Interactive Distance Learning
over Intranets
K URT M ALY, H USSEIN A BDEL-W AHAB, C. M ICHAEL O VERSTREET, J.
C HRISTIAN W ILD, A JAY G UPTA, A LAA Y OUSSEF, E MILIA S TOICA, AN
D
E HAB S. A L-S HAER
Old Dominion University Many distance learning systems claim to be
interactive, but few can offer two-way video,
on-the-fly interaction, and application
sharing. The authors describe the Interactive
Remote Instruction system, which links sites
over a high-speed intranet.
Distance learning — education without a  central classroom — has helped busy people obtain college credits or complete training they might otherwise not have done. Methods of distance learning range from simple correspondence courses and broadcast TV with reverse audio to specialized video conferencing tools, such as Proshare or Flashback, and Web-based courses.
The current version of Old Dominion University’s Teletechnet system, for example, uses broadcast satellite technology with terrestrial audio feedback from students and e-mail to connect the main campus in Norfolk, Virginia, to up to 23community colleges throughout the state, as well as selected industrial and government sites. More than 3,000 students are enrolled in Teletechnet.
However, limitations in the technologies supporting Teletechnet and similar systems become critically apparent as the demand for them continues to rise. To address these limitations, our research group built the Interactive Remote Instruction system, which allows students at
geographically dispersed satellite campuses and community colleges to take a class “together.”Access from home PCs through a Windows NT port is planned but not yet available.
IRI improves on Teletechnet technology in four areas:
♦Video resolution. The limited resolution of Teletechnet’s TV images restricts the quality of information that can be presented. IRI offers images with a resolution of 1152 x 900 pixels.
♦Asymmetrical video presence. Instructors cannot view the students at remote Teletechnet sites nor can students see students at other sites when they speak. With IRI, each course participant’s (student’s and instructor’s) workstation is a window to a virtual classroom. All class participants see the speakers on their screens, so everyone has the same experience.
♦Interaction. Teletechnet students have limited opportunities to interact both in and out of class. In class, IRI helps each student prepare for assignments and take notes and aids collaboration in group projects.
♦Instructor support. TV-based classes typically have technicians and camera people managing the connection but little user support is provided. IRI helps instructors prepare a lesson plan off-line, which they can then use to guide class presentations. The class management  helps orchestrate and manage an interactive classroom. , The instructor can selectively call on students or check the status of their workstations.
♦Computer simulations. TV-based systems provide no way to do a hands-on computer simulation of, s
ay, a chemical experiment. With IRI, students can ask questions or demonstrate proficiency by directly manipulating such a simulation.
In this article we describe IRI and the lessons learned deploying it. We first deployed IRI to teach a fall 1995 graduate course in software metrics. We then evaluated it in terms of logistics, reliability, performance, and usability, performing off-line experiments to try out new features and to develop protocols that would improve IRI use. We subsequently reengineered IRI into an open architecture with a published specification as version 1.0, which became available just recently
(www.cs.odu.edu/ tele/iri). We used version 1.0 to teach a junior-level software engineering course in the fall 1996 semester.
INTERACTIVITY CHALLENGE
The days of the “talking head” approach to video instruction are ending. Digital technologies that support interactive, multimedia virtual classrooms are delivering education much more efficiently and effectively to students in range of situations. Any student who can has links to an intranet can participate in this type of education.
The main problem with the talking head technology is that it did little more than present information that students might easily digest on their own. Only when students put information into a different or larger context, such as interaction in a classroom situation, do they fully develop their creativity and critical thinking skills.  In fact, students using TV-based systems complain about the lack of interaction with a faculty mentor, often dropping out because of their frustration at not being able to get rapid feedback to questions. Faculty also cite lack of interaction as the top drawback to televised instruction.1
Thus, interactivity is a primary goal of distance learning systems—but it also poses challenges. An energetic instructor might use slides, overheads, paper handouts, photographs, graphics, video, and audio — each of which requires separate tools to deliver. Distance learning systems must make these resources available at each workstation and at the instructor's fingertips, allowing instructors to tailor course content dynamically to the students' needs and learning styles and to select appropriate intervention strategies on the basis of what the system reveals as it monitors students' interactions.
For TV-based systems such interactivity is both complicated and costly. Custom hardware and software are required before students at one site can see students at another. TV-based systems with two-way video require either a high-bandwidth multicast network or if satellite transmission is used, upl
ink stations at each receiver site. In contrast, computer-based systems can send compressed audio, video, and data streams, as well as two-way video, with microphones and speakers supporting the audio connection—all relatively simply and inexpensively.
VIRTUAL CLASSROOM
Our work in IRI has concentrated on providing a virtual classroom for geographically dispersed students to share a traditional environment. To guarantee a certain level of performance, IRI is implemented on an intranet, a network in which access is controlled so as to guarantee system performance.
Before class
The virtual classroom environment supports a variety of roles and session types. The user invokes IRI from a startup screen, as shown in Figure 1, which allows him  to define a role and a session type. Supported roles are
♦Instructor. The person in charge of a class, normally the person who teaches, handles grading, and manages a class during lecture time. The  instructor controls the class-management policy (the
freedom of individual students to influence the class, the functions and resources available to students, and so on).
♦Student. Anyone registered to take the class.
♦ A dministrator. The person who configures the hardware, registers students, and so on.
Teacher, student, and administrator are static roles (persisting throughout the class). There are also two possible dynamic roles—presenter and tool controller—which may change during class.
