46 research outputs found

    On semidefinite bounds for maximization of a non-convex quadratic objective over the ℓ1 unit ball

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    We consider the non-convex quadratic maximization problem subject to the ℓ1 unit ball constraint. The nature of the l1 norm structure makes this problem extremely hard to analyze, and as a consequence, the same difficulties are encountered when trying to build suitable approximations for this problem by some tractable convex counterpart formulations. We explore some properties of this problem, derive SDP-like relaxations and raise open questions. © EDP Sciences 2006

    The role of duality in optimization problems involving entropy functionals with applications to information theory

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    We consider infinite-dimensional optimization problems involving entropy-type functionals in the objective function as well as as in the constraints. A duality theory is developed for such problems and applied to the reliability rate function problem in information theory.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45233/1/10957_2004_Article_BF00939682.pd

    Low incidence of SARS-CoV-2, risk factors of mortality and the course of illness in the French national cohort of dialysis patients

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    Grouping multidimensional data : recent advances in clustering

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    xii, 268 p. : ill. ; 25 cm

    A dual approach to multidimensional L<sub>p</sub> spectral estimation problems

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    A complete duality theory is presented for the multidimensional L<sub>p</sub> spectral estimation problem. The authors use a new constraint qualification (BWCQ) for infinite-dimensional convex programs with linear type constraints recently introduced in [Borwein and Wolkowicz, Math. Programming, 35 (1986), pp. 83-96]. This allows direct derivation of the explicit optimal solution of the problem as presented in [Goodrich and Steinhardt, SIAM J. Appl. Math., 46 (1986), pp. 417-426], and establishment of the existence of a simple and computationally tractable unconstrained Lagrangian dual problem. Moreover, the results illustrate that (BWCQ) is more appropriate to spectral estimation problems than the traditional Slater condition (which may only be applied after transformation of the problem into an L<sub>p</sub> space [Goodrich and Steinhardt, op. cit.] and which therefore yields only necessary conditions)

    Measures of Dispersion and Cluster-Trees for Categorical Data

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