1. Background

Web-based distance learning is a hot topic in the present educational community. There are two types of distance learning, synchronous and asynchronous. Asynchronous Web-based distance learning has been widely used within universities and colleges. Usually a teacher sets up a course webpage. Course materials (syllabus, lecture notes, assignments, information sources, tests, etc.) and relevant links are posted on the webpage. Course materials may contain a variety of media, including text, graphic, audio and video. Any student with internet access can view these materials. Teachers and students can communicate with each other via email or through discussion forums. Dr. Zaslavsky's GIS course and Dr. Whitney's CS courses are good examples of asynchronous distance learning. Although it is cost-effective and easy to be managed by teachers, asynchronous distance learning has some shortcomings, such as poor teacher-student interaction and low degree of information sharing..

Web-based synchronous distance learning can achieve a greater degree of information sharing between students and teachers. Participants are basically in a virtual classroom via web. They can listen and see each other. They can share information in text or graphical form. What is more interesting is that they can even share a computer application synchronously. To implement synchronous distance learning,  we need a computer program, which is called collaborative environment. This program should be installed on every machine in which teachers or students use. Usually, a collaborative environment comes with some built-in tools we can use for distance learning, such as chat, whiteboard, shared web browser, audio and video. In addition, each collaborative environment usually has an application programming interface (API), users can use API functions to build their own collaborative applications or tools to meet their specific needs.

There are a few collaborative environments available now. Each has its cons and pros. This article is intended to summarize four collaborative environments, Habanero, Tango, NetMeeting and SciVis. All of them are general-purpose collaborative environments except for SciVis, which is specially for scientific data visualization. It is based on our recent experience testing and using these environments. The article is divided into three sections:

Overview
Comparisons of Feature and Performance
Installation and User's Guide
Development Issues
 

• Habanero

• Vendor       The National Center for Supercomputing Applications (NCSA), University of Illinois at Urbana-Champaign
• Web site      http://www.ncsa.uiuc.edu/SDG/Software/Habanero
• Contact
• tmclaren@ncsa.uiuc.edu

bievenue@ncsa.uiuc.edu
• Snapshot    here

•  Tango

• Vendor       Northeast Parallel Architecture Center (NPAC), Syracuse University
• Web site     http://trurl.npac.syr.edu/tango
• Contact
• marek@npac.ssyr.edu (for administrative issues)
• toju@npac.syr.edu (for development issues)
• Snapshot    here

• NetMeeting

• Vendor        Microsoft
• Web site       http://www.microsoft.com/netmeeting
• Contact        none
• Snapshot    here

 
• SciVis

• Vendor        Northeast Parallel Architecture Center (NPAC), Syracuse University
• Web site       http://kopernik.npac.syr.edu:8888/scivis
• Contact
• scott@npac.syr.edu (for administrative issues)

bki5@npac.syr.edu (for development issues)
• Snapshot    here

4. Installation and User's Guide
 

4.1 Habanero

• Installation Instruction
• NT
• Download the software. The current version is Habanero v2.0 Beta 1 for Windows.
• Follow the instructions to install the software.
• The most important is to modify the file of user.props. See an example of user.props.
• Unix
• Download the software. The current version is Habanero v2.0 Beta 1 for Unix.
• Follow the instructions to install the software.
• The most important is to modify the file of user.props. See an example of user.props.
• User's Guide
• NT
• To run client, type "java Habanero -listen 3001" if you want client to use port number 3001. You can write a batch file to set all relevant environment          variables, port number and command to run client.
• To run server, type "java HabaneroServer -listen 2000" if you want client to use prot number 2000. You can also write a batch file to do it.
• Read Readme and check out the docs to get familiar with the environment and applications.
• Unix
•  Same as NT and you can write a script to set environment variables and run client or server.

• Installation Instruction

• NT
• Client (web browser plugin) and server
• Download  the plugin or server individually. The current version is Tango 1.0 beta 4 for Windows 95/NT.
• Click this self-extractable file and Tango will be installed automatically.

• Unix
• Client (web browser plugin) and server
• Download the plugin or server individually. I downloaded Solaris 2.5.1 version. Other Unix versions, like IRIX, Linux and SunOS 4.1 are also available.
• Follow the on-line instructions after entering download page to complete the installation.
• Note
• It is not necessary to install your own server. You can select one of installed servers when you login from Tango main page.
• Check README and here to find more information about installation.
 
• User's Guide

• NT
• Client (web browser plugin)
• Launch the Netscape Navigator. Go to Tango main page and click " login one of  Tango Servers"; and then click "Start Tango". Answer OK to the question " Have you installed Tango plugin?". Select one of servers and click "connect". Then Control Applications applet will come up and you can select whatever applications you like.
• The first time you launch Tango after installation, a privilege window may come up. Check "remember this decision" and click "grant". You can launch Tango. This privilege window will not come up for the following launching.
• Server
• Follow the instructions to install the server.

• Unix
• Client (web browser plugin)
• Same as NT. Make sure you already run "source tangorc" before launching browser.
• Server
• Run tango_start, which will set relevant environment variables and launch the server.

• Installation Instruction
• Download the self-extracted file. The current version is NetMeeting 2.1.
• Click the file and follow the the instructions.

 
• User's Guide
• Check out Help in the program.
• A demo and tutorial is available too.

• Installation Instruction
• NT
• Download the software. The current version is SciVis 1.0. Before doing that, you need to install JDK 1.1.3 or higher.
• Follow the instructions to install the software.
• Unix
•  Same as NT.
•  User's Guide
• NT
• You need to create a batch file by yourself to set environment variables and run SciVis. The built-in program to create script is not for NT. Here is an example batch file.
• Check out the User's Guide to get familiar with the environment.
• Unix
• Simply follow the instructions in the README to create a script file called "run" for instance. This script file set all relevant environment variables and run SciVis.
• Check out the User's Guide to get familiar with the environment.