Hi Patrick,
We corresponded about this a while back and it was interesting to see
how COSMO
handles these issues. Of the three top sets of partitions I was
referring to
(first/second/third order, concrete v abstract and continuant v
occurrent),
COSMO also has the concrete v abstract partition (mental object in
COSMO being
the abstract partition), and the Occurrent partition. I would also
assume that
the COSMO Context partition corresponds to the third order thing
(Mediating
Thing, or context).
On earlier ontologies I have done for clients in the financial sector,
I didn't
try to use any of these partitions. However, many of the terms which
exist in
any financial industry model (for example existing XML message
standards) are
things like Issuer, Custodian, Counterparty and so on. Parties in
particular
form a significant group of terms. These also exist in the wider
business
world, of which the financial industry is one sub set. For example
contracts
have parties and these are specialised to Issuer and Holder of a
security (or
for an over the counter swap security, they are both simply
counterparties, as
in any bilateral contract). Similarly transactions, which form part of
the
definition of an over the counter derivative, exist in the wider world.
Looking at the COSMO model again, it seems that you have solved the
exact same
problem I am describing. The class of Role, which is a sub-class of
Temporal
Thing, contains a wide range second order things, including the
sub-class Human
Role containing those things like Parent and Spouse which are second
order
things. Meanwhile Human Role is also a child of Person, so that the
second
order thing inherits the properties of the first order thing that it
is.
So you have solved the exact same problem I am talking about, but in a
different way. Where I have an object property identifying the first
order
thing, you have a parent relationship to achieve the same effect.
There are a few aspects of the COSMO ontology which I find
counter-intuitive on
this, for example PersonWithOccupation and SkilledOccupation are shown
as
peers, both being sub-classes of HumanRole, and I would have thought
that one
of these was a specialisation of person while the other was a
specialisation of
role.
I am not sure how you would deal with situations where for example a
client or
a counterparty may be either a human being or a company. Here I have
legal
entity as the common first order class, which (when required for a
specific
defition) can be specialised to be a company, a country or a human
being etc.
For example almost any legal entity may be an issuer, but the issuer of
a
corporate bond may only be a company. Government bonds present an
interesting
challenge because they are issued by a government, which is a second
order
thing, on behalf of the country (legal entity) they govern.
There is an interesting modelling choice around roles and second order
things,
because in principle one could model roles as OWL Object Properties (as
I do)
but then one could simply make the range of that property a first order
thing.
Here I think the choice has to depend on how any data derived from the
ontology
is to be used. As long as there are likely to be qualifying terms for a
role
(as there may be financial definitions), it makes sense to model it as
an OWL
Class, and therefore it needs to be a second order thing, like your
Role
classes. Otherwise you would have to be able to apply datatype
properties and
object properties to an object property. So the separation of role and
second
order thing sometimes results in apparently tautologous terms and these
would
often need to be collapsed in any logical data model derived from the
ontology.
In terms of the usefulness of these, I think it solves a number of data
problems that people have been seeing in the financial industry, where
people
have tried to manage semantics from within a data model or message
schema, and
for example where mapping between two such data schemes proves
difficult. So
for example some securities issuance terms would have "Underwriter"
with a list of phone numbers, "Syndicate member" with another such
list, and so on. Obviously these would be combined in any logical data
model,
but it makes sense to define "Legal Entity" with all of the phone
numbers and things, and then terms specific to the process (such as
contact
person for that process, with their phone number) would be in the
second order
thing, rather than all of these terms being mixed in together.
Similarly I have
spoken to people who are struggling with client and counterparty
definitions as
a result of conflating client with legal entity - a valid conflation
within a
single computer system but a problem when you want to define terms
globally
across a business unit. Having the second order thing with the object
property
of "identified as" linking to a legal entity resolves this and allows
for mapping between data sources that have different treatments of
these, via
the common semantics model.
I guess the bigger picture is that all computer systems have an
ontology
already whether it's documented or not, and we are trying to establish
a common
ontology to be used across a business unit, a company or an industry,
and
therefore the different shades of meaning that are irrelevant within
one
program become important if one is to link them together or re-use data
intelligently within different applications.
For the ontology I am working on, my client's main aim is to
accommodate all
the terms that exist in different systems and message standards, within
a
single consistent framework. This replaces the various ad hoc business
spreadsheets that are used in many firms today, and brings the
semantics out of
the technical models, where the business knowledge is often lost or
undocumented. Potentially this can be used to derive logical data
models, as
the ad hoc spreadsheets would have been.
