Towards Linked Ontologies and Data on the Semantic Web

Jie Bao, Rensselaer Polytechnic Institutebaojie@cs.rpi.edu, http://www.cs.rpi.edu/~baojie

Oct 1st, 2009

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Outline

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Personal Background & Research Overview

Linked Ontologies: a modular ontology approach

Linked Data: a semantic wiki based approach

Ongoing/Future Work

Personal Background

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Research Overview

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Research Overview

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They are all about the power of linking…

Research Overview

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Linked Ontologies

Linked Data

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Part I

Linked Ontologies

Roadmap

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SemanticWeb

Why not owl:imports?

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owl:imports

Why not owl:imports?

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owl:imports

(Alice, 2001) (Bob, 2009)

Analogy: Paper Writing in the OWL fashion

Recent development in Web…

In this paper, we extend the algorithm A proposed by (Alice,2001) …

Recent development in algorithms …

In this paper, we present two algorithms A and B to …

Why not owl:imports?

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(Bob, 2009)

Analogy: Paper Writing in the OWL fashion

In this paper, we extend the algorithm A proposed by

In this paper, we present two algorithms A and B to …

Recent development in algorithms …

Recent development in Web…

P-DL: Importing akin to Citation

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P-DL imports

(Alice, 2001) (Bob, 2009)

Paper(Bob2009)

{Bob2009} ⊑propose.{AlgC}

{AlgC} ⊑extend.{AlgA}

{Bob2009} ⊑cite.RecentDev

Paper(Alice2001)

{Alice2001} ⊑propose.{AlgA}

{Alice2001} ⊑propose.{AlgB}

{Alice2001} ⊑cite.RecentDev

[ISWC 2006; ASWC 2006; AAAI 2007, AAAI 2008]

P-DL = Package-based Description Logics

P-DL: Semantics

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PeopleAnimals

O1 O2

Only “relevant” local domains are connected

Expressions are interpreted in local domains (e.g., neg)

Modular ontology languages: Comparison

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Distributed DL E-Connection P-DL

What can you import?

Nothing Concept name, Nominal name

Concept, Role, and Nominal name

What can you do with the imported names syntactically?

(bridge rules between concepts and between roles)

Use it in the range of a (link) role

Free use, except that imported roles can not be used in role inclusions

What is the result semantically?

Decidability with BR between concepts.

Decidability Decidability , Transitive Reusability, Preservation of Unsatisfiability

Roadmap

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SemanticWeb

Reasoning with P-DL

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Major Considerations

[WI 2006]

P-DL Federated Reasoning

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Dog

Dog ⊑ AnimalP2 P1

What is a “Dog”?

“Dog” is a type of “Animal”

P-DL Federated Reasoning

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messages

Roadmap

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SemanticWeb

Privacy Matters

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A reasoner may pose queries to another reasoner (of a remote ontology)

However, not everything is public.

[WI 2007]

Private Knowledge

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Locally visible:Has date

Q: Has date?A: Unknown

Bob’ schedule ontology

Q: Busy?A: Yes

Q: Has dinner?A: Unknown

indistinguishable

Privacy-Preserving Reasoners

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Dummy Reasoner

“Combina-tion Safe” Reasoner

Naive Reasoner

Gives information

Always answer “U”

? Always answer faithfully

Safety scope

All ontologies

Ontologies that have no hidden knowledge

More informative

More general

Privacy-Preserving Reasoners

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Reasoner I: iff a statement is hidden, answer “unknown”.

Reasoner II: iff a statement may be used in inferring a hidden statement, answer “unknown”.

Reasoner III: it will NOT give more knowledge (except the public knowledge) about the signature of the hidden KB. Using the notion of “Locality” in DL.

(See [WI 2007] for formal definitions)

Mor

e in

form

ativ

eM

ore

gene

ral

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Part II

Linked Data- A semantic wiki based approach

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Roadmap

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SemanticWeb

Why Semantic Wiki

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Linked data ready Support both

structured and unstructured data.

