J. Mark Pullen (email@example.com)
Department of Computer Science and C3I Center
George Mason University
Fairfax, Virginia, USA
The advent of the World-Wide Web has seen a tremendous expansion in use of the Internet for asynchronous teaching and learning, where the teachers place documents online and the learners access the information when it is convenient. By contrast, this paper addresses the role of synchronous Internet communication in distributed teaching and learning, where the teachers and learners are connected to the network simultaneously and communicate in real time. While the asynchronous mode clearly offers more convenience to participants, the synchronous mode also has much to recommend it. The comparison is roughly the same as that between correspondence courses and classroom teaching. This paper addresses the merits of the synchronous mode, both from a philosophical standpoint and from the experience base we have developed at George Mason University (GMU) in offering experimentally several different types of synchronous distance education. In ten semesters of experimental synchronous distributed education we have used a considerable variety of media with a wide range of students in several subjects. We have learned that the best teaching and learning environment is one that makes a mixture of media and information sharing styles readily available so the teacher can select at will, and move among them during a synchronous distance/distributed teaching session. The paper concludes with a list of research questions that are ripe for investigation, taken from the top of the sizable list of unexplored issues surrounding synchronous distance education. In the answers to these questions, we believe, lies the future of higher education.
distance education, distributed education, Internet synchronous sessions, multimedia networking
Table of Contents
The advent of the World-Wide Web has seen a tremendous expansion in use of the Internet for asynchronous teaching and learning, where the teachers place documents online and the learners access the information when it is convenient. By contrast, this paper addresses the role of synchronous Internet communication in distributed teaching and learning, where the teachers and learners are connected to the network simultaneously and communicate in real time. While the asynchronous mode clearly offers more convenience to participants, the synchronous mode also has much to recommend it. The comparison is roughly the same as that between correspondence courses and classroom teaching. This paper addresses the merits of the synchronous mode, both from a philosophical standpoint and from the experience base we have developed at George Mason University in offering experimentally several different types of synchronous distance education, where teacher and student participate simultaneously. I distinguish this from distance learning, where the teacher prepares materials in advance for asynchronous use by the student. I see synchronous and asynchronous modes as complementary parts of an overall set of methods that I refer to as distributed education.
Most of today's Internet-based teaching is limited to distance learning, based on student access to web-based multimedia documents. The approach uses network-accessed multimedia to expand on an old paradigm, the correspondence course. While that paradigm has a range of useful applications, its older form has not become the norm for education because it misses some important opportunities that are provided by the real-time communication with a teacher. With that interaction, the teacher can serve as mentor, answer student questions at the most "teachable moment", and provide up-to-date information that is missing from the "canned" version of the course. Moreover, the lack of interactive communication misses the opportunity for a learning mode that is in many cases the most effective of all: collaborative learning, where students learn by interaction with each other as well as the teacher. Distance learning based on retrieving Web documents suffers from the same general shortcomings as correspondence course distance learning. It can be improved by using intelligent tutoring to increase the level of interactivity. The most intelligent tutor available is a human teacher. Putting the teacher into the system with real-time communication generally results in an improved system for distance education.
In recognition of this situation, I have been experimenting with various media and teaching modes that support synchronous distributed education. This has proved to be a more difficult process, but a very enlightening one. Most of the difficulty stems from the fact that the Internet has far less capability to support real-time interactions among participants in the education process than it has to support fetch-and-read materials such as webpages. Even interaction between a student and a remote computer-based tutoring system is better supported than human-to-human communication. Facilities for "integrated services" that support real-time communication effectively are needed. However, the Internet technology community is hard at work creating and deploying such capabilities for real-time communication among groups of humans [RFC1633]. At GMU we believe that these will become widely available in the next decade, so we have persevered in our experiments, using such parts of the Internet as would support our work.
A second source of difficulty in working with synchronous Internet teaching
has been the need to overcome the preconceived notions of ourselves and
others regarding the most effective media and teaching modes for this purpose.
