Annals of Optimization Theory and PracticeAnnals of Optimization Theory and Practice
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Feed provided by Annals of Optimization Theory and Practice. Click to visit.Linear programming problem with generalized interval-valued fuzzy numbers
http://aotp.fabad-ihe.ac.ir/article_58381_6864.html
In this paper, we concentrate on linear programming problems in which the cost vector, the technological coefficients and the right-hand side values are interval-valued generalized trapezoidal fuzzy numbers. To the best of our knowledge, till now there is no method described in the literature to find the optimal solution of the linear programming problems with interval-valued generalized trapezoidal fuzzy numbers. We apply the signed distance for defuzzification of this problem. The crisp problem obtained after the defuzzification is solved by the linear programming methods. Finally, we give an illustrative example and its numerical solutions.Mon, 30 Apr 2018 19:30:00 +0100A Fuzzy multi-product two-stage supply chain network design with possibility of direct shipment
http://aotp.fabad-ihe.ac.ir/article_63490_6864.html
The configuration of the supply chain network (SCN) is one of the strategic issues that have a major impact on the overall performance of the supply chain. A well designed SCN leads to an ability to reduce the supply chain total cost. These purposes are influenced by the supply chain strategy, which is based either on direct or indirect supply or shipment. In the case of direct shipment, the products are directly transported from the point of origin to the customers. In the classic transportation problems, it is usually assumed that the transportation time and costs are certain. Most existing mathematical models neglect the presence of uncertainty within a programming environment. This uncertainty might come about because of traffic jam, machine malfunctioning, defect in raw material, interpretation of various events and etc. These emprise parameters can be considering as fuzzy numbers. In this study, for the first time a mathematical model for a responsive, multi-product two-stage, SCN with possibility of direct shipment is proposed. Because of the unpredictable factors that mentioned above, cost coefficients are considered as trapezoidal fuzzy numbers. Therefore, for validation, the proposed model is coded by GAMS software. The results showed that relevant model is valid.Mon, 30 Apr 2018 19:30:00 +0100Country risk assessment by applying multi-criteria decision-making methods: a case study to ...
http://aotp.fabad-ihe.ac.ir/article_65263_6864.html
The Middle East and North Africa (MENA) have been attracting many international investors for decades, but the current geopolitical situation has not shown a welcoming face towards foreign investors. Consequences of war, terror and political changes in the region have forced many international companies to reconsider their plans or withdraw their investments. On the other hand, there are companies that have faith in investing in the emerging market of the MENA with fewer competitors. It must be mentioned that narrowing down the best possible decision needs research on the current situation as well as analyzing and forecasting of the upcoming situations in terms of many factors within the country concerned and the region. The Multi-Criteria Decision Making (MCDM) analysis helps investors to choose the best alternative from a set of relevant criteria. In this paper, one of the well-known MCDM methods, TOPSIS, was used to rank twenty-three countries based on twenty key indicators within the years 2000-2015. The outcome of these findings provides a set of country rankings for an interested group of decision makers, policy makers, stakeholders, and other involved parties based on their interest in the MENA region in the so-called Arab Spring and post-Arab Spring environment.Mon, 30 Apr 2018 19:30:00 +0100Countries credit ranking: a simple weighted non-linear programming model
http://aotp.fabad-ihe.ac.ir/article_68822_0.html
In this study a non-linear weighted sum model is proposed to rank countries based on economic factors. This ranking problem could be new and useful as most of previous researches rated countries not rank them. The countries are ranked from the best to the worst one by their score obtained by the model from credit point of view. As an advantage of the model, it is solvable by an analytical solution method manually instead of using optimization software. The analytical solution is useful for managers and decision makers to apply the model easily. The obtained ranking is compared with Moody’s rating to discuss the efficiency of the model.Sun, 29 Jul 2018 19:30:00 +0100Refueling station location problem under uncertain environment
http://aotp.fabad-ihe.ac.ir/article_65264_6864.html
Development of the infrastructure of alternative fuel stations is one of the best ways to extend the use of alternative fuel vehicles. Hence, constructing refueling stations with minimum cost is an important issue. On the other hand, considering the exact value of cost is not match with real cases. In this regard, the cost of building station is considered as a trapezoidal fuzzy value and a mathematical fuzzy programming model is presented in this paper. In order to solve the fuzzy model, first the model is converted to an interval programming model, then the equivalent bi-objective crisp model of the interval programming problem is written. Finally, two interactive fuzzy solution approaches are used to solve the respective bi-objective crisp model. The results show that the performance of the solution approaches is the same.Mon, 30 Apr 2018 19:30:00 +0100