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<h1 id="title" class="title">SWAD-Europe Deliverable 3.7: Developer
Workshop Report 2 - Semantic Web calendaring</h1>

<div class="reportinfo">
<dl>
<dt>Project name:</dt>

<dd>Semantic Web Advanced Development for Europe (SWAD-Europe)</dd>

<dt>Project Number:</dt>

<dd>IST-2001-34732</dd>

<dt>Workpackage name:</dt>

<dd>3 Dissemination and Implementation</dd>

<dt>Workpackage description:</dt>

<dd><a
href="../../plan/workpackages/live/esw-wp-3.html">http://www.w3.org/2001/sw/Europe/plan/workpackages/live/esw-wp-3</a></dd>

<dt>Deliverable title:</dt>

<dd>3.7 Developer Workshop Report 2</dd>

<dt>URI:</dt>

<dd><a
href="http://www.w3.org/2001/sw/Europe/reports/dev_workshop_report_2/">
http://www.w3.org/2001/sw/Europe/reports/dev_workshop_report_2/</a></dd>

<dt>Author:</dt>

<dd>Libby Miller</dd>

<dt>Abstract:</dt>

<dd>This report summarises the second SWAD-Europe developer
workshop, held in Bristol on 9 October 2002 (<a
href="../../events/200210-cal/Overview.html">webpage</a>, <a
href="http://lists.w3.org/Archives/Public/www-rdf-calendar/2002Aug/0003.html">
announcement</a>).</dd>

<dt>STATUS:</dt>

<dd>First version published 2002-10-24. This version 2002-12-12:
report complete.</dd>
</dl>
</div>

<h2>Contents</h2>

<hr />
<ol>
<li><a href="#summary">Summary</a></li>

<li><a href="#outcomes">Outcomes</a></li>

<li><a href="#usecases">Usecases</a></li>

<li><a href="#faqs">FAQs and answers</a></li>

<li><a href="#attendees">Attendees</a></li>
</ol>

<p><a href="#tools">Appendix A. Projects and Tools</a></p>

<hr />
<h2><a id="summary" name="summary">Summary</a></h2>

<p>The recent work going on in the <a
href="http://www.mozilla.org/projects/calendar/">Mozilla calendar
project</a> and the <a href="http://www.apple.com/ical/">iCal Apple
application</a> has stimulated interest in the subject of creating,
displaying and exchanging calendars. These products make it simple
for users to create and make available calendars represented in the
<a href="http://www.ietf.org/rfc/rfc2445.txt">iCalendar standard
(RFC 2445)</a>, and to subscribe to the calendars they are
interested in which have been created by other people.</p>

<p>Since early 2001, the <a
href="http://www.w3.org/RDF/Interest/">RDF interest group</a> has
had an informal <a
href="http://ilrt.org/discovery/2001/04/calendar/">taskforce
examining calendaring and scheduling issues and RDF</a>. This arose
out of an <a href="http://www.w3.org/2000/01/foo">initial exercise
by Tim Berners-Lee</a> which described how one might approach the
problem of converting iCalendar to RDF, and later, from discussions
at the <a
href="http://www.w3.org/2001/02/allgroupoverview.html">W3C
Technical plenary 2001</a>.</p>

<p>Calendaring is an interesting application of RDF because it is
such an important part of people's day-to-day lives, and because it
also encompasses difficult philosophical and modeling problems,
and social, trust and privacy questions. It straddles all levels of
the Semantic Web from simple queries to find out who is at a
conference, to complex scheduling problems involving logic.</p>

<p>There have been several attempts to model calendaring formats in
RDF, including the <a
href="http://www.ilrt.bris.ac.uk/discovery/2001/06/schemas/ical-full/hybrid.rdf">
'hybrid' model</a> (Michael Arick and Libby Miller) <a
href="http://www.w3.org/2000/10/swap/pim/ical.rdf">another
iCalendar model</a> (Dan Connolly), and a <a
href="http://www.w3.org/2000/08/palm56/datebook">Palm model</a>
(Dan Connolly). ICalendar is the standard format used by most
devices and software for calendaring and scheduling, but is also
highly complex and difficult to implement in its entirety.</p>

<h4>Workshop aims</h4>

<ul>
<li>Firstly and principally to present arguments and usecases why
an RDF version of the standard would be <i>more useful</i> than the
iCalendar format (which is presented in a text based format called
<a href="http://www.ietf.org/rfc/rfc2425.txt">'mime-directory' (RFC
2425)</a>). Many usecases were presented, all focusing on the need
to combine event-based information with other sorts of information
- for example about people, documents, places. These usecases are
summarised <a href="#usecases">below</a>.</li>

<li>A second aim was to consider how we might decide on a single
format for RDF calendaring information. An interesting proposal was
put forward by Dan Connolly: to take the RDF calendar vocabularies
people were actually using and use them to create a schema. This
outcome and others are detailed <a href="#outcomes">below</a>.</li>

