Accuracy
The correctness of a value with respect to absolute truth. See also tolerance and precision.
Analog Computer
A computational device that models (often differential) equations as an electrical circuit and, therefore, requiring all problems to be recast in the form of circuit design. For the most part, analog computers have been replaced by digital computers, but idea was exceedingly cool, and wonderful things could be accomplished with it.
Evaluate
In the System Engineering context, the process of specifying the actual collection of points for a value, rather than the criteria for their selection. The abstraction is borrowed from database design theory.
Experimental Uncertainty
There being no such thing as a perfect measurement, Experimental Uncertainty expresses the result of analytically propagating measurement “errors”1 from the instrument to a final, integrated result. Propagation is often not simple, and often depends on the detailed physics relationship between properties than can be instrumented and properties that cannot be instrumented. The National Institute of... read more
Factor
(n) A dimensionless quantity which, when multiplied by to some other quantity, accommodates uncertainties in knowing the value of that other quantity. Contrast with margin. (v) To decompose a parameter into subordinate parameters by means of some defining relationship (e.g., an equation).
Functional Analysis
1. In mathematics: the abstract study of characteristic properties possessed by different classes of mathematical functions. 2. In Systems Engineering a. The prescriptive process of decomposing functions into smaller functions. b. The descriptive process of identifying functions performed by some existing system or item. 2.b is the original sense of the term in System Engineering, used... read more
Functional Decomposition
A decomposition process executed in the functional domain. The completeness criterion is to show that the sub-functions (“child functions”) effect the state change (or maintenance) that spans the function being decomposed (“parent function”). Re-parameterization of the system’s state vector is an acceptable means of demonstrating completeness, provided that the re-parameterization is at-least-locally1 deterministic2 in both... read more