Dr. rer. nat.

Weiß, Gereon

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Now showing 1 - 7 of 7
  • Publication
    Approach for Argumenting Safety on Basis of an Operational Design Domain
    ( 2024)
    Weiß, Gereon
    ;
    Zeller, Marc
    ;
    Schoenhaar, Hannes
    ;
    Drabek, Christian
    ;
    Kreutz, Andreas
    The Operational Design Domain (ODD) is a representative model of the real world in which an Automated Driving System (ADS) is intended to operate. The definition of the ODD is a crucial part of the development process for such an artificial intelligence (AI)-enabled system. This is due to the fact that the ODD is the basis for several critical development activities, like defining system-level requirements, test & verification, and building a well-founded safety case for an AI-based ADS. Since an inadequately defined ODD poses a major safety concern for the entire development, an ODD must be defined completely and consistently during the development process. In this work, we present an approach for the ODD definition and maintenance during the development of safety-critical AI-based ADS functionalities and provide evidences to argue the sufficient completeness and consistency. We demonstrate the feasibility of our approach by an industrial use case of a fully automated system in the railway domain.
  • 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
    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
    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
    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.