Courtesy Robin Drogemuller: In the various engineering disciplines, communication between the members of the team is critical. For communication to occur we need :

• shared knowledge
• a context for the message
• a message itself
• a language in which to encode the message
• a medium for exchanging the body of the message.

The STEP standards (ISO 10303) specify a set of protocols to exchange product model data for international trade and cooperation in major industries including automotive, electronics, aerospace, plant engineering and civil engineering.

The STEP standards are defined using a product modelling language called EXPRESS (ISO10303:11). The major portion of the STEP standards is made up of Application Protocols. These define the domain of discourse (shared knowledge) in an exchange. The context of the exchange is provided by the project.The message is exchanged using file-based exchange based on IS010303:21. The language for exchange of the schema is EXPRESS, the Part 21 exchange format is used to encode the message. The medium is the exchange file.

In this example, MINERVA is used to process STEP/Express schema files in a standard Internet Browser on the client machine for efficient local processing. The necessary programs, schema, and product data model are obtained from the server using the Internet.

The example is provided by Robin Drogemuller of CSIRO based on work done while he was with James Cook University.

The schema "schema.pro" is implemented in ISO/IEC 13211-1 Prolog.

The product model "tetra.exg" is given according to ISO-10303:21 STEP/"Clear text encoding of an exchange file".