When modeling concurrent or cyber-physical systems, non-functional requirements such as time are important to consider. In order to improve the timing aspects of a model, it is necessary to have some notion of what it means for a process to be faster than another, which can guide the stepwise refinement of the model. To this end we study a faster-than relation for semi-Markov decision processes and compare it to standard notions for relating systems. We consider the compositional aspects of this relation, and show that the faster-than relation is not a precongruence with respect to parallel composition, hence giving rise to so-called parallel timing anomalies. We take the first steps toward understanding this problem by identifying decidable conditions sufficient to avoid parallel timing anomalies in the absence of non-determinism.
|Journal||Electronic Proceedings in Theoretical Computer Science, EPTCS|
|Number of pages||14|
|Publication status||Published - 20 Jan 2020|
|Event||16th Workshop on Quantitative Aspects of Programming Languages and Systems, QAPL 2019 - Prague, Czech Republic|
Duration: 7 Apr 2019 → …
|Conference||16th Workshop on Quantitative Aspects of Programming Languages and Systems, QAPL 2019|
|Period||07/04/2019 → …|
Bibliographical noteFunding Information:
Acknowledgements. Mathias R. Pedersen was supported by the ASAP project (no. 4181-00360) funded by the Danish Council for Independent Research. Kim G. Larsen was supported by the ERC Advanced Grant LASSO (no. 867096).
© M.R. Pedersen, G. Bacci, & K.G. Larsen.
Copyright 2020 Elsevier B.V., All rights reserved.