Synchronous Learning at a Distance:
Experiences with TANGO

14 May 1998

Thomas R. Scavo, David E. Bernholdt*, Geoffrey C. Fox, Roman Markowski, Nancy J. McCracken, Marek Podgorny
Northeast Parallel Architectures Center
Syracuse University
111 College Place
Syracuse, NY 13244
Debasis Mitra, Qutaibah Malluhi
Department of Computer Science
Jackson State University
P.O. Box 18839
Jackson, MS 39217
* Author for Correspondence: bernhold@npac.syr.edu


Abstract

In the fall of 1997, and again in the spring of 1998, the Northeast Parallel Architectures Center at Syracuse University taught a computational science course at Jackson State University in Jackson, Mississippi using the TANGO collaboratory system. What made this course unique is that twice a week instructors "met" with students online, showing lecture slides and programming examples, and discussing concepts in real time over the Internet. The goal of the project was to investigate the use of TANGO in teaching a traditional lecture-based course in a distance-learning format.


Introduction

Many academic courses at Syracuse University and elsewhere use technology to enhance the learning experience. For example, commercial textbooks often include CD-ROMs complete with databases, online resources, utilities, and hot links to related material on the World Wide Web. Mailing lists and bulletin board systems (such as USENET) are commonly used to make timely course-related announcements and as a medium to facilitate asynchronous group discussions and administer technical forums. Course material is often published on web servers, which students are encouraged to access at their leisure (that is, asynchronously).

There appears to be no shortage of such course material on the web (especially in the technical fields), although the quality of such material varies greatly. What is clearly missing, however, is a vehicle to deliver educational material synchronously, that is, in real time. Although some "distance learning" courses use chat tools to communicate synchronously, there appears to be few (if any) systems that deliver real-time multimedia content in an authentic, two-way interactive format.

The computational science education group at the Northeast Parallel Architectures Center (NPAC) has developed a huge repository of online course material, including lectures, tutorials, and programming examples in various languages. We believe, however, that a significant majority of students require regular and sustained interaction (i.e., synchronous learning activities) involving teachers and other learners, in addition to asynchronous learning materials. This motivated us to use TANGO to deliver CSC 499 over the Internet.

CSC 499, Programming for the Web

The first offering of Jackson State University (JSU) course CSC 499, Programming for the Web, began on August 18, 1997 and ended December 10, 1997. The same course was taught again the following spring semester from January 8, 1998 to May 5, 1998. CSC 499 is equivalent to Syracuse University course CPS 406, which is also taught as a graduate course (CPS 606).

The goal of CSC 499 is to provide the basic programming skills needed to develop World Wide Web applications. Topics include web architecture, HTML form processing using CGI scripts, and web programming in the language Java. As a CGI scripting language, the students are briefly introduced to the language Perl, but thereafter approximately two-thirds of the course is devoted to Java.

CPS 406/606 is taught at Syracuse in traditional lecture-based format. Students are provided access to a wealth of online material and evaluated on a number of projects, which are assigned, submitted, and graded over the web. See

   http://www.npac.syr.edu/projects/cps606spring98/
for a recent offering of CPS 606.

Students in CSC 499 also had access to asynchronous learning material on the web. From the course home page

   http://www.npac.syr.edu/projects/jsuspring98/

students link to resources covering HTML, CGI (including Perl), and Java programming. These pages contain links to lectures, tutorials, documentation, and numerous examples.

CSC 499, offered as a JSU credit course, included regularly scheduled lectures delivered via TANGO. During these lectures, an instructor would show lecture slides on a workstation in Syracuse, while the students attended class in a lab at JSU. Each lecture slide would appear on the students' workstations as the instructor displayed it. The instructor would deliver the lecture via an audio link, and the students would ask questions either through a chat tool or the audio link.

TANGO

TANGO is a Java-based web collaboratory developed at NPAC. It is implemented with standard Internet technologies and protocols, and runs inside an ordinary Netscape browser window. Although TANGO was originally designed to support collaborative workgroups, in this project it was used to synchronously deliver course materials stored in an otherwise asynchronous repository.

The primary TANGO window is called the control application (CA). From the CA (see Figure 1), participants have access to many tools including:

WebWisdom is a presentation tool for showing lecture slides or foils. The system includes tools that convert a source document prepared with PowerPoint or Persuasion into WebWisdom format. The WebWisdom database consists of over 400 foilsets and 17,000 foils. A foil may have an "addon", which is a link (or links) to supporting material such as online documentation or example programs.

