Oded Maler December 2002

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

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..

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

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)

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

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

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)