Simple syntax, Low learning curve

Inherent collaboration support

Browser-based, Cross-platform

Semantic Wiki

Example: Semantic History

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Turn wiki revision history into semantic data

Demo site: http://tw.rpi.edu/semhis

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Semantic History (v1)

• Expose history in RDF using PML• Query data and its provenance metadata

http://tw.rpi.edu/Help:SemanticHistory

RDF/XML data displayed in Tabulator

Semantic History (v2)

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[SDOW 2009]

User makes edits

SMW

The Semantic History (SH) extension captures edit actions

{{SH_Triple |…}}

{{SH_Add |…}}

{{SH_Delete|…}}

SH Templates(customizable

)

Revision history

SH Templates generates semantic descriptions of revision history

Triple Representatio

n of history

User

Triplified revision history are added to and managed by the SMW

Applications use the triplified revision history for various purposes

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Semantic History: Example (Provenance tracking)

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Who has changed the first name of James Hendler? http://tw.rpi.edu/proj/semhis.wiki/index.php/Example_4

Semantic History (v2): Example (Statistics and Visualization)

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Other Data Generation Services

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A few other SMW extensions I have worked on:

Roadmap

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SemanticWeb

Concept Modeling

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PersonNameRoleAliasAffiliation

Project

NameMember

IssueIDProjectAssignee

Jim Hendler ProfessorhasRole

Person

rdfs:subClassOf

Alice

John

hasUncleAlice

BobJohn

isParentOf

isBrotherOf

RDF Modeling

Relational Modeling

Rule Modeling

Rules: Logic Programs

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RightHanded(x):-Person(x), not LeftHanded(x).

{{LP Rule |body= 1::Person; 1:not:LeftHanded |head= RightHanded }}

Example: every person is by default right-handed, unless that person is known to be left-handed:

See details at: http://tw.rpi.edu/proj/cnl/Template:LP_Rule

[ACITA 2009]

Rules: Integrity constraints

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IC describes errors in a dataset

Example:notOK :- Person(x), not HasGender (x,y)

See details at: http://tw.rpi.edu/dev/cnl/Integrity_Constraint

Roadmap

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SemanticWeb

Semantic Wiki: Application Workbench

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Wiki DB Triple Store Online dataData Layer

Map Data EvaluationPublication

Management

Still many not yet

mentioned…

Wiki Layer

App.Layer

(Semantic) Wiki Scripting

Semantic Template

Semantic Query

(PHP, Javascript) Wiki Extensions

HaloExtension

Parser Function

Concept Modeling: RDF, Relational Modeling, Rules

Semantic Forms

ProjectManagement

Remote SemWiki

Group Info. Management

[ASWC 2009]

Case Study: CNL Wiki

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A Wiki-based ontology editor

Supports ontology representation in Controlled Natural Languages (CNL).

http://tw.rpi.edu/proj/cnl[CNL 2009]

Case Study: CNL Wiki

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Class(Rabbit partial intersectionOf(animal restriction(eat someValuesFrom(FreshVegetable)))

OWL: “Rabbit is Animal and eats some fresh vegetable”

OWL: “Rabbit is Animal and eats some fresh vegetable”

Us wiki templates to create OWL meta-model extensions for SMW

Us wiki templates to create OWL meta-model extensions for SMW

Form-based editing interface associated with templates

Form-based editing interface associated with templates

Case Study: CNL Wiki

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Case Study: RPI Map

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Ongoing/Future Work

Some Other Recent Research Activities

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TAMI & AIR (2009) Policy testbed and AIR formulation(With Li Ding and

Ankesh Khandelwal)

OWL Working Group (2008-2009) Authored rdf:plainLiteral and OWL Quick Reference Guide

Integrity Constraint and Closed World Reasoning (2008-2009) IC language for Semantic Web(with Jiao Tao)

INDUS (2003-2006) Semantic data integration in the bioinformatics domain

Some Ongoing/Planned Work

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Linked Data Turn government data into wiki data /RDF Semantic search with RDFa / SMW

Policy and Trust Privacy-preserving query with SMW Information accountability and access control in SMW Trust computation based on semantic history

Web-scale Computing Scalable “is-a” reasoner OWL-RL reasoner

Long-term Goal

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Email Picture

Phone Call

Shopping

music

video

Web

Server

Farm

Conclusion

“A little semantics goes a long way”

a.k.a. Hendler Hypothesis

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Acknowledgements Work at ISU: Vasant Honavar (Ph.D. advisor),

Giora Slutzki, George Voutsadakis, Doina Caragea

Work at RPI: James Hendler (supervisor), Deborah L. McGuinness, Peter Fox, Li Ding, Zhenning Shangguan, Rui Huang, Jin Guang Zheng, Ankesh Khandelwal

Funding support from NSF, NIH, USDA, Army Research Laboratory and DARPA.

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References (modular ontologies)

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Bao, J., Voutsadakis, G., Slutzki, G. Honavar, V. Package based Description Logics. Book Chapter in Ontology Modularization, pages 349-371. Berlin: Springer, 2009

Bao, J., Voutsadakis. G., Slutzki, G. and Honavar, V. On the Decidability of Role Mappings Between Modular Ontologies. In AAAI 2008, pages 400-405.

