基于Internet的多用户共享虚拟环境框架的研究

多用户共享虚拟环境是指网络化的协同虚拟现实系统，在该环境中多个用户之间通过各自的三维图形表示实现在虚拟环境中的多人感知，用户之间的交互以及对虚拟对象的协同操纵，在综合分析现有系统以及Internet的开放性标准化需求基础上，提出了一种基于Internet的多用户共享虚拟环境解决方案，即多用户共享虚拟环境框架（multi-user shared virtual envitonment framework,MSVEF)，该框架描述了多用户虚拟环境的体系结构，定义了基于XML的相关交互协议，通过在原型系统中的初步应用，证明该框架可以支持不同网络平台的用户在同一个虚拟场景中的再现与交互。     

分布式虚拟环境协同对象管理

VRML(Virtual Reality Modeling Language)侧重于虚拟环境中几何实体的3D描述，对于系统活动对象(包括用户替身和系统对象)的交互和协同却没有提供很好的支持。为解决这一问题，本文从调用的角度对分布式虚拟环境中资源的分配和活动对象间的交互和协同管理进行研究，构建一个虚拟环境活动对象协同和交互软件模型，对环境的资源以及环境对象间进行交互和协同时的调用进行了形式化的描述。     

多用户共享虚拟环境中VRML系统模型

提出一个多用户共享虚拟环境中,基于VRML的虚拟现实协同系统模型。采用B/S结构,设计了模型的工作流程,重点对虚拟场景与用户替身、VRML场景通讯、模型的协同并行控制、模型中数据交互等关键技术进行了描述和实现。该模型能够实现多用户共享虚拟环境空间的一致性、网络通讯的及时性和多用户替身行为的真实性。原型系统的实现验证了模型的可行性。     

交互分析模型在协作虚拟环境中实现动态兴趣管理

目前，许多传统的协作式虚拟环境应用主要采用Grid和Locale概念来实现虚拟环境中用户的兴趣管理．但是，当其应用在基于虚拟人的社交性协作仿真时，这些基于位置的兴趣管理方法具有一定的局限性．针对社交性协作仿真这一类虚拟环境应用，提出一种新的在协作虚拟环境中采用动态交互分析的兴趣管理模型．首先定义了兴趣网络和兴趣矩阵的概念；然后描述了交互分析方法，通过该方法来实时分析虚拟人的兴趣焦点；最后在该模型的基础上实现了一个原型虚拟环境系统，并演示了该模型在优化场景绘制和协同感知上的作用．     

基于角色的分布式协同虚拟环境建模

目前多数分布式协同虚拟环境建模,主要是解决异构性、可扩充性和行为真实感方面的问题,忽视了系统的安全性问题.而在实际的应用中,不同的用户具有不同的职责和权限.如果不进行安全方面的考虑,就会出现越权操作或非法访问的问题.本文针对分布式协同虚拟环境中用户访问权限的不同,提出了基于角色的分布式协同虚拟环境系统模型,给出了该模型的一种实现,并在应用系统中进行了实例验证.     

协同虚拟环境分层协作感知模型研究

协作感知是协同虚拟环境用户协作和交互的基础,目前没有一种协作感知模型适用于所有虚拟协作应用.介绍了协同虚拟环境和协作感知的定义,分析了协同虚拟环境中用户协作过程和任务关系,引入角色理论和Agent技术对协同虚拟环境和协作者的操作权限进行表示,通过对角色任务图分解/合并划分协作感知层次,建立协作感知模型量化计算感知强度,动态组建协作虚拟组,提高通信效率.     

分布式虚拟环境综述

在分布式虚拟环境中,位于不同物理位置的多个用户或多个虚拟环境通过网络相互联结,进行信息共享和交互.该文结合作者的研究工作,从分布式虚拟环境的产生、需求和特征、模型和结构以及系统关键技术这几个方面对分布式虚拟环境的研究情况进行综述,讨论了存在的问题和进一步的发展方向.     

基于协同虚拟环境的装配设计系统

针对分布式环境中复杂产品协同开发的装配设计需求,研究基于协同虚拟环境的装配设计系统的体系结构和关键技术,提出分布式条件下支持多用户实时交互操作的协同虚拟装配方法,包括复杂场景高分辨率实时渲染和多通道沉浸输出方案。以此为基础开发分布式协同虚拟装配环境,并通过面向汽车整车的多用户协同虚拟装配实例验证了系统的有效性。结果证明,用户可在该系统中完成复杂产品的协同虚拟装配设计工作。     

Internet上基于多Agent的分布式协同虚拟环境

在分析了目前分布式协同虚拟环境的研究现状以及存在问题的基础上，指出在这种系统中结合多Agent技术的可能性和必要性。着重研究了Internet上基于多Agent的分布式协同虚拟环境实现中的若干关键技术。     

基于手势的交互式虚拟环境

交互式虚拟现实系统能够为用户提供直观自然的用户接口。使用手势,用户可以更加高效地与虚拟环境进行交互。但随着系统中识别手势的增多,正确手势的识别率和系统的性能会跟着下降。文章提出用交互状态解决手势识别率和系统性能下降问题,并给出了实现方案。     

分布式地学虚拟环境研究

讨论了分布式地学虚拟环境的概念,特征以及与GIS的相互关系,从系统结构,数据模型,交互界面和开发工具方面,对分布式地学虚拟环境的系统框架进行了研讨。最后,从理论,技术和应用层面介绍了关于分布式地学虚拟环境的研究热点和难点,并讨论了进一步的研究方向。     

The design-by-adaptation approach to universal access: learning from videogame technology

This paper proposes an alternative approach to the design of universally accessible interfaces to that provided by formal design frameworks applied ab initio to the development of new software. This approach, design-by-adaptation, involves the transfer of interface technology and/or design principles from one application domain to another, in situations where the recipient domain is similar to the host domain in terms of modelled systems, tasks and users. Using the example of interaction in 3D virtual environments, the paper explores how principles underlying the design of videogame interfaces may be applied to a broad family of visualization and analysis software which handles geographical data (virtual geographic environments, or VGEs). One of the motivations behind the current study is that VGE technology lags some way behind videogame technology in the modelling of 3D environments, and has a less-developed track record in providing the variety of interaction methods needed to undertake varied tasks in 3D virtual worlds by users with varied levels of experience. The current analysis extracted a set of interaction principles from videogames which were used to devise a set of 3D task interfaces that have been implemented in a prototype VGE for formal evaluation.     

