Design of fault-tolerant virtual execution environments for cyber-physical systems

Abstract

The last decade revealed the vast economical and societal potential of Cyber-Physical Systems (CPS) which integrate computation with physical processes. In order to better exploit this potential, designers of CPS are trying to take advantage of novel technological opportunities provided by the unprecedented efficiency of today's hardware. There are, however, considerable challenges to this endeavor.

First, there is a strong trend towards softwarization. Functions that were originally implemented in hardware are now being increasingly realized in software. This fact, together with the ever growing functionality of modern CPS, translates to unrestrained code generation which, in turn, directly influences their safety and security. Second, the spreading adaptation of multi-core and manycore architectures, due to their considerable increase in computation power, additionally generates issues related to timing properties, resource partitioning, task mapping and scalability.

In order to overcome these challenges, this thesis investigates the idea of adopting virtualization technology to the domain of CPS. Several research questions originate from this idea and the following work aims at answering those questions. It addresses both technological and methodological issues. With respect to the technological aspects, it investigates problems and proposes solutions related to timing properties of a virtualized execution platform as well as the thereon based high availability technique. Regarding the methodological aspects, it discusses models and methods for the planing of safe and efficient virtualized CPS compute and control clusters, proposes architectures for the development and verification of virtualized CPS applications as well as for the testing of non-functional characteristics of the underlying software and hardware infrastructure. Further, through a set of experiments, this thesis thoroughly evaluates the proposed solutions.

Finally, based upon the provided results and some new considerations regarding the requirements of future CPS applications, it gives an outlook towards a generic virtualized execution platform architecture for emerging CPS.