DSR的一种自适应路由自动缩短机制

动态源路由协议是无线自组织网络众多路由协议中被广泛关注的一种按需路由协议，目前，关于该协议的优化措施有很多。本文先分析了动态源路由协议的一种优化机制——路由自动缩短，该机制能动态缩短处于工作状态路由的跳数，但不保证缩短路由的质量，在此基础上，提出一种自适应路由自动缩短机制，新机制既可缩短路由．又能保证缩短路由质量．理论分析及仿真结果表明，自适应路由缩短机制的各项性能优于原路由缩短机制。     

Isolation and identification of a sulfate reducing bacteria and sequence analysis of its dissimilatory sulfite reductase gene

A sulfate reducing bacteria was isolated from mining sewage of Daqing Oilfield by Hungate anaerobic technology. Physiological-biochemical analysis showed that the strain could utilize polyacrylamide as sole carbon and nitrogen source. The sequence analysis of 16S rDNA illustrated that the similarity of F8 and Desulfovibrio desulfuricans (AF192153) was 99%, and the similarity sequence of dissimilatory sulfite reductase gene (DSR) cloned from the strain and Desulfovibrio desulfuricans (AF273034) was 98%. Their phylogenitic analysis was basically anastomosed, and thus temporarily named as Desulfovibrio desulfuricans F8. The DSR cloned from F8 strain was 2740 bp in length consisting of three ORF, DSRA, DSRB and DSRD as a single operon (DSRABD) regulated by the same operator. DSRA contained typical conservative box of sulfate—sulfite reducing enzyme (SiteⅠand SiteⅡ), which could bind siroheme and [Fe4S4]. DSRB retained a [Fe4S4] binding site, with an uncomplimentary structure for siroheme binding. There was no conservative box in DSRD. Sequence analysis of DSR will provide a theoretical basis for quantitative detection, metabolic pathway modification through gene engineering, and sulfate reducing bacteria (SRB) suppression.     

MANET中基于蚁群算法的改进DSR协议*

为提高移动Ad hoc网络中DSR协议的服务质量,提出基于蚁群算法的改进DSR协议---ACOIDSR。ACOIDSR协议路由发现过程中,建立稀疏模式和稠密模式弥补DSR协议泛洪策略的不足;ACOIDSR协议路由选择过程中,利用路径长度、拥塞程度和链接可靠度计算每条路径的信息素数量,进而做出最佳路径的选择;ACOIDSR协议路由维护过程中,提出一种新的信息素衰退策略用于路由维护。最后,仿真实验用于ACOIDSR协议在端到端的延迟、路由负载以及能量消耗等方面分析。     

基于备份路由的DSR协议改进*

在按需路由协议DSR基础上,选择最少相交点路由,综合考虑带宽、延迟因素提出了DSRBACKUP路由协议。通过选取一条符合最低要求的较优路由作为备份,以此来减轻振荡对QoS保障造成的影响。经仿真分析,DSRBACKUP路由协议在合适的路由开销下,提高了QoS数据流性能的稳定性,达到预期效果。     

GloMoSim中DSR协议实现分析

仿真是目前研究Ad hoc网协议和算法的廉价、有效手段。分析目前流行的网络仿真软件Glo-Mosim的控制流程,并且详细分析移动自组网路由协议DSR在GloMoSim中的设计与实现,重点分析DSR的路由请求处理、路由回复处理、路由错误处理、丢包处理、路由处理等必要操作。     

AODV和DSR无线移动网络路由协议性能分析

分析了DSR和AODV两种AdHoc典型反应式路由协议的原理．介绍了网络仿真的一般过程．在NS2平台上对两种协议进行了仿真．并对仿真结果进行了分析．     

不同网络负载的Ad Hoc网络路由协议性能分析

通过实验对一种表驱动路由协议(DSDV)以及其中两种按需式路由协议(DSR和AODV)协议的性能进行比较和分析.利用NS-2仿真软件,设计了基于不同网络负载的多组仿真模型,并根据模型进行仿真.之后从分组投递率、时延和路由负荷三个性能指标参数对仿真结果进行了比较.实验结果表明:按需式路由协议DSR和AODV要优于基于表驱动的路由协议DSDV;在两种按需式路由协议之间,随着不同网络负载的加重,AODV协议比DSR协议的性能优势越来越明显.同时分析了造成不同协议之间性能差距的原因,针对AODV协议提出了今后的改进方向.     

Linear and nonlinear viscoelastic and viscoplastic analysis of asphalt binders with warm mix asphalt additives

Warm-Mix Asphalt (WMA) is a widely used product, which proved a contribution to the reduction in asphalt mixing and compaction temperatures. This reduction leads to lower fuel consumption and smoke emission in asphalt plants. Most of the characterisation of binders used in WMA has focused in the past on measuring linear viscoelastic properties and associated Superpave parameters. Several studies have shown that the average stresses and strains of the asphalt mixture remain mostly within the linear viscoelastic response. However, localised strains in the binder phase of the mixture could reach values high enough to induce nonlinear viscoelastic and viscoplastic deformations. Therefore, this study focuses on an experimental and analytical evaluation of linear, nonlinear viscoelastic and viscoplastic responses of selected binders modified for use in WMA. The first part of the paper analyses the linear viscoelastic material properties and their ability to evaluate permanent deformation resistance. Then, the non-recoverable creep compliance parameter obtained from the Multiple Stress Creep Recovery (MSCR) test is analysed to assess the nonlinear response and permanent deformation of asphalt binders. The paper utilises a nonlinear plasto-viscoelastic (NPVE) approach to assess and quantify the nonlinear plasto-viscoelastic response of binders by separating the recoverable and irrecoverable strains measured in the MSCR test. Two WMA additives were included in this study by mixing them with polymer-modified and unmodified asphalt binders. Analysis of results showed that the NPVE approach captured a higher percentage of recovery than the NLVE approach. However, binder’s performance evaluation and ranking did not change by adopting the NPVE approach. The nonlinear viscoelastic parameters provided insight on the behaviour of asphalt binders mixed with WMA additives during loading cycles. Sasobit showed higher influence than Advera on binders in resisting permanent deformation by increasing the recoverable strain during the unloading phase.     

移动Ad-hoc经典路由协议仿真与比较

路由协议选择的方法一般是通过网络仿真器对不同协议进行对比分析,其结果作为协议选取的依据。该文以DSR协议为例,介绍了仿真过程的详细步骤,并对Ad hoc网络经典路由协议DSR和AODV协议进行对比分析。结果表明,在动态的环境下,AODV的分组投递率和路由负载优于DSR路由协议。     

基于改进离散PSO算法的DSR协议

提出一种基于改进离散粒子群优化算法的DSR协议——P-DSR.引入智能代理作为粒子,将求解Ad hoc网络的最优路由问题等效为0-1组合优化问题,将链路稳定因子作为粒子群优化算法的适应值函数.仿真结果表明,与传统DSR协议相比,P-DSR协议具有较低的端到端时廷及较高的数据包投递率.