Optimization and reduction of costs in management of distribution and transportation of commodity are one of the main goals of many organizations. Using suitable models in supply chain in order to increase efficiency and appropriate location for support centers in logistical networks is highly important for planners and managers. Graph modeling can be used to analyze these problems and many oth...

Long-distance telephone companies in the United States (U.S.) pay access fees to local telephone companies to transport calls that originate and terminate on their networks. These charges form the largest portion of the cost of providing long-distance service. Recent changes in the structure of access rates, which were mandated by the Federal Communications Commission (FCC), have created opport...