collaborative ontology building with wiki@nt

Nov 8,2004 EON2004 - ISWC2004, Hiroshima, Japan

1

Collaborative Ontology Building with Wiki@nt

Preliminary Report

Jie Bao and Vasant HonavarArtificial Intelligence Research Laboratory

Computer Science DepartmentIowa State University

Ames IA USA 50010{baojie,honavar}@cs.iastate.edu

Nov 8,2004 EON2004 - ISWC2004, Hiroshima, Japan 2

Outline Overview


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


Wiki@nt Wiki : a kind of collaborative d

ocumentation writing/website building tool

@nt = Ont + Ant Ont for ontology Ant to denote a type of collabora

tive agent Wiki@nt: a collaborative ontol

ogy editor with wiki


Ants for ontologyWithout SHOE how can you be a RACER?Without Sesame how can you make OIL?

Semantic Web is a plan of goodBut without ontology it’s only a nil.

Everyone adds a small piece of brick It takes the labor of many to make the Rome

real.

Let’s create ontology hand in handJust like ants build their hill.


Proposed ApproachWiki Engine for

Collaborative EditingUnderlying Language to support

modularity and reconciliationBrowser-based Editor

Agent C

om

munity

Dynamic loading of Partial Model

Seria

lizatio

n


Outline Overview Ontology Language Extension


Ontology Language Extension - to support modularity POWL: package-based ontolo

gy language Package is an ontology modu

le 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)

P1

P2

public

private

P1

P2

public

private


Interface


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 ) B:SubClassOf( 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)


Example with P and O constructors

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


Outline Overview Ontology Language Extension Wiki@nt Architecture


Wiki@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.


http://boole.cs.iastate.edu:9090/wikiont


Architecture – Wiki Engine Provides a web interface for ontology editor Translates the Wiki@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 <-> package

Based on JSPWiki engine


Architecture – Wiki Engine/Markup Script

We defined a set of markup script tags as the syntax of the ontologies in Wiki@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: [animal:Dog] [rdfs:subClassOf][animal:Carnivore] Shown as

‘P’ and ‘O’ axioms can be presented in triple syntax.

[term_uri] [powl:public][pkg_uri] [uri1][wiki:stronger][uri2]


Script Example; [test..AnonymousClass107|#107]\\* [test..AnonymousClass107|107] [owl..allValuesFrom] [camera..Body

WithNonAdjustableShutterSpeed]\\* [test..AnonymousClass107|107] [owl..onProperty] [camera..body]\\* [test..AnonymousClass107|107] [rdf..type] [owl..Restriction]\\; camera..Large-Format\\* [camera..Large-Format] [rdf..type] [owl..Class]\\* [camera..Large-Format] [rdfs..subClassOf] [test..AnonymousClass10

7|107]\\* [camera..Large-Format] [rdfs..subClassOf] [camera..Camera]\\

http://boole.cs.iastate.edu:9090/wikiont/Wiki.jsp?page=camera..Large-Format


Architecture – Wiki Engine/Modularization An ontology could be composed by sever

al 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@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.

Ontology

Package

Block/WikiPage

axiom


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] [wiki:stronger][Package2], axiom level, eg.[Package1:1g][wiki:stronger][Package2:2d].

Default defeating rules Local-first: a local package axiom defeats axiom from im

ported package Higher-first: social order of the author, eg. administrator

defeats common user


Architecture – Wiki Engine/Memory Mgmt

While most of the popular ontology editors have in-memory model for edited ontology, Wiki@nt doesn't.

An in-memory model limits the scalability of the system In-memory model implicitly assumes the existence of a glo

bal ontology, requires monotonicity. We store ontology as a set of separated, possibly dist

ributed blocks in Wiki@nt. Each block is serialized to a wiki page when it's not being a

ctively 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.


Architecture – Wiki Engine/Transaction Mgmt

Wiki@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.


Architecture – Agent Management

Each participant in Wiki@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.


Architecture – Ontology I/O We can export wiki pages as a single ontology file, o

r 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 axiom

s, eg: package1.Dog Defeated axioms will be removed


Outline Overview Ontology Language Extension Wiki@nt Architecture Closing Remarks


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 P+O+OWL Scalability test Many others……


Thank you !Contact:

Jie Bao215 Atanasoff Hall, Iowa State UniversityAmes IA 50010 [email protected], 1-515-294-7331http://www.cs.iastate.edu/~baojie

More Information: Bao, Jie and Honavar, Vasant (2004) Ontology Language Extensions to Support Loca

lized 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@nt - A multi-agent based ontology building environment . Technical Report, Computer Science, Iowa State University.


Backups


@ntHill – Whole Picture

OntologyRepository

Wiki@nt P-OWL

Hum

an

Exp

ert

Email list

Newsgroup

Forum

Blog

Wiki

P2P node

SemanticRSS-aware

Channel

SemanticRSS-aware

Channel

SemanticRSS-aware

Channel

Agents: Ontology

MiningBrowser

Onto

logy A

lignm

ent

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

A

B

C D

collaborative ontology building with wiki@nt

Technology

ontology module

ontology ant

ontology hand

ontology repository

ontology withoutshoehow

address wiki

package1 wiki

collaborative ontology