Ad Hoc网络路由协议可扩展性仿真研究

我们利用G1oMoSim仿真工具建立了一个合理的Ad Hoc网络模型,并设计了一个完整的仿真方案对3种Ad Hoc网络路由协议AODV、DSR及DBF进行了全面的性能仿真。通过比较它们的平均报文接收率、平均端到端时延及控制报文的比例得出了AODV协议的可扩展性优于其它两种协议的结论。同时得出了现有的AODV协议同样不适合大规模网络的结论。     

移动无线mesh网络路由协议关键问题研究

为设计和改进适合MWMNs的路由协议,分析了MWMNs路由协议性能的主要影响因素,设计了MWMNs路由协议应首先考虑的链路可用性问题,在此基础上对DSR协议应用于MWMNs进行了可行性分析。研究结果显示,DSR协议由于动态机制还不够完善,没有考虑链路的可用性和可用时间等问题,并不能完全适用于MWMNs。     

面向环境监测的WSN中基于定向传输的高能效路由算法

能耗问题是WSN在环境监测中发展与应用中的主要限制因素,而路由协议成为解决Qos(即能耗、网络生命周期、网络可扩展性和包开销等)相关问题的研究热点.动态路由协议适用于能量密度较小的场景,但当节点模式从活跃转睡眠时,数据包需要等到下一个发送时间点才能发送,从而降低网络能效、增加数据包的端到端时延,进而增加了网络能耗.为了解决该问题,本文提出了一种基于PEGASIS与DSR联合优化的路由协议JPDORP(Joint PEGASIS-DSR Optimized Routing Protocol),JPDORP有PEGASIS和DSR协议的共同特征,同时也融合运用了遗传算法和细菌觅食优化方法以确定能效最优的传输路径.仿真结果表明,算法在误比特率、时延、能耗、吞吐量方面均有增益,能够提供更好的Qos保障和延长网络生命周期.     

LPDSR:基于Chord算法的MANET分级路由模型

为提高移动自组织网络(mobile ad hoc network,MANET)路由协议效率并增强其网络可扩展性,通过对P2P(peep-to-peer)网络与MANET的交叉研究,在DSR协议基础上引入Chord算法,提出基于网络物理拓扑的分级路由模型LPDSR.采用按需建环机制和分级路由算法,降低查询复杂度,减少绕路问题.LPDSR算法性能分析和NS-2仿真结果表明,该路由模型的网络可扩展性明显提高.     

基于动态源路由协议的无线网状网络研究

目前,在无线网络研究领域,为无线网状网络（WMN）设计一个完善的路由协议是现在的研究热点之一。无线网状网络（WMN）与Adhoe网络有许多共同属性,尤其是在它结点的静态特性方面,无线网状网络（WMN）有自己一些独特的特征,其相邻结点间的跳数保持不变。无线网状网络（WMN）的静态特性结构所需的网络协议更注重链接质量而不是跳数,因此论文以动态源路由协议（DSR）为基础来检测链路链接的质量,同也考虑了单个链接延迟的影响因素,将协议的量度方式由跳数改为链接质量。     

Decomposing global solar radiation into its diffuse and direct normal radiation

ABSTRACT

This work presents a model based on Radial Basis Function (RBF) to estimate the diffused solar radiation (DSR) and direct normal radiation (DNR) fractions of solar radiation from global solar radiation in a semiarid area in Algeria based on a database measured between 2013 and 2015. The data has been collected at Applied Research Unit for Renewable Energies, (URAER) at Ghardaia city situated in the south of Algeria. The experimental results show that RBF model estimates DNR and DSR with high performance. The difference between the measured and the predicted values show a normalised Root Mean Square Error (nRMSE) of 0.033 and 0.065 for DNR and DSR, respectively. The obtained values of Determination Coefficient (R²) and Correlation Coefficient (R) are: 97.3%, 98.60%, respectively for DNR and 88.89%, 91.12% For DSR.

However, the obtained results are very plausible and showed that RBF model estimates the DSR and DNR with good accuracy.     

A comparison of two approaches for incorporating air voids in asphalt pavement oxidation modeling with a multiyear,multisite set of field core data

Pavement oxidation modeling has been used to predict pavement aging, or more specifically, oxidation and hardening. Two approaches for incorporating pavement air voids in the modeling analysis have been developed—the cylindrical approach and the diffusion depth (d_D) approach. The work reported herein compares these approaches with a multiyear, multisite set of field data. The d_D approach produces field calibration factor values that are closer to theory, and is better able to predict aging variation with pavement depth. Results suggest the presence of undetected smaller air voids, in agreement with previous work.     

Rheological evaluation of ethylene vinyl acetate polymer modified bitumens

The morphological, thermal and fundamental rheological characteristics of ethylene vinyl acetate (EVA) copolymer modified bitumens are studied in this paper. Nine plastomeric EVA polymer modified bitumens (PMBs) have been produced by laboratory mixing bitumen from three sources with an EVA copolymer at three polymer contents. The morphology, thermal properties and rheological characteristics of the EVA PMBs have been analysed using fluorescent microscopy, differential scanning calorometry and dynamic mechanical analysis using a dynamic shear rheometer, respectively. The results of the investigation indicate that EVA polymer modification increases binder stiffness and elasticity at high service temperatures and low loading frequencies with the degree of modification being a function of bitumen source, bitumen–polymer compatibility and polymer concentration. Filler type modification is evident at low temperatures, temperatures above the melting temperature of the semi-crystalline EVA copolymer and for those modified binders that do not exhibit a dominant polymer network.     

两种改性沥青的微观结构试验研究

利用现代测试手段,如红外光谱（IR）、热重（TG）、扫描电镜（SEM）分析的方法,对基质沥青、SBS改性沥青和胶粉改性沥青进行了试验。分析了沥青的微观结构及改性沥青性能。结果表明：基质沥青为均相结构,SBS改性沥青为亚均相结构;废胶粉与沥青能够均匀混合,既有物理共混又有化学反应,形成稳定的非均相结构;胶粉颗粒的表面网状结构可很好的吸附沥青,使沥青粘度增大,感温性降低,为改性沥青的应用提供了理论依据。     

无线Ad Hoc网络DSR与OLSR路由协议的性能比较

文中首先从理论出发,对Ad Hoc网络中的两种典型路由协议：DSR与OLSR进行了比较分析,然后利用OPNET网络仿真软件搭建仿真模型,在业务数据持续发送的环境下,对DSR和OLSR的性能进行了对比测试,最终我们发现OLSR在仿真环境中全面领先于DSR,其代价是更高的存储复杂度、更多的运算复杂度和更大的节点能量消耗。