<li>Thirdly, the workshop aimed to bring together developers, and
enable them to demonstrate applications that they had been using or
creating. Software presentations included demonstrations of Apple's
iCal, Mozilla Calendar, Retsina Calendar Agent, and demonstrations
of calendar tools in Javascript, Perl, Python and Java. Details are
described in the <a href="#tools">tools appendix</a>.</li>
</ul>

<p>Additionally, there were two background presentations, on
iCalendar and the Calsch working group (Greg FitzPatrick) and a
survey of Knowledge Representation formalizations of time (Pat
Hayes).</p>

<p>Notes made at the time of the workshop are available <a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-09.html">from
the RDF Interest group chat channel logs</a>; annotations of
demonstrations and usecases are available from <a
href="http://rdfig.xmlhack.com/2002/10/09/2002-10-09.html">the RDF
Interest group blog</a>.</p>

<p>There were twenty-one participants of the workshop, from the
industrial, Open Source and research communities, and including
representatives from the RSS community, the XML/Topic Maps
community, iCalendar IETF working group, W3C, Universities of
Southampton, West Florida, Madrid and Bristol; also companies:
Mediatrans, HP Labs, Techquila, BBN Technologies / Verizon, SkiCal
consortium; and from various countries: Italy, Spain, US, Belgium,
Sweden, and UK.</p>

<h2><a id="outcomes" name="outcomes">Outcomes</a></h2>

<h3>RDF calendar workspace</h3>

<p>
As a result of the workshop an <a href="http://www.w3.org/2002/12/cal/">RDF calendar workspace</a> has
been created, containing  a testcase-driven schema, testcases, details of meetings held, and notes
on applications. 13 virtual meetings have been held:  These meetings have been attended by open source
developers; industry, academic/research and content and tool producers: Mozilla calendar and Apple
developers; members of the RSS community; Chandler developer; members of
the W3C team; iCalendar
(RFC 2445) specification contributors; and SWAD-Europe project members.
</p>

<h3>Ideas for the future of iCalendar in RDF</h3>

<p>See also posts to <a
href="http://lists.w3.org/Archives/Public/www-rdf-calendar/">www-rdf-calendar@w3.org</a>
for recent discussions on email and irc.</p>

<p>NB References are mostly to <a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-09.html">logs</a>
written by scribes who were at the meeting. There were no formal
procedures for actions from the meeting.</p>

<ul>
<li>create a W3C namespace for a schema, <a
href="http://www.w3.org/2002/12/cal">http://www.w3.org/2002/12/cal</a>
(http://www.w3.org/2002/10/calendar has been taken) [<a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-09.html#T15-28-24">
ref</a>]</li>

<li>put there: <a
href="http://www.w3.org/2000/10/swap/pim/ical.rdf">Dan Connolly's
RDF schema for iCalendar</a> which is mechanically derived from
iCalendar data. <a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-09.html#T15-32-25">
[ref]</a></li>

<li>The so-called <a
href="http://www.ilrt.bris.ac.uk/discovery/2001/06/schemas/ical-full/hybrid.rdf">
'hybrid' schema</a> will be credited but not used directly; this is
because the hybrid schema makes a number of judgement calls to make
clear the model behind the iCalendar mime-directory <a
href="http://www.ietf.org/rfc/rfc2445.txt">RFC 2445</a>. [<a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-22.html#T16-30-56">
ref</a>]. This means that it's difficult to automate the conversion
between iCalendar and RDF, which seems to be essential in the
current circumstances. It's likely that the new schema will be
similar in many respects to the 'hybrid' schema, although it's not
clear how to compare them.</li>

<li>Dan Connolly proposed a mechanism for changes in the new
schema: "we announce all changes to www-rdf-calendar. If anyone
screams, within 7 days, we'll back out the changes (for further
discussion) and status says 'If the CVS date below haven't changed
in the last two months, active developments have likely ceased' "
[<a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-09.html#T15-30-13">
ref</a>]</li>

<li>example data will be got from various sources e.g Terry Payne's
Retsina agent [<a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-09.html#T15-32-49">
ref</a>]</li>

<li>Dan Connolly is also willing to keep an index of consumers of
the data [<a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-09.html#T15-33-10">
ref</a>]</li>

<li>Libby Miller would like to see what subsets of the schema are
used by what different tools, and lots of example data [<a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-09.html#T15-35-26">
ref</a>]</li>

<li>How tos: 'something that generates iCal files for mac and moz
fans' [Dan Brickley, <a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-21.html#T16-54-44">
ref</a>]'; 'how to use the schema in a few known and useful ways'
[Dan Connolly, <a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-21.html#T16-59-18">
ref</a>]</li>

<li>Writing dates in an XML-friendly way. The group appeared to
agree that writing dates with hyphens - as per <a
href="http://www.w3.org/TR/xmlschema-2/#dateTime">XML Schema
datatypes</a>, <a
href="http://www.rfc-editor.org/rfc/rfc3339.txt">Date and Time on
the Internet: Timestamps RFC 3339</a> and <a
href="http://www.w3.org/TR/NOTE-datetime">W3C's note on Date and
Time Formats</a> was preferred to no hyphens, as in <a
href="http://www.ietf.org/rfc/rfc2445.txt">iCalendar RFC 2445</a>.
[<a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-09.html#T14-58-38">
ref</a>].</li>
</ul>

