- published: 15 Apr 2010
- views: 10729
Wikipedia (i/ˌwɪkɨˈpiːdiə/ or i/ˌwɪkiˈpiːdiə/ WIK-i-PEE-dee-ə) is a free, collaboratively edited and multilingual Internet encyclopedia supported by the non-profit Wikimedia Foundation. Its 22 million articles (over 0 million in English alone) have been written collaboratively by volunteers around the world. Almost all of its articles can be edited by anyone with access to the site, and it has about 100,000 regularly active contributors. As of June 2012, there are editions of Wikipedia in 285 languages. It has become the largest and most popular general reference work on the Internet, ranking sixth globally among all websites on Alexa and having an estimated 365 million readers worldwide. It is estimated that Wikipedia receives 2.7 billion monthly pageviews from the United States alone.
Wikipedia was launched in January 2001 by Jimmy Wales and Larry Sanger. Sanger coined the name Wikipedia, which is a portmanteau of wiki (a type of collaborative website, from the Hawaiian word wiki, meaning "quick") and encyclopedia. Wikipedia's departure from the expert-driven style of encyclopedia building and the presence of a large body of unacademic content have received extensive attention in print media. In its 2006 Person of the Year article, Time magazine recognized the rapid growth of online collaboration and interaction by millions of people around the world. It cited Wikipedia as an example, in addition to YouTube, MySpace, and Facebook. Wikipedia has also been praised as a news source because of how quickly articles about recent events appear. Students have been assigned to write Wikipedia articles as an exercise in clearly and succinctly explaining difficult concepts to an uninitiated audience.
In the context of hardware and software systems, formal verification is the act of proving or disproving the correctness of intended algorithms underlying a system with respect to a certain formal specification or property, using formal methods of mathematics[citation needed].
Complete formal verification is the only known way to guarantee that a system is free of programming errors.
Formal verification can be helpful in proving the correctness of systems such as: cryptographic protocols, combinational circuits, digital circuits with internal memory, and software expressed as source code.
The verification of these systems is done by providing a formal proof on an abstract mathematical model of the system, the correspondence between the mathematical model and the nature of the system being otherwise known by construction. Examples of mathematical objects often used to model systems are: finite state machines, labelled transition systems, Petri nets, timed automata, hybrid automata, process algebra, formal semantics of programming languages such as operational semantics, denotational semantics, axiomatic semantics and Hoare logic.[citation needed]