For example, it is often assumed that real-time video delivery is necessary
for effective real-time distance teaching. After investing considerable
time and energy in obtaining a capability for real-time Internet video,
I found that it had little utility for our educational needs. This experience
is described in more detail below.
Media of Synchronous Delivery
A discussion of distributed education necessarily begins with a brief
review of the media (and hypermedia) available for teaching through the
Internet. Given that learning is strongly affected by the psychological
state of the student, a major consideration for each medium is its cognitive
Plain text or even hypertext (text with a variety of fonts, faces, and colors) seems a very limited medium, but it has been the mainstay of textbooks for years, and forms the basis of nearly all intelligent tutoring programs. It is also the medium for which computers have been optimized over most of their existence. The most effective way to use text seems to be to generate it intelligently as part of an ongoing dialog, and in all cases to expose it as it is read to maintain an interactive mind-set in the student.
Hearing represents a second channel to the mind of the learner that generally has not been exploited in past networked computer-based education. Except in specialized cases such as teaching music appreciation, use of pre-recorded audio is mostly limited to evoking emotional responses (an example is the sound of seabirds and waves lapping at the shore to accompany a seashore scene). In our experience the most significant use of audio is to carry a real-time voice stream from an instructor, and to a lesser degree to allow spoken questions from students. The psychological impact of the teacherís speech can be greater than that of most visuals. Also some people are "auditory learners" who can gain more from hearing than vision under almost all circumstances. One-to-one audio is readily available in the Internet today in the for of "Internet telephone" software. It generally works well unless the Internet path between participating parties is congested. At least one of the packages, Speak Freely (http://ftp.ncu.edu.tw/OS/winsock/IRC/SpeakFreely/), also has a one-to-many capability. Many-to-many audio is harder to find; the Internet Multicast backbone (Mbone) [MaBr94] represents an effective, but resource-intensive, solution to the many-to-many audio channel problem, but even Mbone is subject to degraded performance due to congestion.
Much of the human race really does find "one picture is worth a thousand words". For them, the impact of simple drawings is very high, and that of photographic images is also great. Creating and transferring visual media is considerably more expensive in time and computer/network resources than would be the case for text, but it is generally worth the cost. Animated drawings can be particularly useful in motivating learning of topics with dynamic subjects, but they are also particularly expensive to create and transfer. A special case of graphics is the shared whiteboard, with a copy seen by each participant, who may also be able to write on it. Whiteboards may display either stored or dynamically generated graphics.
Often late-model computers (Pentiums and similarly powerful workstations) of considerable presentation power are interconnected by networks of moderate performance, such as most of todayís Internet. In this case delivery of large graphics can be unacceptably slow for synchronous teaching. A useful alternative is to cache or pre-fetch any large files at all locations, and display their contents under control of the teacher.
There are two distinct uses for video: pre-recorded sequences, and live instruction. Pre-recorded material has obvious applications to any topic dealing with the real world, from history to biology to the arts. In this case video represents another opportunity for synchronized files that can be pre-fetched. Live instruction is another matter. I believe a great deal of the emphasis on use of video for distance education is misplaced. I believe this derives from the fact that for many years the only available medium for distance education was "television teaching".
A great deal of effective teaching can be done over television, particularly in subjects that otherwise lend themselves to the lecture format. Also replay of video recordings can be an excellent way to bring the world into the classroom, whether the classroom is distributed or not. However, video consumes very large amounts of network resources (this is one reason television is so expensive as a means of teaching). Consequently, when its use is considered it is appropriate to ask what benefit is expected. In our experience, many times the answer is that video will add little or no benefit to a particular distance education course. I presented a complete undergraduate course via Mbone networked multimedia, and found that whether I am visible in the camera field has no discernible impact on the studentsí reception. In this case, it became clear that the "talking head" of the instructor simply added no value to the educational process, therefore I dropped the video and have found students remain satisfied with the course in question. I do believe that both live and recorded video are important media resources for synchronous distributed education. A good example might be providing a live demonstration in chemistry or biology accompanied by comments delivered using real-time voice. However I also believe that video, like all other media, should be used where it brings benefit commensurate with its cost, and not as a default.
