File Transfer Algorithm for Autonomous Decentralized System

A file transfer algorithm based on ADP (autonomous decentralized protocol) was proposed to solve the problem that the ADS (autonomous decentralized system) middleware (NeXUS/Dlink) lacks of file transfer functions for Windows. The algorithm realizes the peer-to-peer file transfer, one-to-N inquiry/multi-response file transfer and one-to-N file distribution in the same data field based on communication patterns provided by the ADP. The peer-to-peer file transfer is implemented through a peer-to-peer communication path, one-to-N inquiry/multi-response file transfer and one-to-N file distribution are implemented through multicast commtmieation. In this algorithm, a file to be transferred is named with a GUID ( global unique identification), every data packet is marked with a sequence number, and file-receiving in parallel is implemented by caching DPOs (data processing objects) and multithread technologies. The algorithm is applied in a simulation system of the decentralized control platform, and the test results and long time stable mrming prove the feasibility of the algorithm.     

Efficient peer-to-peer file sharing in 3G networks

In 3G networks upgraded with high speed packet access (HSPA) technology, the high access bandwidth and advanced mobile devices make it applicable to share large files among mobile users by peer-to-peer applications. To receive files as quickly as possible is essential for mobile users in file sharing applications, since they are subject to unstable signal strength and battery failures. While many researches present peer-to-peer file sharing architectures in mobile environments, few works focus on decreasing the time spent in disseminating files among users. In this paper, we present an efficient peer-to-peer file sharing design for HSPA networks called efficient file sharing (EFS) for 3G networks. EFS can decrease the dissemination time by efficiently utilizing the upstream-bandwidth of mobile nodes. It uses an adaptive rearrangement of a node’s concurrent uploading transfers, which causes the count of the node’s concurrent uploading transfers to lower while ensuring that the node’s upstream-bandwidth can be efficiently utilized. Our simulations show that, EFS achieves much less dissemination time than other protocols including Bullet Prime and a direct implementation of BitTorrent for mobile environments.     

A secure trust model for P2P systems based on trusted computing

Trust is one of the most important security requirements in the design and implementation of peer-to-peer （P2P） systems. In an environment where peers＇ identity privacy is important, it may conflict with trustworthiness that is based on the knowledge related to the peer＇s identity, while identity privacy is usually achieved by hiding such knowledge. A trust model based on trusted computing （TC） technology was proposed to enhance the identity privacy of peers during the trustworthiness evaluation process between peers from different groups. The simulation results show that, the model can be implemented in an efficient way, and when the degree of anonymity within group （DAWG） is up to 0.6 and the percentage of malicious peers is up to 70%7 the service selection failure rate is less than 0.15.     

求解QoS组播路由问题的改进蚂蚁算法

蚂蚁算法是一种相对较新的启发式方法,通过模拟蚂蚁的觅食行为,提出了求解Qos组播路由问题的改进蚂蚁算法。仿真实验表明,该算法能以较高速度收敛,有效地解决QoS组播路由问题。     

基于宽带接入服务器的分布式安全审计系统

用宽带接入服务器(BAS)作为分布式审计代理实现城域网(MAN)上的主动式安全审计系统．提出一种新的硬件包过滤机制(HPF)以适合系统的需要．BAS上的路由转发机制从“一次路由，多次交换”改为“一次审计，多次通过”．采用基于时间推理机的算法完成对UDP访问的审计．系统在试验网络中进行了测试，显示了很好的审计处理性能。     

Low cost and reliable anonymity protocols in P2P reputation systems

In peer-to-peer (P2P) reputation systems,each peer's trustworthiness is evaluated based on its pseudonym's rating values given by other peers. Since it is assumed that each peer has a long lived pseudonym,all the transactions conducted by the same peer may be linked by its pseudonym. Therefore,one of the fundamental challenges in P2P reputation systems is to protect peers' identity privacy. In this paper,we present two independent anonymity protocols to achieve all the peers' anonymity by changing pseudonym...     

