Web2.0环境下的高校虚拟学习社区设计

虚拟学习社区作为一种数字化的学习环境,在高校中广泛应用于正式学习和非正式学习,利用Web2.0技术进行改造,可以解决传统虚拟学习社区中寻找学习伙伴与归属感难、分享学习资源难等问题.综合分析了Web2.0具有实现个性化、明确归属感、变革信息源等技术特性,结合了学习者的需要和虚拟学习社区的基本结构.设计了虚拟学习社区的五大功能模块,提出了高校虚拟学习社区的结构模型.基于Web2.0技术构建的虚拟学习社区模型基本可以通过开发实现,并能在高校有效应用     

Intranet虚拟Web服务器的实现

一、问题 建企业Intranet时,不需要给每一个部门分配一台不同的计算机作为其Web服务器,可在企业主Web服务器上为不同的部门创建不同的虚拟Web服务器,并给不同的虚拟Web服务器分配不同的域名。网络用户访问各部门的域名地址时是透明的。这样做的优点是方便集中管理,减少设备投资。在网络教学培训环境的建造中,可采用该技术,用一台服务器模拟出多个Internet网站,这样对降低培训成本也是非常有意义的。本文就Win-dows NT4.0服务器上创建虚拟 Web服务器的技术进行探讨。 二、规划 首先必须为想要创建的主Web服务器和虚拟Web服务器从ISP处获得一组IP地址,并需在主Web服务器上为每一个虚拟Web服务器创建不同的子目录,作为其域名的宿主目录。例如,Company公司规划方案如下:     

Web应用服务器研究综述

Web应用服务器是Web计算环境下产生的新型中间件,为创建、部署、运行、集成和管理事务性Web应用提供一个跨平台的运行环境,被认为是自关系型数据库以来最令人激动的企业应用技术.诸多IT企业纷纷推出其各自的Web应用服务器产品和系统,学术界也对这种热门领域产生了浓厚的兴趣.在分析Web计算环境下传统中间件发展所遇到的问题的基础上,介绍Web应用服务器的起源和发展、运行模式以及评测基准,然后对Web应用服务器研究现状进行综述,主要包括Web应用服务器的定义、体系结构、组件容器、分布事务处理、负载平衡、高速缓存、Web Service等研究热点和关键技术.根据评测基准,对若干主流Web应用服务器从功能和性能两个方面进行分析和比较.此外,还指出了Web应用服务器目前存在的不足以及未来的发展趋势.     

WS-T协议族及其应用研究*

介绍了Web服务和事务的相关概念,阐述了传统事务处理协议在Web服务处理环境中存在的问题;然后结合目前流行的WST协议族对Web事务处理作了分析;最后根据分析总结了解决问题的思路,以及在Web服务事务处理中建议采用的策略。     

基于BTP的Web服务事务协调研究与实现

Web服务技术为异构应用之间的集成和互操作提供了有效的解决手段。目前的Web服务还缺乏全局的事务环境,传统的事务模型不再适用于新的Web环境下的要求。针对Web服务中事务处理的协调问题,分析现有的事务处理模型和协议,设计实现了一个基于BTP协议的Web服务事务原型系统,把用于Web服务事务处理的BTP协议和用于传统事务的两阶段提交协议相结合来协调Web服务中的事务。通过运行应用实例,验证了原型系统的可行性,该系统具备协调短期事务与长事务的能力。     

基于Web的虚拟实验系统实现

实验教学是培养学生专业素质的重要途径,基于Web的虚拟实验教学对发展现代教育思想、提高教育技术水平、改善实验环境、优化教学过程将产生深远的影响.文章指出了虚拟实验室的内涵和特点,在此基础上对构建虚拟实验室的体系结构进行了研究,最后对基于Web的虚拟实验系统实现的关键技术进行了探讨并对虚拟实验室进行了实现.     

基于替代和补偿的嵌套Web Service事务模型

作为一种崭新的并行计算模式,Web Service以其平台独立性、松耦合及自治性等优势,在涉及复杂业务流程的事务性服务行业具有极大潜力和需求.考虑到Web Service环境的限制和特征,传统事务模型无法适应.从Web Service事务系统体系结构出发,分析Web Service的特点及Web Service事务性应用在开放的Web环境下的特性,提出了一个基于替代和补偿的嵌套Web Service事务模型,阐述了结合替代和补偿的Web Service事务结构和处理,给出了形式化描述.     

Web应用开发模式分析

按照Web开发的应用中是否使用独立的Web服务器,Web开发的应用模式分为依赖式和独立式两种.在对两种应用模式的开发技术和手段进行归类分析的基础上,分别对每种应用模式的各自特性从技术角度进行概括性论述.通过上述分析和讨论,目的在于建立较全面的Web开发的应用模式体系概念,丰富和延伸Web开发的应用框架结构.     

