基于Unity3D的虚拟漫游系统分析

随着我国虚拟技术以及互联网技术的不断发展,虚拟漫游平台的开发与使用受到了更多的关注。基于此,本文提出了一种基于Unity3D的虚拟漫游系统,并对其开发流程、虚拟场景的生成、功能模块设计以及使用的场景建模技术、交互技术、碰撞检测技术、粒子系统这些关键技术进行了分析。     

基于VRML的虚拟校园漫游系统研究

对大规模场景建模和交互技术进行研究,以凯里学院为原型对基于VRML的虚拟校园漫游系统进行设计,并在VRML和3DSMAX等相关系统和平台上部分实现凯里学院虚拟校园漫游系统。     

虚拟城市可视化的研究与实现

“虚拟城市”技术是“数字地球”技术的重要组成部分,其研究戈键足怎样在Internet／Intranet上建立城市的虚拟可视化模型,是计算机科学、信息科学、地球科学、系统科学的有机融合。该文概括了“数字地球／虚拟城市”的基本概念,探讨基于Web、2DVR、3DVR和GIS柏结合的技术开发虚拟城市系统的新仿真模式及其关键技术和整体开发方案。提出了虚拟场景与外界交互的手段和方法,着重研究全景图、三维模型和网络动态交互技术结合实现交互式网络虚拟城市漫游的方法和实现过程,并给出了运行实例。通过该系统可以为城市规划、交通旅游等提供动态可视化显示的全新技术支持。     

多用户网络虚拟校园漫游系统的构建与研究

针对多用户网络虚拟校园漫游系统的难点问题,提出有效的优化解决措施,提高系统的真实感,实时性和交互性,主要研究了网络虚拟现实漫游系统开发的关键技术,包括图像数据收集与处理、三维数字建模、虚拟场景交互、网络传输等技术,结合海南师范大学的具体应用环境,构建了基于网络交互式的虚拟校园漫游系统.     

基于Vega的虚拟漫游系统的设计与实现

分析了Vega的组成结构和视景数据库的建立.使用MultiGen建模工具构建模型、利用VC6.0开发环境和Vega的库函数,以某部队的营房建设为虚拟对象,设计并实现了虚拟漫游系统.系统可提供自动漫游、自由漫游和漫游记录以及施工过程的信息查询等功能.用户可以随意在该营区漫游.     

在Unity3D技术基础上构建虚拟校园漫游系统的研究

智慧型校园建设成为学校数字化和信息化发展的主要趋势,Unity3D技术在虚拟校园漫游系统构建中的应用,构建了一个交互式的虚拟校园漫游场景,可以更直观地对校园景观和校园文化进行体验.对Unity3D技术进行了简单的介绍,对虚拟校园漫游系统的设计需求进行了分析,在Unity3D技术基础上,以MVC架构作为总体架构,构建了虚拟校园漫游系统,并对系统模块功能进行了设计和研究.     

交互式自行车模拟器视景仿真系统开发

视景仿真系统是交互式自行车模拟器的重要组成部分。其给骑车者提供逼真的虚拟三维漫游场景。开发的视景仿真系统硬件上采用PowerWall虚拟现实系统，软件上基于自主开发的虚拟现实通用应用开发平台VR Flier，提高了开发的效率。VR Flier采用面向对象方法设计，能够全面地支持小同领域和不同规模的VR应用开发。视景仿真系统通过优化以及动态调度三维场景模型的方法提高了大范围漫游场景的渲染帧率；并对场景路面坡度及视景转向信号进行平滑处理，获得很好的视景仿真效果。     

基于OpenGL的虚拟校园漫游系统的设计与实现

介绍了虚拟校园漫游系统的设计与开发技术,包括:OpenGL绘图窗口的创建;实体建模;纹理设置和贴图;界面和树的实现;虚拟仿真--利用VC 6.0开发平台,编制程序实现虚拟校园的漫游.该系统可以用于校园三维漫游、校园管理、校园规划等领域.     

VRML虚拟校园漫游与交互技术

鉴于虚拟校园在高校数字化和信息化建设中的重要意义,以石家庄铁道学院为例,探讨VRML构建虚拟场景的漫游与交互技术.以VRML、3DMax等为场景构建工具、以JavaScript为VRML内部脚本和外部脚本接口编程工具,通过VRML与HTML的整合集成,实现了虚拟校园漫游与交互系统,具有导航漫游、对虚拟场景进行交互操作和...     

基于Unity3D的地铁三维虚拟漫游设计

随着虚拟现实技术的飞速发展,如何利用计算机展示现实场景的三维漫游效果,已成为当下研究的热点.以Unity3D为平台,利用3DMax软件进行场景建模,结合Unity3D自身强大的界面交互技术,完成整个南昌地铁一号线虚拟漫游系统的开发.最后通过地面站点全景的外链衔接,实现了地铁站内三维模型场景与地铁站外全景的一体化漫游功能.实践研究结果表明,整个虚拟漫游系统能够给用户带来直观的地铁漫游体验.     

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。     

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.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).