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RESEARCH PRODUCT

Some recent contributions to routing and location problems

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CORAL 2003, a Conference on Routing and Location, washeld in Puerto de la Cruz (Tenerife, Spain) from February24–26, 2003. A wonderful place, close to the black sand ofthe beach, and a nice temperature welcomed a group ofsenior and young researchers from Canada, England,France, Germany, and Spain. Social activities were alsoprovided and sponsored by the Cabildo Insular de Tenerife(the local government) and TITSA (the public bus transpor-tation company on the island). The conference corre-sponded to the third annual meeting of a research project,funded by the Spanish Ministry of Science and Technology,developing a Decision Support System for Vehicle Routingand Facility Location Problems (SADERYL, TIC-2000-1750-C06), in which research groups from six Spanishuniversities are collaborating. The conference was open toother participants and it was a pleasure to attend presenta-tions by G. Laporte (CRT, Montreal), A. Letchford (Uni-versity of Lancaster), J. Pacheco (University of Burgos), C.Prins (University of Troyes), G. Reinelt and D. Theis (Uni-versity of Heidelberg), and F. Semet (University of Valen-ciennes). Although the conference focused on routing andlocation problems, other optimization problems were alsoconsidered. Updated information, as well as the extendedabstracts of the presentations, can be found at the followingsite: http://webpages.ull.es/users/saderyl/Coral.htm.The SADERYL project is based on a global understand-ing of the logistics chain and its requirements for an effi-cient management. The decision problems arising in theintegrated management of the logistics chain can be classi-fied as strategic, tactical, and operational problems. Withinthe SADERYL project, we have focused mainly on thestrategic and tactical aspects, concerning routing, location,and combined location-routing problems. All these prob-lems are of great economic interest and the use of combi-natorial optimization-based packages for their managementhas proved to produce substantial savings. However, a muchdeeper understanding of these problems is needed to im-prove the quantitative tools that should be provided to themanagers as a basis for making their decisions. ThroughCORAL 2003, we have tried to contribute to this objectivewith some papers giving more theoretical insights, model-ing approaches, and heuristic and exact algorithms for theseproblems.This report highlights the main results presented at theconference. To give a quick overview, the presentationshave been grouped into four areas: routing problems (gen-eral, arc routing, and node routing), combined location-routing problems, pure location problems, and other topics.On general routing, Dirk Theis [20] showed new resultson “The Undirected General Routing Problem.” This prob-lem, GRP, is a generalization of the well-known RuralPostman Problem (RPP) in which, besides a set of requirededges, a set of nodes is also required to be visited by the“postman.” Most of the previous results for the RPP/GRP