无线传感器网络中移动sink节点的路径规划

在无线传感器网络中,大量感知数据汇集到sink节点的采集方法会导致sink节点附近的节点能量耗尽,造成能量空洞。针对该问题,利用移动的sink节点进行数据收集是一种解决方法,其中移动sink的路径规划成为一个重要的问题。提出了一个移动sink路径规划算法,将无线传感器中随机分布的节点划分为不同的子区域,寻找sink节点移动的最佳转向点,最终得到最优的移动路径,以实现无线传感器网络生命周期最大化。仿真实验表明,与现有方案相比,该算法能显著延长网络的生命周期。     

Soret and Dufour effects between two rectangular plane walls with heat source/sink

This study addresses the thermo‐diffusion and the diffusion‐thermo phenomena in a semi‐infinite absorbent channel whose walls are contracting/expanding, with heat source/sink effects. The governing partial differential equations with suitable boundary conditions are transformed to a system of dimensionless ordinary differential equations. An analytic solution of the problem has been found using a technique called homotopy analysis method (HAM). HAM gives consistently valid answers to the problem over an extensive variety of parameters and also provides better accuracy. To validate the analytical results, a comparison has been presented with a numerical solution calculated by using the parallel shooting method. The effects of dimensionless parameters, that is, deformation parameter, Reynolds number, Soret and Dufour numbers, and heat source/sink parameter on the expressions of velocity, temperature, and concentration profiles are analyzed graphically to understand the physics of the deformable channel. It has been noted that the velocity across the channel is higher for the expanding channel, as compared to that for the contracting channel. Also the Soret and Dufour number increases the temperature of the fluid, and decreases the concentration. The temperature profile has an increasing behavior in the case of heat source, and a decreasing behavior in the case of heat sink.     

Model Selection for Unsupervised Learning of Visual Context

This study addresses the problem of choosing the most suitable probabilistic model selection criterion for unsupervised learning of visual context of a dynamic scene using mixture models. A rectified Bayesian Information Criterion (BICr) and a Completed Likelihood Akaike’s Information Criterion (CL-AIC) are formulated to estimate the optimal model order (complexity) for a given visual scene. Both criteria are designed to overcome poor model selection by existing popular criteria when the data sample size varies from small to large and the true mixture distribution kernel functions differ from the assumed ones. Extensive experiments on learning visual context for dynamic scene modelling are carried out to demonstrate the effectiveness of BICr and CL-AIC, compared to that of existing popular model selection criteria including BIC, AIC and Integrated Completed Likelihood (ICL). Our study suggests that for learning visual context using a mixture model, BICr is the most appropriate criterion given sparse data, while CL-AIC should be chosen given moderate or large data sample sizes.     

IP网络上电路倍增设备的研究

简要介绍了通过IP网络上电路倍增设备(IP CME)的数据流的处理过程;IP CME中的复用技术;控制IP包发送的激活算法;网络发生拥塞丢包的处理方法;并在传输效率和信令处理2个方面与VOIP进行比较,可以看出IP CME具有很大的优越性和良好的发展前景。     

一种新颖的基于非压缩数字视频的水印盲检测算法

数字水印是一种嵌入到多媒体数据中用来进行版权标识的工具。在众多的宿主媒体中，数字视频因具有隐藏容量大、透明性好、鲁棒性强等诸多优点而受到日益广泛的关注。但是很多文献中提到的视频水印都是从数据流中提取单帧图像进行处理，这类算法与静态图像的水印方法如出一辙，没有充分利用视频文件的各种特性。而且对帧平均、视频压缩等常见的运动图像攻击方法十分敏感。针对这些问题，本文以非压缩视频文件为实验对象，结合人类视觉模型和彩色图像场景分割的方法，提出并实现了一种基于视频时间轴的数字水印盲检测算法。实验结果表明算法有效实用。     

超宽带极窄脉冲设计与产生

超宽带(UWB)技术是以持续时间极短的脉冲作为传输载体进行数据通信的无线新技术。基于BJT雪崩特性,本文采用并行同时触发的工作方式,设计并产生了高重复速率的UWB脉冲电路发生器,极大地减少了时延,缩短了上升时间,提高了脉冲的幅度,并从等效电路法的观点分析计算了脉冲的特性参数,理论结果与实测结果具有较好的一致性。     

In flight MTF monitoring and compensation for CCD camera on CBERS-02

All image systems cause a blurring of the scene radiance field during image acquisi- tion. Accurate characterization of this blurring is referred to as the modulation transfer function (MTF)[1]. The MTF is a fundamental imaging system design specification and system quality metric often used in remote sensing. It results from the cumulative effects of the instrumental optics (diffraction, aberrations, focusing error), integration on a pho- tosensitive surface, charge diffusion along the arra…     

空气中烧成的镍导体及其应用

将空气中烧成的镍导体用于散热制冷片制作工艺中，可降低成本，提高合格率。通过实验得到的最佳值为：镍导体中４号玻璃（ＳｉＯ２＞３０，Ｂ２Ｏ３＞１０，ＰｂＯ＜５５，ＴｉＯ２少许）的含量４．５％，化学镀镍时间５０ｍｉｎ，方阻４７．５ｍΩ／□，附着力８．１Ｎ／ｍｍ２。     

景像匹配区中稳定景物的分割方法研究

研究了景像匹配区中稳定景物的分割方法———强度和法及分形常数法 ,成功地分割了匹配区中的稳定景物 ,为评价区配区景物稳定性提供了依据 .其中分形常数法是分形理论应用在图像分割领域的一个新尝试