But Robust Design or Robust Engineering is different. And it is not difficult to understand those strategies. In order to fight fires, make improvements or solve a particular problem, we tend to measure symptoms. Problems are symptoms of variability caused by noise factors. It is much more effective to measure function and to search for a design in which variability of function is minimized.
Function is an energy transformation.
To achieve robustness, we measure the energy transformation or something that represents energy transformation. Function is not scalar. It has infinite dimensions. For example, the function of machining is to remove material to generate a shape. A shape has infinite dimensions.