Keshavarz E.,Islamic Azad University at Sirjan
Journal of Intelligent and Fuzzy Systems | Year: 2016
In this paper, a new vertex-coloring problem of a fuzzy graph with crisp vertices and fuzzy edges is studied. Membership degree of a fuzzy edge is interpreted as incompatibility degree of its associated incident vertices. This interpretation can be used to define the concept of total incompatibility. Here, unlike the traditional graph coloring problems, two adjacent vertices can receive same colors; these type of vertices and their associated edge are named incompatible vertices and incompatible edge, respectively. In proposed coloring methodology, the total incompatibility of a vertex-coloring is defined as the sum of incompatibility degrees of all incompatible edges. Then, based on the minimum possible degree of total incompatibilities, fuzzy chromatic number of a fuzzy graph is introduced. In order to find an optimal k-coloring, with minimum degree of total incompatibly, firstly a binary programming problem is formulated. Then, a hybrid local search genetic algorithm is designed to solve the large-size problems. Practical uses of the proposed algorithm are illustrated and analyzed by different-size problems. Finally, a cell site assignment problem, as a real world application of the presented fuzzy graph vertex-coloring, is formulated and solved. © 2016 - IOS Press and the authors. All rights reserved.
Keshavarz E.,Islamic Azad University at Sirjan |
Khorram E.,Amirkabir University of Technology
Computers and Industrial Engineering | Year: 2011
In this paper, a fuzzy bi-criteria transportation problem is studied. Here, the model concentrates on two criteria: total delivery time and total profit of transportation. The delivery times on links are fuzzy intervals with increasing linear membership functions, whereas the total delivery time on the network is a fuzzy interval with a decreasing linear membership function. On the other hand, the transporting profits on links are fuzzy intervals with decreasing linear membership functions and the total profit of transportation is a fuzzy number with an increasing linear membership function. Supplies and demands are deterministic numbers. A nonlinear programming model considers the problem using the max-min criterion suggested by Bellman and Zadeh. We show that the problem can be simplified into two bi-level programming problems, which are solved very conveniently. A proposed efficient algorithm based on parametric linear programming solves the bi-level problems. To explain the algorithm two illustrative examples are provided, systematically. © 2011 Elsevier Ltd. All rights reserved.
Zounemat-Kermani M.,Shahid Bahonar University of Kerman |
Ghiasi-Tarzi O.,Islamic Azad University at Sirjan
European Journal of Environmental and Civil Engineering | Year: 2016
This article attempts to solve shallow water equations based on the natural element method (NEM). The foundation of the NEM method is based on the natural neighbour interpolation, and, in this article, the Sibson interpolation is used. Moreover, the nodal integration is applied for discretising the governing equations. The proposed method is validated by three 2D shallow water test cases, including (1) supercritical flow in converged channel, (2) subcritical flow in sudden expansion and (3) inflow jet into the main channel, and then compared with the experimental data. In addition, in order to evaluate the obtained results, the outcomes of the models are compared with the results of the conventional finite volume method (FVM). The results are evaluated by NRMSE and relative error criteria. In general, results indicate that the proposed NEM method is slightly superior to the FVM. © 2016 Taylor & Francis
Keshavarz E.,Islamic Azad University at Sirjan
Computers and Industrial Engineering | Year: 2016
Keshavarz and Khorram formulated a fuzzy bi-criteria transportation problem with fuzzy delivery time and fuzzy profit of transportation, as two conflicting objectives (Keshavarz & Khorram, 2011). They used the max-min criterion of Bellman and Zadeh to reformulate the presented fuzzy bi-criteria transportation problem as a single objective non-linear programming problem, then showed that the optimal solution of this non-linear programming can be found by solving a bi-level programming problem. Finally, they proposed an algorithm based on the parametric linear programming for solving this bi-level problem. In this paper, a shortcoming of Keshavarz and Khorram's algorithm is pointed out and a revised algorithm is proposed to solve the problem. In order to illustrate the performance of this algorithm, Keshavarz and Khorram's example is used and its optimal solution is improved. © 2016 Elsevier Ltd.
Hafezi A.,Islamic Azad University at Sirjan
Advances in Environmental Biology | Year: 2014
Collaboration works as a balancing tool which has the government on one side and public on the other side, and this balance axis is the idea of collaboration which is the defining element in public and government relations. The idea of collaboration is present in all aspects as a result of its autochthonous nature, although it has not been able to be presented potentially due to lack of management and authentic planning. Nowadays, with regards to withdrawal of government from developments framework, public's role as an effective element in reaching development, especially a sustainable one is an inevitable fact. A society can be developed only if, publics collaboration contexts as social capital and also the elites of the society as the leaders of this movement, are effective and active in all social, economic and cultural aspects. With this point of view, the purpose of publics collaboration in society, in addition to lowering the states ethnic and materialistic expenses, can act as a catalyzer and facilitate the process of obtaining the desired society. Also it must be noted that obtaining such a purpose, requires contexts that can in addition to developing a sense of dependence among public, create mutual trust between public and the state. Among these contexts instruction, informing, absorbing local elites and correction of patterns can be named, which can accomplish an axial and guiding role and also making laws from lower to higher levels on the basis of situation recognition and quantities. © 2014 AENSI Publisher All rights reserved.