In many applications, the network design problem (NDP) faces significant uncertainty in transportation costs and demand, as it can be difficult to estimate current (and future values) of these quantities. In this paper, we present a robust optimization-based formulation for the NDP under transportation cost and demand uncertainty. We show that solving an approximation to this robust formulation...

A number of factors influence the efficiency, productivity, and welfare of transportation networks. Travel demand, user costs, and facility supply costs equili-brate on various time scales under a set of pricing (taxes and tolls), investment and ownership policies. Two types of equilibria exist in a transportation network, short-run traffic equilibrium and long-run supply-demand equilibrium. Th...

today, along with enhancement of social well-being andeconomic development, demand for transportation is growing increasingly.many countries are seeking for providing transportation servicesat a reasonable price. therefore, optimization of carrying goods on nationalor international roads is highly important in terms of costs andtransportation indicator, so that the goods are shipped at minimumc...

In this paper the factors having influence on travel demand to Iran are paper explored. The hypothesis of the research specifies the variable of “domestic upheavals and insecurity” as the most significant obstacle to expansion of the demand for travel to Iran. To test the above hypothesis, first several demand models that have been proposed to study demand for tourism in different countries, ar...

In this paper, a parametric method is introduced to solve fuzzy transportation problem. Considering that parameters of transportation problem have uncertainties, this paper develops a generalized fuzzy transportation problem with fuzzy supply, demand and cost. For simplicity, these parameters are assumed to be fuzzy trapezoidal numbers. Based on possibility theory and consistent with decision-m...

in many practical distribution networks, managers face significant uncertainties in demand, local price of building facilities, transportation cost, and macro and microeconomic parameters. this paper addresses design of distribution networks in a supply chain system which optimizes the performance of distribution networks subject to required service level. this service level, which is considere...

The aim of Fuzzy transportation is to find the least transportation cost of some commodities through a capacitated network when the supply and demand of nodes and the capacity and cost of edges are represented as fuzzy numbers. Many previous papers [4, 5, 13, 14] have presented arithmetic operations, alpha level and simple ranking by operations. P. Pandian [7, 8] has presented some methods for ...

T availability of relatively cheap small jet aircrafts suggests a new air transportation business: dial-a-flight, an on-demand service in which travelers call a few days in advance to schedule transportation. A successful on-demand air transportation service requires an effective scheduling system to construct minimum-cost pilot and jet itineraries for a set of accepted transportation requests....

Supply chain network design in perishable product has become a challenging task due to its short life time, spoilage of product in degradation nature and stochastic market demand. This paper focused on designing and optimizing model for perishable product in stochastic demand, which comprises multiple levels from producer, local collector, wholesaler and retailers. The ultimate goal is to optim...