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gist: a minimalist upper ontology. Dave McComb Semantic Arts Semantic Technology Conference June 1x, 2009. Premises. Basing your ontology on an upper ontology can increase your productivity and the quality of the resulting ontology
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gist: a minimalist upper ontology Dave McComb Semantic Arts Semantic Technology Conference June 1x, 2009
Premises • Basing your ontology on an upper ontology can increase your productivity and the quality of the resulting ontology • Basing your ontology on an upper ontology will make interoperation with others using that upper ontology much easier • Not all upper ontologies are alike
Agenda • Modular and layered ontologies: how and why • Facets: breadth, depth, understandability • Understanding gist • Experience report • What’s next
Modular and layered ontologies: how and why • Ontologies can get • Large, and • Complex • This has three downsides • Inference slows down • There is more for the humans to understand • There may be stuff in there you don’t agree with
Commit • When you “import” an ontology it’s not like a library of subroutines where you only use what you want • You get it all, • and all the implications • Hence the term “committing” to an ontology
Commitment is directional • A “commits” to B does not imply that B “commits” (or even knows about) A A B
Mutual Commitment • Two ontologies that commit to a third common ontology have some basis for exchanging information • It’s limited to the scope of their use of the shared ontology • But at least it’s something
Sharing is limited to.. ...the amount you share
Contention: The smaller your shared ontology + number of things based on the shared ontology, the more scope for sharing
Facets: breadth, depth, understandability • What would you want in an upper ontology? • Our contention is that you would • 1) want it to cover most of the concepts you have in your domain • 2) with minimal ambiguity or overlap • 3) easy to understand
A few examples • foaf • dublin core • skos • Cyc • sumo
foaf (friend of a friend) Concepts typically expressed in a business system foaf Mostly people and their relationships
Dublin Core Concepts typically expressed in a business system dc Documents, authors, publishers, rights
SKOS Concepts typically expressed in a business system skos essentially a thesauruss
cyc cyc Concepts typically expressed in a business system hundreds of thousands of common sense terms axiomized
sumo sumo Concepts typically expressed in a business system tens of thousands of terms tied to word net and axiomized
Upper Ontologies cyc sumo gist xbrl ebXML Breadth dc foaf skos Ease of understanding
Understanding gist • gist has • xx properties • xx primitive classes • xx partially defined classes • xx fully defined classes
You already agree on many of the concepts • Person (human being, living or dead) • Substance (occupies space and has mass) • Location (geospatial) • Time (specific dates and times in the past and future and intervals of time)
There are some that we just have to agree on, or there is no commerce • Organization • Units of measure, including currency • Ownership and rights • Documents and content • Recorded events, including transactions • Agreements, contracts, obligations and offers
And some properties • Superior/Subordinate (Whole/part, contains/contained) • Reference (about, regarding) • Datatype attributes (name, amount, date, time, text) • Features (non simple attributes) (start/end dates, ids,
Key types (also by color) Time Place Person Thing Stuff Doc Behavior Agree Goal Category
A couple of other “too concrete to model” but worth including... Now Here Home Me
Back to time Measurement Type (ie Measured, Estimated, Predicted or Reference) Measurement (the act of taking the measure) Unit of Measure second Duration unit of measure (week, month, second ) etc Duration (one week) Time Interval (i.e. 12/25/2008- 1/1/2009) Time Instant (i.e. Sept 11, 2001)
Non obvious key concepts: Agreement, obligation, offer • Almost all of business is about the management of commitments or obligations (quotes, purchase orders, price lists, invoices, even checks are obligations) • Obligation is the key concept: • There are two parties (if you only have one party and rules about who can be the second party you have an offer) • There is the substance of the obligation (to do, or refrain from doing something, including pay or provide service) • Substance is described in “term”(s) • One party is the giver and one the getter of this obligation
Agreements • An agreement (i.e. a contract) is a bundle of obligations between two or more parties (givers and getters) • The simplest agreement has two obligations: • an obligation for giver (A) to provide a product or service to getter (B) and • an obligation for giver (B) to pay getter (A) • Note that this says nothing about the timing (pay first, pay later etc)
Patterns • Highly axiomized • Units of Measure defined by their standard unit • Logically fewest datatype properties • Heavy use of subproperties
OWL 2 • Qualified Cardinality (more for sub ontologies) • Disjoint properties • Property chains
OWL 2 Qualified Cardinality • Borrow simons slide
Disjoint Properties • giver and getter
Property Chains (bridging 3D and 4D) • Ownership and Location
Experience Reports • Two major Enterprise Ontologies based on gist • Washington State Employment Security Division • A large (modest) loan company • Using gist greatly sped up the ontology capture process • Most concepts had either an identical or more general class in gist, which avoided a lot of negotiation • Very high coverage of both properties and classes • Most of the concepts in the EOs were decedents of gist concepts
gist • current version http://ontologies.semanticarts.com/gist/gist.owl • archived versions http://ontologies.semanticarts.com/gist/gist2009May20.owl • documentation (including this presentation) http://www.semanticarts.com/gist/doc***
