A non-standard semantics for generating reduced transition systems (original) (raw)

Reduced Models for Efficient CCS Verification

Formal Methods in System Design, 2005

Verification of a concurrent system can be accomplished by model checking the properties on a structure representing the system; this structure is, in general, a transition system which contains a prohibitive number of states. In this paper, we apply a method to reduce the state explosion problem by pointing out the events of the system to be ignored on the basis of the property to be verified. We evaluate the method by means of a real application used as a case study: the system is specified by a CCS program, then the program is reduced by means of syntactic rules; afterwards, the corresponding transition system is built by means of a non-standard operational semantics, which performs further reductions during the construction. Prototype tools perform both kinds of reductions; finally the required properties are checked by means of the model checkers of the CWB-NC.

On the complexity of verifying concurrent transition systems

2002

In implementation verification, we check that an implementation is correct with respect to a specification by checking whether the behaviors of a transition system that models the program's implementation correlate with the behaviors of a transition system that models its specification. In this paper, we investigate the effect of concurrency on the complexity of implementation verification. We consider trace-based and tree-based approaches to the verification of concurrent transition systems, with and without fairness.

Formula Based Abstractions of Transition Systems for Real-Time Model Checking

Lecture Notes in Computer Science

When verifying concurrent systems described by transition systems, state explosion is one of the most serious problems. If quantitative temporal information (expressed by clock ticks) are considered, state explosion is even more serious. In this paper we present a non-standard (abstract) semantics for the ASTP language able to produce reduced transition systems. The important point is that the abstract semantics produces transition systems equivalent to the standard ones for what concerns the satisfiability of a given set of formulae of a temporal logic with quantitative modal operators. The equivalence of transition systems with respect to formulae is expressed by means of ρ, n-equivalence: two ρ, n-equivalent transition systems give the same truth value to all formulae such that the actions occurring in the modal operators are contained in ρ, and with time constraints whose values are less than or equal to n.

A tool for modeling, manipulation and analysis of concurrent systems based on CCS process language and LTS as its semantic model (Technical Report)

This paper is a technical report of an effort to build a tool for automatic specification and analysis of concurrent systems. The tool we present here has implemented the CCS process language and can build LTSs (Labelled Transition Systems) from CCS expressions. Furthermore, it can be used to reduce the state space of an LTS and to check whether two LTSs exhibit the same behaviour, using strong and weak bisimulation equivalence. It can parse Henessy-Milner logic formulas as well and also implements the U w and U s operators that enable recursive definitions. The tool is very simple, but it has the functionality needed to perform modeling, specification and verification. We give an illustration of that process for two classical examples in the concurrency theory: the Alternating Bit Protocol and Peterson's mutual exclusion algorithm.

Compositional Model Checking of Concurrent Systems

IEEE Transactions on Computers, 2014

This paper presents a compositional framework to address the state explosion problem in model checking of concurrent systems. This framework takes as input a system model described as a network of communicating components in a high-level description language, finds the local state transition models for each individual component where local properties can be verified, and then iteratively reduces and composes the component state transition models to form a reduced global model for the entire system where global safety properties can be verified. The state space reductions used in this framework result in a reduced model that contains the exact same set of observably equivalent executions as in the original model, therefore, no false counterexamples result from the verification of the reduced model. This approach allows designs that cannot be handled monolithically or with partial-order reduction to be verified without difficulty. The experimental results show significant scaleup of this compositional verification framework on a number of non-trivial concurrent system models.

Formal Verification of Concurrent Systems via Directed Model Checking Abstract

2006

Model checking suffers from the state explosion problem, due to the exponential increase in the size of a finite state model as the number of system components grows. Directed model checking aims at reducing this problem through heuristic-based search strategies. The model of the system is built while checking the formula and this construction is guided by some heuristic function. In this line, we have defined a structure-based heuristic function operating on processes described in the Calculus of Communicating Systems (CCS), which accounts for the structure of the formula to be verified, expressed in the selective Hennessy-Milner logic. We have implemented a tool to evaluate the method and verified a sample of well known CCS processes with respect to some formulae, the results of which are reported and commented.

Formal Verification of Concurrent Systems via Directed Model Checking

Electronic Notes in Theoretical Computer Science, 2007

Verification of temporal properties in concurrent systems

2003

Rapid growth of distributed systems stimulates many attempts to describe precisely the behavior of concurrent systems. The target of the research is to model complex systems, to automatically generate an executable code from abstract models, and to check the correctness of concurrent systems. In this thesis, a new concept of concurrent system verification is presented. The idea is based on building a new version of CTL temporal logic (QsCTL) over reachability graphs of systems defined by concurrent automata CSM. The proposed method is addressed to verify control-dominated systems. Many questions on concurrent system behavior may be asked easier in QsCTL than in traditional CTL. An original algorithm CBS (Checking By Spheres) for automatic evaluation of temporal formulas in this logic is presented. Another algorithm of state space reduction is designed. The presented ideas are implemented in TempoRG program, the element of the COSMA environment developed in ICS, WUT. The purpose of COSMA is to integrate formal verification methodology with concurrent systems design environment. The formulated theoretical concepts are illustrated with several examples concerning verification processes including quite complex industrial system.

Verification of Temporal Properties of Concurrent Systems

DAIMI Report Series, 1993

This thesis is concerned with the verification of concurrent systems modelled by process algebras. It provides methods and techniques for reasoning about temporal properties as described by assertions from an expressive modal logic -- the modal µ-calculus. It describes a compositional approach to model checking, efficient local and global algorithms for model checking finite-state systems, a general local fixed-point finding algorithm, a proof system for model checking infinite-state systems, a categorical completeness result for an intuitionistic version of the modal µ-calculus, and finally it shows some novel applications of the logic for expressing behavioural relations.

A non-standard semantics for generating reduced transition systems (original) (raw)

Related papers