Subjective Logic Operators Demo

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Subjective Logic takes opinion arguments which can be binomial or multinomial. A binomial opinion about a proposition is an ordered quadruple (b,d,u,a) where:
b: belief is the belief that the proposition is true.
d: disbelief is the belief that the proposition is false.
u: uncertainty is belief that is neither committed to truth nor falsehood of the proposition.
a: base rate is the a priori probability of the proposition in the absence of specific belief. The default value is the relative atomicity, i.e. 0.5 for a binary state space containing the proposition and its complement.
The belief, disbelief and uncertainty components satisfy b+d+u=1 Opinions where b+d=1 are traditional probabilities, opinions where 0<(b+d)<1 express degrees of ignorance, and opinions where b+d=0 express total ignorance. The projected probability of a binomial opinion is defined as P=b+au. See the book on subjective logic or the subjective logic on Wikipedia page for more details. See also the opinion visualisation demo, and the trust network demo that uses the fusion and trust transitivity operators for analysing trust networks.

Opinions can be visualized on opinion triangles. A blue point represents a (b,d,u) triple. The b,d,u-axes run from one side to the opposite vertex indicated by the letters b, d and u. For example, a strong positive opinion is represented by a point towards the bottom right b-vertex. The base rate, also called relative atomicity, is shown as a pointer along the base line, and the projected probability, P, is formed by projecting the opinion onto the base, parallel to the base rate `projector' line.

Try subjective logic operators in action below. Select one of the operators at the top left of the frame below. Left-click and drag the opinion points and the base rate pointers on the left triangles to set the argument opinions. The computed result opinion is represented on the right-most triangle.

JavaScript design by Gaëtan Bouguier.


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Last updated: 7 July 2017.