Semantic Web
RDF
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- RDF Schema describes how to use RDF to describe RDF vocabularies. It provides mechanisms for describing groups of related resources and the relationships between these resources.
- Java Annotations & the Semantic Web by Henry Story describes the possibilities of RDF-to-Java mapping.
To read:
RDF Storage Engines / Libraries
- Sesame Triple Store
- Mulgara is a scalable RDF database (triplestore) and fork of the original Kowari project written entirely in Java. Can be queried via iTQL and SPARQL query language.
- Redland RDF Libraries is a set of free software C libraries that provide support for RDF.
- OpenLink Virtuoso is Universal Server to implement Web, File, and Database server functionality alongside Native XML Storage, and Universal Data Access Middleware, as a single server solution. It includes support for key Internet, Web, and Data Access standards such as: XML, XPATH, XSLT, SOAP, WSDL, UDDI, WebDAV, SMTP, SQL, ODBC, JDBC, and OLE-DB. It has native connectors to the following fraweworks: Jena, Sesame and Redland.
- Aperture is an open source Java framework for extracting full-text content and metadata from various information systems (e.g. file systems, web sites, mail boxes) and the file formats (e.g. documents, images) occurring in these systems. Data exchange based on Semantic Web standards (e.g. RDF).
Benchmarks:
- RDF Store Benchmarking provides some testing material and Large Triple Stores lists those of them with good scalability.
- (outdated) Survey of RDF/Triple Data Stores
To read:
RDF Mapping
- RDF/XML → XSL/Fresnel lens/JSON.
- Sesame Elmo POJO mapping tool module.
- Custom data access layer.
- Storage and Querying of E-Commerce Data – makes a comparison of horizontal, vertical, and binary (table per attribute = predicate) presentations of XML data (online)
- You can find the comparison of different approaches to map RDF to SQL in Mapping Semantic Web Data with RDBMSes.
SPARQL
To read:
OWL
- Pellet is an open source reasoner for OWL 2 DL in Java which provides standard and cutting-edge reasoning services for OWL ontologies.
Online tools:
To read:
SKOS
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- SKOS Primer provides introductory examples and guidance in the use of the SKOS vocabulary.
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- Concept Web – a dynamic, interactive fabric of concepts and their relationships. The Concept Web is constructed from, inter alia, research literature, Internet databases and other web sites together with off-line resources. The aim of creating the Concept Web is to remove both redundancy and ambiguity from available knowledge in order to help deal with information overload, to semantically «connect» concepts, and so to maximize the potential for knowledge discovery.
To read:
Vocabulary
reincation – a form of RDF in which any RDF statement itself can be the subject or object of a triple. This means graphs can be nested as well as chained. On the Web this allows us, for example, to express doubt or support for statements created by other people
query statements inferencer – the ability of query processor to intercept and preprocess new statements as needed to enable data semantic support (e.g. RDF), which in Sesame is implemented for SAIL6)
ontology reasoner – basically checks that ontology makes sense (consistency checking, concept satisfiability). A reasoner creates an entailment of the RDF graph by following rules through the unification/resolution process to their transitive closure.
