Results 1  10
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2,307
Variable Selection via Nonconcave Penalized Likelihood and its Oracle Properties
, 2001
"... Variable selection is fundamental to highdimensional statistical modeling, including nonparametric regression. Many approaches in use are stepwise selection procedures, which can be computationally expensive and ignore stochastic errors in the variable selection process. In this article, penalized ..."
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Cited by 948 (62 self)
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functions are symmetric, nonconcave on (0, ∞), and have singularities at the origin to produce sparse solutions. Furthermore, the penalty functions should be bounded by a constant to reduce bias and satisfy certain conditions to yield continuous solutions. A new algorithm is proposed for optimizing
The DileptonProduction Cross Section in Principal Value Resummation
, 1995
"... Using a recent calculation of the perturbative hard part for dilepton production that sums large threshold corrections to all orders in perturbative QCD, we compute the corresponding cross sections. The hard part has been evaluated using principal value resummation and contains all singular momentum ..."
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momentumdependent corrections. We also include a resummation of large Sudakov terms, which are independent of parton momenta. We give predictions for the dileptonmass distribution, the rapidity distribution and the rapidityintegrated Kfactor at fixedtarget energies and compare with various
Lassotype recovery of sparse representations for highdimensional data
 ANNALS OF STATISTICS
, 2009
"... The Lasso is an attractive technique for regularization and variable selection for highdimensional data, where the number of predictor variables pn is potentially much larger than the number of samples n. However, it was recently discovered that the sparsity pattern of the Lasso estimator can only ..."
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Cited by 250 (14 self)
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is relaxed. Even though the Lasso cannot recover the correct sparsity pattern, we show that the estimator is still consistent in the ℓ2norm sense for fixed designs under conditions on (a) the number sn of nonzero components of the vector βn and (b) the minimal singular values of design matrices
Hyperbolic Conservation Laws with Stiff Relaxation Terms and Entropy
 Comm. Pure Appl. Math
, 1992
"... We study the limiting behavior of systems of hyperbolic conservation laws with stiff relaxation terms. Reduced systems, inviscid and viscous local conservation laws, and weakly nonlinear limits are derived through asymptotic expansions. An entropy condition is introduced for N \Theta N systems that ..."
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Cited by 192 (8 self)
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that ensures the hyperbolicity of the reduced inviscid system. The resulting characteristic speeds are shown to be interlaced with those of the original system. Moreover, the first correction to the reduced system is shown to be dissipative. A partial converse is proved for 2 \Theta 2 systems. This structure
A Singular Evolutive Extended Kalman Filter For Data Assimilation In Oceanography
 Journal of Marine Systems
, 1996
"... In this work, we propose a modified form of the extended Kalman filter for assimilating oceanic data into numerical models. Its development consists essentially in approximating the error covariance matrix by a singular low rank matrix, which amounts in practice to making no correction in those dire ..."
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Cited by 107 (9 self)
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In this work, we propose a modified form of the extended Kalman filter for assimilating oceanic data into numerical models. Its development consists essentially in approximating the error covariance matrix by a singular low rank matrix, which amounts in practice to making no correction in those
Power corrections and Landau singularity
"... In the dispersive approach of Dokshitzer, Marchesini and Webber, standard powerbehaved contributions of infrared origin are described with the notion of an infrared regular QCD coupling. I argue that their framework suggests the existence of nonstandard contributions, arising from short distances ..."
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Cited by 2 (2 self)
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(hence unrelated to renormalons and the operator product expansion), which appear in the process of removing the Landau singularity of the perturbative coupling. A natural definition of an infrared finite perturbative coupling is suggested within the dispersive method. Implications for the tau hadronic
The Energy Dependence of the Saturation Momentum 1
, 2002
"... We study BFKL evolution and, in particular, the energy dependence of the saturation momentum in the presence of saturation boundaries limiting the region of linear BFKL evolution. In the case of fixed coupling evolution we confirm the previously found exponential term in Qs(Y) and determine the pref ..."
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We study BFKL evolution and, in particular, the energy dependence of the saturation momentum in the presence of saturation boundaries limiting the region of linear BFKL evolution. In the case of fixed coupling evolution we confirm the previously found exponential term in Qs(Y) and determine
The conical singularity and quantum corrections to entropy of black hole
 Phys. Rev. D
, 1995
"... For general finite temperature different from the Hawking one there appears a well known conical singularity in the Euclidean classical solution of gravitational equations. The method of regularizing the cone by regular surface is used to determine the curvature tensors for such a metrics. This allo ..."
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Cited by 23 (5 self)
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to be divergent logarithmically in two dimensions and quadratically in four dimensions that coincides with results obtained earlier. For the eternal 2D black hole we observe finite, dependent on the mass, correction to the entropy. The entropy of the 4D Schwarzschild black hole is shown to possess an additional
Height and gradient from shading
 International Journal of Computer Vision
, 1990
"... Abstract: The method described here for recovering the shape of a surface from a shaded image can deal with complex, wrinkled surfaces. Integrability can be enforced easily because both surface height and gradient are represented (A gradient field is integrable if it is the gradient of some surface ..."
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Cited by 135 (1 self)
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height function). The robustness of the method stems in part from linearization of the reflectance map about the current estimate of the surface orientation at each picture cell (The reflectance map gives the dependence of scene radiance on surface orientation). The new scheme can find an exact solution
Results 1  10
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2,307