corner: a completeness reasoner for sparql queries over rdf data sources

CORNER:A Completeness Reasoner for the Semantic Web1

Fariz Darari

Radityo Eko PrasojoWerner Nutt

EPCL Workshop 2014, Dresden

1to be demonstrated at ESWC 2014Fariz Darari (EPCL Workshop 2014) CORNER 1 / 14

Introduction

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Introduction

Completeness statement about the IMDB data source

Quentin Tarantinowas the character

Mr. Brown

…………………………

……………

http://www.imdb.com/title/tt0105236/fullcredits?ref_=tt_ov_st_sm#cast

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Introduction

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Introduction

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Motivations

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Motivations

Darari et al.2 developed a logical framework forcompleteness reasoning techniques on the SWThe framework enables creation of descriptions as to whichparts of a data source are complete, called completenessstatementsChecks whether a query returns a complete result, calledquery completeness checks, are then possible

2Fariz Darari, Werner Nutt, Giuseppe Pirró, Simon Razniewski:Completeness Statements about RDF Data Sources and Their Use for QueryAnswering. ISWC 2013Fariz Darari (EPCL Workshop 2014) CORNER 7 / 14

Motivations

However, implementation is still missingWe built an implementation of the framework, calledCORNER

A Web-based demo can be accessed athttp://corner.inf.unibz.it/

Implementation reused the Apache Jena (Semantic Weblibrary) and Google Web Toolkit (User Interface library)

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System Architecture

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System Architecture

Completeness reasoning steps:From the query Q, CORNER generates an initial graph Gi

Qrepresenting the information needed for answering thequeryEvery completeness statement C is translated into aSPARQL CONSTRUCT query QC

Application of all the queries QC to the graph GiQ results in a

subgraph GaQ of Gi

Q, representing parts of the query forwhich data are completeBy evaluating Q over Ga

Q, CORNER tests whether thecomplete data are sufficient to answer Q

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Demo

DEMO

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Bonus: CANDy

CANDy = Completeness-Aware Querying and Navigationon the Web of DataGoals:

To develop techniques to leverage meta-information aboutthe completeness of data sources for navigation andqueryingTo reconcile the two paradigms of open- and closed-worldsemantics underlying RDF and SPARQL, respectively

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CANDy: Techniques for completenessreasoning

Research in progress:Queries and completeness statements with comparisonsQuantitative completeness reasoningCompleteness reasoning in the domain of streamprocessingCompleteness statements mining from the Web

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CANDy: Reconciling the open- and closedworld semantics

Research in progress:Correctness and completeness of non-monotonic queriesUNA vs non-UNA paradigms on completeness reasoning

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