Thanks, Mike. Can you point us to the discussion archives ref. this
topic, please. =ppy
-- (01)
On Mon, Nov 10, 2008 at 6:41 PM, Michael F Uschold <uschold@xxxxxxxxx> wrote:
> This discussion is already taking place on the semantic web forum. No sense
> in having it be in two places, methinks.
>
> semantic-web@xxxxxx
>
> Michael (02)
> On Fri, Nov 7, 2008 at 8:47 AM, Peter Yim <peter.yim@xxxxxxxx> wrote:
>>
>> Mike Uschold was just talking about this subject matter (a week or so
>> ago) in his lightning talk called "A URI Crisis" at ISWC 2008 (at
>> Kar;sruhe, see:
>>
>>
>http://ontolog.cim3.net/file/resource/pic/iswc2008_Karlsruhe_Oct-2008/images/P1010167.jpg
>> ).
>>
>> Since the issue is definitely of concern and interest to the broader
>> Ontolog community, may I suggest we move the conversation to
>> [otnolog-forum] where Mike can also chime in ... since he started it
>> all. (I'll forward this thread over ... pick it up from there, if you
>> please.)
>>
>> Regards. =ppy
>> --
>>
>>
>> On Fri, Nov 7, 2008 at 7:57 AM, Evan Wallace <ewallace@xxxxxxxxxxxx>
>> wrote:
>> > In the Semantic Web or when using semantic web languages, the primary
>> > names/identifiers for classes,
>> > properties and individuals (instances) are http URIs . This is
>> > fundamental to the languages and the way
>> > tools support the languages. RDF data and OWL ontologies are typically
>> > stored and accessed as web
>> > documents (and OWL imports is the typical mechanism used for
>> > modularizing this information). The
>> > RDF data model is triple based and the OWL model is axiom based. How one
>> > would make these languages
>> > and their tools work with the Object Oriented approach and services in
>> > the Handle System is far from obvious.
>> > Am I missing something? Is there a document describing how these things
>> > could be used together? Until
>> > I see a document describing how this would work, I don't see how the
>> > Handle System will help manage
>> > identifiers or any other information for semantic web resources.
>> >
>> > -Evan
>>
>>
>> >> ----------
>> >> From: John F. Sowa <sowa@xxxxxxxxxxx>
>> >> Date: Thu, Nov 6, 2008 at 11:17 PM EST
>> >> Subject: Re: [oor-forum] FW: URIs and Unique IDs
>> >> To: OpenOntologyRepository-discussion <oor-forum@xxxxxxxxxxxxxxxx>
>> >>
>> >>
>> >> Leo and Steve,
>> >>
>> >> For naming schemes, there are only two options:
>> >>
>> >> 1. Free for all naming scheme (e.g., people can name themselves
>> >> and their children, pets, cities, etc., anything they please).
>> >>
>> >> 2. Regimented naming scheme (some constraints imposed).
>> >>
>> >> Option #1 usually results in multiple entities with the same
>> >> names. Option #2 requires some kind of centralized registry
>> >> system that enforces whatever constraints are agreed.
>> >>
>> >> The simplest kind of constraint is something like GENSYM in LISP.
>> >> Each time it is called, it generates a symbol that is guaranteed
>> >> to be distinct from every other symbol it has ever generated.
>> >>
>> >> But for many kinds of things, such as people, computer programs,
>> >> and ontologies, we may need some kind of versioning mechanism.
>> >> We might want to talk about some specific version of Linux,
>> >> or we might want to refer to some person as a child or an adult.
>> >>
>> >> Before we can even begin to talk about a registry for handling
>> >> versions, we have to agree on a lot of identity criteria.
>> >>
>> >> When are two ontologies versions of one another? How different
>> >> do two versions have to be before they are considered distinct?
>> >> Who decides?
>> >>
>> >> John
>>
>>
>> >> ----------
>> >> From: John Graybeal <graybeal@xxxxxxxxx>
>> >> Date: Thu, Nov 6, 2008 at 7:45 PM PST
>> >> Subject: Re: [oor-forum] FW: URIs and Unique IDs
>> >> To: ray@xxxxxxxx, OpenOntologyRepository-discussion
>> >> <oor-forum@xxxxxxxxxxxxxxxx>
>> >>
>> >>
>> >> For what little it's worth, I've taken a moderately detailed look at
>> >> handles, and I reached the same conclusion some others have:
>> >> it moves the existing problems of URIs around to other parts of
>> >> the architecture, but doesn't fundamentally eliminate any of them,
>> >> and doesn't provide enough capability improvements or social
>> >> improvements to outweigh the social and adoption costs. (It may
>> >> be better than minted URIs -- it wasn't obviously better to me,
>> >> but I'm not an expert -- but I thought not sufficiently better to
>> >> abandon minted URIs.)
