摩擦提升机的虚拟样机研究

钢丝绳传动特性是摩擦式提升机设计一个重要的考虑因素.为了研究摩擦提升机提升过程中钢丝绳的动力学特性,为安全运行提供保证,通过虚拟样机技术及其支撑软件ANSYS和RecurDyn,利用相对节点法建立了钢丝绳的多体动力学仿真模型,构建了简化后的摩擦式提升机虚拟样机仿真模型.通过对摩擦提升机虚拟样机的仿真分析,获得了仿真模型的运动学、动力学特性数据,得到了与理论分析相吻合的结果.为设计经济、可靠的多绳摩擦提升机系统提供了有力的工具和实现方法,还可以推广应用到其他挠性传动的分析.     

一种结构化P2P网络动态负载均衡算法的研究

负载均衡是P2P网络的研究热点之一,当前负载均衡技术存在负载均衡程度低、假设条件过多等问题.提出一了种增强型负载均衡算法ELB_P2P,它根据节点的承栽能力为其分配相应大小的可动态调整的ID地址空间以及合理的载荷,在负载转移时自动选择延迟小带宽高的轻栽节点,并引入负载转移流量控制机制.实验表明,相对于Chord等传统P2P协议,ELB_P2P算法有更快的负载均衡速度、更小的负载均衡开销,系统稳定性好,在网络重栽情况下也能取得较低的负载不平衡度,并且对节点属性没有苛刻的限制和假定.     

多轴转向车辆转向杆系的受力分析

某采用机械式液压助力转向的多轴转向车辆,经常出现转向杆系损坏的现象.为了分析转向杆系损坏的原因,进一步提高系统的可靠性,通过大型工程分析软件ADAMS对转向杆系进行虚拟样机建模.利用模型对转向杆系进行了虚拟试验分析,给出了各杆件受力分析的仿真结果.仿真结果分析表明造成转向杆系损坏的原因是由于受力过大,并提出了相应的改进措施.通过改进后测试,对虚拟样机的仿真结果进行了对比,证明虚拟样机模型是正确的,改进措施是有效的.结果使整个杆系最大受力降低了30%.     

The movement patterns and the experiential components of virtual environments

Human movement in virtual environments (VEs) is a largely unstudied area, and there are no well-established methods of measuring it in VEs. Consequently, it is unclear how movement affects the experiential side of VEs. We introduce a novel method of measuring and modelling human movement. A specific information entropy-based modelling method enabled us to identify different movement patterns and analyse the experiential components related to them. The data was collected by registering the movement patterns of 68 participants who were in a virtual house doing a search task. The experiential side of the VE was measured with the Experimental Virtual Environment Questionnaire (EVEQ). Four movement patterns were identified. In addition, fluent movement in VEs was related to a high sense of presence. Moreover, the participants who moved fluently in the environment assessed their skills high. The results show how movement is related the way in which people experience the VE. The movement analysis method introduced here is applicable to other related research areas as well.     

GLSV: Graphics library stereo vision for OpenGL

This work proposes the development of an auxiliary library for use with OpenGL, to facilitate the creation of graphic applications incorporating stereoscopic representation. This library, christened graphics library stereo vision (GLSV), is designed to remove all calculations involving knowledge of stereo vision theory from the task performed by the programmer without the latter having to change the way he/she has been working with the OpenGL library. The GLSV is distributed under the terms of the GNU Library General Public License agreement.     

Collaborative virtual learning environments: design and evaluation

E-learning systems have gone through a radical change from the initial text-based environments to more stimulating multimedia systems. Such systems are Collaborative Virtual Environments, which could be used in order to support collaborative e-learning scenarios. The main aim of this paper is to aid educational designers in selecting, designing and evaluating three dimensional collaborative virtual environments in order to gain the pedagogical benefits of Computer Supported Collaborative Learning. Therefore, this paper initially discusses the potential of three dimensional networked virtual environments for supporting collaborative learning. Furthermore, based on a two-step platform selection process this paper (a) presents and compares three dimensional multi-user virtual environments for supporting collaborative learning and (b) validates the most promising solution against a set of design principles for educational virtual environments. According to these principles, an educational environment has been implemented on top of the selected platform in order to support collaborative e-learning scenarios. The design of this environment is also presented. In addition, this paper presents the results of three small scale studies carried out in a tertiary education department, to assess the educational environment. This environment has been evaluated based on a hybrid evaluation methodology for uncovering usability problems, collecting further requirements for additional functionality to support collaborative virtual learning environments, and determining the appropriateness of different kinds of learning scenarios.

基于硬件加速的几何失真校正研究

分析研究一种新的图形硬件架构CUDA,基于其类C语言硬件开发环境和多线程的硬件执行机制,实现了基于GPU的几何失真校正的数学贴图映射,并根据像素分辨率的不同情况分别进行了实验验证,证明该方法比基于CPU的实现具有更高的场景交互速度,保证了视景系统的真实感和实时性.     

基于Truevision3D的虚拟现实技术

在介绍TV3D引擎的基础上重,点讨论了在Visual C#.NET中使用TV3D引擎实现虚拟现实的方法和步骤.文中采用动态摄像机,当操作键盘或鼠标来移动目标物体时,场景视角和摄像机会自动调整,很简单地就实现了虚拟漫游.实验结果表明,使用TV3D引擎来实现虚拟现实,很多底层的功能很容易实现.     

基于虚拟多传感器信息融合的粮情预警系统

在粮食仓储过程中,通过温湿度传感器、图像传感器采集到的温湿度、图像的实时数据,经过信息处理算法的变换和特征提取,得到具有不同特征信息的虚拟多传感器数据,采用D-S证据理论对数据进行信息融合,对粮食在仓储过程中的霉变、虫害等粮情进行动态预测分析,当发现有不良变化时,该系统能够及时发出预警信息,以保证粮食的储藏安全。     

构建网络虚拟实验室的关键技术研究

网络虚拟实验室的主要功能由网络化虚拟仪器实现。文中重点探讨了网络虚拟实验室的体系结构,虚拟仪器开发系统以及网络化虚拟仪器开发技术。