— We treat a discrete uncapacitated facility location problem where the installation cost per facility is a gênerai nonlinear function of the number of established facilities. Assuming a convexity proper ty, Mirchandani and Jagannathan developed a heur is tic solution procedure for this problem. Hère, we show how to modify their algorithm in order to get and prove exact solutions and, at the sa...

in this paper we study finding the $(k,l)$-core problem on a tree which the vertices have positive or negative weights. let $t=(v,e)$ be a tree. the $(k,l)$-core of $t$ is a subtree with at most $k$ leaves and with a diameter of at most $l$ which the sum of the weighted distances from all vertices to this subtree is minimized. we show that, when the sum of the weights of vertices is negative, t...

competitive facility location focus on locating facilities by considering the fact of competition in businesses, so every facilities try to reach their reachable shares through competition. reachable shares have an indirect relation with the distance of facilities to the customer and a direct relation with the attractiveness of the facility. attractiveness of any facility is depend on variety o...

a facility location is said to be competitive when other facilities are present in the market and new facilities have to compete with these existing facilities for a market share. in other words, in a competitive facility location problem we do not see monopoly that exists in classic location models. in such a situation, existing facilities react to locate new facilities by adjusting their attr...

the decisions made in the planning phase of a building project greatly affect its future operation and maintenance (o&m;) cost. recognizing the o&m; cost of condominiums’ common facilities as a critical issue for home owners, this research aims to develop an artificial neural network (ann) o&m; cost prediction model to assist developers and architects in effectively assessing the impacts of the...

Network location models comprise one of the main categories of location models. These models have various applications in regional and urban planning as well as in transportation, distribution, and energy management. In a network location problem, nodes represent demand points and candidate locations to locate the facilities. If the links network is unchangeably determined, the problem will be ...

Facility location-network design (FLND) problem, which determines the location of facilities and also communication links between the demand and facility nodes, is arisen from the combination of the facility location and network design problems. This paper deals with fuzzy capacitated facility location-network design model which aims to select the facilities and candidate links in a way that yi...

the development of optimization and mathematical models for closed loop supply chain (clsc) design has attracted considerable interest over the past decades. however, the uncertainties that are inherent in the network design and the complex interactions among various uncertain parameters are challenging the capabilities of the developed tools. the aim of this paper, therefore, is to propose a n...

introduction: identifying training needs and implementing appropriate courses is one of the important steps to empower managers and experts specialists. this has the most important role in improving organizational performance. in this study, considering the importance of training programs effectiveness, the training needs of managers and experts and their relation to individual and institutiona...