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Foundations IV: Ontology Evolution and Knowledge

ManagementClass Session 6

Deborah McGuinness and Peter Fox (NCAR)

CSCI-6962-01

Week 6 – October 6, 2008

Review• Ontology Evolution Environment (Chimaera)

Reading

• Assignment

• Any comments, questions?

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Semantic Web Methodology and Technology Development Process

• Establish and improve a well-defined methodology vision for Semantic Technology based application development

• Leverage controlled vocabularies, et c.

Use Case

Small Team, mixed skills

Analysis

Adopt Technology Approach

Leverage Technology

Infrastructure

Rapid Prototype

Open World: Evolve, Iterate,

Redesign, Redeploy

Use Tools

Science/Expert Review & Iteration

Develop model/

ontology

Some Current Motivating Trends

• More applications are depending on background ontologies for : Site Organization, Query expansion, Integrity checking, …

• Systems are increasingly hybrid… thus requiring integration with many other systems

• There are an increasing number of existing vocabularies / taxonomies / ontologies that are official or defacto standards

• Applications are becoming more long lived, thus requiring evolution and maintenance

• …

Approach for today• Introduce one early ontology evolution

environment from 2000 (including historical motivation and capabilities)

• Discuss its strengths and weaknesses

• Followed by group discussion of where this area is evolving and should evolve today

Motivation: Ontology Integration Trends

• Integrated in most search applications– General search from 2000: Yahoo, Lycos,

Xift, …)– General search today: Yahoo, keyword

advertising and more– Scientific search today: e.g. Noesis

• Core component of E-Commerce apps (Amazon, eBay, Virtual Vineyards, REI, etc.)

• Integrated in configuration applications (Dell, PROSE, …. Sun, SAP, Trilogy, …)

Motivation: Ontology Evolution• Controlled vocabularies abound (SIC-codes,

UN/SPSC, RosettaNet, OpenDirectory,…)• Distributed ownership/maintenance• Larger scale

– (Open Directory >23.5K editors, ~250K categories, 1.65M sites – true in 2000)

– (Open Directory (now arguably less mainstream has over 81K editors, and 590K directories, and >4.6M sites)

• Becoming more complicated - Moving to classes and slots (and value restrictions, enumerated sets, cardinality)

Motivation: Science Ontologies Today• Growing awareness and consensus on

science taxonomies/ontologies (SWEET, ChemML, …)

• Growing interest in community ownership/maintenance

• Editors are less typically trained in computer science…. thus tools need to be aimed at broader audiences

• Domain ontologies are growing more complicated – GO, BioPortal, …

• Domain specific environments are starting to emerge

Chimaera – A Merging and Diagnostic Ontology Environment

Web-based tool utilizing the KSL Ontolingua platform that supports:

• merging multiple ontologies found in distributed environments

• analysis of single or multiple ontologies• attention focus in problematic areas• simple browsing and mixed initiative editing

Historical Setting• Large government sponsored project • Broad ontology needs – CIA World Fact

Book, terrorist information, biological and chemical knowledge, weapon knowledge, …

• Number of ontologies approaching 100• Large sets of facts – mined from natural

language text• Complicated question set• Distributed work force (many without much

training in computer science)• Time pressure

Historical KB Analysis Task• Review KBs that:

– Were developed using differing standards

– May be syntactically but not semantically validated

– May use differing modeling representations

– May have different purposes

• Produce KB logs (in interactive environments)

– Identify provable problems

– Suggest possible problems in style and/or modeling

– Are extensible by being user programmable

• End user humans (but not with extensive training)

The (General) Need For KB Analysis

• Large-scale knowledge repositories will necessarily contain KBs produced by multiple authors in multiple settings

• KBs for applications will typically be built by assembling and extending multiple modular KBs from repositories that may not be consistent

• KBs developed by multiple authors will frequently– Express overlapping knowledge in different, possibly contradictory ways

– Use differing assumptions and styles

• For such KBs to be used as building blocks -They must be reviewed for appropriateness and “correctness”

• That is, they must be analyzed

Historical KB Merging Needs

• One large reasoning task using many large scale KBs

• KBs for applications were required to extend existing ontologies (CYC and others)

• Overlapping ontologies and instance data

• For such KBs to be used together as building blocks -

Their representational differences must be reconciled

The KB Merging Task• Combine KBs that:

– Were developed independently (by multiple authors)

– Express overlapping knowledge in a common domain

– Use differing representations and vocabularies

• Produce merged KB with

– Non-redundant

– Coherent

– Unified vocabulary, content, and representation

How KB Merging Tools Can Help– Combine input KBs with name clashes

• Treat each input KB as a separate name space

– Support merging of classes and relations• Replace all occurrences by the merged class or relation• Test for logical consistency of merge (e.g. instances/subclasses of multiple

disjoint classes)• Actively look for inconsistent extensions

– Match vocabulary• Find name clashes, subsumed names, synonyms, ...

