电力系统调度机组网方案分析

文章针对电力系统调度机组网的安全性、可靠性要求,指出调度交换机组网应遵循双机冗余、分级汇接的原则。以此为基础,根据河南电网的实际情况确定组网方案,在满足经济、安全性指标的前提下,对网络结构、路由选择、调度机组网功能作了系统优化。     

DIV： Dynamic Integrity Validation Framework for Detecting Compromises on Virtual Machine Based Cloud Services in Real Time

with the increasing popularity of cloud services,attacks on the cloud infrastructure also increase dramatically.Especially,how to monitor the integrity of cloud execution environments is still a difficult task.In this paper,a real-time dynamic integrity validation（DIV） framework is proposed to monitor the integrity of virtual machine based execution environments in the cloud.DIV can detect the integrity of the whole architecture stack from the cloud servers up to the VM OS by extending the current trusted chain into virtual machine＇s architecture stack.DIV introduces a trusted third party（TTP） to collect the integrity information and detect remotely the integrity violations on VMs periodically to avoid the heavy involvement of cloud tenants and unnecessary information leakage of the cloud providers.To evaluate the effectiveness and efficiency of DIV framework,a prototype on KVM/QEMU is implemented,and extensive analysis and experimental evaluation are performed.Experimental results show that the DIV can efficiently validate the integrity of files and loaded programs in real-time,with minor performance overhead.     

基于静态分簇的LEACH算法改进研究

LEACH算法是为满足高效节能需要而提出的一种典型的分簇协议.在此基础上,提出了一种改进算法：主要体现在在网络开始工作时使用静态分簇,以簇为单位进行簇内节点轮换当选为簇首,簇间以及簇与基站间的通讯采用单跳与多跳结合的方式.最后使用NS2对LEACH算法和改进的算法进行仿真对比,证实了改进后的算法在与LEACH算法相比性能有了很大的提高.     

基于泛搜索路由协议的AdHoc网络设计与实现

在AdHoc网络技术的工程实现中,路由协议的选择以及硬件无线通信系统设计是要解决的两个关键环节。本文针对节点之间无等级结构的AdHoc网络,基于一种泛搜索路由协议进行AdHoc网络系统设计和实现。硬件通信设备采用单片机C8051F920控制无线数传模块的方案进行设计,按照搜索路由协议对单片机编写程序,继而组建AdHoc网络系统。通过对网络测试所得的数据结果进行分析,表明该路由协议能适应网路拓扑结构变化,准确地找到一条适合传输的路由,所设计通信系统满足AdHoc网络的基本特征。     

不确定性自私路由模型的理论和应用

为了更加准确地描述现实生活中的交通情况,以经典的自私路由模型为基础,在边的费用函数上引入不确定性,从而定义了具有不确定性的自私路由模型.对于不确定性自私路由模型,采用三种费用衡量标准,风险厌恶型（保守型）、风险折衷型（理智型）、风险偏好型（乐观型）,分别对应着不同人群在现实中的选择.进而定义了在不同衡量标准下所形成的稳定策略,即纳什均衡策略,并且证明了在任何一种衡量标准下,纳什均衡策略总是存在并且本质是唯一的.接着对三种费用衡量标准下的纳什均衡费用进行了比较,发现了一种反直观的现象：风险厌恶型（保守型）衡量标准下的纳什均衡费用可能严格低于风险偏好型（乐观型）衡量标准下的纳什均衡费用,即有可能会出现高风险低回报,低风险高回报的情况,这与经济学中高风险高回报,低风险低回报的原则是相违背的.以此为基础,进而提出了一种自私路由风险性悖论,并证明了这种自私路由风险回报悖论本质上是传统布雷斯悖论的推广.最后,刻画出了不会发生自私路由风险回报悖论的网络结构,证明了一个单对始终点网络不会发生自私路由风险回报悖论当且仅当它是序列-平行网络.     

以商圈为中心的O2O动态外卖配送路径优化模型与算法

针对线上到线下(Online to Offline,O2O) 外卖路径优化问题,综合考虑其动态配送需求、货物区分等特点以及时间窗、载货量等约束条件,将商圈看作配送中心,将快递员数量与快递员总行驶时间作为最小化目标,提出了以商圈为中心的O2O动态外卖配送路径优化模型。采用周期性处理新订单的方法将相应的快递员路径的动态调整问题转化为一系列静态TSP子问题,设计了一种分阶段启发式实时配送路径优化算法框架,并给出了一个具体算法和一个数值计算实例。在VRP通用算例的基础上,以商圈为中心生成测试算例,对本文算法进行仿真实验,并与其他算法比较。结果表明：本文算法能充分利用新订单附近的快递员进行配送,并优化其配送路径,有效减少了快递员数量与快递员总行驶时间。     

Routing problems: A bibliography

This bibliography contains 500 references on four classical routing problems: the Traveling Salesman Problem, the Vehicle Routing Problem, the Chinese Postman Problem, and the Rural Postman Problem. References are presented alphabetically under a number of subheadings.     

一种网络负载平衡算法研究与改进

提出了一种改进的解决网络负载平衡的路由思想。利用蚂蚁具有找到最短路径,不同种类蚂蚁具有相互排斥的天然特性,和同类蚂蚁过多带来的排斥性来进行路由,从而保证网络负载分布的平衡。     

Efficient Heuristics for the Heterogeneous Fleet Multitrip VRP with Application to a Large-Scale Real Case

The basic Vehicle Routing Problem (VRP) consists of computing a set of trips of minimum total cost, to deliver fixed amounts of goods to customers with a fleet of identical vehicles. Few papers address the case with several types of vehicles (heterogeneous fleet). Most of them assume an unlimited number of vehicles of each type, to dimension the fleet from a strategic point of view. This paper tackles the more realistic tactical or operational case, with a fixed number of vehicles of each type, and the optional possibility for each vehicle to perform several trips. It describes several heuristics, including a very efficient one that progressively merges small starting trips, while ensuring that they can be performed by the fleet. This heuristic seeks to minimize the number of required vehicles as a secondary objective. It outperforms classical VRP heuristics, can easily handle various constraints, and gives very good initial solutions for a tabu search method. The real case of a French manufacturer of furniture with 775 destination stores is presented.     

Ad hoc network routing and security: A review

Ad hoc network is a collection of wireless mobile nodes dynamically forming a local area network without the use of any existing network infrastructure or centralized administration. One problem in the design of such network is its wireless vulnerabilities and limited physical security. This paper considers the security attributes and goals of ad hoc network, reviews the latest developments of current routing and security mechanissm including encryption, protocols, user authentication, and physical security. It also explores the new approaches trying to solve current problems and points out the future research directions. These methods will be helpful in the military and other security‐sensitive fields. Copyright © 2006 John Wiley & Sons, Ltd.