In this article we present an algorithm for converting a network problem with several sources and several sinks including several transfer nodes and condition of supplying the demand of any sink from a particular source to the transportation problem.  Towards this end, and considering the very special structure of transportation algorithm, after implementing the shortest path algorithm or ...

Due to many damages that human activities have imposed on the environment, authorities, manufacturers, and industry owners have taken into account the development of supply chain more than ever. One of the most influential and essential human activities in the supply chain are transportation which green vehicles such as electric vehicles (EVs) are expected to generate higher economic and enviro...

In many logistic systems for less than truckload (LTL) shipments, transportation of goods from one origin to its destination is made through collection tours to a hub and delivery tours from the same or another hub, while the goods are shipped between two hubs using Full Truckload (FTL) shipments. Therefore, managers need to determine the location of the hubs, the allocation of non-hub nodes, a...

In this study, we discuss the capacitated facility location-allocation problem with uncertain parameters in which the uncertainty is characterized by given finite numbers of scenarios. In this model, the objective function minimizes the total expected costs of transportation and opening facilities subject to the robustness constraint. To tackle the problem efficiently and effectively, an effici...

This paper formulates a mathematical model for the Green Vehicle Routing Problem (GVRP), incorporating bi-fuel (natural gas and gasoline) pickup trucks in a mixed vehicle fleet. The objective is to minimize overall costs relating to service (earliness and tardiness), transportation (fixed, variable and fuel), and carbon emissions. To reflect a real-world situation, the study considers: (1) a co...

Determining the optimal layout of an intermodal terminal network, more specifically the optimal locations of the terminals, is a complicated matter that requires adequate decision support tools. In this paper, a bi-objective model is developed, minimizing both the transportation cost for the users of the terminal network, as well as the location cost for the terminal operators. A problem-specif...

We propose a maximal covering location problem for helicopter emergency medical service system. In the system, the transportation time of each patient to a hospital depends on both locations of helipads for helicopters to land and take off and hospitals for deploying helicopters. The aim of this paper is to provide an optimal location strategy of both the helipads and the hospitals so as to max...

Hubs are facilities used to treat and dispatch resources in a transportation network. The main idea of Hub Location Problems (HLP) is to locate a number of hubs in a network and route resources from origins to destinations such that the total cost of attending all demands is minimized. In this study, we investigate a particular HLP, called the Tree of Hubs Location Problem in which hubs are con...

an extended star is a tree which has only one vertex with degree larger than two. the -center problem in a graph  asks to find a subset  of the vertices of  of cardinality  such that the maximum weighted distances from  to all vertices is minimized. in this paper we consider the -center problem on the unweighted extended stars, and present some properties to find solution.

Evaluation and selection of concrete production facility location is an important strategic decision making problem for both public and private sector. The multi-dimensional, multi-criteria nature of the concrete production facility location problem limits the usefulness of any particular single objective model. In this study, social, economical, technological, environmental and transportation ...