DSpace JSPUI

SQL:2011, the most recently adopted version of the SQL query language, has unprecedentedly standardized the representation of temporal data in relational databases. Following the successful paradigm of ontology-based data access, we develop a practical approach to querying the SQL:2011-based temporal data model via the semantic layer of OWL 2 QL. The interval-based temporal query language (TQL), which we propose for this task, is based on naturally characterizable combinations of temporal log...

Linked Data seem to play a seminal role in the establishment of the Semantic Web as the next-generation Web. This is even more important for digital object collections and educational institutions that aim not only to promote and disseminate their content but also to aid its discoverability and contextualization. Having already ‘semantified’ a popular digital repository system, DSpace, in this paper we show how repository metadata can be exposed as Linked Data, thus enhancing their machine un...

The visualization of ontologies is a challenging task especially if they are large. We will demonstrate StarLion, a system providing exploratory visualizations which enhance the user understanding. StarLion combines many of the existing visualization methods with some novel features for providing better 2D layouts. Specifically, one distinctive feature of StarLion is the provision of Star-like graphs of variable radius whose layout is derived by a Force Directed Placement algorithm (FDPA) spe...

In this demo we present RDFauthor, an approach for authoring information that adheres to the RDF data model. RDFauthor completely hides syntax as well as RDF and ontology data model difficulties from end users and allows to edit information on arbitrary RDFa-annotated web pages. RDFauthor is based on extracting RDF triples from RDFa-annoted Web pages and transforming the RDFa-annotated HTML view into an editable form by using a set of authoring widgets. As a result, every RDFa-annotated web p...

There are many interesting Knowledge Representation questions surrounding rule languages for the Semantic Web. The most basic one is of course: which kind of rules should be used and how do they integrate with existing Description Logics? Similar questions have already been addressed in the field of Logic Programming, where one particular answer has been provided by the language of FO(ID). FO(ID) is an extension of first-order logic with a rule-based representation for inductive definitions. ...

Open Answer Set Programming (OASP) is an attractive framework for integrating ontologies and rules. Although several decidable fragments of OASP have been identified, few reasoning procedures exist. In this paper, we provide a sound, complete, and terminating algorithm for satisfiability checking w.r.t. forest logic programs, a fragment where rules have a tree shape and allow for inequality atoms and constants. We further introduce f-hybrid knowledge bases, a hybrid framework where SHOQ know...

Biodiversity management requires the usage of heterogeneous biological information from multiple sources. Indexing, aggregating, and finding such information is based on names and taxonomic knowledge of organisms. However, taxonomies change in time due to new scientific findings, opinions of authorities, and changes in our conception about life forms. Furthermore, organism names and their meaning change in time, different authorities use different scientific names for the same taxon in diffe...

GameDipper is a similar video game finding mashup. It is based on reviews written about video games. Because game reviews usually describe video graphic, game play, virtual world, possibilities of character and compare current game with similar ones, GameDipper extracts mentioned facts and bases video game similarity on them. GameDipper's database contains about 20 thousands of different video games with more than 26 thousands video game reviews. It provides simple web interface and 2 search ...

As opposed to existing keyword suggestion systems (such as AdWords Keyword Tool) that suggest keywords based on co-occurrence in searchers, in texts etc. we propose a system that uses DBPedia to help the user discover (potentially unknown) relevant keywords. Our system thus suggests keywords based on their meaning, and conceptual relations, rather then based on co-occurring use of the keywords. Our approach consists of (1) finding the DBPedia concepts that are directly referred to in the user...

Sztakipedia is a tool for creating and editing semantically annotated content. Sztakipedia supports the composition of Wikipedia articles with internal and external link-, category-, and infobox (type-) recommendations.The interface is a rich text editor, which sends the content written by the user to a servlet, which in turn sends it to UIMA Annotation Engines and other external services. Then the results are aggregated and suggestions are sent back to the user interface. If the user accepts...

We propose the use of Social Awareness Streams(e.g.Facebook) for characterising evolving features of Points of Interest (POIs), from the point of view of (human) end users. We present the Topica application which provides a view on the collective perception of POIs. The application is divided in two stages: (1) The Linked Data representation of POIs, and the (2) visualisation of POIs. The first stage mashes up services from OpenCalais, Zemanta and DBPedia Spotlight for entity enrichment; the ...

Semantic Web and Web 2.0, are gradually seen as complementary visions for the future evolution of the Web. Semantic Web technologies have been considered as a bridge for the technological evolution from Web 2.0 to Web 3.0, the Web about recommendation and personalization. Towards this perspective, in this work we introduce a framework based on a 3-tier architecture that illustrates the potential for combining Web 2.0 and Semantic Web technologies. Based on this framework, we present an applic...

The number of open datasets available on the web is increasing rapidly with the rise of the Linked Open Data (LOD) cloud and various governmental efforts for releasing public data in different formats, not only in RDF. The aim in releasing open datasets is for developers to use them in innovative applications, but the datasets need to be found first and metadata available is often minimal, heterogeneous, and distributed making the search for the right dataset often problematic. To address th...

This paper describes the design and implementation of Minimal RDFS semantics based on a backward chaining approach and implemented on a clustered RDF triple store. The system presented, called 4sr, uses 4store as base infrastructure. In order to achieve a highly scalable system we implemented the reasoning at the lowest level of the quad store, the bind operation. The bind operation runs concurrently in all the data slices allowing the reasoning to be processed in parallel among the cluster. ...

The SPARQL query language is currently being extended by W3C with so-called entailment regimes, which define how queries are evaluated under more expressive semantics than SPARQL’s standard simple entailment. We describe a sound and complete algorithm for the OWL Direct Semantics entailment regime. The queries of the regime are very expressive since variables can occur within complex class expressions and can also bind to class or property names. We propose several novel optimizations such as...

A growing number of ontologies have been published on the Semantic Web by various parties, to be shared for describing things. Because of the decentralized nature of the Web, there often exist different but similar ontologies from overlapped domains, or even within the same domain. In this paper, we collect more than four thousand ontologies and perform a large-scale pairwise matching based on an ontology matching tool. We create about three million mappings between the terms (classes and pro...

As the most popular microblogging platform, the vast amount of content on Twitter is constantly growing so that the retrieval of relevant information (streams) is becoming more and more difficult every day. Representing the semantics of individual Twitter activities and modeling the interests of Twitter users would allow for personalization and therewith countervail the information overload. Given the variety and recency of topics people discuss on Twitter, semantic user profiles generated fr...

In Semantic Web, the knowledge sources usually contain inconsistency because they are constantly changing and from different view points. As is well known, as based on the description logic, OWL is lack of the ability of tolerating inconsistent or incomplete data. Recently, the research in handling inconsistency in OWL becomes more and more important. In this paper, we present a paraconsistent OWL called quasi-classical OWL to handle inconsistency with holding important inference rules such a...

We describe the design and use of the Ontology Pre-Processor Language (OPPL) as a means of embedding the use of Knowledge Patterns in OWL ontologies. We illustrate the specification of patterns in OPPL and discuss the advantages of its adoption by Ontology Engineers with respect to ontology generation, transformation, and maintainability. The consequence of the declarative specification of patterns will be their unambiguous description inside an ontology in OWL. Thus, OPPL enables an ontology...