Dempster-Shafer Theory SIU CS 537 4/12/11 and 4/14/11 Chet Langin
Dempster, A. P. (1967). "Upper and Lower Probabilities Induced by a Multivalued Mapping.“ The Annals of Mathematical Statistics 38(2): Shafer, G. (1976). A Mathematical Theory of Evidence, Princeton University Press.
What is Dempster-Shafer? Dempster-Shafer (D-S or DS) Mathematical theory of evidence. Data fusion. Degree of belief. Generalization of Bayes theory. Sets. Mass, not probability. “Bel Function” – Belief function
The D-S Environment
D-S Environment, Cont.
D-S vs. Probability
Non-belief vs. Ignorance
D-S Mass
Combining Evidence
D-S Rule of Combination
Example Combination Bomber = = 0.90 Bomber or Fighter = 0.07 Non-belief = 0.03
Range of Belief
What Would Make Plausibility < 1?
Evidential Interval
Example Evidential Intervals [1, 1]Completely True [0, 0]Completely False [0, 1]Completely Ignorant [Bel, 1]Tends to support [0, Pls]Tends to refute [Bel, Pls]Tends to both support & refute
Bel vs. Bel()
Bel() Example
Combination of 2 Bel()
The Normalization of Belief
A New Table
Normalization
Normalization, Cont. OK!
New Evidential Interval Belief | Plausibility | Disbelief Belief | Plausibility