Towards Linked Ontologies and Data on the Semantic Web
description
Transcript of Towards Linked Ontologies and Data on the Semantic Web
Towards Linked Ontologies and Data on the Semantic Web
Jie Bao, Rensselaer Polytechnic [email protected], 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
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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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