Automaton

A common representation of an automaton in computer science. This automaton "accepts" all the sequences of the letters a and b which start with an a and end with a b.

An Automaton (one automaton, several automata) is a concept from mathematics. Sometimes the concept is called state machine. It is like an abstract machine.

Such a machine can be given input, which is either rejected, or accepted. It's like a vending machine. When something is bought, coins (or money) needs to be inserted into the machine. If these are the right coins, they are accepted, and the requested item is dropped so it can be removed. If the coins are wrong, they are rejected.

Internally, the automaton has different states it can be in. Feeding it input may (or may not) change its state. That way, the automaton goes through all the input, consuming one item (which mathematicians call a symbol) at a time. When no symbol is left, the automaton is in a certain state. This may be an final state. In this case the input is accepted. Otherwise, the input is rejected.

If the machine has a countable, finite number of states, it is called finite state machine. A diagram that shows all the states, and transitions of such a machine is called finite state diagram.

Problems

Like in real life, there are machines that are too complex to understand. The mathematician and computer scientists therefore ask themselves if a certain automaton is minimal. If it is not minimal, there must be another automaton with fewer states that can do the same thing. An example of an automaton is the Turing machine.

Automaton Media

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  A postulated interior of the Duck of Vaucanson (1738–1739)

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  Mechanical Pinochio puppet.

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  The book About automata by Hero of Alexandria (1589 edition)

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  The Antikythera mechanism from 150 to 100 BC was designed to calculate the positions of astronomical objects.

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  Automaton in the Swiss Museum CIMA

• An automaton writing a letter in Swiss Museum CIMA

• A cuckoo clock with a built in automaton of a cuckoo that flaps its wings and opens its beak in time to the sounds of the cuckoo call to mark the number of hours on the analogue dial

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  Bell-ringing Death on Prague astronomical clock

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  A Japanese automata theater in Osaka, drawn in 18th century. The Takeda family opened their automata theater in 1662.

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  Elephant automaton at Waddesdon Manor

• Maillardet's automaton is drawing a picture.