Educational Technology & Society 5 (1) 2002
ISSN 1436-4522

Distributed and Online Distance Lecturing Environment
(The Virtual Blackboard Project)

 

Yiannis N. Sagias
Research & Development Department
EXODUS S.A., 6-10 Farantaton
Athens, 11527, Greece
ysagias@exodus.gr

 

ABSTRACT

Computers and networks are increasingly able to support distributed collaborative multimedia applications. In fact, the growing interest in distance learning reflects the awareness that these technologies could support the broad, complex interactions at the heart of instruction. However, designers of such applications face many challenges. For example, how effective is a flexible design that lets a class form its own practices? To what extent should conventions be designed in or promoted through training? Although researchers have begun to explore these issues, longitudinal studies are rare. In this paper, we look at these issues using Virtual Blackboard, an extensible system that provides a wide range of interaction capabilities. In Virtual Blackboard we based development on the concept of the ISO/TEC standard MPEG-4, which was providing the specifications that would make the development of a sophisticated, fully interactive, common for all applications, environment possible.

Keywords: Distance lecturing, Distributed environment, Online learning , Three-tier architecture


Introduction

Networked computers are increasingly able to support distributed, real-time multimedia presentations, including live audio, video, and feedback channels. A key application domain is distance education. Although controversial when seen as a replacement for standard classrooms, distance education can provide advantages when classroom attendance is not possible, or for students who wish to participate more casually.Distance learning has a long history. Correspondence schools developed over time, culminating in the highly respected Open University courses, which often mix postal correspondence and live sessions. Several distinguished Universities, including Stanford (DiPaolo, 1998) and the US National Technical University (NTU) (Dankel, 1997), have offered correspondence degrees for over 15 years, while more recently, the Internet and Web have facilitated distance learning (Carswell, 1997; Lawhead et al., 1997).

Many systems address intermixing multiple streams of information in synchronous and asynchronous environments. Virtual Blackboard (VB), like the Xerox PARC Colab system (Stefik et al., 1987) captures real-time interaction using a distributed object system in a tele-presentation setting. VB has to address the timing variability of multiple streams of data, (Manoharm and Prakash, 1995) as well as handle synchronous collaboration with variable latency. This compensation for latency allows VB to avoid the problems reported for the PERSYST system (Ginsberg et al., 1998) in dealing with content change events.

Computer applications for distance education gradually fall into the following categories:

  • Multimedia CD ROMs
  • Web courses
  • Internet Relay Chat (IRC), Object Oriented MUD (MOO) and Multi-User Dungeon (MUD), Email and List Servers
  • Audiographics, Institutional Television (ITV), and Videotape
  • Teleconferencing, Audio/Video Conferencing, and Computer Conferencing

Even though widely used in education, these applications share a major disadvantage: they cannot be used together in a common environment to obtain a high level of interactivity for all applications. It is possible for a remote user to follow a live lecture (streaming video application) and simultaneously navigate to Web page (web browser application), both applications can appear in different windows on the same screen. It is not possible, however, to drag an object from the “lecture window” and drop it into the Web page.  This is due to the fact that the two applications are not interconnected through a common protocol, none of these categories can support online and off-lecture, heavy multimedia content manipulation, properly structured and archived allowing sophisticated information retrieval. The recent ISO/TEC MPEG-4 standard, although not finally implemented, hasprovide a concept that could make the development of a sophisticated, fully interactive, common for all application, environment possible.

 

Objectives of the system

The objective of Virtual Blackboard is the creation, testing and dissemination of a lecturing environment, based on MPEG-4 concept, which would allow users to interact with scenes. A scene would be characterized by the interconnections and attributes of media objects presented. For example, a scene may contain streaming video, a web page, a document or any other multimedia object. According to attributes assigned, clicking an object (say a telephone) creates a resulting effect (i.e., a communication session is starting between two users). Within VB, it is possible to:

  1. Simultaneously handle interconnected heavy multimedia objects (hereafter called media objects) such as audio, video, images, text, 3D graphics, etc. All these objects may appear on screen and the remote user is able to manipulate them (drag and drop, rotate, move everywhere on screen, etc.).
  2. Support the organising, design and presentation of a remote lecture through special tools that will be developed. The lecturer will be able to:
  • Select and organise multimedia material (content, kind of material, etc.) for efficient archiving and retrieval.
  • Setting up the lecture in terms of scenes where each scene is an interactive session between the user and the media objects.
  • Assign properties to multimedia objects to determine the way users will interact with them.
  • Control the flow of the presentation (what to show next, in what way, etc.).
  1. Support student activities. The student will be able to:
  • Interact with objects on the lecture screen according to privileges and attributes set by the lecture organiser. For example, while watching the lecturer through streaming live video, the user will be able to handle the video in usual ways (pause, back, slow motion etc.).
  • Tag media objects and archive parts or all for reuse.
  1. Support multiple lecturers from different locations (distributed lectures). There will be either one centre to control the flow or the control will pass from the one lecturer to another.
  2. Support high bandwidth or low bandwidth infrastructure.
  3. Provide adequate methodology to use the VB Environment.

