The paper considers an ontological approach to describing the interaction of information processes in intelligent systems. A hierarchical family of ontologies is proposed that investigate both fundamental aspects of representing temporal entities in knowledge bases of intelligent systems and higher-level aspects related to describing the interaction of information processes. The hierarchy of such processes from the processes performed within the hardware platform to the processes of problem solving within a distributed system of agents is considered. Approaches to synchronization of such processes are considered. Special attention is paid to the ontology of spatio-temporal entities, which specifies the semantics of concepts describing changes in various entities in time, such as events, situations, cause-and-effect relations, and so on. Of the three levels of information processes, the paper discusses in the most detail the lower level related to the interpretation of information processes within the hardware platform. Two approaches to organizing of the such interpretation are considered.