支持OAI-PMH的元数据互操作体系结构设计与实现

随着全球数字图书馆的迅猛发展,互操作成为亟待解决的重要问题。OAI-PMH协议的制定为在元数据级别上设计实现一个统一、高效的互操作框架创造了条件。文章基于北京大学数字图书馆项目,详尽阐述了一个典型的支持OAI-PMH互操作体系结构的完整的设计与实现;不仅包括在理论上逻辑清晰的设计方案,在实现上也采用了比较成熟又兼具理论和应用前景的技术,如Java、DOM、XML、Oracle9i等。该文的工作为将来联合式数字图书馆这一发展方向做出了很好的尝试。     

Real-time collision-free motion planning of a mobile robot using a Neural Dynamics-based approach

A neural dynamics based approach is proposed for real-time motion planning with obstacle avoidance of a mobile robot in a nonstationary environment. The dynamics of each neuron in the topologically organized neural network is characterized by a shunting equation or an additive equation. The real-time collision-free robot motion is planned through the dynamic neural activity landscape of the neural network without any learning procedures and without any local collision-checking procedures at each step of the robot movement. Therefore the model algorithm is computationally simple. There are only local connections among neurons. The computational complexity linearly depends on the neural network size. The stability of the proposed neural network system is proved by qualitative analysis and a Lyapunov stability theory. The effectiveness and efficiency of the proposed approach are demonstrated through simulation studies.     

Data Communications for Internet Robots

For Internet robots, the most challenging and distinct difficulties are well recognized to be associated with Internet transmission delays, delay jitter and not-guaranteed bandwidth, which might degrade system performance dramatically or even lead to instability. Current approaches to data communication between the remote robot and the human operator employ directly one of the two currently available protocols, i.e. TCP and UPD. In this paper, a teleoperation-oriented data transmission mechanism is implemented. Compared to TCP, the presented scheme provides minimized transmission delays and delay jitter; in the steady state, its transmission rate is much smoother; when available network bandwidth changes, it adapts to the variation quickly without large overshoot. Compared to UDP, it is inter-protocol fairness convergent, intro-protocol convergent, and efficient convergent. The presented mechanism is deployed in a mobile robot teleoperation system developed. In the experiments, users successfully guided a Pioneer-2 mobile robot through a laboratory environment remotely over the Internet via a web browser.     

计算机光学乐谱识别技术

计算机光学乐谱识别是计算机技术在音乐领域的发展和应用，主要利用图像处理，模式识别，文档图像分析等相关技术，把乐谱图像转化成通用的数字音乐格式，OMR实现传统乐谱数字化，在计算机音乐、计算机辅助音乐教学，数学音乐图书馆等众多领域有着广泛的应用前景，OMR包括乐谱图像预处理，谱线检测与删除，原始音符对象识别和特征音符对象解释与重组等主要过程，音符对象的识别，解释与重组是其中的难点和关键。     

基于VB的监控系统软件接口研究

文章介绍了一个实际工程应用中等离子体表面处理监控系统上位机软件接口的编程方法。为了满足系统需求,利用VB、Matlab混合编程,实现了对Access数据库数据的存储和调用,绘出多窗口显示曲线,并完成了从Excel调用实验数据进行曲线拟合。     

基于Web的数控加工几何仿真系统研究

论文提出了基于Web的数控加工几何仿真系统体系结构,该体系结构具有可扩展性、交互性、动态性,能够很好地满足基于Web的数控加工几何仿真的要求,并以数控弯管过程为例,采用VRML、J2EE技术,实现了一个远程数控弯管几何仿真系统,证明了这种体系结构是可行而有效的。     

一种IP网视频单播传输中的拥塞控制方法

文章提出了一种基于RTP/RTCP的单播拥塞控制算法,该算法具有较好的稳定性和TCP友好性。     

沥青混凝土自动摊铺机监控系统软件设计

针对LTU125A沥青混凝土自动摊铺机项目的技术要求,介绍了自动摊铺机监控系统中显示、键盘和通讯模块的软件设计方法。     

A New Grade Carbon Black Produced by Thermal Plasma Process

This paper presents a new route about producing carbon black,by wich the natural gas cracking is carried out in the absence of oxygen thanks to an electric energy supply externally given by a plasma jet.The carbon black produced by this process has a narrow size distribution and a small average diameter of 38nm as well as a highly branched aggregate.The higher DBP value of 1.40ml/g shows it should be a high structure carbon black.The FTIR spectra shows that there are lots of aromatic c-c bonds and a large amount of nitrogen-coutaining functional groups on the carbon blacks surface,such as-NH,-CN as we3ll as -CH,-OH,-COOH groups.     

利用Mediva在Delphi环境下实时实现回转窑调窑参数模糊优化

该文以开发中国长城铝业公司氧化铝厂2#回转窑调窑参数模糊优化软件为例,介绍了利用Mediva在Delphi环境下实时实现回转窑调窑参数模糊优化的具体步骤和方法。该技术将Matlab卓越的科学计算能力和Delphi强大的系统开发能力相结合,大大缩短了系统的开发周期,通过改写利用Mediva编译M文件后生成的CPP文件,实现了数据在应用程序之间的传递,通过在VC6.0中创建DLL文件,实现了代码的封装,提高了系统的安全性与可靠性,且程序的运行脱离了Matlab环境,大大提高了运行速度。