164 research outputs found
Split Bregman Method for Sparse Inverse Covariance Estimation with Matrix Iteration Acceleration
We consider the problem of estimating the inverse covariance matrix by
maximizing the likelihood function with a penalty added to encourage the
sparsity of the resulting matrix. We propose a new approach based on the split
Bregman method to solve the regularized maximum likelihood estimation problem.
We show that our method is significantly faster than the widely used graphical
lasso method, which is based on blockwise coordinate descent, on both
artificial and real-world data. More importantly, different from the graphical
lasso, the split Bregman based method is much more general, and can be applied
to a class of regularization terms other than the nor
5-Bromo-2-methylÂpyridine N-oxide
In the molÂecule of the title compound, C6H6BrNO, the methyl C and oxide O atoms lie in the pyridine ring plane, while the Br atom is displaced by 0.103 (3) Å. In the crystal structure, interÂmolecular C—H⋯O hydrogen bonds link the molÂecules into centrosymmetric dimers
Methyl 4-chloro-3-nitroÂbenzoate
In the title compound, C8H6ClNO4, the molÂecules are linked by C—H⋯O interÂactions to form a chain parallel to the a axis. The chains are further connected by slipped π–π stacking between symmetry-related benzene rings, with a centroid-to-centroid distance of 3.646 (2) Å and an interÂplanar distance of 3.474 Å, resulting in an offset of 1.106 Å
Model Seleksi Premi Asuransi Jiwa Dwiguna untuk Kasus Multiple Decrement
This article discusses a select survival model for the case of multiple decrements in evaluating endowment life insurance premium for person currently aged ( + ) years, who is selected at age with â„Ž years selection period. The case of multiple decrements in this case is limited to two cases. The calculation of the annual premium is done by prior evaluating of the single premium, and the present value of annuity depends on theconstant force assumption
An Updated Search of Steady TeV Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array
Using the data taken from Tibet II High Density (HD) Array (1997
February-1999 September) and Tibet-III array (1999 November-2005 November), our
previous northern sky survey for TeV ray point sources has now been
updated by a factor of 2.8 improved statistics. From to
in declination (Dec) range, no new TeV ray point
sources with sufficiently high significance were identified while the
well-known Crab Nebula and Mrk421 remain to be the brightest TeV ray
sources within the field of view of the Tibet air shower array. Based on the
currently available data and at the 90% confidence level (C.L.), the flux upper
limits for different power law index assumption are re-derived, which are
approximately improved by 1.7 times as compared with our previous reported
limits.Comment: This paper has been accepted by hepn
- …