固网智能化创新业务的研究

固网智能化为PSTN提供丰富业务创造了条件,能进一步挖潜PSTN的潜力,为PSTN赋予了新的活力.本文提出三个固网智能化创新业务:多号彩振、电话广告和变声业务,并在其业务定义、业务功能、技术实现方案、产品定位与目标用户等方面进行了研究.     

基于JRobin的网络性能监控管理

网络性能监控管理是整个计算机网络管理中的一个重要环节,RRDtool作为一种强大的数据存储工具,已在网络性能监控系统中得到广泛应用。针对基于Java开发的网管系统,以纯Java实现的JRobin是RRDtool最好的替代方案,文章在引入JRobin的基础之上,实现了一个基于JRobin的网络性能监控管理系统,并对系统功能做了详细描述。     

GTD model-based time-shift invariant target identification using matching pursuits and likelihood ratio tests

In order to improve the identification capability of ultra wide-band radar, this paper introduces a step-variant multiresolution approach for the time-shift parameter estimation. Subsequently, combining with the approach, a Geometrical Theory of Diffraction （GTD） model-based time-shift Invariant method to target identification using Matching Pursuits and Likelihood Ratio Test （IMPLRT） is developed. Simulation results using measured scattering signatures of two targets in an ultra wide-band chamber are presented contrasting the performance of the IMPLRT to the Wang＇s MPLRT technique.     

三电平逆变器直接转矩控制仿真分析

对三电平逆变器直接转矩控制的基本原理,拓扑结构,控制原理,及控制策略进行了详细的分析,给出了一种结合三电平特性的异步电机数学模型,通过仿真验证了建立在该模型下的中点钳位式三电平逆变器直接转矩控制的良好动静态特性.     

PSHO-HF-PM: An Efficient Proactive Spectrum Handover Mechanism in Cognitive Radio Networks

In the paper, we develop an efficient proactive spectrum handover mechanism by using packet scheduling algorithm, called PSHO-HF-PM, to reduce unusable channel. It effectively integrates several mechanisms (hole filling and packet migration) to reduce the bandwidth fragment and support QoS. Its basic idea is in that a new packet is scheduled by migrating some packets to other channels if none of holes in any channels can accommodate it; otherwise repeating the above processes after random waiting time. Meanwhile under an effective data structure, such as the balanced binary search tree, its computational complexity will be \(O(2n\log n)\) at most. In the proposed packet scheduling algorithm, packet migration plays a key role in the improvement of bandwidth efficiency and QoS. We also evaluate the performance of total service time for proactive spectrum handover mechanism based on a Preemptive Resume Priority M/G/1 queuing network model. The performance analysis and simulation results show that it performs much better than other proactive and reactive handover mechanism in collision rate, total service time, packet loss probability and bandwidth fragment ratio.     

基于多尺度特征表示的城市道路检测

基于图像的车辆周边场景分析是近来车辆主动安全的热门研究方向,但对于复杂路况的道路识别目前依然是一个难题。该文提出一种适用于城市复杂道路场景的单目视觉路面识别算法。该方法结合多尺度的稀疏编码,在大尺度上利用道路的局部纹理信息,在较小尺度,特别是中等尺度上利用空间上下文信息,对车辆的可行驶区域进行识别。实验表明,该方法提高了道路与周边环境中相似纹理的区分能力;在铺设良好的结构化道路,或者车道线、路界缺失,光照复杂的道路场景中,该方法都取得了较好的检测结果。     

正负母线均压变换器拓扑电路的设计

本文设计的变换器电路能够在提供辅助电源的同时在硬件上保证母线的平衡。变换器采用单端反激的设计方法,正负母线均衡通过二极管钳位来完成的。本文对拓扑电路的设计方案和变压器等参数进行了详细的描述和计算。实测电路能提供60W的辅助电源能力,正负母线不均衡度为1.8V。此种拓扑电路可以应用在任何母线为±(260-450)V的开关电源上。     

P2P和CDN技术融合实现流媒体业务

P2P和CDN融合实现流媒体业务是一种高效实用的方案。本文首先对P2P和CDN技术的优缺点进行分析比较,指出二者融合的优势,然后介绍并分析了P2P和现有CDN融合实现流媒体业务的几种解决方案,并分别描述了各自的优缺点,最后提出一种适合运营商网络现状的P2PCDN流媒体方案建议。     

mWSN for Large Scale Mobile Sensing

This paper reviews the state-of-the-art features introduced by sink mobility into wireless sensor networks (WSN), and introduces the architecture of mobile enabled Wireless Sensor Network (mWSN) to realize large-scale information gathering via networked wireless sensors and mobile sinks. After introducing the mobile sensing scenarios, some fundamental design parameters in mWSN have been investigated, such as cluster size, sink velocity, transmission range, and packet length. Our contributions include: (1) A cluster formation method has been proposed via multihop forwarding to form a cluster around the expected position of a mobile sink, in order to guarantee packet delay and minimize energy consumption. (2) Analysis of the performance influence by sink mobility leads to the conclusion that the optimal sink velocity must make a compromise between sink-sensor meeting delay and message delivery delay. (3) Finding that large transmission range and short packet length are both of benefit to lower the outage probability of packet transmission. Extensive simulations have been designed to evaluate the performance of mWSN in terms of packet delay, energy consumption and outage probability of packet transmission.

低压PLC信号自动增益放大接收电路没计

文中在分析L-PLC系统特点和自动增益AGC控制电路工作原理的基础上,设计了一种具有高信噪比、低失真和宽动态范围的自增益控制电路.着重阐明了该电路的硬件设计,并给出了重要参数的设计公式.