世界航运网络的结构特性及其动力学行为研究

【作者】 熊文海；

【导师】 张嗣瀛；

【作者基本信息】 青岛大学 ， 系统理论， 2009， 博士

【摘要】 世界海洋运输系统是典型的复杂系统,它是由数百个港口和数以千计的船舶组成的,而且这些港口和船舶的数量是随时间演化的,在空间上,船舶与港口之间的联系也是千差万别的,因此对其进行整体性研究存在许多的困难,现今的研究方法仍然采用还原论的思想,将其分成子系统进行研究,虽然也得到了一些有益的成果,但是缺失了许多系统整体的信息。网络是对现实系统的一种数学抽象,它描述了系统元素之间相互作用的关系,是一种用整体论的思想来研究系统的有效工具,正因为如此,本文从复杂网络的视角,将世界海洋运输系统中的每个港口看作网络中的节点,将港口与港口之间通过船舶进行货物转移的相互联系看作网络中节点与节点之间边的连接关系,把世界海洋运输系统抽象为一种复杂网络拓扑图——世界航运网络图,这种图直观地体现了世界海洋运输系统中各个港口之间复杂的关联关系。本文以世界海洋运输系统为研究对象,从复杂网络的视角,利用统计分析与比较分析相结合、定性分析与定量分析相结合的方法对其进行了深入的研究,遵循着从世界航运网络的构建到网络结构统计属性的实证分析,再到寻找形成这种网络结构的机理,最后研究这种网络结构会出现什么样的动力学行为的思路开展研究工作。具体而言,本文在以下几个方面对世界航运网络进行了研究:1)根据连续的观察、调研以及对航运系统充分了解的基础上,构建了一个世界航运网络图,该图具有加权、有向和包含空间维度等特性。随后从无权和加权两个方面对网络的结构特性进行了系统的研究,得到了一系列测度参量的分布特征,比如,度、强度分布、网络特征谱表现出无标度特性;网络的平均路径长度很小以及网络簇系数却很大等特性,也就是说世界航运网络同样是一个小世界网络。除此之外,还对网络测度参数之间的相关性进行了研究,结果表明网络同时具有加权网络特性和空间网络特性,这些特性是许多其它复杂网络不曾具有的。2)系统的结构决定了系统的功能和行为,那么为什么世界航运网络会呈现这样的结构特性呢?这也就成为了本文需要解决的首要问题,本文作者根据长期调研世界海洋运输系统运行演化规律的结果,并结合前面统计分析得到的世界航运网络的一些结构参量分布特性,对世界航运网络的演化机理进行了深入的研究,建立了交通流驱动的世界航运网络模型和空间距离限制的世界航运网络模型,这些模型能够很好地再现世界航运网络的某些结构特性。3)社团结构虽然是一个社会学中的概念,但是它同系统中的传播动力学有着密切的联系,因此也是人们关注的焦点。世界航运网络中的社团结构同样值得我们的关注,因为我们可以从中发现世界各个国家之间的贸易往来联系紧密程度以及网络中交通流的分布情况,因此本文还对世界航运网络中社团结构的定义、划分标准以及划分具体的算法进行了系统的研究,得到了最优的社团个数,同时还解释了为什么在世界航运网络中会出现这样的结构划分。4)世界航运网络是典型的基础设施系统网络,它的效率和安全性一直是人们关注的焦点,特别是当系统受到一些意外的因素(比如像战争、恐怖袭击以及极限自然环境的干扰)影响时,系统是否依然能够表现出稳健性。另一方面系统的动力学行为必然能够反映出系统结构特性,因此最后本文还对世界航运网络的动力学行为进行了研究——鲁棒性研究,以此来验证我们所得到的系统结构特性是否准确。通过对世界航运网络的结构特性以及动力学行为的研究,我们可以宏观地了解各个国家之间的贸易联系,为分析各种地区间经济联系提供佐证;可以为建立新航线、合理分布航线、提高网络效率提供理论参考;可以为今后港口建设规划提供理论支持。更多还原

【Abstract】 The global maritime shipping system is a typical complex system,it is composed by hundreds ports and thousands ships,the quantities of ports and ships are evolving with time,the relationships among them differ largely in spatial,so there exist many difficulties in researching this system in holism.Nowadays the methodology of exploring global shipping system still adopting reductive ideology,partitioning it to some subsystems for researching,some useful results have been concluded,but these results lose some integral information of system.Network is a mathematical abstract to real system,it characterizing the interactions among system elements,so it is a very useful holistic approach for researching complex system.Based on it,this dissertation regards the ports as nodes and regards the cargo flow among ports as interactive edges from complex network view,so the global maritime shipping system is characterized by a complex network topology graph-global shipping network,this graph directly embodies the complex interactions among ports of global maritime shipping system.In this dissertation,the global maritime shipping system is studied using complex network theory,combining the statistical with comparative analysis methods,quantitative with qualitative analysis methods.The research work was carried out following the route from constructing global shipping network to analyzing structure properties,then exploring the evolving mechanism of this particular structure,finally,discussing whatever dynamical behavior emerged from this network structure.Specifically,this dissertation exploring global shipping network from these aspects:1)Based on consecutive observation and investigation,this dissertation constructs a directed and weighted global shipping network which embedded in a spatial lattice.Then we study a set of measurements of unweighted and weighted global shipping network and attain distributing properties of some typical parameters,for example,we find the average path length of this network is so small but the cluster coefficient is very large,the degree and strength distribution following power-law.Moreover we also explore the correlation between these measurement,the results indicate that the global shipping network containing weighted as well as spatial property.2)The structure of system determines the function and behavior of system,the next question is why the global shipping network presents such structure? Combining the long-term investigating the evolution laws of global maritime shipping system with the statistical results attained from above,we research the evolving mechanism of the global shipping network in detail,construct a traffic driven network model and a geographical constraints network model,all the two model can reproduce some structure properties of global shipping network.3)Community is a conception using in sociology,meanwhile it associating with spread dynamics of system,so it becomes a hot topic.We can find the closeness trading between different countries and traffic distribution among network throng communities, we give the specific definition and partition criteria of community in global shipping network,moreover we introduce a concrete algorithm to find community in global shipping network,and obtain the best partition,at the same time,we shed light on the reasons leading to this partition.4)The global shipping network is a typical infrastructure network,people give much attention to its efficiency and safety,especially,focus on robustness of system when encountered accidental events(such as war,terrorist attack and perturbation of atrocious environment).On the other hand,the dynamical behavior of system must reflect the structure of system,so the last part of dissertation discusses the dynamical behavior of global shipping network,using it we can validate the accuracy of system structure obtained from our results.Through exploring the structure properties and dynamical behavior of global shipping network,we can understand the trading relationship among different countries macroscopically and provide proofs of analyzing local economic relations.Secondly,we can provide theoretical consult for constructing new line,distributing line fairly, improving system efficiency.Thirdly,we can provide theoretical support of designing new port.更多还原