Since the development of the Web, several generations of increasingly powerful display tools known generically as "browsers" have had a marked impact on the facility of presenting multimedia over networked computers. All of the Multimedia Internet Mail Extensions (MIME) types [RFC1521] can be displayed on a variety of platforms by competing browsers that interoperate on the hypertext markup language (html) standard. The result is a phenomenal leap forward in presentation capability for asynchronous distance education, particularly so in that the materials need only be created once for all platforms. The latest trend is to adopt browsers for real-time applications. The DARPA CAETI program [Gilfil97] resulted in several products that achieved successful teaching over browsers in various real-time paradigms, including our work at GMU in synchronous distance education (http://ito.darpa.mil/research/caeti/CAETI/index.html). One of our adaptations is directed browsing, where one browser chooses the URL to be seen by a group of other browsers (which can be anywhere on the Internet). Directed browsing has a range of applications, from simple slide shows to dynamic tours of Web sites around the Internet.
A Multi-User Virtual Environment (MUVE) is a distributed, computer-mediated and possibly multimedia system which supports collaborative activities with an appealing spatial, social paradigm. Users self-associate with a group in a "room". They may change rooms dynamically (and frequently do so). Everyone in a room receives the same information, which is generated by the actions of others in the room. All of the media described above are subject to educational application in the MUVE. Even with a simple text-based interface, a surprising amount of useful education is possible. In subjects where the material lends itself naturally to text (for example, literature and language) the text interface may prove to be all that is needed. As noted above, the availability of an audio capability greatly facilitates lecture teaching, and may also help with seminars and coaching. The graphic interface enabled by Web browsers adds a whole new dimension in the form of pictorial images, drawings, and animations. We have only begun to explore the rich combinations that are possible among these media. Particularly promising is the combination of audio with graphics, which allows a running commentary during guided discovery that is impractical with text-based commentary (where the student must continually be distracted from the material at hand to view the commentary).
Complementary Asynchronous Delivery
It is important to note that we also use the tools of asynchronous delivery,
e-mail and the Web. These form an important complement to synchronous delivery
in every case. A well-rounded distance education course needs these technologies.
However our experience at GMU shows they may not be enough to provide the
most effective education.
In my experience, the benefit from teacher-in-the-loop distance education is tied closely to collaborative learning styles, and derives from the psychological support for learning that is provided by group participation. The following (not necessarily exhaustive) list of synchronous teaching/learning styles can be supported in distributed education.
Experiences in Synchronous Internet Teaching
Shortly after joining the GMU faculty I was challenged by a colleague: "If you really believe that synchronous distance education is practical using the Internet, why are you not teaching that way?" In response to this challenge I began using the Mbone to teach my Senior undergraduate and Masterís-level courses in Computer Networking, as an experiment in distance education. The media available were audio, video, and a whiteboard that could post text, handwriting, annotations, and pre-stored postscript format slides. The process involved presenting the course to students in my classroom using a workstation and projector displaying slides and annotation on an Mbone whiteboard. There was also an Mbone video link using a camera fixed on my position by the workstation [Pullen96]. A student who worked at a facility about twenty miles away that had Mbone access volunteered to participate in the first such course. The experiment proved so successful that another student who worked at the same location sought to participate, because he felt the direct-to-desktop delivery allowed him to learn better than sitting in a noisy classroom. During this course that I realized I was spending very little time in front of the camera. I asked the distant students if I needed to be on camera more; they replied that it was unimportant to them. In later courses I disconnected the camera and had no complaints.