基于BTP的Web服务事务协调研究与实现

Web服务技术为异构应用之间的集成和互操作提供了有效的解决手段.目前的Web服务还缺乏全局的事务环境,传统的事务模型不再适用于新的Web环境下的要求.针对Web服务中事务处理的协调同题,分析现有的事务处理模型和协议,设计实现了一个基于BTP协议的Web服务事务原型系统,把用于Web服务事务处理的BTP协议和用于传统事务的两阶段提交协议相结合来协调Web服务中的事务.通过运行应用实例,验证了原型系统的可行性,该系统具备协调短期事务与长事务的能力.     

基于Web的空间虚拟实验室计算机模拟系统

空间虚拟实验室建设对促进空间物理研究具有重要的意义。计算机数值模拟系统是其中一个非常关键的子系统,将卫星和地面观测以及理论分析紧密结合。基于Web的空间虚拟实验室模拟系统屏蔽了传统空间物理数值模拟过程的复杂性,以Web的形式提供了空间物理模拟中所需的主要功能,使得模拟工作可以通过浏览器实现。本文结合武汉大学空间数据和计算中心(SDCC)基于Web的空间虚拟实验室模拟系统的建设情况,根据当前国际动态和科学研究的需要,给出了具体的设计与实现。     

Virtual environments applications and applied ergonomics

The usability of virtual environments has attracted considerable efforts from ergonomists. Work has included studies of the side or after effects of participation in a virtual environment (VE) as well as the appropriateness of the Virtual Reality hardware and software interfaces and the understanding of factors which determine participant performance. Equally important for applied ergonomics is to understand how best to specify, build, implement and evaluate virtual environment solutions to everyday industrial, commercial, educational and medical problems. The potential value of ergonomics applied to virtual environments, and vice versa, are discussed. Two particular instances of VE development relevant to applied ergonomics are described - structured development and evaluation of industrial training and participatory redesign of workplaces. This paper is one of a number of contributions to a special issue on ergonomics in the study and use of virtual environments.     

The influence of virtual presence: Effects on experienced cognitive load and learning outcomes in educational computer games

Does the immersive design of an educational gaming environment affect learners’ virtual presence and how much do they learn? Does virtual presence affect learning? This study tries to answer these questions by examining the differences in virtual presence and learning outcomes in two different computer-based multimedia environments: a gaming environment with high immersive design vs. hypertext learning environment with low immersive design. As the main focus, the effect of virtual presence on learning is also explained and tested. By identifying virtual presence as a variable that may determine learning, it is argued that computer gaming environments present a new challenge for researchers to investigate, particularly, the effects of virtual presence on the immersive design of games in order to help designers to predict which instructional configurations will maximize learning performance. In general, results revealed that the high-immersive gaming environment leads to the strongest form of virtual presence but also decreased learning. Although regression analyses indicate that virtual presence positively influences trivial- and non-trivial learning outcomes, learners who learned in a low-immersive environment outperformed the gaming group. A mediation analysis showed that the relation between virtual presence and non-trivial learning outcomes is partly mediated through increased cognitive load.     

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.

Adaptation in virtual environments: conceptual framework and user models

When interacting in a virtual environment, users are confronted with a number of interaction techniques. These interaction techniques may complement each other, but in some circumstances can be used interchangeably. Because of this situation, it is difficult for the user to determine which interaction technique to use. Furthermore, the use of multimodal feedback, such as haptics and sound, has proven beneficial for some, but not all, users. This complicates the development of such a virtual environment, as designers are not sure about the implications of the addition of interaction techniques and multimodal feedback. A promising approach for solving this problem lies in the use of adaptation and personalization. By incorporating knowledge of a user’s preferences and habits, the user interface should adapt to the current context of use. This could mean that only a subset of all possible interaction techniques is presented to the user. Alternatively, the interaction techniques themselves could be adapted, e.g. by changing the sensitivity or the nature of the feedback. In this paper, we propose a conceptual framework for realizing adaptive personalized interaction in virtual environments. We also discuss how to establish, verify and apply a user model, which forms the first and important step in implementing the proposed conceptual framework. This study results in general and individual user models, which are then verified to benefit users interacting in virtual environments. Furthermore, we conduct an investigation to examine how users react to a specific type of adaptation in virtual environments (i.e. switching between interaction techniques). When an adaptation is integrated in a virtual environment, users positively respond to this adaptation as their performance significantly improve and their level of frustration decrease.     

