Resource Management Of Liner Companies Under Uncertain Environment

With the development of economics globalization, world trade and in particular sea-borne trade has grown rapidly in the past decades. Maritime transportation provides a cheap mode for freight movement over long distance. Containerization has revolutionized the maritime industry. It has greatly boosted the trade and improved the efficiency of transportation and handling of cargos. With the increasing intensity of competitive market, the optimization of liner companies'resources management has become a hotspot that has attracted great attention from the managers and the researchers. This dissertation addresses the resource management of liner companies and aims at improving the system efficiency under uncertaint environment. On one hand is to reduce empty container management cost; on the other hand is to increase utilization of the slots in cooperation with logistics forwarder.The main contents and results in this dissertation are as follows:In chapter 2, we analyzed qualitatively the empty container management system of liner companies. The container transfer process, the disadvantages and causes of empty container reposition were analyzed. To solve this problem from a management point of view, we summerized a number of strategies and tactical policies, including both the cooperation among industry members and optimizing the enterprise management, proposed the guidance to reduce empty container reposition.In chapter 3, beginning with the analysis of uncertainties in empty container reposition system, we studied the empty container reposition of liner companies with uncertain net demand. Based on a budget of uncertainty, the formulation of reposition plan is divided into two phases:reposition and recourse action. We developed a two-stage robust optimization model with the objective of minimizing the total reposition cost and recourse cost. Iterative algorithm was proposed based on the analysis of solution properties. The simulation results showed that the two-stage robust model has strong anti-perturbation ability under uncertainty; while in the different amplitude of the perturbation, the reasonable selection of conservative level is also important to improve the robust performance.In chapter 4, considering the transformation between the empty container flow and the loaded container flow during the transfer process, we studied the reposition of empty containers under uncertain loaded container flow. Aiming at minimizing costs, nominal model was established to determine how many containers to be transported, leased and stored in each port. Then in accordance with the characteristics of this problem, the level of conservatism assoiated with ports and time was defined, and the corresponding robust optimization model was established. Then it was linearized based on the duality theory. At the same time, two upper bounds of violating customer satisfaction constraint were given and proved. The results showed that the upper bound dependent on the random variables and robust solutions is much tighter than that ratio only dependent on the random variables. At the same time, robust optimization methods effectively resist the impact of uncertainty to customers at low price.In chapter 5, we studied the cooperative and competitive relations between the liner company and logistics forwarder aiming at the important resource—slot. From the time perspective, this issue was divided into two aspects:one is the issue of long-term pre-sell of slot. Considering the stochastic demand, the unsold risk cost and the slot capacity constraint, stackelberg game model was established and game equilibrium solution was obtained to decide the price of the liner companies and order quantity of logistics forwarder. Through numerical experiments, an effective method was got to coordinate the system and double marginalization effect was reduced. The other is the issue of short-term slot sell. On the basis of the liner companies setting the price of slot and the logistics forwarder setting the price of service, the logistics forwarder decides to make extra efforts to attract more customers. Non-cooperative game model and Pareto cooperation model were established. Through analyzing risk aversion, bargaining ability and system utility function, cooperation profit distribution model was obtained. System analysis showed that the effective Pareto cooperation between both parties can increase the profit of each party and the entire system. Meanwhile, the slot is positively related to the importance of extra efforts under deterministic cost.