Steffen Staab's Presentation at SSSW 2011

Web Science & Technologies
University of Koblenz ▪ Landau, Germany

Provenance in the Semantic Web

Steffen Staab

Joint work with
Simon Schenk, Renata Dividino, Christoph Ringelstein

Institut WeST – Web Science & Technologies

Semantic Web Web Retrieval Interactive Web Multimedia Web Software Web

eGovernment eMedia eScience eOrganizations ePerson

Institute for Computer Institute for Leibniz Institute for
Science Information Systems Social Sciences (GESIS)
WeST Steffen Staab Summer School Semantic Web
staab@uni-koblenz.de 2

Do you care where your data comes from?


How to loose 1,000,000,000 US$ in half a day

WeST
Via @Bauckhage Steffen Staab Summer School Semantic Web

+++ „Los Angeles (dpa) – In der
kalifornischen Kleinstadt Bluewater
soll es nach einem Bericht des
örtlichen Senders vpk-tv zu einem
Selbstmordanschlag gekommen
sein. Es habe in einem Restaurant
zwei Explosionen gegeben...“ +++

German Press Agency DPA, 10 Sep 2009


Guerilla Marketing


Loosing your reputation quickly…

Hoax
better check who said what when and
whether you actually want to trust
some information


Defining Provenance

Provenance … means
 the origin… of something, or
 the history of the ownership or location of an object.
 The term was …used for works of art, but is now …
including science and computing. …
 In most fields, the primary purpose of provenance is to
confirm or gather evidence as to the time, place, and—
when appropriate—the person responsible for the creation,
production, or discovery of the object.
 This will typically be accomplished by tracing the whole
history of the object up to the present
http://en.wikipedia.org/wiki/Provenance
May 31, 2011

The situation…

 Call to Ontoprise from an insurance company:
„Can you integrate our 5000 databases?“

 EU IP experience (Large Engineering Company):
„oh, we just found another PC that has several tens of
thousands of relevant documents“

 Linked open data cloud


Some of the problems…
 I have this piece of data.
Can I actually believe it?
 Default answer: Find some expert and ask him. 

 I have this inconsistency in my data.
Who has introduced it and why?
 Default answer: Try to find it in the sources. 

 I have this piece of data.
How can I use it? Can I show it to anyone?
 Default answer:
• You are not allowed to do anything with it.
Just throw it away. 

Two Types of Provenance Knowledge

Provenance labels for facts

Which confidence?
Which privileges?
Who?

Bluewater is a City Which
authority?

When?


Two Types of Provenance Knowledge

Provenance labels for facts Open Provenance Model
 RDF graph representing
Which confidence?  Who did
Which privileges? • what
Who? • when
• why
• …
Bluewater is a City Which
authority?  to a data item

1 2 3 4 5
When? admission
exami- asking exami- prepare
nation permit nation share

 „ex post“ workflow instance
 audit/re-enact

SPARQL QUERYING
USING PROVENANCE

R. Dividino, S. Sizov, S. Staab, B. Schüler.
Querying for Provenance, Trust, Uncertainty and other Meta
Knowledge in RDF.
In: Journal of Web Semantics. Elsevier, 7(3), 2009, pp. 204-219.


Representing Provenance Using URIs

http://bluewater.us a dbpedia:city.
http://bluewater.us assertedBy http://neverest.de

BUT:
http://bluewater.us a dbpedia:fakecity.
http://bluewater.us assertedBy http://dpa.de

Who said what?


Representing Provenance Using URIs - 2

http://neverest.de/bluewater a dbpedia:city.
http://neverest.de/bluewater assertedBy
http://neverest.de

http://dpa.de/bluewater owl:sameAs
http://neverest.de/bluewater.
http://dpa.de/bluewater a dbpedia:fakecity.
http:// dpa.de/bluewater assertedBy http://dpa.de

What is the meaning of owl:same as now for
provenance?

