Layer-Oriented MCAO is a promising technique that can scale up easily compared to similar competing techniques. The Multiple-Field-of-View Layer-Oriented makes a further step employing more guide stars to sample the turbulence with the net effect of increasing the sky coverage, thereby enabling MCAO systems based only natural guide stars. However even a simple estimation of Layer-Oriented M-FoV...

In this paper we propose a method for efficient management of large spatial ontologies. Current spatial ontologies are usually represented using an ontology language, such as OWL and stored as OWL files. However, we have observed some shortcomings using this approach especially in the efficiency of spatial query processing. This fact motivated the development of a hybrid approach that uses an R...

Although OWL, an emerged standard of expressing ontologies in the Semantic Web, is a very expressive ontology language, the OWL datatyping formalism is far not expressive enough to generally represent user-defined datatypes (such as XML Schema derived datatypes), not to mention user-defined datatype predicates (such as > for non-negative integers) in Semantic Web ontologies and applications. In...

OWL-S is an application of OWL, theWeb Ontology Language, that describes the semantics of Web Services so that their discovery, selection, invocation and composition can be automated. The research literature reports the use of UML diagrams for the automatic generation of Semantic Web Service descriptions in OWL-S. This paper demonstrates a higher level of automation by generating complete compl...

The wide scale usage of OWL for the formalization of real-world ontologies is currently influenced by important limitations which concern both its expressivity and the efficiency of OWL specific reasoning tools. While the expressivity limitations may be overcame by extending the OWL language (e.g. with rules), the reasoning with such heterogeneous knowledge bases is still an open issue. In this...

One of the main aims of the so-called Web of Data is to be able to handle heterogeneous resources where data can be expressed in either XML or RDF. The design of programming languages able to handle both XML and RDF data is a key target in this context. In this paper we present a framework called XQOWL that makes possible to handle XML and RDF/OWL data with XQuery. XQOWL can be considered as an...

There are many query languages (QLs) that can be used to query RDF and OWL ontologies but neither type is satisfactory for querying OWL-DL ontologies. RDF-based QLs (RDQL, SeRQL, SPARQL) are harder to give a semantics w.r.t. OWL-DL and are more powerful than what OWL-DL reasoners can provide. DL-based QLs (DIG ask queries, nRQL) have clear semantics but are not powerful enough in the general ca...

The Orthant-Wise Limited memory QuasiNewton (OWL-QN) method has been demonstrated to be very effective in solving the l1regularized sparse learning problem. OWL-QN extends the L-BFGS from solving unconstrained smooth optimization problems to l1-regularized (non-smooth) sparse learning problems. At each iteration, OWL-QN does not involve any l1regularized quadratic optimization subproblem and on...

In addition to taxonomic knowledge about concepts and properties typically expressible in languages such as RDFS and OWL, implicit information in an RDF graph may be likewise determined by arithmetic equations. The main use case here is exploiting knowledge about functional dependencies among numerical attributes expressible by means of such equations. While some of this knowledge can be encode...

Knowledge base exchange is an important problem in the area of data exchange and knowledge representation, where one is interested in exchanging information between a source and a target knowledge base connected through a mapping. In this paper, we study this fundamental problem for knowledge bases and mappings expressed in OWL 2 QL, the profile of OWL 2 based on the description logic DL-LiteR....