Página 1 dos resultados de 590 itens digitais encontrados em 0.251 segundos

## Estudo do fenômeno da auto-intersecção em um anel anisotrópico; Study of the self-intersection anomaly in an anisotropic ring

García Sánchez, Jesús Antonio
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
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## Apreciação critica dos fundamentos da culpabilidade a partir da criminologia: contribuições para um direito penal mais ético; A critical appraisal of the foundations of culpability from a criminological perspetive: contributions to a more ethical criminal law.

Tangerino, Davi de Paiva Costa
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
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## Comment on the Letter by A. Ben-Shaul: “Entropy, Energy, and Bending of DNA in Viral Capsids”

Harvey, Stephen C.
Fonte: The Biophysical Society Publicador: The Biophysical Society
Tipo: Artigo de Revista Científica
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The conformational entropic penalty associated with packaging double-stranded DNA into viral capsids remains an issue of contention. So far, models based on a continuum approximation for DNA have either left the question unexamined, or they have assumed that the entropic penalty is negligible, following an early analysis by Riemer and Bloomfield. In contrast, molecular-dynamics (MD) simulations using bead-and-spring models consistently show a large penalty. A recent letter from Ben-Shaul attempts to reconcile the differences. While the letter makes some valid points, the issue of how to include conformational entropy in the continuum models remains unresolved. In this Comment, I show that the free energy decomposition from continuum models could be brought into line with the decomposition from the MD simulations with two adjustments. First, the entropy from Flory-Huggins theory should be replaced by the estimate of the entropic penalty given in Ben-Shaul’s letter, which corresponds closely to that from the MD simulations. Second, the DNA-DNA repulsions are well described by the empirical relationship given by the Cal Tech group, but the strength of these should be reduced by about half, using parameters based on the Rau-Parsegian experiments...

## Penas privativas de dignidade? : a função da pena pela teoria dos sistemas autopoiéticos; Dignity preservation penalties? : the function of the penalty by the theory of the autopoietic systems

Sampaio, André Rocha
Fonte: Universidade Federal de Alagoas; BR; Ciência Jurídica; Programa de Pós-Graduação em Direito; UFAL Publicador: Universidade Federal de Alagoas; BR; Ciência Jurídica; Programa de Pós-Graduação em Direito; UFAL
Tipo: Dissertação Formato: application/pdf
POR
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The Federal Constitution of 1988 has brought deep changes in the Brazilian juridical system, among them, we can emphasize the appearance of the value dignity of the human person as a fundament of the Democratic State of Law. Taking in account that almost the entire juridical rules of penal execution dates back of a moment before the promulgation of the new Constitution, it became important to analyze all the penitentiary system on the perspective of the human dignity. With the proposal of minimize ideological influences and use an analyses different from the Cartesian analyses, we used the approach of the autopoietic systems theory of Niklas Luhmann, having as a goal to demonstrate clearly the salient aspects that differs what the juridical system disposes from what is empirically noticed in the Brazilian penitentiary system.; ; A Constituição Federal de 1988 trouxe profundas alterações no sistema jurídico brasileiro, dentre elas o advento do axioma dignidade da pessoa humana como fundamento do Estado Democrático de Direito. Levando-se em consideração que quase todo regramento jurídico acerca da execução penal data de época anterior à promulgação da nova Carta Constitucional, revelou-se importante uma análise de todo o sistema penitenciário sob a ótica da dignidade humana. Com o propósito de minimizar influências ideológicas e nos utilizar de uma análise diversa da cartesiana...

## Análise do jogo de goalball : modelação e interpretação dos padrões de jogo da Paralimpíada de Pequim 2008; Match analysis in goalball : modelling and interpretation of the game standards in the Beijing 2008 Paralympic Games

Márcio Pereira Morato
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
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## A sanção penal entre o crime e o potencial criminoso : uma abordagem jurídico-econômico da pena

Matta, Marcelo Cabistani da
Tipo: Dissertação Formato: application/pdf
POR
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Essa dissertação tem como objetivo apresentar uma análise acerca do comportamento do delinqüente em relação ao quantum de pena previsto no Código Penal brasileiro, possuindo como fundamento a teoria economicista do crime e a legislação penal apresentada. Parte-se, em um primeiro momento, para uma explicação da evolução da sanção penal, destacando as teorias que explicam as finalidades das penas. Dá-se ênfase a dois grandes grupos teóricos: teorias absolutas da pena, que utilizam a pena como um juízo de reprovação/retribuição, e as teorias relativas da pena, que fazem da sanção penal um instrumento para impedir que novos crimes aconteçam (prevenção). Na seqüência, apresentase o modelo econômico básico do crime, desenvolvido por Becker (1968) e seus fundamentos teóricos em Beccaria (1764), em Bentham (1781) e na teoria da escolha racional. Esclarece-se que o modelo economicista do crime enquadra-se entre as teorias relativas da pena (prevenção). Ressalta-se que o instituto da pena é um dos principais mecanismos que o Estado possui para alterar o comportamento de potenciais infratores. Explica-se que o sistema criminal brasileiro estabelece como finalidade da pena tanto a reprovação quanto a prevenção. No entanto...

