1. "A measure of the degree of connectedness of a system" (W.R. ASHBY & M.R. GARDNER, 1970, in ASHBY, 1981, p.85-87).
This definition is very close to T.F.H. ALLEN and T.B. STARR's definition of connectance.
ALLEN and STARR state that "connectance":"… is usually expresed as a percentage: the percentage of nonzero interaction terms as a percentage of all possible interaction terms, reasonable or otherwise, between the components of a system" (1982, p.264).
Systemics, as a transdisciplinary methodology of models, offers a high degree of connectivity, allowing for example for satisfactory links of biology and psychology within social theory (P. HEJL, 1985, p.112).
2. The global character of a network or system whose elements are interrelated to some defined degree.
Composite systems have a very low degree of connectivity – which anyhow is sufficient to subsume some collective and more or less periodical behavior, as for example avalanches. However, strong integration is the result of a higher degree of connectivity.
ASHBY expressed the idea that a system should have a minimum of connectivity (i.e. must be more or less "joined") if it is to perform some definite functions. However, an excess of connectivity (in too "strongly joined" systems) leads to behavioral rigidity and loss of adaptiveness.
St. KAUFFMAN distinguishes "solid", "liquid" or "gaseous" phases in networks, corresponding to the more or less numerous presence of what he calls "frozen cores".(1992, p.67). This can be considered as equivalent to a measure of connectivity.
Connectivity can be easily modelized by graphs, which may represent local connectivities of some elements and more global ones between these local clusters. It is a fine way to obtain a visual understanding of a network. (see for instance S. KAUFFMAN, 1993, p.420 and 490). This author also study the "connectivity properties of random graphs (which) exhibit phase transitions" (p.307 -10).
3. In the formal model of a system, the property which makes possible for the effects to be transmitted throughout the system (R. RODRIGUEZ ULLOA, 1994, p.136)
The author states: "Connectivity can be physical as for ex. in a system of order and delivery processing, or be an information flow (verbal), or a flow of energy or influences (Ibid).
- 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). 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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