Minimum concave cost multicommodity network design

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Elektrik ve Elektronik Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2005

Öğrenci: FATİH SAY

Danışman: CÜNEYT FEHMİ BAZLAMAÇCI

Özet:

Minimum Concave Cost Multicommodity Network Design Problem arises in many application areas, such as transportation planning, distributed energy system and especially both circuit and packet switching backbone network design. Exact concave optimization algorithms have been developed, but these methods are applicable if the network size is small. Therefore, these problems are usually solved by non-exact iterative methods. In this thesis work, methods proposed for circuit switching and packet switching network design are evaluated in detail. After a comprehensive literate survey, Yaged̕s Linearization, Minoux greedy and Minoux accelerated greedy methods are found to be applicable to circuit switching network design when both solution quality and computational time is considered. Previously, it has been found that Minoux greedy methods may create routings with cycles and in order to eliminate these cycles a modification has been proposed. In this work, this modification is extended and evaluated in detail. Similarly, Gerla and Kleinrock̕s Concave Branch Elimination, Gersht̕s greedy and Stacey̕s Concave Link Elimination methods are investigated within the context of packet switching network design. All of these methods consider aggregate flows on each link simultaneously re-routing more than one commodity in one step. This thesis work also considers an alternative disaggregate approach, where only one commodity is handled at a time. Finally, algorithms proposed for circuit switching network design problem are adapted to the packet switching case and an extensive comparative computational study is performed to point out the best method with respect to time and solution quality for a number of networks and cost structure. Computational results have shown that modification on Minoux greedy to eliminate cycles leads to considerable improvements and the disaggregate approach