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Showing 4 results for Distance
Jain, Lachhwani, Volume 2, Issue 1 (4-2010)
Abstract
We develop an algorithm for the solution of multiobjective linear plus fractional programming problem (MOL+FPP) when some of the constraints are homogeneous in nature. Using homogeneous constraints, first we construct a transformation matrix T which transforms the given problem into another MOL+FPP with fewer constraints. Then, a relationship between these two problems, ensuring that the solution of the original problem can be recovered from the solution of the transformed problem, is established. We repeat this process of transformation until all the homogeneous constraints are removed. Then, we discuss the multi objective programming part, for which fuzzy programming methodology is proposed which works for the minimization of perpendicular distances between two hyper planes (curves) at the optimal points of the objective functions. A suitable membership function is defined with the help of the supremum perpendicular distance. A compromised optimal solution is obtained as a result of the minimization of the The supremum perpendicular distance. The corresponding optimal solution to the original problem is obtained using the transformation matrix. Finally, an example is given to illustrate the proposed model.
M Aman, J Tayyebi, Volume 5, Issue 2 (10-2014)
Abstract
Given an instance of the minimum cost flow problem, a version of the corresponding inverse problem, called the capacity inverse problem, is to modify the upper and lower bounds on arc flows as little as possible so that a given feasible flow becomes optimal to the modified minimum cost flow problem. The modifications can be measured by different distances. In this article, we consider the capacity inverse problem under the bottleneck-type and the sum-type weighted Hamming distances. In the bottleneck-type case, the binary search technique is applied to present an algorithm for solving the problem in O(nm log n) time. In the sum-type case, it is shown that the inverse problem is strongly NP-hard even on bipartite networks
Davoud Bastehzadeh, Gholamreza Godarzi, Mehdi Sadeghi Shahdani, Saeid Mehrabian, Volume 14, Issue 2 (12-2023)
Abstract
The purpose of this article is to investigate the modes of vehicles based on the type and number of urban travel facilities for passengers. As you know, to divide transportation models based on goal programming, is to divide all transportation modes for urban station routes by type and region.The main objective of this is to present the best mode (vehicle) of transportation based on travel modeling in transportation areas of urban trips for multi-objective transportation goal programming. In this case, the type of transportation solution is determined in the desired area on the way to the stations, according to which the pollution reduction, travel time reduction, cost reduction, availability, maximum safety and comfort of the means of transportation are reduced, increased or liminated.
O. Keramatlou, Dr N. Javadian, H. Didehkhani, M. Amirkhan, Volume 14, Issue 2 (12-2023)
Abstract
In this paper, a closed-loop supply chain (CLSC) is modeled to obtain the best location of retailers and allocate them to other utilities. The structure of CLSC includes production centers, retailers’ centers, probabilistic customers, collection, and disposal centers. In this research, two strategies are considered to find the best location for retailers by focusing on 1) the type of expected movement and 2) expected coverage. To this end, a bi-objective nonlinear programming model is proposed. This model concurrently compares Strategies 1 and 2 to select the best competitor. Based on the chosen strategy, the best allocation is determined by employing two heuristic algorithms, and the locations of the best retailers are determined. As the proposed model is NP-hard, a meta-heuristics (non-dominated sorting genetic) algorithm is employed for the solution process. Afterward, the effectiveness of the proposed model is validated and confirmed, and the obtained results are analyzed. For this purpose, a numerical example is given and solved through the optimization software.
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