Abstract
Hybrid systems—more precisely, their mathematical models—can exhibit behaviors, like Zeno behaviors, that are absent in purely discrete or purely continuous systems. First, we observe that, in this context, the usual definition of reachability—namely, the reflexive and transitive closure of a transition relation—can be unsafe, i.e., it may compute a proper subset of the set of states reachable in finite time from a set of initial states. Therefore, we propose safe reachability, which always computes a superset of the set of reachable states. Second, in safety analysis of hybrid and continuous systems, it is important to ensure that a reachability analysis is also robust w.r.t. small perturbations to the set of initial states and to the system itself, since discrepancies between a system and its mathematical models are unavoidable. We show that, under certain conditions, the best Scott continuous approximation of an analysis A is also its best robust approximation. Finally, we exemplify the gap between the set of reachable states and the supersets computed by safe reachability and its best robust approximation.
Original language | English |
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Pages (from-to) | 75-99 |
Number of pages | 25 |
Journal | Theoretical Computer Science |
Volume | 747 |
Early online date | 10 Aug 2018 |
DOIs | |
Publication status | Published - 7 Nov 2018 |
Bibliographical note
Funding Information:Research partially supported by US NSF award #1736754 “A CPS Approach to Robot Design” the ELLIIT Swedish Strategic Area initiative, and the Swedish Knowledge Foundation project “AstaMoCA: Model-based Communications Architecture for the AstaZero Automotive Safety Facility”.
Publisher Copyright:
© 2018 The Authors
Keywords
- Domain theory
- Hybrid systems
- Reachability
- Robustness
ASJC Scopus subject areas
- Theoretical Computer Science
- General Computer Science