一种具有较好用户体验的P2P因特网视频广播系统

针对当前流行的P2P因特网视频广播系统频道切换慢、源到端时延长等问题,进行了连接节点管理算法和数据段调度算法的研究,提出了一种采用基于多树和网的方案MTreeTV,降低了时延并能适应自治节点的高波动.该方法充分利用了结构化P2P覆盖网的优点,能够扩展到非常大的规模,网络效率和健壮性较好.理论分析和仿真表明,MTreeTV可以提供较短的频道切换和源端时延(小于9s)并具有很高的播放连续性,而且控制开销较小(小于2%).此外还研究了缓冲区大小、连接节点数量、节点带宽和节目速率等关键参数对P2P因特网视频广播系统性能的影响.     

基于P2P的网络存储系统的研究

本文在介绍P2P技术及P2P网络存储系统的基础上,设计了一个基于P2P的网络存储系统,通过P2P技术将网络中各个节点连接起来形成一个虚拟存储空间。该系统可以充分发掘用户计算机的作用,发挥P2P技术在文件交换方面的优势。     

结构化P2P网络中资源搜索问题的研究

资源搜索问题是P2P网络的核心问题之一,也是P2P网络研究的热点。本论文选定结构化P2P网络作为研究对象,通过为Chord网络中每个节点增加一个指取表,完成了Chord网络基本路由算法的改进,提高了路由效率及减少了查询消耗时间。最后利用P2P协议仿真平台p2psim,仿真了Chord搜索算法。     

TSS-SON:一种基于结构化P2P网络路由的两级语义覆盖网络结构

提出了基于结构化P2P网络路由机制的两级语义覆盖网络结构TSS-SON.该结构根据资源主题将节点组织成主题区域,在同一主题区域内,采用基于语义相似度机制进行群的划分.该结构充分利用了结构化P2P网络的优点,解决了基于非结构化P2P网络建立的语义覆盖网络对主题群的搜索低效问题,同时克服了结构化P2P网络仅支持精确匹配查找的缺点,实现了可靠、高效的语义查询,并极大地提高了查全率.     

一种基于P圈的ASON混合故障保护模型

在研究自动交换光网络(ASON)中发生节点/链路混合故障时的保护方法的基础上,设计了一种同时考虑节点故障和链路故障情况的基于P圈的保护模型,同时给出了一种保证在混合故障时可以达到100%业务恢复率的预配置P圈保护的启发式算法,并且综合考虑了实际网络中保护恢复速度和资源效率等因素,给出了具有最大P圈跳数限制的P圈配置方案.利用OPNET软件搭建了ASON仿真平台,在泛欧Cost239网络拓扑和北美NSFnet网络拓扑上,采用静态业务模型对该算法进行了仿真分析.仿真结果证明,该算法在拥有故障业务快速恢复能力的同时,相比已有算法具有更低的资源冗余度.     

无结构化P2P网络的路由算法

针对无结构化P2P网络的洪泛搜索与随机漫步机制的盲目性,提出了一种利用Hash函数与M-tree技术将文件聚类后,再利用路由表完全分布式存储索引指针的新的路由算法。该算法使每个节点的路由表主要记录拥有各类资源的高能力节点指针,并利用概率统计的方法不断地更新路由表项。当节点收到搜索以后,通过查询路由表,只需一跳就进入能以最大概率回应的节点处查找,并能以较低的网络时延命中多个优质资源副本,达到了高速并行下载的目的。仿真试验和数学分析表明该算法有效地减少了盲目搜索造成的网络流量,提高了查找成功率,并且具有越稀缺的资源越容易找到的特性。     

P2P-SIP技术之我见

SIP协议是当前VolP和IM等多媒体协议的呼叫建立协议。P2P技术提供了分布式的网络架构中通信节点之间得对等通信能力,P2P网络架构经历了集中目录式网络架构、纯P2P网络架构、混合式P2P网络架构和结构化P2P网络架构。通过引入P2P技术,SIP网络的能力可以得到增强。     

数字认证在P2P中的应用

在很多未来网络发展的文章中,经常能看到关于P2P的字眼.P2P是未来网络的热门关键词,由于P2P很多技术及标准还处于研制和探讨的过程中,结合目前的P2P与安全中的数字认证,猜想数字认证在未来网络中的发展,提出P2PSMS,一个基于P2P的安全系统模型,描述用户在P2P网络平台中与主动节点实现密码PKI认证等过程.     

