Over the course of our last two telecons, we've raised some issues (and
satisfied ourselves with some discussion), but we want to open these
issues up to discussion among the larger membership. (01)
1) Ontology Methodology (02)
We are going to follow steps 1-5 in the Noy & McGuinness Ontology 101
methodology. Why? Because it is relatively simple and we are trying to
adopt a KISS (Keep It Simple, Stupd) meta-methodology. The fused
Methontology-OntoClean methodology is more complicated, because it tries
to create an engineering discipline for the development of ontologies,
an ontological engineering, borrowing from the more evolved software
engineering/development lifecycle methodologies (Methontology) and from
formal ontology analysis (OntoClean). (03)
We are going to follow steps 1-5 only (and really, part of 5) because
these are generic and make no assumptions about knowledge
representation/ontology language. When you talk about "slot" and
"facet", in particular, you are oriented toward a "frame-based" KR
language, and we didn't want to force that perspective yet. [Aside:
however, when we talk about KR languages and prospective tools based on
those languages, we will possibly re-introduce these frame notions -- so
stay tuned!] (04)
Step 1. Determine the domain and scope of the ontology
Step 2. Consider reusing existing ontologies
Step 3. Enumerate important terms in the ontology
Step 4. Define the classes and the class hierarchy
Step 5. Define the properties of classes—slots
* Step 6. Define the facets of the slots
* Step 7. Create instances (05)
I'll reword the above to be the following, and probably we can adopt all
seven steps with this rewording (and I'll add a distinct step 8, even
though this step is partially included in steps 4-7, about which we'll
have more discussion later): (06)
Step 1. Determine the domain and scope of the ontology
Step 2. Consider reusing existing ontologies
Step 3. Enumerate important terms in the ontology
Step 4. Define the classes and the class hierarchy
Step 5. Define the properties of classes
Step 6. Define the additional properties related to or necessary for
properties (i.e., cardinality, bidirectionality/inverse, etc.)
Step 7. Create instances
Step 8: Create axioms/rules (07)
Question: are these revised 8 steps reasonable to folks? (08)
2) Upper Ontology/ies (09)
It is much easier to develop domain ontologies (domain defined as a
subject area or area of knowledge, e.g., business-to-business
e-commerce) when these can use upper ontologies. In our experience,
developing domain ontologies without upper ontologies causes you to
spend a good portion of your time creating what should be in an upper
ontology (if you had one), i.e., time, space, part-hood, abstract vs.
concrete, organization, process, state, task, product, location, role,
contiguity, synchronization, dependency, physical property, scalar
measures, unit of measure, etc. (010)
So it is useful at the beginning of the process in developing domain
ontologies to have and use a set of upper ontologies. SUMO (Suggested
Upper Merged Ontology) has been offered as one candidate by Adam Pease.
He has mapped one of our targeted areas of focus (Invoicing) to the SUMO
-- a very useful exercise. (011)
This is an issue we need to address: let's pull in an Upper Ontology or
set of upper ontologies, so we don't spin our wheels re-inventing stuff
that may already be available. Which ones? Well, currently there are a
few out there. SUMO, Upper Cyc, and some others probably not as
extensive. I will try to dig up a summary. (012)
Leo
--
_____________________________________________
Dr. Leo Obrst The MITRE Corporation
mailto:lobrst@xxxxxxxxx Intelligent Information Management/Exploitation
Voice: 703-883-6770 7515 Colshire Drive, M/S H305
Fax: 703-883-1379 McLean, VA 22102-7508, USA (013)
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