Title
Extracting Environmental Constraints to Make Reactive System Specifications Realizable
Abstract
Many fatal accidents of safety critical reactive systems have occurred in unexpected situations which had not been considered during the design and test phases of the systems. To prevent these accidents, reactive systems should be designed to respond appropriately to any requests of any timing from environments. Verifying this property at specification phase reduces the development costs of safety critical reactive systems. This property of a specification is well known as realizability. If a specification was found not to be realizable, we have to determine the flaws in the unrealizable specification. Unrealizability of a specification arises from arbitrary requirements given by system designers. From a different view, it can be thought that the unrealizable specification implicitly imposes a precondition on the behavior of environment, although a system can not control the behavior of environment. If it is possible to obtain the precondition in intuitively comprehensive forms, it is easy for system designers to understand the cause of flaws in specifications. In this paper, we propose methods for deriving constraints on the behavior of environments, which is implicitly imposed by unrealizable specifications. Instead of realizability, we use strong satisfiability which is a necessary condition for realizability, due to the fact that many practical unrealizable specifications are also strongly unsatisfiable, and strong satisfiability have the advantage of lower complexity for analysis against realizability. These methods derive constraints in propositional linear temporal logic from B\"uchi automata representing specifications. The expressions of derived constraints are limited to simple and intuitively comprehensive forms where only two temporal operators appear successively. We also give proofs for three correctness properties of our methods, i.e. the termination property, the soundness property, and the weakest constraints derivability. Finally, we discuss applicability of our methods.
Year
DOI
Venue
2009
10.1109/APSEC.2009.70
APSEC
Keywords
Field
DocType
methods derive constraint,specification phase,strong satisfiability,unrealizable specification,soundness property,reactive system specifications realizable,environmental constraints,correctness property,intuitively comprehensive form,safety critical reactive system,practical unrealizable specification,system designer,software reliability,data mining,precondition,buechi automaton,temporal logic,satisfiability,automata,automata theory,system design,buchi automata,reactive system,control systems,specification,linear temporal logic
Computer science,Correctness,Satisfiability,Precondition,Theoretical computer science,Linear temporal logic,Soundness,Temporal logic,Reactive system,Realizability
Conference
ISSN
Citations 
PageRank 
1530-1362
7
0.55
References 
Authors
14
4
Name
Order
Citations
PageRank
Shigeki Hagihara17812.33
Yusuke Kitamura270.55
Masaya Shimakawa3417.54
Naoki Yonezaki410720.02