Semantic Reasoners

A semantic reasoner, reasoning engine, rules engine, or simply a reasoner, is a piece of software able to infer logical consequences from a set of asserted facts or axioms. The notion of a semantic reasoner generalizes that of aninference engine, by providing a richer set of mechanisms to work with. The inference rules are commonly specified by means of an ontology language, and often a description language. Many reasoners use first-order predicate logic to perform reasoning; inference commonly proceeds by forward chaining and backward chaining. There are also examples of probabilistic reasoners, including Pei Wang's non-axiomatic reasoning system, Novamente's probabilistic logic network, which tip their hat to reasoning Bayesian networks, and Pronto - probabilistic description logic reasoner.

Some open - source reasoners  than can be used with Protege and OWL API are:

Pellet

Fact ++

and HermiT

Reasoner - Pellet

Hello!

It's been a long time since my last post (once again.. :( - sorry).

Today I will introduce you Pellet, the reasoner I've been using the last 4-5 months. Pellet is compatible with Protégé (via a plug in ), Jena and OWL API.

As far as I am concerned, I am using OWL and I find Pellet very quick and handy. I've also tried HermiT but I wasn't very satisfied.

From the official site of Pellet I copy - paste this:

For applications that need to represent and reason about information using OWL, Pellet is the leading choice for systems where sound-and-complete OWL DL reasoning is essential. Pellet includes support for OWL 2 profiles including OWL 2 EL. It incorporates optimizations for nominals, conjunctive query answering, and incremental reasoning. There’s more detailed information about the architecture of the system and its features in Pellet Help.

An OWL DL reasoner like Pellet is a core component of ontology-based data management applications; if you need expertise in the use of Pellet for advanced integration or analysis applications, Clark & Parsia LLC can help in a variety of roles: consulting, application development, and OEM licensing.

Cheers,
Angeliki

Semantic Web keywords

• Semantic Web: Semantic Web is a group of methods and technologies to allow machines to understand the meaning - or "semantics" - of information on the "World Wide Web". (wikipedia)
• Ontology: In computer and information science, an ontology is a formal representation of knowledge as a set of concepts within a domain, and the relationships between those concepts. It is used to reason (see reasoning definition)about the entities within that domain, and may be used to describe the domain.(wikipedia)
• Reasoning : Reasoning is the cognitive process of looking for reasons, beliefs, conclusions, actions or feelings. (wikipedia)
• OWL: The Web Ontology Language (OWL) is a family of knowledge representation languages for authoring ontologies. The languages are characterised by formal semantics and RDF/XML-based serializations for the Semantic Web. OWL is endorsed by the World Wide Web Consortium (W3C) and has attracted academic, medical and commercial interest. In October 2007, a new W3C working group was started to extend OWL with several new features as proposed in the OWL 1.1 member submission. This new version, called OWL 2, soon found its way into semantic editors such as Protégé and semantic reasoners such as Pellet,RacerPro, FaCT++ and HermiT. (wikipedia)

Cheers,
Angeliki