Collaboration Collaboration is the aspect of the virtual K-12 school or university which is most sensitive to teacher-pupil separation. Distance education implies a distribution of students, an obvious obstacle to learning. However, Web technologies also allow school children to interact with their peers internationally. Distance education holds the promise of individualized learning on the users timeframe, but two-way communication between student and teacher must be supported. Collaboration between the learner and leading experts is technically possible through a hierarchical structure linking learners and a mix of distance university and leading expert partnerships. Learning remains a group activity even if conducted electronically, therefore multi-user collaboratory tools are needed to support group navigation, sharing of group experiences, and group authoring of content.
Collaboration is a particularly demanding distance education application because it cannot use caching and a hierarchical server structure, approaches which serve information access and delivery applications so well. Collaboration is sensitive to available bandwidth and requires the best compression and transport technology. As discussed above, a hybrid scheme involving a mix of locally cached (CD-ROM) material with high value interactive access at a distance is quite promising. Our Java collaboratory Tango supports this model, and we hope to perform a set of experiments with it soon.
Our project experience with videoconferencing suggests that 56 kilobaud is the lowest practical speed, ISDN (128 kbaud) is adequate, but full screen video at 30 frames per second requires the standard 1.5 megabits/sec bandwidth with MPEG1 compression. We are experimenting with the use of audio (which is practical at 28.8 kilobaud) as a form of annotation to enhance on-line course material. This can be supplemented by images or new video codecs such as Java H263 applets on low speed lines.
Authoring As discussed in Section 2.3, the ubiquity of the Web suggests that we will soon see Web operating systems replacing proprietary operating systems, and the growth of a Webtop (rather than proprietary desktop) personal productivity environment. Content authoring in a Web environment will become a central function in distance education.
Homework will be done in an electronic environment as part of the learning experience. Web-based content must therefore be interactive, and editable. Students must be ably to create, modify, and edit on-line hypermedia material as part of the learning process. As part of our computer science classes we have developed a virtual programming laboratory where students can develop, compile, and run (homework) problems [Dincer:97a], [Dincer:97b].
Active simulation Simulation support is needed to provide two-way interactivity that enables real-time interaction with a simulated world. Students must be able to interact with active simulations by guiding the process (e.g., setting parameters, triggering events), navigating regions of interest, and accessing explanatory annotations (written either by teachers, application experts, or other students).
Virtual reality could be a revolutionary technology to improve the learning environment by immersing student in physical or more abstract information spaces.
Navigation The Web is an excellent source of educational content (see Kids Web [Kids:95a], and ThinkQuest [Thinkquest:96a]) but the growing volume and complexity makes it too easy for students to get lost in cyberspace. Disciplined navigational tools are need, perhaps incorporating multi-sensory feedback [19] to create a coherent integration model of various multimedia modalities (hypertext, sound, video, simulations).
Structured navigation and free exploration must be balanced to allow the teacher to efficiently guide the investigation and the student to employ his or her own optimal model of learning. We have experimented in existing NPAC projects with unstructured exploration (e.g., KidsWeb, and a video archive) and structured courses and tutorials (e.g., on-line computational science courses [CPS:96a], [Ed:96a], [Fox:95n]).
Assessing the impact of new technologies and approaches on learning is itself an application where Web technologies are useful. Tools are needed to track students navigation pathways and their reactions to selected sequences, then we must use this information for evaluation and individual-student course refinement. It is straightforward to log the URLs of the pages accessed by teachers and students. We are using this today to link recorded audio of lectures to particular pages being discussed. Tango supports complete logging of a multimedia collaborative session. Related research on navigational patterns termed cognitive throughput by disabled learners is designed to anticipate the response of users in an information environment. Tracking navigational pathways and inter-target intervals allows us to anticipate future navigational direction (to pre-download content and improve performance), and support cognitive studies of user needs for improved information design [Sherman:97a].
The Unit of Information In traditional models, we teach and learn using lectures supported by books, notes, and presentations in the form of bulleted items and summary lists in a linear sequence. In the Web-based environment we envision, where a distributed hierarchy of information-on-demand servers are available, and students interactively explore active simulations, we must consider what is an appropriate unit of information.
The hyperlinked environment of the Web makes ``sequential'' books unnatural--people are better than computers at flipping sequentially through electronic pages. This may suggest an electronic encyclopedia model as the optimal model for the Web. This model would likely contain short, linked, modular entries produced by multiple authors having several different levels of description for a given subject.
The natural size of an information nugget is roughly a computer screenful. It is interesting to note that this is similar to the amount of data displayed on a viewgraph on an overhead projector. Thus we can expect presentation technology and techniques to be an important source of ideas for Web education.