基于Web的在线虚拟实验室的研究

华中科技大学

硕士学位论文

基于Web的在线虚拟实验室的研究

姓名：白洁婷

申请学位级别：硕士

专业：软件工程

指导教师：江建军

20090525

华中科技大学硕士学位论文

摘要

实验教学在高校工科教育中有着相当重要的地位，但是长期以来传统的实验设备和实验教学方法却相对滞后，开放程度低，这在很大程度上制约了实验教学质量的提高和人才的培养。教育有限的投入无法满足实验设备的昂贵、更新速度快、场地限制的要求，因此，构建基于虚拟仪器技术和Web技术的实验教学平台备受关注。本文在综述国内外在线虚拟实验室的发展现状以及相关的实现技术，提出了基于网络在线虚拟实验室的一个设计方案。着重解决目前在线实验存在的资源共享问题，实现共享仪器设备、数据资源和计算机资源。

在线虚拟实验室基于B/S模式，建立三层体系结构，分别为数据采集层、服务器层和用户层。系统采用了虚拟仪器控制技术、网络技术和组件开发技术，研究了DataSocket技术实现远程测量和控制的方法。通过这个系统，实践了Web相关技术在实验平台中的应用，实现了网络通信和开放式交互实验环境的建立。

通过制定可视化的实验流程、动态的引入、创建设备实验对象，研究了一个在线虚拟实验室系统的具体实现。在此系统中，采样了减少网络流量的AJAX技术，实现实时的异步更新，大大减轻了服务器的负担。在排队理论的基础上，采用了消息队列，避免了对硬件以及虚拟仪器的共享冲突问题。

结合信号采样与恢复实验实例，对整个系统进行了测试与评估，获得系统中的实验结果。在层次化和模块化的设计思想下，描述了系统数据控制层和用户层的功能，对各个模块分别进行了详细的阐述。表明了该系统的实现不仅在功能上是有效的，且整个系统具有良好的通用性和可扩展性。

关键词：在线虚拟实验 DataSocket通信技术B/S结构Web技术

华中科技大学硕士学位论文

Abstract

Experimental teaching has been playing an important role in the engineering course in the higher education, but the out-date experimental teaching equipments and teaching method have been run a long time, thus, the quality of the experimental teaching has largely been obstructed. It is a truth that the limited investing to the education cannot meet the ends of the expensive equipments, fast refresh rate of the equipments and the limiting of the room for the experiments, the building of the Virtual Instruments(VI) has been received much concern. This thesis is to propose a design proposal of an online virtual laboratory based on the Web application through summarizing of the development of the VI laboratory and the related techniques home and abroad. We put emphasis on the problem of the resource sharing in the current online laboratory so that the researchers or the students can share the equipment and the computer resources.

Based on the B/S structure, three-layer architecture has been built. There are Data Acquisition Layer, Server Layer and User Layer. By using the VI controlling techniques, Internet techniques and Component techniques,the DataSocket technology which is to implement the remote measurement and control methods has been studied. In this system, Web techniques are applied in the experimental platform, and network communication and the open and interactive experimental environment are implemented.

Through formulating the visual experimental procedure, dynamically introducing and creating the subjects to devices, the implementing of the system of online VI laboratory has been researched. The AJAX technique which is arm to reduce network traffics on the server and achieve asynchronous real-time updates has been researched. Base on the Queuing theory, the research adopts Message Queue in order to avoid the sharing problem from the hardware and Virtual Instruments.

Finally, the signal sampling and recovering experiment as a test case on the system is carried on to evaluate the system performance and acquire the experimental data. Under the thinking of modularization and layering, the functions of every layer of the system and every module of the system have been described in details. As a result，it is proved that the system is to be effective, also it can be in common use and can be extended.

Keywords：Online Virtual Experiment, DataSocket communication technique, B/S structure, Web