The Research Of Ocean Empty Container Allocation Optimization Model

The container is an advanced and normative way of transportation. It has made a great contribution to the development of world economy since its naissance. At the same time, the development of economy has greatly promoted the development of container transportation especially ocean container transportation. Up to now, as the global shipping market has already become saturated, shipping capacities supply exceeds demand and competition grows more and more vehement. Many shipping companies have to turn their chief targets to cost management one after another in the face of ceaseless decrease of profit and income. The imbalance of economy's development results in the unbalance of trade flow that caused serious imbalance between the supply and demand of empty container. So, there are a great deal of empty containers have to be allocated and disposed which account for 20 percent of the whole containers in transportation per year. In the various operating costs of a shipping company, container management cost has become the second largest cost only inferior to the cost of ports fee. At the same time, empty container allocation cost and container leasing cost which are highly related to the empty container allocation account for more than half of the container management cost. As a result, it's very central for every shipping company to organize the flow of empty container effectively and raise the efficiency of empty container allocation.The main research contents of this thesis are the optimization of ocean empty container allocation. By regarding one certain shipping company as the object of study, on the basis of analyzing the main characters and influence factors of empty container allocation system, this thesis established some optimization models and found some helpful quantitative decision methods for shipping company.Firstly, on the basis of analyzing the subjective and objective factors that caused empty container allocation, the thesis summarized the characteristics of ocean empty container allocation. Then, some valuable comprehensive proposals and measures that can improve the management of ocean empty container allocation are presented.Secondly, the main characters and influence elements which are necessary and crucial for the establishment of mathematic optimization model are analyzed.Finally, one simple basic optimization model based on two vessels, two ports and one nonstop shipping route is first established. The model is followed by one numerical example with a series of digital simulation analysis. The effects on decision of empty container's reposition and lease those are caused by various changes of cost factors and vessel carrying capacity in empty container allocation system are presented. Then, by complicating the basic model, one extended optimization model based on complex operating network that includes multi-ports, multi-vessels and multi-routes is established. Also it is followed by one numerical example based on actual operation.During the establishing of optimization model, stochastic factors including stochastic supply and demand of empty container are considered. By solving the stochastic variables with chance-constrained programming, stochastic programming model grounded on integer programming are established. At the same time, by explaining practical operating of empty container, the relationships among empty container supply, empty container demand and quantity of loaded container are anatomized, and therefore the static vessel carrying capacity in former models is changed into dynamic stochastic constrains. Moreover, in order to precisely express the direction of container flow in complex network, 'berth coefficient' is introduced. It can confirm one certain container flow exclusively by four parameters such as vessel, time, start port and destination port.This thesis follows the principle: more suitable to the fact. By completely analyzing the whole empty container allocation system, it successfully solved the classical optimization problem in empty container allocation with qualitative and quantitive analysis: from where, when and how many empty containers should be disposed to another port, and at where, when, how many containers should be leased. The target of this thesis' optimization models is to achieve minimum cost and maximum consigner's satisfaction simultaneously.