The work reported in the present paper concerns the development of a computer system which can acquire an attribute grammar knowledge base from a technical text. The use of attribute grammars is explored both in the implementation of the system and in the target-knowledge representation of the text content. Knowledge-based encoding of the text knowledge content is accomplished and inferential exploitation of the resulting knowledge base is possible using the same attribute grammar interpreter as our knowledge engineering tool. The specific problems involved in using attribute grammars for representing both the knowledge content of a text and the knowledge required for extracting and formalising that content are studied, and some solutions are proposed. The techniques proposed can be applied to technical texts that deliver knowledge about the structure of objects and the functional relations of their parts. The prerequisite knowledge problem for text analysis is addressed and faced using attribute grammars. The kinds of prerequisite knowledge considered include subject-related background knowledge, linguistic knowledge and representation knowledge.

The use of attribute grammars for knowledge representation is examined in the present paper. It is shown how data knowledge and knowledge-base knowledge can be represented using syntactic and semantic notation. Control knowledge is represented by the parsing mechanism of the interpreter used. It is proposed that attribute grammar evaluators may prove to be useful knowledge engineering tools.

A syntax-directed interpreter of attribute grammars is applied to interpret meta grammars describing translators. A specific example is used which concerns the formal description of the same syntax-directed interpreter of attribute grammars for illustration of our approach.

The design and the performance of a fast iterative analog computer that is based on the use of pulse-ratio modulation representation is presented. The basic element employed in the design of the computing units of the computer is a pulse-ratio modulator. The solution of an eigenvalue problem by the computer is presented as an example of its applications. The results obtained agree well with analytical calculations.

A computer control system simulation method utilizing two computers is presented. One is a control computer operating under almost actual conditions. The other is a multiprogrammed computer that simulates the plant. The time taken by the control computer to compute the control variables can be a function of the plant state. An optimum control example illustrating the application of the method is given.