Hierarchical scheduling in an intelligent environmental control system

This paper describes the design and implementation of a hierarchical scheduling subsystem and graphical user interface in an intelligent environmental control system. The hierarchical scheduling system is capable of managing all environmental events occurring in widely different time scales as specified by the user. We employ a knowledge representation scheme called a system entity structure to specify the environmental schedules in a hierarchical fashion. A system entity structure called TAL (Timed Action Language) is developed. TAL organizes a family of all possible long-/mid-/short-term schedules from which a specific schedule can be pruned by the user through graphical interface.