PRC Inc.: description of the Paktus system used for MUC-4

The PRC Adaptive Knowledge-based Text Understanding System (PAKTUS) has been under development as an Independent Research and Development project at PRC since 1984. It includes a core English lexicon and grammar, a concept network, processes for applying these to lexical, syntactic, semantic, and discourse analysis, and tools that support the adaptation of the generic core to new domains, primarily by acquiring sublanguage and domain-specific lexicon and conceptual topic patterns of interest. The lexical, syntactic, and semantic analysis components were completed before MUC-4 and required little adaptation. The discourse analysis component is new and was completed in the course of applying the system to MUC-4, although it is generic. The overall system is described in [1]. The present description concentrates on discourse analysis.