MULTIMEDIA AND SOME OF ITS TECHNICAL ISSUES. SHOUSAN WANG.

Full Text: COPYRIGHT 2000 Westwood Press, Inc.

INTRODUCTION

Due to the rapid booming of technology, the practices of our classroom teaching and learning have been deeply impacted. Traditional media technologies can no longer meet the needs of our classrooms' teaching practices and learning processes, as the direct result, and they have been rapidly replaced or are going to be replaced by multimedia and its technology. Multimedia and its technology, an increasingly popular instructional delivery system, provide a learning environment that is self-paced, learner-controlled, and individualized. The existence of multimedia and use of related technologies is going to become a common part of our classroom teaching and learning activities. Few would dispute the importance of making instructor and student aware of the rapidly advancing technologies of multimedia and information handling which is in the process of transforming our classroom practicing. Then what is the multimedia? What kind of technology does it imply? In the past multimedia has been referred to the use of several media (slides, film, audio tape, etc.) simultaneously in a coordinated manner. Today computers integrate these media and others (video, text, graphics, and sound) to allow interaction and control by the learner (1). According to Gayeski, multimedia can be defined using the following description:

      "Multimedia is a class of computer-driven interactive communication
   systems which create, store, transmit, and retrieve textual, graphic,
   and auditory networks of information" (1).

Embedded in the above definition are three elements: the computer, graphics and networks, which when combined provide a new and powerful technology. However Gayeski pointed out that not all components of the technology need to be present for multimedia to occur, i.e. text-only applications such as electronic mail also qualify as multimedia. The term multimedia could therefore include electronic mail or a complex configuration of computers, interactive video CD-ROM, camcorders or mixers. Because many of these technologies have existed before, we can learn from past research in their implementation. This means that previous television or previous computer research could bring valuable insights to the field of multimedia in the classroom (1).

As Gayeski's definition is very broad in light of the three basic elements, discussing them in detail is out of the scope of this article. However for the discussion purpose three typical technologies have been selected in this article as models to present them. They are: computer-assisted instruction (CAI); video-on-demand; integrated services digital network (ISDN). They represent the roles of which computer, graphic and network are playing in the multimedia and its technology respectively. They are probably the three of most used technologies in multimedia system today. Thus it is critical for students and faculties, of course including many media professional themselves, who are used to or familiar with the traditional media environment, to understand their applications, advantages and implications behind the technical terms. It is believed that once faculties or students are able to benefit from these multimedia technologies, they will use them anxiously. As media professionals, it is very important to realize that the technologies are there, and what they need to do now is to convince their customers: faculty and student, that these multimedia technologies, applications, methods and equipment are designed for them. They are the beneficiaries in the use of multimedia technologies.

One has to admit that there are still some faculties and students who claim that they:

1. are not so sure the new technologies will improve their teaching practice and/or student's learning skill, even many studies had been conducted and pointed out that the new technology such as computer-assisted instruction are as effective as other traditional technologies (2),

2. are afraid that the new approaches and equipment are too complicate for them to set them up or operate tlhern during the regular class schedule,

3. do not have enough time during their very busy schedule to learn how to operate them,

4. concern that it may divert student's attention from the content/material of the curriculum.

5. are worried about not being able to give definite answers to some questions raised by students because the instructor does not have enough time to think about the live materials and information brought in,

6. are not able to control the pace of teaching plan.

This list can be very long. The truth is that these concerns are understandable but as many researchers have indicated it is not necessary. Once one is familiar with the new technologies and equipment, and once students' learning has remarkably improved, their attitude will change dramatically. As a matter of fact, how to make use of these technologies correctly and properly to speed students' classroom learning and to improve faculties teaching effectiveness and efficiency is another frontier topic facing most media professional persons.

One also should realize that the technology itself, such as multimedia, does not teach; it is, however; the vehicle for instruction set by the curriculum. The aim of this article is trying to introduce several most used technologies of multimedia, discuss their advantages and explain some related applications issues. It is our hope that some of faculties' and students' concerns mentioned above will be or at least partially eased.

INTEGRATED SERVICES DIGITAL NETWORK (ISDN)

Integrated Services Digital Network (ISDN) is a set of standards, or engineering design specification, which is heard very often these days when one is developing multimedia systems. Technically speaking, ISDN is a dial-up digital transmission service supporting transmission of audio, video, and text data over standard copper telephone wires or fiber optic cables (3). It will permit anyone to attach any innovative device to it as long as it abides by the network's protocols. Advantages of ISDN over analog transmission are the ability of one phone line to support up to three simultaneous, separate conversations (phone, fax, computer), and increases in clarity (4). Comparing with other data transmission options, such as asymmetric digital subscriber lines (ADSL), high-speed digital subscriber lines (HDSL), and cable modems, ISDN is the most practical solution for high-speed remote access. It can help to achieve equity, access and interactivity regardless of distance. From a user's point of view, the advantages of ISDN should also include its reliability, cost, flexibility, scalability, standards, and manageability (5). It does provide unique opportunity for instructor and student to access many instructional materials and information at the same time from many different locations and which is impossible to be obtained using traditional media technologies. Briefly speaking it is interactive and essentially it is an extension of good classroom practice in term of educational purpose. Today, more and more educators around the country are looking at ISDN's possibilities for improving both the quality of education and access to educational resources. ISDN's capabilities have the potential to affect many areas of education, ranging from curriculum development to teacher in-service. It could impact school in two ways: as a resource for teaching and as a tool to contribute to the development of teaching skills (6).

