Collaborative Ontology Building with Wikint Preliminary Report - PowerPoint PPT Presentation

Title: Collaborative Ontology Building with Wikint Preliminary Report


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Collaborative Ontology Building with
Wiki_at_ntPreliminary Report

• Jie Bao and Vasant Honavar
• Artificial Intelligence Research Laboratory
• Computer Science Department
• Iowa State University
• Ames IA USA 50010
• baojie,honavar_at_cs.iastate.edu

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Outline

• Overview

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Motivation

• Ontology construction is a collaborative process
• direct cooperation among domain experts, and
  software agents
• indirect cooperation through reuse of published
  ontologies.
• Integration different participants have only
  partial knowledge of the domain, and hence can
  contribute part of the ontology.
• Modularity helps!
• Reconciliation Semantic mismatches and logical
  inconsistencies between independently developed
  ontologies are unavoidable.
• Existing ontology editors (Protégé, OilEd) are
  mostly focused on stand-alone ontology
  development rather than collaborative
  construction of ontologies.
• How about KAON, OntoEdit, WebODE, CODE ? Lack of
  modularity

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Wiki_at_nt

• Wiki a kind of collaborative documentation
  writing/website building tool
• _at_nt Ont Ant
• Ont for ontology
• Ant to denote a type of collaborative agent
• Wiki_at_nt a collaborative ontology editor with wiki

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Ants for ontology

• Without SHOE how can you be a RACER?
• Without Sesame how can you make OIL?
• Semantic Web is a plan of good
• But without ontology its only a nil.
• Everyone adds a small piece of brick
• It takes the labor of many to make the Rome real.
• Lets create ontology hand in hand
• Just like ants build their hill.

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Proposed Approach
Wiki Engine for Collaborative Editing
Underlying Language to supportmodularity and
reconciliation
Browser-based Editor
Dynamic loading of Partial Model
Agent Community
Serialization
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Outline

• Overview
• Ontology Language Extension

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Ontology Language Extension - to support
modularity

• POWL package-based ontology language
• Package is an ontology module with clearly
  defined access interface
• Each term is defined in a package and has its
  scope
• Eg public, private
• Constructor P (Bao and Honavar 2004)

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Interface
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Ontology Language Extension- to handle
inconsistency

• A t, but A,B ! t
• A DisjointClasses(Plant,Animal)
• A SubClassOf( Dog , Carnivore )
• A SubClassOf( Carnivore, Animal)restriction(eats
  allValueFrom(Animal)) -t
• B SubClassOf( Grass , Plant )
• BSubClassOf( SickDog, Dog)restriction(eats
  someValueFrom(Grass))
• This can be resolved with defeasible axioms
• Partial orders are assigned to axioms stronger
  axioms can defeat weaker axioms.
• Constructor O ( Heymans 2002)

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Example with P and O constructors

• Two packages
• (2d) defeats the general rule (1g).

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Outline

• Overview
• Ontology Language Extension
• Wiki_at_nt Architecture

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Wiki_at_nt

• Using wiki to edit OSHOQP(D) ontology.
• An ontology module is composed of one or more
  wiki pages
• Multiple users can edit the same content, with
  wiki version control, transaction management and
  memory management.
• An ontology is saved intoor loaded from a set of
  wiki pages and managed by an ontology
  repository.

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• http//boole.cs.iastate.edu9090/wikiont

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Architecture Wiki Engine

• Provides a web interface for ontology editor
• Translates the Wiki_at_nt script to HTML code to be
  shown in the web browser.
• Manages the storage of wiki pages, in plain file
  or database.
• Provides version control.
• Provides transaction management.
• Provides memory management.
• Compose/Decompose ontology lt-gt package
• Based on JSPWiki engine

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Architecture Wiki Engine/Markup Script

• We defined a set of markup script tags as the
  syntax of the ontologies in Wiki_at_nt.
• The syntax is an extension to OWL to support
  package and partial order on axioms.
• Wiki markup script is a human readable syntax
  equivalent to the N-Triple syntax. Each axiom is
  assigned a URI
• Eg animalDog rdfssubClassOfanimalCarnivor
  e
• Shown as
• P and O axioms can be presented in triple
  syntax.
• term_uri powlpublicpkg_uri
• uri1wikistrongeruri2

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Script Example

• test..AnonymousClass107107\\
• test..AnonymousClass107107
  owl..allValuesFrom camera..BodyWithNonAdjustabl
  eShutterSpeed\\
• test..AnonymousClass107107 owl..onProperty
  camera..body\\
• test..AnonymousClass107107 rdf..type
  owl..Restriction\\
• camera..Large-Format\\
• camera..Large-Format rdf..type
  owl..Class\\
• camera..Large-Format rdfs..subClassOf
  test..AnonymousClass107107\\
• camera..Large-Format rdfs..subClassOf
  camera..Camera\\

http//boole.cs.iastate.edu9090/wikiont/Wiki.jsp?
pagecamera..Large-Format
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Architecture Wiki Engine/Modularization
Package