Development issues associated with these objectives include:

  • Integration of a data model for archiving, publishing and lecture description.
  • Design of the distributed lecturing environment.
  • Tagging of lecture content for efficient archiving and retrieval.
  • Definition of VB objects/building blocks.
  • Design of the VB network with embedded the VB tools, managing its various modes (lecture set-up, on-lecture, off-lecture)

The VB system utilises the high bandwidth infrastructure of academic institutions, and implements state-of-the-art techniques and formats in order to facilitate lectures when the tutor and the students do not reside in the same physical space. The resulting tools and methodologies will be used:

  1. In highly specialised courses, when the participants and tutors do not reside in the same institution (i.e., joint courses).
  2. To support distributed lectures when one of the tutors is on the field of research (i.e., in an excavation area.)
  3. When the physical presence of the students is not possible (i.e., specialised medical operations).

 

System requirements and features

Systems that support distributed meetings or distance education force all awareness and communication to be mediated digitally. Users must find ways to compensate for lost information and develop social protocols to replace those disrupted by technology. Synchronous meeting support systems have been a research focus for thirty years (Begeman et al., 1986; Kraemer & King, 1988), and a consistent conclusion is that systems must support diverse interaction channels.

 

Classroom Interactions

In the distance education context, the key focus is the awareness and communication that link instructor and students. In standard classroom instruction, a flexible range of communication channels is available—visual observation, voice, expression, gesture, passing notes, writing on a board, throwing an object for emphasis, walking about to view student work. Managing them isn’t easy: Instructors profit from training, and even after years of experience, effective teaching is a demanding task. Table 1 depicts a variety of common interactions.

 

Interaction

Viewing and hearing the lecturer, including gestures

Monitoring arrival and departure of participants

Slides, with the ability to point or mark for emphasis

3D representations to make the lecture more realistic

Spontaneous writing and drawing (as on blackboard)

Student questions on lecture content, including ability to support another's question (e.g., nodding in class)

Spontaneous questioning of students by instructor

Process-related issues, such as level of comprehension (in a class, communicated publicly with a comment or privately by facial expression)

Discussions among students

Demos or labs

Table 1.Common interactions

 

System functionality

The VB environment revolves around:

  • The presentation layer of the VB environment, which addresses issues of how the overall environment will look, the different set of tools (lecture management tools, lecture organization tools, etc.), and the user interface.
  • Network issues, defining the required and appropriate network infrastructure and standards. The network infrastructure has to address issues related to videostreaming, encoding and decoding of multiple streams, etc.
  • The architecture of the database, which defines the way content will be archived and stored and how information seeking and retrieval will be organized for optimum results.
  • The VB environment modes, providing users with both on-lecture and off-lecture modes with well-defined roles, rights and privileges.
  • The common course and its content, which will serve as a pilot for subsequent lectures. This content must define the types of media to be used, the required material and the optimum way to deliver it.

 

Virtual Blackboard features

A consistent recording of what users need from an interactive distance-lecturing environment, along with research on distance lecturing and e-learning systems pointed to specific functional components of the environment. VB contains components according to the nature of the lecture and content. The environment provides the lecture organizer with an extremely flexible authoring tool to create the overall outlook of the participants’ screen (both lecture’s and students’). This authoring tool consists of multiple windows (web parts) with content (its window will contain a functional component or tool) that can be integrated in a common container window interacting with each other. More analytically these functional components are:

  • Video
  • Audio
  • HTML pages
  • Text
  • Whiteboard
  • Application sharing
  • 3D representations
  • Still images
  • File transfer
  • Email
  • Chat
  • Frequently Asked Questions
  • Participants list
  • Questions & Answers

VB integrates all the above components in a user-friendly interface that can represent different content in a single window.

 

Virtual Blackboard user interface

The main characteristic of VB is the simultaneous implementation and integration of content originating from various sources. One of the critical success factors of VB is the development of a presentation system that is able to manage different content sources and provide users with a flexible and customisable tool to present content uniformly. According to the dashboard philosophy, each web part presents a different kind of lecture material i.e. a web part host the lecturer’s video/audio; a web part will host the shared application among the participants; a web part will host the whiteboard, etc. as shown in Figure 1. Web parts will be interconnected with each other during the lecture and they will maintain these connections for offline use.

