Ontop: answering SPARQL queries over relational databases

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, which avoids materializing triples and is implemented through the query rewriting technique, extensive optimizations exploiting all elements of the OBDA architecture, its compliance to all relevant W3C recommendations (including SPARQL queries, R2RML mappings, and OWL2QL and RDFS ontologies), and its support for all major relational databases

The virtual knowledge graph system Ontop

Ontop is a popular open-source virtual knowledge graph system that can expose heterogeneous data sources as a unified knowledge graph. Ontop has been widely used in a variety of research and industrial projects. In this paper, we describe the challenges, design choices, new features of the latest release of Ontop v4, summarizing the development efforts of the last 4 years

Impact-based Contextual Service Selection in a Ubiquitous Robotic Environment

International audienceno abstrac

Efficient handling of SPARQL OPTIONAL for OBDA (Extended Version)

OPTIONAL is a key feature in SPARQL for dealing with missing information. While this operator is used extensively, it is also known for its complexity, which can make efficient evaluation of queries with OPTIONAL challenging. We tackle this problem in the Ontology-Based Data Access (OBDA) setting, where the data is stored in a SQL relational database and exposed as a virtual RDF graph by means of an R2RML mapping. We start with a succinct translation of a SPARQL fragment into SQL. It fully respects bag semantics and three-valued logic and relies on the extensive use of the LEFT JOIN operator and COALESCE function. We then propose optimisation techniques for reducing the size and improving the structure of generated SQL queries. Our optimisations capture interactions between JOIN, LEFT JOIN, COALESCE and integrity constraints such as attribute nullability, uniqueness and foreign key constraints. Finally, we empirically verify effectiveness of our techniques on the BSBM OBDA benchmark

Sélection de services basée sur l'impact en environnement ubiquitaire

International audienceno abstrac

Isotrétinoïne : quelles actualités en dermatologie ? Conclusions du séminaire Centre de preuves en dermatologie et groupe DEFI de la SFD

National audienceContextIn November 2021, the French National Medicines Agency (ANSM – Agence nationale de sécurité des médicaments) asked the French Society of Dermatology (SFD) to examine current isotretinoin use in France.MethodsTo answer the questions raised by the ANSM, a seminar was organized by the Centre of Evidence (CDP) of the SFD in June 2022 involving a multidisciplinary panel of French experts (including members of the CDP, health professionals and patient association leader). After a short presentation of each question by one or more experts, a number of proposed solutions and clinical and translational research projects were discussed.ResultsThe main points concerned the use of the Adolescent Depression Rating Scale score before and during isotretinoin treatment for acne to evaluate the risk of depression and the need to reinforce information to patients concerning prevention of pregnancy. Reducing the frequency of laboratory monitoring was also proposed. Off-label uses for other indications (first-line therapy for certain types of acne on pigmented skin, adult acne, rosacea, seborrheic dermatitis, hidradenitis suppurativa, etc.) were specified with proposals for research projects. Finally, the need for improving both communication tools (health professionals and patients/parents) and the care pathway was highlighted. The development of continuing medical education for health professionals and updating recommendations were proposed and will be supported by the French DErmatoses FacIales group of the SFD.ContexteEn novembre 2021, l’Agence nationale de sécurité des médicaments (ANSM) a sollicité la Société française de dermatologie (SFD) sur les modalités actuelles d’utilisation de l’isotrétinoïne en France.MéthodesPour répondre aux interrogations soulevées par l’ANSM, un séminaire a été organisé par le Centre de preuves (CDP) de la SFD en juin 2022, réunissant les membres du CDP et des experts (professionnels de santé, représentant de patient). Après un état des lieux pour chaque question par un ou plusieurs experts, un temps de discussion était dédié à la formulation de solutions et de projets de recherche clinique et translationnelle.RésultatsLes principales propositions concernaient l’utilisation du score ADRS (Adolescent Depression Rating Scale) lors de l’introduction et du renouvellement de l’isotrétinoïne dans l’acné pour identifier les patients à risque psychiatrique et la nécessité d’un renforcement de l’information sur la prévention des grossesses. Un allègement de la surveillance biologique est également proposé. Les modalités d’utilisation hors AMM pour d’autres indications (1re ligne dans certaines acnés sur peaux noires et pigmentées, acné du bas du visage de la femme adulte, rosacée, dermatite séborrhéique, hidradénite suppurée, etc.) ont été précisées avec des propositions de projets de recherche. Enfin, une amélioration des outils de communication (professionnels de santé et patients/parents) et du parcours de soins est nécessaire. Le développement de la formation continue pour les professionnels de santé et l’actualisation des recommandations ont été proposés et seront portés par le nouveau groupe thématique DEFI (DErmatoses FacIales) de la SFD