<h2><a id="usecases" name="usecases">Usecases</a> - see <a
href="http://rdfig.xmlhack.com/2002/10/09/2002-10-09.html">Chump</a>
and <a
href="http://ilrt.org/discovery/chatlogs/rdfig/2002-10-09.html">logs</a>
for additional detail</h2>

<h3>J&eacute;r&ocirc;me Euzenat's usecase: Personal information
management and the semantic web</h3>

<p>J&eacute;r&ocirc;me could not attend the workshop, but sent <a
href="../../200210/calendar/SyncLink.html">a usecase</a>. Here's an
excerpt:</p>

<p>Personal information (i.e., Agendas, Address books,
Bibliographies, etc.) has several advantages with regards to the
semantic web:</p>

<ul>
<li>it can be found in great quantities over the web;</li>

<li>it is structured (and relatively standardized);</li>

<li>people are not shy at inputing it;</li>

<li>it is yet difficult to search on the web.</li>
</ul>

<p>So, if the semantic web could provide some help in dealing with
personal information (or PIM data here), it could prove to be
really useful right away. It could also produce high quality data
that could be used for other applications.</p>

<h3><a
href="http://www.daml.org/2002/02/dagstuhl-rules/slide10-0.html">Mike
Dean's International Meeting usecase</a></h3>

<p>When attending an event, be able to download into a Palm or
similar all the information needed about the event, for example,
maps, travel itinerary, information about the participants,
agenda.</p>

<p>[This is, I suppose, an example of what could be done with data
made available in RDF form, possibly with DAML+oil or similar
annotations. One important requirement here is that the event be
clearly identifiable, so that it can be associated with information
such as geographical location. Similarly, the other components
would also be identifiable, e.g. locations, people.]</p>

<p>Dan Brickley asked what was preventing the implementation of the
usecase now; Mike's answer was that not all the information is
available on the web, for example opening hours of hotel
restaurant, or which hotels have a high speed or wireless internet
access. This is why he has created the <a
href="http://www.daml.org/data/">DAML data page</a> - looking for
sources of useful information on the web that are both
authoritative and complete, for example, countries, airports,
companies, geographical locations.</p>

<h3><a href="http://www.w3.org/2000/10/swap/pim/travel.html">Dan
Connolly's Semantic Web travel tools page</a> - usecase -
visualizing travel information</h3>

<p>Dan Connolly is interested in travel tools: itenary
visualization, and also loading data into evolution or palm pilot
import and getting it back again. Also scraping information from
travel agent supplied text formats and emails and from html pages.
For example, take iCalendar formatted information from Evolution;
then convert the iCalendar to RDF; and then compare information
scraped from team webpages about events and see if it's missing off
the personal calendar.</p>

<p>See also <a
href="http://www.w3.org/2000/04/mem-news/teamToGlobe">rules to plot
W3C team members on a globe</a>.</p>

<p>See also <a
href="http://www.w3.org/2002/08/flight/map.svg">Charles
McCathieNevile's travel plot in SVG</a>.</p>

<h3>Libby Miller's <a
href="http://swordfish.rdfweb.org/discovery/2002/10/calwk/calwk.jsp?pics=+calendar+workshop+images+">
photos of people at this meeting demo</a></h3>

<p>This is a specific extension to Mike Dean's usecase, as
suggested by Dan Brickley, namely - I haven't most of the people
coming to this meeting - what do they look like? Also, what papers
have they written?</p>

<h3>Retsina calendar agent and restaurant location usecase</h3>

<p>The <a href="http://www.daml.ri.cmu.edu/Cal/">Retsina calendar
agent</a> has RDF processing capabilities. It can be used to read
in RDF from the <a
href="http://www.ilrt.bris.ac.uk/discovery/2001/06/schemas/ical-full/hybrid.rdf">
'hybrid' RDF calendar schema</a> and add the data to Outlook. It
can be used to do things like find restaurants local to a meeting
(via an agent) if it knows the latitude and longitude. It can also
find contacts from the data (defined using <a
href="http://xmlns.com/foaf/0.1/">foaf schema</a>).</p>

<h3>P&auml;r Lanner&ouml;'s <a
href="http://galway.metamatrix.se/skical/">SkiCal examples</a></h3>

<p><a href="http://www.skical.org/">Skical</a> is a set of
additions to iCalendar for describing public events such as
concerts, sports events. 4 years' of experience with Skical have
led to various conclusions (from <a
href="http://galway.metamatrix.se/skical/">P&auml;r's
presentation</a>):</p>

<ul>
<li>MUCH repetitive work is being done today, with faxes etc.</li>

<li>Tourism sector WANTS this, and is ready to invest some time,
and adapt their terminologies</li>

<li>But there are information brokers who do not</li>

<li>Event producers often too small to afford their own databases -
Apple iCal seems like a better model</li>

