Gregory Karvounarakis

Publications
Influence

T. Green, Gregory Karvounarakis, V. Tannen
Mathematics, Computer Science
PODS '07
11 June 2007

We show that relational algebra calculations for incomplete databases, probabilistic databases, bag semantics and why-provenance are particular cases of the same general algorithms involving semirings. Expand

RQL: a declarative query language for RDF

Gregory Karvounarakis, S. Alexaki, V. Christophides, D. Plexousakis, M. Scholl
Computer Science
WWW '02
7 May 2002

We propose a new RDF query language called RQL that enables to uniformly query both resource descriptions and schemas by means of RDF schemas. Expand

The ICS-FORTH RDFSuite: Managing Voluminous RDF Description Bases

S. Alexaki, V. Christophides, Gregory Karvounarakis, D. Plexousakis, K. Tolle
Computer Science
SemWeb
1 May 2001

We present RDFSuite, a suite of tools for RDF validation, storage and querying. Expand

Update Exchange with Mappings and Provenance

T. Green, Gregory Karvounarakis, Z. Ives, V. Tannen
Computer Science
VLDB
23 September 2007

We consider systems for data sharing among heterogeneous peers related by a network of schema mappings. Expand

Benchmarking Database Representations of RDF/S Stores

Yannis Theoharis, V. Christophides, Gregory Karvounarakis
Computer Science
International Semantic Web Conference
6 November 2005

In this paper we benchmark three popular database representations of RDF/S schemata and data: (a) a schema-aware (i.e., one table per Rdf/S class or property) with explicit (ISA) or implicit (NOISA) storage of subsumption relationships, using (ID) or not (URI) identifiers to represent resources and (c) a hybrid of the schema- aware and schema-oblivious representations. Expand

Querying the Semantic Web with RQL

Gregory Karvounarakis, Aimilia Magkanaraki, +4 authors K. Tolle
Computer Science
Comput. Networks
5 August 2003

We propose RQL, a new query language adapting the functionality of semistructured or XML query languages to the peculiarities of RDF but also extending this functionality in order to uniformly query both RDF descriptions and schemas. Expand

LogicBlox, Platform and Language: A Tutorial

T. Green, M. Aref, Gregory Karvounarakis
Computer Science
Datalog
11 September 2012

The modern enterprise software stack--a collection of applications supporting bookkeeping, analytics, planning, and forecasting for enterprise data--is in danger of collapsing under its own weight. Expand

ORCHESTRA: facilitating collaborative data sharing

T. Green, Gregory Karvounarakis, N. J. Taylor, Olivier Biton, Z. Ives, V. Tannen
Computer Science
SIGMOD '07
11 June 2007

We propose a model for a declarative, yet extremely flexible, approach to data sharing, called the collaborative data sharing system, or CDSS. Expand

The RDFSuite: Managing Voluminous RDF Description Bases

S. Alexaki, V. Christophides, Gregory Karvounarakis
Computer Science
2000

In this paper, we advocate the use of database technology to support declarative access, as well as, logical and physical independence for voluminous RDF description bases. Expand

Optimizing taxonomic semantic web queries using labeling schemes

V. Christophides, Gregory Karvounarakis, D. Plexousakis, M. Scholl, Sotirios Tourtounis
Computer Science
J. Web Semant.
1 February 2004

We advocate for the use of labeling schemes for modeling these hierarchies in order to efficiently answer queries such as subsumption check, descendants, ancestors or nearest common ancestor, which usually require costly transitive closure computations. Expand

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