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dc.contributor.advisorWaller, S. Travis
dc.contributor.advisorMachemehl, Randy B.
dc.creatorKumar, Roshanen
dc.date.accessioned2015-03-16T13:03:24Zen
dc.date.issued2011-12en
dc.date.submittedDecember 2011en
dc.identifier.urihttp://hdl.handle.net/2152/29142en
dc.descriptiontexten
dc.description.abstractThe Vehicle Routing Problem (VRP) is a classical problem in logistics that has been well studied by the operations research and transportation science communities. VRPs are defined as follows. Given a transportation network with a depot, a set of pickup or delivery locations, and a set of vehicles to service these locations: find a collection of routes starting and ending at the depot, such that (i) the customer's demand at a node is satisfied by exactly one vehicle, (ii) the total demand satisfied by a vehicle does not exceed its capacity, and (iii) the total distance traveled by the vehicles is minimized. This problem is especially hard to solve because of the presence of sub--tours, which can be exponential in number. In this dissertation, a special case of the VRP is considered -- where the underlying network has a tree structure (TVRP). Such tree structures are found in rural areas, river networks, assembly lines of manufacturing systems, and in networks where the customer service locations are all located off a main highway. Solution techniques for TVRPs that explicitly consider their tree structure are discussed in this dissertation. For example, TVRPs do not contain any sub-tours, thereby making it possible to develop faster solution methods. The variants that are studied in this dissertation include TVRPs with Backhauls, TVRPs with Heterogeneous Fleets, TVRPs with Duration Constraints, and TVRPs with Time Windows. Various properties and observations that hold true at optimality for these problems are discussed. Integer programming formulations and solution techniques are proposed. Additionally, heuristic methods and conditions for lower bounds are also detailed. Based on the proposed methodology, extensive computational analysis are conducted on networks of different sizes and demand distributions.en
dc.format.mimetypeapplication/pdfen
dc.subjectVehicle routingen
dc.subjectTree networksen
dc.subjectBackhaulsen
dc.subjectTime windowsen
dc.subjectInteger programmingen
dc.subjectHeuristicsen
dc.subjectCPLEXen
dc.subjectWarm starten
dc.titleThe vehicle routing problem on tree networks : exact and heuristic methodsen
dc.typeThesisen
dc.date.updated2015-03-16T13:03:24Zen
dc.description.departmentCivil, Architectural, and Environmental Engineeringen
thesis.degree.departmentCivil, Architectural, and Environmental Engineeringen
thesis.degree.disciplineCivil Engineeringen
thesis.degree.grantorThe University of Texas at Austinen
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophyen


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