Nature Inspired Improved Firefly Algorithm for Node Clustering in WSNs

Wireless Sensor Networks (WSNs) comprises low power devices that are randomly distributed in a geographically isolated region. The energy consumption of nodes is an essential factor to be considered. Therefore, an improved energy management technique is designed in this investigation to reduce its consumption and to enhance the network’s lifetime. This can be attained by balancing energy clusters using a meta-heuristic Firefly algorithm model for network communication. This improved technique is based on the cluster head selection technique with measurement of the tour length of fireflies. Time Division Multiple Access (TDMA) scheduler is also improved with the characteristics/behavior of fireflies and also executed. At last, the development approach shows the progression of the network lifetime, the total number of selected Cluster Heads (CH), the energy consumed by nodes, and the number of packets transmitted. This approach is compared with Ad hoc On-Demand Distance Vector (AODV), Dynamic Source Routing (DSR) and Low Energy Adaptive Clustering Hierarchy (LEAH) protocols. Simulation is performed in MATLAB with the numerical outcomes showing the efficiency of the proposed approach. The energy consumption of sensor nodes is reduced by about 50% and increases the lifetime of nodes by 78% more than AODV, DSR and LEACH protocols. The parameters such as cluster formation, end to end delay, percentage of nodes alive and packet delivery ratio, are also evaluated... The anticipated method shows better trade-off in contrast to existing techniques.     

Mesh网下AODV、DSR和ZigBee路由的比较分析

为了研究在Mesh拓扑网络下不同无线自组网络路由协议的性能优劣,在网络设计中有选择地使用,分析和研究了ZigBee路由、动态源路由协议（DSR）和平面距离矢量路由协议（AODV）三种无线自组网络路由协议的思想和原理。通过网络模拟软件NS-2,在其他外部条件相同的条件下对三者在Mesh拓扑结构组网进行模拟,得到端到端平均延迟、包传输率和路由开销率三种性能指标的折线图。从仿真结果图上看,ZigBee路由在其应用范围内具有独特优势,适合在Mesh拓扑网络中应用。     

TLA改性沥青流变和老化性能的研究

采用动态剪切流变仪（DSR）对不同掺量的11A改性沥青的流变性能进行了研究,并通过薄膜烘箱老化（TFOT）和紫外老化（uv）试验研究了TLA对沥青老化性能的影响。结果表明：加入TLA后,沥青的复数模量增大,相位角减小,TLA的掺量每增加10％,PG高温区间基本上升1个等级,大大提高了沥青的高温稳定性和降低了其温度敏感性。与未改性沥青相比,TLA改性沥青TFOT和UV老化后的软化点增量和粘度变化指数显著减小,TFOT老化后的残留针入度比明显增大,TLA的加入有效地改善了沥青的热氧老化和紫外老化性能。     

基于MANET可用性的信任度量模型

提出并设计了基于可用性的信任度量模型(ABTEM,availability based trust evaluation model),在此基础上可以构建多种针对可用性的安全服务.网络模拟实验的结果证明,将ABTEM应用于DSR路由协议时,在路由层能够成功地根据其恶意行为发现网络中的恶意节点,并且进一步孤立这些恶意节点,从而避免网络继续受到恶意节点的侵害,显著提高了MANET系统的可用性.     

一种有效的具有负载意识的按需路由协议

移动Ad hoc网络是由一组无线移动终端构成的临时性网络,不依赖于固定的基站或现有的有线骨干网。由于网络拓扑结构动态变化的特性和网络资源的有限性,开发一种性能优越的Ad hoc网络路由协议是一项具有挑战意义的工作。在本论文中,提出了一种有效的具有负载意识的按需驱动路由方案。该方案将网络负载信息作为路由选路的主要标准。对提出的方案作了仿真,并且和Dynamic Source Routing（DSR）协议进行了比较。结果表明网络负载在总体上得到了平衡,包传递率和平均端到端时延的性能也得到了有效的改善。     

DSR协议cache管理策略的优化

针对DSR协议不能充分利用潜在路由信息、路由缓存中过期路由影响路由选择准确性以及存在数据分组额外开销较大的问题,从cache管理策略方面提出了一种优化方案——采用链路缓存与“超时”机制相结合的方法,减小数据分组头的开销,充分利用潜在路由信息,保证路由缓存中路由选择的准确性。仿真结果表明,优化后的协议能够显著降低网络开销及时延。     

无线Ad Hoc网络支持QoS的路由协议研究

当前,Ad Hoc网络传输多媒体业务需求提出了服务质量（QoS）的要求。由于Ad Hoc网络本身具有分布式控制、无线信道容量受限以及节点、链路和网络拓扑状态不断变化等特点,使其相对于固定无线网络及有线网络提供有保证且稳定的QoS要困难得多。文章总结了当前DSR协议的QoS研究进展,对不同的改进方案加以分类比较,指出了存在的问题：并针对hdHoc网络中基于资源预留的QoS算法所带来的复杂度问题,提出了适合该网络的测量可用带宽算法,构造了一种支持实时业务的Ad Hoc网络QoS服务机制。     

一种新型的能量受限无线体域网路由协议

针对无线体域网这种新型的应用场景,设计了一种新型的能量受限无线体域网路由协议EE-DSR。该协议在DSR路由基础上,综合考虑了无线体域网中信道变化、节点业务类型和节点服务时间等特殊应用,有效地节省了网络传输的能量消耗,从而较好地延长了网络生存期。     

Investigation of rutting performance of asphalt binders containing warm additive

In this research study, permanent deformation of pure and zycotherm modified binders were evaluated. Conventional test results showed that all percentages of zycotherm reduce susceptibility of binders to temperature. G^*/sinδ values of dynamic shear rheometer revealed that addition of zycotherm improves performance of binders against permanent deformation. Likewise, results of multistress creep recovery test indicated that zycotherm decreased the nonrecoverable compliance (Jnr) values, which is an indication of lower susceptibility of asphalt binders against rutting distress. According to test results, 0.1% of zycotherm is proposed to have the highest impact on performance of AC 85/100 asphalt binders against permanent deformation.     

分布式电源的配电网重构和电容器优化投切

综合考虑最优潮流、配电网重构和电容器优化投切,建立了计及分布式电源的配电网经济运行模型。鉴于模型的复杂性,采用结合最优潮流和改进蚁群算法的混合优化方法进行求解。该方法将最优潮流嵌入改进蚁群算法中,利用最优潮流求解考虑网络安全约束的分布式电源优化调度问题,利用改进蚁群算法优化配电网结构和电容器档位。为了提高蚁群算法的优化效率,建立含有局部搜索蚂蚁的混合蚁群,平衡蚁群算法的全局和局部搜索能力。通过对16节点和33节点的测试系统仿真,表明提出的模型和算法正确有效。