Jena is a Java framework for building Semantic Web applications. It provides a programmatic environment for RDF, RDFS and OWL, SPARQL and includes a rule-based inference engine.
The OWL API is a Java API and reference implmentation for creating, manipulating and serialising OWL Ontologies. The latest version of the API is focused towards OWL 2
The SEALS Community is a worldwide group of individuals and organizations interested in the evaluation of semantic technologies.
This community will give semantic tool researchers, vendors and users the opportunity to participate in tool evaluations, as well as find and exchange evaluation opinions, materials and results that support their technology evaluation and selection activities.
Protégé is a free, open source ontology editor and knowledge-base framework. The Protégé platform supports two main ways of modeling ontologies via the Protégé-Frames and Protégé-OWL editors. Protégé ontologies can be exported into a variety of formats including RDF(S), OWL, and XML Schema. (more) Protégé is based on Java, is extensible, and provides a plug-and-play environment that makes it a flexible base for rapid prototyping and application development. (more)
Many biomedical terminologies, classifications, and ontological resources such as the NCI Thesaurus (NCIT), International Classification of Diseases (ICD), Systematized Nomenclature of Medicine (SNOMED), Current Procedural Terminology (CPT), and Gene Ontology (GO) have been developed and used to build a variety of IT applications in biology, biomedicine, and health care settings
The Lexical Grid LexGrid provides support for a distributed network of lexical resources such as terminologies and ontologies via standards-based tools, storage formats, and access/update mechanisms.
One of my collegaues called the other day and asked if we still relied on the distinction between intensional and extensional sets (really intensionally and extensionally defined sets). Yes, even more so now.
This document describes an ontology for publishing descriptions of historical events as Linked Data, and for mapping between other event-related vocabularies and ontologies.
J. Attard, S. Scerri, I. Rivera, and S. Handschuh. Proceedings of the 9th International Conference on Semantic Systems, page 113--120. New York, NY, USA, ACM, (2013)