Representing Provenance Using Named Graphs
http://dpa.de/ontology
{ dbpedia:locatedIn rdf:domain dbpedia:company.
dbpedia:locatedIn rdf:range dbpedia:city. …. }

http://neverest.de/kb
{ http://bluewater.us a dbpedia:city.
http://vkptv.com a dbpedia:company. }

http://dpa.de/provenance
{ http://dpa.de/ontology dpa:lrm „2000-01-01“.
http://dpa.de/ontology dpa:trust „highest“.
http://neverest.de/kb dpa:lrm „2009-09-09“.
http://neverest.de/kb dpa:trust „lowest“. }

Ambiguity in Representing Provenance
http://neverest.de/kb
{ http://bluewater.us a dbpedia:city.
http://vkptv.com a dbpedia:company. }

What does {…http://neverest.de/kb dpa:trust „lowest“. ..} mean?

Distributive Reading Cumulative Reading
 Each of the two facts is  Taken together the two
assigned low trust facts are assigned low
trust
Both readings are plausible under appropriate circumstances, but
• Cumulative reading is harder to specify
• Cumulative reading requires closing of sets of facts
(contrast to RDF open world semantics)


Meta Knowledge: When?
Meta knowledge dimension
 Set of values plus two operators  and  such that
  and  are partial orders with a maximum
 D D , D D

Least Recently Modified Date
L xsd:dateTime , L Ls.t. Total order,
lrm(a L b) = max(lrm(a), lrm(b))  and  are dual operators
lrm(a L b) = min(lrm(a), lrm(b))


Meta Knowledge: Who?
Meta knowledge dimension
 Set of values plus two operators  and  such that
  and  are partial orders with a maximum
 D D , D D

Provenance
P 2^SOURCES , P Ps.t.
prov(a P b) = prov(a)  prov(b) Partial order
prov(a P b) = prov(a)  prov(b)  and  are same operator


SPARQL: Algebraic Graph Query Languages
[WWW08,
SELECT ?city, ?broadcaster JoWS09]
WHERE {
?city a ex:city.
{ ?broadcaster ex:activeIn ?city }
UNION
{ ?broadcaster ex:locatedIn ?city }
}


[WWW08,
SELECT ?city, ?broadcaster JoWS09]
WHERE {
1
?city a ex:city.
2
UNION
3
} 



2 3 1

SELECT ?city, ?broadcaster [WWW08,
JoWS09]
WHERE {
1 2009-09-09
?city a ex:city.
2 2009-09-09
UNION
3 2009-09-08
} 

|><| max

 min

2 3 1 2009-09-08 2009-09-09 2009-09-09


OWL REASONING
USING PROVENANCE

S. Schenk, R. Dividino, S. Staab.
Ontology Debugging Using Provenance.
In: Journal of Web Semantics, Elsevier, accepted for publication.


Do we trust that bluewater is a real city?

German Press Agency, Neverest,
Highest trust, 2001-01-03 Low trust, 2009-09-09

Explanation (Pinpointing)
Given Ontology O, Axiom , O'  O

O' is an explanation (pinpoint) for  wrt. O, iff
O'  and
O*  for all O*  O'

1

2
Explanation formula
?
3 ( 1  2 ) ( 3  4 )
4


Finding Pinpoints

O‘ O


Computation of meta knowledge for OWL
Query: Meta Knowledge for 

Compute Pinpointing Formula for  wrt O
(A1  …  Am)  …  (Z1  …  Zn)

Insert Meta Knowledge degrees and operators
min(max(lrm(A1), …, lrm(Am)), max(lrm(Z1), …, lrm(Zn))

[KI 2009,
Evaluate SWPM2009]


„Least recently modified?“

(A1  …  Am)  …  (Z1  …  Zn)

min(max(lrm(A1)),…, lrm(Am)),…,max(lrm(Z1),…,lrm(Zn))


Optimization: Syntactic relevance


Optimized Computation of Provenance


9 9 9 9
8
7 7 7 Time
Order
Oracle for you:
relevant pinpoint

5 5

3 Syntactic
Relevance
2 Color codes
2 2
reachability



9 9 9 9
8
7 7 7

5 5

3
2 2 2



9 9 9 9
8
7 7 7
Relevant
pinpoint only
contained
5 5

3
2 2 2

Evaluation: Computing Provenance in Milliseconds

Real-world provenance!


