WP2

Requirements Capture

Objective:
Work Package 2 is to investigate methods for establishing the requirements for the refurbishment of control systems that are important to safety, and to develop an associated engineering process that adequately supports the definition of these requirements.

The requirements capture process is a difficult but vital part of the project. The 'requirements' to be captured are safety, application and system requirements.

Existing requirements are recovered using techniques incorporating formal and computer-aided techniques to capture requirements from existing design documentation. e.g. the analysis of ladder logic diagrams for discrete relay-based systems that may need to be replaced by computer based equivalents.

Further requirements are established through using the following methods:

Stakeholder point of view
Environment change analysis
Other methods found during research

An information collection exercise has been carried out using the following sources:

Nuclear industry re: related projects
Literature review: looking at forthcoming conferencses, review past publications of relevant journals.
University departments; centre for software reliability
Suppliers for opinions and product detail
Internet search
Previous experience of the participants' companies
Previous research experience including the REAIMS project

The framework for Work Package 2 has been identified, with three main components:

A requirements engineering lifecycle	First developed in the context of a safety lifecycle and Plant Modification Proposal (PMP).
A set of stakeholders or viewpoints	i.e. anyone whose work will be affected by the project.
A taxonomy of projects	Based on criticality, timeliness, size of code, cost, etc.