The presenter is typically the  instructor  but can be any class member. At a specific time, the presenter uses one or more tools, some possibly  running in collaborative mode, to lead a discussion or present information to the class. By “collaborative,” we mean that all students in the class can see the output. The tool controller is any person who controls the application the presenter has selected. This collaborative approach is important because it allows everyone in the class to see the same tool actions and results simultaneously.
The startup screen asks the user to specify the session type and in most cases the date the class will be given. Session types include
♦Lecture. Lecture sessions can be class or class with recording. Selecting “class” starts an interactive virtual classroom on the set of workstations defined by the administrator for that class. Selecting “class with recording” records the class session for later viewing.
♦Review. In this session type, students who miss a class or wish to review class material can replay the class session, which IRI had automatically recorded in the “class with recording” mode.
session下载♦Lesson planning. In this session type, a presenter identifies resources or tools (such as application software or files) that will be used in an upcoming class session. This simplifies class start-up time and because needed resources are known beforehand lets software and files be available at each site.
♦Resource addition. In this session type, the user ( instructor or student) identifies resources needed for a class, such as homework, quizzes, surveys, grades, assignments, projects, programs, and syllabi. IRI copies this information from the user’s files into the appropriate folders maintained for the course material. The folders become part of WebBook, an IRI resource available to students with Internet access from any location (home, for example) and a browser like Netscape 2.0 or higher. Thus, students can access class material outside of scheduled class times  through the intranet.  WebBook contains  instructor’s notes and handouts, as well as the notes the student has taken during class. It also contains information about the student taking the class.
Returning to Figure 1, the  instructor has activated a resource addition session to add previously prepared Powerpoint slides  . The presentation list identifies resources which have been identified as part of this session  which we explain in more detail later.
During class
Figure 2 shows the computer screen during class mode. (The images in this figure were taken with older video cards. We plan to use cards with better resolution in the future as less expensive cards become available.  The large video screen is an NTSC quality image with a high frame rate, which originates at a presenter’s workstation.  If the presenter’s workstation is equipped with alternative video sources, the presenter can switch the source for this image to any NTSC video so that VCRs, TVs, and laptops can be used for presentations. Typically only the  instructor’s workstation would be equipped with an NTSC video switch.
Group discussion
Figure 2 also illustrates IRI's support of group discussions. On the right side are video images of students participating in a discussion. Students can elect to join the discussion by selecting one of the video images, or the  instructor can call on them by selecting the Call Student function (bottom function
bar), which displays the class roll, and choosing their names. IRI can display up to four videos on all workstations: the presenter’s, up to two students’, and a site image the  instructor selects (“ODU” bottom right). At start-up, the  instructor is in the presenter’s window (large video image) and no students are on-screen.
Audio is hands-free (no buttons must be pressed to initiate or discontinue a conversation), although students can turn off audio.
In the center of the screen in Figure 2 is a list of class participants, their locations, and the status of their workstations  in the virtual classroom. This allows the  instructor to call on individual students and tells the presenter that individual workstations are functioning and thus that students are still part of the class. Workstation status is also useful information in troubleshooting network problems, since the  instructor  can sometimes rectify a problem by restarting the session.
Tool sharing
The IRI environment provides for three types of tools. (We describe the IRI tools in more detail later.)
♦Common X Windows. These include tools such as Netscape, acroread, Matlab, gdb debugger, and xterm, which were not written to be shared.
♦IRI multiuser. These tools were written to exploit the shared networking environment of the IRI architecture.
♦IRI single-user. These tools run only on one user’s workstation.
The first two classes are shared tools. When a shared tool is in use, the presenter’s video image shifts to a smaller window in the top right corner (maly), as shown in Figure 3. In this figure, Netscape (top window) and the IRI slide tool (bottom window) share the main work-area. Along the top left side of the screen is the lesson plan, which lists the tools the presenter  will use this class and notes on the objectives of the lesson (taken from the lesson planning session, as described earlier). The presenter can invoke tools as needed from a menu or IRI can preload them before the class session (on the basis of input from the lesson planning session.)
Because IRI incorporates XTV, an X Windows tool-sharing engine,2,3 any student can operate any tool the  instructor uses. A student can take control of the tool by selecting “Tool” (second token from the left along the top shared-resource bar in Figure 3). IRI displays the name of the tool controller on all workstations (“maly” to the bottom right of the token). It then broadcasts all changes to that tool’s state to all other workstations.
Shared functions vs. private views and functions
IRI users must understand the difference between what is being shared and what is private. All public resources are identified in a resource bar along the top of the work area. The private functions, which the workstation user controls, are at the bottom of the screen. In addition, IRI identifies the controller of each shared resource for everyone to see. It also keeps a registry of all shared windows with their position and size on the presenter’s screen. The presenter can use a synchronization button to force everyone’s screen to coincide with her own or let a student synchronize his screen to the generic shared image.
Teleawareness
Users should know the consequences of an operation, particularly if it affects everyone on the intranet. Suppose the presenter wants to launch Netscape, which may take up to a minute to appear on everybody’s screen. IRI alerts her to that overhead and asks for confirmation that the operation should continue. It also periodically estimates the time to launch common tools and uses the results to predict the cost. Thus, every time a new tool is launched or a slide is changed in the slide tool, a slide bar indicating the percentage of viewer screens in sync with this action is shown.

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