基于网络编码的P2P内容分发性能分析

P2P网络是一种全新的第三代网络拓扑结构，是一种分散式的网络架构，采用的是点对点的方式，这种网络结构在文件共享，对等计算，搜索引擎等方面都拥有很多的优点，本系统是在P2PN络的基础上，应用JxTA架构来完成的一个平台，JXTA结构是一种混合P2P搜索模式的网络协议，平台优势在与对于内容分发性能和下栽软件的设计操作简单，系统稳定，所以在软件的设计中，经常会运用该类型的架构和性能分析。     

基于P2P网络的分级路由策略分析

在P2P网络中定位节点非常重要。由于不同拓扑结构的P2P网络采用各种不同的路由方式,对P2P网络的分级路由方式进行分析,揭示基于P2P网络的分级路由策略。     

Mathematical Model Validation of Search Protocols in MP2P Networks

Broadcasting is a basic technique in Mobile ad-hoc network (MANET), and it refers to sending a packet from one node to every other node within the transmission range. Flooding is a type of broadcast where the received packet is retransmitted once by every node. The naive flooding technique, floods the network with query messages, while the random walk technique operates by contacting the subsets of every node’s neighbors at each step, thereby restricting the search space. One of the key challenges in an ad-hoc network is the resource or content discovery problem which is about locating the queried resource. Many earlier works have mainly focused on the simulation-based analysis of flooding, and its variants under a wired network. Although, there have been some empirical studies in peer-to-peer (P2P) networks, the analytical results are still lacking, especially in the context of P2P systems running over MANET. In this paper, we describe how P2P resource discovery protocols perform badly over MANETs. To address the limitations, we propose a new protocol named ABRW (Address Broadcast Random Walk), which is a lightweight search approach, designed considering the underlay topology aimed to better suit the unstructured architecture. We provide the mathematical model, measuring the performance of our proposed search scheme with different widely popular benchmarked search techniques. Further, we also derive three relevant search performance metrics, i.e., mean no. of steps needed to find a resource, the probability of finding a resource, and the mean no. of message overhead. We validated the analytical expressions through simulations. The simulation results closely matched with our analytical model, justifying our findings. Our proposed search algorithm under such highly dynamic self-evolving networks performed better, as it reduced the search latency, decreased the overall message overhead, and still equally had a good success rate.     

面向服务的P2P网络体系结构 层次参考模型研究

提出了一种基于交互、 面向服务的P2P网络体系结构框 架模型ISPNA,同时结合P2P网络 松耦合、自组织、可缩放等特点, 对P2P网络技术中增强其可用性需 要解决的关键问题进行分析。 从P2P网络体系结构的研究角度出发, 将增强P2P网络可用性所需要考虑的 多方面因素放置在P2P网络的不同 层次予以解决,有利于从宏观上 把握需要解决的问题。     

MINE: A Method of Multi-Interaction Heterogeneous Information Network Embedding

Interactivity is the most significant feature of network data, especially in social networks. Existing network embedding methods have achieved remarkable results in learning network structure and node attributes, but do not pay attention to the multiinteraction between nodes, which limits the extraction and mining of potential deep interactions between nodes. To tackle the problem, we propose a method called MultiInteraction heterogeneous information Network Embedding (MINE). Firstly, we introduced the multi-interactions heterogeneous information network and extracted complex heterogeneous relation sequences by the multi-interaction extraction algorithm. Secondly, we use a well-designed multi-relationship network fusion model based on the attention mechanism to fuse multiple interactional relationships. Finally, applying a multitasking model makes the learned vector contain richer semantic relationships. A large number of practical experiments prove that our proposed method outperforms existing methods on multiple data sets.     

一种支持范围查询的P2P动态负载平衡算法

为支持连续数据按范围分段存放的P2P系统的动态负载平衡,使用了局部负载平衡算法和基于负载目录的负载平衡算法相结合的方法:局部负载平衡算法使负载交换只在邻居节点间进行,保证了相邻节点的负载始终处于平衡状态;基于负载目录的负载平衡算法使用负载目录克服了负载聚集时对节点进行均匀随机采样困难的问题,负载交换在负载目录中的所有节点中进行,使得系统能够以很高的概率满足全局负载平衡条件.算法分析和实验结果表明,这种方法可以取得较好的动态负载平衡效果.     

Single Failure Routing Protection Algorithm in the Hybrid SDN Network

Loop free alternate (LFA) is a routing protection scheme that is currently deployed in commercial routers. However, LFA cannot handle all single network component failure scenarios in traditional networks. As Internet service providers have begun to deploy software defined network (SDN) technology, the Internet will be in a hybrid SDN network where traditional and SDN devices coexist for a long time. Therefore, this study aims to deploy the LFA scheme in hybrid SDN network architecture to handle all possible single network component failure scenarios. First, the deployment of LFA scheme in a hybrid SDN network is described as a 0-1 integer linear programming (ILP) problem. Then, two greedy algorithms, namely, greedy algorithm for LFA based on hybrid SDN (GALFAHSDN) and improved greedy algorithm for LFA based on hybrid SDN (IGALFAHSDN), are proposed to solve the proposed problem. Finally, both algorithms are tested in the simulation environment and the real platform. Experiment results show that GALFAHSDN and IGALFAHSDN can cope with all single network component failure scenarios when only a small number of nodes are upgraded to SDN nodes. The path stretch of the two algorithms is less than 1.36.     

