this paper addresses a reliable facility location problem with considering facility capacity constraints. in reliable facility location problem some facilities may become unavailable from time to time. if a facility fails, its clients should refer to other facilities by paying the cost of retransfer to these facilities. hence, the fail of facilities leads to disruptions in facility location dec...

We conduct a comprehensive review on multi-level facility location problems which extend several classical facility location problems and can be regarded as a subclass within the well-established field of hierarchical facility location. We first present the main characteristics of these problems and discuss some similarities and differences with related areas. Based on the types of decisions in...

The following problem arose in connection with studies of Internet web page caching. The general setting is as follows: In some fixed metric space M , k “servers” S1, . . . , Sk are given with some arbitrary initial locations in M . Requests for service at certain points σ1, σ2, σ3, . . . , σN , in M arrive over time. Immediately after request σt is received, exactly one of several mutually exc...

1.2 Hardness of k-median Theorem 1. It is hard to approximate k-median within 1+ 2 e1/c for any c < 1. This theorem is equivalent to the 1− 1/e− hardness shown in [2] and follows from a standard reduction from set cover. The main idea is to take an approximation algorithm for k-median, and use it to obtain a partial set cover. Then repeat this process, again partially covering the remaining ite...

Facility location is a complex real-world problem which needs a strategic management decision. This paper provides a general review on studies, efforts and developments in Facility Location Problems which are classical optimization problems having a wide-spread applications in various areas such as transportation, distribution, production, supply chain decisions and telecommunication. Our goal ...

cellular manufacturing system (cms) is highly important in modern manufacturing methods. given the ever increasing market competition in terms of time and cost of manufacturing, we need models to decrease the cost and time of manufacturing. in this study, cms is considered in condition of dynamic demand in each period. the model is developed for facing dynamic demand that increases the cost of ...

a facility layout problem is concerned with determining the best position of departments, cells, or machines on the plant. an efficient layout contributes to the overall efficiency of operations. it’s been proved that, when system characteristics change, it can cause a significant increase in material handling cost. consequently, the efficiency of the current layout decreases or is lost and it ...