Hans-Paul Schwefel is a German
computer scientistA computer scientist is a scientist who has acquired knowledge of computer science, the study of the theoretical foundations of information and computation and their application in computer systems....
and professor emeritus at University of Dortmund (now Dortmund University of Technology), where he held the chair of
systems analysisSystems analysis is the study of sets of interacting entities, including computer systems analysis. This field is closely related to requirements analysis or operations research...
from 1985 until 2006. He is one of the pioneers in
evolutionary computationIn computer science, evolutionary computation is a subfield of artificial intelligence that involves combinatorial optimization problems....
and one of the authors responsible for the evolution strategies (
Evolutionsstrategien). His work has helped to understand the dynamics of evolutionary algorithms and to put evolutionary computation on formal grounds.
He attended the
Technical University of BerlinThe Technische Universität Berlin is a research university located in Berlin, Germany. Translating the name into English is discouraged by the university, however paraphrasing as Berlin Institute of Technology is recommended by the university if necessary .The TU Berlin was founded...
(TUB) and graduated as an aerospace engineer in 1965 and got his Dr.-Ing. in 1975. While as a student at TUB, he met
Ingo RechenbergIngo Rechenberg is a German computer scientist and professor. Rechenberg is a pioneer of the fields of evolutionary computation and artificial evolution. In the 1960s and 1970s he invented a highly influential set of optimization methods known as evolution strategies...
in November 1963. Both of them were studying the aero- and space technology and both of them were keen on
cyberneticsCybernetics is the interdisciplinary study of the structure of regulatory systems. Cybernetics is closely related to information theory, control theory and systems theory, at least in its first-order form...
and
bionicsBionics is the application of biological methods and systems found in nature to the study and design of engineering systems and modern technology.The word bionic was coined by Jack E...
. Rechenberg was dealing with wall shear stress measurements and Schwefel was responsible for organizing fluid dynamics exercises for other students. Together they were dreaming of a research robot working according to cybernetic principles, but computers became available only later on.
While attending the
Hermann Föttinger-Institute for Hydrodynamics (HFI) at TUB, he and Rechenberg began performing experiments upon
wingA wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...
s, kinked plates, and other objects related to
fluid dynamicsIn physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...
. The main objective of those experiments concerned optimizing the shape and/or parameters through mostly small modifications on the real objects, a "technique" they called
experimental optimization, in order to reduce the
dragIn fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...
, increase the
thrustThrust is a reaction force described quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a force of equal magnitude but opposite direction on that system....
, and so on. Applying classical optimization methods (such as Gauss–Seidel and
gradientIn vector calculus, the gradient of a scalar field is a vector field that points in the direction of the greatest rate of increase of the scalar field, and whose magnitude is the greatest rate of change....
-based techniques) on such experiments showed that those methods are not well suited to be adopted in
experimental optimization, mainly due to noisy measurements and/or multimodality. They realized modifying all the variables at same time via a random manner (e.g., small modifications are more frequent than larger ones). This was the seminal idea to bring to light the first, two membered,
evolution strategyIn computer science, evolution strategy is an optimization technique based on ideas of adaptation and evolution. It belongs to the general class of evolutionary computation or artificial evolution methodologies.-History:...
, which was initially used on a discrete problem (optimization of a kinked plate in a wind tunnel) and was handled without computers.
Some time later, Schwefel expanded the idea toward evolution strategies to deal with numerical/parametric optimization and, also, has helped to formalize it as it is known nowadays.
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