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

PERCOLATION 2)

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Propagation mode of a process in a medium or a relatively homogeneous system, characterized by a sudden discontinuity at some precise instant, depending on a critical density of the main component in that medium or system.

In random graphs used as models "… percolation thresholds occur… and determine when large, connected webs of elements will form. Below the threshold, such webs do not form; above the threshold, they do" (S. KAUFFMAN, 1993, p.205).

This is a dynamics of contagion and apply only to almost homogeneous systems. The concept was introduced by the English mathematician J.M. HAMMERSLEY in 1956, and corresponds to a general model which permits a better understanding of numerous phenomena, as for example:

- epidemics and epizootics

- forest and bush fires

- pest invasions in fields and orchards

- mud or rock slides, or snow avalanches

- the triggering phase of numerous chemical processes

On this side of a defined density of the principal component of the system or medium, the process remains confined and cannot propagate itself to the whole system.

P. GRASSBERGER, using the example of a specific pest invasion in an orchard planted with various kinds of trees, observes that: "One may ask oneself if the chances of a pest to invade one by one all of the apple trees do increase regularly with the proportion of apple trees…

"Such is not the case. Quite surprisingly, the pests chances to run from one to the other extremity of the orchard are practically nil under a certain proportion of apple trees but become practically 100% over that value…

"Percolation functions are like an "all or nothing process" (1991, p.640).

Of course, it is implied that no perturbing factor does interfere. The situation would by quite different if a strong wind should transport the insects far away (see "Oriented percolation") or if the affected population members would be able to travel at great distances.

Categories

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

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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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