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...

it is necessary to consider the impact of demand uncertainty to model the comprehensive approach for supply chain network design. this paper presents four echelons, multiple commodity, and strategic–tactical model for designing supply chain network. uncertain demand, transportation mode selection with lead time configuration has been considered. a numerical example has been implemented to verif...

The analysis proceeds with a review of the problem of forecasting transportation requirements. Several idiosyncratic models are examined and their properties specified. The forecasting of transportation stocks and commodity flows is discussed. Models of the demand for transportation services are implemented with empirical data. Graph theory as an interpretative frame of reference is introduced ...

Network analysis is a usual approach to evaluate the performance of real-life systems such as transportation systems. We construct a multicommodity stochastic flow network with weighted capacity allocation to model the transportation systems. Each arc with cost attribute has several possible capacities. The capacity weight, the consumed quantity of arc capacity by per commodity, varies with the...

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...

The availability of relatively cheap small jet planes has lead to the creation of on-demand air transportation services in which travelers call a few days in advance to schedule a flight. 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. We present an intege...

This study presents a multimodal hub location problem which has the capability to split commodities by limited-capacity hubs and transportation systems, based on the assumption that demands are stochastic for multi-commodity network flows. In the real world cases, demands are random over the planning horizon and those which are partially fulfilled, are lost. Thus, the present study handles dema...

We now consider network flow problems. Such problems have some very nice properties. Specifically, we consider the minimum cost network flow problem, also known as the transshipment problem. In this problem, we are given a directed graph (V,E). The goal is to transport certain amounts of a single commodity from some vertices to others, across the edges of the graph. Specifically, each vertex v ...

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...