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.


HUB 1)2)

A node in a network linked with many other nodes.

Hubs are important because they ease long distance communication in the network by reducing the number of intermediate steps needed to connect any node with any other one.

(see "small world") Each hub becomes a concentration and distributive center for information in the network and contributes to its structuration. Hubs are a basic feature, specially in Internet to which they provide innumerable short cuts, simplifying and accelerating communication. Thus, hubs are not merely static elements, but are also basic in dynamics.

Hubs can be found in many different classes of networks. D. COHEN for ex., writes: "Food webs – the networks of who eats whom in various ecosystems – are built around "hub species" that eat large number of different prey species…" (D. COHEN, 2002). Hubs are also basic in human societies: A scientific journal, for instance, can be considered a hub for the world diffusion of specific information, among widely separated groups working on related subjects.

Also, in the propagation of epidemics, some individuals, in particular promiscuous ones in the case of AIDS, may be viewed as hubs, who can easily created new foci in very distant places. Cohen even writes: "… the way HIV spreads through populations is similar to the spread of viruses on the Net". Hubs are also important in graphs used in social psychology to describe interpersonal relationships within and among groups. In short, hubs are all-important in terms of multiple social interconnections of any kind.

As a basic organization feature, hubs are also somehow related to ASHBY's constraints.

The number of hubs in a network is related to the number of nodes by a power law: there are much less hubs than common nodes and the most connected hubs are also the less frequent ones (See D. WADS, 1999).

An unfortunate feature of highly connected hubs is that their accidental or wilful destruction, sometimes at one stroke, can impair or even destroy the whole network. Examples are widespread blackouts in interconnected electrical grids, or extensive functional impairment as a result of a cerebral haemorrhage

The notion of Hub has been considered in its most general sense by A.L. BARABASI (2002).

The word "neurode"is used in a quite closely related meaning.


  • 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).

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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