  This paper presents a semantic system named OntMed for an ontology-based data
integration of heterogeneous data sources to achieve interoperability between
heterogeneous data sources. Our system is based on the quality criteria
(consistency, completeness and conciseness) for building the reliable analysis
contexts to provide an accurate unified view of data to the end user. The
generation of an error-free global analysis context with the semantic
validation of initial mappings generates accuracy, and provides the means to
access and exchange information in semantically sound manner. In addition, data
integration in this way becomes more practical for dynamic situations and helps
decision maker to work within more consistent and reliable virtual data
warehouse. We also discuss our successful participation in the Ontology
Alignment for Query Answering (OA4QA) track at OAEI 2015 campaign, where our
system (DKP-AOM) has performed fair enough and became one of only matchers
whose alignments allowed answering all the queries of the evaluation.
