In this research, we develop an integrated scheduling model that combines passenger, cargo and combi flight scheduling. We employ network flow techniques to construct the model which is formulated as an integer multiple commodity network flow problem that is characterized as NP-hard. A family of heuristics, based on Lagrangian relaxation, a sub-gradient method, heuristics for the upper bound so...

Motivated by a problem in the commodity transportation, a mathematical model is developed to calculate capacity of single-commodity network when the time reliability levels of transporting commodity between origin-destination pairs are constrained. We use a hybrid intelligent algorithm, in which genetic algorithm is embedded with Monte Carlo simulation to solve the optimization model. In the hy...

We consider a scenario where the communication nodes in a sensor network have limited energy, and the objective is to maximize the aggregate bits transported from sources to respective destinations before network partition due to node deaths. This performance metric is novel, and captures the useful information that a network can provide over its lifetime. The optimization problem that results ...

We consider a fundamental problem, called QoS-aware Multicommodity Flow, for assessing robustness in transportation planning. It constitutes a natural generalization of the weighted multicommodity ow problem, where the demands and commodity values are elastic to the Quality-of-Service (QoS) characteristics of the underlying network. The problem is also fundamental in other domains beyond transp...

In this paper we define the multi-commodity connected facility location (MCFL) problem, a natural generalization of the well-known multi-commodity rent-or-buy (MROB) and connected facility location (CFL) network design problems. Like in MROB, we wish to send one unit of flow from a set of sources to a set of sinks. This flow is supported by renting or buying edges. For each bought edge e, we pa...

This paper presents an evolutionary algorithm for the network design problem in the liner shipping industry with focus on the fitness calculation. The main contribution of this work are several new business constraints, such as committed partner capacities using a maximum flow algorithm and the transit times using a shortest path evaluation. Beside the cargo flows, the transit times are importa...

Using MPLS for efficient traffic engineering crucially depends on the optimal dimensioning of Label Switched Paths (LSPs). The standard formulation as multi-commodity flow problem periodically solves a mixed integer programming problem that maximizes total network revenue, assuming fixed charges for carrying traffic of a certain QoS (Quality-of-Service). This paper generalizes this approach: ch...

We consider here a multicommodity flow network optimization problem with nonconvex but piecewise convex arc cost functions. We derive complete optimality conditions for local minima based on negative-cost cycles associated with each commodity. These conditions do not extend to the convex non-smooth case.

We consider the minimum cost multicommodity flow problem in dynamic networks with time-varying capacities of arcs and transit times on arcs that depend on the sort of commodity entering them. We assume that cost functions, defined on arcs, are nonlinear and depend on time and flow, and the demand function also depends on time. Moreover, we study the problem in the case when transit time functio...