• An ontology could be composed by several
  packages, and one package could be reused by
  multiple ontologies.
• A package is a logic module for an ontology,
  usually from a single author.
• A block is a set of related axioms inside a
  package, and will be physically mapped to a wiki
  page.
• In Wiki_at_nt, we choose axiom groups as ontology
  blocks. Each axiom group contains triples with
  same subject.
• For example,the axiom groups in Animal Ontology
  package(1) will be Dog, Carnivore, eats, and
  billy.

axiom
Block/WikiPage
Ontology
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Architecture Wiki Engine/Inconsistency

• Inconsistency among modules should be resolved
  when integrating the modules.
• We assume each package should be consistent.
• A partial order can be specified on
• package level, eg. Package1 wikistrongerPack
  age2,
• axiom level, eg.Package11gwikistrongerPacka
  ge22d.
• Default defeating rules
• Local-first a local package axiom defeats axiom
  from imported package
• Higher-first social order of the author, eg.
  administrator defeats common user

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Architecture Wiki Engine/Memory Mgmt

• While most of the popular ontology editors have
  in-memory model for edited ontology, Wiki_at_nt
  doesn't.
• An in-memory model limits the scalability of the
  system
• In-memory model implicitly assumes the existence
  of a global ontology, requires monotonicity.
• We store ontology as a set of separated, possibly
  distributed blocks in Wiki_at_nt.
• Each block is serialized to a wiki page when it's
  not being actively edited, and is loaded into
  memory only when it's needed.
• A (local or remote) partial ontology model is
  dynamically loaded into local memory during an
  editing or reasoning process, from a set of pages.

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Architecture Wiki Engine/Transaction Mgmt

• Wiki_at_nt denies the write-access of agents to a
  page and related pages if it is locked by some
  other agents.
• If a class is under editing/lock, its
  superclasses in the class hierarchy and its
  instances will be locked.
• If a property is under editing/lock, its
  superproperties in the property hierarchy will be
  locked.
• If a concept, property or instance is under
  editing/lock, all other concepts, properties or
  instances in the same wikipage(axiom group) will
  be locked.
• If a package is locked, all packages that import
  it will be locked.
• Locking is propagated by recursively applying
  these rules.

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Architecture Agent Management

• Each participant in Wiki_at_nt is considered as an
  agent.
• Each agent is assigned different privileges, such
  as ontology administrator and package manager.
• An agent can become an editor of an existing
  ontology module or create a new module.
• RPC interface is reserved for software agents.

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Architecture Ontology I/O

• We can export wiki pages as a single ontology
  file, or read an ontology file into Wiki Ontology
  Repository.
• The relevant portion of an ontology is extracted
  or assembled from the wiki pages.
• Each loaded ontology is assigned a unique name,
  eg. http//mydomain.org/animal/
• Reduce to standard OWL
• Package could be eliminated by adding a prefix to
  its axioms, eg package1.Dog
• Defeated axioms will be removed

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Outline

• Overview
• Ontology Language Extension
• Wiki_at_nt Architecture
• Closing Remarks

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Future work

• Better transaction management
• What is sufficient local model in reasoning?
  For memory management
• Better policy to assign partial order over axioms
• Better graphic, interactive UI
• Java/Applet client
• Plugins for Protégé ?
• More formal versioning representation
• A reasoner over POOWL
• Scalability test
• Many others

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Thank you !

• Contact
• Jie Bao
• 215 Atanasoff Hall, Iowa State University
• Ames IA 50010 USA
• Baojie_at_cs.iastate.edu
• 1-515-441-0491, 1-515-294-7331
• http//www.cs.iastate.edu/baojie
• More Information
• Bao, Jie and Honavar, Vasant (2004) Ontology
  Language Extensions to Support Localized
  Semantics, Modular Reasoning, and Collaborative
  Ontology Design and Ontology Reuse . Technical
  Report, Computer Sicence, Iowa State University.
• Bao, Jie and Honavar, Vasant (2004) Collaborative
  Ontology Building with Wiki_at_nt - A multi-agent
  based ontology building environment . Technical
  Report, Computer Science, Iowa State University.

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Backups
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_at_ntHill Whole Picture
C
D
A
Ontology Alignment
Human Expert
Wiki_at_nt
P-OWL
Agents Ontology Mining
Browser
OntologyRepository
B
SemanticRSS-awareChannel
Email list
Wiki

• Version Control
• Redundancy Check
• Conflict Check
• Cross Validation

SemanticRSS-awareChannel
Newsgroup
Blog
Forum
P2P node
SemanticRSS-awareChannel