A Larger Undertaking
After a year of experiments over Mbone, I was asked by my college to try "real" distance education. GMU purchased equipment for distance delivery, which I used to teach my networking elective to a class at the Manassas, Virginia campus simultaneously with in-person delivery at the Fairfax campus where I normally teach. The equipment consisted of a Xerox LiveBoard and Intel ProShare at each location. The LiveBoard is a rear-projection display about six feet across the diagonal, with a sensitive screen that can be used as an overlaid entry tablet. It is provided with software called LiveWorks that only supports point-to-point connection over the Internet unless a special bridging unit is leased or purchased. It functions as a two-site whiteboard, and can import slides from Microsoft PowerPoint. (GMU has dedicated Internet links between its campuses so network congestion is never a problem.) ProShare is a video teleconferencing system that runs in an Windows/Intel computer with a special-purpose video compression/decompression board. Our ProShare runs over ISDN lines and has applications sharing software that we do not use. This combination was used for two semesters to teach up to fifty students located with me and another five to ten at the distant site. Where my students and I had supported the Mbone connection, GMU classroom support took over the LiveBoard/ProShare. This was their first experience supporting live distance delivery and we had many problems. The course got delivered, but the students were not pleased with the amount of time lost to non-functional delivery systems. As for video, the experience with Mbone was repeated: students did not care if I was on camera. In fact, I found the video more useful than the students did, because I could tell if a class was present and attentive at the other campus.
Desktop Delivery for Professional Education
One of my students who had been helping with all of these experiments set out to create a low-cost distance education environment as a Masterís project. The result was so promising that he has since commercialized it. Using a Windows/Pentium computer with a sound card and 28.8 kilobits per second modem, his "PPClassroom" [Magi97] system links up to twenty desktops with synchronized PowerPoint slide files and delivers voice and annotations from the teacher. It supports text-mode questions and comments from the students, and text broadcast by the teacher. The system also features a recorder so that missed classes can be played back at will over the Internet. I used this system for two experimental pilot professional education short courses in networking during school year 1996-97. The students were working technical professionals. Communication was via the commercial Internet, which posed unexpected problems with firewalls until we found ways around them (including dial-up modem links). I used the text broadcast frequently to send out questions, in order to send from student responses whether they were following me. The highlight of this experience was teaching the final lecture successfully from Ramstein Air Base in Germany during a CAETI trip. Now GMU is undertaking a professional education course of nine one-month blocks in Network Engineering, taught by a team of six faculty. Our students work in local industry and their employers value the time saved by learning at their desks rather than commuting to class (http://bacon.gmu.edu/nec).
Classroom and Desktop Delivery for Graduate Students
GMU had students at both of its other campuses (Arlington and Manassas, Virginia) who wanted my Masterís level course in Computer Networking Systems. However the LiveWorks/ProShare system would only support one other campus, and I did not have time to teach twice. Therefore LiveWorks was replaced with PPClassroom and the ProShare video was dropped. Now both campuses could participate, as could students at home or office, and all classes were recorded to an Internet-based server. Lack of video has bothered the students very little, although it does mean that I must periodically direct a question to the other campuses to be sure they were "tuned in". Now that the course is completely Internet-based, the students gave distance education high ratings. I am using the same system this semester, with good results, and expect to do so for the foreseeable future.
Mbone Delivery to Europe
In the DARPA CAETI program GMU undertook to provide Internet Literacy training to teachers at four U.S. Department of Defense school complexes in Europe. This was done to prepare the teachers to use CAETIís educational software products. To do this we adapted an existing course which was taught by my colleague Brad Cox over cable TV. We captured his broadcasts and fed them into the Mbone. Because of schedule difference due to time zones, we recorded the classes for delayed playback. We also mailed videotapes to the schools. The tapes turned out to be much more popular than Mbone, because they could be taken home. However the most popular part of this course was the Internet-based project, which consisted of using various tools (telnet, FTP, listserv, http authoring, etc.) and submitting the result over the Internet. The Internet user-level technologies were very popular with the teachers. We believe one reason for this was because they provided a way to reduce the isolation the teachers felt outside their own culture. In later offerings of the course we adapted the material to focus more on needs of the classroom teacher, and employed Speak Freely Internet telephony and directed browsing. As we adapted the content and presentation technology to the needs and learning style of the teachers, their stated appreciated of the course continued to increase [SpPu97].
