Re: SUO: Conformance and Interoperability: 3-D vs. 4-D
Chris Partridge wrote:
> In a 3-D ontology there are two things; you (a continuant) and your
> life (an occurrent), in a 4-D ontology there is only you. In your
> 'single ontology' do you envision there to be three things with
> apparatus for translating statements about the 3-D objects to
> statements about the 4-D objects - and vice versa?
Yes, that is what I hope would be possible. If so, then if
one wants to use only 3-D or only 4-D objects, then a translation
could be performed with subsequent reasoning within one's preferred
paradigm. Perhaps there will be some things easier said in 3-D and
some in 4-D, and some ontologists may decide to use both.
> This would of course lead to duplication of predicates a 3-D
> fluent/temporalised 'weighs 10lb' would need to have an 4-D eternal
> untemporalised 'weighs 10lb'. This would lead to a sort of apartheid,
> with 3-D objects and predicates on one side, and 4-D ones on the
> other. Is this the sort of thing you envisage?
That may be necessary, but wherever there are accurate translations
of one representation to another, there may be some cases where
predicates can be shared.
For example, in either 3-D or 4-D one might want to have an
atemporal predicate "isFatherOf" which could serve for both 3-D and
4-D objects:
(isFatherOf ?FATHER ?CHILD)
In either representation there would be an axiom on such a predicate
stating that for each instance of such a predicate, there is a birth
event of (hopefully) short duration in which the ?FATHER is of
child-bearing age and the ?CHILD has age 0 at the time of that
event, and ?FATHER has contributed one-half of the genes of the ?CHILD.
In both cases, this would also imply the age restrictions on ?FATHER
and ?CHILD such that the birth date of ?FATHER is, say, 9 to 120 years
earlier than that of ?CHILD. It would also imply that the predicate
itself could not be asserted unless the birth event has already
occurred at the time of the assertion. This is a type of
meta-restriction on the use of predicates that may be necessary,
but I haven't seen discussed.
The translation of "weighs 10lb.", if it were true throughout the
lifetime of the object, might also use a single atemporal predicate on
a 3-D or 4-D object, in either case implying that the weight is the same
at every time point of its existence the 3-D object and for all temporal
parts of the 4-D object.
I think that part of the problem in deciding how to translate 3-D
to 4-D predicates is in the common use of atemporal predicates without
any explicit axiomatization of how the predicate relates to specific
points or intervals of time. For example, one might write:
(hasPart Automobile Motor)
in either 3-D or 4-D. I don't know what that means in 4-D. In 3-D
there are at least 3 possible interpretations:
(1) An automobile always has a motor. Therefore, as long as an
automobile exists it has a motor. If the motor is removed, it is
not an automobile.
(2) An automobile always has a motor. If the motor is removed,
it is still part of the automobile, but the automobile is in the
"disassembled" state.
(3) An automobile has a "role" for a motor to fill, but it may still
be an automobile even if there is no instance of a motor that fills
that role.
In the second case, we have to decide whether, once all the parts
of an automobile are ready for assembly, does the automobile exist
from that point? Or is some assembly necessary before the
automobile begins it existence?
Note that the time restrictions are asymmetrical. In any of these
cases, a motor may exist without any corresponding automobile for
it to be part of.
It think that only after we have agreed on the detailed
axiomatizations of related predicates for 3-D and 4-D objects,
will we be able to decide whether a translation is possible.
I suspect, without any evidence, that it is the common use of
atemporal predicates on 3-D objects without detailed axiomatization
of the implications for time points that may make the 4-D view
seem more natural to some thinkers.
My preference is to use atemporal predicates for physical
3-D objects as rarely as possible, instead always including
some explicit time interval for which the predicate holds.
The time interval in relations between objects can be for
the lifetime of one of the objects.
I suspect that the translation between 3-D and 4-D predicates would
be peculiar for each predicate, but there may be some regularities that
lighten the task. As I mentioned, I am still very unclear as to
the meaning of predicates on 4-D objects, especially those between
4-D objects, as to how they relate to the temporal parts of those
4-D objects. So I don't have any suggestions as to translation
at this point.
Pat Cassidy
========================
Chris Partridge wrote:
> Pat,
>
> You asked:
> "The question of 3-D versus 4-D objects has also
> been discussed, but I am still uncertain in that case that
> there is no way to express 4-D concepts with 3-D concepts that
> include time intervals explicitly in the assertions; in such
> a case they should be able to coexist in a single ontology
> without contradiction. I would very much like to see examples
> that cannot be translated between the two representations."
>
> In a 3-D ontology there are two things; you (a continuant) and your life (an
> occurrent), in a 4-D ontology there is only you. In your 'single ontology'
> do you envision there to be three things with apparatus for translating
> statements about the 3-D objects to statements about the 4-D objects - and
> vice versa? This would of course lead to duplication of predicates a 3-D
> fluent/temporalised 'weighs 10lb' would need to have an 4-D eternal
> untemporalised 'weighs 10lb'. This would lead to a sort of apartheid, with
> 3-D objects and predicates on one side, and 4-D ones on the other. Is this
> the sort of thing you envisage?
