Simulation & Optimization Researched And Applied In Port Container Logistics System

Port container logistics system consists of containers, ships, handling equipment, communication equipment, berths, container yards and human resource, etc. Since ports offer least gaps and maximal increment as logistics ' nodes, they are playing more important role in transportation. With the rapid development of container transportation in recent years, container terminals have to uplift themselves to meet more hard challenges. It is indispensable for ports to enhance their operation efficiency with reasonable planning. So it is very significant to make researches on port container logistics system.According to features of port container logistics system, this dissertation researched simulation and optimization of the system as follows.In the first chapter, research situations about port container logistics system, which have relations with simulation, optimization, simulation optimization and simulation modeling, were summarized. Central contents of and the framework of the dissertation were both introduced.There were no enough descriptions about dynamic behaviors of the port logistics system in recent studies. In allusion to the problem, chapter two analyzed operations in container terminals. An improved Object-oriented Petri Net (OPN) method was used for building a model of a container loading/unloading system. Object classes in the system were separated. Their attributes and methods were introduced. The static model and the Object Communication Net (OCN) of objects were built.Based on chapter two, chapter three built a basic OPN model of the loading/unloading system, then analyzed its performance by invariant method, such as deadlock, boundary and conservation. Afterwards, conflictions in the OPN model were researched and solved. Finally, considering control strategies, simulation verified that the OPN model was correct.In chapter four, two simulation examples were introduced. The first example studied a technique of transforming an OPN model into an eM-Plantmodel, which was used to simulate a real container terminal. Compared with history data, simulation verified further the OPN model was correct. The second example used optimized production technology (OPT) and simulation optimization, analyzed production bottleneck of the optimized scheme in chapter six, and gained a reasonable layout of the wharf surface.Chapter five advanced a simulation modeling method based on numeric electro circuit and discrete feature of a container logistics system. It analyzed logic relations among working procedures in a container unloading system. A simulation model of the system was built for researching on the effect of the method. Finally, it put forward a theory of simulating the behavior of a system by numeric electro circuit and hardware designed language.The planning and designing of a container terminal involves many factors, such as technology, economy and society, etc. On the other hand, loading/unloading operation is a discrete, random and dynamic process. So it makes difficult to plan a container terminal and to allocate its equipment. The development of port container transportation needs new design ideas and means, for meeting clients' demands and ensuring port's benefit. So chapter six built a multi-objective optimization model for reducing total cost and increasing average utilizations of berths and quay cranes, according as layout planning of wharf surface was affected by random factors in port operations. Simulation, artificial neural network and genetic algorithm were combined for solving the problem and key techniques were discussed. An optimized scheme was got when planning a container terminal.Chapter seven studied the problem of berth allocation, because reasonable resources allocation is an important way to enhance loading/unloading efficiency. A simulation optimization model was built for reducing the total delay time of ships. It reflected real container operations and considered the scheduling of quay cranes. How to solve it also was introduced. Finally, the method was used to solve a real berth allocation question. Chapter eight concluded the dissertation and looked forward to the future.