Northeast Parallel Architectures Center Syracuse University 111 College Place Syracuse, NY 13244 |
Department of Computer Science Jackson State University P.O. Box 18839 Jackson, MS 39217 |
* Author for Correspondence: bernhold@npac.syr.edu |
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.
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, Programming for the Web
The first offering of Jackson State University (JSU) course
The goal of
http://www.npac.syr.edu/projects/cps606spring98/for a recent offering of
Students in
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.
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
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: 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
During the fall semester, Conclusions
Jackson State University course
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
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.
Northeast Parallel Architectures Center