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    ELECTRONIC NEWSLETTER ON  REASONING ABOUT ACTIONS AND CHANGE        
Issue 98001             Editor: Erik Sandewall             5.1.1998
Back issues available at http://www.ida.liu.se/ext/etai/actions/njl/
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                *********  NEW STRUCTURES  *********

The present Newsletter issue is entirely dedicated to a description
of the new facilities that have been implemented during the last 
month, and which are now operational in their main parts.


FORMULAS IN HTML

One change concerns the representation of formulas in the on-line
text and, in particular, in HTML. This is important for a wider use
of an interactive, on-line communication service in a scientific
domain such as ours. There seems to be two problems: graphics and
ease of reading. The graphics problem is that present versions of
HTML do not provide good support for mathematical characters or 
for the precise layout that is needed in order to make formulas look
good. While waiting for implementations of the recently announced HTML4.0
standard (which will at least provide the character sets), we have
implemented an ad hoc solution within current HTML that is somewhat
reasonable.

As for ease of reading, it is generally recognized that it is more 
tiring to read the same mathematical text on a screen than on paper. 
However, we have now made an interesting observation: the use of color
in the on-line medium may compensate for the disadvantages that it
otherwise has. Basically, the trick is to use several colors that
are distinct but not *too* distinct, such as black and two nuances of
blue, in order to make the text easier to read. The main text is in
black, formulas in blue, and what would be different fonts on paper
is instead different kinds of blue on the screen. This serves a dual
purpose: it adds liveliness to the textual surface, and it also helps
to remedy the character-set problem. Additional colors and hues are
used in the context of citations.

We have developed some simple software that is able to generate both
latex and this kind of formula HTML from a single underlying 
representation, and the body of Newsletter contributions during the
past few months are being converted to this representation. This job
has been finished for the review discussions about received articles;
please take a look at them. The conversion of the article summaries
will follow, and then the panel-debate contributions during 1997.
Forthcoming contributions will be put into this format as they arrive.


ON-LINE CITATIONS

A second change concerns the representation of citations and other
cross-links between discussion contributions, and from discussion
contributions to previously published articles. An earlier implementation
of an on-line "footnote" system (where footnote contents are shown in a
small pane of the browser display, using HTML frames) has now been
connected to the ACRES bibliographic database. The bottom line is that
the author of a contribution can now indicate citations using a global
coding scheme, such as

    c-ecai-94-401

for the paper beginning on page 401 of the ECAI 1994 proceedings,
and the rest will happen automatically: The article code appears 
clickable in the on-line text, clicking it will cause the bibliographic
entry to appear in the footnote windowpane, and from there one can
again click to see the author's homepage or the full text of the paper,
to the extent that these are known to the database.

There is of course also a facility for defining footnotes that are local 
to a contribution, for example for articles that appeared outside the
A I literature and which are therefore not listed in ACRES. The noframe
version of the system presents citations at the end of the contribution,
since on-line footnotes are not available.

These facilities have also so far been realized for the article review 
discussions, and will follow for the other materials.

Authors of contributions during 1997 are kindly asked to check that
nothing has been disrupted in their contributions as a result of this
editing process. At the same time, please check also the wording in
the copyright statement which has been slightly modified in order to
specify this possibility of posterior editing. (The copyright of all
contributions stay with the author).


CROSS-LINKING FRAME PRESENTATION

The discussions during the past months contained several examples of
where an author referred to earlier discussion, not only for a direct
answer or retort to what was said before, but also for a more general
reference. This suggests the need for hot (clickable) links within and
between the discussions. Such hot links may be particularly useful
in HTML frame-based contexts, but some technical problems had to be
solved first. In particular, it must be possible to change the contents
of several windowpanes at a single click, but without redrawing the
whole window. This in turn means that different kinds of discussions
must have equal or compatible window layouts. The existing information
structure has now been reorganized accordingly, and discussion crosslinks
are operational.


IMPROVED SUPPORT FOR RETROSPECTION

The News Journal on Reasoning about Actions and Change appears at the
end of each month, and contains the contributions that have arrived
and have been exchanged by mail during that month. It serves several
purposes:

-  For the reader who has not followed the day-to-day communication in the
   Newsletters, it provides an aggregated way of finding out what has
   occurred.

-  Since the postscript version of the News Journal has a journal-like
   appearance, it may serve as a carrier for research notes and in order
   to give them published status. Research articles are published by
   First publication archives prior to review discussion, but it would not
   be practical to make a separate publication out of each research note.
   The published News Journal issue at the end of the month provides a
   way of grouping several research notes into one periodical publication.

Our original idea was that the News Journal would contain essentially
all the month's contributions, and that the first purpose would be served
both by the HTML edition (on line readable, containing hot links) and the
postscript version (convenient to read off-line on paper). However, due
to the considerable volume of contributions, it may be somewhat difficult
to orient oneself in the HTML version of the News Journal. 

In fact, the contributions to the discussions (both article discussions 
and panel debates) account for the major parts of the volume. This information
is anyway also entered into separate, diachronic structures where each 
discussion is represented as one trace from start to end. Therefore, in
order to facilitate overview, there is now a minimal variant of the
News Journal called the *Digest* which only lists the headings that have
been active during the past month, that is, what articles have been
received, what articles have been discussed, what panel discussions have
been active, etc. Some simple measures of activity are also given,
such as the number of contributions. In addition, of course, the Digest
contains hot links into the respective discussion tracks. The hope is that
for on-line use, the Digest will be a convenient point of entry.

For off-line reading, the postscript version is presumably the most
convenient to use, but it also takes some time to prepare it. The
HTML version of the full News Journal is available instantly, and can
of course also be printed out and read off-line.


PUBLICATION VEHICLE FOR RESEARCH NOTES

Besides providing easy overview, the News Journals have a second purpose
namely to serve as a publication vehicle for (research) notes. To this
end, the Electronic News Journal on Reasoning about Actions and Change
(ENRAC) is being formally registered as a periodic publication with
monthly appearance. The contributions during 1997 will appear retroactively
as Volume 1; 1998 will be Volume 2. More information about this will follow 
when the formalities have been completed.


A NOTE ON METHODOLOGY

The method that is being used here is to develop this new information
service gradually and based on feedback from the application: we "feel
our way" to a design that will fit the users' needs as well as possible.
In fact, it may be understood as an example of action research: new
results are developed concurrently with their use in a selected 
application, although of course here we do it for the results, and the
research is not an end in itself. Anyway, this methodology has its 
pros and cons, for example that all facilities are not ready at once, 
but then when it's ready it should be good. 


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