Bao, J., Slutzki, G., and Honavar, V. Privacy-Preserving Reasoning on the Semantic Web . In Web Intelligence 2007. ( Slides) pages 791-797.

Bao, J., Slutzki, G., and Honavar, V. A Semantic Importing Approach to Knowledge Reuse from Multiple Ontologies . In AAAI 2007, pages 1304-1309.

Bao. J., Caragea, D., and Honavar, V. A Tableau-based Federated Reasoning Algorithm for Modular Ontologies , In Web Intelligence 2006, pages 404-410.

Bao. J., Caragea, D., and Honavar, V. On the Semantics of Linking and Importing in Modular Ontologies . In International Semantic Web Conference 2006, LNCS 4273, pages 72-86.

Bao. J., Caragea, D., and Honavar, V. Modular Ontologies - A Formal Investigation of Semantics and Expressivity . In Asian Semantic Web Conference 2006, LNCS 4185, pp. 616-631. http://tw.rpi.edu/wiki/Jie_Bao_Publication

References (semantic wikis) Bao, J. Ding, L., Huang, R., Smart, R., Braines, D., Jones, G. A Semantic Wiki

based Light-Weight Web Application Model, In Proceedings of the 4th Asian Semantic Web Conference, pp. In Press, 2009 .

Bao, J., Ding, L., & McGuinness, D.L. Semantic History: Towards Modeling and Publishing Changes of Online Semantic Data, In The 2nd Social Data on the Web workshop (SDoW2009), In Process.

Bao, J., Ding, L., Smart, R., Braines, D., & Jones, G. Rule Modeling using Semantic MediaWiki, In 2nd Annual Conference of the International Technology Alliance, pp. In Process, 2009

Bao, J., Smart, P., Braines, D., & Shadbolt, N. A Controlled Natural Language Interface for Semantic Media Wiki Using the Rabbit Language. In Workshop on Controlled Natural Language (CNL) 2009.

Bao, J. and Hendler, J., Ding., L. Knowledge representation and query in semantic mediawiki: A formal study. In Tetherless World Constellation (RPI) Technical Report, No TW-2008-42, http://tw.rpi.edu/wiki/TW-2008-42, 2008.

Bao, J., Ding, L., McGuinness, D., Hendler, J. Towards Social Webtops Using Semantic Wiki, In International Semantic Web Conference (ISWC), Poster Track, 2008

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http://tw.rpi.edu/wiki/Jie_Bao_Publication

Backup

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P-DL: Additional Properties

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Dog

Dog Animal⊑

Pet Animal

O1 O2 O3

⊑ ⊑

P-DL Federated Reasoning

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Bob2009

Alice2001

cite

Privacy-Preserving Reasoning

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Protect hidden knowledge as if it is incomplete knowledge Both are answered “unknown”

But when to answer “unknown”? People may combine “safe”

answers to infer hidden knowledge

Privacy-Preserving Reasoning

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QueriesYes

Unknown

Semantic MediaWiki (SMW)

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It is the most popular semantic wiki system extending MediaWiki

Mediawiki: What you edit what you see

Semantic MediaWiki

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SMW: What you edit(Modeling Script)

what you see

typed link (property)

To author knowledge

Semantic MediaWiki

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SMW: What you edit(Querying Script)

what you see

To retrieve knowledge

SMW Semantics and Complexity (Theory)

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See proofs in [TW-2008-42]

SMW RDF

Modeling Language

Translatable into positive logic programs

NL-complete

• NP-complete;• P-complete for grounded graph [Bruijn and

Heymans 2007]

Query language Translatable into positive logic programs• P-complete;• In L without subqueries

(SPARQL) P-complete [Perez et al 2006]

Recall that L NL P NP

Formalize SMW Query (Theory)

{{#ask: [[Category:A]][[p3::category:B]] or

[[p.p1.p2::<q>[[Category:D]] or [[p1::<q>[[SomePage]]</q>]]</q>||!v||<q>[[Category:E]]</q>

]]}}

_result(x) :- _tmp0(x). _tmp0(x) :- A(x), p3(x,x0),

x0=category:B. _tmp0(x) :- p(x,x2),

p1(x2,x3), p2(x3,x1), _tmp9(x1).

_tmp9(x1) :- _tmp12(x1). _tmp12(x1) :- D(x1). _tmp12(x1) :- p1(x1,x4),

x4=SomePage. _tmp9(x1) :- x1!=v. _tmp9(x1) :- E(x1).

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Case Study: RPI Map

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