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 solvi...

Delay management is an important issue in the daily operations of any railway company. The task is to update the planned timetable to a disposition timetable in such a way that the inconvenience for the passengers is as small as possible. The two main decisions that have to be made in this respect are the wait-depart decisions to decide which connections should be maintained in case of delays a...

We consider the stochastic capacitated transshipment problem for freight transportation where an optimal location of the transshipment facilities, which minimizes the total cost, must be found. The total cost is given by the sum of the total fixed cost plus the expected minimum total flow cost, when the throughput costs of the facilities are random variables with unknown probability distributio...

establishing a network of transit routes with satisfactory demand coverage is one of the main goals of transitagencies in moving towards a sustainable urban development. a primary concern in obtaining such anetwork is reducing operational costs. this paper deals with the problem of minimizing construction costsin a grid transportation network while satisfying a certain level of demand coverage....

this paper proposes a new mathematical model for designing and planning postal parcels carriage and postal networks. the objective of postal network designing is to determine the location, size and connection between the postal stations in a city, province or country. in this paper, a kind of multiple locations-allocations hub problem with limited capacity in collecting, distributing and broadc...

In this paper, a fuzzy random minimum cost flow problem is presented. In this problem, cost parameters and decision variables are fuzzy random variables and fuzzy numbers respectively. The object of the problem is to find optimal flows of a capacitated network. Then, two algorithms are developed to solve the problem based on Er-expected value of fuzzy random variables and chance-constrained pro...

closed-loop supply chain network design is a critical issue due to its impact on both economic and environmental performances of the supply chain. in this paper, we address the problem of designing a multi-echelon, multi-product and capacitated closed-loop supply chain network. first, a mixed-integer linear programming formulation is developed to maximize the total profit. the main contribution...

mends the use of travel time values for congested periods that are 2.5 times the value of time estimates during uncongested periods (7). Kawamura investigated differences in value of time among operators and trucking industry segments; findings from Kawamura’s research show that freight carriers have a value of time that is several times higher than that of passenger vehicles and that there is ...