S-RDF: A New RDF Serialization Format for Better Storage Without Losing Human Readability

International audienceNowadays, RDF data becomes more and more popular on the Web due to the advances of the Semantic Web and the Linked Open Data initiatives. Several works are focused on transforming relational databases to RDF by storing related data in N-Triple serialization format. However, these approaches do not take into account the existing normalization of their databases since N-Triple format allows data redundancy and does not control any normalization by itself. Moreover, the mostly used and recommended serialization formats, such as RDF/XML, Turtle, and HDT, have either high human-readability but waste storage capacity, or focus further on storage capacities while providing low human-readability. To overcome these limitations, we propose here a new serialization format, called S-RDF. By considering the structure (graph) and values of the RDF data separately, S-RDF reduces the duplicity of values by using unique identifiers. Results show an important improvement over the existing serialization formats in terms of storage (up to 71,66% w.r.t. N-Triples) and human readability

Інструментальні засоби підключення реляційної бази даних до онтології предметної області

Обсяг дипломної роботи складає 57 сторінок, 13 рисунків, 3 додатки та 5 посилань. Мета роботи – створити програмний додаток, який дозволяє підключити реляційну базу даних до онтології предметної області для проведення обміну даними. У ході роботи було розглянуто редактор існуючі рішення, а саме редактор онтологій Protégé. Проаналізовано підходи до реалізації взаємодії онтології та реляційних баз даних. Розроблено систему спільної роботи онтології та реляційної бази даних.The volume of the thesis is 57 pages, 13 figures, 3 appendices and 5 references. The purpose of the work is to create a software application that allows you to connect a relational database to the ontology of the subject area. In the course of the work, the editor of the existing solutions, namely the editor of ontologies Protégé, was considered. Approaches to the implementation of the interaction of ontology and relational databases are analyzed. A system of joint work of ontology and relational database has been developed.Объем дипломной работы составляет 57 страниц, 13 рисунков, 3 приложения и 5 ссылок. Целью работы является создание программного приложения, позволяющего подключить реляционную базу данных к онтологии предметной области. В ходе работы был рассмотрен редактор существующих решений, а именно редактор онтологий Protégé. Анализируются подходы к реализации взаимодействия онтологии и реляционных баз данных. Разработана система совместной работы онтологий и реляционных баз данных

RDB to RDF 변환을 위한 의미 정보 보존 맵리듀스 처리

학위논문 (석사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2015. 8. 김형주.Today, most of the data on the web is stored in relational databases, which is called deep web. Semantic web is a movement to the next generation of the web, where all data are augmented with well-defined semantics and linked together in machine-readable format. RDB2RDF approaches have been proposed and standardized by W3C, which publishes relational data to semantic web by converting relational data into RDF formatted data. We propose a system that automatically transforms relational data into RDF data and creates OWL ontology based on the schema of database. Some approaches have been proposed, but most of them did not fully make use of schema information to extract rich semantics, nor did they experimented on large databases for performance. We utilize Hadoop framework in transformation process, which enables distributed system for scalability. We present mapping rules that implements augmented direct mapping to create local ontology with rich semantics. The results show that our system successfully transforms relational data into RDF data with OWL ontology, with satisfactory performance on large-sized databases.Abstract i Introduction 3 Related Work 7 2.1 Semantic ETL Systems 7 2.2 Hadoop MapReduce 8 2.3 Mapping Approaches 9 Mapping Rules 14 3.1 General Rule 1 19 3.2 General Rule 2 20 3.3 General Rule 3 20 3.4 General Rule 4 21 3.5 General Rule 5 21 3.6 Constraint Rule 1 22 3.7 Constraint Rule 2 22 3.8 Constraint Rule 3 23 3.9 Constraint Rule 4 24 3.10 Constraint Rule 5 24 3.11 Constraint Rule 6 25 3.12 Discussion 26 Our Approach 28 4.1 Preprocessing 28 4.1.1 Schema Caching Method 30 4.1.2 Relational Data 32 4.2 Hadoop Algorithm 33 Experiment 36 5.1 Ontology Extraction 37 5.2 Performance 38 5.3 Scalability 41 Conclusion 42 Reference 44 Appendix 46Maste

A Complex Web: Upgrading to Linked Data in Digital Repositories

As libraries, archives, and museums (“LAMs”) adopt linked data for purposes of enhancing their bibliographic and authority metadata, the technologies around digital repositories also are similarly changing course to model digital objects using linked data standards such as RDF. This study explores the digital repository community's engagement and perceptions of linked data modeling. The study is split into two phases consisting of a web survey and semi-structured interviews. Qualitative analysis of the data summarizes key characteristics of the community of practice, and open problems in transitioning to linked data in the redesign of the Fedora storage and preservation architecture commonly used in digital repositories. Other areas of discussion include the perceived concerns in cross-walking MODS to RDF, as well as the community’s recommended implementation of the Portland Common Data Model (PCDM).Master of Science in Information Scienc