SemanticClipboard
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<html xmlns="http://www.w3.org/1999/xhtml">
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<title>
The Semantic Web Clipboard - Design Issues
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<address>
Tim Berners-Lee<br />
Date: 2004/01, last change: $Date: 2004/01/15 19:47:08
$<br />
Status: personal view only. Editing status: first draft.
</address>
<p>
<a href="./">Up to Design Issues</a>
</p>
<hr />
<h1>
Semantic Clipboard
</h1>
<p>
One way of looking at the Semantic Web is a breaking down of
barriers between applications. An example I have often quoted
is that I would like to be able to drag a photo album onto a
calenar application and see the photos on my calendar.
</p>
<p>
What would this actually take?
</p>
<p>
The intersting case that the calendar application and the
phto album application were written indepedently, without
this case in mind. Suppose they were, though written to be
semantic-web aware. So they will have ontologies for the
things they deal with (photos, events resepctively in this
case.) They will store their data, or at least a copy of it,
in RDF.
</p>
<p>
The clipboard, which stores things which we copy and paste,
is a complex thing. It doesn't always hold the value of
something clipped, it sometimes just remembers where it was
clipped from. There is a form of negotiation between the
source and destination about the format for the data to be
transferred. This is why you can copy from text from a web
page (which is structured hypertext) into a plain text
message. There is a negotiation, and the source and
destinatio can both use a plain text clipboad type.
</p>
<p>
In this example, we can imagine there being a Semantic Web
clipboard type. The data is basically transferred as an RDF
graph. But that isn't the end of it. Different applications
understand different vocabularies (ontologies). So a semantic
web clipboard (or the application) does more than just
transfer data. It arranges to convert it into a useful form.
</p>
<p>
When you drag something onto the calendar application, it may
be expecting events. It may be able to use anything which has
at least a start datetime and and a description. the typical
vocabulary here is iCalendar-like, such as @@@@. The photo
has a date of creation and may have a form of description. It
will typically have technical details of the exposure. The
typical vocabulary here is EXIF-like, such as @@@@.
</p>
<p>
RDF Interest group people have looked at conversion tools. At
MIT we've had fun converting things like this deliberately.
How can it happen in this example?
</p>
<p>
Somehow, the user must authorize conversion rules to be
available to the semantic web clipboard, so that the
convertion can be done. The clipboard indexes the rules,
knows what form of information is needed by the application
through some kind of registration, and knows what sort of
information is available on the clipboard.
</p>
<p>
Typically, these things are customized. I might like the
description of the event of a phtograph being taken to have a
list of the people in the shot, if it is known; others might
just want the brief "Pic!".
</p>
<h2>
Sources and organization of rules
</h2>
<p>
An advanced user who uses some kind of tool to generate a
rule, as users do today for email filtering. The user is a
third party. Third party rule sources may include system
administrators.
</p>
<p>
The source could be the creator of one or other program:
calendar or photo album. One might exect the program which is
released second to come with rules for connection to other
things already released. In this case, there is some order in
that the rules link applictions in a directed way. If in
laterreleases both applications offer rules to convert the
same way, then a choice has to be made, just as one sometiems
has to chose whether to trust the provider of the printer or
the provider of the operating system when installing a
printer driver.
</p>
<p>
Users will have to track the trust worthiness of many
different sources of data, but these rules will give a lot
back for something quite small.
</p>
<p>
There is a form of entropy which increases as these rules are
used. Some rules may be reversable, but typically they are
not. You can't turn every event back into a picture, and you
can't event turn a picture taking event back into the picture
as you have lost some data. An event is in this example a
more generic thing than a picture. One might assume that the
system will in general try to reduce this information loss.
This will involve trading at the highest level, or usingthe
fewest rules. The sense of specificity might therefore form
an organizing technique. This is similar to a form of pecking
order between a rich text clipboard and a plain text
clipboard: is applications can use the more sophisticated,
less information is lost.
</p>
<h2>
Conclusion
</h2>
<p>
The Semantic Web clipboard might be a nifty hack in the short
term, might be a mainstay of desktop interoperability in the
future. From the reseacrh point of view, the rule management
involved is a miniature version of the Semantic Web rule
indexing search engine.
</p>
<hr />
<p>
<a href="Overview.html">Up to Design Issues</a>
</p>
<p>
<a href="../People/Berners-Lee">Tim BL</a>
</p>
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