【作者】 李彦来；

【导师】 高自友；

【作者基本信息】 北京交通大学 ， 交通运输规划与管理， 2011， 博士

【摘要】 物流网络是物流活动的载体,是整个物流管理活动赖以存在和发挥效能的物质基础。无论从网络结构角度还是从系统内部相互作用关系看,物流网络都是-个复杂的大系统,其中有许多优化问题需要解决。因此,采用复杂系统及优化理论研究物流网络的结构特点及设计问题,可以更好地理解物流活动的运作规律,为解决物流管理问题提供新的视角,为进一步合理规划物流网络提供理论基础。本论文结合复杂网络的相关理论对物流网络的承载能力及价格演化特点进行了分析,采用博弈论的知识建立了服务定价及节点选址的双层规划模型,并对模糊条件下物流配送路径优化问题进行了探讨。本论文的主要内容有如下几个方面：(1)基于复杂网络理论,研究了不同结构特点物流网络的承载能力,分析了最优的网络拓扑结构。介绍了物流网络复杂性的研究方法。模拟了各类复杂网络在弹性需求条件承载能力与相关参数的关系,随着参数β的增大,即OD对间的费用估计越准确,系统产生的OD总需求量越小,并在最后达到平衡状态。同时得到系统总OD需求量与网络规模呈幂律关系,其指数受参数β的影响不大。更重要的是模拟结果显示网络规模越大,系统承载的平均OD需求量越小,这一现象为我们合理进行网络设计提供了科学依据。(2)研究了物流网络中价格演化特性。空问价格规律指的是如果供应价格加上运输费用小于需求价格,有交易产生,否则没有交易。本文首先以物流网络中空间价格规律为基础,研究了价格在不同网络结构中演化的基本特征。发现网络连接随机化程度越大,群落结构越明显,平均价格下降越快,系统将在较短时间达到平衡。对于无标度网络其规模越大,价格平均水平下降越慢。这主要是因为不同网络结构其平均最短距离不同,造成价格演化影响程度不同而形成的。同时考虑物流服务商和客户各自的竞争特点,应用博弈论和双层规划理论分析了物流服务的定价问题。并应用算例对模型和算法进行了验证,结果表明算法有很好的收敛性,其它相关参数对上下层目标函数值的影响程度不同。(3)建立了考虑流量均衡及信息共享条件下的物流设施选址模型。从节约社会资源的角度考虑,物流中心的修建要尽量使流量分布均衡,建立了考虑流量分布均匀的物流中心选址双层规划模型,并给出了一个简单的求解算法,算例分析表明该模型从理论上可以避免物流资源利用不充分的问题。同时建立了考虑信息共享条件下物流节点的选址问题,通过数值模拟得到随着信息共享程度的增加,系统总费用会有明显的降低,但随着共享水平的进一步增加,系统费用的变化会逐渐稳定。这说明信息共享水平将影响物流企业及客户的利益,合理的信息共享程度能同时提高双方的收益。(4)研究了模糊机会约束条件下物流配送路径优化问题。在前人研究的基础上,提出了基于模糊机会约束的物流配送路径优化模型,并给出了基于模糊模拟的遗传算法求解该问题,实验计算结果表明,采用模糊模拟技术可以方便地处理模糊机会约束条件下物流配送路径优化问题,为快速解决此类问题提供了一种新的尝试。更多还原

【Abstract】 Logistics network, as a carrier of logistics activities, is the physical foundation of the logistics managemnt. Logistics network is also a complex system, in which many optimized problems need to be solved. Hence, to study the logistcs network with complex system and optimization theories could understand runing rules of logistics activities further well and provide a new effective method and scientific foundation to research and plan the network. This dissertation mainly disscusses the complexity of logistics networks and analyses its price evolving characteristics. Logistics network design models with different conditions are proposed and logistics vehicle routing problem with fuzzy constraints is studied.The main content and innovation of this dissertation are summarized as follows:(1) Based on complex network theory, the bearing capacity of logistics networks with different topologies is studied, and optimal network structure is obtained. By considering the elastic demand condition, we analyze load distributions and bearing capacities with different parameters through artifcially created scale-free networks. The simulation results show that the load distribution follows a power-law form, which means some ordered pairs, playing the dominant role in the transportation network, have higher demand than other pairs. We also have found that, with the decrease of perceptual error, the total and average ordered pair demand will decrease and then stay in a steady state. However, with the increase of the network size, the average demand of each ordered pair will decrease, which is particularly interesting for the network design problem.(2) The spatial price problem means that if the supply price plus the transportation cost is less than the demand price, there exists a trade. And vice versa. This paper studies the evolution results of trade price in different network structures. Simulation results show that the greater the degree of random network connection and the more obvious the community structure are, the average price down faster, the system will reach equilibrium in a short time. For a scale-free network, the larger of the network size, the slower of the average price falls. These results show that the network with shorter path length is sensitive to the variation of prices.Taking into consideration the characteristics of their competition of the logistics service provider and customers, game theory and bilevel programming are used to describe the pricing of logistics services. And application example of the model and algorithm are tested, the results show that the algorithm has good convergence, other relevant parameters have different effects on the upper and lower objective function values.(3) By taking the flow uniformity into account, the location model is established to reduce the logistics resource waste and to distribute the flow uniformly. A simple solution algorithm is given and the example shows that the model is effective. Sharing market information has been recognized as an effective approach to reduce demand distortion and improve supply chain performance. This paper proposes a bilevel model to solve the location problem by considering information sharing effects. The results show that with the increase of the information sharing, the total system cost will significantly reduce. But with the further increase of the level of the information sharing, the system cost will be gradually stable. This shows that the level of information sharing will affect the interests of the logistics business and customers, a reasonable degree of the information sharing can also improve the profits of both.(4) Logistics vehicle routing problem with fuzzy constraints is studied. On the basis of previous studies,the optimizing model of logistics vehicle routing problem with fuzzy chance constraints is established, and a fuzzy analogy genetic algorithm for solving this problem is proposed. Finally, a simple experimental example is given. The result shows that this algorithm is a valid method to solve the disdeterminate problem, and have good search optimal capacity.更多还原