无线充电及其在图像采集粮虫检测传感器网络中的应用

随着科技的发展,无线充电技术在各个领域的应用也越来越广泛,比如在手机、电脑、相机、汽车等行业的部分最新产品中已经使用了无线充电技术。介绍了一种简便高效的无线充电方案,应用于埋入式图像采集粮虫检测系统,以确保传感器网络节点能够方便、安全、稳定地工作。该系统的工作环境特殊,无线充电技术有无需物理接触的优势,可以合理有效地替代传统的有线充电方法。使用高度集成的XKT-408A作为系统的发射芯片,再配合极少的外部元件就可以制作可靠稳定的无线充电器,不仅保证了无线充电的传输效率,也大大降低传感器网络节点的体积。     

Active Queue Management for Fair Resource Allocation in Wireless Networks

This paper investigates the interaction between end-to-end flow control and medium access control (MAC)-layer scheduling on wireless links. We consider a wireless network with multiple users receiving information from a common access point; each user suffers fading and a scheduler allocates the channel based on channel quality but is subject to fairness and latency considerations. We show that the fairness property of the scheduler is compromised by the transport-layer flow control of transmission control protocol (TCP) New Reno. We provide a receiver-side control algorithm, CLAMP, that remedies this situation. CLAMP works at a receiver to control a TCP sender by setting the TCP receiver's advertised window limit, and this allows the scheduler to allocate bandwidth fairly between the users.     

无线环境下具有实时约束的主动队列管理机制

实时流业务的超期丢包率是衡量无线网络传输过程服务质量的常用参数,但是该参数并不能反映出具有不同重要度的数据包对视频质量的影响。该文将实时传输流的数据包重要度与超期丢包率结合,提出加权超期丢包率的概念,更加准确地描述丢包与视频质量的关系,在无线环境下提出基于数据包不同重要度的适用于实时约束流的主动队列管理算法,通过主动丢弃数据包以最小化服务过程中实时流的加权超期丢包率。仿真结果表明,相比于传统的队列管理算法和实时视频流滤波器算法,该超期数据包主动丢弃算法能够有效降低加权超期丢包率,提供更好的服务质量,提高大约0.5~1.5 dB的峰值信噪比(PSNR)增益。     

无线充电技术Qi

针对近两年蓬勃发展的无线充电技术,分析了消费者应用层面的需求,介绍了现在常见的充电技术,再深入分析了现行唯一已制定并公开标准的无线充电联盟之Qi技术,包括其工作原理,标准的内容及认证流程等。     

无线充电收获季节即将到来

对移动设备而言,电池充电是非常重要的使用流程之一.你是否曾经厌倦带着各种不同设备的充电器去旅行,你是否为了找到一条匹配的充电电缆而翻箱倒柜,在这些时候,如果可以摆脱这些电缆的束缚,该是多么美好的体验,为此无线充电技术应运而生.     

磁感应或磁共振,哪个更适合于无线充电?

磁感应与磁共振是目前最主要的两种无线充电技术,本文分析各种技术的优缺点。本文网络版地址:http://www.eepw.com.cn/article/145521.htm     

数据中心网络中的无线通信技术

文章认为将无线通信引入数据中心网络(DCN)是构建DCN的一种新选择,可以免除布线烦扰,从而方便维护无线节点;可以便捷地在服务器间建立链接,从而避免多跳传输额外代价;还可以动态改变DCN中的拓扑结构,有效减少"瓶颈"节点的流量。文章介绍了一种将无线通信与有线通信相结合来构建数据中心网络的新颖方法,并从物理构建和全局优化两个方面对相关新技术进行了分析。这些技术包括60GHz无线频段通信技术、3D波束成形、节点布置方法、基于遗传算法的信道分配等。通过这些技术的研究成果,可看出无线通信技术可大幅度提高数据中心网络性能,具有广阔的应用前景与理论研究价值。摘要:     

Smart-Aloha for Multi-Hop Wireless Networks

This paper presents a novel slotted ALOHA-based protocol for use in ad hoc networks where nodes are equipped with adaptive array smart antennas. The protocol relies on the ability of the antenna and DoA (Direction of Arrival) algorithms to identify the direction of transmitters and then beamform appropriately to maximize SINR (Signal to Interference and Noise Ratio) at the receiver. The performance of the protocol is evaluated using analytical modeling as well as detailed simulation in OPNET and Matlab where we demonstrate the benefits of using smart antennas. The impact of using different number of antenna elements is also studied for this environment.This work is funded by the NSF under grant ANIR-0125728.Harkirat Singh is a PhD candidate in Computer Science at Portland State University. He holds Master in Computer Science from Portland State University and B. E. in Electrical Engineering from Indian Institute of Technology (IIT), Roorkee, India. After his under graduation he joined Automation division of Siemens AG. He has research interests in next-generation TCP/IP networking, Mobile Wireless Computing, Ad-hoc networking, and low-power lost-cost sensor networks.Suresh Singh received his B. Tech. Degree in Computer Science from the Indian Institute of Technology (IIT) Kanpur in 1984 and his Ph.D. degree in 1990 from the University of Massachusetts at Amherst, both in Computer Science. His areas of research include energy-efficient protocols for wireless networking, sensor networks, cellular networking with a focus on 3g standards, and performance evaluation. His work has been funded by several federal agencies such as NSF, DARPA, and ONR and by a variety of industries. He is a member of the ACM and IEEE.     

