http://dl.gi.de/handle/20.500.12116/22390 Tue, 21 Jul 2026 13:26:07 GMT 2026-07-21T13:26:07Z http://dl.gi.de:80/bitstream/id/9b5b019e-7cd5-4bd9-aa56-8c66e085025f/ http://dl.gi.de/handle/20.500.12116/22390 http://dl.gi.de/handle/20.500.12116/22410 Mapping Cognitive Models to Social Semantic Spaces – Collaborative Development of Project Ontologies Riechert, Thomas; Lohmann, Steffen Auer, Sören; Bizer, Christian; Müller, Claudia; Zhdanova, Anna V. In this paper, we present an approach that applies concepts from the areas of Social Software and Semantic Web to application development. We start with a short introduction into Semantic Based Requirements Engineering. Then, we present an ontology for capturing requirements and related information. Based on this ontology, we describe how stakeholders are enabled to directly participate in requirements elicitation and to collaboratively create a project ontology. Finally, we report about the application of the presented approach in a use case from the e-government domain. Mon, 01 Jan 2007 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/22410 2007-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/22409 Collaborative Metadata for Geographic Information Maué, Patrick Auer, Sören; Bizer, Christian; Müller, Claudia; Zhdanova, Anna V. Retrieval of web-based geographic information (GI) for spatial decision- making processes can benefit from emerging semantic technologies. Ontology-supported metadata, collaboratively created by a social network of spatially-aware users, ensures efficient and precise discovery of maps published with the help of catalogs. The creation and maintenance of the metadata is driven by two forces: on the one hand experienced catalogers who ensure consistency and quality, on the other hand catalog users who continuously adapt and extend the metadata. We discuss the requirements for a catalog for GI which is able to capture the semantics emerging within a community and apply the results to the registered metadata. Mon, 01 Jan 2007 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/22409 2007-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/22408 Implementing SPARQL Support for Relational Databases and Possible Enhancements Weiske, Christian; Auer, Sören Auer, Sören; Bizer, Christian; Müller, Claudia; Zhdanova, Anna V. In order to make the Semantic Web real we need the infrastructure to store, query and update information adhering to the RDF paradigm. Such infrastructure can be developed from scratch or benefit from developments and experiences made in other science & technology realms such as within the database domain. For querying RDF data the World Wide Web Consortium released a Working Draft for the SPARQL query language. A large portion of the Web is meanwhile driven by server-side Web applications. PHP is the scripting language most widely used for Web applications. In this paper we present our PHP implementation of the SPARQL standard directly interacting with an underlying database system. The approach is based on the rationale of pushing as much work into the RDBMS as possible in order to profit most from the query optimization techniques developed for relational database systems. The article includes an evaluation of the performance and standard compliance, surveys limitations we discovered when using SPARQL for the implementation of real-life Semantic Web applications and suggests extensions to the SPARQL standard in order to solve these obstacles. Mon, 01 Jan 2007 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/22408 2007-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/22407 RDF Support in the Virtuoso DBMS Erling, Orri; Mikhailov, Ivan Auer, Sören; Bizer, Christian; Müller, Claudia; Zhdanova, Anna V. This paper discusses RDF related work in the context of OpenLink Virtuoso, a general purpose relational / federated database and applications platform. We discuss adapting a relational engine for native RDF support with dedicated data types, bitmap indexing and SQL optimizer techniques. We further discuss mapping existing relational data into RDF for SPARQL access without converting the data into physical triples. We present conclusions and metrics as well as a number of use cases, from DBpedia to bio informatics and collaborative web applications. Mon, 01 Jan 2007 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/22407 2007-01-01T00:00:00Z