>
> Regards,
> Chris
>
> -----Original Message-----
> From: owner-standard-upper-ontology@majordomo.ieee.org
> [mailto:owner-standard-upper-ontology@majordomo.ieee.org]On Behalf Of
> Patrick Cassidy
> Sent: 26 October 2001 19:42
> To: West, Matthew R SITI-ITPSIE
> Cc: Standard-Upper-Ontology (E-mail)
> Subject: Re: SUO: Conformance and Interoperability
>
>
>
> Matthew West has questioned the possibility of interoperability
> using a common Upper Ontology:
>
> [MW]
> >
> > In my view, there is only a benefit if using the SUO
> > provides interoperability between the different ontologies
> > that use the SUO as their core. So let us look at the
> > degree of interoperability that can be guaranteed between
> > such ontologies.
> >
> . . .
> >
> > Bottom line: The use of a common upper ontology guarantees
> > nothing about different lower ontologies. Therefore having
> > a conformance statement that suggests otherwise is
> > misleading.
> >
>
> My understanding of the best case of interoperability is
> when two different systems presented with the same data
> derive the same inferences. The requirements I envision for
> enabling such an outcome are either:
>
> (1) both systems use exactly the same ontology and inferencing
> mechanisms.
>
> or . . .
>
> (2) both systems use the classes and relations of a standard
> upper ontology to define any new classes and relations,
> with all local extensions compatible with the Standard in
> not generating any contradictions. When interchange of
> data is desired, each system must transmit to the other
> system any newly defined classes and relations as well
> as specifying known instances of those new classes,
> and also transmit any new inferencing mechanisms not
> used by the other system. If the combined system with
> both sets of extensions cause contradictions to be
> generated, then some measures must be taken to eliminate
> the contradictions by changing one or both extensions.
>
> Method 2 answers Matthew's question:
> >
> > The question revolves around whether there is any benefit
> > in having ontologies that use the SUO as its core but with
> > local extensions being able to claim conformance for the
> > whole ontology, rather than just their use of the SUO.
> >
>
> Yes, if two ontologies do define their extensions using a
> common upper ontology there is a process available to achieve
> complete interoperability, but if they use different upper
> ontologies, no such process is available. The corollary is
> that, the smaller the extensions are as a fraction of
> the total ontology, the easier it will be to achieve true
> interoperability by the above process. There may
> be methods to map one ontology to another, but that will
> not achieve the level of interoperability achievable by use of
> a common upper ontology with such a reconciliation process.
>
> As has been pointed out previously, any one set of upper
> concepts can be used to derive different sets of new concepts
> that have properties differing from each other. True
> interoperability can only be achieved if those developing
> their own extensions are willing to share them with others
> with whom they want their systems to interoperate. A lesser
> degree of interoperability may still be achieved if extensions
> are not shared or prove contradictory, but this should
> surprise no one, and it seems to be the kind of case
> that Matthew has described. What is unclear from
> Matthew's note is whether he thinks that some form of
> mapping between incompatible domain ontologies that do
> *not* use the same upper ontology will be just as easy as
> a mapping between two domain ontologies that *do* use a common
> upper ontology. I would expect that mapping, where necessary,
> will be easier, even between contradictory ontologies,
> when a common upper ontology is used. Is there any experience
> to suggest otherwise?
>
> The ease of developing contradictory extensions is
> precisely the problem that has led me to argue on several
> occasions that, although we are concerned first with
> developing a Standard **Upper** Ontology, the definition
> of more specialized concepts that could be included in
> optional modular extensions should not be discouraged.
> It serves two useful purposes -- to make the intended
> meanings of the higher categories more precise (by reducing
> ambiguity about the instances that fall under each class);
> and to provide common off-the shelf modules for those for
> whom they are adequate, reducing the chances that
> contradictory extensions will be developed by those
> who desire interoperability. The cutoff point for the
> "Upper" and the start of the "extensions" can be
> debated after some stability and agreement on the
> highest levels of the upper-most ontology have been
> achieved.
>
> What is still not known, and is a major question that
> development of a Standard Upper Ontology can help to answer,
> is in how many cases the different and contradictory treatments
> of the same concept in different ontologies have arisen simply
> because there was no widely-used standard ontology, rather than
> because their users felt that the different concept definitions
> were **absolutey necessary** to achieve the performance they
> desired. Pat Hayes has given examples of contradictory time
> theories. The question of 3-D versus 4-D objects has also
> been discussed, but I am still uncertain in that case that
> there is no way to express 4-D concepts with 3-D concepts that
> include time intervals explicitly in the assertions; in such
> a case they should be able to coexist in a single ontology
> without contradiction. I would very much like to see examples
> that cannot be translated between the two representations.
> Still, there is a widely-held opinion that *some* contradictory
> theories will be needed to satisfy the requirements of different
> users, and there is a corresponding widely-held opinion (I think)
> that the SUO should make some provision for including alternate
> theories (and also possible worlds and fictional contexts).
