David W. J. Stringer-Calvert

Formal verification of functional properties of a SCR-style software requirements specification using PVS

Industrial software companies developing safety-critical systems are required to use rigorous safety analysis techniques to demonstrate compliance to regulatory bodies. In this paper, we describe an approach to formal verification of functional properties of requirements for an embedded real-time software written in software cost reduction (SCR)-style language using PVS specification and verification system. Key contributions of the paper include development of an automated method of translating SCR-style requirements into PVS input language as well as identification of property templates often needed in verification. Using specification for a nuclear power plant system, currently in operation, we demonstrate how safety demonstration on requirements can be accomplished while taking advantage of assurance provided by formal methods.

PVS: An Experience Report

PVS is a comprehensive interactive tool for specification and verification combining cui expressive specification language with an integrated suite of tools for theorem proving and model checking. PVS has many academic and industrial users and has been applied to a wide range of verification tjisks. In this note, we summarize some of its applications.

Formal Verification of Functional Properties of an SCR-Style Software Requirements Specification Using PVS

Industrial software companies developing safety-critical systems are required to use rigorous safety analysis techniques to demonstrate compliance to regulatory bodies. While analysis techniques based on manual inspection have been successfully applied to many industrial applications, we demonstrate that inspection has limitations in locating complex errors in software requirements.In this paper, we describe the formal verification of a shutdown system for a nuclear power plant that is currently operational in Korea. The shutdown system is an embedded real-time safety-critical software, and has a description in a Software Cost Reduction (SCR) style specification language. The key component of the work described here is an automatic method for translating SCR-style Software Requirements Specifications (SRS) into the language of the PVS specification and verification system. A further component is the use of property templates to translate natural language Program Functional Specifications (PFS) into PVS, allowing for high-assurance consistency checking between the translated SRS and PFS, thereby verifying the required functional properties.