Analysing Sanity of Requirements for Avionics Systems (Preliminary Version)

TL;DR

This paper introduces new automated techniques for verifying the consistency, redundancy, and completeness of formalized requirements in avionics systems, enhancing requirement quality assurance.

Contribution

It presents novel methods for automatic sanity checking of requirements expressed in temporal logic, including consistency, redundancy, and completeness evaluations, with experimental validation and industrial case studies.

Findings

All inconsistencies and their sources can be identified.

The methods effectively detect redundant requirements.

Completeness evaluation suggests missing properties.

Abstract

In the last decade it became a common practice to formalise software requirements to improve the clarity of users' expectations. In this work we build on the fact that functional requirements can be expressed in temporal logic and we propose new sanity checking techniques that automatically detect flaws and suggest improvements of given requirements. Specifically, we describe and experimentally evaluate approaches to consistency and redundancy checking that identify all inconsistencies and pinpoint their exact source (the smallest inconsistent set). We further report on the experience obtained from employing the consistency and redundancy checking in an industrial environment. To complete the sanity checking we also describe a semi-automatic completeness evaluation that can assess the coverage of user requirements and suggest missing properties the user might have wanted to formulate. The usefulness of our completeness evaluation is demonstrated in a case study of an aeroplane control system.