REPRESENTING AND DEVELOPING TEMPORALLY ABSTRACTED KNOWLEDGE AS A MEANS TOWARDS FACILITATING TIME MODELING IN MEDICAL DECISION-SUPPORT SYSTEMS

The utilization of the appropriate level of temporal abstraction is an important aspect of time modeling. We discuss some aspects of the rel ation of temporal abstraction to important knowledge engineering param eters such as model correctness, ease of model specification, knowledg e availability, query completeness, inference tractability, and semant ic clarity. We propose that versatile and efficient time-modeling form alisms should encompass ways to represent and reason at more than one level of abstraction, and we discuss such a hybrid formalism. Although many research efforts have concentrated on the automation of specific temporal abstractions, much research needs to be done in understandin g and developing provably optimal abstractions. We provide an initial framework for studying this problem in a manner that is independent of the particular problem domain and knowledge representation, and sugge st several research challenges that appear worth pursuing. (C) 1997 El sevier Science Ltd.