PROVENANCE AWARE
POLICY LANGUAGE


Middle Rhine Hospital

1
admission

Health
Record create

Policies create

Sticky
Log create (P1): ukob is allowed to process health records for research purposes.
However, ukob is not allowed to transfer the health records of patients to
other organizations.

(P2): The mrh demands that the record is only accessed by ukob after
the sharing of the health records is approved by the patient and the
approval must have been confirmed by a doctor.



1 2 3 4 5 6
exami- asking exami- prepare share for
admission
nation permit nation share research

Health
Record create update update de-id. transfer

Policies create update fulfill check
transfer
You

Sticky
Log create update update update update
encrypt transfer

Sticky Log:

step (record, {mrh}, {}, create, patient_treatment, 1, {0})
step (record, {mrh}, {}, update, examination, 2, {1})
reduced (record, hidden, hidden, update, hidden, 4, {2})
step (record, {mrh}, {}, de-identified, privacy, 5, {4})
attribute (record, de-identified, true, 5)
WeST step Steffen Staab {mrh}, {ukob}, transfer, research, 6, {5})
(record, Summer School Semantic Web


1 2 3 4 5 6
admission

Health

transfer
You
permit (6)?
Sticky
Log create (P3): update update update update
permit (ID) IF (step (record, _, _, transfer, _, ID, _) AND
encrypt transfer
attribute (record, de-identified, true, ID)).

Sticky Log:


CONCLUSION


Data Value lies in

Past
 Knowing what happened to your data
 Knowing why it happened to your data

Present
 Drawing the right conclusions from your data

Future
 Deciding upon the destiny of your data

Your Strategy is based on Provenance!
You better take care!

Core References

 W3C working group:
http://www.w3.org/2011/prov/wiki/Main_Page

 IEEE Internet Computing, Vol 15, Issue 1, Jan/Feb 2011
Special Issue on „Provenance in Web Applications“
http://www.computer.org/portal/web/csdl/abs/html/mags/ic/
2011/01/mic2011010017.htm

 Journal of Web Semantics, Volume 9, Issue 2, 2011,
Special Issue on „Provenance in the Semantic Web“
http://www.sciencedirect.com/science/journal/15708268
http://websemanticsjournal.org


Core References of Our Own Work
Provenance in RDF
 R. Dividino, S. Sizov, S. Staab, B. Schüler. Querying for Provenance, Trust,
Uncertainty and other Meta Knowledge in RDF. In: Journal of Web Semantics.
Special issue on "The Web of Data". Elsevier, 7(3), 2009, pp. 204-219.

Provenance in OWL
 S. Schenk, R. Dividino, S. Staab, N. Kurz. Ontology Debugging Using
Provenance. In: Journal of Web Semantics. Special issue on “Ontology
Dynamics“, Elsevier, 9(3), 2011.

Provenance for Policy Languages
 C. Ringelstein, S. Staab. Provenance-aware Policy Definition and Execution. In:
IEEE Internet Computing, special issue on Provenance in Web Applications,
Jan/Feb 2011, pp. 49-58.

Capturing Provenance in Distributed Workflows
 C. Ringelstein, S. Staab. DiALog: A Distributed Model for Capturing Provenance
and Auditing Information. International Journal of Web Services Research
(JWSR), Idea Group Publishing, 7(2): 1-20, 2010.

Thank You!
http://west.uni-koblenz.de

See you again at…


Steffen Staab's Presentation at SSSW 2011

Recommandé

Recommandé

Contenu connexe

Similaire à Steffen Staab's Presentation at SSSW 2011

Similaire à Steffen Staab's Presentation at SSSW 2011 (20)

Dernier

Dernier (20)

Steffen Staab's Presentation at SSSW 2011