Subject: Science Education Portals
Date: Sat, 11 Dec 1999 11:10:38 -0500
From: Geoffrey Fox <gcf@npac.syr.edu>

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Reply-to: gcf@npac.syr.edu
To: "Roscoe Giles" <roscoe@bu.edu>, "Reagan Moore" <moore@sdsc.edu>,
    "Ann Redelfs" <redelfs@sdsc.edu>,
    "Scott Lathrop" <scott@ncsa.uiuc.edu>,
    "Raquell Holmes" <rmholmes@bu.edu>, "Ilona Lappo" <lappo@bu.edu>
Subject: Science Education Portals
Date: Sat, 11 Dec 1999 11:10:38 -0500
From: Geoffrey Fox <gcf@boss>

I must admit that I do not understand the significance of the term
"partial ordering" as applied to events.
Let us decde events are units of information (essentially messages) which
have various tags which perhaps always include a time-stamp and also
others such as "sender" "subject" (as in email events), some indicator of
domain (to distinguish mouse, email, voice, user customization events) etc.

Sometimes as in email or MPI messages, events are sent out and stored in
distributed queues associated with particular recipients. Other times
they are "all" stored somewhere (usually in a source dependent queue) and
then "listened to" by recipients who register interest.
Given the large number of events implied by integration of all communication into
queued rather than synchronous delivery, the "architecture of event system"
appears a major issue. I usually note that "collaborative systems" essentially
federate otherwise disjoint event services. (e,g. they transfer mouse events
from one machine to another)

There are some quite interesting implications I think of using events to
do audio video conferencing. Current approaches involve 3 distinct buffer (aka event) sizes
1) Real-time audio/video conferencing (CUseeMe, Tango, Access Grid) fraction of a second
2) Real Audio (several seconds)
3) Download file locally and play (indefinitely large)
Thinking of AV as events (with very fast real time processing if necessary) of a small size
which can be concantenated for modes 2) and 3) (and transmitted redundantly for mode 1))
appears to me to allow more flexible robust A/V conferencing where you can dynamically
move between 1) 2) or 3) dependent on line-quality and lateness of arrival of listener
to a session. This is perhaps a special case of integration of synchronous and asynchronous
collaboration enabled by an event based approach. It also emphasize that a difficult issue
(computer science research) is retaining real-time (high) performance for synchronous modes
even with intermediate buffers and filters (for user customization such as that needed
for universal access)
A simple but important issue is "event format" (e.g. XML DTD for events) which
allows very fast retieval of critical tags and allows a more relaxed analysis
to fully process (in a message lingo, we need certain tags in mesage header)

The event model is (in my opinion) the most natural ("best") for all portals.
We should define differences between education and other (research, commodity) portals.
Identification and support of "learning specific functions" appears important.
Perhaps Assesment is a good example of a critical learning area which is not
so critical in other portals (although in commerce portals, merchants would data-mine
your navigation through the portal to both evaluate portal and decide how best
to market to you)
We are currently emphasizing collaboration more than say the current discussion
of "computer portals" does. Is this a difference?

Geoffrey Fox  gcf@npac.syr.edu,   http://www.npac.syr.edu
Director of NPAC and Professor of Physics and Computer Science
Phones Cell 3152546387  Office 3154432163 Npac 3154431723 Fax 3154434741

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