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Title page for ETD etd-12032003-215921


Type of Document Master's Thesis
Author Prabhakar, Ramadass
URN etd-12032003-215921
Title Scheduling in time triggered systems under mode changes
Degree Master of Science
Department Electrical Engineering
Advisory Committee
Advisor Name Title
Gabor Karsai Committee Chair
Benoit Dawant Committee Member
Keywords
  • mode changes
  • scheduling
  • constraint programming
  • time triggered systems
Date of Defense 2003-11-26
Availability unrestricted
Abstract
This thesis presents the use of constraint programming for scheduling tasks in time triggered real time systems undergoing mode changes. The scheduling problem is initially decomposed into schedules for individual modes, and then the schedules generated for each operational mode are processed to maintain timing constraints across mode changes. These mode changes are allowed to occur at particular time instants specified by the designer. A mode change task, in effect, acts as a placeholder for these time instants and different heuristics are proposed to set the period of the mode change tasks. A mode change schedule, which is the new schedule that needs to be executed when a mode change occurs, can be subsequently generated. Constraint programming has previously been used to solve scheduling problems, but until now there have been few attempts to solve the mode change problem using this technique.

An example of schedule generation with mode changes in an aircraft control system is shown.

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