Monday, November 21, 2005
Center of Excellence Proposal
ŕ
ONTAC stands for Ontology and Taxonomy Coordinating Working Group
It is a working group of
Semantic Interoperability Community of Practice (SICoP)
Communication to the working group
from Paul Prueitt
****
The paper by Gangemi et al
referenced by Gary Berg-Cross approaches a type of knowledge representation
that has conceptual forms distinct from specific details. Jeff Long and Dorothy
Denning developed a notion that Jeff was enamored with and published this in
1995
Ultra-structure: a
design theory for complex systems and processes
http://portal.acm.org/citation.cfm?id=204892
Jeff and I became friends in 1996
while he was trying to start up a research center at George Washington
Univ. His work since then developed more as an internal Department of
Energy project.
From
http://bioinfo.med.unc.edu/glabwiki/index.php/CORE576:_Ultra-Structure_for_Biology
it looks like a group at Univ of
North Carolina at Chapel Hill has picked up this work.
Ultrastructure is a classification methodology that builds templates that are "deemed" to have some real and true ontological status. The interaction protocols and design abstractions (see Desai et all , Special Issue on Interaction and state-based modeling, "Interaction Protocols as Design Abstractions for Business Processes") and many many other papers have a very similar approach, but Mr Long's work perhaps predated most work specific to developing an templating classification methodology.
Ultrastructure has been available
as a conceptual architecture for over ten years, and has been used in various
domains so that there is some experience with its use. The concept of ultrastructure, in my
opinion, requires a strong separation between the detail of some specific reality
and the conceptual framework that helps communicate how that reality MIGHT be
related to other aspects of reality.
The objection, that I make -
along with others, regarding formalization need not apply if the formalization
uses a stratification of ontological representation. Let me make this
clear with a quote from Gangemi et al.
"A conceptual
architecture is required because of the main use of ontologies: making intended
meaning available to all (artificial or human) agents that could be involved in
a semantic service. Intended meaning is bound to the context in which
expressions of a language are used, such as physical situations, theoretical
frameworks, social norms, plans and goals, linguistic practices, etc. Hence,
the representation of intended meaning needs a flexible and rich set of primitives
that can be put within a modular architecture, either across ontologies or
across elements of an ontology. The intended result of this approach is
the design of ontologies which, whatever the task they are meant to accomplish,
are of a high quality, and thus able to avoid the ontology chaos that could
arise from an undervaluing of conceptual architecture."
In their next paragraph, the authors state what I feel is very important:
"Conceptual
architectures can be seen as explicit representation of context dependencies.
Such dependencies are not bound to formal languages of theories."
John, do you agree with this statement by Gangemi et al? If so, then you may also agree with my sense that ontology should be "situational" and produced by some aggregation of a subset of primitives (such as we seen in an enumeration of roles and types) into a template or conceptual form. I proposed in the anticipatory architecture that three levels of ontological organization are relevant to a specific situation;
1) a set of invariances (roles and types whose ontology is enforces by how things work in the real world),
2) the "ultrastructure" of forms, and
3) the instantiated model of reality at a moment.
The difference between the SPAN and SNAP (dynamic verse static) !!might!! be merely a question of scale of observation? Your note of today to the forum addresses this issue of scale of observation, and the nested nature of real actual (physical?) ontology:
Nicolas and Gary,
I very much like the idea of
ontology design patterns (ODP), but one point I would emphasize is that the choice
of design patterns that may be appropriate for one application may be at the
wrong level of granularity or completely inefficient for talking about and
reasoning about another level.
For example, a macroscopic
view of objects and processes has a level of granularity that may obscure
rather than clarify the entities and their interactions in computer chip design,
microbiology, or atomic physics.
Another example is the
choice of situation calculus, which is the foundation for PSL (Process
Specification Language -- a widely used ontology for representing time and
processes), but the BPM (Business Process Modeling) approach is based on the
pi-calculus, which is an orthogonal cut at representing the same kinds of entities
with a totally different set of axioms.
One of my criticisms of any
ontology that has a fixed upper level, such as DOLCE and many others (including
the one I presented in my KR book), is that there is only *one* upper
level. The DOLCE design patterns have
been designed to propagate design decisions made for the DOLCE upper level to
every level of the ontology from top to bottom.
That is a good idea *if* you
want to support a single upper level and to enforce its approach on everything at
every other level. However, that would
make it impossible to relate different perspectives with different design
patterns for different levels of granularity or different methods of reasoning.
For example, computer chip
design requires a very different level of granularity than the assembly process
of connecting parts inside a computer cabinet.
The microbiology of the processes that take place inside the liver
requires a different granularity than the operation of transplanting a
liver. But these different levels are
interconnected, and it's necessary to relate them.
In summary, I would say that
design patterns are good, but the ontologist's toolkit of patterns must have a wide
selection of patterns to accommodate different levels of granularity for
different applications.
Design patterns are highly
compatible with modularity, but you can't tie the patterns to a fixed upper
level.
John Sowa
The point that can be made with strong
stratification is the within an organizational level (defined empirically and
by the community of practice) one has both a substructure (of invariance seen
as types and roles) and an ultrastructure (seen as design pattern reflecting
real ontological forms – such as those that give interpretable meanings to
words communicated between individuals).
ŕ
additional point on formalization ŕ [228] .
I do not intend to suggest that I
know very much of anything for sure; I am just trying to bring together a
architecture where conceptual models do not have predicate logics (they as
observational (empirical) in nature and have no logic, see [228] ) The
conceptual models can “use” primitives.
These are also observed by community of practice mediation process (as
in SchemaLogic’s software system) to have no meaning unless there is a context
(much like phonemes in speech). This absence of meaning to the substructural elements (primes or
atoms) is called “double articulation” in linguistics. See [228] .
This then opens up the possibility
that predicate logic is to be attached in real time when there is a specific
model of reality (a request for a web service) that has been produced from a
fixed (but open to modification under special circumstance) set of conceptual
structures being "filled" by a subset of a set of types and
roles.
I feel that what I am proposing is not different from much of the spirit of the conversation, with the exception that I want controlled vocabularies to be the heart of interoperability and interaction protocols. These vocabularies should "evoke" a specific set of interaction protocols without the presence of a Aristotle type logical inference.
The reason is that these logical
inferences such as "is-a" appear to fail to capture all of the meaning
and intent that is possible to capture (by a human using his or her
introspection). The logical structure
may be overused and my make the task, of interaction and interoperability, far
more difficult that it should be.