Dr.-Ing.

Kuhn, Thomas

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  • Publication
    Towards a Virtual Continuous Integration Platform for Advanced Driving Assistance Systems
    ( 2019)
    Bachorek, Adam
    ;
    Schulte-Langforth, Felix
    ;
    Witton, Alexander
    ;
    Kuhn, Thomas
    ;
    Antonino, Pablo Oliveira
    Recent technological progress in computational engineering and systems design will enable the vision of autonomous driving coming true anytime soon. Functional but particularly also qualitative aspects of automotive functions are therefore gaining in importance more than ever before. This is due to the growing complexity of modern vehicles that gradually evolve into cyber-physical systems giving rise to the increasingly ambitious challenge of reliably validating the non-/functional integration of all their inherent subsystems. Thus, whereas traditional approaches to component and system testing are becoming more and more inappropriate for costs and general viability reasons, simulation-based methodologies offer an adequate solution due to their commonly scalable and generic nature. However, this is only true given a sufficiently high fidelity of the applied simulation models and a straightforward-in-use yet powerful-in-service evaluation platform with flexible support for execution semantics nesting, co-simulator coupling, and interfacing downstream tools with monitoring and visualization capabilities. In this regard, we introduce our concept of a continuous integration platform allowing for virtually prototyping technical systems of any kind that is applicable at any stage of the development process thanks to arbitrary levels of abstraction and wide-range tooling compatibility. This platform is based on the approved FERAL simulation framework at its core combined with versatile architectural components that are adaptable for domain-specific and cross-domain use cases. We focus this work on Advanced Driving Assistance Systems (ADAS) functions and showcase the end-user operation of the instantiated platform from the configuration of traffic scenarios over adjusting the functional logic and parameter values up to the visual validation of simulation results.
  • Publication
    Supervised testing of concurrent software in embedded systems
    ( 2017)
    Jahic, Jasmin
    ;
    Kuhn, Thomas
    ;
    Jung, Matthias
    ;
    Wehn, Norbert
    The migration of sequential embedded software to multicore processors is a challenging task. Parallelization of software introduces concurrency bugs (e.g. data races), which only conditionally appear during testing because they strongly depend on the timing of the execution. Therefore, traditional testing approaches cannot efficiently test concurrent software. More appropriate are analysis approaches that prove the absence of software faults. Current approaches often produce false positives as they fail to consider all relevant synchronization sources. In this paper, we complement current analysis techniques by considering a scheduling scheme as a synchronization mechanism. We narrow the analysis by analyzing only relevant variants in execution timing that might produce concurrency bugs. Therefore, we eliminate a family of false positives caused by ignoring the scheduling synchronization. Engineers can optimize this scheduling scheme to satisfy different requirements. Our approach uses virtual prototyping to enable design space exploration of systems with complex scheduling schemes by investigating the influence of the scheduling scheme on the synchronization of concurrent software.
  • Publication
    Accelerated simulated fault injection testing
    ( 2017)
    Cioroaica, Emilia
    ;
    Jahic, Jasmin
    ;
    Kuhn, Thomas
    ;
    Peper, Christian
    ;
    Uecker, Denis
    ;
    Dropmann, Christoph
    ;
    Munk, Peter
    ;
    Rakshith, Amarnath
    ;
    Thaden, Eike
    Fault injection testing approaches assess the reliability of execution environments for critical software. They support the early testing of safety concepts that mitigate the impact of hardware failures on software behavior. The growing use of platform software for embedded systems raises the need to verify safety concepts that execute on top of operating systems and middleware platforms. Current fault injection techniques consider the resulting software stack as one black box and attempt to test the reaction of all components in the context of faults. This leads to very high software complexity and consequently requires a very high number of fault injection experiments. Testing the software components, such as control functions, operating systems, and middleware, individually would lead to a significant reduction of the number of experiments required. In this paper, we illustrate our novel approach for fault injection testing, which considers the components of a software stack, enables re-use of previously collected evidences, allows focusing testing on highly critical parts of the control software, and significantly lowers the number of experiments required.
  • Publication
    Virtual validation of cyber physical systems
    ( 2015)
    Feth, Patrik
    ;
    Bauer, Thomas
    ;
    Kuhn, Thomas
    The increasing importance of Cyber Physical Systems (CPS) yields new challenges for their systematic and efficient quality assurance. CPS are characterized by open and heterogeneous architectures and environments. For embedded systems, this implies a separation of the currently very tight integration of hardware and software components. Development and testing of these systems require new development environments that enable prototyping and testing of system concepts on different levels of abstraction. In this paper, we describe the extension of our FERAL framework to support the prototyping of automotive CPS by adding an AUTOSAR simulation environment. This supports the virtual development of next generation open architectures that integrate software components from multiple suppliers on one hardware platform.
  • Publication
    Virtual prototyping of distributed embedded systems with FERAL
    ( 2014)
    Braun, Tobias
    ;
    Christmann, Dennis
    ;
    Gotzhein, Reinhard
    ;
    Igel, Anuschka
    ;
    Kuhn, Thomas
    Distributed embedded systems are found in time- and safety-critical domains, such as avionics and automotive. Virtual prototyping is a suitable approach for the development of such systems, since it enables early testing and early evaluation of design decisions in realistic simulated environments. Existing simulators only focus on specific aspects and application domains. However, an accurate prediction of the overall system behaviour of complex distributed embedded systems requires the consideration of multiple aspects together, e.g., communication and functional behaviour. Therefore, a mechanism for the rapid coupling of simulators is required to create holistic simulation environments. In this paper, we survey our modular simulator framework FERAL, which provides a generic solution to virtual prototyping by enabling the rapid coupling and exchange of diverse simulators, even with heterogeneous simulation models. Thus, simulators operating on different abstraction levels can be applied together. We demonstrate the adaptation of FERAL by incorporating several simulators, in particular, existing simulators (Simulink, ns-3), and our newly developed simulators for the automotive communication technologies CAN and FlexRay. We then demonstrate FERAL's capabilities by evaluating different design alternatives for an adaptive cruise control system in a real world scenario.
  • Publication
    FERAL - Framework for Simulator Coupling on Requirements and Architecture Level
    ( 2013)
    Kuhn, Thomas
    ;
    Forster, Thomas
    ;
    Braun, Tobias
    ;
    Gotzhein, Reinhard
    Simulation technologies are imperative for embedded systems development. They enable the evaluation of decisions already early in development processes. Simulators are focused on a subset of effects that affect the operation of embedded systems. Accurate prediction of embedded system behavior on system level, however, requires the consideration of multiple effects, e.g. communication behavior, system environments, and functional behavior of all relevant system components. This requires the coupling of specialized simulators to create holistic simulation scenarios. In this paper, we present FERAL, our framework for simulator coupling, which enables the integration of simulators with heterogeneous simulation models. We describe the overall coupling approach of FERAL, its simulation model, and its approach for the horizontal and vertical integration of simulation models. We show the applicability of FERAL by a realistic example that demonstrates the potential of simulator coupling for early fault detection.