Bienvenue dans le cours d'optique ondulatoire de L2, année 2022-2023.

Today, we are experiencing an unprecedented production of resources, published as Linked Open Data (LOD, for short). This is leading to the creation of knowledge graphs (KGs) containing billions of RDF (Resource Description Framework) triples, such as DBpedia, YAGO and Wikidata on the academic side, and the Google Knowledge Graph or eBay Knowledge Graph on the commercial side. They contain knowledge that is typically expressed in RDF, i.e., as statements of the form . Sometimes, the various types and relations are represented in an OWL2 (Web Ontology Language) ontology, which defines their interrelations and axioms such as, subsumption, disjunction and functionality of properties. 

However, the existing KGs are far from being complete and consistant. Hence, different methods are needed to be developed on top of these existing KGs. In one hand, methods that aim to expanding and enriching KGs, in the other hand, methods addressing the problem of validating the content of the KGs. In this course we will focus on the identity problem which consists in finding and validating identity links between resources and knowledge discovery problem (e.g. key axioms, logical rules) from RDF data. This course will also reserve place to some feedback from applications using knowledge graphs and ontologies such as bio-informatics, agronomy and IoT.