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.


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 fixed set of sampling elements" (G. KLIR, 1967, p.194).

The mask is a partialized screen through which we observe specified states of the system. It is a kind of variety reductor. According to KLIR, he borrowed the term from A. SVOBODA (1963, 1964).

The concept is related to KLIR's "Behavior system", which "is defined by a time-invariant relation among selected present, past or future states of the variables in the experimental frame" (1988, p. 151).

The mask operates as a conceptual and formal selector.

It is an important tool of KLIR's systems inquiring method and reconstructability analysis.

KLIR describes the mask as follows: "The pattern of samples which is referred to as the mask, specifies those past, present or future states of the variables which are required to be a part of each sample. As such, the mask represents an hypothetical memory structure of the system" (1975, p.155).

KLIR moreover explains: "The problem of processing a given activity is related to a chosen mask (the mask represents something like the width of our view of the system) and may be stated as follows: Find samples of activity for all possible time positions of the chosen mask on the activity; express the relation between sampling variables, given by the obtained set of samples of activity, in the form of a Boolean equation, and solve the equation" (1967 p.194).

(for formalized aspects of the method see quoted papers)

As observed by M. NOWAKOWSKA: "The observer's first choice is to define operationally the phenomenon which he studies. This choice depends on the goal of research, and even for the same goal, the choice need not be unique". And: "… for the same goal, two researchers are likely to choose different variables. Whether or not the selected variables "cover" the phenomenon, in the sense that they provide information sufficient to attain the goal, is usually impossible to determine a priori with full certainty" (1986, p.62).

On the other hand: "Often the mask becomes changed in the process of taking the observations, i.e. one may decide to take some additional observations, of new variables, or of the variables observed until a given time" (p.66).

In other words, the choice and use of masks is partly heuristic and partly experimental.


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


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

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