1) The document proposes adding two new constructs, rdf:context and rdf:imports, to make contexts explicit in RDF graphs. 2) rdf:context would associate a context definition with an RDF graph, and rdf:imports would represent how knowledge is transferred between contexts during import operations between graphs. 3) Making contexts explicit would allow for reasoning about compatibility between contexts and partial reuse of knowledge between contexts through relations like compatible and incompatible.

1. Contexts and Importing in RDF
Jie Bao, Li Ding, and Deborah L. McGuinness
Tetherless World Constellation
Rensselaer Polytechnic Institute
Troy, NY, 12180-3590, USA
{baojie,dingl, dlm}@cs.rpi.edu

2. Context Matters
- Provenance
Stanford
hasRole PostDoc
stanford:LiDing
HasAffiliation Stanford
hasRole
owl:sameAs
RPI
ResearchScientist
hasRole
rpi:LiDing
HasAffiliation RPI
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3. Context Matters
- Assumptions
rdf:type
foaf:mbox owl:InverseFunctionalProperty
ISWC
Jie Bao foaf:mbox
baojie@cs.rpi.edu
J. Bao foaf:mbox
Foo forum
janesmith456 foaf:mbox
n/a
johnsmith123 foaf:mbox
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4. Context Matters
- “World”
“Matrix”
“Real World”
South Park
killed
THEY Kenny
rdf:type rdf:type
Fictional People
0100010111010101010101010…
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5. Contexts are
• Something related to the meaning of a sentence
– Provenance (who, when, where, how, etc)
– Assumptions (e.g., OWA, UNA)
– World
– …
• Claim: when a triple is published/reused/inferred,
its context should be made explicit.
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6. Wait
• Don’t we already have
– Named graph
– C-OWL
– N3 quotation
– Contexts in AI
–…
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7. Named Graph
Name = context
Contexts are more than
names
Graph_RPI
• One triple may be in
{:LiDing :hasRole multiple contexts
:ResearchScientist.} • One context may be
reused
• Relations between
contexts need to be
explicit, too.
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8. C-OWL
South Park
• C-OWL provides an
People ontology mapping
language that respects
contexts.
into
• Knowledge transfer is
RealWorld controlled.
Fictional People
• Contexts are more than
mapping
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9. N3Logic
rpi:LiDing says • Again, contexts are
{rpi:LiDing :hasRole more than quotation.
:ResearchScientist.}
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10. Our Proposal
• Based on named graph
• Add two constructs
• rdf:context
• rdf:imports
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11. Adding Contexts to RDF
Part I: rdf:context Part II: rdf:import
G1 rdf:imports G2.
G rdf:context C. G1 rdf:context C1.
G2 rdf:context C2.
C may give a context • Importing as citation
definition document • How knowledge G2 to G1
transferred from
C agent LiDing. can be controlled by
relations between C1 and
C semantics OWL_Full C2.
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12. Partial Reuse
{s1 p1 o1.} rdf:imports
{s3 p3 o3.}
rdf:context C1. rdf:context C3.
{s2 p2 o2.} rdf:imports
rdf:context C2.
C3
C3 rdfc:compatibleWith C1.
C3 rdfc:incompatibleWith C2.
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13. Reasoning with Contexts
Context relations Context rules
• Compatible • C is compatible with
• Incompatible contexts with agent
• Extend “rpi:LiDing”
• In • C is compatible with
contexts that are
compatible with C2
Can be specified in OWL,RIF
or other languages
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14. Open Issues
• Context specification
– Provenance model?
– Context relation vocabulary?
• Formal semantics of contexts
• Default contexts
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