Optimal Routing in Gossip Networks

In this paper, we introduce the Gossip Network model where travelers can obtain information about the state of dynamic networks by gossiping with peer travelers using ad hoc communication. Travelers then use the gossip information to recourse their path and find the shortest path to their destination. We study optimal routing in stochastic, time-independent gossip networks, and demonstrate that an optimal routing policy may direct travelers to make detours to gather information. A dynamic programming equation that produces the optimal policy for routing in gossip networks is presented. In general, the dynamic programming algorithm is intractable; however, for two special cases a polynomial optimal solution is presented. We show that ordinarily gossiping helps travelers decrease their expected path cost. However, in some scenarios, depending on the network parameters, gossiping could increase the expected path cost. The parameters that determine the effect of gossiping on the path costs are identified and their influence is analyzed. This dependency is fairly complex and was confirmed numerically on grid networks.     

Children's Social Behavior in Three Towns with Difering Television Experience

Although an initial displacer of social engagement, television may ultimately foster increased interpersonal contact by serving as a focal point for shared activities.     

二进制指数退避的Gossip算法研究

为减少Gossip算法进行信息传播的通信开销,该文提出一个将二进制指数退避算法与经典Gossip算法相结合的二进制指数退避的Gossip算法(BEBG),其信息传播策略是一个节点收到同一信息的次数越多,继续传播该信息的概率就越低。理论分析与仿真实验表明,BEBG能够有效减少信息传播冗余,网络中有10⁴个节点时比经典Gossip算法减少了约61%网络负载。为解决BEBG存在的边缘节点问题,进一步提出了两个BEBG改进算法,引入Pull的PBEBG和引入向邻居节点Push的NBEBG。实验结果表明,两个算法能够消除边缘节点,当网络中有10⁴个节点时,它们与相应的分别引入相同Pull和Push的经典Gossip算法相比,分别减少了约34%和37%的网络负载。     

Regional Gossip Routing for Wireless Ad Hoc Networks

Many routing protocols have been proposed for wireless ad hoc networks, and most of them are based on some variants of flooding. Thus many routing messages are propagated through the network unnecessarily despite various optimizations. Gossip based routing method has been used and re-investigated to reduce the number of messages in both wired networks and wireless ad hoc networks. However, the global gossiping still generates many unnecessary messages in the area that could be far away from the line between sender node and receiver node. We propose a regional gossip approach, where only the nodes within some region forward a message with some probability, to reduce the overhead of the route discovery in the network. We show how to set the forwarding probability based on the region and the network density both by theoretical analysis and by extensive simulations. Our simulations show that the number of messages generated using this approach is much less than the simple global gossiping method, which already saves many messages compared with global flooding. We expect that the improvement should be even more significant in larger networks.     

网格环境下一种改进的Gossip资源聚集算法

网格计算和对等计算有很多可以融合的特征.首先提出了一种集成P2P模式的网格资源管理模型,然后针对传统的Gossip资源聚集算法的弊端,利用小世界理论,提出了一种改进的Gossip资源聚集算法.理论分析和仿真证明了改进的Gossip算法能够有效地聚集资源信息,从而提高P2PGrid环境下的资源聚集性能.     

量化状态信息下多智能体Gossip算法及分布式优化

基于量化状态信息的异步随机Gossip算法大多以均匀选择概率的时间模型为基础,未充分考虑网络拓扑结构对局部信息传递的影响。为此,该文提出了一种以非均匀选择概率为时间模型的改进算法。首先给出了非均匀选择概率下的多智能体系统时间模型,在随机性量化策略下给出了一致性误差的收敛性质;并讨论了量化精度和概率化权重矩阵第2大特征值对一致性误差收敛速度的影响,进而利用投影次梯度给出了选择概率的分布式优化方法。仿真结果表明,该基于量化状态信息的算法可通过选择概率的分布式优化,提高一致性误差的收敛速度。     

元件

RF功率MOSFET STMicroelectronics公司的SD29XX系列全金属化N沟道MOSFET RF功率晶体管,额定功率值从5W、28V到300W、50V。采用特殊的内部封装技术,其无支架式设计使热阻降低了25％,平均故障间隔时     

元器件

低成本、3引脚硅振荡器 Maxim最新推出MAX73 75硅振荡器,采用节省空间的3引脚SC70或SOT23封装,芯片内部集成了固定频率的振荡器,省去了任何设置或调节频率的外部元件.     

元器件

激光二极管驱动器 美国国家半导体公司(NS)推出多款可缩短台式及笔记本计算机50%写入及重写时间的激光二极管驱动器.     

元器件

新型的环境亮度传感器 安捷伦科技公司日前推出环境亮度传感器,通过消除不必要的背光,提高手机电池的工作时间,而其成本和体积只是以前产品的一半.