Major Technologies for Delivering Distance Education
Anne Savage and Terri Buckner
Old Dominion University
Higher education institutions involved in distance learning depend on a wide variety of transmission technologies that are either analog or digital. Analog systems transmit signals in the form of electrical waves while digital devices transmit information in bits and bytes. Most telephones and televisions are analog devices while computers operate using digital technologies. The majority of distance learning networks utilize a combination of these technologies with interaction between students and instructor occurring in either a real-time (synchronous) or delayed time (asynchronous) format.
The vast majority of distance learning networks utilize video signals to deliver programming to students who may be located at educational sites, hospitals, corporations or at home. Some of these networks broadcast materials presented in a videotape format on satellite systems to a specialized site, sometimes in combination with cable or local PBS stations that deliver the programming to the home. Most often these courses have been Apre-produced@ by colleges, universities or PBS stations with funding from outside sources such as the Annenberg Foundation. Nationally, many community colleges utilize these courses as part of their program offerings. In Virginia, Northern Virginia Community College has an extensive network that builds upon these courses, while nationally, Dallas County and Rio Salado Community Colleges enroll thousands of students using this format. In each of these cases, it is not expected that the student would interact with the instructor during the class broadcast time. However, students are expected to travel to an educational site for testing or group discussions and usually the pre-produced videotapes are supplemented with intense study guides that do require interaction--often by mail and sometimes by e-mail-- with the instructor. Other examples of this model would be the British Open University program and courses licensed by PBS for their educational partners through cable channels. Governors State University also utilizes this format in the delivery of their courses and programs.
In this model, the courses offered have been designed and produced in a broadcast medium format utilizing teams of faculty experts, television producers and instructional designers. There is a substantial range of quality, and some courses have cost up to a million dollars and/or taken more than a year to produce.
Other satellite video networks operate in a synchronous format meaning that students at disparate sites are tied to the instructor through a phone bridge for in-class interaction. Typically, students convene at a site equipped with a satellite downlink and a designated room providing television monitors, videotape recorders, and interactive phone lines is utilized. Typically, this model is an extension of an on-campus course with students also located at the home campus. While the distance students can talk among themselves and interact with the instructor, the instructor cannot see the students. In this setting the students often take advantage of the peer mentoring and student to student collaboration that this distance learning environment encourages. Training for faculty to function successfully in this environment is essential. California State University - Chico and Old Dominion University=s TELETECHNET program both utilize this model to deliver baccalaureate completion programs and more than 30 institutions participating as members of the National Technological University (NTU) deliver graduate engineering courses in this format. In the latter example, however, it is reported that students are not required to interact with the faculty member during class time and the majority of these students view the recorded videotapes at a time more convenient to them. One of the advantages of this system is the ability to increase the network by adding sites through the installation of satellite receivers making the delivery of programming very cost-effective. It is also routine to be able to offer two or more simultaneous courses using this technology. Other Virginia institutions offering courses using broadcast technologies include: University of Virginia, Virginia Tech, Norfolk State University, Virginia State University, and Virginia Commonwealth University.
Some distance learning classrooms support two-way video communication. These networks are usually built upon land-based systems utilizing phone lines for transmission of the signal. The video signal is significantly compressed, transmitted and received by CODECs that code and decode the video message. Usually these networks consist of fewer locations, providing effective two-way video for up to eight sites simultaneously. Individual CODECs are required to encode and decode each channel of programming and both video and audio signals must be bridged to allow seamless transfer of information.
The quality of the signal is dependent upon both the available signal bandwidth. Generally, a lower quality (but adequate) signal can be sent using an ISDN line with the quality of the video signal improving significantly if a fractional T-1 line is used. Net.Work.Virginia uses an ATM (Asynchronous Transfer Mode) network which provides enough bandwidth to allow two-way video-conferencing to achieve the highest quality picture currently feasible. However, the costs associated with leasing ATM lines from telephone companies, the necessary equipment, and network management fairly expensive. The Virginia Community College System shares courses among the various campuses, and Virginia Tech and the University of Virginia plan to utilize this technology for the delivery of their video-based graduate engineering courses beginning in the fall. Old Dominion University will be developing a virtual classroom through the connection of the three higher education centers with the Norfolk campus allowing faculty to originate a class from any location while students can elect to attend classes at a location that is most convenient to them. Also in Virginia, Radford University offers several courses in Roanoke and like several other public school systems, Hampton Public Schools connects four of their schools for teaching advanced level high school classes using a compressed video network. This technology is also widely used by the military community. The United States Navy has created a virtual schoolhouse by connecting major naval training facilities across the country using this technology; and the U.S. Army's Teletraining Network (TNET) uses this technology to provide two-way video connectivity to numerous Army and Air Force sites. The states of Kentucky and Tennessee also have compressed video telephony networks connecting institutions of higher education within those states. While the cost to transmit signals is very cost-effective, the equipment used to establish and expand the network can be expensive if multiples sites are required or the number of courses to be delivered extensive. The strongest growth in the distance education market has been in the use of the computer with Internet access to provide anytime, anyplace (asynchronous) learning. For content that can be covered asynchronously and primarily through text and small graphics, the Internet is an inexpensive and widely accessible distance learning technology for learners who want to participate in educational activities from home. The Internet can also support synchronous activities, such a chat rooms and desktop teleconferencing. Christopher Newport University makes available a baccalaureate program in Criminal Justice and Virginia Tech offers a graduate program in Political Science and one in Health and Physical Education. Several Virginia colleges offer a broad array of courses on t he Internet and some, like George Mason University offer courses in conjunction with electronic publishers such as University On Line. Nationally, the University of Phoenix is well-known for its on-line programs.
One of the serious limitations of the Internet as a distance learning technology is its ability to encode scientific symbols. In a mathematics course for instance, equations that use radicals must be treated as graphics, and for students to create their own equations they must have knowledge of how to use special editing software. Also, courses which depend upon the use of multimedia are restricted by the amount of available bandwidth at any given time. Available bandwidth fluctuates widely depending on time of day, number of users logged into the server, weather, and other issues which cannot be controlled by the university or the student. Often, the time needed to download an audio or video stream can tie up a student's home telephone line for an hour or more. Although there is no known research that draws a correlation between download time and instructional validity, commonsense says that some type of relationship must exist. Undoubtedly, new technologies, such as cable modems and improvements in compression technology, will evolve to mitigate these problems.
In Virginia, colleges and universities have initiated several pilot projects to test emerging technologies. At the present time, each project is course specific and limited in scope. Some examples of these projects include offering two-way video courses in a synchronous format to the desktop by utilizing broadband connectivity using either ATM technologies through Net.Work.Virginia or cable modems. Another project in the planning stage will test the emerging ADSL (Asymmetric Digital Subscriber Line) that lets high-speed modems work over existing telephone lines, giving users more bandwidth. Other projects are utilizing ISDN connections to the desktop computer utilizing teleconferencing software for two way video and teaching English composition in a synchronous format using only voice and data interactivity. Still others have created Web-based courses with audio and video streaming built into the design and offered on a campus broadband network.
In summary, a great deal of activity is occurring on college and university campuses to test new and emerging technologies while expanding networks that are built upon more reliable formats. Most of the Virginia distance education efforts are taking advantage of multiple communication formats, merging the ease and accessiblity to information that the Internet offers with video-based networks, while incorporating video-based instruction into the courses delivered on the Web. As the improvements in technology continue to rapidly evolve, Virginia institutions will be well positioned to incorporate them into their distance learning efforts.
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