Abstract

Time-Oriented Queries: The Tzolkin System John H. Nguyen, Yuval Shahar, Samson W. Tu, Amar K. Das, and Mark A. Musen Stanford Medical Informatics, Stanford University School of Medicine Stanford, CA 94305-5479 John H. Nguyen (corresponding author) Stanford Medical Informatics Medical School Office Building X-215 251 Campus Drive Stanford University Stanford, CA 94305-5479 Voice: +1-650-725-3399 Fax: +1-650-725-7944 Email: jnguyen@smi.stanford.edu Yuval Shahar Email: shahar@smi.stanford.edu Samson W. Tu Email: tu@smi.stanford.edu Amar K. Das Email: das@smi.stanford.edu Mark A. Musen Email: musen@smi.stanford.edu Abstract The ability to reason with time-oriented data is central to the practice of medicine. Monitoring clinical variables over time often provides information that drives medical decision making (e.g., clinical diagnosis and therapy planning). Because the time-oriented patient data are often stored in electronic databases, it is important to ensure that clinicians and medical decision-support applications can conveniently find answers to their clinical queries using these databases. To help clinicians and decision-support applications make medical decisions using time-oriented data, a database-management system should (1) permit the expression of abstract, time-oriented queries, (2) permit the retrieval of data that satisfy a given set of time-oriented data-selection criteria, and (3) present the retrieved data at the appropriate level of abstraction. We impose these criteria to facilitate the expression of clinical queries and to reduce the manual data processing that users must undertake to decipher the answers to their queries. We describe a system, Tzolkin, that integrates a general method for temporal-data maintenance with a gener...

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