Utility Accrual Scheduling of Distributable Threads: The Tempus Approach

Abstract : Dynamic, adaptive, real-time embedded control systems are present at any level(s) of an enterprise e.g., devices in the defense domain such as multi-mode phased array radars and battle management. These embedded systems often include "soft" as well as "hard" time constraints. Jensen's time/utility functions 4 (or TUFs) allow the semantics of soft time constraints to be precisely specified. A TUF specifies the utility to the system, resulting form the completion of an activity, as a function of the its completion time. Figure 1 shows examples of TUF time constraints. TUFs have been successfully used in two significant, real-time applications, including an AWACS (Airborne WArning and Control System) surveillance mode tracker system built by MITRE and Open Group, and a coastal air defense system built by CMU and General Dynamics.