基于移动Agent的MANET多约束QoS路由算法

针对节点能量和可用带宽2个约束条件的问题,提出了一种基于移动Agent的QoS路由算法.该算法利用移动Agent采集网络中各节点的详细信息,以最大链路的生存时间作为选择路由的基础,增强了路径的稳定性;采用多路径策略,以缩短路由重构的时间;优先选择剩余能量多的节点,延长了网络的生存时间.利用网络仿真工具NS2进行的仿真实验结果证明,与AODV协议相比,该算法具有较高的包传输率和较低的端到端平均延时.     

Power-Aware Anycast Routing in Wireless Sensor Network Exploiting Small World Effect

By considering energy-efficient anycast routing in wireless sensor network (WSN), and combining small world characteristics of WSN with the properties of the ant algorithm, a power-aware anycast routing algorithm (SWPAR) with multi-sink nodes is proposed and evaluated. By SWPAR, the optimal sink node is found and the problem of routing path is effectively solved. Simulation results show that compared with the sink-based anycast routing protocol (SARP) and the hierarchy-based anycast routing protocol (HARP), the proposed algorithm improves network lifetime and reduces power consumption.     

BitTorrent模型原理分析

BitTorrent是一个技术框架,在P2P的基本架构下定义了一个高效的文件分发模型,该模型不仅规定了文件分发中的不同实体,而且对实体之间的信息交互方式,所遵循的规范进行了严格定义,最为关键的是该协议规范中提出了分断共享的概念．在文件传输关键环节中提出的算法,使得在不稳定网络中的大文件分发更为高效．     

Research and implementation of cooperative cache for PVFS

At present, there are many effective ways to achieve high performance in cluster system storage management, including server-end disk, server-end caching, local caching and cooperative caching. The cooperative caching mechanism shares caches among different clients so as to avoid expensive disk access costs and to improve overall throughput of cluster system. In this paper, a Single Copy Cooperative Cache model is proposed together with block lookup algorithm, block replacement algorithm and the consistency algorithm based on the model. Meanwhile, the prototype system of the model is implemented in PVFS file system. Finally, the performance of this system is tested in InfiniBand Framework, the result of which shows that in contrast to the original PVFS system, read performance of PVFS file system is improved by about two times, while write performance is reduced by nearly ten percent.     

基于定长帧的组播QoS路由技术

为高效利用网络资源且平衡负载,结合物理帧时槽交换技术,提出了基于定长帧的组播机制和QoS路由算法MRBP.该算法在满足带宽和时延要求的基础上,最小化时延和平衡节点负载,达到组播树总体时延较小并优化利用网络资源的目的.仿真结果表明,基于该算法建立的组播树具有较好的网络负载平衡性,并能够对服务质量提供较好的保证.     

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针对一类动态车辆路径问题,分析4种主要类型动态信息对传统车辆路径问题的本质影响,将动态车辆路径问题(Dynamic Vehicle Routing Problem, DVRP)转化为多个静态的多车型开放式车辆路径问题(The Fleet Size and Mixed Open Vehicle Routing Problem, FSMOVRP),并进一步转化为多个带能力约束车辆路径问题(Capacitated Vehicle Routing Problem, CVRP),基于CVRP模型建立了DVRP模型;然后,在分析DVRP问题特点基础上,提出两阶段算法,第一阶段基于利用K-d trees对配送区域进行分割的策略,提出了复杂度仅为O(nlogn)的快速构建型算法,第二阶段通过分析算法搜索解空间结构原理,设计混合局部搜索算法;最后,基于现有12个大规模CVRP标准算例,设计并求解36个DVRP算例。求解结果表明了模型和两阶段算法的有效性。     

