The authors examine a particular type of domain-based metadata for which a complete ready-made conceptual framework is not and probably cannot be directly supported in predefined data models of knowledge-based representation paradigms. The data or knowledge base designer thus has the burden of sometimes working outside a familiar and otherwise appropriate model. The authors discuss issues arising in formulating certain domain-based metadata extensions and provide guidelines for developing them. These results derive from a continuing effort to create a knowledge base to support research on biological organisms. The added semantics are used to support a more flexible and reliable system for identification.>

A new method for computing minimal covers is presented using a new type of closure that allows significant reductions in the number of closures computed for normalizing relations. Benchmarks are reported comparing the new and the standard techniques.

A prototype database design system is presented. The system is object oriented in two ways. First, a uniform object-message paradigm is used for the design, definition, and manipulation language. Second, the structure of the underlying system is object oriented and is being implemented in Smalltalk-80.

We present a design system shell which can be used to experiment with principles of design and be used as a design tool where complex layers of information need to be specified about objects, such as in database design. The shell can be tailored to a variety of application areas. It is object-oriented in its implementation and structure. Objects and messages are used as the specification language. The basic ingredients of a rule-based production system are provided, with rules treated as objects and defined independently of the classes to which they are applied.