The key media is video/audio of the lecturer. The whole lecture and the other web parts will evolve according to the central web part that hosts the video/audio of the lecturer.

The connectivity among web parts remains even after the lecture is stored and archived. The lecture has a unique URL presented in a browser window that contains web parts throughout which the lecture can be used offline. According to this procedure, there will be a set of URL’s for already taught lectures available for reuse.

 

Figure 1.Virtual Blackboard user interface

 

System architecture

The architecture of VB is based in a pure three-tier model consisting of the database layer, the middle layer (Data Integration Mediator) and the presentation layer. Figure 2 presents an overview of the proposed architectural specification with Data Integration Mediator approach. Lecture data are stored in the file system and the relational database. The system stores and manipulates structuring and lecture organizing data, while all the actual media files (images, streams, presentations, documents, html content, etc.) are stored separately in a high-availability file system. The distance learning web application and the authoring applications access the lecture data for update/ retrieval through the Data Integration Mediator. The mediator provides a consolidated view that focuses on the lecture and/or course structure in a way that is independent of the underlying database and or file system.

The implementation of the Data Integration Mediator requires the definition of a specialized mark-up language that will be used for structuring lecture data and organizing electronic courses. eXtended Markup Language (XML)  and e-Course Definition Markup Language (eCDML) (spell out) provide the initial framework for this middle layer.

 

Figure 2. Overall architecture of VB environment

 

The web application (both business logic and presentation layer) is designed to manipulate course and lecture material. The presentation layer is designed around the MPEG-4 concept and specific style sheets for presenting the different groups of users, including support for personalized views. The advantage of adapting an XML approach in presentation is that multiple views (even in different formats: HTML, PDF, WML, etc.) can be achieved without altering the lecture data and by modifying only the presentation layer. This mechanism easily incorporates any future presentation format. Figure 3 presents an overview of web application mediator coupling according to the concept described.

 

Figure 3. The different architectural layers of the environment

 

MPEG-4

MPEG-4 is an ISO/IEC standard developed by MPEG (Moving Picture Experts Group). These standards made interactive video on CD-ROM and Digital Television possible. The basic features of MPEG-4 that concern also the further development of the VB system are:

 

Roles in the Virtual Blackboard environment

The user needs analysis indicated clear roles for the VB environment. The use of synchronous techniques for delivering the lecture simulates the real classroom by allowing participants to keep traditional roles, however the responsibilities and the activities of each of them changes to meet the specific distance lecturing requirements. The user needs analysis and the state-of-the-art analysis verified that there are four different discrete roles in the distance lecture environment, these roles are:

  • Lecture Organizer;
  • Student;
  • Lecture Manager; and
  • Lecturer.

 

Lecture Environment

In VB, the ‘Lecture Environment’ describes the scene and the participants of the lecture as well as the content of the lecture and the tools and infrastructure that are used to deliver content to participants. Professors, students and mediators are persons associated with one or more roles. A mediator is someone who gives lectures under professor’s guidance, or who manages the system inside the lecture scene or manipulates the content. A lecture can be divided into three stages.

The first stage occurs before the lecture. During this stage the lecture is organized, the content source is defined, the web parts are selected or created and the media through which, the content will be accessed or transmitted is specified.

The second stage occurs during the primary instruction or lecture. The lecturer along with mediators and students are engaged in instruction using VB.

The final stage starts when the lecture ends. The major concerns at this stage are archiving and reusing materials.

Roles in the VB environment have specific rights:

  • The lecture organiser creates the web parts needed for the lecture, and is responsible for the type of media as well as for the content and the scenario of the lecture.
  • The lecturer reviews and may change the lecture scenario by the lecture organizers.
  • The lecture manager guarantees the proper and reliable presentation of the lecture in terms of lecture scenario, available technology, and enrolment management. The lecture manager also oversees the presentation environment in stage two.
  • Students interact with the lecture in both stage two and stage three.

 

Conclusions and implications

VB is still a research project that remains to be evaluated within a consortium of partner Universities and commercial organizations. It shows an innovative approach to distance learning by integrating technologies that facilitate different lecturing/learning modes, including synchronous (on-lecture, off-lecture, as well asynchronous (bulleting boards, forums). Furthermore, it integrates MPEG-4 compression for real time video. This technology has yet to realize its full potential. We do not yet know which features and interfaces will be most useful. However, this system provides a variety of communication channels. The challenge is to determine how best to use these channels and their interconnectedness. At present, we have little understanding of appropriate conventions for different interaction classes. More research and development is required.

 

References

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