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.

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ALGORITHM (Back propagation) 5)

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A procedure to compute the errors resulting of the activity (EA) level of a unit in a neuronal computer net (i.e. the difference between the actual and the desired output), and to correct accordingly the corresponding error weights (EW).

In a neuron which processes signals (= activities) each input is multiplied by a number called the weight. The sum of the weights, as computed by the neuron, determines the output of the neuron through an input-output function

If the output differs from the desired activity, i.e. when there is an error in activity (EA), this error is calculated as "the square of the difference between the actual and the desired activities", as stated by G. HINTON.

The weights are then modified in order to reduce the error in activity.

The back-propagation algorithm – invented around 1974 by P. WERBOS – is thus basically a feedback process.

In HINTON's words, "The back-propagation algorithm is easiest to understand if all the units in the network are linear… For nonlinear units, the back-propagation algorithm includes an extra step. Before back-propagating, the EA must be converted into the EI, the rate at which the error changes as the total input received by a unit is changed". (1992, p.106)

This corrective mechanism is iterative (see below)

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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