Benjamin Cogrel

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In this paper we present Ontop, an open-source Ontology Based Data Access (OBDA) system that allows for querying relational data sources through a conceptual representation of the domain of interest, provided in terms of an ontology, to which the data sources are mapped. Key features of Ontop are its solid theoretical foundations, a virtual approach to OBDA(More)
The database landscape has been significantly diversified during the last decade, resulting in the emergence of a variety of non-relational (also called NoSQL) databases, e.g., XML and JSON-document databases, key-value stores, and graph databases. To facilitate access to such databases and to enable data integration of non-relational data sources, we(More)
A significant number of database architectures and data models have been proposed during the last decade. While some of these new systems have gained in popularity, their formal semantics are generally still missing. In this paper, we consider the symptomatic case of MongoDB, a widely adopted document database, in which roughly speaking relational tables(More)
Ontop is an Ontology Based Data Access system allowing users to access a relational database through a conceptual layer provided by an ontology. In this demo, we use the recently developed NPD benchmark (+4 billion triples) to demonstrate the features of Ontop . First we use Ontop as a SPARQL end-point to load the ontology and mappings, and answer SPARQL(More)
Ontology-based data access (OBDA) has become a popular paradigm for accessing data stored in legacy sources using Semantic Web technologies. In the OBDA setting, users access the data through a conceptual layer, which provides a convenient query vocabulary abstracting from specific aspects related to the data sources. This conceptual layer is typically(More)
Context has a crucial importance in the way actions are perceived and done, especially in ubiquitous robotics where context is rich and subject to substantial variations. Given that service selection focuses on the nonfunctional performance of services, it must be tightly related to the context. Unfortunately, as far as we know, previous works have not(More)
The database landscape has been significantly diversified during the last decade, resulting in the emergence of a variety of non-relational (also called NoSQL) databases, e.g., XML and JSON-document databases, key-value stores, and graph databases. To facilitate access to such databases and to enable data integration of non-relational data sources, we(More)
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