Pat, (01)
Cassidy, Patrick J. wrote: (02)
>Patrick,
>
>[PD] > Why would I have to know the equivalent mappings in all the
>other
>
>
>>ontologies? (serious question)
>>
>>If I trust your mapping of ontology A to ontology B, and I
>>want to map
>>ontology C to B, why do I need to take the extra step of
>>understanding A?
>>
>>
>>
> All I can say is "good luck". The ontologies I have seen that do a
>proper job of even the most basic inheritance are rare, and if you are
>willing to trust a lot of mappings without reviewing them yourself,
>well, "good luck". Maybe someday there will be acknowledged
>well-constructed ontologies with accurate mappings, and trustable
>authoritative sources. I don't expect to live that long, and I can
>think of a lot easier way to get the accurate interoperability I need.
>
>[PD] > So if I trust a mapping of term A to term B, then would you
>
>
>>agree that I
>>can map term C to B without encountering the problem you describe?
>>
>>
>>
>No. As I said, any difference in the relational structure (which means
>any difference *at all* in the ontology) will lead to different
>inferences. The interoperability I want is to be able to draw the same
>inferences from the same data. Mapping different ontologies won't
>achieve that. If the differences are few (for the ontologies I have
>seen they will be many), then differences in inferences that are
>important may not show up often, like subtle bugs in a computer
>program. But they will be there. If you are going to rely on your
>ontology for anything really important, mapping is a way to incur great
>risk.
>
>
>
When you say: (03)
"The interoperability I want is to be able to draw the same
inferences from the same data." (04)
I take it you mean that you want one and only one set of inferences that
you have approved for your ontology? (05)
That some other ontology might draw different inferences is simply
irrelevant. (Not simply different formally but different for instance in
saying that some term is a subclass of a term (or its equivalent) that
does not appear in your ontology.) (06)
That is not a criticism but I am simply trying to uncover what you seem
to be assuming as given. (07)
>Good grief, why accept, after a great deal of effort, a product that is
>known to be defective and unreliable, when there is a straightforward
>way to avoid it? I don't want to play games with my ontology, I want
>to be able to rely on it for important decisions. If that means
>accepting a manner of representation that is not my personal
>preference, well that is a very tiny price to pay for the great
>benefit.
>
>
>
Sorry, I missed what product you were describing? (08)
BTW, the Metadata SC (of the ODF TC) in OASIS that I chair is just about
finished a proposal that enables the inclusion of RDF/XML metadata in
OpenDocument Format files. In fact, anything to which metadata can be
attached can accept multiple metadata statements, even from different
ontologies. (09)
Simply because the information from "another" ontology or its inferences
are present doesn't mean you have to use them. (010)
If you don't want to see some ontology or use its inferences, simply
don't look. (011)
Hope you are having a great day! (012)
Patrick (013)
>Pat
>
>Patrick Cassidy
>CNTR-MITRE
>260 Industrial Way West
>Eatontown NJ 07724
>Eatontown: 732-578-6340
>Cell: 908-565-4053
>pcassidy@xxxxxxxxx
>
>
>
>
>>-----Original Message-----
>>From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
>>[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of
>>Patrick Durusau
>>Sent: Thursday, May 03, 2007 12:51 PM
>>To: [ontolog-forum]
>>Subject: Re: [ontolog-forum] A "common basis"
>>
>>Pat,
>>
>>Cassidy, Patrick J. wrote:
>>
>>
>>
>>>Actually, N^2 applies to the terms of ontologies also. The notion
>>>
>>>
>of
>
>
>>>using existing equivalence of two terms in two ontologies to
>>>
>>>
>>reduce the
>>
>>
>>>effort of mapping might work, but only partly because:
>>> (1) one has to know the equivalence mapping in all the other
>>>ontologies -- not a trivial amount of work, and certainly not 0. If
>>>there are a large number of ontologies, one has to inspect the
>>>equivalence mappings of **every one**!! Try it, you won't like it.
>>>
>>>
>>>
>>>
>>Why would I have to know the equivalent mappings in all the other
>>ontologies? (serious question)
>>
>>If I trust your mapping of ontology A to ontology B, and I
>>want to map
>>ontology C to B, why do I need to take the extra step of
>>understanding A?