However, it should be pointed out that ISDN is not a broadcast television system, nor is it a video production. As we know, broadcast television needs at least 40MB transmission capability. Although ISDN can provide three different level services in light of its transmit speed; 64kb, 128kb and 384kb depending upon the need of users and its availability. It is only achieved the maximum of one hundredth of television standard. The key technology used in ISDN (many other systems use it also) is called digital compression technology. A video signal from a video camera (or any other video resource) is fed to an encoder at transmission site. A piece of computer software within the encoder digitizes and reduces or `compresses' the total signal content. This digital signal is then transmitted to a decoder at the receive site which reconstitutes the video signal (7). The whole aim of the compression is to dramatically reduce the bandwidth requirement, and thus, the users' costs. Because the involvement of the compression technology, though one will notice that the pictures on the monitors are seem slightly jerky, it does meet our needs very well. It will probably prove to be most effective when used in conjunction with other delivery systems - text, correspondence, fax, computer, audio and videotapes, etc. ISDN can also be networked with Internet. In summary, there are several issues, which need to be considered when one plans to use ISDN services: (a) service availability; (b) service level offered; (c) service level needed; (d) installation fees; (e) tariff structure; (f) equipment needed; (g) installation and configuration requirements (8).

Today, educators are dealing with increasing class size, discipline problems, limited funding and cultural diversity. Rural schools face exceptional challenges in helping their students prepare for a rapidly changing world. ISDN is one of the tools, which can help teachers overcome these challenges by providing them with additional resources such as teacher training, educational research, and instructions for students (9).

The figure one is simplified block diagram of an ISDN system.

[Figure 1 ILLUSTRATION OMITTED]

VIDEO-ON-DEMAND

There is a growing interest in supporting digital video applications, such as video-on-demand, over local area networks. These applications fall into two main categories:

1) stored-video applications which involve the sharing of digital video information stored in a server through a local area network, and

2) live-video applications which involve the use of the video medium for interactive communication among people, as seen in video conferencing and collaborative computing applications (1).

Video-on-demand technology opens the door for many multimedia applications via the Internet that was impossible without the process (10). One calls it as "the Next Generation Internet (NGI)" (11). The system is identified as being of most benefit to students in individual study of course material (12). As all of us know, when video first came to the Web, it was necessary to download the entire video file before beginning to play it. As a video file can easily be many megabytes, and bandwidth was worse then than it is now, those working in this area sought a way to avoid making the end user wait a long time for a video file (10). The following description is how the system works:

      "Instead of downloading the file in its entirety before playing it,
   streaming technology takes a different approach: it downloads the beginning
   of the files, forms a buffer of packets, and when an appropriate buffer is
   reached, the client player plays back the packets in a seamless stream.
   While the viewer is watching, it downloads the next portion, etc., until
   the entire file is played" (10).

Meanwhile the system allows one digitally encoded video to be used concurrently by many instructors and students, solving the problem of limited viewing facilities. The flexibility of digital video also enables new ways of presenting comparative materials as well as providing more efficient ways to undertake typical student assignments. For example, it facilitates repetitions of a single scene for in-depth analysis (12).

Technically, video-on-demand is a computer based video distribution system that stores video (pre-recorded or live) in compressed digital form for various uses. It makes use of the existing computer network (LAN) to distribute video document or live interactive video on demand. The heart of the system is so called `Video Server(s)'. For instance, it functions like a digital videotape player which will deliver full screen, television-like quality video (25 to 30 frames per second) right to a desktop computer. If needed, the signal can be fed through a computer to a data projector, such as LCD projector for a large number of audience site. Because the characteristics of digital video files and traffic differ substantially from those encountered with data applications, the conventional file servers are not well suited to support video servers over LAN. The main piece of software resides on each desktop computer accessing this system. The system administration software resides on video server, which will not only hold and manage video files (MediaHawk, Concurrent Computer Corporation), but also provide configuration options for the server, system performance monitoring and diagnostic features (MediaHawk, Concurrent Computer Corporation). The video-on-demand system consists of:

1. video resource(s): it could be any analog video signal,

2. analog-to-digital converter and encoder: it digitizes and encodes the analog video signal,

3. video server: it compresses and stores the encoded signal,

4. LAN: local area network,

5. system management/administration: it provides administrative control for the whole system,

6. end users: it is the user(s) who have access to the video files when they need.

The advantages of a video-on-demand system can be summarized as follows:

1. it allows a number of people to be able to view a particular video file from a server simultaneously, while fully retaining their other network functions,

2. it provides a networked vlideo communication and presentation system for the organization,

3. it reduces dramatically the cost of multi-point video conferencing,

4. it is able to use multimedia workstations linked by LAN or WAN providing computer-supported collaboration.