<li>Things take time :)</li>

<li>Complete language/tool not always needed (recurring events for
example)</li>

<li>MS Outlook i/vCalendar import much appreciated</li>
</ul>

<p>P&auml;r has also created <a
href="http://www.stockholmtown.com/events/skical/skicalrss.asp?date1=2002-09-02&amp;date2=2002-09-11">
an RSS+events+skical channel</a> with information provided by the
Stockholm tourist office, about events in Stockholm.</p>

<h3>Dan Brickley's dentist's opening hours usecase</h3>

<p>Dan's dentist found this image the simplest way of making public
the opening hours on the web:</p>

<img src="http://www.zetlanddental.co.uk/images/home1.gif"
alt="Zetland Denist's opening hours ('open 9-5.30 Monday to Friday, late evening and Saturday appointments by arrangement')" />

<p>Dan would like to be able to give them good advice: on making
the page look good, on accessibility, and on the Semantic Web.</p>

<h3>Joaquin Salvachua's usecase - organising a conference</h3>

<p>Organising and coordinating a conference is extremely
complicated involving the phone, WWW, with many dependencies. It's
extremely expensive. Usually consists of static web pages produced
by hand. Joaquin has written <a
href="http://iswc2002.semanticweb.org/posters/salvachua.pdf">a
poster (PDF)</a> about the application of <a
href="http://isabel.dit.upm.es/">ISABEL</a>, a Semantic Web
application to help organise conferences (PDF) shown at <a
href="http://iswc2002.semanticweb.org/">ISCW 2002</a>.</p>

<p>Another usecase and software is the result of an EC research
project, <a href="http://www.ist-universal.org/">'Universal
Brokerage Package for Learning'</a>, a broker for the interchange
of learning materials, for dynamic delivery of new content. You
need to give the students the schedule information about courses,
but you also need to combine that information with additional
information about how to connect to the class. For this reason
iCalendar isn't enough because you need to include other
information.</p>

<h3>Martin Poulter's usecase - distributing data for LTSNs</h3>

<p>The LTSN is a central clearing house for subject-specific
teaching and learning information. There are about 30 different
projects cataloging conferences and other events, all using
different underlying technologies to create, store and display the
information. A really big event could be catalogued 30 times. A
step towards interoperability is using the RSS+events module for
describing conferences and other events. It's a very simple
specification and very clearly presented, so it's simple to
implement, and the five fields cover LTSN needs very well. It has
to be simple because of the wide variety of technical help
available over the centres.</p>

<p>The aim is to merge and display events from different centres.
The disadvantage is that the events module is rather vague. In
addition it's not clear how to identify events from multiple
sources (this is a difficult philosophical problem - events can be
described in different ways - a discussion can also be an argument.
Dan Brickley suggested a possible way around: the event whose
homepage is http://foo). Dan Brickley has written <a
href="http://www.w3.org/2001/12/rubyrdf/squish/service/webfetch_tests.rb">
Ruby code</a> allowing <a
href="http://www.economics.ltsn.ac.uk/events/events.xml">LTSN event
data</a> to be cross-queried against Google backlinks. Martin would
like to be able to do things like 'notify me of economics events
associated with Bloomfield House'. Standards are very important
because of the diversity of platforms used.</p>

<h3>Kal Ahmed's usecase - making it easy for the little guy to
publish</h3>

<p>Kal's usecase was to make it as simple as possible for people to
write structured data to the web, at least a bare minimum, so that
for example you could find out where and when small touring theatre
companies are playing locally. A possible solution might be to
create forms of html which could be translated to RDF (an example
of this is immediately below).</p>

<h3>Building on the world's investment in HTML (Dan Brickley's use
case)</h3>

<p>Dan Connolly enhanced and <a
href="http://www.w3.org/2000/08/w3c-synd/">wrote up</a> something
Dan Brickley and Eric van der Vlist worked on: the <a
href="http://www.w3.org/">W3C main page</a> is marked up with a
profile of xhtml. You can use an <a
href="http://www.w3.org/2000/08/w3c-synd/home2rss.xsl">xslt
stylesheet</a> to scrape out an RSS channel.</p>

<p>Libby Miller added to this basic model to create an RSS+events
module profile, for example <a href="">SWAD-Europe events page</a>.
There's also a <a
href="../../200207/rsscal/xslt-rss-events.html">writeup of this
version</a>.</p>

<p>In both cases this technique has the advantage of storing all
information in one place rather than having separate machine and
person-readable versions which can become mismatched. in addition,
anyone who can hand code html can write web pages like this - it
does not require knowledge of RDF.</p>

<h3>Jan Grant's usecase - trust and security of information</h3>

<p>Jan made a point about security and trust, by suggesting a
query: ' find two people in a house worth 200,000 pounds where
they're both away for a week'. Even knowing where you are might be
valuable information, for example for a CEO. Dan Connolly commented
that security is the main focus of a research project at W3C -
policies about who gets to see the phone numbers of people going to
a meeting and so on.</p>

<h3><a
href="http://www.ninebynine.org/SWAD-E/Intro.html#HomeNetAccessDemo">
Graham Klyne's access control usecase</a></h3>