– Focus attention• Portions of KB where new relationships are likely to be needed

E.g., sibling subclasses from multiple input KBs

– Derive relationships among classes and relations• Disjointness, equivalence, subsumption, inconsistency, ...

Merging Tools• Merging can be arbitrarily difficult

– KBs can differ in basic representational design

– May require extensive negotiation among authors

• Tools can significantly accelerate major steps

• KB merging using conventional editing tools is– Difficult Labor intensive Error prone

• Hypothesis: tools specifically designed to support KB merging can significantly– Speed up the merging process

– Make broader user set productive

– Improve the quality of the resulting KB

Experiment 3: Chimæra vs. Ontolingua editor

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0 400 800 1200 1600 2000 2400 2800 3200 3600

Time (s)

Cum

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pera

tions Chimæra

Ontolingua Editor

Chimaera Usage

• HPKB program – analyze diverse KBs, support KR novices as well as experts

• Cleaning semi-automatically generated KBs• Browsing and merging multiple controlled

vocabularies (e.g., internal vocabularies and UN/SPSC (std products and services codes))

• Reviewing internal vocabularies

Discussion in its time• Ontologies are becoming more central to applications, they Ontologies are becoming more central to applications, they

are larger, more distributed, and longer-livedare larger, more distributed, and longer-lived• Environmental support (in particular merging and diagnostic Environmental support (in particular merging and diagnostic

support) is more critical for the broader user basesupport) is more critical for the broader user base

• Chimaera provides merging and diagnostic support for Chimaera provides merging and diagnostic support for ontologies in many formatsontologies in many formats

• It improves performance over existing toolsIt improves performance over existing tools• It has been used by people of various training backgrounds It has been used by people of various training backgrounds

in government and commercial applications and is available in government and commercial applications and is available for use.for use.

• http://www.ksl.Stanford.EDU/software/chimaera/ -movie, tutorial, papers, link to live system, etc.

Discussion Today• Chimaera addressed merging and diagnostic tasks

directly• It aimed at focusing human attention where humans

would make updates• It aimed to make users function at a higher level of

training that what they had

• Evolved to 3 industrial systems:• VerticalNet, Cisco, Sandpiper• TW Ontology Instance Evaluator – next generation

of diagnostics. Same general approach for tests; different technological foundation

OntologyBuilder

Configuration

http://www.research.att.com/sw/tools/classic/tm/ijcai-95-with-scenario.htmlhttp://www.research.att.com/sw/tools/classic/tm/ijcai-95-with-scenario.html

Drexel Univ.IHI – Inst. For Healthcare Informatics

Ontology Creation and Maintenance Environment Needs

• Diagnostics/Explanation (Chimaera, CLASSIC,…)• Merging and Difference (Chimaera, Prompt, Ontolingua, …)• Translators/Dumping (Ontolingua, …)• Distributed Multi-User Collaboration (OntologyBuilder,…)• Versioning (OntologyBuilder,…)• Scalability. Reliability, Performance, Availability

(Shoe,OntologyBuilder,…)• Security (viewing, updates, abstraction, authoritative

sources…)• Ontology Library systems (Ontolingua, DAML, PlanetOnt, …)• Business needs – internationalization, compatibility with

standards (XML,…)• Provenance support (languages and environments)

Prompt Today• http://protege.cim3.net/cgi-bin/wiki.pl?Prompt

• compare versions of the same ontology

• map one ontology to another

• move frames between included and including project   

• merge two ontologies into one

• extract a part of an ontology

TW OIE• In many ways, a next generation diagnostic

environment

• Aimed at instance evaluation

• Uses very different approach – different approach to reasoning and checking

• We will consider this and related efforts in our discussion of priorities for your own environments you would design today

Today’s Environment• Discussion of historical tools and

requirements in today’s environment– Consider technological changes– Social issues (more distributed, more

collaborative, …)– Design considerations for long lived systems…

may lead to social and modeling conventions including naming “e.g. has-…”, separating out information that is likely to change over time, …

Evolving Environment Needs - Facilitated Discussion

• Diagnostics/Explanation• Merging and Difference• Translators/Dumping • Distributed Multi-User Collaboration • Versioning • Scalability. Reliability, Performance, Availability • Security • Ontology Library systems • Business needs• Provenance support

Extras