Dynamic interactions in physically realistic collaborative virtual environments

This work describes our efforts in creating a general object interaction framework for dynamic collaborative virtual environments. Furthermore, we increase the realism of the interactive world by using a rigid body simulator to calculate all actor and object movements. The main idea behind our interactive platform is to construct a virtual world using only objects that contain their own interaction information. As a result, the object interactions are application independent and only a single scheme is required to handle all interactions in the virtual world. In order to have more dynamic interactions, we also created a new and efficient way for human users to dynamically interact within virtual worlds through their avatar. In particular, we show how inverse kinematics can be used to increase the interaction possibilities and realism in collaborative virtual environments. This results in a higher feeling of presence for connected users and allows for easy, on-the-fly creation of new interactions. For the distribution of both the interactive objects and the dynamic avatar interactions, we keep the network load as low as possible. To demonstrate the effectiveness of our techniques, we incorporate them into an existing CVE framework.     

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.     

面向网络实验教学的虚拟协同装配技术研究

基于网络实验教学环境下对虚拟协同装配提出的不同需求,分析了其与面向设计的协同装配实现技术之间在定义、目的等方面存在的差异,提出了面向网络教学下虚拟协同装配的概念,并界定了其内涵及实现时需要考虑的因素。研究了支持协同装配的虚拟模型实验室的搭建、虚拟协同装配的语义信息表达模型和装配过程中干涉检测的方法,提出了网络协同虚拟装配实验平台体系的架构方法,并就系统的功能实现、虚拟协同装配执行过程进行了阐述,最后以柱塞泵示例了解系统的初步实现情况。     

基于对等结构的虚拟地理环境系统研究

本文在传统的网络结构基础上,结合P2P技术思想,建立适合大规模用户参与的虚拟地理环境的分布式网络结构,重点研究在该网络结构下的用户节点组织、资源注册、资源发现和失效恢复,以网络环境下的大规模地形实时漫游和视频协同为例,设计和实现了一个原型系统并进行了初步实验。     

一种基于网格的协作学习系统的研究

该文针对协作学习系统存在的协作应用服务层适应性差,不能按照学习者需求动态组合虚拟群组,以及工作流式服务的适应性关联等问题,提出了一种采用CSCL原理、WebServices技术和知识库技术建构适应性协作学习平台的解决方案。重点探讨了协作学习平台的体系结构、适应性协作学习建模以及支持协作学习的知识库建构等问题。     

A self-configurable large-scale virtual manufacturing environment for collaborative designers

As manufacturing environments are getting distributed and increasing in size, the related virtual environments are getting larger and more closely networked together. This trend has led to a new paradigm—large-scale virtual manufacturing environment (LSVME). It supports networked and distributed virtual manufacturing to meet manufacturing system requirements. Since it contains a large number of virtual components, an effective data structure and collaborative construction methodology are needed. A metaearth architecture is proposed as the data structure for representing LSVME. This architecture consists of virtual space layer, mapping layer, library layer and ontology layers, which describe interaction among virtual components and has the ability to analyze the characteristics of virtual environment. In addition, it increases reusability of virtual components and supports self-reconfiguration for manufacturing simulation. A heuristic construction method based on graph theory is proposed using this architecture. It prevents redundant design of virtual components and contributes to an effective construction scheduling technique for collaborative designers.     

A collaborative virtual geographic environment based on P2P and Grid technologies

Solving a geographic problem usually requires collaborative work among a group of people in different geographic locations. Collaborative virtual geographic environment (CVGE), an integrated technology, offers an intuitive, efficient, and interactive visualization environment through which geographically separated users can explore complicated spatial information and conduct collaborative work. In this paper, two new technologies, Peer-to-Peer (P2P) and Grid computing, are tightly coupled to develop a CVGE system. This paper evaluates the potential contributions of the P2P and Grid technology to CVGE systems. Using a Grid based system architecture efficiently integrates and shares geographically distributed resources as well as modeling procedures built on different platforms. To offer a shared and interactive virtual collaborative geographic environment for resolving geographic problems, we developed several P2P services including a terrain visualization collaboration service and a video collaboration service. Finally, a CVGE prototype system is implemented for collaboration on silt dam planning on the Loess plateau. The experimental results show that the scheme developed in this paper is efficient and feasible.     

面向智能制造加工的虚拟调试系统开发与应用

为了解决智能制造加工系统的调试成本高、周期长及风险大等问题,研究了面向智能制造加工的虚拟调试技术。以智能制造加工系统中机器人、PLC、数控车床及加工中心为研究对象,首先通过工业以太网进行组网并与PC机进行通讯,基于OSGI.NET插件框架开发了交互控制软件,将每个设备驱动做成插件,使得每个插件能够实现当前设备的数据采集、监控及控制。并且在RoboDK软件中建立了系统虚拟的3D模型,通过Redis数据库实现了控制设备和虚拟模型之间的信号交互。然后使用了PLC、机器人控制器、数控车床及加工中心控制器对系统3D模型进行虚拟调试,最后通过实验验证了加工系统的有效性。