Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Ontology Overview Introduction Motivation Ontologies compared to other stuff Upper ontology specifics Adam Pease Articulate Software - SUMO on line - Sigma environment - publications, references

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Definitions An ontology is a shared conceptualization of a domain An ontology is a set of definitions in a formal language for terms describing the world

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Motivation select EMPDAT from PERSTAB where POS=“mgmnt” – What does it mean? – PERSTAB is a table which lists employee data » What’s an employee? How is an employee different from a contractor? What if I want data on both? Even if this information is available in natural language, a human has to read it

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Motivation (2) "Parenthood is a more general relationship than motherhood." "Mary is the mother of Bill." "Who are Bill's parents?“ "Mary is the parent of Bill.” – that fact is not stated anywhere, but can be derived by a DAML application. Example from “Why Use DAML?”

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Motivation (2) continued More formally stated, given the statements (motherOf subProperty parentOf) (Mary motherOf Bill) when stated in DAML, allows you to conclude (Mary parentOf Bill) Java code or a stored procedure could do this sort of inference for facts in XML or SQL But the DAML spec itself says the conclusion is true In contrast, different Java code could reach a different conclusion

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Motivation (2) continued (Mary motherOf Bill) (parentOf inverse childOf) (Bill childOf ?X) ?X = Mary The semantics of inverse is part of the DAML spec

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Language Formality and Expressiveness Formality Expressiveness Human Language KIF CycL OWL F-Logic DAML XML SQL Human Consumption Machine Processing Machine Inference

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Frames Object- or term-centered Frames, slots, values, (and attributes) Adam: Person height occupation 5'8” consultant cardinality: 1

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Frame Restrictions b is between a and c – (between1 a betweenness1) – (between2 b betweenness1) – (between3 c betweenness1) – vs – (between a b c) Adam is not an accountant – (notOccupation Adam Accountant) – vs – (not (occupation Adam Accountant)) Existential vs. Universal quantification Similar problems for many description logics Very efficient computation however

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Content Formality and Size Formality WordNet Cyc SUMO DOLCE LexiconsFormal Ontology Taxonomy Size SUMO+domain UMLS Yahoo!

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Many Ways to Use Ontology As an information engineering tool – Create a database schema – Map the schema to an upper ontology – Use the ontology as a set of reminders for additional information that should be included As more formal comments – Define an ontology that is used to create a DB or OO system – Use a theorem prover at design time to check for inconsistencies For taxonomic reasoning – Do limited run-time inference in Prolog, a description logic, or even Java For first order logical inference – Full-blown use of all the axioms at run time

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Upper Ontology An attempt to capture the most general and reusable terms and definitions

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Motivation Ontologies may have different names for the same things – type – a relation between a class and an instance – instance – a relation between a class and an instance – isa – a relation between a class and an instance – … Ontologies may have the same name for different things, and no corresponding terms – before – a relation between two time points – before – a relation between two time intervals Either use the same upper ontology, or at least map to a common upper ontology

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Formal Upper Ontologies DOLCE Cyc SUMO

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Suggested Upper Merged Ontology ● 1000 terms, 4000 axioms, 750 rules ● Mapped by hand to all of WordNet 1.6 ● A “starter document” in the IEEE SUO group ● Associated domain ontologies totalling 20,000 terms and 60,000 axioms ● Free – SUMO is owned by IEEE but basically public domain – Domain ontologies are released under GNU

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered WordNet ● Lexical database ● 100,000 word senses – synsets ● Free ● De facto standard in the linguistics world

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered SUMO ● In use by academics and industry ● Versions available in KIF, XML, DAML, LOOM, Protege ● Language generation templates in English, Czech, Italian, German, Hindi, Chinese ● Open source browser

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered SUMO Structure Structural Ontology Base Ontology Set/Class TheoryNumericTemporalMereotopology GraphMeasureProcessesObjects Qualities

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered SUMO+Domain Ontology Structural Ontology Base Ontology Set/Class Theory NumericTemporalMereotopology GraphMeasureProcessesObjects Qualities SUMO Mid-Level Military Geography Elements Terrorist Attack Types Communications People Transnational Issues Financial Ontology Terrorist Economy NAICS Terrorist Attacks … France Afghanistan UnitedStates Distributed Computing Biological Viruses WMD ECommerce Services Government Transportation World Airports Total Terms Total Axioms Total Rules

Copy right 2004 Adam Pease permission to copy granted so long as slides and this notice are not altered Conclusion Reuse is important – don't reinvent the wheel Open source lowers costs (especially for early- stage technology) Focus on content reuse, not just language reuse Expressiveness is your friend