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trapezoidal-fuzzy-numbers
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Duality results and a dual simplex method for linear programming problems with trapezoidal fuzzy variables
, Article Fuzzy Sets and Systems ; Volume 158, Issue 17 , 2007 , Pages 1961-1978 ; 01650114 (ISSN) ; Nasseri, S. H ; Sharif University of Technology
2007
Abstract
Linear programming problems with trapezoidal fuzzy variables (FVLP) have recently attracted some interest. Some methods have been developed for solving these problems by introducing and solving certain auxiliary problems. Here, we apply a linear ranking function to order trapezoidal fuzzy numbers. Then, we establish the dual problem of the linear programming problem with trapezoidal fuzzy variables and hence deduce some duality results. In particular, we prove that the auxiliary problem is indeed the dual of the FVLP problem. Having established the dual problem, the results will then follow as natural extensions of duality results for linear programming problems with crisp data. Finally,...
Solving a Fuzzy Multi-objective Rransportation Problem Using Interactive Methods
, M.Sc. Thesis Sharif University of Technology ; Mahdavi Amiri, Nezamoddin (Supervisor)
Abstract
Decision making is the most important and popular aspect of applying mathematical methods in various fields of human activity. Decisions are nearly always made on the basis of information obtained in conditions of uncertainty. In this thesis, the transportation planning decision (TPD) problem is defined with fuzzy parameters. Our purpose is to simultaneously minimize the total production and transportation costs and the total delivery time with reference to budget constraints and available supply, machine capacities at each source, as well as forecast demand and warehouse space constraints at each destination, and achieve an expected efficient solution for the decision maker according to the...
A new mixed fuzzy-LP method for selecting the best supplier using fuzzy group decision making
, Article Neural Computing and Applications ; Volume 23, Issue SUPPL1 , 2013 , Pages 345-352 ; 09410643 (ISSN) ; Eslamipoor, R ; Nobari, A ; Sharif University of Technology
2013
Abstract
Even though there have been so many articles and studies that focused on the supplier selection problem, a few of them considered the major decisions related to supplier selection. In this paper, the supplier selection problem is studied under a novel fuzzy approach in multiple sourcing conditions to select appropriate supplier in group decision-making environment regarding multiple sources. The use of the model is suitable in evaluating situations that involve subjectivity, vagueness and imprecise information. The group data have been used in multiple criteria decision making with multiple objective supplier selection. Trapezoidal fuzzy numbers are applied to evaluate the weights of...
Fuzzy turnover rate chance constraints portfolio model
, Article European Journal of Operational Research ; Volume 228, Issue 1 , 2013 , Pages 141-147 ; 03772217 (ISSN) ; Abessi, M ; Modarres, M ; Sharif University of Technology
2013
Abstract
One concern of many investors is to own the assets which can be liquidated easily. Thus, in this paper, we incorporate portfolio liquidity in our proposed model. Liquidity is measured by an index called turnover rate. Since the return of an asset is uncertain, we present it as a trapezoidal fuzzy number and its turnover rate is measured by fuzzy credibility theory. The desired portfolio turnover rate is controlled through a fuzzy chance constraint. Furthermore, to manage the portfolios with asymmetric investment return, other than mean and variance, we also utilize the third central moment, the skewness of portfolio return. In fact, we propose a fuzzy portfolio mean-variance-skewness model...