A qualitative commonsense method for optimization of complex engineering systems

A commonsense approach to optimization is needed especially during the early stages of research and design projects. A qualitative interpretation of classical optimization is used to formalize and systematize commonsense. The qualitative algebra can use only three different values (¸+, ¸0,¸-). The degradation of conventional models (objective functions, constraints) eliminates the need for numerical values of constants. The result of qualitative optimization is a list of all possible behaviours (scenarios). Therefore the complete list of all possible ways of increasing or decreasing objective functions are identified. Two problems, the linear optimization of safety improvements and the nonlinear optimization of anaerobic fermentation are presented.