<p>(Not presented at the workshop)<br />
Graham has been using iCalendar/RDF data to generate Cisco IOS
configuration commands for home networking. This involves combining
information about people, network users, internet access schedules
and network device characteristics. More information is available
<a
href="http://www.ninebynine.org/SWAD-E/Scenario-HomeNetwork/HomeNetworkConfig.html">
in the documentation</a>.</p>

<h2><a id="faqs" name="faqs">FAQs</a></h2>

<h3>Where can I ask questions/find out about RDF and
calendaring?</h3>

<p>Try the <a
href="http://lists.w3.org/Archives/Public/www-rdf-calendar/">RDF
interest group's calendaring taskforce email list</a>. We're happy
to hear about projects and answer questions.</p>

<h3>What is the most widely used standard for writing up calendar
information in machine-processible format?</h3>

<p>The standard is the IETF's iCalendar and its sister RFCs. There
is a <a
href="../../200210/calendar/vocab_usecases.html#ical-rel">summary
of the relevant standards and documents and some issues</a>.</p>

<h3>Why should I use RDF for my calendar data? (especially when
there is already an established standard?)</h3>

<p>The main argument is that it is often useful to combine
calendaring information - information about the times and dates of
events - with other information such as location, people attending,
related documents. iCalendar is not designed to be extensible in
this way, although it does include some information about location.
RDF makes merging information from different sources easier.</p>

<p>Please see the <a href="#usecases">usecases</a> below for
examples of when it might be useful to use RDF calendar data.</p>

<h3>What RDF schema/vocabulary should I use?</h3>

<p>At the moment there are at least two schemas available, both
based on iCalendar. One has been termed the <a
href="http://www.ilrt.bris.ac.uk/discovery/2001/06/schemas/ical-full/hybrid.rdf">
'hybrid' RDF calendar schema</a> for obscure reasons. It was
written by Michael Arick and Libby Miller and is used in a few <a
href="http://swordfish.rdfweb.org/discovery/2001/07/swws/">demos</a>
and in the <a
href="http://www.daml.ri.cmu.edu/site/projects/RDFCalendar/">Retsina
calendar agent</a>.</p>

<p>Dan Connolly has a number of different schemas - for <a
href="http://www.w3.org/2000/10/swap/pim/ical.rdf">iCalendar</a>,
and also for the <a
href="http://www.w3.org/2000/08/palm56/datebook">Palm</a> to work
with his <a
href="http://www.w3.org/2000/08/palm56/datebook">Palmagent
software</a> which allows you to sync RDF formats with the
Palm.</p>

<p>There is also the very simple <a href="">RSS+events module</a>,
which many people find useful but which is very underspecified. Dan
Connolly has a <a
href="http://www.w3.org/2000/10/swap/test/esw2pd.n3">converter for
RSS events to Palm</a>.</p>

<p>We are in the process of working out a good process to come up
with a single vocabulary - see the <a href="#outcomes">notes
above</a>.</p>

<p>Some more information about the various vocabularies is <a
href="../../200210/calendar/vocab_usecases.html#rdf">also
available</a>.</p>

<h3>What conversion tools are available from iCalendar to RDF? from
RDF to iCalendar? RDF to HTML?</h3>

<p>Dan Connolly has <a
href="http://www.w3.org/2000/10/swap/pim/ical2rdf.pl">Perl code to
convert iCalendar to RDF</a> and also <a
href="http://www.w3.org/2002/01dc-nj/toICal.py">a python tool</a>
that converts from RDF to iCalendar ('hybrid' schema). In addition
his <a href="http://dev.w3.org/cvsweb/2001/palmagent/">Palmagent
page</a> contains XSLT for RDF version of Palm Datebook as
HTML.</p>

<p>Gary Frederick sent <a
href="http://lists.w3.org/Archives/Public/www-rdf-calendar/2002Jul/0001.html">
a message</a> about converting iCalendar to an xml format
(including Dan Connolly's version of iCalendar in RDF). XSLT to
convert to <a
href="http://www.w3.org/2000/10/swap/pim/ical.rdf">Dan Connolly's
iCalendar vocabulary</a> is now included in the Mozilla calendar
standard distribution.</p>

<h3>What tools are available that consume iCalendar data?</h3>

<p>Mozilla's calendar and Apple's iCal both consume iCalendar data
(the iPod also understands iCalendar .ics files, and you can upload
several calendars onto an iPod which will then also merge them
together for you). There's a <a href="">page</a> detailing other
implementations of iCalendar - note that many are partial
implementations. The Calsch working group (which developed
iCalendar) holds <a
href="http://www.calsch.org/CalConnect3/interop.html">interoperability
testing sessions</a>, but does not appear to publish the
performance of named products.</p>

<h3>What tools are available that consume RDF calendar data?</h3>

<p><a
href="http://www.daml.ri.cmu.edu/site/projects/RDFCalendar/">Retsina</a>
and various tools described above. You can also convert certain RDF
calendar vocabularies to iCalendar and there are many consumers of
iCalendar data.</p>