The SharedBrowser is used to "push" learning material onto client screens. It is similar to an ordinary browser window: there is a textfield for typing URLs, a "Back" button, and a history list. When the "master" (that is, the user doing the "pushing") loads a web page into the SharedBrowser, that web page is automatically and simultaneously displayed in all client browsers. Clients may activate links, scroll the window, or otherwise interact with the page as usual, but as the master SharedBrowser loads a new page, that page is automatically loaded into all client browsers. In this way, an instructor may show examples or a student may demonstrate a project.

The WhiteBoard is a handy tool for conveying small amounts of information on-the-fly, say, a code fragment or a simple diagram. TANGO's WhiteBoard is full duplex, that is, any number of clients may write on it simultaneously. Although such a tool is useful for collaborative work, we found ourselves wanting a locking mechanism that would prevent students from inadvertently messing up our real-time drawings.

TANGO's Chat tool was an indispensable part of the synchronous learning process. At least one chat window was on every participant's desktop at all times.

BuenaVista (BV) is a multi-platform, audio/video conferencing system developed at NPAC. It requires limited but consistent bandwidth.

Network Requirements

Of the TANGO tools discussed in the previous section, all but BuenaVista require minimal bandwidth. Audio and video, on the other hand, involve real-time, two-way interactivity, which make them sensitive to network delay and jitter. In general, to provide effective multimedia content delivery, the network must possess consistent quality of service, minimal end-to-end latency, and no jitter.

In our experience, the three most significant factors affecting quality of service are: 1) reliable transfer rates, 2) minimal message delays, and 3) stable and symmetric network connections. Unfortunately, these characteristics are atypical of current commercial packet-based networks such as the Internet. To compensate for this, a dual-server architecture (Figure 3) with minimal bandwidth requirements was employed.

Lessons Learned

Overall, the courses were successful, that is, almost all of the students submitted their homework assignments, participated in e-mail discussions, completed a final project, and received a passing grade in the course. There were some difficulties, however, which caused the online lecturing process to be less successful than an actual classroom lecture course.

First of all, our experience indicates that current Internet bandwidth will not support real-time video. Although smart compression algorithms can sometimes compensate for poor Internet connections, we found that these were not enough. Audio, on the other hand, worked relatively well. In approximately five of the 30 lectures given during the fall semester 1997, a portion of the class was disrupted by low-quality audio caused by poor bandwidth or latency. Only once, however, was an entire class missed due to an Internet brownout.

During the fall semester, CSC 499 met twice a week on Tuesdays and Thursdays from 2:30 to 4pm Central Time. In retrospect, this was a less-than-optimal time of the day, since the Internet is usually quite congested during the mid-afternoon hours. Network traffic observations led us to believe that other times of the day would be better, so in the spring semester we changed the starting time of the class to 11:30am Central Time. This resulted in significant increases in available bandwidth.

Conclusions

Jackson State University course CSC 499, Programming for the Web was successfully taught distance-learning style using the TANGO collaborative software. The following conclusions may be drawn from this experience:

Future Directions

We learned much by this experience, but there are still many unanswered questions. For instance, during our site visits we observed students quickly losing interest in remote lectures delivered via one-way audio links. Why is this? Is it due to the relatively passive nature of the lectures? If so, the introduction of two-way audio should increase the perceived quality of the remote lectures. It will be interesting to see if this is the case.

Also, we may be underestimating the importance of visual cues and feedback mechanisms inherent in the learning process. The lack of eye contact between instructor and student may be hampering the overall learning experience. Unfortunately, given the network connection available to us in the fall semester 1997, there was little we could do to test this hypothesis. During the spring semester, however, the bandwidth between NPAC and JSU was typically in the neighborhood of 500 Kbps, which encourages us to continue our experiments with video.

In general, we must develop criteria for critically evaluating the inherent differences between traditional classroom lectures and remote lectures broadcast over a network. An understanding of these differences will drive the development process. For example, we need a reliable estimate of the cost/benefit ratio associated with real-time video.

As a direct result of our experiences, TANGO is currently undergoing rapid development. For example, the following enhancements to TANGO are being considered at this time:

Other improvements to the overall delivery system have been proposed:

It remains an important open question whether or not current Internet bandwidth will support two-way audio and video to the extent that students and teachers feel as comfortable with remote lectures as they do with traditional classroom lectures.


Figures


Figure 1: TANGO Control Application


Figure 2: TANGO WhiteBoard


Figure 3: Dual-server Network Architecture


Northeast Parallel Architectures Center

http://www.npac.syr.edu/users/trscavo/jsuspring98/overview.html
Last update:  Thu May 14 14:57:52 1998