Sesame is an Open Source RDF Schema-based repository and querying facility. It is a scalable, modular architecture for persistent storage and querying of RDF and RDF Schema. It supports two query languages (SPARQL and SeRQL), and can use main memory or PostgreSQL, MySQL and Oracle 9i databases for storage.
Rasqal is a C library for querying RDF graphs, supporting the SPARQL, RDQL, and LAQRS languages. It provides APIs for creating a query and parsing query syntax. It features pluggable triple-stores and matching interfaces, query engines for executing the queries, an API for manipulating results as bindings, and multiple ways to format the results to XML, CSV, TSV, and JSON. It uses the Raptor RDF parser to return triples from RDF content, and can alternatively work with the Redland RDF library's persistent triple stores. It is portable across many POSIX systems.
Soprano (formerly known as QRDF) is a library that provides a highly usable object-oriented C++/Qt4 framework for RDF data. It uses different RDF storage solutions as backends through a simple plugin system. Soprano is targetted at desktop applications that need a RDF data storage solution. It has been optimized for easy usage and simplicity.
Nx2 is a somewhat complex Web application that acts as a frontend to music databases. Based on XUL, it runs in Gecko based browsers such as Firefox. Built on this idea is a client/server model where several Nx2 frontends can connect to each other, creating a way to link together databases on different networks.
ASTRA is a set of software tools for mediated interpersonal awareness, addressing the need to stay in touch with family and friends or the need to be reassured regarding their well-being. The software provides a service oriented architecture, user tools, and applications that support communities to appropriate Pervasive Awareness applications.