Extending nonmonotonic description logic with temporal aspects

This paper is about extending nonmonotonic description logic with temporal aspects; this attempt permits actually to represent both default and temporal features in concepts definition. The introduction of defaults in the definition of concepts in previous researches has allowed to go beyond the strict limitations on their description and permitted consequently to fully define them; by providing both necessary and sufficient conditions for their representation. This allowed improving the classification process. Contrary to the use of strict knowledge that provides only necessary conditions leaving the concepts partially defined. The nonmonotonic language that allows using defaults in the definition of concepts is AL augmented with default and exception connectors that allow respectively representing default and exception properties in concepts definition. However we frequently need to add the temporal aspect to the nonmonotonic feature as it is the case in causal reasoning, planning process, and action theory. In our case, we will use it in the field of access control. Our aim in this paper is to extend this logic further with temporal connectives to grant the possibility to represent temporal properties of concepts and that by referring to temporal description logic.