Semantic Web Best Practices and Deployment Working Group

Ontology Engineering and Patterns Task Force (OEP)

This page: Notes | Working Drafts | Editor's Drafts | Planned Notes | Suggested Notes | Telecons | Membership

Nearby: SWBPD

The aim of this task force is to provide guidance for developers of Semantic Web applications. In particular, we focus on the engineering of semantic web ontologies, through the publication of notes that document common and reusable ontology patterns, and general ontology engineering best practices.

Published Notes

These W3C notes are in their final and published form.

• Representing Classes As Property Values on the Semantic Web
  W3C Working Group Note 5 April 2005, Noy (ed.)
  (editor's draft)
• Representing Specified Values in OWL: "value partitions" and "value sets"
  W3C Working Group Note 17 May 2005, Rector (ed.)
  (editor's draft)

Working Drafts

These W3C Working Drafts have been formally reviewed by the SWBPD WG in one form or another, though the editor's drafts may represent significant changes from the last reviewed WD.

• Defining N-ary Relations on the Semantic Web: Use With Individuals
  W3C Working Draft 21 July 2004, Noy and Rector (eds.)
  (editor's draft)
  Status: New version due out soon.

Editor's Drafts

These editor's drafts are undergoing or awaiting review by the WG.

• Simple Part-Whole Relations in OWL ontologies
  Rector & Welty (eds.)
  (editor's draft)
  Status:Reviewed and ready for note status - requires html cleanup.
  
• Qualified cardinality restrictions (QCRs).
  Schreiber & Rector (eds.)
  (editor's draft)
  Status: Needs final cleanup and incorporation of responses to reviews by Alistair and Jeff.
• Time.
  Hobbs & Pan (eds.)
  Currently two notes: OWL-Time (editor's draft) and Time Zones (editor's draft).
  Status: Awaiting first review - leave as two notes or merge into one?.
• Semantic Integration
  Menzel & Uschold (eds. )
  (editor's draft)
  Status: Still in early draft.
  

Planned Notes

These are notes that do not have a first draft, but have a volunteer as editor, and are therefore expected to become notes.

• Fluents.
  Editor: Chris Welty Contributors: Alan Rector, Evan Wallace, Deborah McGuinness.
  Status: Draft in progress.
  Synopsis: Closely tied to the notion of time is being able to say that a binary property "holds" for a time. e.g. one may want to say that "Chris is a member of the W3C from Sept, 2004 - Sept 2005". A property like memberOf is a fluent because it can be said to hold at a time (this is not strictly a correct definition, but it will suffice). While OWL-Time let's you represent a time interval like "Sept, 2004-Sept, 2005", it remains neutral wrt what happens at or during such a time interval. The typical move in FOL is to use a function or add an argument to the predicate, e.g. memberOf(Chris, W3C, time-interval-1), however clearly we can't do that in OWL or RDF, since we are limited to binary predicates. One solution is to go for full reification of fluents, as in the exsiting not on n-ary relations, however there are some other choices.
• Units and measures.
  Editors: Elisa Kendall and Evan Wallace. Status:Collecting existing material.
  Synopsis: An ontology of units and measures in OWL. There has been a lot of demand and much existing work on this, including in Cyc, Tom Gruber's ontology in Ontolingua, and Helena Sofia-Pinto did one for the old SUO effort.

Suggested Note Topics

These are topics for OEP notes that have been suggested, and are considered useful by the task force, but do not yet have a volunteer as editor.

