Constructive stochastic temporal reasoning in situation assessment

Due to poor structure of situation assessment tasks (SA-tasks), the knowledge-based approach has been studied intensively by many authors. But little progress up to now has been achieved because the existing techniques usually neglect the constructive nature of a human expert´s reasoning in a process of a SA-task solving. The development of a new method enabling one to model constructive reasoning is rather complicated, the scope of this work has been restricted to the temporal aspect only. In the paper, a mathematical framework, which may be used in a rule-based expert system, reasoning about events in a constructive manner, is presented. Time instances and intervals are treated in detail, using a stochastic approach to represent imprecision. The human expert´s temporal knowledge is considered imprecise in the stochastical sense, as well. Both forward and backward modes of reasoning are studied. Sufficient conditions for consistency of the knowledge model are also derived. The method has been implemented by the author in a feasibility demonstration prototype expert system