>> >> I'll be interested to hear others' reactions. I think it may have been
>> >> discussed on the semantic-web list, so might be worth checking
>> >> the archives before posting.
>> >> John
>>
>>
>> > Steve Ray wrote Thu, Nov 6, 2008 at 7:30 PM EST:
>> >>
>> >> For identifier resolution, it could work for a variety of things, so
>> >> sure.
>>
>>
>> >> *From:* Obrst, Leo J. [mailto:lobrst@xxxxxxxxx]
>> >> *Sent:* Thursday, November 06, 2008 6:40 PM
>> >> *To:* ray@xxxxxxxx; OpenOntologyRepository-discussion
>> >> *Subject:* RE: [oor-forum] FW: URIs and Unique IDs
>> >>
>> >> Steve,
>> >>
>> >> Thanks. Do you think this would be useful for the Semantic Web
>> >> community too? I.e., should this be pushed to the semantic-web@xxxxxx
>> >> <mailto:semantic-web@xxxxxx> list?
>> >>
>> >> Thanks,
>> >>
>> >> Leo
>> >>
>> >> _____________________________________________
>> >> Dr. Leo Obrst The MITRE Corporation, Information Semantics
>> >> lobrst@xxxxxxxxx Information Discovery & Understanding, Command and
>> >> Control Center
>> >>
>> >> Voice: 703-983-6770 7515 Colshire Drive, M/S H305
>> >> Fax: 703-983-1379 McLean, VA 22102-7508, USA
>>
>>
>> >> *From:* oor-forum-bounces@xxxxxxxxxxxxxxxx
>> >> [mailto:oor-forum-bounces@xxxxxxxxxxxxxxxx] *On Behalf Of *Steve Ray
>> >> *Sent:* Wednesday, November 05, 2008 7:02 PM
>> >> *To:* 'OpenOntologyRepository-discussion'
>> >> *Subject:* Re: [oor-forum] FW: URIs and Unique IDs
>> >>
>> >> I think we should be taking a hard look at Bob Kahn's ideas of the
>> >> Handle System. Take a look at http://www.doregistry.org. His idea of
>> >> handles bypasses URLs and DNS and provides a clean resolution system
>> >> at the object level, which would appear to work nicely with
>> >> ontologies, and pieces of ontologies. One would still have to ensure a
>> >> clean configuration management system ran on top of it all.
>> >>
>> >> - Steve
>>
>>
>> ---------- Forwarded message ----------
>> From: Obrst, Leo J. <lobrst@xxxxxxxxx>
>> Date: Fri, Oct 31, 2008 at 10:32 AM
>> Subject: [oor-forum] FW: URIs and Unique IDs
>> To: OpenOntologyRepository-discussion <oor-forum@xxxxxxxxxxxxxxxx>
>>
>>
>> I'm cross-posting this. Versioning is definitely an issue we need to
>> address for OOR, and though we may derive our methods from others, we
>> should certainly consider the ramifications now.
>>
>>
>>
>> Leo
>>
>>
>>
>> _____________________________________________
>> Dr. Leo Obrst The MITRE Corporation, Information Semantics
>> lobrst@xxxxxxxxx Information Discovery & Understanding, Command and
>> Control Center
>>
>> Voice: 703-983-6770 7515 Colshire Drive, M/S H305
>> Fax: 703-983-1379 McLean, VA 22102-7508, USA
>>
>>
>> From: semantic-web-request@xxxxxx [mailto:semantic-web-request@xxxxxx]
>> On Behalf Of Michael F Uschold
>> Sent: Thursday, October 30, 2008 5:15 AM
>> To: semantic-web@xxxxxx
>> Cc: aldo.gangemi@xxxxxxxxx; Conor Shankey; Peter Mika; Ora Lassila;
>> Pan, Dr Jeff Z.; Tim Berners-Lee; Frank van Harmelen;
>> sean.bechhofer@xxxxxxxxxxxxxxxx
>> Subject: URIs and Unique IDs
>>
>>
>>
>> I'm resending this message to the semantic web discussion group for the
>> record.
