The locomotive scheduling problem (or the locomotive assignment problem) is to assign a consist (a set of locomotives) to each train in a pre-planned train schedule so as to provide them sufficient power to pull them from their origins to their destinations. Locomotive scheduling problems are among the most important problems in railroad scheduling. In this paper, we report the results of a stu...

Intention– Cyclic locomotive assignment planning is a specific type of organization of locomotive usage, and in fact, it means putting the complete workload to a closed chain, which is repeated periodically. The concept of cyclic locomotive assignment planning type organization in the area of train traction has proven in practice as the best one, but as it is made for in-advance defined timetab...

one of methods of improvement of the material flow is cross docking that in is considered as a good method to reduce inventory and improve customer satisfaction. too, the vehicle routing problem is one of the important problems in distribution management and its goal is to find paths for delivering various cargos. therefore, this study was conducted in order to vehicle routing problem with cros...

One of the important aspects of distribution optimization problems is simultaneously, controlling the inventory while devising the best vehicle routing, which is a famous problem, called inventory-routing problem (IRP). When the lot-sizing decisions are jointed with IRP, the problem will get more complicated called production inventory-routing problem (PIRP). To become closer to the real life p...

Transportation in economic systems such as services, production and distribution enjoys a special and important position and provides a significant portion of the country's gross domestic product. Improvements in transportation system mean improvements in the traveling routes and the elimination of unnecessary distances in any system. The Vehicle Routing Problem (VRP) is one of the practical co...

In recent years, great efforts have been made to reduce greenhouse gas emissions by vehicles. Petroleum products produces greenhouse gas emissions, therefore reducing the use of these products can make a major contribution to reducing pollution. The Fleet Size and Mix Vehicle Routing Problem is one of the most widely used routing branches. In this problem, there are vehicle with different capac...

this research presents and solves a new mathematical model for school bus routing problem (sbrp). sbrp is a specific case of vehicle routing problem (vrp). despite prevalent models, this model includes location and routing simultaneously. besides, the vehicles are non-homogenous. in addition, instead of locating schools which are the depots, we consider locating bus stops that are mentioned &ap...

mobile ad hoc networks (manets) are composed of mobile stations communicating through wireless links, without any fixed backbone support. in these networks, limited power energy supply, and frequent topology changes caused by node mobility, makes their routing a challenging problem. tora is one of the routing protocols that successfully copes with the nodes’ mobility side effects, but it doesn’...

A vehicle routing problem is a significant problem that has attracted great attention from researchers in recent years. The main objectives of the vehicle routing problem are to minimize the traveled distance, total traveling time, number of vehicles and cost function of transportation. Reducing these variables leads to decreasing the total cost and increasing the driver's satisfaction level. O...