Browsing by Author "Ozkarahan, I"

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    A CONSTRAINT PROGRAMMING HEURISTIC FOR A HETEROGENEOUS VEHICLE ROUTING PROBLEM WITH SPLIT DELIVERIES
    Ozfirat, PM; Ozkarahan, I
    This article considers fresh goods distribution of a retail chain store in Turkey. The problem is formulated as a vehicle routing problem with a heterogeneous fleet for which no exact algorithm has ever been designed to solve it. A fast and effective algorithm based on constraint programming is proposed for the solution. The procedure is tested on some of the benchmark problems in literature. The real-life case is first solved assuming that delivery of a customer cannot be split between vehicles. Then it is resolved considering split deliveries. Solutions of both strategies are compared with the current performance of the firm to determine a distribution strategy. Results indicate considerable improvement in the performance of the firm.
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    Parallel machine scheduling with additional resources: Notation, classification, models and solution methods
    Edis, EB; Oguz, C; Ozkarahan, I
    Majority of parallel machine scheduling studies consider machine as the only resource. However, in most real-life manufacturing environments, jobs may require additional resources, such as automated guided vehicles, machine operators, tools, pallets, dies, and industrial robots, for their handling and processing. This paper presents a review and discussion of studies on the parallel machine scheduling problems with additional resources. Papers are surveyed in five main categories: machine environment, additional resource, objective functions, complexity results and solution methods, and other important issues. The strengths and weaknesses of the literature together with open areas for future studies are also emphasized. Finally, extensions of integer programming models for two main classes of related problems are given and conclusions are drawn based on computational studies. (C) 2013 Elsevier B.V. All rights reserved.