>>
>>
>>
>>> (2) exact equivalence of intended meaning occurs in probably less
>>>than half the terms in any two ontologies, and there is often
>>>
>>>
>meaning
>
>
>>>overlap which is much more work to reduce
>>>
>>>
>>>
>>>
>>Hmmm, so is it fair to say that at least part of the problem
>>arises due
>>to the complexity of the ontologies? That is to say the more terms an
>>
>>
>
>
>
>>ontology covers the more difficult it is to reconcile
>>different ontologies?
>>
>>
>>
>>> (3) *any* structural difference (difference in the
>>>
>>>
>>relations) of two
>>
>>
>>>terms in two ontologies will make them formally different (different
>>>inferences) even if their intended meanings are the same.
>>>
>>>
>>>
>>>
>>>
>>So it would not be helpful in some cases to know the inferences in
>>different ontologies for the same terms? Granted that it would be
>>possible to reconcile them but what if I wanted to preserve them?
>>
>>
>>
>>> Even if it seemed to work on a very small number of
>>>
>>>
>>ontologies, it
>>
>>
>>>is totally impractical when you get over 10. If you know of
>>>
>>>
>>an example
>>
>>
>>>where it has been done, let us know.
>>>
>>>
>>>
>>>
>>>
>>Oh, I am not disagreeing that what you propose would be a lot of
>>
>>
>work.
>
>
>>But it does involve the assumption that one wants to merge ontologies
>>
>>
>
>
>
>>that represent an entire world view (or a substantial part thereof),
>>which I don't doubt for a moment would be quite complicated.
>>
>>So if I trust a mapping of term A to term B, then would you
>>agree that I
>>can map term C to B without encountering the problem you describe?
>>
>>Of course, the more complex the terms, that is in terms of their
>>relationships to other terms and permitted inferences, the
>>more complex
>>the problem would become.
>>
>>It might well be that it would end up where you are starting with the
>>
>>
>
>
>
>>merging of complete ontologies. (But just beginning at a different
>>starting point. I will have to think about that one for a while.)
>>
>>Hope you are having a great day!
>>
>>Patrick
>>
>>
>>
>>
>>
>>>Pat
>>>
>>>Patrick Cassidy
>>>CNTR-MITRE
>>>260 Industrial Way West
>>>Eatontown NJ 07724
>>>Eatontown: 732-578-6340
>>>Cell: 908-565-4053
>>>pcassidy@xxxxxxxxx
>>>
>>>
>>>
>>>
>>>
>>>
>>>>-----Original Message-----
>>>>From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
>>>>[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of
>>>>Christopher Menzel
>>>>Sent: Thursday, May 03, 2007 11:09 AM
>>>>To: [ontolog-forum]
>>>>Subject: Re: [ontolog-forum] A "common basis"
>>>>
>>>>On May 3, 2007, at 5:03 AM, Patrick Durusau wrote:
>>>>
>>>>
>>>>
>>>>
>>>>>Adam,
>>>>>
>>>>>Adam Pease wrote:
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>Hi Chris,
>>>>>> Many thanks. I was really addressing a point that you weren't
>>>>>>
>>>>>>
>
>
>
>>>>>>making, but which is all too common.
>>>>>> I'm sympathetic to using SUMO for semantic interoperability.
>>>>>>When I've done projects in that area, it has worked well. At the
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>
>>>
>>>
>>>
>>>>>>risk of stating the obvious, the advantage, at least in
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>theory, of
>>>>
>>>>
>>>>
>>>>
>>>>>>a common model over a federated approach is that one has mappings
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>
>>>
>>>
>>>
>>>>>>linear in the number of products needing integration, rather than
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>
>>>
>>>
>>>
>>>>>>potentially N^2.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>I am glad you mentioned the "potentially N^2" issue. I have seen
>>>>>that claim on a number of occassions but never with what I
>>>>>considered a convincing explanation of why it must be so.
>>>>>
>>>>>For example, assume that I have terms A, B, and C, all of which I
>>>>>
>>>>>
>
>
>
>>>>>wish to say represent the same subject.
