Coordination components for collaborative virtual environments

This paper deals with the behavior of virtual environments from the collaboration point-of-view, in which actors (human or virtual beings) interact and collaborate by means of interdependent tasks. In this sense, actors may realize tasks that are dependent on tasks performed by other actors, while the interdependencies between tasks (through resource management and temporal relations) delineate the overall behavior of a virtual environment. Our main goal is to propose an approach for the coordination of those behaviors. Initially a generic study of possible interdependencies between collaborative tasks is presented, followed by the formal modeling (using Petri Nets) of coordination mechanisms for those dependencies. In order to implement such mechanisms, an architecture of reusable and pluggable coordination components is also introduced. These components are used in an implementation of a multi-user videogame. The presented approach is a concrete step to create virtual societies of actors that collaborate to reach common goals without the risk of getting involved in conflicting or repetitive tasks.     

Haptic Cooperative Virtual Workspace: Architecture and evaluation

The Haptic Cooperative Virtual Workspace (HCVW), where users can simultaneously manipulate and haptically feel the same object, is beneficial and in some cases indispensable for training a team of surgeons, or in application areas in telerobotics and entertainment. In this paper we propose an architecture for the haptic cooperative workspace where the participants can kinesthetically interact, feel and push each other simultaneously while moving in the simulation. This involves the ability to manipulate the same virtual object at the same time. A set of experiments carried out to investigate the haptic cooperative workspace is reported. A new approach to quantitatively evaluate the cooperative haptic system is proposed, which can be extended to evaluate haptic systems in general.     

Dynamics of Flexible Multibody Systems Using Virtual Work and Linear Graph Theory

By combining linear graph theory with the principle of virtualwork, a dynamic formulation is obtained that extends graph-theoreticmodelling methods to the analysis of flexible multibody systems. Thesystem is represented by a linear graph, in which nodes representreference frames on rigid and flexible bodies, and edges representcomponents that connect these frames. By selecting a spanning tree forthe graph, the analyst can choose the set of coordinates appearing inthe final system of equations. This set can include absolute, joint, orelastic coordinates, or some combination thereof. If desired, allnon-working constraint forces and torques can be automaticallyeliminated from the dynamic equations by exploiting the properties ofvirtual work. The formulation has been implemented in a computerprogram, DynaFlex, that generates the equations of motion in symbolicform. Three examples are presented to demonstrate the application of theformulation, and to validate the symbolic computer implementation.     

Pursue or shoot? Effects of exercise-induced fatigue on the transition from running to rifle shooting in a pursuit task

To investigate to what degree exercise-induced fatigue influences behavioural choices, participants' transition from running to rifle shooting in a pursue-and-shoot task was assessed. Participants ran on a treadmill and chased a target in a virtual environment and were free to choose when to stop the treadmill and shoot at the target. Fatigue increased progressively throughout the 20-minute test. Results indicated that shooting accuracy was not affected by fatigue. However, the distance to the target at which participants decided to shoot showed a U-shaped relationship with fatigue, R² = 0.884, p = 0.013. At low fatigue levels (ratings of perceived exertion [RPE] < 6.5), the distance to the target at which participants shot decreased, whereas at higher fatigue levels (RPE > 6.5) shooting distance increased again. At high levels of fatigue, participants stopped running sooner, aimed at the target longer and shot less often. Findings indicate that physiological parameters influence not only perception but also actual transitions between different actions.     

基于虚拟实训基地（车间）的工学结合人才培养模式研究

为了寻求适合自身的人才培养模式,分析了当前国内高等职业教育人才培养模式的现状,提出了基于虚拟实训基地（车间）的工学结合人才培养模式;从校内实训基地建设、课程体系与学习领域开发、教学模式和＂双师型＂教师培养等四个方面阐述了该人才培养模式的具体内容和切实可行性。     

基于云自适应遗传算法的LVS 负载均衡改进算法

针对LVS系统存在负载倾斜问题,改进了系统中带权值参数的负载均衡算法．先通过服务器节点反馈的参数计算出服务器节点的负载,再采用云自适应遗传算法根据负载为各服务器节点分配权值,进而实现改进算法．实验证明,改进算法比传统算法提高约10％的性能,可使系统有效地实现动态负载均衡．     

虚拟仪器的网络应用及实现

在研究了LabVIEW 7.0网络通信功能的基础上,利用NI公司的PCI-6111数据采集卡,以ASP为脚本环境、以MySql Server为数据库服务器设计并实现了基于校园网的网络虚拟实验平台.该平台较好地利用了虚拟仪器的网络功能,做到了资源共享,实现了网络远程教育与研究.     

虚拟仪器技术在模拟电子技术实验中的应用

给出了虚拟仪器技术的概念。并提出了一种用于模拟电子技术实验的虚拟仪器设计方案。     

校园网格环境构建的关键技术研究

网格计算是新型分布式计算技术。网格是一个集成的计算与资源环境,它能够充分吸纳各种计算资源并将它们转化成一种方便可靠的计算能力。文中论述了网格计算的特点和体系结构及其与传统分布式计算的区别,进而分析了校园网格环境构建的关键技术。校园网格环境的构建是网格普及化必经的关键一步。在校园网格系统构建中除了文中提到的关键技术之外还有诸多问题如安全机制、资源管理、任务管理、通信技术等都有待于进一步研究和具体化。     

虚拟仪器在温度测控系统中的应用

虚拟仪器是由软件实现的，其软件开发平台是LabVIEW。以间歇式造气炉气化层的温度为例，用LabVIEW构建对造气炉气化层温度进行在线实时测量与控制的系统，从而可以降低操作人员的工作难度和强度，提高效率，达到对造气炉状态的实时控制。