Počet záznamů: 1

A geometric view on learning Bayesian network structures

  1. 1.
    0342804 - UTIA-B 2011 RIV US eng J - Článek v odborném periodiku
    Studený, Milan - Vomlel, Jiří - Hemmecke, R.
    A geometric view on learning Bayesian network structures.
    International Journal of Approximate Reasoning. Roč. 51, č. 5 (2010), s. 578-586 ISSN 0888-613X.
    [PGM 2008]
    Grant CEP: GA AV ČR(CZ) IAA100750603; GA MŠk(CZ) 1M0572; GA ČR GA201/08/0539
    Grant ostatní: GA MŠk(CZ) 2C06019
    Výzkumný záměr: CEZ:AV0Z10750506
    Klíčová slova: learning Bayesian networks * standard imset * inclusion neighborhood * geometric neighborhood * GES algorithm
    Kód oboru RIV: BA - Obecná matematika
    Impakt faktor: 1.679, rok: 2010
    http://library.utia.cas.cz/separaty/2010/MTR/studeny-0342804.pdf http://library.utia.cas.cz/separaty/2010/MTR/studeny-0342804.pdf

    Basic idea of an algebraic approach to learning Bayesian network (BN) structures is to represent every BN structure by a certain (uniquely determined) vector, called a standard imset. The main result of the paper is that the set of standard imsets is the set of vertices of a certain polytope. Motivated by the geometric view, we introduce the concept of the geometric neighborhood for standard imsets, and, consequently, for BN structures. Then we show that it always includes the inclusion neighborhood}, which was introduced earlier in connection with the GES algorithm. The third result is that the global optimum of an affine function over the polytope coincides with the local optimum relative to the geometric neighborhood. The geometric neighborhood in the case of three variables is described and shown to differ from the inclusion neighborhood. This leads to a simple example of the failure of the GES algorithm if data are not ``generated" from a perfectly Markovian distribution.
    Trvalý link: http://hdl.handle.net/11104/0185432