One of the main limitations in using ontologies in modern information systems is due to the fact that the design and maintenance of ontologies is a complex activity that requires a specific background in formal logics and data semantics. In this paper, we present the iCoord coordination system, which aims at supporting content managers and domain experts in the process of defining and maintaining domain ontologies. In particular, we describe the natural language explanation tool (NLE) of iCoord for ontology knowledge authoring.

A huge amount of schemas are expressed within outdated schema languages which are restricted concerning expressiveness, extensibility, readability, and understandability. Consequently, the actual intention of the schema developers is hard to grasp. Reverse engineering approaches try to tackle this problem by automatically transforming legacy schemas into ontologies, but rarely enhance the semantics of the schemas by exploiting the higher expressiveness of modern schema languages.

Therefore, we propose a meta-framework for generating ontologies from legacy schemas going beyond existing approaches. This meta-framework is instantiable for various schema reverse engineering scenarios and allows to generate ontologies with improved structures and semantics compared to the original legacy schemas by exploiting the advanced expressiveness of modern schema languages. Finally, this meta-framework allows for the automatic migration of data from the legacy schemas into instances of the generated ontologies.

Graph visualization is one of the popular ways to present RDF data. But all practical RDF visualizers have to somehow deal with the problem of the size of the data. Not only can the total number of triples in RDF data be very large, but even degrees of the nodes of the graph can be very high. This article discusses some problems and solution related to visualization and exploration of such data, usually in relation to the RDF node merging technique.

In this paper, we present a new language for XML integrity constraints. In contrast to other languages for XML integrity constraints, we propose to specify constraints at the conceptual level independently of technical details of a respective XML format. This brings several advantages. The constraint expressions are easier to specify and understand and they are also more resistant to changes in the XML format. We also show how a conceptual expression can be translated to an equivalent expression at the logical XML level using XPath which can be used for validating XML documents.

In this paper, we present a tool called X2OWL that aims at building an OWL ontology from an XML data source. This method is based on XML schema to automatically generate the ontology structure, as well as, a set of mapping bridges. The presented method also includes a refinement step that allows to clean the mapping bridges and possibly to restructure the generated ontology.

This paper presents algorithmic approaches for the transformation of list based search results from a semantic search engines (i.e. SemSearch) into a visual representation. We present the results and methodology of our preliminary implementation of the semantic search visualization engine (ViSS). ViSS, takes as input the semantic structure of semantic search results and reproduces them into a summarized, conclusive and meaningful graphical representation. Depending on the semantic search results our algorithms select the best visual representations. The current version of ViSS supports visual formats of directed graphs, charts and tables.