CAVE系统中不规则多屏投影变换矩阵

常见的CAVE系统是由4个正方形投影面构成一个立体空间,将复杂的数据以可视化的方式展现,营造一个逼真的虚拟环境,带给用户一种非凡的沉浸式体验。本文在分析投影变换矩阵的基础上,通过构建CAVE投影坐标系,提出构建不规则投影变换矩阵的快速计算方法。该方法使CAVE系统不再局限于标准的立方体空间,并通过获取用户在CAVE投影坐标系下的坐标位置,实时计算投影变换矩阵,满足用户在任意空间位置下的最佳观测视角。     

非整数阶系统频域辨识的递推最小二乘算法

非整数阶系统辨识方法是建立非整数阶系统模型的一种重要工具．本文提出了一种非整数阶系统频域辨识的最小二乘递推算法．给出了算法的详细推导，并用已知系统验证了算法的有效性．结果表明该算法是整数阶系统辨识的最小二乘递推算法的推广．使用此算法，不但能辨识整数阶系统，还能辨识非整数阶系统．     

蚁群系统模型的比较及参数优化

蚁群算法是一种模拟进化算法，根据信息素更新策略的不同，蚁群系统模型分为蚁密系统、蚁量系统和蚁周系统。本文对三种模型的原理、特点进行研究，并通过仿真实验分析三种模型的性能及参数对其性能的影响，进而提出的参数优化规则，有利于蚁群算法在组合优化问题中的推广和应用。     

用小型PLC-FP1实现物料自动分拣系统控制

本文介绍如何利用日本松下电工生产的一种小型PLC—FPl，实现物料自动分拣系统控制及梯形图编程．本系统在实践中性能更加稳定，大大降低了故障率．取得了满意的结果，在中小型企业中具有较高推广价值．     

新型智能车辆监控调度系统

本文主要介绍一种民用机场新型智能车辆调度指挥系统的原理及系统组成，系统运行测试结果情况表明了该系统是成功的，并具有很好的扩展性和推广意义。     

基于TS模型的二型模糊控制器和观测器分析与设计

主要探讨一种新的系统方法——二型模糊系统在控制上的应用．文章先介绍了二型模糊集合和系统的基本概念和基本方法，然后集中推导TS模型下规则的输出形式，推广一型系统的特性，从而获得二型模糊控制器和观测器的表达式、稳定性以及其它特性分析方法，并以小车倒立摆仿真验证．最后文章从整体上分析和比较了传统系统、一型模糊系统和二型模糊系统的主要特点和不同点．     

一种新型网络化数字视频实时监控系统

介绍了一种新型网络化数字视频实时监控系统。该系统以基于嵌入式处理器和嵌入式实时操作系统VxWorks的MPEG-4网络硬盘录像机为前端测控装置．通过TCP／IP通信端口接入二级宽带局域网．将摄像机采集的模拟视频信号处理转换为MPEG4格式的IP数据流后直接发送给网上的PC机．PC机可以利用应用软件或IE浏览器实时预览视频图像。叙述了监控系统的硬件结构、软件功能结构，并给出了该系统在军事仓库群的网络视频监控中的实用效果和可推广的场合。     

用小型PLC-FP1实现物料自动分拣系统控制

本文介绍如何利用日本松下电工生产的一种小型PLC-FP1．实现物抖自动分拣系统控制及梯形图编程。本系统在实践中性能更加稳定，大大降低了故障率，取得了满意的结果，在中小型企业中具有较高的推广价值。     

推广卡尔曼滤波算法在航位推算系统中的应用

给出了航位推算系统的设计方法并研究了它螺仪的特性，在建立起该系统的非线性数学模型的基础上，提出了一种非线性推广卡尔曼滤波算法。试验结果表明，该系统具有良好的导航与定位性能。     

铁路信号电缆绝缘在线测试

数字绝缘表通常只能对离线电缆进行绝缘测试。介绍了一种在线电缆绝缘测试系统，解决了测试干扰、设备互容等关键技术，这一设备已应用在TJWX型信号微机监测系统中，并在铁路信号系统大量推广。     

PCCAVE:基于连网PC的廉价CAVE系统

讨论了一个基于 PC的廉价 CAVE系统的实现方法 .FCCAVE使用 4台微机配合中低档的图形显示卡构成图形绘制系统 ,代替 SGI工作站和 Reality Engine高档工作站图形卡 .PCCAVE整体上是一个主从式并行计算结构 ,主节点提供人机交互控制接口 ,从节点接受主节点命令和绘制立体图像 .PCCAVE的通信子系统使用 MPI实现 ,实现了并行计算的同步控制和智能信息代理服务 ,图形子系统以 Direct X和 Open GL 作为底层图形 API.还研究了系统的主要瓶颈和性能指标 .利用该系统实现了浙江大学的校园漫游 .结果表明该系统的许多指标都超越或者接近于 SGI Onyx2 ,具有良好的推广前景和较高的实用价值 .     

3DIVE: An Immersive Environment for Interactive Volume Data Exploration

This paper describes an immersive system,called 3DIVE,for interactive volume data visualization and exploration inside the CAVE virtual environment.Combining interactive volume rendering and virtual reality provides a netural immersive environment for volumetric data visualization.More advanced data exploration operations,such as object level data manipulation,simulation and analysis ,are supported in 3DIVE by several new techniques,In particular,volume primitives and texture regions ae used for the rendering,manipulation,and collision detection of volumetric objects;and the region-based rendering pipeline is integrated with 3D image filters to provide an image-based mechanism for interactive transfer function design.The system has been recently released as public domain software for CAVE/ImmersaDesk users,and is currently being actively used by various scientific and biomedical visualization projects.     

