Proposes a model of knowledge-based information retrieval (KBIR) that is based on a hierarchical concept graph (HCG) which shows relationships between index terms and constitutes a hierarchical thesaurus as a knowledge base. Conceptual distance between a query and an object is discussed and the use of Boolean operators is described. (25…

Proposes a criterion for selecting a sequence of objectives from a learning hierarchy and describes a sequence generating algorithm which is designed to generate a minimal memory load sequence from a learning tree. Its effectiveness in generating low memory load sequences from hierarchies that are not trees is also discussed. (RP)