many embedded systems domains (e.g., automotive systems), because of prohibitive costs. In this scenario, adaptability concepts can be used to fulfill these FO requirements while enabling optimized resource utilization. However, the applicability of such concepts highly depends on the support for the engineering during system development. We propose an approach to cope with the challenges of fail-operational behavior of SCNES in which engineers are supported by design concepts for realizing safety, reliability, and adaptability requirements through the use of architectural patterns. The approach allows expressing FO concepts at the software architecture level. This lowers the effort for developing SCNES by utilizing generic patterns for genera land reoccurring mechanisms.
  • 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
    Parameterization of fail-operational architectural patterns
    ( 2015)
    Oliveira da Penha, Dulcineia
    ;
    Weiß, Gereon
    In today's cyber physical systems, adaptability concepts can be used to fulfill fail-operational requirements while enabling optimized resource utilization. However, the applicability of such concepts highly depends on the support for the engineering during system development. We propose an approach to cope with the challenges of fail-operational behavior of CPS in which engineers are supported by design concepts for realizing safety, reliability, and adaptability requirements through the use of architectural patterns. The approach allows expressing concepts for fail-operational behavior at the software architecture level. By our approach, the effort for developing adaptive CPS can be kept low by utilizing fail-operational architectural patterns for general and reoccurring safety-relevant mechanisms. This is demonstrated by an application to an automotive case system.
  • Publication
    SafeAdapt. Safe Adaptive Software for Fully Electric Vehicles
    ( 2015)
    Weiß, Gereon
    ;
    Eilers, Dirk
    Presentation of the European funded SafeAdapt project.
  • Publication
    Memory concepts for enabling adaptivity in distributed embedded systems
    ( 2014)
    Schleiß, Philipp
    ;
    Zeller, Marc
    ;
    Weiß, Gereon
    Establishing cost and resource efficient dependability through means of adaptivity in safety-critical distributed embedded systems is a strenuous endeavour, as the varying requirements on resilience, control and efficiency across domains prohibits a single solution to suit all needs. To assist the process of determining a safe and efficient system architecture with satisfactory precision, this work exemplifies the importance of differentiation by only addressing distributed embedded systems that perform multiple functions with alternating levels of criticality. Further, they do not require full fail-operational behaviour, thus allowing to sacrifice less important functions in the pursuit of preserving safety. Herein, a dynamic instantiation and graceful degradation strategy is developed to subsequently study its effect on cost when implemented in conjunction with execute-in-place (NOR-flash) or block-addressable (NAND-flash) memory concepts. Even though NOR-flash is generally considered to be a better candidate for such systems, this qualitative research produces evidence that NAND-flash memory concepts are likely to financially outperform traditional architectures when considering adaptivity.
  • 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
    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.