The figure two is simplified block diagram of a video-on-demand system.

[Figure 2 ILLUSTRATION OMITTED]

COMPUTER-ASSISTED INSTRUCTION (CAI)

Computer-assisted instruction (CAI) is a much more abroad concept comparing with previous two, CAI is not a new concept. Its roots can be traced to at least forty years ago, so called machine-delivered instruction. Today, thanks to incredible advances in both engineenng and electronics, CAI based on the small, versatile microcomputers is readily gaining acceptance as both instructional and administrative tools in educational environment. Then what is CAI? The literature related to CAI contains a variety of definitions for the concept. Some authors suggest that any instructional use of the computer is CAI, while others are much more specific in regard to the types of instructional applications that can be considered as CAI. Inherent to all definitions, however, are the concepts that the computer can be helpful in delivering instructional materials to students, and that the term CAI itself encompasses several different learning strategies. For an example, Frenzel described and defined CAL, as (13):

      "The process by which written and visual information is presented in a
   logical sequence to a student by a computer. The computer serves as an
   audiovisual device. The students learn by reading the text material
   presented or by observing the graphic information displayed The primary
   advantage of the computer over other audiovisual devices is the automatic
   interaction and feedba,ck that the computer can provide. Multiple paths
   through the course material can be take, depending upon the individual
   student's progress".

Today, CAI has been utilized in almost every educational field at various education levels. One should be aware that CAI has been changing and will continue to affect and influence both curriculum content and educational instruction delivery methods. Although CAI has been changing and will undoubtedly, continue to change the way teachers teach, it is not intended to replace teachers--even partially. Perhaps more than anything else, these trends indicate the need not only for careful planning in the adoption of CAI, but also for the recognition of CAI as a teaching tool not as a teacher substitute (14).

Like other educational media, a CAI program is composed of many phases, each of which may be critical. A well-desi gned program motivates the learner, informs the learner of the objectives of the lesson, reviews prerequisite skills required for the student to be successful in the lesson, presents well-organized instruction, evaluates progress frequently, provides adequate feedback, allows for adequate practice, and evaluates final performance of the student and of the lesson itself (15). Thus effective CAI is based on the principles of instructional design.

A piece of well-designed CAI program will not only let students take its maximum advantages, but also implement most of the Gagne's events of instruction better than the traditional instruction programs. The Gagne's events of instruction should include:

1. Gain attention: The attention of students is gained by introducing rapid stimulus changes. Studies indicated that effective CAI programs use the capabilities of the computer to amplify information, by varying the use of features such as colors, print size, text display rate, and others (16).

2. Inform the learner of legion objectives: When learners comprehend the objectives of instruction, tlhey will acquire an expectancy that normally persists throughout the time learning is taking place and that will be confirmed by the feedback given when learning is completed (17).

3. Stimulate recall of prior learning: According to the Gagne's theory of instruction, before engaging in the instruction, the learner is asked to recall some filings previously learned.

4. Present the stimulus material with distinctive features: Any stimulus must have its distinctive features clearly delineated.

5. Provide learning guidance: This involves making the stimulus as meaningful as possible. In general, use concrete examples of abstract terms and concepts, and elaborate each idea by relating it to others already in memory.

6. Elicit the performance: The learner is required to demonstrate the newly learned behavior to show whether or not the learned capability has been stored in long-term memory.

7. Provide informative feedback: The learner is informed of the degree of correctness of his/her performance.

8. Assess performance: To ensure that the learner has learned the new capability, it is necessary to require additional instances of the performance. Assessing performance serves two functions: establishing whether or not the new learning has reasonable stability, and providing additional practice.

9. Enhance retention and transfer: Providing additional practice with a wide variety of instances is likely to increase retention of all learned capabilities.

CONCLUSION

As multimedia combines the technology of video and computers, one of the most important advantages is that it may offer a unique environment for interactivity, learner control and student interest and motivation. It should be indicated that the quality of an instructional multimedia system depends on the integration of technology, information, and personnel. Merely piecing together existing media components cannot solve many problems associated with the development of a quality instructional system. The multimedia and its technology are still on its developing stage. It is believed that multimedia and its technology with its potential brilliant prospect is impacting our classroom teaching and learning, and it will continue to do so. Let us use John Sculley's description of multimedia as the end of our discussion:

      Imagine a classroom with a window on ali the world's knowledge. Imagine
   a teacher with the capability to bring to iiife any image, any sound, any
   event. Imagine a student with the power to visit any place on earth at any
   time in history. Imagine a screen that can display in vivid color the inner
   working of a cell, the births and deaths of stars, the clashes of armies,
   and the triumphs of art. And then imagine that you have access to all of
   this and more by exerting little more effort than simply asking that it
   appear. It seems like magic even today. Yet the ability to provide this
   kind of environment is within our grasp (6).

REFERENCES

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Direct Reprint Requests to: Shousan Wang, PH.D. Central Connecticut State University 1615 Stanley Street PO Box 4010 New Britain, CT 06050-4010

SHOUSAN WANG, PH.D. Central Connecticut State University