Three papers written by members of the group were presented at the Extended Semantic Web Conference (ESWC 2011) held in Heraklion, Greece from May 29th to June 2nd. The articles are "Semantics and optimization of the SPARQL 1.1 federation extension", "Lightweight Semantic Annotation of Geospatial RESTful Services" and "A Semantically Enabled Service Architecture for Mashups over Streaming and Stored Data".

OEG members have participated in both articles, Carlos Buil and Oscar Corcho in the first one, Víctor Saquicela, Luis Manuel Vilches and Oscar Corcho in the second one and  Raúl García-Castro, Jean-Paul Calbimonte, Oscar Corcho and Asunción Gómez-Pérez in the third one.

"Semantics and optimization of the SPARQL 1.1 federation extension". The W3C group is developing version 1.1 of the SPARQL query language. In this article we describe a possible formalization of the syntax and semantics of the extension of SPARQL 1.1 to federate queries. Furthermore, we propose and implement a set of optimization techniques for this extension, and develop an evaluation system that shows how the application of such optimizations substantially improve system performance.

"Lightweight Semantic Annotation of Geospatial RESTful Services". RESTful services are increasingly gaining traction over WS-* ones. As with WS-* services, their semantic annotation can provide benefits in tasks related to their discovery, composition and mediation. In this paper we present an approach to automate the semantic annotation of RESTful services using a cross-domain ontology like DBpedia, domain ontologies like GeoNames, and additional external resources (suggestion and synonym services). We also present a preliminary evaluation in the geospatial domain that proves the feasibility of our approach in a domain where RESTful services are increasingly appearing and highlights that it is possible to carry out this semantic annotation with satisfactory results.

"A Semantically Enabled Service Architecture for Mashups over Streaming and Stored Data". Sensing devices are increasingly being deployed to monitor the physical world around us. One class of application for which sensor data is pertinent is environmental decision support systems, e.g. flood emergency response. However, in order to interpret the readings from the sensors, the data needs to be put in context through correlation with other sensor readings, sensor data histories, and stored data, as well as juxtaposing with maps and forecast models. In this paper we use a flood emergency response planning application to identify requirements for a semantic sensor web. We propose a generic service architecture to satisfy the requirements that uses semantic annotations to support well-informed interactions between the services. We present the SemSorGrid4Env realisation of the architecture and illustrate its capabilities in the context of the example application.