The term "variable system" is correct and usable in written English.
You can use it to refer to a system in which some of the parts, elements, or variables can change or vary. For example, "The company is switching to a new variable system that will allow them to more easily adjust to market demands."
But you have to accept that we are in the centre of a very variable system.
Frederick Stumm, author of the 1998 study, said additional research is needed because a recent survey of the area found a "very complicated and variable system".
It's applied to single control variable system, such as inverted pendulum.
The idea is that something nonintuitive occurs when any randomly fluctuating weak signal -- the scientific term is "noise" -- is fed into any highly variable system like a changing climate or a heavy person tottering on skinny legs.
Commuters, school-run parents and motorway users would bear the brunt of a variable system, where charges would be highest for rush-hour travel and for using the most congested roads.
When the Toronto-based graphic designer Bruce Mau created a new identity for the Netherlands Architecture Institute in 1993, he devised an infinitely variable system of 100 versions of the same logo in 1,000 different colors.
This would be a time-variable system of education rooted in the outcomes or competencies students are expected to achieve.
A SAH system is a multi-variable system that is hard to model by conventional methods.
Here, we compare the dynamical behaviour of the full four-variable system with its two-variable counterpart.
An SOFC stack is a nonlinear and multi-variable system which is difficult to model by traditional methods.
For this strict-feedback form of multi-variable system, dynamic surface control algorithm is implemented combining with extended observer (ESO) to complete the preliminary design.