>>
>> On Wed, Oct 29, 2008 at 3:53 PM, Michael F Uschold <uschold@xxxxxxxxx>
>> wrote:
>>
>> Currently there is no accepted practice on how/whether to migrate to
>> new URIs when a new version of an ontology is published. This is
>> largely due to the fact that there is no good technology for managing
>> versioning, and the W3C consciously (and probably sensibly) decided
>> not to address the issue. Versioning information is meant to be
>> placed on a version annotation.
>>
>> However the current situation is like the wild West, and everyone will
>> be doing different things, resulting in a mess.
>>
>> Wordnet published a new version and minted all new URIs even though
>> many or most of the entries were semantically identical.
>> The SKOS working group is currently considering the pros and cons of
>> various options. One is to adopt all new URIs in a new namespace, just
>> like Wordnet. Another is to keep the exact same name space, and change
>> the semantics of a small number of terms while keeping the same URI. A
>> third is to keep the same URI for the unchanged terms, and mint new
>> URIs for the terms with different semantics.
>>
>> This is a problem because they have no guidelines, they are basically
>> stumbling along in the dark.
>>
>> I believe that this is an urgent matter that needs attention to
>> prevent a nightmare from unfolding.
>>
>> In the current state of semantic web use, it may not matter to much
>> what choice the SKOS team chooses. This is mainly relatively few
>> applications will be impacted, which may be due to the fact that the
>> applications are not driven by the ontologies.
>>
>> However, when usage of ontologies and ontology-driven applications
>> becomes more mainstream, the differences could be profound. Given that
>> this issue is intimately tied up with versioning, and that we have no
>> good solutions yet, do we continue to throw our hands up and punt?
>> Absolutely not, it is essential that a good precedent is set ASAP that
>> is based on sound principles.
>>
>> Here is how.
>>
>> We should imagine a future where ontology versioning is handled
>> properly and do things that are going to make things easy to migrate
>> to that future. We don't know how the versioning black box will work,
>> but we should be able to make some clear and definitive statements
>> about WHAT it does.
>>
>> For example, in the future, ontology-driven applications will be
>> fairly mainstream. URIs are used as unique identifiers. When
>> applications are driven from ontologies, then they will break if you
>> change the semantics in mid-stream. Imagine an application that
>> relied on the semantics of broader as it was originally specified with
>> transitivity. They loaded data that was created using that semantics.
>> Then the SKOS spec changes and broader is no longer transitive. New
>> datasets are created according to this new meaning. The application
>> loads more data. It needs to know which data is subject to transitive
>> closure and which is not. This is impossible, if the same SKOS URI is
>> used for versions with different semantics. They are different
>> beasts, and thus MUST have different URIs.
>>
>> Similarly, if SKOS mints a whole new namespace and changes all the
>> URIs, the application also has a problem. It has datasets with the old
>> URI and datasets with the new URIs. This means that the datasets will
>> not be linked like they should, they will treat the two different URIs
>> for the same thing as being different. If one wanted to go into
>> OWL-Full, one can use owl:sameAs, but this is not very practical. The
>> only reasonable solution is to have the same URI for things with the
>> same semantics.
>>
>> Thus, any ontology versioning systemof the future will rely on these
>> two principles:
>> 1. If the semantics of a term changes, then it needs to have a new unique
>> ID.
>> 2. If the semantics of a term does NOT change, then it should maintain
>> the same ID in any future versions.
>>
>> If either of these two guidelines are broken, then so will the
>> ontology-driven applications of the future.
>>
>> These maxims hold without exception for any standards that are
>> formally released as standards.
>> A question arises if we need to hold to the same standards for
>> standards like SKOS which was never formally blessed.
>>
>> The practical difficulties will be the same whether the standard is
>> blessed or not. It only really depends on whether the standard is a de
>> facto standard,or whether it is getting significant use. If users
>> build things and ontology producers break things through carelessness,
>> this will hinder semantic web technology adoption.
>>
>> Another question is what to do if the original standard is belived to
>> be incorrect, and the new one is the fixed one. Can one then keep the
>> same URI?
>> Again, the answer should be informed by the impact on applications.
>> The same problems will occur if you change the semantics and keep the
>> same URI even if you are fixing a mistake. The URI with the wrong
>> semantics must keep its original unique ID.
>>
>> Michael Uschold
>> ---
>>
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