MUVE Delivery to Europe
A second course for the teachers in Europe was much more experimental.
We taught C++ programming to high school computer teachers at the same
four U.S. Department of Defense school complexes in Europe. These teachers
knew how to program in the Pascal language, but the C++ language was new
to them. My colleague Eugene Norris taught this class using a MUVE. Initially
the MUVE was text-based but as time went on we added browser-based interfaces
from the BioGate project (http://bioinformatics.weizmann.ac.il/BioMOO/BioGate).
Later we used CoolTalk (http://search.netscape.com/comprod/products/navigator/cooltalk)
to provide a voice link. Most of the teachers never became completely comfortable
learning in the MUVE, but accepted it as the only way a geographically
dispersed group could hope to study a subject that was not taught locally.
Subsequently we provided a C++ laboratory to students at Aviano American
High School in Italy using the same configuration. These students were
studying from a "distance learning" course based on Lotus Notes. Unlike
the teachers, the students adopted the MUVE enthusiastically and scored
noticeably better than their peers who did not use the MUVE (unfortunately
the sample was too small to show statistical significance) [PuNo98].
The media, modes, and teaching experiences described above make a strong case for the value of synchronous distance education. As described above, a rich variety of tools exist for this purpose.
The thread running through all of these cases is that distance education works best when the technology is tuned to the needs of the topic, the skills of the teacher, and the learning style of the student. It is also important that the technology be robust and adapted to the technical sophistication of the student. It follows that the ideal distance education environment is one that makes a mixture of media and information sharing styles readily available so the teacher can select at will, and move among them during a synchronous distance/distributed teaching session. It also follows that teachers must work to develop facility with the tools, and learn to employ the technologies to meet the needs of the students. A corollary is that distance education is more work for the teacher than conventional classroom teaching. While the student benefits greatly from increased accessibility, there is a price to be paid in teacher preparation and presentation effort.
Based on the success of our integrated MUVE with Web browsers and other tools, we are working to expand this paradigm. We are integrating a full suite of multimedia tools under a Java executive with a synchronizing server that also provides admission control. Our concept is that all tools will be available dynamically upon one or two mouse clicks, within the framework of a MUVE. This new environment will be both a conferencing space and a seminar room. We look forward to being able to teach online without the encumbrance of having to set up and operate each tool separately.
Enlightening though our synchronous Internet teaching experience has been, there are many unanswered questions. Potential benefits to the student indicate strongly that distance education will be a growing activity for many years to come. In order to expand distance successfully, we will need to answer questions such as:
[Gilfil97] Gilfillan, L., "CAETI Program Evaluation Results", Computer Aided Education and Training Initiative Meeting, George Mason University, June 1997
[Kozma91] Kozma, R., "Learning With Media", Review of Educational Research, Summer 1991
[MaBr94] Macedonia, M. and D. Brutzman, "Mbone Provides Audio and Video Across the Internet", IEEE Computer, April 1994
[Magi97] Magideas Corp., "PPClassroom 97 V1.0 Manual", Reston, VA, 1997
[Pullen96] Pullen, J., "Synchronous Distance Education Via the Internet", Proceedings of Frontiers in Education í96, IEEE, Salt Lake City UT, November 1996
[PuNo98] Pullen, J. and E. Norris, "Using A Multi-User Virtual Environment As A Synchronous Teaching Tool", Proceedings of the Winter Simulation Multi-Conference, Society for Computer Simulation, San Diego, California, January 1998
[RFC1633] Braden, R., D. Clark, and S. Shenker, "Internet Integrated Services", Internet Engineering Task Force RFC1633, June 1994
[RFC1521] Borenstein, N.and N. Fried, "MIME (Multipurpose Internet Mail Extensions", Internet Engineering Task Force RFC1521, September 1993
[SpPu97] Sprague, D.and J. Pullen, "Integrating the Internet and Curriculum:
A Web-Based Course for Teachers", National Educational Computing Conference,
Seattle WA, July 1997