A wide range of problems can be modelled as constraint satisfaction prob- lems (CSPs), that is, a set of constraints that must be satisfied simultaneously.
Erich Novak, Ian H. Sloan and Henryk Wozniakowski. April 1997 ...... [6] J. F. Traub, G. W. Wasilkowski, and H. Wozniakowski, Information-based Complexity,.
The second way that one can view parameterized complexity is as a ..... Rock the range of k. Increasingly viable. Figure 1. The view from Mars: interesting ...... Castle, Czech Republic, June, 1997, F. Roberts, J. Kratochvil and J. Ne set ril (eds.),
Stdev (n=3). Specific. Binding (fmols /mg protein). 0.32. 0.006. DoE Input Conditions. Mean specific radio-ligand binding activity with. 3[H]ZM241385 antagonist.
Universite du Quebec a Montreal. C.P. 8888 ... Abstract. We present a theory of grammar based on asymmetrical relations, the Strict Asym- .... mainly English and in Romance (Italian and French) as well as in non Indo-European languages,.
Digital Enterprise Research Institute www.deri.ie. Linked Data. â« Uses the Web infrastructure and standards to expose and interlink datasets. â« Linked Data ...
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A Multidimensional Semantic Space for Data Model Independent Queries over RDF Data André Freitas, João Gabriel Oliveira, Edward Curry Seán O’Riain
Copyright 2009 Digital Enterprise Research Institute. All rights reserved.
Outline Digital Enterprise Research Institute
Problem Space & Motivation Description of the Approach Evaluation Conclusion & Future Work
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Linked Data Digital Enterprise Research Institute
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Uses the Web infrastructure and standards to expose and interlink datasets. Linked Data vision: The
Web
Web as a single Dataspace. of interlinked datasets.
Linked Data: Adoption Digital Enterprise Research Institute
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Queries over Linked Data Digital Enterprise Research Institute
Linked Data brings a consumption:
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fundamental challenge for data
How to query heterogeneous and distributed datasets?
At Web scale it is unfeasible for end-users to be aware of the location and structure of datasets.
Demand for new query mechanisms for Linked Data (data model independency).
Query/Search Spectrum Digital Enterprise Research Institute
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Adapted from Kauffman et al (2009)
Fundamental Problem Digital Enterprise Research Institute
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From which university did the wife of Barack Obama graduate?
Popescu (2003): Semantic tractability problem.
Semantic Matching Problem Digital Enterprise Research Institute
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From which university did the wife of Barack Obama graduate?
Semantic Matching Problem Digital Enterprise Research Institute
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From which university did the wife of Barack Obama graduate?
Entity identification
Semantic Matching Problem Digital Enterprise Research Institute
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From which university did the wife of Barack Obama graduate?
Entity search
Semantic Matching Problem Digital Enterprise Research Institute
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From which university did the wife of Barack Obama graduate?
Approximate semantic matching
Semantic Matching Problem Digital Enterprise Research Institute
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From which university did the wife of Barack Obama graduate?
Approximate semantic matching
Semantic Matching Problem Digital Enterprise Research Institute
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From which university did the wife of Barack Obama graduate?
Approximate semantic matching
Semantic Matching Problem Digital Enterprise Research Institute
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From which university did the wife of Barack Obama graduate?
Structural matching
Semantic Matching Problem Digital Enterprise Research Institute
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From which university did the wife of Barack Obama graduate?
T- Space
Strategy Digital Enterprise Research Institute
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Best-effort query model (ranked results). Use of a distributional semantic model. Two phase search process combining entity search with spreading activation search.
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Proposed Approach
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Query Approach Rationale Digital Enterprise Research Institute
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Query Approach Rationale Digital Enterprise Research Institute
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Query Approach Rationale Digital Enterprise Research Institute
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Query Approach Rationale Digital Enterprise Research Institute
Final Query- Data Matching:
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Semantic Relatedness Digital Enterprise Research Institute
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Computation of a measure of “semantic proximity” between two terms. Allows a semantic approximate matching between query terms and dataset terms.
Most existing approaches use WordNet-based solutions for approximate semantic matching. Distributional semantic approaches address these limitations.
Distributional Semantics Digital Enterprise Research Institute
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Assumption: the context surrounding a given word in a text provides important information about its meaning. Meaning is mediated by word distribution in the corpora. Simplified semantic model.
Opera is an art form in which singers and musicians perform a dramatic work combining text (called a libretto) and musical score. Opera is part of the Western classical music tradition. Opera incorporates many of the elements of spoken theatre, such as acting, scenery, and costumes and sometimes includes dance. The performance is typically given in an opera house, accompanied by an orchestra or smaller musical ensemble.
Explicit Semantic Analysis (ESA) Digital Enterprise Research Institute
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Based on Wikipedia. Interpretation vector using Wikipedia articles titles.
Building the T- Space (Steps) Digital Enterprise Research Institute
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Building the distributional semantic model using ESA. Construction of instances spaces (TF/IDF). Construction of classes spaces (ESA). Construction of relation spaces (ESA).
Building the T- Space Digital Enterprise Research Institute
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relations
instances
properties classes
Building the T- Space Digital Enterprise Research Institute
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Instances Digital Enterprise Research Institute
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Building the T- Space Digital Enterprise Research Institute
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Classes Digital Enterprise Research Institute
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Universal ESA Space
Building the T- Space Digital Enterprise Research Institute
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Relations Digital Enterprise Research Institute
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Universal ESA Space
Building the T- Space Digital Enterprise Research Institute
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Querying the T- Space Digital Enterprise Research Institute
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Querying the T- Space Digital Enterprise Research Institute
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Querying the T- Space Digital Enterprise Research Institute
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Querying the T- Space Digital Enterprise Research Institute
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Digital Enterprise Research Institute
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Treo (Irish): Route, path
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Evaluation
Quality of Results Digital Enterprise Research Institute
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QALD DBPedia Training Set. 50 natural language queries. DBpedia 3.6. Full DBPedia QuerySet (50 queries) Avg. Precision
Error Distribution Digital Enterprise Research Institute
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Conclusion & Future Work Digital Enterprise Research Institute
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The T-Space semantic model shows a promising direction for providing data model independent queries over RDF data. Improvement of semantic tractability. The distributional semantic model supports a flexible matching between query terms and dataset terms in a besteffort scenario. Further improvements are needed:
QA features (e.g. answer type detection, operators). User feedback mechanisms (disambiguation). Entity recognition for complex classes.