This means that usability is a major requirement for this model. But
not
usability as an ontology per se. Rather, this is an attempt to show
business
stakeholders a view of their world, which they can validate. As such, I
have
found that the first / second order distinction can be easily explained
to
business users, since it is not a technology definition they are being
asked to
learn, but rather a real world distinction. A few examples usually put
the
point across fairly easily, and they are then able to contribute to the
definition of data items and relationships without needing to
understand database
modelling. Having said that, most business participants will rarely
need to
look at the top level of the model, except where there is an argument
about
different meanings applying to a similar word or term. Then the model
structure
serves to unambiguously identify the intended meaning of something.
I do not envisage a scenario where any of the users of this model are
likely to
fire up Protege and search for something in that. They will either
navigate the
diagrams or search for things in the spreadsheet view. However, once
enough
people ask for it I hope to get a budget to convert the content into an
OWL or
RDF file format so that other, more advanced things like automated
reasoning
and semantic queries can be done with it. I would like to see that.
Even then,
the primary business interface would be tables/spreadsheets and
technology-neutral diagrams, as business sign-off is a vital component
of
getting the terms complete and correct. I am watching with interest
those tools
that are starting to evolve a business-readable interface.
Incidentally I thought the presentation by Mike Bergman on the UMBEL
(Upper
Mapping and Binding Exchange Layer) at our recent showcase
teleconference was
very interesting. UMBEL provides a means to relate upper ontologies to
each
other. It will be interesting to see how this deals with issues like a
role
being an object property in one ontology and a class in another, and
how it
would help to relate second order classes from ontologies which have
defined
these differently, or which have different and potentially conflicting
parent
classes. Because it seems to me that the second order things are all
there in
these upper ontologies, whether they are identified as such or not.
Best regards,
Mike
Patrick Cassidy wrote:
Mike -
Concerning your question:
MB> It also made sense to me, to distinguish between first- second-
and third-order classes of Thing, as defined by John Sowa and
others (John's book summarises the history of those terms very well).
MB> What interests me, and what I am really asking here, is why is
this approach not noticeable in upper ontology resources like
the Suggest Upper Merged Ontology (SUMO)? Am I missing something?
SUMO looked to me like a single taxonomic hierarchy of classes
of Thing, without these three sets of partitions.
I can't answer for SUMO, but I can tell you why those distinctions don’t
appear in COSMO:
*** there is no apparent need for them, and spending time trying to
decide into which of those abstract categories one might place specific
types or relations does not make any sense to me, as they add nothing to the
intended meaning. ***
Wherever one might think that a type or relation fits one of those
categories, the more specific and meaningful type or relation itself will
carry all the meaning required to perform the intended function of the
ontology.
The top level of COSMO under 'Thing' has 20 types, and one of the those
('Individual') is a heterogeneous grouping of other types that are mostly
heterogeneous groupings associated by some property (a 'faceted'
categorization). If I had 'firstness' secondness' and 'thirdness' at the
top level, I expect that few people wanting to find some particular type of
thing would have no idea where to start in the drill-down process. Tools
like Protégé that allow searching for substrings in the label for a type
help immensely, but as far as creating a hierarchy for drill-down when
string search fails, those three abstract categories, in my estimation, are
quite useless. I am very concerned with usability of any ontology, meaning
that it has to be as easy as possible to understand, while preserving its
technical adequacy.
Those abstract categories may be interesting for philosophical
speculation, but I have never observed any function for them in automated
reasoning. More specific issues dominate my concerns about representing
meaning.
If they help you organize your own thinking about the meanings of
concepts, they may be useful, for you, for that purpose. I haven't found
them useful in that way.
However, if anyone were interested in trying to figure out which of those
categories applies to the elements of the COSMO ontology:
http://www.micra.com/COSMO/
I would have no objection. If some useful function could be demonstrated by
the act of such a classification, I would be intrigued and may change my
mind about their usefulness.
Pat
Patrick Cassidy
MICRA, Inc.
908-561-3416
cell: 908-565-4053
cassidy@xxxxxxxxx
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Mike Bennett
Director
Hypercube Ltd.
89 Worship Street
London EC2A 2BF
Tel: 020 7917 9522
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