基于Gossip算法的无线传感器网络时间同步

将Gossip算法用于实现无线传感网络的分布式时间同步,提出单Gossip同步算法和多Gossip同步算法,解决传统无线传感器网络时间同步算法中存在的计算复杂度高和同步收敛速度慢等问题.单Gossip同步算法首先利用构造生成树算法得到一个生成树,然后,依次对生成树每条边的两节点时钟信息进行Gossip运算,反复循环,最终可使网络各节点的时钟信息收敛于它们初始时钟信息的平均值.多Gossip同步算法对生成树进行边染色,相同染色的边可以同时进行Gossip运算.这2种同步算法减小了消息交换数,降低了计算复杂度,提高了同步的收敛速度.用随机矩阵理论和图论进行了理论证明,通过计算机仿真对理论分析进行了数据验证.     

浅评凯瑟琳·诺瑞斯的《the Holy Use of Gossip》(英文)

本文从主题分析的个人特征、写作风格的特点及写作技巧方面,浅评了美国女作家凯瑟琳.诺瑞斯的《the holy use of Gossip》,认为该部作品是一个作者把自己对“流言”这个主题自由的表述和和写作技能完美结合的典范。     

基于结构化Gossip协议的网格服务发现

在动态的网格环境中分布着大量不同类型的服务和资源.快速、准确地进行资源与服务发现,是影响网格计算性能的关键因素,因此,建立了一种基于消息扩散的网格服务发现机制.提出了一种新型的结构化Gossip消息扩散算法,简称为S-Gossip,此算法具有良好的冗余性和完备性.我们详细的描述了此算法及其协议的实现,并在此基础上建立了层次化的服务发现模型.     

Rise and Fall of the Peer-to-Peer Empire

The essence of the peer-to-peer design philosophy is to design protocols for end hosts, or "peers", to work in collaboration to achieve a certain design objective, such as the sharing of a large file. From a theoretical perspective, it has been recognized that the peer-to-peer design paradigm resembles gossip protocols, and with appropriate algorithmic design, it maximizes the network flow rates in multicast sessions. Over the past ten years, research on peer-to-peer computing and systems, a unique and intriguing category of distributed systems, has received a tremendous amount of research attention from academia and indus-try alike. Peer-to-peer computing eventually culminated in a number of successful commercial systems, showing the viability of their design philosophy in the Internet. The peer-to-peer design paradigm has pushed all design choices of innovative protocols to the edge of the Internet, and in most cases to end hosts themselves. It represents one of the best incarnation of the end-to-end argument, one of the frequently dis-puted design philosophies that guided the design of the Internet. Yet, research on peer-to-peer computing has recently receded from the spotlight, and suffered from a precipitous fall that was as dramatic as its me-teoric rise to the culmination of its popularity. This article presents a cursory glimpse of existing results over the past ten years in peer-to-peer computing, with a particular focus on understanding what has stimulated its rise in popularity, what has contributed to its commercial success, and eventually, what has led to its pre-cipitous fall in research attention. Our insights in this article may be beneficial when we develop our thoughts on the design paradigm of cloud computing.     

会话通信模式下的二阶系统队形控制算法

研究二阶多智能体系统的队形控制问题。假设平面上一群智能体和一个静止的锚节点，在会话通信模式下仅利用角度信息为每个智能体设计分布式控制器，控制加速度输入使得它们最终形成以固定锚节点为中心的平衡圆周队形，并给出仿真图验证结果。     

分布式流言push-sum无梯度算法

研究多个体网络中所有个体目标函数之和最小值问题,其中每个个体仅知其自身目标函数且仅可与其邻居个体交互信息。鉴于个体目标函数通常非光滑,同时个体间单变量信息通信有一定局限性,本文提出一种分布式流言push-sum无梯度算法求解此优化问题。假设每个个体都具有一个服从泊松分布的控制时钟,时钟的每次转动表示随机选择的个体之间进行信息更新。进一步地,在网络连通条件下证明了所提算法的收敛性。数值仿真结果表明,与现有的分布式流言无梯度优化算法相比,本文算法具有更快的收敛速度。     

基于可扩展交换网络的高效轻量级故障检测器

针对可扩展交换网络的故障检测器需要在保证扩展灵活性的同时提高故障发现效率并减少产生的信息负载,通过改进现有分层流言协议,提出了局部定向分层流言协议,并证明了基于局部定向分层流言协议的故障检测器可以解决可扩展交换网络的合意问题。仿真实验的结果表明:基于局部定向分层流言协议的故障检测器在故障发现效率和减少产生的负载两方面均优于基于现有的分层流言故障检测器。     

浅析电视连续剧《媳妇的美好时代》的艺术性

36集电视连续剧《媳妇的美好时代》,受到了广大观众的好评和热捧,为什么这部并非大片的电视连续剧如此吸引观众,文章对剧作进行了分析,认为该剧主要在以下三个方面吸引观众:家长里短却不失时代特点;轻松幽默又不失严肃思考;并非大腕却演技淋漓尽致。     

A probabilistic characterization of a fault-tolerant gossiping algorithm

Gossiping is a popular technique for probabilistic reliable multicast (or broadcast). However, it is often difficult to understand the behavior of gossiping algorithms in an analytic fashion. Indeed, existing analyses of gossip algorithms are either based on simulation or based on ideas borrowed from epidemic models while inheriting some features that do not seem to be appropriate for the setting of gossiping. On one hand, in epidemic spreading, an infected node typically intends to spread the infection an unbounded number of times (or rounds); whereas in gossiping, an infected node (i.e., a node having received the message in question) may prefer to gossip the message a bounded number of times. On the other hand, the often assumed homogeneity in epidemic spreading models (especially that every node has equal contact to everyone else in the population) has been silently inherited in the gossiping literature, meaning that an expensive membership protocol is often needed for maintaining nodes’ views. Motivated by these observations, the authors present a characterization of a popular class of fault-tolerant gossip schemes (known as “push-based gossiping”) based on a novel probabilistic model, while taking the afore-mentioned factors into consideration. This work is supported in part by the US National Science Foundation. The views and conclusions contained in the paper are those of the authors and should not be interpreted as, in any sense, the official policies or endorsements of the government or the agencies.