CYC Project

See: CYC System, Cycorp.

References

2017

• (CYC, 2017) ⇒ "Knowledge Base" Retrieved 2017年01月08日 http://www.cyc.com/kb/
  • The Cyc Knowledge Base is so large that it can seem unwieldy and difficult to navigate at first glance.

    The Cyc Knowledge Base (KB) is a formalized representation of a vast quantity of fundamental human knowledge: facts, rules of thumb, and heuristics for reasoning about the objects and events of everyday life. This knowledge is represented in a formal language, CycL. The KB consists of terms and assertions which relate those terms. These assertions include both simple facts (i.e., ground assertions) and rules. The Cyc KB is divided into many (currently thousands of) "contexts" (or "microtheories"), each of which is essentially a collection of assertions that share a common set of assumptions; some microtheories are focused on a particular domain of knowledge, some a particular interval in time, some a particular level of detail, etc. The microtheory mechanism allows Cyc to independently maintain assertions which are prima facie contradictory, and enhances the performance of the Cyc system by focusing the inferencing process. At the present time, the Cyc KB contains over five hundred thousand terms, including about seventeen thousand types of relations, and about seven million assertions relating these terms. New assertions are continually added to the KB through a combination of automated and manual means. Many more concepts can be expressed functionally, thereby enabling the automatic creation of millions of non-atomic terms, such as (LiquidFn Nitrogen) being used to describe liquid nitrogen. Additionally, Cyc adds a vast number of assertions to the KB by itself as a result of the inferencing process.

2007

• (Obitko, 2007) ⇒ Marek Obitko. (2007). "Translations Between Ontologies in Multi-agent Systems - Ontology Operations]." PhD Thesis, Czech Technical University http://www.obitko.com/tutorials/ontologies-semantic-web/body-of-knowledge.html
  • The typical example is the project CYC that defines its knowledge base as an ontology for any other knowledge based system. CYC is the name of a very large, multi-contextual knowledge base and inference engine. CYC is an early attempt to do symbolic AI on a massive scale by capturing common knowledge that is required to do tasks that are trivial for people, but very hard for computers. All of the knowledge in CYC is represented declaratively in the form of logical assertions. CYC contains over 400,000 significant assertions, which include simple statements of facts, rules about what conclusions to draw if certain statements of facts are satisfied, and rules about how to reason with certain types of facts and rules. New conclusions are derived by the inference engine using deductive reasoning. The CYC common sense knowledge can be used as a foundation of a knowledge base for any knowledge intensive system. In this sense, this body of knowledge can be viewed as an ontology of the knowledge base of the system.

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