Input is the term denoting either an entrance or changes which are inserted into a
systemand which activate/modify a process. It is an abstract concept, used in the modeling, system(s) design and system(s) exploitation. It is usually connected with other terms, "e.g.", input field, input variable, input parameter, input value, input signal, input deviceand input file.
From the most general
systemicsperspective, input is a subjective concept and depends on how the system is used. In such sense, the same system can have different inputs in different applications.
In the case of a process description/model, input is closely connected with the concept
output. Here, what enters is called input and what exits is called output.
Example:For an abstract system "A(x,y,p)", where "x,y" are variables and "p" is a parameter, "x" may denote input (variable) and "y" may denote the output for a process: "y = f(p,x)", but, for another goal/(system application), the system "A" can be the
carrierof a process "x = g(p,y)", where "y" is an input and "x" is an output.Fact|date=February 2007
Usually, in the modeling of a problem/process, input are these variables which are known and output are those unknown to us yet.
In recognition that the quality of the input can be crucial to the value of the output, a famous saying teaches us "Garbage IN, Garbage OUT" (GIGO).
* [http://www.thefreedictionary.com/input Definitions of input] by the freedictionary.
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