More Mini Essays [From the Editor]

In many disciplines, such as circuits and fluids, the goal is to model and simulate to better understand the real world. In control, our goal is to interact with the real world to make it do something other than what it might normally wish to do. This interaction requires that we keep careful track of what we know and don´t know. For example, we know that a rigid body has an inertia matrix, but we realize that we may not know it precisely. To keep track of this distinction, we learn through experience in the controls field to make a mental note of the status of each quantity that we write down. But it occurred to me that a simple technique might make our papers easier to understand.