A domain-oriented end-user design environment for generating interactive 3D virtual chemistry experiments

Three-dimensional virtual worlds are potentially feasible for building virtual educational environments. However, educators face technical challenges to apply these technologies because creating virtual educational environments based on virtual worlds demands 3D modeling and programming skills. This paper proposes a method to lower the technical barriers through domain-oriented interfaces with languages and environments that are familiar to educators. A domain-oriented end-user design environment, iVirtualWorld, is designed and developed to implement the proposed method in a specific educational domain, namely introductory chemistry experiments. This web-based environment provides end-users with domain-oriented building blocks, which can be assembled to create 3D virtual chemistry experiments. A usability evaluation and a comparative case study are designed to evaluate the system among chemistry educators, who are the target audience. The usability evaluation contains a task requiring participants to create a 3D virtual chemistry experiment and a voluntary semi-structured interview. The case study compares a virtual experiment generated using iVirtualWorld with an experiment in a commercial virtual chemistry laboratory system. The results show that 1) the domain-oriented end-user design environment enables participants to generate the 3D virtual chemistry experiment within 30 min; 2) participants gain confidence on creating 3D virtual experiments by themselves using iVirtualWorld; 3) participants confirm the usefulness of applying the system in introductory chemistry education; and 4) iVirtualWorld is considered more intuitive and straightforward for students to focus on finishing the experiment without being distracted than the commercial virtual chemistry laboratory system. Areas that can benefit from the system most and areas where the system is less effective are identified by participants. The responses also reveal the limitations of the current system and suggest directions for future improvement.     

基于云服务的Java虚拟教学环境应用研究

随着云服务教育技术的发展,高等院校Java教学模式发生了重大的改革和变化。详细地分析了传统教学模式存在的不足,阐述了虚拟教学环境的背景理论,同时给出了基于云服务的Java虚拟教学环境功能和系统架构,激发学生学习积极性,创新教学模式。     

High utility pattern mining over data streams with sliding window technique

Processing changeable data streams in real time is one of the most important issues in the data mining field due to its broad applications such as retail market analysis, wireless sensor networks, and stock market prediction. In addition, it is an interesting and challenging problem to deal with the stream data since not only the data have unbounded, continuous, and high speed characteristics but also their environments have limited resources. High utility pattern mining, meanwhile, is one of the essential research topics in pattern mining to overcome major drawbacks of the traditional framework for frequent pattern mining that takes only binary databases and identical item importance into consideration. This approach conducts mining processes by reflecting characteristics of real world databases, non-binary quantities and relative importance of items. Although relevant algorithms were proposed for finding high utility patterns in stream environments, they suffer from a level-wise candidate generation-and-test and a large number of candidates by their overestimation techniques. As a result, they consume a huge amount of execution time, which is a significant performance issue since a rapid process is necessary in stream data analysis. In this paper, we propose an algorithm for mining high utility patterns from resource-limited environments through efficient processing of data streams in order to solve the problems of the overestimation-based methods. To improve mining performance with fewer candidates and search space than the previous ones, we develop two techniques for reducing overestimated utilities. Moreover, we suggest a tree-based data structure to maintain information of stream data and high utility patterns. The proposed tree is restructured by our updating method with decreased overestimation utilities to keep up-to-date stream information whenever the current window slides. Our approach also has an important effect on expert and intelligent systems in that it can provide users with more meaningful information than traditional analysis methods by reflecting the characteristics of real world non-binary databases in stream environments and emphasizing on recent data. Comprehensive experimental results show that our algorithm outperforms the existing sliding window-based one in terms of runtime efficiency and scalability.     

Binding Virtual Environments to Toolkit Capabilities

There are many toolkits and development environments that aid the process of constructing virtual environment applications. Many of these development environments encourage customising a virtual environment's design while rapid prototyping within the confines of a toolkit's capabilities. Thus the choice of the technology and its associated support has been made independent of the end-use requirements of the final system. This can bias a virtual environment's design by implementation based constraints. We propose that an alternative approach is the consideration of virtual environment requirements in the context of an inspectable design model, to identify the requirements that a toolkit will need to support. In the context of an example, we present a selection of design requirements that we consider important for virtual environment design in general. We explore how these requirements might be mapped to different capabilities using Virtual Reality Modelling Language (VRML) as a concrete example of a platform technology.     

Educational virtual environments: design rationale and architecture

The use of collaborative virtual environments in e-learning is one of the most promising uses of virtual reality technology. While much research has been done in the area of networked virtual environments corresponding to the sharing of events, very little research has been done on specific services and functionality. However both the requirements and the kind of the offered services affect significantly the design of a system. In this paper we present the design and implementation of a platform suitable for educational virtual environments, which are collaborative virtual environments aiming at offering collaborative e-learning services to the users. Apart from the platform itself, we present the technological choices, and a new method for sharing virtual environments. Furthermore, we present an e-learning environment to support e-learning services using collaborative virtual environments from both the technical and functional point of view, along with the end-user evaluation results.