TY - GEN
T1 - Valid-time indeterminacy
AU - Dyreson, Curtis E.
AU - Snodgrass, Richard T.
PY - 1993
Y1 - 1993
N2 - In valid-time indeterminacy, it is known that an event stored in a temporal database did in fact occur, but it is not known exactly when the event occurred. We present an extension of the tuple-timestamped temporal data model, called the possible chronons data model, to support valid-time indeterminacy. In the possible chronons data model, each event is represented with a set of possible chronons, delimiting when the event might have occurred, and a probability distribution over that set. We extend the TQuel query language with constructs that specify the user's credibility in the underlying valid-time data and the user's plausibility in the relationships among that data. We outline a formal tuple calculus semantics, and show that this semantics reduces to the determinate semantics on determinate data.
AB - In valid-time indeterminacy, it is known that an event stored in a temporal database did in fact occur, but it is not known exactly when the event occurred. We present an extension of the tuple-timestamped temporal data model, called the possible chronons data model, to support valid-time indeterminacy. In the possible chronons data model, each event is represented with a set of possible chronons, delimiting when the event might have occurred, and a probability distribution over that set. We extend the TQuel query language with constructs that specify the user's credibility in the underlying valid-time data and the user's plausibility in the relationships among that data. We outline a formal tuple calculus semantics, and show that this semantics reduces to the determinate semantics on determinate data.
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M3 - Conference contribution
AN - SCOPUS:0027316634
SN - 0818635703
T3 - Proceedings - International Conference on Data Engineering
SP - 335
EP - 343
BT - 1993 IEEE 9th International Conference on Data Engineering
PB - Publ by IEEE
T2 - 1993 IEEE 9th International Conference on Data Engineering
Y2 - 19 April 1993 through 23 April 1993
ER -