Polarization Planning for Wireless Networks

Wireless Personal Communications - Polarization diversity enables frequency reuse in a telecommunication network. The most widely considered solution is to use two orthogonal polarizations on the...     

手机无线充电系统的设计与实现

设计了一种基于半桥式逆变技术和磁感应耦合技术的无线充电系统,整个系统由电源模块、整流滤波模块、高频逆变模块及分离式变压器4部分组成。采用多个初级线圈并联的方式为多个手机类负载同时供电,并通过分离式变压器线圈的优化设计提高了系统性能。测试结果表明该系统克服了采用单个初级线圈充电区域不足、各个设备充电效率低的缺点,减弱了待充电设备间的相互干扰,使其充电效率相当且都能获得基本恒定的电压,具有能量传输效果好、安全方便、成本低、适用范围广等优势。     

网络计费策略的研究

融合了蜂窝网、WLAN和MANET特点的混合网络日益受到关注,对关键技术的研究更是其发展的重要基础,而涉及到的计费策略更是研究的热点。运营商一直最关心计费问题,希望达到利益的最大化和最高的使用效率;而对于用户来说,最重要的是价格的可接受程度与所提供的服务质量（QoS）之间是否成正比。基于蜂窝网的计费策略、蜂窝网与WLAN的融合计费策略,提出了一种融合MANET的多跳蜂窝网的计费策略,它利用虚拟货币的概念和节点激励机制,同时考虑到安全因素,结合了密钥技术和数字签名技术。     

基于效用最大化的无线可充电传感器网络有向充电调度方案

针对当前无线可充电传感器网络(WRSNs)一对一移动充电方式存在充电效率低、定向充电模型缺乏问题,该文提出了一种基于充电效用最大化(MUC)的一对多有向充电调度方案。方案首先筛选网络中充电增益最大的有向覆盖子集;然后根据有向覆盖子集确定充电锚点,并进而规划充电器的移动路径;最后在满足移动充电器能量和充电周期约束条件下优...     

Strategies and Challenges for Interconnecting Wireless Mesh and Wireless Sensor Networks

Wireless sensor networks and wireless mesh networks are popular research subjects. The interconnection of both network types enables next-generation applications and creates new optimization opportunities. However, current single-gateway solutions are suboptimal, as they do not allow advanced interactions between sensor networks (WSNs) and mesh networks (WMNs). Therefore, in this article, challenges and opportunities for optimizing the WSN-WMN interconnection are determined. In addition, several alternative existing and new interconnection approaches are presented and compared. Furthermore, the interconnection of WSNs and WMNs is used to study challenges and solutions for future heterogeneous network environments. Finally, it is argued that the use of convergence layers and the development of adaptive network protocols is a promising approach to enable low end devices to participate in heterogeneous network architectures.     

基于效用最大化的无线可充电传感器网络有向充电调度方案

针对当前无线可充电传感器网络(WRSNs)一对一移动充电方式存在充电效率低、定向充电模型缺乏问题,该文提出了一种基于充电效用最大化(MUC)的一对多有向充电调度方案.方案首先筛选网络中充电增益最大的有向覆盖子集;然后根据有向覆盖子集确定充电锚点,并进而规划充电器的移动路径;最后在满足移动充电器能量和充电周期约束条件下优化移动充电器的充电时间.实验结果表明,该方案与平均能量充电(AEC)、固定能量充电(FEC)相比,充电效率分别提高了13.7%和32.7%;与最多节点覆盖(MNC)、最大平均增益覆盖(MAGC)子集筛选方案相比,充电效率分别提高了4.4%和35.9%;同时在网络饿死节点数目上与MNC, MAGC方案相比也显著降低.     

A Dedicated Multi-Chip Programmable System for Cellular Neural Networks

Cellular Neural Networks (CNN's) represent a remarkable improvement in the hardware implementation of Artificial Neural Networks (ANN's). In fact, their regular structure and their local connectivity feature contribute to render this class of neural networks especially appealing for VLSI implementations. CNNs are widely applied in several fields, including image processing and pattern recognition. In this research, the authors already presented two fully digitally programmable CNN chips with 3×3 (3×3DPCNN chip) and 6×6 cells (6×6DPCNN chip) respectively. In this paper, a system with twenty of the latter chips will be presented. The main features of this electronic system consist of the full digital programmability of the templates, the digital input/output for logic operations, the analog outputs for dynamic analysis and the implementation of space-variant as well as space-invariant CNNs.     

微型无线充电实验系统

本文开发了基于磁耦合谐振式的微型无线充电实验系统,并将其应用于本科实验教学.由于实验系统涵盖了无线电能传输理论与技术,以及电路、电磁场、模拟与数字电路和射频功率器件等理论与知识,通过本实验系统的教学,既提高了本科生综合应用基础理论知识解决实际问题的能力,又加深了他们对新知识和新原理的理解.