arXiv subjects

Jafar Fathali

Publications and source records attributed to Jafar Fathali.

4 recordsLinked to original sources

arXiv2025

Inverse single facility location problem in the plane with variable coordinates

In traditional facility location problems, a set of points is provided, and the objective is to determine the best location for a new facility based on criteria such as minimizing cost, time, and distances between clients and facilities. Conversely, inverse single facility location problems focus on adjusting the problem's parameters at minimal cost to make a specific point optimal. In this paper, we present an algorithm for the general case of the inverse single facility location problem with variable coordinates in a two-dimensional space. We outline the optimality conditions of this algorithm. Additionally, we examine the specific case namely the inverse minisum single facility location problem and test the algorithm on various instances. The results demonstrate the algorithm's effectiveness in these scenarios.

math.OC↗

arXiv2020

A row generation method for inverse continuous facility location problem

In a single facility location problem, a set of points is given and the goal is finding the optimal location of new facility respect to given criteria such as minimizing time, cost and distances between the clients and facilities. On the other side, the inverse models try to modify the parameters of the problem with the minimum cost such that a given point becomes optimal. In this paper, we introduce a novel algorithm for the general case of the inverse single facility location problem with variable weights in the plane. The convergence and optimality conditions of the algorithm are presented. Then in the special cases, the inverse minisum and minimax single facility location problems are considered and the algorithm tested on some instances. The results indicate the efficiency of the algorithm on these instances.

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arXiv2018

The balanced 2-median and 2-maxian problems on a tree

This paper deals with the facility location problems with balancing on allocation clients to servers. Two bi-objective models are considered, in which one objective is the traditional p-median or p-maxian objective and the second is to minimize the maximum demand volume allocated to any facility. An edge deletion method with time complexity O(n^2) is presented for the balanced $2$-median problem on a tree. For the balanced 2-maxian problem, it is shown the optimal solution is two end vertices of the diameter of the tree, which can be obtained in a linear time.

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arXiv2017

The stochastic queue core problem on a tree

In this paper, an stochastic queue core problem on a tree, which seeks to find a core in an M/G/1 operating environment is investigated. Let T = (V,E) be a tree, an stochastic queue core of T is assumed to be a path P, for which the summation of the weighted distances from all vertices to the path as well as the average response time on the path is minimized. Some general properties of the stochastic queue core problem on the tree are presented, while an algorithm with $max\{o(n^2l), o(n^2log^2(n))\}$ is provided to find the queue l-core on the tree.

math.OC↗