Reports on a project showing that relational data models, including unnormalized models that allow the nesting of relations, cannot fully capture the structural properties of lexical information. A feature-based model that allows for a full representation of some nesting and defines a factoring mechanism is described and demonstrated. (38…

Suggests a unified concept of a lexical subsystem as part of an information system to deal with lexical problems in local and network environments. The linguistic and control functions of the lexical subsystems in solving problems for large computer systems are described, and references are included. (Author/BK)

Describes the National Aeronautics and Space Administration (NASA) Lexical Dictionary (NLD), a machine-aided indexing system used online at the NASA Center for AeroSpace Information (CASI). The functions of NLD system components are described in detail, and production and quality benefits resulting from machine-aided indexing at CASI are…

Important characteristics of lexical databases and their applications in information retrieval and natural language processing are explained. An ongoing project using various machine-readable sources to build a lexical database is described, and detailed designs of individual entries with examples are included. (Contains 66 references.) (EAM)