EASE for Windows

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A knowledge-based system for assessing workplace exposure to potentially hazardous new substances.

Client:

The Health and Safety Executive

Problem:

EU regulations require a manufacturer of a new substance to notify the appropriate authority, who will carry out a risk assessment of it. To aid this process, guidance is provided by the regulator for use by both authorities and manufacturers. This is usually provided as a paper document. HSE decided that a computer based guidance system would be of benefit. The area addressed is that of exposure to a substance in the workplace.

Exposure assessment is an expert task, requiring an experienced occupational chemist, as many of the chemical and physical properties of a new substance are not known to the assessor a priori.

For the system to be deployed, it must incorporate best practice knowledge engineering techniques and, as there are safety-related considerations and AIAI and the HSE are committed to quality, the work had to be carried out in accordance with ISO9001 standards.

Approach:

AIAI and HSE staff worked together using the CommonKADS knowledge engineering methodology to model the task and capture the knowledge involved. Execution of the work was audited against TickIT criteria by Lloyds Register.

Main Features:

The use of CommonKADS ensured that the problem requirements and the expert knowledge involved were captured within a standard framework which promoted unambiguous communication between the members of the project team and provided a solid base for system design, implementation, maintenance, and enhancements.

The system guides the user by offering a menu of appropriate choices whenever it needs information. When numerical values must be provided, e.g. vapour pressure, sanity checks are carried out.

The user can always back-track and change the answer to an earlier question.

A full explanation of the conclusion is always given, and an explanation of why a particular question is being asked is always available. Each guidance session is logged.

Implementation:

The system was implemented using the NASA CLIPS development tool for the inference engine and knowledge base. Originally developed under Unix, the system was readily delivered under Windows through the use of AIAI's multiplatform wxCLIPS tool for the user interface.

The Knowledge-based approach allowed the system to be implemented as three separate modules: inference engine, knowledge base, and user interface. Initially required to run under MS-DOS on a PC AT equivalent with 640K of RAM, a second release to run under Windows 3.1 reused the inference engine and knowledge base, requiring only a revised user interface. Enhancements made to the inference engine and the knowledge base were immediately available to both environments.

The system has been widely distributed for use by authorities throughout Europe.

For more information:
contact r.rae@ed.ac.uk

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