Engineering time in medical knowledge-based systems through time-axes and time-objects

Starting from the premise that time representation and temporal reasoning must constitute integral aspects of a competent, knowledge-based, medical system, the paper presents the relevant requirements and discusses their realisation in terms of a generic temporal kernel to be embedded in such a system. The kernel has a layered architecture where the bottom layer gives the ontological primitives and their associated axioms, and the higher layers implement the required temporal reasoning. The principal primitives of the ontology are the time-axis and the time-object