Robustness in timed automata : analysis, synthesis, implementation

Abstract : Timed automata are a formalism to model, verify, and synthesize real-time systems. They have the advantage of having an abstract mathematical semantics, which allow formalizing and solving several verification and synthesis problems. However, timed automata are intended to design models, rather than completely describe real systems. Therefore, once the design phase is over, it remains to check whether the behavior of an actual implementation corresponds to that of the timed automaton model. An important step before implementing a system design is ensuring its robustness. This thesis considers a notion of robustness that asks whether the behavior of a given timed automaton is preserved, or can be made so, when it is subject to small perturbations. Several approaches are considered: Robustness analysis seeks to decide whether a given timed automaton tolerates perturbations, and in that case to compute the (maximum) amount of tolerated perturbations. In robust synthesis, a given system needs to be controlled by a law (or strategy) which tolerates perturbations upto some computable amount. In robust implementation, one seeks to automatically transform a given timed automaton model so that it tolerates perturbations by construction. Several perturbation models are considered, ranging from introducing error in time measures (guard enlargement), forbidding behaviors that are too close to boundaries (guard shrinking), and restricting the time domain to a discrete sampling. We also formalize robust synthesis problems as games, where the control law plays against the environment which can systematically perturb the chosen moves, by some bounded amount. These problems are studied on timed automata and their variants, namely, timed games, and weighted timed automata and games. Algorithms for the parameterized robustness analysis against guard enlargements, and guard shrinkings are presented. The robust synthesis problem is studied for two variants of the game semantics, for timed automata, games, and their weighted extensions. A software tool for robustness analysis against guard shrinkings is presented, and experimental results are discussed. The robust implementation problem is also studied in two different settings. In all algorithms, an upper bound on perturbations that the given timed automaton tolerates can be computed.
Document type :
Theses
Complete list of metadatas

Cited literature [101 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00910333
Contributor : Abes Star <>
Submitted on : Wednesday, November 27, 2013 - 6:24:30 PM
Last modification on : Thursday, January 11, 2018 - 6:20:13 AM
Long-term archiving on : Friday, February 28, 2014 - 11:05:57 AM

File

Sankur2013.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-00910333, version 1

Collections

Citation

Ocan Sankur. Robustness in timed automata : analysis, synthesis, implementation. Other [cs.OH]. École normale supérieure de Cachan - ENS Cachan, 2013. English. ⟨NNT : 2013DENS0016⟩. ⟨tel-00910333⟩

Share

Metrics

Record views

502

Files downloads

305