SYSTEMS-ANALYSIS, SYSTEMS-DESIGN, AND EVOLUTIONARY STRATEGIES

(Formal) modelling, (computer) simulation, and (numerical) optimization are the main tools of Systems Analysis. Without the bracketed adjectives these three phases always have been used for preparing individual operations mentally: Analysing (in the narrow sense) the current situation with its interdependencies between crucial variables, scenario writing or imagining the probable consequences of possible actions, and selecting that alternative which seems to be the most attractive one. Our brain is a wonderful means to perform such a task, even in rather difficult situations and even rather quickly, but with limited accuracy and only as long as the number of variables is very small. If there are many highly interdependent variables, if there are nonlinearities, and if longer time horizons have to be considered dynamically, then an individual brain in most cases is overtaxed. Today we have to deal with such complex tasks not only individually but collectively, but we do not have a natural super-brain. We may, however, use 'artificial' ones: computers. Now the bracketed adjectives come into the play. What has been achieved on that basis and where still are missing links, shall be the subject of this paper.