Adaptierung des Zeitverhaltens nicht-echtzeitfähiger Software für den Einsatz in zeitheterogenen Netzwerken

  • Adapting the timing behavior of non-real-time-capable software for deployment time-heterogeneous networks

Schommer, John; Kowalewski, Stefan (Thesis advisor); Rumpe, Bernhard (Thesis advisor)

1st ed.. - Aachen (2019, 2020)
Book, Dissertation / PhD Thesis

In: Aachener Informatik-Berichte 2020-03
Page(s)/Article-Nr.: 1 Online-Ressource (xv, 177 Seiten) : Illustrationen, DiagrammeReport number: AIB-2020-03

Dissertation, RWTH Aachen University, 2019

Abstract

Embedded systems are becoming increasingly connected in time-heterogeneous networks. Communicating with non-real-time systems without changing or deleting the often time-critical requirements. New is here the mix up of real-time and non-real-time requirements within one network. The time-critical requirements are then propagated across the network to other nodes. That is, passed while communication is done at runtime between real-time and non-real-time systems. However, if non-real-time systems do not meet the propagated requirements, the connected real-time systems can no longer guarantee that their specific main function is correctly executed. A methodology is needed that enables a structured evaluation and adaptation of non-real-time systems, in the case that the main function of the real-time systems is not jeopardized. The presented work deals with the software of such network nodes, which time-critical requirements are propagated on the one hand; where on the other hand, the requirements were not taken into account in the original design of the systems. Methods for the evaluation and adaptation of the software of these systems are presented, which aim to increase the fulfilment of the corresponding network nodes with the propagated time-critical requirements. These methods can also be used iteratively in agile development processes in an automated way, which are also being established today in the development of embedded systems. The evaluation is carried out on existing software or software freshly implemented. The multistep approach to this involves conformance-based validation of signals and path coverage with metrics based on software lifecycles. The subsequent adaptation should take into account the evaluation results and is supported via five design patterns on software in this thesis. Three of these design patterns have been developed mainly for node-to-node communication, the other two design patterns for use within network nodes. The evaluation and adaptation of the software can be carried out repeatedly. If the software under adaptation achieves a certain quality, for example a signal conformity to a certain reference signal, corresponding network nodes can be installed with real-time systems or on real-time platforms after completion of the adaptation in such a way that the specific main function of the connected real-time systems is executed correctly in time-critical terms. Also, use cases and time-sensitive requirements are catalogued in aspects of scheduling, memory management, and software platform timers. The thesis shows how test cases can be generated as the basis of an evaluation from these catalogues, and also provides metrics to assess the runtime results of the software. Case studies and collaborative projects with industry have examined the developed methods and software prototypes to demonstrate the applicability of them within established development processes.

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