> The best form for this "lattice" of theories should, I think,
> be a major thread in these discussions. My feeling is
> that in order to claim to be a "standard" upper ontology,
> every effort should be made even in the case of alternate
> incompatible theories to minimize the differences, by reducing
> them to the absolute minimum that different users insist
> cannot be reconciled. This should maximize interoperability
> between incompatible theories, which may then have to rely
> on some form of mapping to bridge the residual differences.
>
> In addition to Adam's requirements for "conformity", I
> would add that every leaf node of the SUO should have
> at least one and preferably multiple instances defined,
> and every conforming ontology must have those instances
> retained as instances of the original classes, though they
> may be distributed among newly-defined subclasses. This
> will reduce the chances of contradictions in ontologies
> using the SUO with different extensions.
>
> Pat Cassidy
>
>
> =============================================
> Patrick Cassidy
>
> MICRA, Inc. || (908) 561-3416
> 735 Belvidere Ave. || (908) 668-5252 (if no answer)
> Plainfield, NJ 07062-2054 || (908) 668-5904 (fax)
>
> internet: cassidy@micra.com
> =============================================
>
>
>
>
> West, Matthew R SITI-ITPSIE wrote:
>
>
>>Dear Colleagues,
>>
>>I have been arguing for a very narrow conformance statement
>>whilst Adam has been arguing for something more wide
>>ranging. In this note I will try to explain why a more
>>wide ranging conformance statement achieves almost
>>nothing and is potentially misleading.
>>
>>The question revolves around whether there is any benefit
>>in having ontologies that use the SUO as its core but with
>>local extensions being able to claim conformance for the
>>whole ontology, rather than just their use of the SUO.
>>
>>In my view, there is only a benefit if using the SUO
>>provides interoperability between the different ontologies
>>that use the SUO as their core. So let us look at the
>>degree of interoperability that can be guaranteed between
>>such ontologies.
>>
>>One thing I hope we would agree on by now is that it is
>>possible to have different conceptions of the world. At
>>the level we are at we have already found that there can
>>be a 3D or a 4D view. If the SUO stopped at Chris Menzel's
>>set theory, it would be perfectly possible for two groups
>>to work independently, one on a 4D ontology, one on a 3D
>>ontology. There would essentially be no interoperability
>>between these two ontologies, except where the set theory
>>concepts defined in the common module were used. In fact
>>even this would be minimal, because almost the first act
>>of developing a 4D ontology would be to create a concept
>>of a set with unchanging membership, which would then
>>be the primary concept of set/class used in the rest
>>of the ontology.
>>
>>On the other hand, these two ontologies can be integrated
>>by creating a mapping between them that says things like
>>if I have a continuant then I also have a 4D object of a
>>certain type, etc. I can then interoperate between 3D and
>>4D conceptions.
>>
>>Well this is a dramatic example, but in fact the chances
>>of any two groups independently developing an ontology
>>that is identical where it overlaps - even in the axioms
>>- let alone the labels is sufficiently remote as to be
>>fanciful.
>>
>>Bottom line: The use of a common upper ontology guarantees
>>nothing about different lower ontologies. Therefore having
>>a conformance statement that suggests otherwise is
>>misleading.
>>
>>
>>You will gather that I feel quite strongly about this,
>>and this is not without reason. I have been working in
>>ISO TC184/SC4 now for some 8 years. One of the standards
>>being developed there is ISO10303 - Standard for the
>>exchange of product model data. This was developed
>>(starting in the late '80s) precisely on a core that
>>was incorporated into different models that included
>>extensions for specific requirements. Many of the
>>developers of these standards expected that they
>>would be interoperable because they had a common core.
>>They were disappointed. The only parts that ended up
>>interoperable were those that were harmonised as part of
>>the development.
>>
>>This caused sufficient concern that in 1995 SC4 set up
>>a new Working Group, WG10, with one of its principle
>>tasks being to investigate why interoperability was
>>not achieved and what it takes to ensure interoperability.
>>
>>I am the Deputy Convenor of WG10, and I have lead this
>>work strand. The results are incorporated in ISO18876.
>>http://www.iso18876.org/
>>
>>A definition of lunacy: executing the same process twice
>>and expecting a different outcome.
>>
>>
>>Matthew West
>>Principal Consultant
>>Shell Information Technology International Limited
>>Shell Centre, London SE1 7NA, United Kingdom
>>
>>Tel: +44 20 7934 4490 Other Tel: +44 7796 336538
>>Email: matthew.r.west@is.shell.com
>>Internet: http://www.shell.com
>>http://www.matthew-west.org.uk/
>>
>>
>>
>
>
>
--
=============================================
Patrick Cassidy
MICRA, Inc. || (908) 561-3416
735 Belvidere Ave. || (908) 668-5252 (if no answer)
Plainfield, NJ 07062-2054 || (908) 668-5904 (fax)
internet: cassidy@micra.com
=============================================