There is a comprehensive body of theory studying updates and schema evolution of knowledge bases, ontologies, and in particular of RDFS. In this paper we turn these ideas into practice by presenting a feasible and practical procedure for updating RDFS. Along the lines of ontology evolution, we treat schema and instance updates separately, showing that RDFS instance updates are not only feasible...

The amount of data exposed in the form of RDF and OWL continues to increase exponentially. Some approaches have already been proposed for the scalable reasoning over several language profiles such as RDFS, OWL Horst, OWL 2 EL, OWL 2 RL etc. But all those approaches are limited to the particular ruleset that the reasoner supports. In this work, we propose the idea for a rule-based distributed re...

The problem of updating ontologies has received increased attention in recent years. In the approaches proposed so far, either the update language is restricted to sets of ground atoms or, where the full SPARQL update language is allowed, the TBox language is restricted so that no inconsistencies can arise. In this paper we discuss directions to overcome these limitations. Starting from a DL-Li...

We survey nearly 1300 OWL ontologies and RDFS schemas. The collection of statistical data allows us to perform analysis and report some trends. Though most of the documents are syntactically OWL Full, very few stay in OWL Full when they are syntactically patched by adding type triples. We also report the frequency of occurrences of OWL language constructs and the shape of class hierarchies in t...

This paper presents the results of an industrial project, conducted by the TecGraf Institute and Petrobras (the Brazilian Petroleum Company), to develop a tool to facilitate access to a large database, with hydrocarbon exploration data, by combining RDF technology with keyword search. The tool features an algorithm to translate a keyword query into a SPARQL query such that each result of the SP...

Ontology is used to annotate sensor network data and enhances its semantic, which is the motivation of Semantic Sensor Network (SSN). With the development of SSN, massive RDF datasets have been produced, so SSN is up against a big challenge now, i.e., the integration and application of data. In this paper, we present a Hadoop-based Semantic Sensor Network System (named HDSW) to achieve efficien...

Ontologies define hierarchies of classes and attributes; they are meta-data: data about data. XML Schema and RDF Schema are both (lightweight) ontology definition languages in that sense. In the “traditional” approach to ontology engineering, experts add new data by carefully analyzing others’ ontologies and fitting their new concepts into the existing hierarchy. In the emerging “Semantic Web” ...

The web of data consists of distributed, diverse (in terms of schema adopted), and large RDF datasets. In this paper we present a SPARQL query rewriting method which can be used to achieve interoperability in semantic information retrieval and/or knowledge discovery processes over interconnected RDF data sources. Formal mappings between different overlapping ontologies are exploited in order to...

Aside from crawling, indexing, and querying RDF data centrally, Linked Data principlesallow for processing SPARQL queries on-the-fly by dereferencing URIs. Proposed link-traversalquery approaches for Linked Data have the benefits of up-to-date results and decentralised (i.e.,client-side) execution, but operate on incomplete knowledge available in dereferenced documents,thus affe...

Given the explosive growth in both data size and schema complexity, data sources are becoming increasingly difficult to use and comprehend. Summarization aspires to produce an abridged version of the original data source highlighting its most representative concepts. In this paper, we present an advanced version of the RDF Digest, a novel platform that automatically produces and visualizes high...