Closing loops : a unified view from control to information science

The application of feedback mechanism to technical systems is one the most important steps improving the dynamics of technical systems and also to realize new technical solutions. The dynamical behavior of technical systems is considered without and with control, conditions are calculated improving vibrational behaviour first of SISO, since the sixties also of MIMO systems. New mathematical approaches are used to examine the structural inner connections between the system itself and also from the input and to the output. In all of these cases physical values on the input and output side are considered as signals equal to functions of time. Mathematical equations (like ODE/PDE or DAE) are ususally used to describe the I/O behaviour. With the same roots, information scientific approaches are developed in the last 60 years. The objects of information science approaches are data in various pure and combined variations, but mainly numbers. The common root is founded by Wiener (6) and others. Inspired by the success of computing machines, Wiener regrets the feedback mechanism and combines this with algorithms realized on computing machines and thoughts about self-organizing and -optimizing systems (like closed-loop systems are self-optimizing systems with respect to the dynamic behaviour of the output). This gives the new scientific community the name used for over 20-30 years: cybernetics. The mathematical core of this new science focused to technical applications based on mathematics: control and control theory. Up to the eighties this area is growing and several new applications demonstrate daily the success of this ideas. The development of computers, the increasing memory capabilities, the processing speed but especially the success in software technologies decouples the development of applied information science from those of control techniques.