### Abstract

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.

Original language | English (US) |
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Title of host publication | Proceedings - International Conference on Data Engineering |

Publisher | Publ by IEEE |

Pages | 335-343 |

Number of pages | 9 |

ISBN (Print) | 0818635703 |

State | Published - 1993 |

Event | 1993 IEEE 9th International Conference on Data Engineering - Vienna, Austria Duration: Apr 19 1993 → Apr 23 1993 |

### Other

Other | 1993 IEEE 9th International Conference on Data Engineering |
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City | Vienna, Austria |

Period | 4/19/93 → 4/23/93 |

### Fingerprint

### ASJC Scopus subject areas

- Software
- Engineering(all)
- Engineering (miscellaneous)

### Cite this

*Proceedings - International Conference on Data Engineering*(pp. 335-343). Publ by IEEE.

**Valid-time indeterminacy.** / Dyreson, Curtis E.; Snodgrass, Richard Thomas.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*Proceedings - International Conference on Data Engineering.*Publ by IEEE, pp. 335-343, 1993 IEEE 9th International Conference on Data Engineering, Vienna, Austria, 4/19/93.

}

TY - GEN

T1 - Valid-time indeterminacy

AU - Dyreson, Curtis E.

AU - Snodgrass, Richard Thomas

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.

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

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

M3 - Conference contribution

SN - 0818635703

SP - 335

EP - 343

BT - Proceedings - International Conference on Data Engineering

PB - Publ by IEEE

ER -