• Deeper note on part-whole relations.
  Editor: Alan Rector. Contributors: Chris Welty.
  Status: Work expected to begin in 2005.
  Synopsis: A note laying out the classic distinctions, pointing to the the literature on merology, and pointing out things like that most users of partonomy probably want something that is time specific - X is a part of Y at some implied time T (the type is a part of the car now, but it may not be after the tyre has been changed) - or normative (Xs are considered parts of Ys). You need one or the other to avoid getting into issues about amputated fingers, cat's tails, etc. Also I think we have to say that this area is far from settled so we are giving guidance on workable principles plus caveats for controversies. Implementation mechanisms. Transitive properties for simple things. SEP triples are related trickse. RegionOfFrance = France or restriction(is_geographical_region_of someValuesFrom(France))]  Property hierarchies showing different relations between containment, location and partonomy. Also warnings that with current classifiers (possibly excepting FaCT++ but we aren't sure yet) large ontologies containing extensive networks linked by both has_part and is_part_of (or any other transitive relation and its inverse) are potentially combinatorially explosive. If anybody does try to use a classifier it is disconcerting to see what seemed to work for a toy run indefinitely for something real. Transitive properties and part-of - A simple example schema for different kinds of parthood, containment, location, membership, etc. showing the use of the property hierarchy. Were I to do it, I would adapt the scheme in http://www.cs.man.ac.uk/~rector/ontologies/simple-top-bio/
• Subjects.
  Status: Chris will lead, to start after Fluents.
  Synopsis: The notion of what a subject "is" and what the "subjectOf" relation means can be quite confusing.
• Space.
  Status: Pat to lead. First draft by end of February.
  Synopsis: The need for a note on "time" clearly suggests the need for an analogous note on space. Tony Cohn and colleagues have done a lot of good work in this area, as have others. It would be useful to do for RCC (the region connection calculus) what OWL-Time did for the Allen Temporal Calculus.
• Ontology 101 tutorial specifically for OWL/RDF.
  Status: Alan to compose a set of options for what to do.
  Synopsis: Pizza tutorial and wines tutorial. The quesiton here is what to include from all the existing materials such as: http://www.co-ode.org/resources/tutorials/ProtegeOWLTutorial.pdf ( more presentations and papers: http://www.co-ode.org/resources/ ) Alan will post ontologies and ISWC-04 slides.
• How semantics came to mean ontology
  Status: Chris to work on
  Synopsis: People who know what "ontology" and "semantics" actually mean (in the much larger world outside of computer science), often ask why the two have become nearly synonymous on the semantic web. Personally, I think its a fair question and a short note on why we're so confused would be worthwhile. Maybe this goes in another task force (wasn't there a clean up the mess we've made task force?)
• options for using Ontologies in applications
  Status: Deborah and Mike perhaps to work on in 2005.
  Synopsis: Whether in OWL or RDF - this is the thing the SWBP really has to crack. Picking up where Classes as Values left off. I am not sure where pointers to specific tricks with current technology fit in, but in the "deployment" part of SWBP&D I think many people would welcome a list of tool combinations that were known to work, however time limited that list will inevitably be. I am certainly not in a position to produce such a list; I don't think the list per se is really part of OEP, but we need someplace where we coordinate the principles the notes with practice..
• When to use a reasoner and normalisation.
  Status: AlanR plans for early spring.
  Synopsis:
• Common pitfalls
  Status: AlanR is trying to recruit someone (Heiwong)
  Synopsis:
• Numeric ranges
  Status: Guus has a draft. Waiting for XMLS TF
  Synopsis: Lots of issues regarding solving this problem in XMLS, e.g. what is a URI for a user defined data type.
• Closing axioms
  Status: Deborah McGuinness to draft.
  Synopsis: An initial limited description (with follow-up discussion) is available from the mailing list posting http://lists.w3.org/Archives/Public/public-swbp-wg/2004Oct/0052.html. One of the benefits of working with a language that allows for open world reasoning, is that reasoners do not make closed world assumptions. Thus, it is sometimes important to state that there will be no additional values filling a slot so that reasoners can make inferences based on current values and their properties. This note discusses approaches to the problem and provides examples.
• Domain and Range restrictions
  Status:
  Synopsis: Very important, lots of confusion. Note should say what to expect, focus on the difference between frames/OO and OWL.
• Multiple types
  Status: AlanR will take the lead.
  Synopsis:
• From UML to OWL
  Status: Dropped due to OMG work
  Synopsis:

Scheduled telecons

The Task Force meets on alternate Mondays at 1800 UTC. This is the same slot as the Working Group telecon but on the alternate weeks: 30 Jan, 13 Feb, 27 Feb, 13 Mar, 27 Mar, 10 Apr, 24 Apr.

Table of Time Zone Conversions for UT

The OEP Task Force members are:

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