旋转体圆周角位置控制方法

针对旋转导向钻井工具稳定平台的角位置姿态控制系统,分析了角位置系统控制中圆周旋转运动各动 态参数之间的关系和旋转角度控制的特点．介绍了满足这类特殊控制要求的控制算法．提出一种在极坐标系中描述 动态响应曲线的方法,非常适用于旋转角位置控制系统．设计了一个钻井工具稳定平台模糊控制系统,它以角位置 和角速度为输入、以控制电流的增量为输出,不仅可以解决角位置与旋转方向间的关系问题,而且具有比常规控制 方法更好的鲁棒性及抗干扰能力,因此也更适合于钻井工程中的井下工作环境．     

基于VRML的倒立摆三维仿真

传统方法分析动态系统抽象而且繁琐,本文利用虚拟现实技术的编辑系统VrmlPad和软件平台VRML语言,建立倒立摆的三雏虚拟场景。通过Matlab的虚拟现实工具箱将虚拟倒立摆的三维场景与Simulink中倒立摆的仿真模型连接起来,采用PID算法对倒立摆进行控制,实验结果实现了逼真的可视化和交互性仿真。整个设计分析过程较传统方法直观。     

三维机械虚拟模型库的研究

提出了机械零部件三维模型库的构建思路与方法,介绍了三维建模、虚拟现实、数据库及网络技术。通过虚拟现实技术和网络技术实现了三维模型在网络上的传播及用户对三维模型的旋转、平移、放大、及缩小等实时交互操作。     

基于OpenGL的钻井三维场景动态仿真

为能在脱离钻井现场的情况下向学员展示钻井操作的工艺流程,开发基于OpenGL的钻井三维场景仿真系统．利用3DSMAX构造复杂的钻井设备模型;在OpenGL平台中调用该模型,并利用双缓存技术控制各三维模型在场景中平滑的运动,实现钻井三维场景的动态仿真．该系统可以逼真地仿真正常钻进、起下钻、卸扣和上卡等多种钻井工艺流程．     

可视化协同导向钻井虚拟环境

针对传统导向钻井技术中信息展示方式和工作方式的不足,基于虚拟现实、CSCW和Agent等技术构建一个可视化协同导向钻井虚拟环境,为不同地点的钻井技术人员和专家提供协同工作平台,提高了钻井效率。描述虚拟环境的体系结构及其主要技术,包括钻井对象三维可视化、服务器与客户端的通信、协作成员的管理和多用户并发控制。     

基于虚拟现实技术的钻井仿真系统设计

针对基于三维动画和OpenGL技术的钻井仿真系统存在画面沉浸感不强、交互性差等不足,开发了基于虚拟现实技术钻井仿真系统。在对钻井过程进行数学建模的基础上,设计了模型计算软件,该软件逼真地再现了钻井现场参数的变化情况。利用3D MAX建模软件构建了复杂的钻井设备模型,并在Virtools平台下利用行为模块控制各模型独立的运动,实现了动态的钻井虚拟场景。该场景在硬件平台的配合下,能够逼真地再现钻进、起下钻、接单根、上扣、卸扣等几十种钻井工艺流程。该系统的实现为油田安全作业的培训提供了一条新的途径,具有一定推广价值。     

Virtools中插值算法的研究与应用

在虚拟现实系统开发中有很多对象是需要通过旋转的方法实现运动的,利用插值算法实现物体的旋转是很常用的方法,该文阐述了旋转算法和双线性插值算法的原理和实现方法。旋转算法是根据三维物体绕三个坐标轴旋转的角度及先后顺序,依据三个运算公式计算得到一个旋转轴和旋转角度,再根据该旋转轴和旋转角度对物体实施旋转。双线性插值算法其速度慢,但得到的图像纹理清晰,能满足大多数程序的要求。这两种方法可以处理不同的旋转物体。文中同时给出了使用Virtools图形开发引擎应用这两种算法来解决钻井模拟仿真系统中的物体旋转的方法。最后可以发现整个系统实现了预想的旋转效果,并且旋转精度也在可控制的范围内,满足了系统真实性的要求。     

基于Maya和Virtools虚拟现实三维建筑模型建模技术

为创建三维建筑动态视景以及为用户提供沉浸式虚拟环境体验,现以Maya和Virtools两种设计软件应用为例,设计一套行之有效的虚拟现实三维建筑模型建模方案。首先,结合虚拟现实技术、三维建模技术等相关技术,从数据采集、数据优化处理、模型创建和材质贴图4个方面入手,使用Maya设计软件创建虚拟现实三维建筑模型。其次,从Virtools简介、Virtools导入模型、模型控制与整合等方面入手,使用Virtools设计软件控制三维建筑模型。最后,进行对比实验。结果表明：在以上两种设计软件的应用背景下,所设计的虚拟现实三维建筑模型建模方案具有较高的可靠性和可行性,完成了对三维建筑模型的科学构建,为人们提供身临其境的感觉,完全符合实际应用需求。希望通过这次研究,为技术人员提供有效的借鉴和参考。     

基于虚拟现实的潜艇虚拟装配系统

该系统是基于虚拟现实技术的潜艇虚拟装配系统。系统使用Creator／Vega虚拟现实软件平台实现,建立非常真实的虚拟装配环境,使用户有身临装配现场的感觉。用户在三维鼠标、位置跟踪器的帮助下可以随意地平移和旋转模型,完成装配操作。同时,该系统运用了Vega容体碰撞检测技术,较好地解决了虚拟装配中的瓶颈--实时碰撞检测。此系统大大缩短了设计周期,节省了设计制造的费用。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.