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Knowledge Provenance in Semantic Wikis
Li Ding, Jie Bao, and Deborah McGuinnessTetherless World Constellation, Rensselaer Polytechnic Institute
Troy, NY USA
Presented at AGU 2008 Fall Meeting 15–19 December 2008, San Francisco, California
Emerging Web Semantics
• Web 1.0: online text• Web 2.0: collaborative
online text• Web 3.0: collaborative
online knowledge
Web 1.0
Web 2.0
Web 3.0Collaborative A
uthoring
Structure and Semantics Preservation
Motivation Question
What has been done to my homepage?
• Existing approaches– Internet Archive: “when”
– Wiki history: “when”, “who”
• In Semantic Wiki– Represent changes
– Query changes
Semantic History• Automatically convert Wiki History to
Knowledge Provenance interlingua – PML (Proof Markup Language). This links semantic web data to information about where it came from.
• We provided triple level granularity for knowledge provenance in Semantic Media Wiki
• We support semantic queries over knowledge provenance as well as content
Encoding Wiki History Using PML
Version 2 of Page A
Version 1 of Page A
InferenceStep X
NodeSet A1
NodeSet A2hasConclusion
hasConclusion
hasAntecedent
isConsequentOf
User:Joe
ex:Revision
17:17, October 22, 2008
hasInferenceEngine
hasInferenceRule
hasCreationDatatime
6
Knowledge Provenance Interlingua
• PML1 was introduced in 2002– It has been used in multiple contexts ranging from explaining
theorem provers to text analytics to machine learning.– It was specified as a single ontology
• PML2 improves PML1 by – Adopting a modular design: splitting the original ontology into
three pieces: provenance, justification, and trust• This improves reusability, particularly for applications
that only need certain explanation aspects, such as provenance or trust.
– Enhancing explanation vocabulary and structure• Adding new concepts, e.g. information• Refining explanation structure
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PML Provenance Ontology
• Scope: annotating provenance metadata
• Highlights – Information
– Source Hierarchy
– Source Usage
Initial Results
•(cur) (last) 17:17, October 22, 2008 Li (Talk | contribs | block) (420 bytes) (rollback | undo) •(cur) (last) 20:42, August 24, 2008 Baojie (Talk | contribs | block) (345 bytes) (undo) •(cur) (last) 23:44, August 15, 2008 Baojie (Talk | contribs | block) (331 bytes) (undo)
Wiki Page “interval t1”Wiki Page “Triple 1”Wiki Page “DLM”
Ongoing WorkSMW History and Temporal RDF
tw:DLM
Deborah
Triple 1foaf:firstName
Interval t1
begin-datetime
end-datetime
2008-11-12
2008-11-14
interval
interval
rdf:subject
rdf:predicate
rdf:object
• Referring RDF triple via Reification• integrating temporal data within RDF
Claudio Gutiérrez, Carlos A. Hurtado, Alejandro A. Vaisman - Temporal RDF. In ESWC pp. 93-107, 2005
Ongoing WorkSemantic History Computation
PO1 PO2 PO3 (triple, r_add, r_del)
R1 X (po1,r1,null)
R2 X (po1,r1,t2) (po2,r2, null)
R3 X X (po1,r3,null)
R4 X X (po1,r3,t4) (po3,r4,null)
R5 X X (po1,r5,null) (po2.r2,r5)
R6 X (po1,r5,r6) (po2,r6,null )(po3,r4,r6)
R7 X (po1,r7,null) (po2,r6,r7)
Rn
Change of an RDF wiki page POi:Property and object, Ri: for revision id.
Space complexity DELTAO(m)<= DELTA <=O(m*n)m: # of triplesn: # of revisions
Depends on change rateTriple/revision
Alternative is bitmapbitmap delta
non rdf:type (smw_rels2 ) S_id, P_id, O_id, rev_id_add, rev_id_del
Rev_id, rev_page, author, timestampRevision Table
rdf:type (smw_inst2) S_id, O_id, rev_id_add, rev_id_del
Link table Rev_id, => linked template_page_id
Potential applicationsComputing Trust using History
Trust in fragments detected by analyzing revision history (who edited which fragment)
The lighter color corresponds to low trust
Conclusion and Future Work• We have exposed wiki history information
about Semantic Web data using the PML Knowledge Provenance Interlingua
• PML-based wiki history improves linking and access to Semantic Media Wiki data
• We adopted a Temporal RDF approach which is compatible with Semantic Query capabilities offered by Semantic Media Wiki
• The next version of Semantic history will implement Temporal RDF in SMW
