Cost Analysis of Joins in RDF Query Processing Using the TripleT Index By Kanwei Li The Semantic Web movement has led to a growing popularity of RDF and its query languages. Clearly, good query performance is important in allowing information to be quickly retrieved from RDF datasets that are everincreasing in size. We use the TripleT indexing scheme for RDF data as a framework to examine the c...

RDF stores may be used to set up knowledge bases integrating heterogeneous information for web and mobile applications to use the data for new advanced services to citizens and city administrators, thus exploiting inferential capabilities, temporal and spatial reasoning, and text indexing. In this paper, the needs and constraints for RDF stores to be used for smart cities services, together wit...

Although the model-theoretic semantics of the languages used in the Semantic Web are crisps, the need arise to extend them to represent fuzzy data, in the same way fuzzy logic extend first-orderlogic. We will define a fuzzy counterpart of the RDF Model Theory for RDF (section 2) and RDF Schema (section 3). Last, we show how to implement the extended semantics in inference rules (section 4).

Resource Description Framework (RDF) is Meta data model which can be used to store Meta data information of various large complex datasets which can further be used to extract or infer some meaningful out of it. To process these vast amount of data and infer some reasoning out of these is tedious task. Traditional centralized reasoning methods are not sufficient to process large ontologies. Dis...

Metadata processing is recognized as a central challenge for database research in the next decade. Already, novel desktop data management and search applications (cf. Apple’s Spotlight and Microsoft’s WinFS) are enabled by rich metadata. Efficient and effective access to such data becomes a crucial issue for more and more application scenarios. In this article, we focus on metadata represented ...

Akhtar et al. introduced equality-generating constraints and functional constraints as an initial step towards dependency-like integrity constraints for RDF data [1]. Here, we focus on functional constraints. The usefulness of functional constraints is not limited to the RDF data model. Therefore, we study the functional constraints in the more general setting of relations with arbitrary arity....

Large volumes of spatial data and multidimensional are being published on the Semantic Web, which has led to new opportunities for advanced analysis, such as Spatial Online Analytical Processing (SOLAP). The RDF Data Cube (QB) QB4OLAP vocabularies have been widely used annotating publishing statistical data. Although sets might information, coordinates, lack semantics concepts in QB prevents us...

The increasing availability of large RDF datasets offers an exciting opportunity to use such data to build predictive models using machine learning algorithms. However, the massive size and distributed nature of RDF data calls for approaches to learning from RDF data in a setting where the data can be accessed only through a query interface, e.g., the SPARQL endpoint of the RDF store. In applic...