Departmental Papers (CIS)

Document Type

Conference Paper

Subject Area

CPS Real-Time, CPS Formal Methods

Date of this Version

2006

Publication Title

Lecture Notes in Computer Science: Hybrid Systems: Computation and Control

Volume

3927

First Page

19

Last Page

33

DOI

10.1007/11730637_5

Comments

From the 9th International Workshop, HSCC 2006, Santa Barbara, CA, USA, March 29-31, 2006.

Abstract

Model checking is a popular algorithmic verification technique for checking temporal requirements of mathematical models of systems. In this paper, we consider the problem of verifying bounded reachability properties of stochastic real-time systems modeled as generalized semi-Markov processes (GSMP). While GSMPs is a rich model for stochastic systems widely used in performance evaluation, existing model checking algorithms are applicable only to subclasses such as discrete-time or continuous-time Markov chains. The main contribution of the paper is an algorithm to compute the probability that a given GSMP satisfies a property of the form “can the system reach a target before time T within k discrete events, while staying within a set of safe states”. For this, we show that the probability density function for the remaining firing times of different events in a GSMP after k discrete events can be effectively partitioned into finitely many regions and represented by exponentials and polynomials. We report on illustrative examples and their analysis using our techniques.

Permission Statement

The original publication is available at www.springerlink.com

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Date Posted: 25 June 2012