James Clifford

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Knowledge discovery in databases presents many interesting challenges within the ¢onte~t of providing computer tools for exploring large data archives. Electronic data .repositories are growing qulckiy and contain data from commercial, scientific, and other domains. Much of this data is inherently temporal, such as stock prices or NASA telemetry data.(More)
This document contains definitions of a wide range of concepts specific to and widely used within temporal databases. In addition to providing definitions, the document also includes separate explanations of many of the defined concepts. Two sets of criteria are included. First, all included concepts were required to satisfy four relevance criteria, and,(More)
Numerous proposals for extending the relational data model to incorporate the temporal dimension of data have appeared in the past several years. These proposals have differed considerably in the way that the temporal dimension has been incorporated both into the <italic>structure</italic> of the extended relations of these temporal models and into the(More)
In search of the appropriate semantics -for the inclusion of structures and operations that ~111 meet the needs of a wide class of users interested in a database system supporting temporal views of their data, the paper includes both a discussion of many problems that must be addressed, and a proposal for an extended relational algebra The informal(More)
This docuinent specifies a temporal extension to the SQL-92 language standard. The language is designated TSQLZ. The document is organized as follows. The next section indicates the starting point of the design, the SQL92 language. Section 4 lists the desired features on which the TSQL2 Language Design Committee reached consensus. Section 5 presents the(More)
This document contains de nitions of a wide range of concepts speci c to and widely used within temporal databases. In addition to providing de nitions, the document also includes explanations of concepts as well as discussions of the adopted names. The consensus e ort that lead to this glossary was initiated in Early 1992. Earlier versions appeared in(More)
Critical to the design of an historical database model is the representation of the &#x201C;existence&#x201D; of objects across the temporal dimension &#x2014; for example, the &#x201C;birth,&#x201D; &#x201C;death,&#x201D; or &#x201C;rebirth&#x201D; of an individual, or the establishment or dis-establishment of a relationship. The notion of the(More)
The concept of a historical database is introduced as a tool for modeling the dynamic nature of some part of the real world. Just as first-order logic has been shown to be a useful formalism for expressing and understanding the underlying semantics of the relational database model, intensional logic is presented as an analogous formalism for expressing and(More)