>>>>>
>>>>>While I agree that it is possible to say A = B, A = C, B =
>>>>>
>>>>>
>>>>>
>>>>>
>>>>C, ....,
>>>>
>>>>
>>>>
>>>>
>>>>>isn't that an implementation choice?
>>>>>
>>>>>In other words, if I have the mapping A = B and then later add B =
>>>>>
>>>>>
>>>>>
>>>>>
>>>
>>>
>>>
>>>
>>>>>C, do I really need A = C? The effect of the first two mappings is
>>>>>
>>>>>
>>>>>
>>>>>
>>>
>>>
>>>
>>>
>>>>>sufficient to reach the desired result.
>>>>>
>>>>>Well, it should be noted that relying upon separate mappings does
>>>>>
>>>>>
>
>
>
>>>>>result in a problem Steve Newcomb has faced with his topic map
>>>>>implementation, that is how to determine when "all" the mappings
>>>>>have been performed.
>>>>>
>>>>>Ah, or is the N^2 claim based on a requirement that in order to
>>>>>apply whatever inferences are available at A to C, a direct
>>>>>
>>>>>
>>>>>
>>>>>
>>>>mapping
>>>>
>>>>
>>>>
>>>>
>>>>>is required? Still, that seems to be an implementation
>>>>>
>>>>>
>>>>>
>>>>>
>>>>question and
>>>>
>>>>
>>>>
>>>>
>>>>>not one of the actual mapping.
>>>>>
>>>>>That is a particular methodology of mapping is being presumed. I
>>>>>would assume once the mapping is complete, then the outcomes of
>>>>>inferencing will be the same. Yes?
>>>>>
>>>>>I have usually encountered the N^2 comment when a particular
>>>>>vocabulary is being advocated. Noting that an implied mapping is
>>>>>being peformed even by those who advocate a particular vocabulary,
>>>>>
>>>>>
>>>>>
>>>>>
>>>
>>>
>>>
>>>
>>>>>but that the implied mapping is not (usually) available for others
>>>>>
>>>>>
>>>>>
>>>>>
>>>
>>>
>>>
>>>
>>>>>to inspect or use. (The same can be the result using topic maps.
>>>>>There is no requirement that a mapping in an implementation, which
>>>>>
>>>>>
>>>>>
>>>>>
>>>
>>>
>>>
>>>
>>>>>may be commercial intellectual property, be disclosed. For
>>>>>
>>>>>
>>>>>
>>>>>
>>>>the most
>>>>
>>>>
>>>>
>>>>
>>>>>part, I think greater disclosure can potentially lead to more
>>>>>interoperability. But, there are tradeoffs and reasonable people
>>>>>will draw the line on disclosure at different places.)
>>>>>
>>>>>
>>>>>
>>>>>
>>>>I don't think this is the issue Adam had in mind, Patrick. I
>>>>believe
>>>>Adam's N^2 remark doesn't have anything to do with the terms in a
>>>>particular vocabulary (though there may in fact *be* an N^2
>>>>
>>>>
>>problem
>>
>>
>>>>of some sort lurking there), but with the number of the languages
>>>>used by the ontologies one is trying to integrate. Suppose
>>>>
>>>>
>>we have
>>
>>
>>>>four ontologies, each one written in a separate language --
>>>>say Loom,
>>>>Classic, SNEPS, and KL-1 (chosen because I have some appropriate
>>>>graphics from a presentation I gave a few years ago :-) :
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>_________________________________________________________________
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>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>--
>>Patrick Durusau
>>Patrick@xxxxxxxxxxx
>>Chair, V1 - Text Processing: Office and Publishing Systems Interface
>>Co-Editor, ISO 13250, Topic Maps -- Reference Model
>>Member, Text Encoding Initiative Board of Directors, 2003-2005
>>
>>Topic Maps: Human, not artificial, intelligence at work!
>>
>>
>>
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>>
>>
>>
>>
>
>
>
>
> (014)
--
Patrick Durusau
Patrick@xxxxxxxxxxx
Chair, V1 - Text Processing: Office and Publishing Systems Interface
Co-Editor, ISO 13250, Topic Maps -- Reference Model
Member, Text Encoding Initiative Board of Directors, 2003-2005 (015)
Topic Maps: Human, not artificial, intelligence at work! (016)
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