<h3>Does anyone have code that runs on Windows to dump Palm desktop
software calendar as RDF? (webcal?)</h3>

<p>Not to my knowledge, unfortunately, although there is a <a
href="http://www.ooblick.com/software/coldsync/#p5-Palm">perl
module</a> that can be used to parse Palm .pdb files to create RDF
(Libby Miller and Dan Connolly both have examples of this). Palm on
windows uses a different file format (.dba) to the internal file
format and the format used on linux (.pdb). You might be able to
get around this by using a tool like <a
href="http://perso.wanadoo.fr/fpillet/syncbuddyGB.html">Sync
buddy</a> to grab all the palm databases in their raw form off the
Palm and then use Perl; or you could use something like <a
href="http://www.geocities.com/SiliconValley/Way/4696/">this</a> -
a parser for the dba files. But - I don't know if this works, and
the <a
href="http://www.geocities.com/Heartland/Acres/3216/datebook_dat.htm">
dba files are subject to arbitrary change by Palm</a>.</p>

<h3>What's a good way of describing people, locations, events,
documents in RDF in an interoperable way?</h3>

<p>This is a tough question, because it's really about being good
at modeling information, which itself is pretty difficult. <a
href="http://www.xml.com/pub/a/2002/10/30/rdf-friendly.html">An
interesting xml.com article</a> by Bob DuCharme and John Cowan
illustrates a series of approaches you might find useful,
especially if you are used to writing XML documents. I wrote a
short piece on <a
href="http://ilrt.org/discovery/2002/04/query/#one">three practical
principles for creating interoperable data with RDF</a> [but I
should stress that that is just my personal opinion].</p>

<p>The other thing you can do is reuse RDF vocabularies (schemas)
where they are available. So for example you could use <a
href="http://purl.org/dc/elements/1.1/">Dublin Core</a> to
represent information about webpages and other documents; the
experimental <a href="http://xmlns.com/foaf/0.1/">foaf</a>
vocabulary or <a href="http://www.w3.org/TR/vcard-rdf">vCard in
RDF</a> for people, addresses, relationships. Reusing vocabularies
can be difficult if parts of a schema are similar to what you want,
but do not quite represent it exactly. RDF has <a
href="http://www.w3.org/TR/rdf-schema/#ch_subclassof">subClassOf</a>
and <a
href="http://www.w3.org/TR/rdf-schema/#ch_subpropertyof">subPropertyOf</a>
relationships to accommodate these similarities interoperably.
These are not currently processed in very many tools but are useful
for fixing the meaning of classes and properties precisely, and
will likely be used in the future.</p>

<h3>Where can I get sample data?</h3>

<p>At the moment, there's 'hybrid' data <a
href="http://www.ilrt.bris.ac.uk/discovery/2001/06/content/">at the
ILRT site</a>. You could also try searching for iCalendar
predicates at <a href="http://jibbering.com/2002/12/pred.html">Jim
Ley's RDF database</a> (<a
href="http://jibbering.com/2002/12/pred.1?predicate=http%3A%2F%2Filrt.org%2Fdiscovery%2F2001%2F06%2Fschemas%2Fical-full%2Fhybrid.rdf%23DTSTART&amp;search=">
example search</a>). Probably the best way of getting data is to
take some of the iCalendar data that's available and use the tools
available to convert it.</p>

<h3>What is the best way of representing repeating events in RDF?
[<a
href="http://lists.w3.org/Archives/Public/www-rdf-calendar/2002Dec/0000.html">
reference</a>]</h3>

<p>Recurrence is difficult to model, and there are <a
href="../../200210/calendar/vocab_usecases.html#recur">some
problems with the iCalendar notion of recurrence</a>. The hybrid
iCalendar RDF model repeats the iCalendar model (and probably its
errors). Greg Fitzpatrick has proposed <a
href="http://www.idealliance.org/papers/xml2001/papers/html/05-04-06.html">
a more elegant model for recurrence</a>.</p>

