The Experts below are selected from a list of 42903 Experts worldwide ranked by ideXlab platform
Tolga Bektas - One of the best experts on this subject based on the ideXlab platform.
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CIPLS - Balancing tour durations in routing a vehicle fleet
2013 IEEE Symposium on Computational Intelligence in Production and Logistics Systems (CIPLS), 2013Co-Authors: Tolga BektasAbstract:This paper is concerned with the multiple Traveling Salesman Problem (mTSP) with lower and upper bound constraints on tour durations. The paper presents a flow-based integer linear programming formulation of the problem and some valid inequalities. The paper also describes a Benders decomposition algorithm based on this model as an exact solution approach. Computational experimentation shows that the decomposition algorithm is able to improve the performance of a standard off-the-shelf solver in solving medium-scale instances of the problem up to 71 nodes and two salesmen. The paper also presents some results in solving a practical mobile library routing problem and discusses the implications of balancing tour durations.
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formulations and benders decomposition algorithms for multidepot salesmen problems with load balancing
European Journal of Operational Research, 2012Co-Authors: Tolga BektasAbstract:This paper describes new models and exact solution algorithms for the fixed destination multidepot salesmen problem defined on a graph with n nodes where the number of nodes each Salesman is to visit is restricted to be in a predefined range. Such problems arise when the time to visit a node takes considerably longer as compared to the time of travel between nodes, in which case the number of nodes visited in a Salesman’s tour is the determinant of their ‘load’. The new models are novel multicommodity flow formulations with O(n2) binary variables, which is contrary to the existing formulations for the same (and similar) problems that typically include O(n3) binary variables. The paper also describes Benders decomposition algorithms based on the new formulations for solving the problem exactly. Results of the computational experiments on instances derived from TSPLIB show that some of the proposed algorithms perform remarkably well in cases where formulations solved by a state-of-the-art optimization code fail to yield optimal solutions within reasonable computation time.
Paolo Toth - One of the best experts on this subject based on the ideXlab platform.
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a branch and cut algorithm for the symmetric generalized traveling Salesman problem
Operations Research, 1997Co-Authors: Matteo Fischetti, Juan Jose Salazar Gonzalez, Paolo TothAbstract:We consider a variant of the classical symmetric Traveling Salesman Problem in which the nodes are partitioned into clusters and the Salesman has to visit at least one node for each cluster. This NP-hard problem is known in the literature as the symmetric Generalized Traveling Salesman Problem (GTSP), and finds practical applications in routing, scheduling and location-routing. In a companion paper (Fischetti et al. [Fischetti, M., J. J. Salazar, P. Toth. 1995. The symmetric generalized traveling Salesman polytope. Networks 26 113–123.]) we modeled GTSP as an integer linear program, and studied the facial structure of two polytopes associated with the problem. Here we propose exact and heuristic separation procedures for some classes of facet-defining inequalities, which are used within a branch-and-cut algorithm for the exact solution of GTSP. Heuristic procedures are also described. Extensive computational results for instances taken from the literature and involving up to 442 nodes are reported.
Sukkasem Suratanakavikul - One of the best experts on this subject based on the ideXlab platform.
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a systems thinking approach to the study of side effect of performance system in insurance company
2013Co-Authors: Sukkasem SuratanakavikulAbstract:Nowadays, there is a tendency towards using performance system in most of corporations and organizations. Up to now, scholars research are only focus on how to formulate the performance system, key measurable indicators, how to quantify, the relationship of performance system and staffsâ efficiency, key performance indicators, the advantages of performance system, the precautions of performance system and so on. However, the side-effects of performance system are obvious and there are few research study on this part. This research uses literature collection method and interviews method to collect and understand that performance system affect on some insurance company. Then investigating the effects of the using performance system in insurance company in system thinking approach. This research found that Salesman would only focus on selling insurances and not concerned with claims part which because there is no incentives. Under this kind of performance system would gain pressure on salesmen which make them abdicate or declining their ethic. This study suggests that the insurance company have to understand of the importance of how to maintain dynamically align principles which make the insurance company operating much better, and reduces the side-effect From using performance system.
Luigi Laura - One of the best experts on this subject based on the ideXlab platform.
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The on-line asymmetric traveling Salesman problem
Journal of Discrete Algorithms, 2008Co-Authors: Giorgio Ausiello, Vincenzo Bonifaci, Luigi LauraAbstract:We consider two on-line versions of the asymmetric traveling Salesman problem with triangle inequality. For the homing version, in which the Salesman is required to return in the city where it started from, we give a 3+52-competitive algorithm and prove that this is best possible. For the nomadic version, the on-line analogue of the shortest asymmetric Hamiltonian path problem, we show that the competitive ratio of any on-line algorithm depends on the amount of asymmetry of the space in which the Salesman moves. We also give bounds on the competitive ratio of on-line algorithms that are zealous, that is, in which the Salesman cannot stay idle when some city can be served.
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WADS - The on-line asymmetric traveling Salesman problem
Lecture Notes in Computer Science, 2005Co-Authors: Giorgio Ausiello, Vincenzo Bonifaci, Luigi LauraAbstract:We consider two on-line versions of the asymmetric traveling Salesman problem with triangle inequality. For the homing version, in which the Salesman is required to return in the city where it started from, we give a $\frac{3\sqrt{5}}{2}$ -competitive algorithm and prove that this is best possible. For the nomadic version, the on-line analogue of the shortest asymmetric hamiltonian path problem, we show that the competitive ratio of any on-line algorithm has to depend on the amount of asymmetry of the space in which the Salesman moves. We also give bounds on the competitive ratio of on-line algorithms that are zealous, that is, in which the Salesman cannot stay idle when some city can be served.
Vikas Kumar - One of the best experts on this subject based on the ideXlab platform.
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International direct marketing efforts: Are they useful to small businesses in establishing consistent patterns of exporting?
Journal of Direct Marketing, 1991Co-Authors: Nancy D. Albers, Vikas KumarAbstract:Understanding the effectiveness of various marketing efforts in the international marketplace is a growing need for United States businesses. Unfortunately, many businesses, especially small ones are not consistently successful in exporting their products. Although many factors can contribute to exporting on a consistent basis, this study analyzes the various international marketing methods utilized by small businesses and determines which methods, especially direct marketing, can significantly contribute to consistent exporting of products. The data used in the study are provided by small businesses in the United States, and a logit choice model is formulated. Among various marketing methods, direct marketing is found to be a significant predictor of exporting on a consistent basis, in addition to such factors as prior experience and extent of preparation to enter foreign markets. Further analysis revealed that among the direct marketing approaches, both the letter and Salesman campaigns were found to be more effective than the phone campaign. Therefore, direct marketing efforts may be targeted toward more efficient approaches, such as developing contacts through mail and salesmen.
