Mina Riahee; Mostafa Zandieh
Abstract
Recovering, recycling, and remanufacturing end-of-life products (disassembly line) are appropriate methods of reducing the environmental impact associated with wastes. A disassembly line is a viable option for doing so. The objective of the disassembly line balancing problem (DLBP) is to coordinate disassembly ...
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Recovering, recycling, and remanufacturing end-of-life products (disassembly line) are appropriate methods of reducing the environmental impact associated with wastes. A disassembly line is a viable option for doing so. The objective of the disassembly line balancing problem (DLBP) is to coordinate disassembly line activities so that total operating times of workstations are nearly equal. The disassembly process mainly aims to reuse components in end-of-life products and thus reduce adverse environmental effects. This paper employs an approach based on the Kano model, Fuzzy AHP, M-TOPSIS, and PROMETHEE. Furthermore, using AND/OR precedence relationships, the optimal sequence of disassembly is obtained. Tasks are assigned to workstations according to priority and precedence relationships. An illustrative example of the proposed method is solved using both M-TOPSIS and PROMETHEE. Both methods lead to a decrease of two seconds in total cycle time. Despite yielding equal results, PROMETHEE is superior to M-TOPSIS in terms of complexity and ease of use. However, it takes longer to complete.
Mostafa Ebrahimpour Azbari; Mohsen Akbari; Fatemeh Rafiei Rashtababdi
Abstract
Today, organizations in an environment with growing changes, should be flexible enough to manage unpredictable threats and opportunities in an uncertain future and lead to better performance. Also, they should optimize their business processes to achieve operational efficiency. Besides, Operational absorptive ...
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Today, organizations in an environment with growing changes, should be flexible enough to manage unpredictable threats and opportunities in an uncertain future and lead to better performance. Also, they should optimize their business processes to achieve operational efficiency. Besides, Operational absorptive Capacity is a significant learning capabilities that may explain why some companies are enable to create a more effective response to environmental uncertainties. In this study, the impact of environmental uncertainty mediated by manufacturing flexibility and operational efficiency and moderating role of operational absorptive capacity on the performance of manufacturing firms has been tested. Also, the effect of manufacturing flexibility on the operational efficiency has been tested. A questionnaire is used as an instrument to collect data that is provided by experts and managers of 101 manufacturing companies in Rasht province. For the data analysis, structural equation modeling techniques (SEM) with the approach of Partial Least Squares (PLS) has been used. The results show that the company's performance can be improved by increasing manufacturing flexibility and operational efficiency . Also, with increasing flexibility, can provide more effective responses to environmental changes. The results confirmed the effect of manufacturing flexibility on the operational efficiency, as well as moderating role of operational absorptive capacity
Mohammad Mohammadi; Kamran Forghani
Abstract
The cell formation problem and the group layout problem, both are two important problems in designing a cellular manufacturing system. The cell formation problem is consist of grouping parts into part families and machines into production cells. In addition, the group layout problem is to find the arrangement ...
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The cell formation problem and the group layout problem, both are two important problems in designing a cellular manufacturing system. The cell formation problem is consist of grouping parts into part families and machines into production cells. In addition, the group layout problem is to find the arrangement of machines within the cells as well as the layout of cells.In this paper, an integrated approach is presented to solve the cell formation, group layout and routing problems. By Considering the dimension of machines, the width of the aisles, and the maximum permissible length of the plant site, a new framework, called spiral layout, is suggested for the layout of cellular manufacturing systems. To extend the applicability of the problem, parameters such as part demands, operation sequences, processing times and machine capacities are considered in the problem formulation. The problem is formulated as a bi-objective integer programming model, in which the first objective is to minimize the total material handling cost and the second one is to maximize the total similarity between machines. As the problem is NP-hard, three metaheuristic algorithms, based on Genetic Algorithm and Simulated Annealing are proposed to solve it. To enhance the performance of the algorithms, a Dynamic Programming algorithm is embedded within them. The performance of the algorithms is evaluated by solving numerical examples from the related literature. Finally, a comparison is carried out between the proposed spiral layout and the linear multi-row layout which has recently presented in the literature
Farzaneh Adabi; Javad Behnamian
Abstract
The production routing problem (PRP) integrates vehicle routing and production planning problems. Generally, in PRPs, the impact of competitors has not been considered. Clearly, in the real world, it is no longer possible to have a monopoly market. In competitive environment, customers choose a supplier ...
