We address the one-to-one multi-commodity pickup and delivery traveling salesman problem (m-PDTSP) which is a generalization of the TSP and arises in several transportation and logistics applications. The objective is to find a minimum-cost directed Hamiltonian path which starts and ends at given depot nodes and such that the demand of each given commodity is transported from the associated sou...

With the growing demand for air transportation and the limited ability to increase capacity at key points in the air transportation system, there are concerns that, in the future, the system will not scale to meet demand. This situation will result in the generation and the propagation of delays throughout the system, impacting passengers’ quality of travel and more broadly the economy. There i...

The capacitated arc routing problem (CARP) is one of the most important routing problems with many applications in real world situations. In some real applications such as urban waste collection and etc., decision makers have to consider more than one objective and investigate the problem under uncertain situations where required edges have demand for more than one type of commodity. So, in thi...

Stochastics affects the optimal design of a network. This paper examines the single-source single-commodity stochastic network design problem. We characterize the optimal designs under demand uncertainty and compare with the deterministic counterparts to outline the basic structural differences. We do this partly as a basis for developing better algorithms than are available today, partly to si...

This report documents the development of several transportation optimization models under uncertainty. First, a robust evacuation transportation planning model for freeway traffic systems was developed, in which demand is uncertain. The study results provide preliminary evidence that routing traffic using such a robust, optimization-based model can improve the average objective performance. Nex...

One of the core concepts in transport and economic geography states that transportation is a derived demand, both for passengers and freight transport alike. This assumption is reflected in the conventional literature which underlines that transport exists because it is the expression of a spatially differentiated function of supply and demand and is thus considered to be “derived” from other a...

Solving traffic equilibrium problem, or “traffic assignment”, as the last step in Transportation Planning, distributes OD trip demands of a transportation network over the network links with regard to Traffic Equilibrium Law, and estimates the link flows. In formulations of traffic equilibrium which are based on path saving, the memory consumption is considerably affected by the number of effct...

Deciding shipment size is important in freight transport: it depends on the logistical imperatives of shippers and the technical possibilities of carriers. Shipment size choice is also closely related to transportation mode; it is therefore important from a public policy perspective. The theory of optimal shipment size and mode choice is robust. There are many inventory-theoretical models of op...

Data centers in the Bcloud[ will need to support a wide range of applications, each with their own input/output (I/O) requirements. Some applications perform small and random I/O operations, whereas others demand high streaming bandwidth. In addition, in order to reduce costs, cloud data centers will contain thousands of commodity servers and network switches. Delivering high performance with u...

Supply chain management is taken into account as an inseparable component in satisfying customers' requirements. This paper deals with the distribution network design (DND) problem which is a critical issue in achieving supply chain accomplishments. A capable DND can guarantee the success of the entire network performance. However, there are many factors that can cause fluctuations in input dat...