Parallel RDF generation from heterogeneous big data

To unlock the value of increasingly available data in high volumes, we need flexible ways to integrate data across different sources. While semantic integration can be provided through RDF generation, current generators insufficiently scale in terms of volume. Generators are limited by memory constraints. Therefore, we developed the RMLStreamer, a generator that parallelizes the ingestion and mapping tasks of RDF generation across multiple instances. In this paper, we analyze what aspects are parallelizable and we introduce an approach for parallel RDF generation. We describe how we implemented our proposed approach, in the frame of the RMLStreamer, and how the resulting scaling behavior compares to other RDF generators. The RMLStreamer ingests data at 50% faster rate than existing generators through parallel ingestion

A vocabulary-independent generation framework for DBpedia and beyond

The dbpedia Extraction Framework, the generation framework behind one of the Linked Open Data cloud’s central hubs, has limitations which lead to quality issues with the dbpedia dataset. Therefore, we provide a new take on its Extraction Framework that allows for a sustainable and general-purpose Linked Data generation framework by adapting a semantic-driven approach. The proposed approach decouples, in a declarative manner, the extraction, transformation, and mapping rules execution. This way, among others, interchanging different schema annotations is supported, instead of being coupled to a certain ontology as it is now, because the dbpedia Extraction Framework allows only generating a certain dataset with a single semantic representation. In this paper, we shed more light to the added value that this aspect brings. We provide an extracted dbpedia dataset using a different vocabulary, and give users the opportunity to generate a new dbpedia dataset using a custom combination of vocabularies

Towards an interface for user-friendly linked data generation administration

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Potential of existing prefabricated components for sustainable renovation of buildings

Since 2015, energy performance requirements in Flanders (Belgium) also apply to existing buildings undergoing major renovation works. In this context, prefabricated façade components have a large potential for renovating the existing building stock in a fast and repeatable way. Benefits of this technique are functionality during renovation works, possibility of integrating HVAC systems and the limited number of activities on site. On the other hand, the preparatory work is more extensive and there is a lack of experience with the application of prefabricated components in renovation projects. Consequently, prefabricated systems are seldom applied. A recently started research project aims to stimulate the development and use of these systems by providing tools that permit to make a founded assessment of the effectiveness of prefabricated systems: a decision tool, a cost calculator and technical solutions including air- and watertightness, acoustics, fire safety and guidelines for a minimal risk on hygrothermal damage will be developed. This paper can be seen as a first step: an overview of the multiple systems that are described in commercial and academic literature is presented. The paper not only elaborates on timber frame systems, which are most frequently used, but also modules constructed of cold formed steel, composite and concrete systems are discussed. Next to that, a first test set-up in the research project, focussing on the air- and watertightness of wide junctions, is discussed. The main purpose of the test is to compare several existing systems for the creation of an airtight layer at the exterior surface. In the future, this test will be executed and other research scenarios will be elaborated