Resilient and Secure Activity Control for Flexible Time-Triggered Systems

• Applicant: Professor Dr.-Ing. Gerhard Fohler
• Subject Area: Security and Dependability, Operating-, Communication- and Distributed Systems
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 490872987

The Time Triggered (TT) paradigm of activations has been shown to be very well suited for closed safety-critical embedded systems with apriori known configurations and strict timing constraints, as in the avionics, railway, automotive or space domain. Its success has been documented both scientifically and in industrial applications, notably by the company TTTech, selling TTP and TTA technologies, which are both among the candidates for the on-board communication systems of the lunar gateway. This successful commercial adoption is based on two main points:(1) the application of the TT paradigm with a focus on simplicity and efficiency, providing a package of f features such as strong real-time guarantees, reliability, and safety; and(2) a variety of algorithms provides further guarantees (e.g., membership, transparent redundancy, rapid mode change, etc.) on top of the provided globally consistent, sparse time base TT systems establish.Unfortunately, as hardware platforms become more powerful and communication links more versatile, executing applications and transmitting traffic with different characteristics and criticalities, not all known beforehand or changing over time, the strictness, limited flexibility and resource overprovisioning of TT systems, prohibits their efficient application and reduces their scope to niches.A number of methods have been introduced to include some flexibility in TT systems, typically by relaxing indiviual strict TT properties while sacrificing some of the gurantees the TT paradigm conveys. For example, it has been proposed to relax task to slot assignments, slot boundaries, or even to give up on time synchronization (though under the assumption of drift- and jitter-limited clocks). However, in these proposals, the untying of any of these elements has lead to loosing the entire bundle of properties and guarantees TT achieves, not only for the application that motivated this relaxation, but for all co-existing applications.In this project, we take a more principled approach by sacrificing time in favor of a generalized, but reliable activation to systematically investigate the relation between activation properties assumed and guarantees obtained. Our ultimate goal, to which this project contributes, is to obtain without time and the strictness of TT operation, what time-triggered systems achieve for the highly safety critical application fragment,while smoothly integrating other application characteristics, efficiently and on the basis of a solid understanding of the time- dependence of the guarantees they require. We will provide for various bundles to be configured, meeting various demands and criticalities of applications and systems, not meaning toreplace existing TT solutions, but to provide a wider range of solutions and tradeoffs to be selected and simultaneously deployed in today's and future cyber-physical and dependent systems.

• DFG Programme: Research Grants
• International Connection: Luxembourg
• Cooperation Partner: Professor Dr.-Ing. Marcus Völp