大体积混凝土全数字化温度监测系统

本文针对大体积混凝土水化热过程中的温度监测要求提出一种全数字化测温系统。该系统能及时监测大体积混凝土内部温度变化和各测点之间温差等信息并以报表、图形、曲线等方式向用户显示,从而指导保养工作、确保工程质量。该系统还对采集的数据进行处理、分析;并可按照用户需求自动生成相应的报表、曲线。     

TCP over卫星的拥塞控制及跳动窗口算法

本文分析了现有的多种基于无线卫星链路的TCP拥塞控制改进协议．并在此基础之上提出了一种适于卫星链路的TCP拥塞控制跳动窗口算法．此算法的优点主要体现在：减少了发送方不必要的确认信息，不仅克服了Go-backn算法的缺点．而且极大地避免了数据的浪费重传，提高了通信效率，减轻了卫星通信负担，并具有灵活性和易控性等特点、接着介绍了此拥塞控制算法在基于“北斗一号”卫星数字报文通信的西部“数字油田”建设中的文件传输系统的实现和应用．并说明了文件传输系统的特点，列出了此系统的设计流程图．给出了此算法在流程图中的应用位置。研究此算法不仅对基于卫星的互联网发展具有推动作用，而且对我国自主的卫星通信事业的发展具有很大帮助。此算法在应用中取得了很好的效果。     

Animating visible speech and facial expressions

We present four techniques for modeling and animating faces starting from a set of morph targets. The first technique involves obtaining parameters to control individual facial components and learning the mapping from one type of parameter to another through machine learning techniques. The second technique is to fuse visible speech and facial expressions in the lower part of a face. The third technique combines coarticulation rules and kernel smoothing techniques. Finally, a new 3D tongue model with flexible and intuitive skeleton controls is presented. The results of eight animated character models demonstrate that these techniques are powerful and effective.     

Modeling two-windows TCP behavior in differentiated services networks

Two important issues in assured services within differentiated services architecture are bandwidth guarantee and fair sharing of unsubscribed bandwidth among TCP flows with and without bandwidth reservations. Although the subscribed bandwidth can be guaranteed by increasing network capacity or deploying strict admission control mechanisms, the costs of such solutions are very high. The issue of fair sharing of excess bandwidth is also not well solved. To address those issues, a modified TCP, named two-windows TCP, has been proposed. The performance of the protocol is evaluated by simulations. But its effectiveness is not validated theoretically under general network conditions, which is important for understanding the benefits and costs of using the protocol. In this paper, an analytical model is developed for the purpose. The model characterizes throughput of individual two-windows TCP flow as a function of contract rate, round trip time, loss rates of In and Out packets. Extensive simulations validate the analytical model. It's shown two-windows TCP is effective not only on solving the issues of bandwidth guarantee and fair sharing of unsubscribed bandwidth, but also on increasing the utilization of bottleneck link bandwidth. Moreover, its performance is robust to network conditions, which is important for wide deployment over Internet.     

Facial expression recognition using constructive feedforward neural networks

A new technique for facial expression recognition is proposed, which uses the two-dimensional (2D) discrete cosine transform (DCT) over the entire face image as a feature detector and a constructive one-hidden-layer feedforward neural network as a facial expression classifier. An input-side pruning technique, proposed previously by the authors, is also incorporated into the constructive learning process to reduce the network size without sacrificing the performance of the resulting network. The proposed technique is applied to a database consisting of images of 60 men, each having five facial expression images (neutral, smile, anger, sadness, and surprise). Images of 40 men are used for network training, and the remaining images of 20 men are used for generalization and testing. Confusion matrices calculated in both network training and generalization for four facial expressions (smile, anger, sadness, and surprise) are used to evaluate the performance of the trained network. It is demonstrated that the best recognition rates are 100% and 93.75% (without rejection), for the training and generalizing images, respectively. Furthermore, the input-side weights of the constructed network are reduced by approximately 30% using our pruning method. In comparison with the fixed structure back propagation-based recognition methods in the literature, the proposed technique constructs one-hidden-layer feedforward neural network with fewer number of hidden units and weights, while simultaneously provide improved generalization and recognition performance capabilities.     

Design a progressive video caching policy for video proxy servers

Proxy servers have been used to cache web objects to alleviate the load of the web servers and to reduce network congestion on the Internet. In this paper, a central video server is connected to a proxy server via wide area networks (WANs) and the proxy server can reach many clients via local area networks (LANs). We assume a video can be either entirely or partially cached in the proxy to reduce WAN bandwidth consumption. Since the storage space and the sustained disk I/O bandwidth are limited resources in the proxy, how to efficiently utilize these resources to maximize the WAN bandwidth reduction is an important issue. We design a progressive video caching policy in which each video can be cached at several levels corresponding to cached data sizes and required WAN bandwidths. For a video, the proxy server determines to cache a smaller amount of data at a lower level or to gradually accumulate more data to reach a higher level. The proposed progressive caching policy allows the proxy to adjust caching amount for each video based on its resource condition and the user access pattern. We investigate the scenarios in which the access pattern is priorly known or unknown and the effectiveness of the caching policy is evaluated.     

电站机组瞬态过程性能监测初探

建立了汽轮机系统的瞬态数学模型和电厂主要经济性能指标详细计算模型 ,与已有的锅炉动态数学模型组成电厂主要瞬态性能数学模型 ;应用连接策略将模型各模块连接为整体 ;针对某 2 0 0MW机组 ,进行了给水流量减少 5 % ,燃料量减少 2 6 %时机组瞬态经济性能的计算 ,并对计算结果进行了分析。从而为进一步得到在各种工况下 ,包括工况变动幅度较大时机组较准确的性能分析奠定了基础     

最大限度地发挥国产优秀影片的功效

以“三个代表”重要思想为指导 ,用优秀的影视作品占领军营思想文化阵地 ,是部队影视发行放映工作必须始终遵循的原则。江泽民同志在十六大报告中指出 :全面建设小康社会 ,必须大力发展社会主义文化 ,建设社会精神文明。当今世界 ,文化、经济和政治相互交融 ,在综合国力竞争中的地位和作用越来越突出……全党同志要深刻认识文化建设的战略意义 ,推动社会主义文化的发展繁荣。艺术的民族性是民族文化意识的反映 ,民族文化具有极为强烈的感召力 ,因而也为群众所喜闻乐见。优秀国产电影作为中华民族文化的重要内容 ,历来受到国家的保护和扶植。…     

自适应挤压油膜阻尼器支承的转子系统稳态动力特性研究

首先对带有挤压油膜阻尼器(SFD)和金属橡胶外环的自适应挤压油膜阻尼器(ASFD/MRR)的刚性转子系统的稳态振动特性进行了对比研究,理论和实验研究表明与SFD相比,ASFD/MRR具有更好的减振性能,尤其在大不平衡量时能有效地抑制非线性振动的发生并保持良好的减振效果.本文对带有ASFD/MRR的刚性转子系统的稳态响应的影响因素进行了研究,为ASFD/MRR在工程转子支承上的应用,提供了可靠的依据.     

多通道噪声和振动测试分析系统

设计了一个利用DSP系统、USB接口和笔记本电脑,实现对机械噪声和振动进行多通道数据采集与分析处理的系统,克服了常用的单一信号分析的不足.通过设计DSP信号测试分析软件,实现了实时机械状态监测与故障诊断,使用十分方便.