一种基于二叉树的P2P网络查找算法

针对P2P网络中资源查找以及其自身存在的问题,提出了一种基于二叉树的P2P网络模型。该模型借鉴了可信计算中的直接匿名认证机制、DHT、超级节点的思想,在此基础上设计了一种高效的可扩展查找算法,解决P2P网络查询延迟、冗余信息、可扩展性等关键问题。模拟实验表明,该算法能够有效减少网络带宽消耗并能显著提升P2P网络的查找效率。     

一类动态车辆路径问题模型和两阶段算法

针对一类动态车辆路径问题,分析4 种主要类型动态信息对传统车辆路径问题的本质影响,将动态车辆路径问题(Dynamic Vehicle Routing Problem, DVRP)转化为多个静态的多车型开放式车辆路径问题(The Fleet Size and Mixed Open Vehicle Routing Problem, FSMOVRP),并进一步转化为多个带能力约束车辆路径问题(Capacitated Vehicle Routing Problem, CVRP),基于CVRP模型建立了DVRP模型;然后,在分析DVRP 问题特点基础上,提出两阶段算法,第一阶段基于利用K-d trees 对配送区域进行分割的策略,提出了复杂度仅为O(nlogn)的快速构建型算法,第二阶段通过分析算法搜索解空间结构原理,设计混合局部搜索算法;最后,基于现有12 个大规模CVRP标准算例,设计并求解36个DVRP算例.求解结果表明了模型和两阶段算法的有效性.     

WDM全光网络中的多播路由与波长分配算法

研究了全光网络中的多播路由和波长分配问题，结合波长图模型，提出了一种波长可变WDM全光网络的多播路由和波长分配算法，算法将路由和波长分配统一进行，通过动态调整节点与当前树的代价值构造时延受限低代价多播树，避免了同类算法的较高复杂性。     

基于冲突回避的动态滑行路径算法

为解决机场场面航空器滑行路径分配问题,在时间依赖最短路径算法的基础上,提出了基于冲突回避的动态滑行路径分配算法.根据机场场面交通的实际情况,定义了3种不同类型的滑行冲突以及航空器的滑行优先级.给出了在不同类型冲突和不同滑行优先级情况下的滑行道时间延误函数.仿真实验表明,当跑道运行飞机达到32架次/h时,与固定路径相比,动态路径运行的航空器平均滑行时间减少了3 min/架次,航班延误减少了3.5 min/架次.     

An Effective Hybrid Optimization Algorithm for Capacitated Vehicle Routing Problem

IntroductionVehicle routing problem(VRP)is a well-known combinatorial optimization problem and isalso a focal problem of distribution managementwithin the area of service operations managementand logistics.Capacitated vehicle routing problem(CVRP)is a very hard vehicle routing problem.The problem is to simultaneously determine theroutes for several vehicles from a central depot to aset of customers,and then return to the depotwithout exceeding the capacity constraints of eachvehicle.In prac…     

一种基于节点异质性降低跳图维护代价的方法

Skip Graphs提供了一种新的P2P查找算法,但是其系统查询和维护的消息流量巨大,限制了其应用.本文通过构造节点异质性模型,充分考虑节点异质性和节点负载的关系,提出新的Skip Graphs＋＋算法,有效降低系统的维护代价10%～30%,并从理论和仿真两方面进行证明.     

无线传感器网络分簇路由协议分析

路由技术是无线传感器网络研究的关键技术之一,分簇路由协议成为目前重点研究的路由技术。分析了无线传感器网络分簇路由机制,着重从分簇路由簇头的产生、簇的形成和簇的路由的3个过程。系统地分析了当前典型的分簇路由算法,并进一步提出了算法未来的研究重点。     

基于蚂蚁算法的动态分布式路由算法

提出了一种利用蚂蚁算法进行动态更新分布式路由表的方法,该方法以路由表中的信息素强度和当时链路的负载状况为基础,来选择路由和更新路由表,给出了更新路由表的规则并利用计算机进行了仿真验证.仿真结果表明,蚂蚁算法可兼顾路由长度和网络负载两方面的因素,其选路效果优于传统动态分布式算法.