<h2><a id="attendees" name="attendees">Attendees</a></h2>

<ol>
<li>Andy Seaborne mailto:andy.seaborne@hp.com</li>

<li>Antonio Cavedoni mailto:antonio@cavedoni.org</li>

<li>Chris Croome mailto:chris@webarchitects.co.uk</li>

<li>Dan Connolly mailto:connolly@w3.org</li>

<li>Dan Brickley mailto:danbri@w3.org</li>

<li>Damian Steer mailto:dsteer@hp.com</li>

<li>Graham Klyne mailto:gk-esw-cal@ninebynine.org</li>

<li>Greg Fitzpatrick mailto:greg@skical.org</li>

<li>Jan Grant mailto:jan.grant@bristol.ac.uk</li>

<li>Jos de Roo mailto:jos.deroo.jd@belgium.agfa.com</li>

<li>Kal Ahmed mailto:kal@techquila.com</li>

<li>Emmanuel Korie mailto:koriee@hotmail.com</li>

<li>Libby Miller mailto:libby.miller@bristol.ac.uk</li>

<li>Martin L Poulter mailto:m.l.poulter@bristol.ac.uk</li>

<li>Mike Dean mailto:mdean@bbn.com</li>

<li>Max Froumentin mailto:mf@w3.org</li>

<li>P&auml;r Lanner&ouml; mailto:par.lannero@metamatrix.se</li>

<li>Pat Hayes mailto:phayes@ai.uwf.edu</li>

<li>Trevor Martin mailto:trevor.martin@bristol.ac.uk</li>

<li>Terry Payne mailto:trp@ecs.soton.ac.uk</li>

<li>Joaquin Salvachua mailto:jsr@dit.upm.es</li>
</ol>

<p>Unfortunately,<br />
David Colombi mailto:d.colombi@swap.ac.uk<br />
Edd Dumbill mailto:edd@usefulinc.com<br />
Monika Solanki mailto:monika@dmu.ac.uk<br />
were unable to attend.</p>

<p>A list of participants and their photos is available <a
href="http://swordfish.rdfweb.org/discovery/2002/10/calwk/calwk.jsp?pics=+calendar+workshop+images+">
here</a>. Photos from the day are available <a
href="http://swordfish.rdfweb.org/photos/2002/10/09/">here (by
Libby Miller)</a> and <a
href="http://lannero.com/p/bristol2002/">here (by P&auml;r
Lanner&ouml;)</a>.</p>

<h2><a name="tools" id="tools">Appendix A: Projects and
Tools</a></h2>

<h4>Apple <a href="http://www.apple.com/ical/">iCal</a>, <a
href="http://www.icalshare.com/">iCalshare</a></h4>

<p>Damian Steer demoed the Mac OS X calendar tools. You can create
a calendar entry and publish it to the web via WebDav to mac.com is
iCalendar. to the Web via WebDAV to mac.com. Dan Connolly noted
that he had heard that that the protocol doesn't require anything
outside HTTP 1.1 PUT.</p>

<h4><a href="http://www.mozilla.org/projects/calendar/">Mozilla
calendar project</a></h4>

<p>The Mozilla calendar project also uses iCalendar. We had some
success with interoperability - creating a calendar entry in Apple
iCal and reading it into Mozilla. There's active and interesting
work going on here - see the <a
href="news://news.mozilla.org/netscape.public.mozilla.calendar">news
group</a>, <a
href="mailto:mozilla-calendar-request@mozilla.org?subject=subscribe">
mailing list</a> and <a href="irc://irc.mozilla.org/calendar">irc
channel</a>.</p>

<h4>PIM tools</h4>

<p>Dan Connolly has made some interesting personal information
management tools. <a
href="http://dev.w3.org/cvsweb/2001/palmagent/">Palmagent</a> is
perl code which can export the Palm Datebook as RDF using
Palm::Datebook.pm; format the RDF datebook as HTML; serve
DatebookDB.pdb as RDF via HTTP.</p>

<p>He has also written a <a
href="http://www.w3.org/2000/10/swap/pim/travel.html">Semantic Web
travel tools page</a> - uses CWM, XSLT to parse legacy data,
display it as SVG and as xearth, and convert to the palm pilot
datebook format.</p>

<h4>Gary Frederick's XSLT</h4>

<p>Gary Frederick who works on the Mozilla Calendar project sent <a
href="http://lists.w3.org/Archives/Public/www-rdf-calendar/2002Jul/0001.htm">
a message</a> about converting iCalendar to an xml format
(including Dan Connolly's version of iCalendar in RDF).</p>

<h4><a href="http://www.daml.ri.cmu.edu/Cal/">Retsina calendar
agent</a></h4>

<p>Rahul Singh and Terry Payne developed the Retsina calendar agent
to allow you to import RDF calendar data into Microsoft Outlook. It
can also find related information for you - such as local
restaurants, where location information is available. <a
href="http://www.daml.ri.cmu.edu/site/projects/RDFCalendar/">More
information is available</a>.</p>

<h4><a href="../../200207/rsscal/xslt-rss-events.html">RSS+events
module XSLT tools</a></h4>

<p>This uses <a href="../../events/home2rss.xsl">an XSLT file</a>
to parse <a href="../../events/Overview.html">a profile of
XHTML</a> to produce <a
href="http://www.w3.org/2000/06/webdata/xslt?xslfile=http://www.w3.org/2001/sw/Europe/events/home2rss.xsl&amp;xmlfile=http://www.w3.org/2001/sw/Europe/200211/swconferences/events1.html">
an RSS 1.0+events file</a> which can be <a
href="http://www.w3.org/2001/sw/Europe/events/view/">displayed</a>. <a
href="http://www.w3.org/2000/09/calendar/alpha1">Charles
McCathieNevile has also done some early work in this area</a>.</p>

<h4><a
href="http://swordfish.rdfweb.org/rdfquery/">SquishQL/InklingRDF
query</a> <a
href="http://swordfish.rdfweb.org:8085/index.html#calendar">calendar
experiments</a></h4>

<p>These experiments and demonstrators illustrate the use of a
simple SQL-like RDF query language to query and display calendar
information.</p>

