TY - GEN

T1 - Valid-time indeterminacy

AU - Dyreson, Curtis E.

AU - Snodgrass, Richard T.

PY - 1993/1/1

Y1 - 1993/1/1

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.

UR - http://www.scopus.com/inward/record.url?scp=0027316634&partnerID=8YFLogxK

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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 -