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i.e. adaptation to a fixed environment (in this case, the adaptive system operates in a
way that to perform its functions in a given environment in the best way, trying to
maximize some performance criteria, e.g. effectiveness of functioning in a given envi-
ronment) and active adaptation, i.e. search for an environment adequate to the given
system (when change in the environment occurs in order to maximize the performance,
or active search for an environment is required in which the desired result to be
achieved). In both cases, two engineering aspects need to be considered to understand
adaptation as a process, i.e. the purpose of adaptation, that is, when and how it is defined
for the effective functioning of the system; and the adaptation algorithm, that is, in what
way is the final goal to be achieved. So far, setting the goal and the way to achieve it
are to define adaptation as a process. This means that adaptation refers to the manage-
ment in complex environment defining the process of changing the parameters and
structure of the system, and possibly the control actions based on current information
with the aim of achieving a certain, usually optimal state of the system with initial un-
certainty and changing working conditions [12]. It clearly defines the optimization re-
quirement for a given criterion, however, in most cases the complex systems do not
have a single criterion for functioning. Such systems operate in an environment wherein
multi criteria define the nature of restrictions, thus selection of adaptation criteria is
already an adaptive process itself and should be taken into account when determining
adaptation. In other words, taking into account the features of complex systems, adap-
tation in the broad sense can be defined as a process of purposefully changing the pa-
rameters and structure of the system, which consists in determining the criteria for its
functioning and fulfilling these criteria. Therefore, the problem of adaptation in tech-
nology is considered mainly using at least two ways - by choosing a successful adapta-
tion algorithm with a fixed criterion and by successfully varying the criteria with a fixed
adaptation algorithm.