<h4><a
href="http://www.ilrt.bristol.ac.uk/discovery/rdf-dev/rudolf/js-rdf/index.html">
Calendar demo using Javascript prolog</a></h4>

<p>Jan Grant wrote an implementation of prolog in Javascript. This
demonstrator by Dan Brickley shows how you can find out things like
who is busy at certain times using information scraped from <a
href="http://www.w3.org/XML/2000/04soccer-sched/pre-k.html">html</a>.</p>

<hr />
<h3>Resources</h3>

<h4>ICalendar and related</h4>

<p><a href="http://www.ietf.org/rfc/rfc2445.txt">iCalendar RFC
2445</a><br />
<br />
<a href="http://www.calsch.org/">CalSch working group</a><br />
<br />
<a href="http://www.calsch.org/icalsite.html">A List of iCalendar
services and applications</a> <a
href="http://www.wfu.edu/~rbhm/cal.html">and another
list</a>.<br />
<br />
<a href="http://www.ietf.org/rfc/rfc2446.txt">iTip (RFC
2446)</a><br />
<br />
<a href="http://www.ietf.org/rfc/rfc2447.txt">iMip (RFC
2447)</a><br />
<br />
<a href="http://www.ietf.org/rfc/rfc2739.txt">Calendar attributes
for vCard and LDAP RFC 2739</a><br />
<br />
<a href="http://www.ietf.org/rfc/rfc3283.txt">Guide to internet
calendaring RFC 3283</a><br />
<br />
<a
href="http://www.ietf.org/internet-drafts/draft-ietf-calsch-cap-08.txt">
CAP</a><br />
<br />
<a
href="http://www.ietf.org/internet-drafts/draft-ietf-calsch-many-xcal-02.txt">
iCalendar DTD (xCalendar)</a><br />
<br />
<a href="http://www.ietf.org/rfc/rfc2234.txt">ABNF notation (RFC
2234)</a><br />
<br />
<a href="http://www.ietf.org/rfc/rfc2425.txt">Mime Directory
format</a><br />
<br />
<a
href="http://www.imc.org/ietf-calendar/mail-archive/msg00222.html">Recurrence
issues</a> <a
href="http://www.imc.org/ietf-calendar/mail-archive/msg00223.html">continued</a>
<a
href="http://www.imc.org/ietf-calendar/mail-archive/msg00623.html">and
more</a>.<br />
<br />
<a
href="http://www.idealliance.org/papers/xml2001/papers/html/05-04-06.html">
Greg Fitzpatrick's 'Orlando' recurrence model</a><br />
<br />
<a href="http://www.cse.ucsc.edu/~marick/iCalendarUML.html">Michael
Arick's iCalendar in UML</a><br />
<br />
<a href="http://www.wfu.edu/~rbhm/cal.html">iCalendar Use</a> <a
href="http://www.imc.org/pdi/vcalwhite.html">more iCalendar
use</a>, <a
href="http://reefknot.sourceforge.net/bootstrap-guide/t1.html">more</a>.<br />

<br />
<a
href="http://www.ietf.org/internet-drafts/draft-many-ical-ski-05.txt">
SkiCal internet draft</a> and <a
href="http://www.skical.org">SkiCal homepage</a><br />
<br />
<a href="http://www.w3.org/TR/NOTE-datetime">W3C Date and Time
formats</a></p>

<h4>RDF and calendaring</h4>

<p><a href="http://www.w3.org/2000/01/foo">A quick look at
iCalendar, Tim Berners-Lee</a><br />
<br />
<a
href="http://lists.w3.org/Archives/Public/www-rdf-interest/2000Aug/0109.html">
Skical in RDF</a><br />
<br />
<a
href="http://ilrt.org/discovery/2001/06/schemas/ical-full/hybrid.rdf">
'hybrid' RDF calendar model</a> <a
href="http://ilrt.org/discovery/2001/06/schemas/ical-full/old/">old
versions</a><br />
<br />
<a
href="http://lists.w3.org/Archives/Public/www-rdf-calendar/2002Sep/0007.html">
problems with the hybrid model</a>, <a
href="http://lists.w3.org/Archives/Public/www-rdf-calendar/2002Sep/0012.html">
more problems</a><br />
<br />
<a href="http://www.daml.org/">DAML+oil</a><br />
<br />
<a href="http://dev.w3.org/cvsweb/2001/palmagent/">Palmagent</a>,
<a
href="http://dev.w3.org/cvsweb/~checkout~/2001/palmagent/icalVocab.rdf?rev=1.3&amp;content-type=text/xml">
Palmagent icalendar vocabulary</a> <a
href="http://www.w3.org/2000/08/palm56/datebook.rdf">Palm RDF
voabulary</a><br />
<br />
<a href="http://www.purl.org/rss/1.0/">RSS 1.0</a>, and <a
href="http://web.resource.org/rss/1.0/modules/event/">RSS events
module</a><br />
<br />
<a
href="http://developer.ximian.com/articles/whitepapers/calendar/">Ximian
Evolution Calendaring Framework</a></p>
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