蚁群算法解决有时间窗的车辆优化调度问题研究

有时间窗的车辆路径问题（Vehicle Routing Problem With Time Windows，VRPTW）属于NP-Hard问题，严格的时间约束使VRFTW非常复杂。应用蚁群算法（Ant Colony Algorithm,ACA）思想来解决VRPTW。对已有蚁群算法解决车辆路径优化问题（VRP）的模型进行改进，对算法中相应的转移规则和轨迹更新规则进行了重新设定，改进了算法转移策略和信息素更新策略。给出了算法的实现步骤。通过算例分析，将计算结果与遗传算法（GA）和粒子群算法（PSO）作了比较，对模型和算法的正确性、高效性、适用性进行了验证。实验结果表明，ACA可以快速、有效求得VRFTW的优化解，是求解VRFTW的一个较好方案。     

异参离散广义Nash汇流模型及应用

在广义Nash汇流理论基础上发展而来的离散广义Nash汇流模型,概念明确,结构简单,便于应用,但模型中各线性水库的调蓄参数K是相同的,致使其在河道地形(坡降和断面形状)变化较大河段应用时有其局限性。通过引入异参瞬时单位线及其S曲线,在离散广义Nash汇流模型概念解析的基础上,推导得出了异参离散广义Nash汇流模型,从而丰富了现有广义Nash汇流理论,扩大了离散广义Nash汇流模型的适用范围。实例分析表明,由于考虑了参数K的空间异质性,异参离散广义Nash汇流模型可以进一步提高河道洪水的模拟精度。     

干、支流洪水作用下洪水组合样本的选择对防洪设计的影响

不同的洪水组合样本反映的干、支流洪水变量相关性是不一样的,对防洪设计存在着一定的影响。以桂平航运枢纽水闸为例,运用Copula函数构建干流浔江年最大洪峰与支流郁江年最大洪峰、浔江年最大洪峰与相应时段郁江流量、郁江年最大洪峰与相应时段浔江流量3种洪水组合样本的联合分布,在此基础上随机模拟洪水组合经调洪计算推求防洪水位,对比这3种洪水组合样本对防洪设计的影响。研究表明:3种洪水组合样本联合分布拟合最佳的Copula函数均为Clayton Copula;浔江年最大洪峰与相应郁江洪峰流量组合样本得到的防洪水位更加合理,既不高估洪水风险也不会低估洪水风险,在经济性与安全性之间取得了较好地平衡,该组合样本推求的100a一遇防洪水位为43.54m,相比采用经验方法确定的原设计洪水位43.48m更安全。Copula-Monte Carlo法考虑了干、支流洪水间相关性以及洪水组合与调洪耦合的关系,设计结果更合理。     

基于区间入流预报的右江河道洪水演进

广西右江如果发生大洪水,将对郁江和南宁市的防洪产生严重威胁,因此右江洪水演进分析对南宁市的防洪具有重要意义。选出百色水文站洪峰流量依次增大的5场洪水,用右江百色-田东河段区间内的小流域作为代表性流域率定新安江模型参数,对区间入流洪水进行了预报。根据预报结果采用经参数试错法率定后的马斯京根模型对5场洪水进行了演进,计算了田东水文站断面的流量。结果表明:计算结果与实测流量相对误差较小,相关性系数较大,说明试错法对于马斯京根模型参数求解精度较高。     

A social activity and physical contact-based routing algorithm in mobile opportunistic networks for emergency response to sudden disasters

Sudden disasters such as earthquake, flood and hurricane necessitate the employment of communication networks to carry out emergency response activities. Routing has a significant impact on the functionality, performance and flexibility of communication networks. In this article, the routing problem is studied considering the delivery ratio of messages, the overhead ratio of messages and the average delay of messages in mobile opportunistic networks (MONs) for enterprise-level emergency response communications in sudden disaster scenarios. Unlike the traditional routing methods for MONS, this article presents a new two-stage spreading and forwarding dynamic routing algorithm based on the proposed social activity degree and physical contact factor for mobile customers. A new modelling method for describing a dynamic evolving process of the topology structure of a MON is first proposed. Then a multi-copy spreading strategy based on the social activity degree of nodes and a single-copy forwarding strategy based on the physical contact factor between nodes are designed. Compared with the most relevant routing algorithms such as Epidemic, Prophet, Labelled-sim, Dlife-comm and Distribute-sim, the proposed routing algorithm can significantly increase the delivery ratio of messages, and decrease the overhead ratio and average delay of messages.     

荆江三口分流BP网络预报模型研究

荆江三口是江湖关系调整的重要纽带.以长江干流上游来水、洞庭湖区水位以及下游顶托等影响因子为模型输入向量,运用BP网络建立了荆江三口分流流量预报模型,该模型具有1 d的预见期.预报结果表明,模型基本合理可靠.模型不仅可为荆江河段洪水演进计算提供边界条件,而且也为分析三口分流变化规律以及江湖关系等研究提供可靠依据.     

Ad Hoc 网络中的路由技术

作为下一代网络的重要组成部分，Ad Hoc网是目前的一个重要研究热点。根据Ad Hoc网络的特点，总结了Ad Hoc网中的路由技术。从路由查找和维护的角度分析和归纳了网络中关于单播路由、组播路由和QoS路由等的技术特点，指出了不同协议及算法的设计思路和解决策略，为寻求和设计更为高效的适合自组网特点的新型路由技术奠定基础。     

河道洪水演算模型评价探析

准确的洪水演算具有很强的理论及现实意义。研究了洪水演算的原理和数学模型，分析了圣维南演算模型与马斯京根演算模型的要点与难点，讨论了圣维南方程的定解条件并叙述了马斯京根演算理论，比较了两模型的优缺点及其适用情况。     

Container Forwarder Operational Management： A Local Vehicle Routing Model

The problem of local container vehicle routing is one of the most important problems for container forwarders in modem container logistics and transportation. The objective of the problem is to minimize the service cost and make the customers not exceed vehicle＇s travel time. in this paper, we propose an optimizing model of local container vehicle routing with time window constraints, which supports rail or maritime intermodal operations. Then we concentrate on developing a GA-TSP algorithm through improving solution encoding, genetic algorithm （GA） operators and involution strategy. Based on the Solomon＇s customer problem, an experimental evaluation of the proposed model is performed. It has been found that the proposed model is potentially efficient and useful in solving local container vehicle routing problems.     

一种新的自组网区域路由多径算法

能量消耗是移动自组网（MANET）路由协议研究中的一介热点所在。区域路由协议作为混合式寻路机制，为移动自组网提供了一种灵活的路由选择方式。在其路由发现的过程中，存在着多径问题，合理地利用这些路径进行路由转发，可以降低节点间功耗的偏差，使得整介网络能量消耗比较均匀。仿真表明，区域内路由部分中，该算法可较大地延长网络生存周期，而区域间路由部分所受影响则较小。