一种SDN中基于SR的多故障恢复与规避机制

针对SDN中的多故障恢复问题,提出了一种基于分段路由的多故障恢复与规避机制.为实现故障的快速恢复,在数据平面通过SR技术预部署一个可对多故障提供快速恢复能力的链路环备份系统;为防止故障恢复时造成部分链路负载过重引发再故障,提出最优化流量平滑算法对负载超过设定阈值的链路实施流量均衡处理.实验结果表明,与已有的SDN多故障恢复机制OAM-Based和Fast Failover相比,所提机制的平均故障恢复成功率分别提高了6.7%和8.5%,且控制器通信开销仅为传统OpenFlow方案的9%,同时,所提机制对故障恢复时导致的链路负载过重问题进行了处理,从故障规避的角度为网络提供保护.     

Bio‐inspired packet dropping for ad‐hoc social networks

Ad‐hoc social networks (ASNETs) explore social properties of nodes in communications. The usage of various social applications in a resource‐scarce environment and the dynamic nature of the network create unnecessary congestion that might degrade the quality of service dramatically. Traditional approaches use drop‐tail or random‐early discard techniques to drop data packets from the intermediate node queue. Nonetheless, because of the unavailability of the social properties, these techniques are not suitable for ASNETs. In this paper, we propose a Bio‐inspired packet dropping (BPD) algorithm for ASNETS. BPD imitates the matching procedure of receptors and epitopes in immune systems to detect congestions. The drop probability settings depend on the selection of data packets, which is based on node popularity level. BPD selects the most prioritized node through social properties, which is inspired by the B‐cell stimulation in immune systems. To fairly prioritize data packets, two social properties are used: (1) similarity and (2) closeness centrality between nodes. Extensive simulations are carried out to evaluate and compare BPD to other existing schemes in terms of mean goodput, mean loss rate, throughput, delay, attained bandwidth, and overhead ratio. The results show that the proposed scheme outperforms these existing schemes. Copyright © 2014 John Wiley & Sons, Ltd.     

基于STM32的双足避障机器人设计

本文计了一种基于STM32的双足避障机器人,机器人主体使用超轻材质的铝合金搭建,结构稳定可靠,环境适应能力强.采用高性能的STM32单片机为系统主控芯片,配合外围传感器信息采集系统和舵机驱动控制系统,能够完成自主行走,躲避障碍,路径规划等任务.经实验验证,该机器人系统能很好的实现自主避障行走,可以有效减少机器人在避障行走中对环境的依赖性,满足设计要求.     

Interference avoidance strategy for ultra dense network with pilot reuse

In the ultra dense network (UDN),the pilot reuse scheme would produce significant interference,which will affect the accuracy of channel estimation.To solve this problem,an interference avoidance strategy for UDN with pilot reuse was proposed.An interference model of subcarriers for UDN was provided and the interference probability of subcarriers was derived.Then,based on the model,a pilot position selection model was proposed and an interference avoidance strategy for UDN with pilot reuse was provided.The simulation results show that compared with the traditional channel estimation algorithm,the channel estimation with proposed interference avoidance strategy can effectively avoid the interference and ensure the accuracy of channel estimation in UDN with pilot reuse.     

毫米波雷达高压线检测技术的研究进展

高压线是威胁飞行器低空安全飞行的主要障碍,高压线的准确检测和有效预警是毫米波低空防撞雷达最重要的功能需求之一。首先介绍了毫米波雷达高压线检测技术的研究现状,其次重点分析了高压线的电磁散射特性、检测算法和检测系统三个主要方面的研究进展,提出了毫米波防撞雷达应具备大空域扫描、高数据更新率、高分辨率、小目标检测和抗杂波干扰等特点,最后指出了高压线检测技术的未来发展趋势,即基于多传感器信息融合检测、自主学习的智能化检测和深度信息检测。     

小型高精度防撞雷达信号处理系统实现

针对国内汽车防撞雷达领域存在问题,研究小型化高精度防撞雷达信号处理系统实现方案,详细分析信号处理流程,确定合适的雷达信号处理方法。结合系统结构和处理方案计算出适合驾车环境的系统参数,通过系统仿真验证其有效性。并在小型化和低成本的条件下,提出基于Super SVA方法实现目标距离分辨率的提高。确保雷达系统不会因为成本问题限制其检测性能。最后,对实例化样机进行外场功能测试,测试数据分析结果验证了系统方案的可行性。     

带有移动Sink的传感器网络回路避免跟踪协议

无线传感器网络通常被应用于收集大规模网络中的传感数据,这些收集工作由Sink完成。为了降低网络内能量空洞产生的概率,延长网络寿命,目前多采用移动Sink收集数据。文中提出了一种带有移动Sink的数据收集协议。该协议中,Sink节点能根据相邻足迹节点间坐标夹角的变化,有效回避掉那些回路上的足迹节点,而只保留非回路上的足迹节点。仿真实验结果表明,LAT协议可显著提升数据查询效率,并有效延长了网络寿命。     

一类非齐次障碍问题很弱解的正则性

本文研究形如divA(x,▽u)=B(x,▽u)的非齐次椭圆算子的障碍问题,给出了二阶非齐次障碍问题解的定义,并利用Hodge分解,获得非齐次障碍问题的解及其导数的一些性质.     

简易智能电动车的设计

智能小车采用TI公司的MSP430F2274单片机作为核心控制芯片,由液晶显示模块、电机驱动模块、传感器模块、电源模块组成。在机械结构上,用两个直流电机作为两个前轮,再外加一个从动轮,使小车的转向更加灵敏。采用PWM驱动芯片控制电机,红外LED和一体化接收头来避障。基于可靠的硬件设计和稳定的软件算法,实现避障、测速等功能。     

适于多跳移动Ad Hoc网络的非对称双信道媒质接入控制协议

In order to resolve the hidden and exposed terminal problems and improve the probability of concurrent packet transmissions for multihop Mobile Ad Hoc Networks (MANETs), a novel slotted Asymmetric Dual-Channel Medium Access Control (ADC-MAC) protocol is proposed. It exploits simultaneous reservation with less collisions and collision-free data packet transmissions, and achieves optimal transmission balance on the Control Channel (CCH) and Data Channel (DCH) by adjusting the relationship between Reservation Slot (RS) on the CCH and the data packet Transmission Slot (TS) on the DCH. Transmission interferences can be avoided by only observing CCH for the transmission time of a data packet. The proposed RS and contention micro-slot backoff mechanisms also greatly improve channel access efficiency. Simulation results show that compared to IEEE 802.11 DCF and p-Mc protocols, the proposed protocol can achieve a throughput gain of 88% in single-hop networks and 151% in multihop networks at the same total data rate.