Konstantin Todorov

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Due to the high heterogeneity of ontologies, a combination of many methods is necessary in order to discover correctly the semantic correspondences between their elements. An ontology matching tool can be seen as a collection of several matching components, each implementing a specific method dealing with a specific heterogeneity type (terminological,(More)
The linguistic description, i.e. semantic annotation of images can benefit from representations of useful concepts and the links between them as ontologies. Recently, several multimedia ontologies have been proposed in the literature as suitable knowledge models to bridge the well known semantic gap between low level features of image content and its high(More)
Ontologies describe the semantics of data and provide a uniform framework of understanding between different parties. The main common reference to an ontology definition describes them as knowledge bodies, which bring a formal representation of a shared conceptualization of a domain – the objects, concepts and other entities that are assumed to exist in a(More)
The paper presents an overview of a novel procedure for mapping hierarchical ontologies, populated with properly classified text documents. It combines structural and instance-based approaches to reduce the terminological and conceptual ontology heterogeneity. It yields important granularity and instantiation judgments about the inputs and is to be applied(More)
We consider the problem of discovering pairs of similar concepts, which are part of two given source ontologies, in which each concept node is mapped to a set of instances. The similarity measures we propose are based on learning a classifier for each concept that allows to discriminate the respective concept from the remaining concepts in the same(More)
Instance-based ontology mapping comprises a collection of theoretical approaches and applications for identifying the implicit semantic similarities between two ontologies on the basis of the instances that populate their concepts. The current paper situates this general problem in the realm of finding mappings between the nodes of two different web(More)
The paper builds on a previous finding of the same authors that concept similarity can be measured on the basis of small sets of characteristic features, selected separately and independently for every concept of two source ontologies. Extending a previously defined parameter-dependent similarity measure, the paper suggests the application of parameter-free(More)