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Verimag@Ametist

Verimag@Ametist. Oded Maler December 2002. Major Work Directions. SAT Solving for Difference Logic Axxom case-study Scheduling with Timed Automata. SAT for Difference Logic.

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Verimag@Ametist

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  1. Verimag@Ametist Oded Maler December 2002

  2. Major Work Directions • SAT Solving for Difference Logic • Axxom case-study • Scheduling with Timed Automata

  3. SAT for Difference Logic • The first prototype of the solver has been implemented (Moez Mahfoudh, collaboration with E. Asarin, M Bozga and P. Niebert (Marseille)) with some translations from TA and other problems. • Expected breakthrough: April 2003 or never..

  4. Axxom Case-Study • Two directions: • Treat the case-study itself – Marius Bozga using IF • Reach it gradually as extending the basic job-shop problem (see later) • Expected results: Mars 2003

  5. Scheduling Framework: Principles • Start with the cleanest problem (job-shop) • Model it with timed automata • Exploit the specific structure of the problem to have better algorithms • Add general- and special-purpose heuristics • Test on benchmarks • Move on to more complex problems • (Thesis of Yasmina Abdeddaim, Nov 2002)

  6. So far it Works! • Job-shop problem (in the VHS project): discovery of the fact that for this problem you do not need the zone technology! • In fact you do not need it in a large class of problems • Investigation of “intelligent” search techniques • Respectable performance results

  7. Extensions • Job-shop with preemption (Ametist kick-off meeting): similar resuls, no zones, undecidability of stopwatch becomes irrelevant, good performance results • Task graph scheduling: partially-ordered tasks on parallel identical machines (with release times and deadlines) – talk by A. Kerbaa this meeting

  8. Further Extensions • Different machines with different speeds for each product – a preparation for the value chain problem (talk by A Kerbaa) • Parallel threads with resources and synchronization (preliminary work) • Non monotonicity (relative deadlines) • Scheduling under uncertainty (my talk)

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