CAPSUL: A constraint-based specification of repeating patterns in time-oriented data

We use a constraint-based language to specify repeating temporal patterns. The Constraint-based Pattern Specification Language (CAPSUL) is simple to use, but allows a wide variety of patterns to be expressed. This paper describes in detail the syntax of CAPSUL, including its layers of abstraction and four types of constraints. We also discuss the semantics of CAPSUL, including the concept of interference between patterns and the expressive power of the language. We have implemented CAPSUL in a temporal-abstraction system called Resume, and used it in a graphical knowledge-acquisition tool to acquire domain-specific knowledge from experts about patterns to be found in large databases. We summarize the results of preliminary experiments using the pattern-specification and pattern-detection tools on data about patients who have cancer and have been seen at the Rush Presbyterian/St. Luke's Medical Center.