The availability of SPARQL endpoints on the Web provides interesting opportunities for rapid Web application development. However, sophisticated applications need components that can adopt to the data, yet, the efficient generic exploration and visualization of data contained in those endpoints is still challenging. In this paper, we present the “JAvascript Suite for Sparql Access” (Jassa) fram...

SQL developers are used to work with elaborate tools which help them in writing queries. In contrast, the creation of tools to assist users in the development of SPARQL queries is still in its infancy. In this system demo, we present the SPARQL Analysis and Manipulation (SPAM) tool, which provides help for the development of SPARQL queries. The main features of the SPAM tool comprise an editor ...

Smart environments require collaboration of multi-platform sensors operated by multiple parties. Proprietary event processing solutions lack interoperation flexibility, leading to overlapping functions that can waste hardware and communication resources. Our goal is to show the applicability of standard RDF and SPARQL – including SPARQL 1.1 Update – for complex event processing tasks. If found ...

SPARQL queries can be represented in RDF in order to work with them as first-class citizen in Semantic Web applications. The representation used so far, SPIN SPARQL, closely follows the abstract syntax tree, but fails to directly capture the semantics and is hard to work with for query rewriting. Here a novel vocabulary based on SPARQL Algebra is presented. The adequacy of the language is empir...

Sparklis is a Semantic Web tool that helps users explore SPARQL endpoints by guiding them in the interactive building of questions and answers, from simple ones to complex ones. It combines the fine-grained guidance of faceted search, most of the expressivity of SPARQL, and the readability of (controlled) natural languages. No endpoint-specific configuration is necessary, and no knowledge of SP...

The amount of Linked Data has been growing increasingly. However, the efficient use of that knowledge is hindered by the lack of information about the data structure. This is reflected by the difficulty of writing SPARQL queries. In order to improve the user experience, we propose an auto-completion library for SPARQL that suggests possible RDF terms. In this work, we investigate the feasibilit...

The SPARQL 1.1 Query Language [1] permits patterns inside FILTER expressions using the EXISTS construct, specified by using substitution. Substitution destroys some of the aspects of SPARQL that make it suitable as a data access language. As well, substitution causes problems in the SPARQL algebra and produces counterintuitive results. Fixing the problems with EXISTS is best done with a complet...