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Geometry of Dempster's rule of combination |
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Fabio Cuzzolin
IEEE Transactions on Systems, Man, and Cybernetics - part B, 34(2), pages 961- 977, April 2004 |
| Abstract |
In this paper, we analyze Shafer’s belief functions
(BFs) as geometric entities, focusing in particular on the geometric
behavior of Dempster’s rule of combination in the belief space, i.e.,
the set of all the admissible BFs defined over a given finite
domain Theta. The study of the orthogonal sums of affine subspaces
allows us to unveil a convex decomposition of Dempster’s rule of
combination in terms of Bayes’ rule of conditioning and prove that
under specific conditions orthogonal sum and affine closure commute.
A direct consequence of these results is the simplicial shape
of the conditional subspaces , i.e., the sets of all the possible combinations
of a given BF s. We show how Dempster’s rule exhibits a rather elegant behavior
when applied to BFs assigning the same mass to a fixed subset
(constant mass loci). The resulting affine spaces have a common intersection
that is characteristic of the conditional subspace, called
focus. The affine geometry of these foci eventually suggests an interesting
geometric construction of the orthogonal sum of two BFs. |
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| BibTeX Entry |
@article{cuzzolin04smcb,
AUTHOR = "Fabio Cuzzolin",
TITLE = "Geometry of Dempster's rule of combination",
JOURNAL = "IEEE Transactions on Systems, Man, and Cybernetics - part B",
VOLUME = "34",
NUMBER = "2",
PAGES = "961--977",
YEAR = "2004"
} |
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