网络时代的三大基本定律与骨干网容量的演进

文章首先分析了新时期的巨大挑战及其对网络的深远影响,特别指出了网络面临的巨大容量压力。接下来分别就主宰网络时代的三个基本定律：摩尔定律、光纤定律和迈特卡尔夫定律的内涵、影响和技术极限进行了论述。最后探讨了骨干网传输链路、传送节点和业务节点的容量演进策略。     

A Hybrid Method for Structural System Reliability‐Based Design Optimization and its Application to Trusses

Most research studies on structural optimum design have focused on single‐objective optimization of deterministic structures, while little study has been carried out to address multi‐objective optimization of random structures. Statistical parameters and redundancy allocation problems should be considered in structural optimization. In order to address these problems, this paper presents a hybrid method for structural system reliability‐based design optimization (SRBDO) and applies it to trusses. The hybrid method integrates the concepts of the finite element method, radial basis function (RBF) neural networks, and genetic algorithms. The finite element method was used to compute structural responses under random loads. The RBF neural networks were employed to approximate structural responses for the purpose of replacing the structural limit state functions. The system reliabilities were calculated by Monte Carlo simulation method together with the trained RBF neural networks. The optimal parameters were obtained by genetic algorithms, where the system reliabilities were converted into penalty functions in order to address the constrained optimization. The hybrid method applied to trusses was demonstrated by two examples which were a typical 10‐bar truss and a steel truss girder structure. Detailed discussions and parameter analysis for the failure sequences such as web‐bucking failure and beam‐bending failure in the SRBDO were given. This hybrid method provides a new idea for SRBDO of trusses. Copyright © 2015 John Wiley & Sons, Ltd.     

An Influence Maximization Algorithm Based on Improved K-Shell in Temporal Social Networks

Influence maximization of temporal social networks (IMT) is a problem that aims to find the most influential set of nodes in the temporal network so that their information can be the most widely spread. To solve the IMT problem, we propose an influence maximization algorithm based on an improved K-shell method, namely improved K-shell in temporal social networks (KT). The algorithm takes into account the global and local structures of temporal social networks. First, to obtain the kernel value Ks of each node, in the global scope, it layers the network according to the temporal characteristic of nodes by improving the K-shell method. Then, in the local scope, the calculation method of comprehensive degree is proposed to weigh the influence of nodes. Finally, the node with the highest comprehensive degree in each core layer is selected as the seed. However, the seed selection strategy of KT can easily lose some influential nodes. Thus, by optimizing the seed selection strategy, this paper proposes an efficient heuristic algorithm called improved K-shell in temporal social networks for influence maximization (KTIM). According to the hierarchical distribution of cores, the algorithm adds nodes near the central core to the candidate seed set. It then searches for seeds in the candidate seed set according to the comprehensive degree. Experiments show that KTIM is close to the best performing improved method for influence maximization of temporal graph (IMIT) algorithm in terms of effectiveness, but runs at least an order of magnitude faster than it. Therefore, considering the effectiveness and efficiency simultaneously in temporal social networks, the KTIM algorithm works better than other baseline algorithms.     

一种P2P文件共享系统汇聚拥塞控制机制

针对现有P2P文件共享系统采用并发多连接的文件传输方式,过分占用网络带宽资源,导致其它传统互联网业务性能低下的问题,提出了一种P2P文件共享系统汇聚拥塞控制机制(ACCM).ACCM采用应用层网络测量技术感知节点接入网链路拥塞状况,依据网络拥塞状况动态地调整P2P文件共享系统并发文件传输连接窗口,在最大化网络带宽利用率的基础上实现对传统互联网应用的友好性.网络实验结果表明,在网络拥塞发生时,ACCM能够促使P2P文件共享系统并发连接窗口主动退避,实现和传统互联网应用的和平共处;在网络空闲时,ACCM能够促使P2P文件共享系统扩大并发连接窗口,提高网络带宽资源的利用率.     

P(AM-co-AMPS)基凝胶的溶胀动力学研究

本文以丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为有机单体、正硅酸乙酯(TEOS)为无机原料合成了P(AM-co-AMPS)基水凝胶,研究了凝胶的相转变温度,以及在相转变温度前后的溶胀性能和溶胀动力学。结果表明,P(AM-co-AMPS)凝胶在25℃水温下主要以大分子松弛为主的溶胀方式,而在0℃水温下为Fickian扩散方式,且具有一定的温敏性;P(AM-co-AMPS)/SiO2杂化凝胶在0℃和25℃均保持非Fickian扩散方式,且温敏性被掩盖。