Col-Graph: Towards Writable and Scalable Linked Open Data

International audienceLinked Open Data faces severe issues of scalability, availability and data quality. these issues are observed by data consumers performing federated queries; SPARQL endpoints do not respond and results can be wrong or out-of-date. If a data consumer finds an error, how can she fix it? This raises the issue of the writability of Linked Data. In this paper, we devise aan extension of the federation of Linked Data to data consumers. A data consumer can make partial copies of different datasets and make them available through a SPARQL endpoint. A data consumer can update her local copy and share updates with data providers and consumers. Update sharing improves general data quality, and replicated data creates opportunities for federated query engines to improve availability. However, when updates occur in an uncontrolled way, consistency issues arise. In this paper, we define fragments as SPARQL CONSTRUCT queries and propose a correction criterion to maintain these fragments incrementally without reevaluating the query. We define a coordination free protocol based on the counting of triples derivations and provenance. We analyze the theoretical complexity of the protocol in time, space and traffic. Experimental results suggest the scalability of our approach

Semantic Versioning of In-Process Scientific Document

Part 1: Information & Communication Technology-EurAsia Conference 2014, ICT-EurAsia 2014International audienceThe development of scientific documents is an iterative process. Scientific documents go through a continuous informal review phase during writing process and as a result keep changing. The informal review changes are casually recorded. The key issue for maintaining the changes in scientific document is to maintain the review history of individual components within source file at component level. Scientific document is meaningfully organized and it can be easily transformed into an ontology. For this purpose, we use Document Ontology to map each component of the scientific document and manage changes in this ontology by enhancing an already existing technique of semantic repository versioning. In this paper, we explore document change process using semantic versioning and provide the review comments history along each change. In addition, we define a usage scenario to present the viability and benefit of our approach. To achieve this, we developed a prototype system which represents the meaningful track of change in individual components of a scientific document, provides the review comments history along each change and at the end of document writing the author can see the progress report

Tracking Changes during Ontology Evolution

As ontology development becomes a collaborative process, developers face the problem of maintaining versions of ontologies akin to maintaining versions of software code or versions of documents in large projects. Traditional versioning systems enable users to compare versions, examine changes, and accept or reject changes. However, while versioning systems usually treat software code and text documents as text files, a versioning system for ontologies must compare and present structural changes rather than changes in text representation of ontologies. In this paper, we present the PROMPTDIFF ontology-versioning environment, which address these challenges. PROMPTDIFF includes an efficient version-comparison algorithm that produces a structural diff between ontologies. The results are presented to the users through an intuitive user interface for analyzing the changes that enables users to view concepts and groups of concepts that were added, deleted, and moved, distinguished by their appearance and with direct access to additional information characterizing the change. The users can then act on the changes, accepting or rejecting them. We present results of a pilot user study that demonstrate the effectiveness of the tool for change management. We discuss design principles for an end-to-end ontology-versioning environment and position ontology versioning as a component in a general ontology-management framework

Version Control and Change Validation for RDF Datasets

The dynamic and distributed nature of the Semantic Web demands for methodologies and systems fostering collective participation to the evolution of datasets. In collaborative and iterative processes for dataset development, it is important to keep track of individual changes for provenance. Different scenarios may require mechanisms to foster consensus, resolve conflicts between competing changes, reversing or ignoring changes etc. In this paper, we perform a landscape analysis of version control for RDF datasets, emphasizing the importance of change reversion to support validation. Firstly, we discuss different representations of changes in RDF datasets and introduce higher-level perspectives on change. Secondly, we analyze diverse approaches to version control. We conclude by focusing on validation, characterizing it as a separate need from the mere preservation of different versions of a dataset