Local Search for Planning and Scheduling -

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Résumé :
Thenextsetofarticlesdealwithplanningsystemsthatareabletoinc- porateresourcereasoning. The?rstarticle,ofwhichIamtheauthor,makesit clearwhyconventionalplanningsystemscannotproperlyhandleplanningwith resourcesandgivesanoverviewoftheconstraint-basedExcaliburagent?spl- ningsystem,whichdoesnothavetheserestrictions. Thenextthreearticlesare aboutNASAJPL?sASPEN/CASPERsystem. The?rstone?byChien,Knight, andRabidea?focusesonthereplanningcapabilitiesoflocalsearchmethods, presentingtwoempiricalstudiesinwhichacontinuousplanningprocessclearly outperformsarestartstrategy. Thenextarticle,byEngelhardtandChien,shows howlearningcanbeusedtospeedupthesearchforaplan. Thegoalisto?nda setofsearchheuristicsthatguidethesearchaswellaspossible. Thelastarticle inthisblock?byKnight,Rabideau,andChien?proposesanddemonstrates, a technique for aggregating single search moves so that distant states can be reachedmoreeasily. VI Preface Thelastthreearticlesinthisbookaddresstopicsthatarenotdirectlyrelated tolocalsearch,butthedescribedmethodsmakeverylocaldecisionsduringthe search. RefanidisandVlahavasdescribeextensionstotheGRTplanner,e. g. ,a hill-climbingstrategyforactionselection. Theextensionsresultinmuchbetter performancethanwiththeoriginalGRTplanner. Thesecondarticle?byO- india, Sebastia, and Marzal ? presents a planning algorithm that successively re?nes a start graph by di?erent phases, e. g. , a phase to guarantee comp- teness. Inthelastarticle,HiraishiandMizoguchipresentasearchmethodfor constructingaroutemap. Constraintswithrespecttomemoryandtimecanbe incorporatedintothesearchprocess. Iwishtoexpressmygratitudetothemembersoftheprogramcommittee, whoactedasreviewersfortheworkshopandthisvolume. Iwouldalsoliketo thank all those who helped to make this workshop a success ? including, of course,theparticipantsandtheauthorsofpapersinthisvolume. June2001 AlexanderNareyek WorkshopChair ProgramCommittee EmileH. L. Aarts PhilipsResearch Jos?eLuisAmbite Univ. ofSouthernCalifornia BlaiBonet Universityof

Sommaire:
Invited Paper.- Meta-heuristics: The State of the Art.- Combinatorial Optimization.- Solving the Sports League Scheduling Problem with Tabu Search.- Lagrange Multipliers for Local Search on Planning Graphs.- Planning with Resources.- Beyond the Plan-Length Criterion.- An Empirical Evaluation of the Effectiveness of Local Search for Replanning.- Board-Laying Techniques Improve Local Search in Mixed Planning and Scheduling.- Empirical Evaluation of Local Search Methods for Adapting Planning Policies in a Stochastic Environment.- Related Approaches.- The GRT Planner: New Results.- Incremental Local Search for Planning Problems.- Map Drawing Based on a Resource-Constrained Search for a Navigation System....