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A knowledge base or knowledgebase (also KB or kb) ) is a special kind of database for knowledge management. A knowledge base is an information repository that provides a means for information to be collected, organized, shared, searched and utilized. It can be either machine-readable or intended for human use.
Machine-readable knowledge bases 
Machine-readable knowledge bases store knowledge in a computer-readable form, usually for the purpose of having automated deductive reasoning applied to them. They contain a set of data, often in the form of rules that describe the knowledge in a logically consistent manner. An ontology can define the structure of stored data - what types of entities are recorded and what their relationships are. Logical operators, such as And (conjunction), Or (disjunction), material implication and negation may be used to build it up from simpler pieces of information. Consequently, classical deduction can be used to reason about the knowledge in the knowledge base. Some machine-readable knowledge bases are used with artificial intelligence, for example as part of an expert system that focuses on a domain like prescription drugs or customs law. Such knowledge bases are also used by the semantic web.
See also List of artificial intelligence projects.
Human-readable knowledge bases 
Human-readable knowledge bases are designed to enable people to retrieve and use the knowledge they contain. They are commonly used to complement a help desk or for sharing information among employees within an organization. They might store troubleshooting information, articles, white papers, user manuals, knowledge tags, or answers to frequently asked questions. Typically, a search engine is used to locate information in the system, or users may browse through a classification scheme.
A text-based system that can include groups of documents with hyperlinks among them is known as a Hypertext System. Hypertext systems support the decision process by relieving the user of the significant effort it takes to relate and remember things."  Wiki software can be used to provide a hypertext-system KB. Knowledge bases can exist on both computers and mobile phones in a hypertext format.
A human-readable knowledge base can be coupled with a machine-readable one, via uni- or bidirectional replication or some real-time interface. Computer programs can then use AI techniques on the computer-readable portion of data to provide better search results, check the integrity of facts found in different documents, and provide better authoring tools. An example is the machine-readable DBpedia extraction from human-readable Wikipedia.
Categories of knowledge base information 
Human-readable knowledge bases can contain information of the following types:
- Process and Procedures
- Illustrations, such as flowcharts or other types of graphics.
Knowledge base analysis and design 
Knowledge base analysis and design (KBAD) is a process that enables people to conduct analysis and design of information in a way that results in a knowledge base. This approach was first implemented by Steven H. Dam.
See also 
- Knowledge management
- Information repository
- Content management
- Commonsense knowledge base
- Enterprise bookmarking
- Text mining
- Argumentation in Artificial Intelligence by Iyad Rahwan, Guillermo R. Simari
- "OWL DL Semantics". Retrieved 10 December 2010.
- "Knowledge Base Template". Matthewb.id.au. Retrieved 2012-05-18.
- Marakas, George. Decision Support Systems in the 21st Century. Prentice Hall, 1999, p.29
- Shared Knowledge Base for Mobile Phone and Computer
- Steven H. Dam, Ph.D. KBAD – A Cost-Effective Way to Conduct Design and Analysis. Systems and Proposal Engineering Company (SPEC), 2009
- "Knowledge Based Systems"
- Content Repository API
- Computability Logic Homepage
- Protégé, an open source ontology editor and knowledge-base framework
- OMCSNet-WNLG, partial wordsense disambiguated version of the OMCSNet knowledge base
- Writing knowledge-based articles