The purpose of this paper is to point out that if there are some machines that do not process any job then the mathematical programming model provided by Eren and Guner (Int J Adv Manuf Technol 40:1202-1205, 2009) may...
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The purpose of this paper is to point out that if there are some machines that do not process any job then the mathematical programming model provided by Eren and Guner (Int J Adv Manuf Technol 40:1202-1205, 2009) may not be a valid one.
The purpose of this paper is to point out some errors in Eren [Applied mathematicalmodelling, 33 (2009) 1141-1150]. We also suggest some methods to fix them. (C) 2011 Elsevier Inc. All rights reserved.
The purpose of this paper is to point out some errors in Eren [Applied mathematicalmodelling, 33 (2009) 1141-1150]. We also suggest some methods to fix them. (C) 2011 Elsevier Inc. All rights reserved.
In this paper, we present a novel decision support system for order acceptance/rejection in a hybrid Make-to-Stock/Make-to-Order production environment. The proposed decision support system is comprised of five steps....
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In this paper, we present a novel decision support system for order acceptance/rejection in a hybrid Make-to-Stock/Make-to-Order production environment. The proposed decision support system is comprised of five steps. At the first step, the customers are prioritized based on a fuzzy TOPSIS method. Rough-cut capacity and rough-cut inventory are calculated in the second step and in case of unavailability in capacity and materials, some undesirable orders are rejected. Also, proper decisions are made about non-rejected orders. At the next step, prices and delivery dates of the non-rejected orders are determined by running a mixed-integer mathematical programming model. At the fourth step, a set of guidelines are proposed to help the organization negotiate over price and due date with the customers. In the next step, if the customer accepts the offered price and delivery date, the order is accepted and later considered in the production schedule of the shop floor, otherwise the order is rejected. Finally, numerical experiments are conducted to show the tractability of the applied mathematical programming model. (C) 2010 Elsevier Inc. All rights reserved.
Protected areas in the European Union under the Natura 2000 reserve system cover about 17 percent of the total land area. Systematic evaluations of the effectiveness of the current reserve system have been scarce and ...
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Protected areas in the European Union under the Natura 2000 reserve system cover about 17 percent of the total land area. Systematic evaluations of the effectiveness of the current reserve system have been scarce and restricted to regional assessments. One reason for that may be the poor availability of comprehensive fine scale biodiversity data for the highly fragmented and densely human-populated European continent. We apply recently developed modeling tools for systematic conservation planning to conduct a detailed gap analysis using coarse scale species occurrence data. The employed mathematicalmodel uses mixed integer programming to determine the cost-minimizing distribution of habitat locations subject to biophysical, economic, and policy restrictions. We include fine scale wetland habitat data as well as species-specific proxies for population density and viable population threshold. First, we evaluate the performance of the current Natura 2000 system in covering endangered wetland vertebrate species. Results show that five area-demanding vertebrates are not covered by the current reserve system. Second, we identify potentials for expanding the network to move toward complete coverage for the considered species mostly in countries of North-Eastern Europe. About 3 million hectares of additional reserve area at a cost of 107 million Euro per year would be required to achieve coverage of all considered species. Third, we present spatially explicit priority regions for a cost-effective expansion of the current reserve network.
This paper evaluates the preferences of cantonal politicians for future agricultural land-use scenarios in a rural region of the Swiss lowlands. We combine results from a choice experiment with the outcome of a mathem...
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This paper evaluates the preferences of cantonal politicians for future agricultural land-use scenarios in a rural region of the Swiss lowlands. We combine results from a choice experiment with the outcome of a mathematical programming model. As a result, we define cost-efficient future land-use scenarios which would find acceptance in the cantonal parliament. Our study indicates that the level of agricultural production associated with the extent of environmental goods and services in these land-use scenarios is a crucial issue in the political acceptance and thus in the design of green payments for agriculture.
Background: Diabetes mellitus brings an increased risk for cardiovascular complications and patients profit from prevention. This prevention also suits the general population. The question arises what is a better stra...
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This paper discusses the newly defined planar storage location assignment problem (PSLAP). We develop a mathematical programming model and GA-based and dynamic PSLAP heuristic algorithms for the solving procedure. Usi...
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This paper discusses the newly defined planar storage location assignment problem (PSLAP). We develop a mathematical programming model and GA-based and dynamic PSLAP heuristic algorithms for the solving procedure. Using the testing set, we compare the performance of GA-based and dynamic PSLAP heuristic algorithms. The mathematical programming model is utilized as a comparison criterion. The comparison results demonstrate that the dynamic PSLAP heuristic algorithm performs better than the other solving procedures. In addition, we describe simulation experiments conducted to investigate the effects of stock yard layout and production schedule instability on the operation of the block stock yard. (C) 2009 Elsevier Ltd. All rights reserved.
The purpose of this paper is to point out that if there are some machines that do not process any job then the mathematical programming model provided by Eren [T. Eren, A note on minimizing maximum lateness in an m-ma...
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The purpose of this paper is to point out that if there are some machines that do not process any job then the mathematical programming model provided by Eren [T. Eren, A note on minimizing maximum lateness in an m-machine scheduling problem with a learning effect, Applied Mathematics and Computation 209 (2009) 186-190] may not be a valid one. A simple way to fix this problem is given. Furthermore, based on the idea of Eren's model, a general mathematical programming model is proposed. (C) 2010 Elsevier Inc. All rights reserved.
We revisit the assembly block storage location assignment problem (ABSLAP) at a shipyard, in order to compensate for the deficiency in performance verification of the heuristic ABSLAP algorithm developed by the previo...
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We revisit the assembly block storage location assignment problem (ABSLAP) at a shipyard, in order to compensate for the deficiency in performance verification of the heuristic ABSLAP algorithm developed by the previous study. In this article, we formulate a mathematical programming model of the ABSLAP, refine elaborately the heuristic ABSLAP algorithm and show the performance of the developed mathematical programming model and the revised heuristic ABSLAP algorithm. In addition, we explain simulation experiments conducted using the revised heuristic ABSLAP algorithm to investigate the influences of block stockyard layouts and production schedule instability on the block stockyard operations.
In studies oil scheduling problems, generally setup times and removal times of jobs have been neglected or by including those into processing times. However, in some production systems, setup times and removal times a...
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In studies oil scheduling problems, generally setup times and removal times of jobs have been neglected or by including those into processing times. However, in some production systems, setup times and removal times are very important such that they should be considered independent from processing times. Since, in general jobs are done according to automatic machine processes in production Systems processing times do not differ according to process sequence. But, since human factor becomes influential when setup times and removal times are taken into consideration, setup times will be decreasing by repeating setup processes frequently. This fact is defined with learning effect in scheduling literature. In this study, a bicriteria m-identical parallel machines scheduling problem with a learning effect of setup times and removal times is considered. The objective function of the problem is minimization of the weighted sum of total completion time and total tardiness. A mathematical programming model is developed for the problem which belongs to NP-hard class. Results of computational tests show that the proposed model is effective in solving problems with Lip to 15 jobs and five machines. We also proposed three heuristic approaches for solving large jobs problems. According to the best of our knowledge, no work exists oil the minimization of the weighted sum of total completion time and total tardiness with a learning effect of setup times and removal times. (C) 2008 Elsevier Inc. All rights reserved.
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