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The production routing problem (PRP) integrates vehicle routing and production planning problems. Generally, in PRPs, the impact of competitors has not been considered. Clearly, in the real world, it is no longer possible to have a monopoly market. In competitive environment, customers choose a supplier based on price and quality. So in this article as a definition of quality, providing quick access to customer needs and availability are determined as the requirements of a competitive environment. Therefore, the production routing problem has been modeled with knowing the earliest and latest time of competitor demand meeting. In this way, In case of delay in supplying customers demand, the market share is lost relative to the amount of delay. The problem is modeled and it has been solved by the GAMS software. Since particle swarm optimization has been successfully applied to a variety of problems, here, to solve the problem for the large-sized instances a particle swarm optimization algorithm is also presented. To evaluate the performance of the proposed algorithm, the results with small-sized instances were compared with solutions of GAMS.
Hossein Safari; Aliyeh Kazemi; Ahmad Mehrpoor Layeghi
Abstract
One of the most known subjects in management literature is performance assessment. In this paper, we have tried to provide a hybrid model in order to evaluate the performance of Iranian gas Transmission Company's operational zones. After an initial screening, due to the low number of Decision making ...
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One of the most known subjects in management literature is performance assessment. In this paper, we have tried to provide a hybrid model in order to evaluate the performance of Iranian gas Transmission Company's operational zones. After an initial screening, due to the low number of Decision making units, different combination of two input and one output are defined. 6 inputs and 4 output criteria have been chosen in initial screening. Based on the experts' judgments, weights or importance of different combinations of input and output extracted using SWARA technique. Then, based on the 22 different combinations, we calculated operational zones efficiency using DEA in the form of CCR and BCC models. In fact for each combination of two input and one output, efficiency for each operational zone has been calculated. Finally, there has been a decision matrix which its’ criteria were equal to different combinations of input and output criteria and their weights gained by SWARA and scores within the matrix were equal to taken efficiency from DEA. In order to calculate final efficiency and prioritizing each operational zone WASPAS technique is used. We use Cohen's kappa coefficient in order to prioritizing validation. The results show that zones 10, 7 and 6 with the highest efficiencies can be appropriate pattern for other zones in resource saving
Mehdi Seifbarghy; Shima Zangeneh
Abstract
In the classic models of facility location, it is assumed that the selected facilities always work based on the schedule while, in the real world, facilities are always exposed to disruption risk and sometimes these disruptions have long-term effects on the supply chain network and cause a lot of problems. ...
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In the classic models of facility location, it is assumed that the selected facilities always work based on the schedule while, in the real world, facilities are always exposed to disruption risk and sometimes these disruptions have long-term effects on the supply chain network and cause a lot of problems. In this paper, a mixed integer programing (MIP) model presented in order to determine how to serve the customers at the time of disruption in distribution centers in a two-echelon supply chain, including distribution centers and customers. This model selects potential places that minimize traditionally supply chain costs and also the transportation cost after distribution centers disruptions. In fact, the model tries to choose the distribution centers facilities with lowest cost and highest reliability and also allocate them to customers. The problem divided into two sub-problems using Lagrangian relaxation approach. By examining sub-problems optimal conditions, a heuristic solution is used for the first sub-problem and a genetic algorithm is used for the second sub-problem to solve large-scale problems. Finally, numerical examples are presented to examine the performance and efficiency of the proposed model and approach
Siamak Kheybari; Mostafa Kazemi
Abstract
TOPSIS is located in compensatory decision-making methods. The basic principle is that the chosen alternative should have the shortest distance from the positive ideal solution and the longest distance from the negative ideal solution. The existence of incremental and decreasing uniform trend in positive ...
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TOPSIS is located in compensatory decision-making methods. The basic principle is that the chosen alternative should have the shortest distance from the positive ideal solution and the longest distance from the negative ideal solution. The existence of incremental and decreasing uniform trend in positive and negative criteria is one of the TOPSIS characteristics in determining positive and negative ideal points. While the utility assigned to the decision maker after a certain level in each criterion will be less tangible. Therefore, in the ranking of alternatives in addition to the value of each alternative in each indicator, the balance among criteria of each alternative should be considered so the alternative that has an appropriate place in an important indicator, but does not have an appropriate place in other criteria, not to be the first chance for selecting. For this purpose, in this paper by adding virtual dimension to the decision matrix that comes from the deviations among criteria of each alternative, we have tried to compensate the mentioned weakness. To evaluate the proposed method, three different examples are presented. Thus, each of the three provided examples, solved by proposed method, TOPSIS, VIKOR, Deng and SAW and then by using the Spearman correlation coefficient the number of significant correlation relationships between the proposed method and TOPSIS with the other three methods were compared. Then, the rating similarity percentage of the proposed method and TOPSIS were compared with VIKOR, Deng and SAW.
