A comparative study between dynamic adapted PSO and VNS for the vehicle routing problem with dynamic requests

Combinatorial optimization problems are usually modeled in a static fashion. In this kind of problems, all data are known in advance, i.e. before the optimization process has started. However, in practice, many problems are dynamic, and change while the optimization is in progress. For example, in the dynamic vehicle routing problem (DVRP), new orders arrive when the working day plan is in progress. In this case, routes must be reconfigured dynamically while executing the current simulation. The DVRP is an extension of a conventional routing problem, its main interest being the connection to many real word applications (repair services, courier mail services, dial-a-ride services, etc.). In this article, a DVRP is examined, and solving methods based on particle swarm optimization and variable neighborhood search paradigms are proposed. The performance of both approaches is evaluated using a new set of benchmarks that we introduce here as well as existing benchmarks in the literature. Finally, we measure the behavior of both methods in terms of dynamic adaptation.     

Management,control, and design of integrated networks with real-time dynamic routing

Integrated real-time dynamic routing (IRR) networks provide dynamic routing features for multiple classes-of-service on an integrated transport network. In this paper it is shown that IRR networks allow reduced network management costs since with real-time dynamic routing a number of network operations are simplified or eliminated. These simplifications include eliminating the storage of voluminous routing tables in the network switches, eliminating the calculation of routing tables in network design, simplifying the routing administration operations which require downloading new routing information to the network, and eliminating the automatic rerouting function in on-line traffic management. A new bandwidth allocation technique is described here which is based on the optimal solution of a network bandwidth allocation model for IRR networks. The model achieves significant improvement in both the average network blocking and node pair blocking distribution when the network is in a congested state such as under peak-day loads. In a paper to appear in the next Journal issue we further describe a new algorithm for the transport design of IRR networks which achieves near-optimal capacity engineering. These optimization techniques attain significant capital cost reductions and network performance improvements by properly modeling the more efficient operation of IRR networks.     

一种无线传感器网络路由协议的研究与改进

无线传感器网络由许多具有低功率无线收发装置的传感器节点组成,能够有效地感知、采集和处理网络覆盖区域中的相关信息,并发送给远处的基站进一步处理。由于传感器节点能量有限,路由协议必须尽可能地减少能量消耗,延长网络生命周期。对经典的LEACH路由协议进行研究,并针对簇头节点和基站的通信方式提出改进,用M atlab平台下对LEACH算法和改进后的算法进行仿真分析,结果显示:改进后的算法在延长网络生命周期和减少能量消耗上比LEACH算法有了很大改善。     

低功耗有损网络安全路由协议研究综述

随着物联网不断飞速发展,低功耗有损网络（LLN）的研究与应用成为一种发展趋势。首先,介绍了6LoWPAN与低功耗有损网络路由协议（RPL）的基本原理和结构;其次,总结了LLN中RPL所面对的主要安全威胁以及应对方法,根据协议所采用的不同策略进行归纳、分类和比较;然后,对国内外已有安全RPL研究情况进行了介绍和分析,同时对现有安全威胁和解决方案进行了总结;最后,提出了在大规模、移动性、自组织、低功耗的RPL中需要进一步研究的安全问题和发展趋势。     

MANET能量与其他网络性能平衡路由协议

提出了一种网络性能平衡估价函数,该函数考虑了节点通信过程中的通信信息,包括节点已成功传送的数据包数、掉包数、已发送的控制包数、路由发起次数、路由总跳数以及节点的剩余能量。基于该函数,设计了一种基于能量和其他网络性能参数平衡的路由协议——BEOP,该协议通过在网络中选择平衡估价函数值小于给定阈值的节点作为路由节点,从而得到一条网络性能较优的传输路径。仿真结果表明,该协议能够很好地平衡网络性能,与DSR、MBCR协议相比,BEOP协议在网络平均时延、平均吞吐量、控制开销、丢包率、包成功发送率及网络生存时间等性能上都有较好的改善。     

面向能量和链路优化的水声移动传感器网络路由协议设计

针对水声移动传感器网络中存在水声通信环境恶劣、通信环境复杂多变以及节点能量受限造成的水声移 动传感器网络能量不均和路由链路断裂问题, 提出一种基于能量与链路度量路由的改进按需平面距离向量路由 (AODV)协议. 引入了以能量阈值为基准描述网络节点能量状态的能量指标以及以邻居节点间距离为基准描述链路 状态的链路指标, 并以综合考虑网络路由链路中节点的能量指标、路由链路指标以及路由链路跳数的路由度量作 为协议选择路径的优先条件, 并以此进行路由修复. 仿真实验表明, 本文所设计的改进AODV协议可提升网络整体 数据量、均衡网络节点能量、延长网络的生存周期.