BCSSS

International Encyclopedia of Systems and Cybernetics

2nd Edition, as published by Charles François 2004 Presented by the Bertalanffy Center for the Study of Systems Science Vienna for public access.

About

The International Encyclopedia of Systems and Cybernetics was first edited and published by the system scientist Charles François in 1997. The online version that is provided here was based on the 2nd edition in 2004. It was uploaded and gifted to the center by ASC president Michael Lissack in 2019; the BCSSS purchased the rights for the re-publication of this volume in 200?. In 2018, the original editor expressed his wish to pass on the stewardship over the maintenance and further development of the encyclopedia to the Bertalanffy Center. In the future, the BCSSS seeks to further develop the encyclopedia by open collaboration within the systems sciences. Until the center has found and been able to implement an adequate technical solution for this, the static website is made accessible for the benefit of public scholarship and education.

A B C D E F G H I J K L M N O P Q R S T U V W Y Z

PERIODICITY 1)2)

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The more ore less regularly recurrent and more or less similar variations of a function or a systems behavior.

Periodicity implies a succession of cycles of regular or irregular frequencies and amplitudes. The following types of periodicities could be distinguished:

- mono-cyclical: corresponding to only one cycle of defined frequency and amplitude. Such periodicity is perfectly predictable. In many cases, when others cycles with very short or very long frequencies and amplitude are present, they escape observation for long time, or they seem to be trends and the mono-cyclical model remains generally adequate.

- commensurable, bi- or poly-cyclical: this case corresponds to the interferences and combinations of cycles of various commensurable frequencies in harmonic relation in phase or out of phase (f.ex. 2, 3. and 6 or, more complicated, 9, 12, 27). Such periodicities are still regular and predictable, but more intricated, difficult to observe and complicated to analyse. In some cases, fractal periodicities can be found. See: "Self-similarity in WEIERSTRASS functions".

- uncommensurable: This case corresponds to the interferences of various cycles with frequencies corresponding to prime numbers. In simple cases (f. ex. 2, 3, 5, and 7), observation and predictability seems still more or less manageable, using lowest common multiples (here, 210). However, for compositions of more, or greater prime numbers, regularities may become practically unobservable and the system may appear chaotic, i.e. globally deterministic only in the very long term and this merely in case of absence of any environmental perturbation.

Categories

  • 1) General information
  • 2) Methodology or model
  • 3) Epistemology, ontology and semantics
  • 4) Human sciences
  • 5) Discipline oriented

Publisher

Bertalanffy Center for the Study of Systems Science(2020).

To cite this page, please use the following information:

Bertalanffy Center for the Study of Systems Science (2020). Title of the entry. In Charles François (Ed.), International Encyclopedia of Systems and Cybernetics (2). Retrieved from www.systemspedia.org/[full/url]

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