优化蚁群算法在网络知识路由系统中的应用

研究网络知识路由问题,提高网络资源搜索质量。针对传统方法在网络资源搜索过程中,存在搜索时间长,得不到最优解,导致搜索速度慢,效率低的问题。为了提高网络资源搜索效率,提出一种基于改进蚁群的路径搜索算法,在混合信息素更新策略,自适应挥发因子等方面进行改进,并设置了先行蚂蚁和后行蚂蚁。该方法有效地避免了蚁群搜索陷入局部最优,加快了收敛,提高了搜索效率。仿真结果表明,改进方法缩短了搜索时间,网络资源搜索效率明显提高,证明是一种有效的优化方法,能够在最短时间找到资源搜索的最优解,是解决网络资源搜索优化问题的有效算法。     

IMS路由相关问题及安全分析

IMS采用会话启动协议（SIP）作为主要信令协议,运行于IP网络之上,是下一代融合网络核心的可选方案之一。IMS中和路由相关的描述主要包括：SIP消息中与路由有关的消息头描述、用户注册路由描述、用户会话发起路由描述,用以解决注册路由和会话路由等。在IMS的部署结构和路由的过程中,接口受到的安全威胁最大,需要设备商和运营商之间根据实际情况达成共识,来提高网络的健壮性和安全性.由于普遍采用简单易实现的递归查询方式,从而导致一级服务器查询量大,需要减少查询开销。     

QoS‐aware routing and power control algorithm for multimedia service over multi‐hop mobile ad hoc network

This paper presents a QoS (quality of service) aware routing and power control algorithm consuming low transmission power for multimedia service over mobile ad hoc network. Generally, multimedia services need stringent QoS over the network. However, it is not easy to guarantee the QoS over mobile ad hoc network since its network resources are very limited and time‐varying. Furthermore, only a limited amount of power is available at mobile nodes, which makes the problem more challenging. We propose an effective routing and power control algorithm for multimedia services that satisfies end‐to‐end delay constraint with low transmission power consumption. The proposed algorithm supports the required bandwidth by controlling each link channel quality over route in a tolerable range. In addition, a simple but effective route maintenance mechanism is implemented to avoid link failures that may significantly degrade streaming video quality. Finally, performance comparison with existing algorithms is presented in respect to traditional routing performance metrics, and an achievable video quality comparison is provided to demonstrate the superiority of the proposed algorithm for multimedia services over mobile ad hoc network. Copyright © 2010 John Wiley & Sons, Ltd.     

物联网分布式路由中基于Beta函数的抗攻击信任管理模型

With the rapid development of Internet of Things (IoT), the issue of trust in distributed routing systems has attracted more research attention. The existing trust management frameworks, however, suffer from some possible attacks in hostile environments, such as false accusation, collusion, on-off, and conflicting behavior. Therefore, more comprehensive models should be proposed to predict the trust level of nodes on potential routes more precisely, and to defeat several kinds of possible attacks. This paper makes an attempt to design an attack-resistant trust management model based on beta function for distributed routing strategy in IoT. Our model can evaluate and propagate reputation in distributed routing systems. We first describe possible attacks on existing systems. Our model is then proposed to establish reliable trust relations between self-organized nodes and defeat possible attacks in distributed routing systems. We also propose a theoretical basis and skeleton of our model. Finally, some performance evaluations and security analyses are provided to show the effectiveness and robustness of our model compared with the existing systems.     

稀疏波长变换网络性能分析与研究

文章对动态业务模型下的稀疏波长变换网络性能进行了分析与研究，对波分复用（WDM）网络中引入波长变换器后的网络性能进行了系统的仿真，分析了波长变换器数量、波长变换器位置、波长变换范围以及路由波长算法等因素对网络性能的影响。     

自动交换光网络E-NNI研究

本文研究了自动交换光网络E-NNI的定义、参考位置和E-NNI业务调用配置方式.分析了E-NNI路由、信令和保护恢复及自动发现的协议进展、需求、框架和实现方式.     

FPGA的静态功耗分析与降低技术

FPGA已经被广泛用于实现大规模的数字电路和系统,随着CMOS工艺发展到深亚微米,芯片的静态功耗已成为关键挑战之一。文章首先对FPGA的结构和静态功耗在FPGA中的分布进行了介绍。接下来提出了晶体管的漏电流模型,并且重点对FPGA中漏电流单元亚阈值漏电流和栅漏电流进行了详细的分析。最后根据FPGA的特点采用双阈值电压晶体管,关键路径上的晶体管采用低阈值电压栅的晶体管,非关键路径上的晶体管采用高阈值电压栅的晶体管,以此来降低芯片的静态功耗。     

典型航空自组网路由协议仿真与性能评估

航空自组网是自组网在航空领域的典型应用.航空自组网的关键技术在于路由协议的选取和设计.基于场景用NS2软件仿真研究了3种适用于航空自组网的路由协议及其网络性能,并定义了4个性能评估准则.仿真结果表明,单跳距离一定时,3种路由协议的网络性能随着节点密度的增加而总体变差.同等条件下,AODV路由协议路由开销高于DSVD和GRID路由协议,端到端平均延时低于DSVD和GRID路由协议,而GRID协议分组投递率和平均跳数保持最高.     

移动Ad hoc网络基于干扰和连通度的路由协议

移动Ad hoc网络中,节点随机移动会引起通信链路频繁断开,从而导致路由失效,带来大量的路由重建与路由发现,耗费了有限的网络资源。传统按需路由中,采用简单的洪泛进行路由发现,路由请求包的盲目转发会带来大量不必要的冗余转发,造成广播风暴问题。此外,大量的数据包同时发送也会对彼此的传输造成干扰,增加数据包冲突概率。针对这种情况,本文提出一种基于干扰和连通度的路由协议,该协议结合节点的连通度和潜在干扰设计转发概率,不仅减少了路由请求包的传播范围,还减少了路由请求包的冲突概率,提高了传输成功率。仿真结果表明,本文设计的方案在减少路由开销的同时,有效提高了数据包投递率,从而提高了路由性能。     

基于分解协调的SWCC-OBS网络路由选择研究

针对稀疏分布有限波长转换能力的光突发交换(SWCC-OBS)网络容易出现的高丢包率和负载不均 衡问题,建立了稀疏分布OBS全网丢包率的数学模型。为了克服模型求解过程中多 变量带来的非 线性问题,对影响全网突发丢包率的参变量进行分解预估和反馈更新,求得全网对应业务流 模型下的优化 路由路径,获得了全网突发数据的近似最低丢包率。仿真实验表明,在SWCC-OBS网络中, 本文提出的路由 选择模型及分解协调的路由选择算法,不仅能有效地避免突发数据包间的相互冲突、降低了 全网丢包率,而 且能很好地适应突发数据业务的动态变化,保证了网络的负载均衡和较低的丢包率。