Hybrid temporal reasoning
Jürgen Dorn · 1994
. In this paper a framework for the combination of qualitative and metric temporal knowledge is presented. It is intended especially for technical applications with real-time requirements and was applied to several scheduling problems. For realistic applications in such domains one has to consider uncertainty and vagueness of temporal knowledge. The proposed representation has the full expressiveness of Allen's interval algebra and allows additionally the specification of exact and/or uncertain metric knowledge. The metric time is represented by discrete units. This time can be unknown or restricted to a continuous range of values. However, one has to distinguish how the range is interpreted. There is uncertainty coming from the incompleteness of knowledge about the future and vagueness due to the uncertainty of durations in the technical process. The qualitative and metric temporal knowledge is stored in one graph and all possible inferences between them are propagated without loss of information. The transitivity table for interval relations given originally by Allen is changed slightly since intervals of duration zero are allowed. The applied propagation algorithm achieves path consistency. 1