Modeling and performance analysis using extended fuzzy-timing Petrinets for networked virtual environments

Despite their attractive properties, networked virtual environments (net-VEs) are notoriously difficult to design, implement, and test due to the concurrency, real-time and networking features in these systems. Net-VEs demand high quality-of-service (QoS) requirements on the network to maintain natural and real-time interactions among users. The current practice for net-VE design is basically trial and error, empirical, and totally lacks formal methods. This paper proposes to apply a Petri net formal modeling technique to a net-VE-NICE (narrative immersive constructionist/collaborative environment), predict the net-VE performance based on simulation, and improve the net-VE performance. NICE is essentially a network of collaborative virtual reality systems called the CAVE-(CAVE automatic virtual environment). First, we introduce extended fuzzy-timing Petri net (EFTN) modeling and analysis techniques. Then, we present EFTN models of the CAVE, NICE, and transport layer protocol used in NICE: transmission control protocol (TCP). We show the possibility analysis based on the EFTN model for the CAVE. Then, by using these models and design/CPN as the simulation tool, we conducted various simulations to study real-time behavior, network effects and performance (latencies and jitters) of NICE. Our simulation results are consistent with experimental data.     

基于椭圆曲线密码体制的CDMA网络鉴权设计

由于我国并未掌握蜂窝鉴权与话音加密算法（CAVE）的实现,使得CDMA网络并未实现真正的安全。提出了一种基于椭圆曲线的CDMA网络鉴权方案,通过公钥签名机制完成对用户身份的识别和管理。与CAVE算法相比,该方案除具备自主知识产权外,还减轻了鉴权中心的负担。最后通过实验证明这种鉴权方案是完全可行的。     

CAVE and fishtank virtual-reality displays: a qualitative and quantitative comparison

We present the results from a qualitative and quantitative user study comparing fishtank virtual-reality (VR) and CAVE displays. The results of the qualitative study show that users preferred the fishtank VR display to the CAVE system for our scientific visualization application because of perceived higher resolution, brightness and crispness of imagery, and comfort of use. The results of the quantitative study show that users performed an abstract visual search task significantly more quickly and more accurately on the fishtank VR display system than in the CAVE. The same study also showed that visual context had no significant effect on task performance for either of the platforms. We suggest that fishtank VR displays are more effective than CAVEs for applications in which the task occurs outside the user's reference frame, the user views and manipulates the virtual world from the outside in, and the size of the virtual object that the user interacts with is smaller than the user's body and fits into the fishtank VR display. The results of both studies support this proposition.     

A Flexible Architecture for Virtual Humans in Networked Collaborative Virtual Environments

Complex virtual human representation provides more natural interaction and communication among participants in networked virtual environments, hence it is expected to increase the sense of being together within the same virtual world. We present a flexible framework for the integration of virtual humans in networked collaborative virtual environments. A modular architecture allows flexible representation and control of the virtual humans, whether they are controlled by a physical user using all sorts of tracking and other devices, or by an intelligent control program turning them into autonomous actors. The modularity of the system allows for fairly easy extensions and integration with new techniques making it interesting also as a testbed for various domains from “classic” VR to psychological experiments. We present results in terms of functionalities, example applications and measurements of performance and network traffic with an increasing number of participants in the simulation.     

虚拟计算环境中的虚拟网络

虚拟计算环境是近年来的学术研究热点,而虚拟网络是构成虚拟计算环境的核心技术。本文介绍了主流的虚拟网络构成原理和虚拟网络实现技术,分析了虚拟计算环境中虚拟网络的特点,总结并提出了虚拟网络的性能开销、QoS、自适应和安全性等开放性问题。     

Mining of mixed data with application to catalog marketing

Clustering is one of the most popular techniques in data mining. The goal of clustering is to identify distinct groups in a dataset. Many clustering algorithms have been published so far, but often limited to numeric or categorical data. However, most real world data are mixed, numeric and categorical. In this paper, we propose a clustering algorithm CAVE which is based on variance and entropy, and is capable of mining mixed data. The variance is used to measure the similarity of the numeric part of the data. To express the similarity between categorical values, distance hierarchy has been proposed. Accordingly, the similarity of the categorical part is measured based on entropy weighted by the distances in the hierarchies. A new validity index for evaluating the clustering results has also been proposed. The effectiveness of CAVE is demonstrated by a series of experiments on synthetic and real datasets in comparison with that of several traditional clustering algorithms. An application of mining a mixed dataset for customer segmentation and catalog marketing is also presented.     

面向服务网格的虚拟环境部署运行管理系统

虚拟技术的最新进展为网格计算提供了封装资源的新方式,其封装性、隔离性和安全性能够有效屏蔽底层资源的异构性,根据用户应用需求定制执行环境,更好地适应于网格环境的复杂性和应用的多样性。为了满足当前服务网格的需求发展,基于新的虚拟机技术,研究适合于服务网格的虚拟环境部署运行管理系统,该系统为用户提供可视化、易操作的远程虚拟环境部署和运行管理功能;并实现一个标准的网格服务,结合服务网格平台CROWN,该服务可根据用户应用的特定需求动态透明地部署虚拟执行环境,并根据资源状态自适配调度执行用户任务。并对系统进行了实验分析,实验结果验证了系统的良好可用性和运行性能。