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Extensions of Semantic web modeling towards ordering of
query results
J. Pokorný (Charles University, Prague), P. Vojtáš (Šafárik University, Košice)
Vienna June 20th, 2005 W3C and Semantic Web 2
Motivation – user looking for best (top-k) objects
Same data – different problems and solutions - Kossmann’s skylines - Fagin’s threshold algorithm - fuzzy logic programming
Learning of user’s aggregation function @
DL: Value or existential restrictions
Fuzzy Description logic EL with @
Page Content Rank
Galois - Tukey connections – Questions and Answers
Conclusions
Outline
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 3
Skyline of hotels: minimize price (x-axis) and distance to beach (y-axis)
Skyline of buildings
D. Kossmann et al. - Institute for Information Systems - DCS ETH Zurich
Find a good hotel
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 4
Access multimedia data – red – inherently fuzzy
Compound queries – red and round – aggregate
NY restaurant – good, inexpensive, close
- Zagat-Review web site gives rating
- NYT web site gives prices
- MapQuest gives distances … aggregate
Relevant answers wrt users intention – best, top-k
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
R. Fagin. Combining fuzzy information: an Overview. SIGMOD Record 31,2002Güntzer et al. Optimizing Multi-Feature Queries for Image Databases, VLDB’00
Fuzzy …
Vienna June 20th, 2005 W3C and Semantic Web 5
xx*
@
xx
*@
xx /
4
*3@ 1 closecheapuser
hotelgood
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Combining fuzzy…
Vienna June 20th, 2005 W3C and Semantic Web 6
21,@ BBH
Continuity, fixpoint, completeness, similarity,
PV. Fuzzy logic programming. Fuzzy Sets and Systems. 124,3 (2001) 361-370
LPrbCH
rBHbBDB
I
)),(,(
),(),,(
BH BH Need not be equivalent to
Our solution
1BH
2BH Disjunction or aggregation?
Logic programming in extensional fuzzy logic in narrow sense
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 7
Resource Representation
Hotel, restaurant, product, service,… Object - attributeMultimedia, pictures,… color spectra, texture,…Texts vector, dependency tree,….
User QueryContext, classification, preference ideal object, text, …. Models - what is the bestDatabases - small, medium, large model-proof theoretic semanticsMetric - closer is betterVectors - smaler angle is betterBayes - more probable is betterMulticriterial decisionPrice function - optimizationFuzzy logic - comparative notion of truth – higher TV is better - semantics
Same data – different problems – different solutions
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 8
Deduction
Abduction
Induction
Learning how to combine particular attribute score Into global score FILP
Other inductive methods – on same data??
ObservatExplanatB
ExampleHypothesisB
Declarative query languages
ExampleHypothesisB /
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 9
Gradually classified data – input for learning – synthetic data
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 10
Add to background knowledge
p(d) ← d<c & p(c)
Graded ILP problem formulation
• E(e1) < E(e2) THEN fm (e1) ≤ fm (e2) and• E(e1) > E(e2) THEN fm (e1) ≥ fm (e2)
P. Vojtáš, T. Horváth, S. Krajči, R. Lencses. An ILP model for a monotone graded classification problem. Kybernetika 40,3 (2004) 317-332
Learning with qualitative constraint – monotonicity and the problem formulation
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 11
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
The aggregation function
Vienna June 20th, 2005 W3C and Semantic Web 12
Unicode
RDF + RDFSchema
ontology
logic
proof
URI
XML + name spaces + XMLSchema
optimisation
security
trust
Semantic web according to Tim Berners-Lee et al
Machine processing
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 13
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
F. Baader, S. Brandt, C. Lutz. Pushing the EL Envelope, 2005
Description logic FL0 …allows for value restriction ∀r.C…when clarifying the logical status of property arcs in semantic networks and slots in frames
– the decision was taken –
that arcs/slots should be read as value restrictions rather than existential restrictions ∃r.C
tractability turned out to be unattainable
DL – value or existential restriction
Vienna June 20th, 2005 W3C and Semantic Web 14
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
F. Baader, S. Brandt, C. Lutz. Pushing the EL Envelope, 2005
Recently, the choice of value restriction as a sine qua non of DL has been reconsidered…EL – allowing conjunction and existential restrictions…Better algorithmic properties
In applications the expressive power of EL sufficient
DL – value or existential restriction
Vienna June 20th, 2005 W3C and Semantic Web 15
good hotel
neither ∃ price.cheap distance.close⊓ ∃ nor ∃ price.cheap ⊔ distance.close∃
We need an extension
@( price.cheap, distance.close)∃ ∃
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Fuzzy EL Description logic with @
Vienna June 20th, 2005 W3C and Semantic Web 16
PAGE CONTENT RANK
categories of Web data mining (Pal et al, 2002): • Web Structure Mining (WSM), • Web Usage Mining (WUM),• Web Content Mining (WCM).
Here: WCM refers broadly to the process of uncovering interesting and potentially useful knowledge from web contents/documents
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 17
The PCR method in sketch
Principle: PCR enables to classify pages from a set Rq of pages retrieved as the result of a conjunctive Boolean query q.
Relevance measure computation:– vector models: comparing the query vector with the page
vector– here: it is derived only from importances of terms that the page
containsThe core of PCR is based on an evaluation of terms from Rq according
to their occurrences in pages and their semantic properties. Final term evaluation is calculated from the parameters gained by an adapted backpropagation neural network.
A set of training examples (terms) is obtained from the set Rq0, where q0 is a starting query. The relevance of the terms to the given topic has been assigned manually.
Pokorný, Smižanský. IASTED AC 2005
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 18
PCR Concluded
To validate the hypothesis• PCR identifies pages which are more significant with
respect to their content and better explains given topic than the PageRank algorithm.
we need more experiments.Issues: time complexity of obtaining Rq,n
Solution: PCR module on the side of the search engine Development: • ranking clusters• continuous adaptability of the system depending on
user reactions • more semantics - phrases
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 19
Galois Tukey connections
P. Vojtáš. Gen. Galois-Tukey connections Israel Math.Conf.Proc. 6 (1993) 619-643A. Blass. Questions and answers, Proc. Linear Logic, J.Y. Girard, LMSLN 222, 1995
Questions1
Questions2
Answers1
Answers2
Correct1wrt KB1
Correct2wrt KB2
f(q1) Correct2 a2 then q1 Correct1 g(a2)
f g
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 20
Questions1
Questions2
Answers1
Answers2
_Correct1_
_Correct2_
(h(q1) C3 a3) and (f(q1,a3) Correct2 a2) then q1 Correct1 g(a2)
Q3 _C3_ A3
h
f
g
Galois-Tukey connections, iterated forcing and querying with advice
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Vienna June 20th, 2005 W3C and Semantic Web 21
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
Marie-Christine Rousset: Small can be beautiful in the semantic web, ISWC 2004
We need modeling tools for- Ordering of results- Aggregation of particular attribute score into global
Conclusions
Optimisation Proof Logic Ontology RDF + RDFSXML … User dependent
Vienna June 20th, 2005 W3C and Semantic Web 22
Thank you
J. Pokorný, P. Vojtáš. Extensions of Semantic web modeling towards ordering of query results
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