Representation of structured events and efficient procedures for their recognition

摘要

Structured events are configurations of objects in logical, spatial, temporal or activity relations. A parameterized structural representation system for this class of events is discussed. Parameters in such representations are arbitrarily chosen symbols used to insure consistent references to the same object in diverse relations. All-or-none matching of two representations is the basis for pattern recognition. In this framework, descriptions of pattern or concept prototypes act as structural templates for stimuli. As a result, recognition can be performed in a natural and structural way and is unaffected by manipulations of irrelevant variables. Typical recognition procedures are reviewed and a variety of alternative approaches are considered in light of the potential combinatorial explosions which might arise in applications of these procedures. One alternative is proposed which can exploit both redundancy among partially matching templates and computational parallelism in exhaustive search (recognition) problems. Another possibility considered is to find special recognition procedures for particular recognition problems. For example, to accomplish word recognition in speech understanding systems, highly practical techniques exist to match many templates in parallel (simultaneously) using only simple bit string operations. In addition, both the possibility of additional heuristic approaches to general recognition procedures and the use of less general relational representations are also considered in this paper.