A theoretical model for crisp and fuzzy time

Based on the way time is expressed in natural language, as was studied in the linguistic part of our research, it is observed that time indications usually are rather approximative and situated within the context of the traditional hierarchical time unit system, thereby choosing the most appropriate level of detail. In this paper we present a model for temporal data which aims at being both as flexible and as general as possible. Flexibility is obtained by the use of fuzzy set theory and of granularities which brings the model very close to its natural language counterpart. Generality is achieved by the dynamic aspect of the granularity structure and by the support of spans, time points and intervals, absolute and relative time, aperiodic as well as periodic time elements.

[1]  Didier Dubois,et al.  Timed possibilistic logic , 1991, Fundam. Informaticae.

[2]  Lotfi A. Zadeh,et al.  Fuzzy logic = computing with words , 1996, IEEE Trans. Fuzzy Syst..

[3]  D. Mitra,et al.  A possibilistic interval constraint problem: fuzzy temporal reasoning , 1994, Proceedings of 1994 IEEE 3rd International Fuzzy Systems Conference.

[4]  Didier Dubois,et al.  Processing fuzzy temporal knowledge , 1989, IEEE Trans. Syst. Man Cybern..

[5]  G. De Tre,et al.  Towards temporal fuzzy and uncertain object-oriented database management systems , 1997, 1997 Annual Meeting of the North American Fuzzy Information Processing Society - NAFIPS (Cat. No.97TH8297).

[6]  Abraham Silberschatz,et al.  Database research faces the information explosion , 1997, CACM.

[7]  Filip Devos,et al.  Fuzzy Time Expressions in Natural Language Queries , 1994, FQAS.

[8]  Arie Segev,et al.  A consensus glossary of temporal database concepts , 1994, SIGMOD 1994.

[9]  llsoo Ahn,et al.  Temporal Databases , 1986, Computer.

[10]  Nikolaj Zimic,et al.  Attention to time in fuzzy logic , 1996, Fuzzy Sets Syst..

[11]  Ramez Elmasri,et al.  A consensus glossary of temporal database concepts , 1994, SGMD.

[12]  Patrick Bosc,et al.  Flexible querying and temporal databases , 1996, Other Conferences.

[13]  James F. Allen.  Maintaining knowledge about temporal intervals , 1983, CACM.

[14]  Patricia Maesfranckx,et al.  Vague lexical time indicators: their use in natural language and attempts to model them in computer databases , 1997 .

[15]  Sushil Jajodia,et al.  A general framework and reasoning models for time granularity , 1996, Proceedings Third International Workshop on Temporal Representation and Reasoning (TIME '96).

[16]  Drew McDermott,et al.  A Temporal Logic for Reasoning About Processes and Plans , 1982, Cogn. Sci..

[17]  Barbara Pernici,et al.  Automatic deduction of temporal information , 1992, TODS.