## Strong consistency of the maximum likelihood estimator for finite mixtures of location-scale distributions when penalty is imposed on the ratios of the scale parameters

Tanaka, Kentaro
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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In finite mixtures of location-scale distributions, if there is no constraint or penalty on the parameters, then the maximum likelihood estimator does not exist because the likelihood is unbounded. To avoid this problem, we consider a penalized likelihood, where the penalty is a function of the minimum of the ratios of the scale parameters and the sample size. It is shown that the penalized maximum likelihood estimator is strongly consistent. We also analyze the consistency of a penalized maximum likelihood estimator where the penalty is imposed on the scale parameters themselves.; Comment: 29 pages, 2 figures

## The LASSO for generic design matrices as a function of the relaxation parameter

Chretien, Stephane; Darses, Sebastien
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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The LASSO is a variable subset selection procedure in statistical linear regression based on $\ell_1$ penalization of the least-squares operator. Its behavior crucially depends, both in practice and in theory, on the ratio between the fidelity term and the penalty term. We provide a detailed analysis of the fidelity vs. penalty ratio as a function of the relaxation parameter. Our study is based on a general position condition on the design matrix which holds with probability one for most experimental models. Along the way, the proofs of some well known basic properties of the LASSO are provided from this new generic point of view.

## Asymptotic optimality and efficient computation of the leave-subject-out cross-validation

Xu, Ganggang; Huang, Jianhua Z.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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Although the leave-subject-out cross-validation (CV) has been widely used in practice for tuning parameter selection for various nonparametric and semiparametric models of longitudinal data, its theoretical property is unknown and solving the associated optimization problem is computationally expensive, especially when there are multiple tuning parameters. In this paper, by focusing on the penalized spline method, we show that the leave-subject-out CV is optimal in the sense that it is asymptotically equivalent to the empirical squared error loss function minimization. An efficient Newton-type algorithm is developed to compute the penalty parameters that optimize the CV criterion. Simulated and real data are used to demonstrate the effectiveness of the leave-subject-out CV in selecting both the penalty parameters and the working correlation matrix.; Comment: Published in at http://dx.doi.org/10.1214/12-AOS1063 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org)

## Nearly unbiased variable selection under minimax concave penalty

Zhang, Cun-Hui
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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We propose MC+, a fast, continuous, nearly unbiased and accurate method of penalized variable selection in high-dimensional linear regression. The LASSO is fast and continuous, but biased. The bias of the LASSO may prevent consistent variable selection. Subset selection is unbiased but computationally costly. The MC+ has two elements: a minimax concave penalty (MCP) and a penalized linear unbiased selection (PLUS) algorithm. The MCP provides the convexity of the penalized loss in sparse regions to the greatest extent given certain thresholds for variable selection and unbiasedness. The PLUS computes multiple exact local minimizers of a possibly nonconvex penalized loss function in a certain main branch of the graph of critical points of the penalized loss. Its output is a continuous piecewise linear path encompassing from the origin for infinite penalty to a least squares solution for zero penalty. We prove that at a universal penalty level, the MC+ has high probability of matching the signs of the unknowns, and thus correct selection, without assuming the strong irrepresentable condition required by the LASSO. This selection consistency applies to the case of $p\gg n$, and is proved to hold for exactly the MC+ solution among possibly many local minimizers. We prove that the MC+ attains certain minimax convergence rates in probability for the estimation of regression coefficients in $\ell_r$ balls. We use the SURE method to derive degrees of freedom and $C_p$-type risk estimates for general penalized LSE...

## Choosing a penalty for model selection in heteroscedastic regression

Arlot, Sylvain
Tipo: Artigo de Revista Científica
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We consider the problem of choosing between several models in least-squares regression with heteroscedastic data. We prove that any penalization procedure is suboptimal when the penalty is a function of the dimension of the model, at least for some typical heteroscedastic model selection problems. In particular, Mallows' Cp is suboptimal in this framework. On the contrary, optimal model selection is possible with data-driven penalties such as resampling or $V$-fold penalties. Therefore, it is worth estimating the shape of the penalty from data, even at the price of a higher computational cost. Simulation experiments illustrate the existence of a trade-off between statistical accuracy and computational complexity. As a conclusion, we sketch some rules for choosing a penalty in least-squares regression, depending on what is known about possible variations of the noise-level.

## Representation of the penalty term of dynamic concave utilities

Delbaen, Freddy; Peng, Shige; Gianin, Emanuela Rosazza
Tipo: Artigo de Revista Científica
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In this paper we will provide a representation of the penalty term of general dynamic concave utilities (hence of dynamic convex risk measures) by applying the theory of g-expectations.; Comment: An updated version is published in Finance & Stochastics. The final publication is available at http://www.springerlink.com

## The ADMM penalized decoder for LDPC codes

Liu, Xishuo; Draper, Stark C.
Tipo: Artigo de Revista Científica
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55.51%
Linear programming (LP) decoding for low-density parity-check (LDPC) codes proposed by Feldman et al. is shown to have theoretical guarantees in several regimes and empirically is not observed to suffer from an error floor. However at low signal-to-noise ratios (SNRs), LP decoding is observed to have worse error performance than belief propagation (BP) decoding. In this paper, we seek to improve LP decoding at low SNRs while still achieving good high SNR performance. We first present a new decoding framework obtained by trying to solve a non-convex optimization problem using the alternating direction method of multipliers (ADMM). This non-convex problem is constructed by adding a penalty term to the LP decoding objective. The goal of the penalty term is to make "pseudocodewords", which are the non-integer vertices of the LP relaxation to which the LP decoder fails, more costly. We name this decoder class the "ADMM penalized decoder". In our simulation results, the ADMM penalized decoder with $\ell_1$ and $\ell_2$ penalties outperforms both BP and LP decoding at all SNRs. For high SNR regimes where it is infeasible to simulate, we use an instanton analysis and show that the ADMM penalized decoder has better high SNR performance than BP decoding. We also develop a reweighted LP decoder using linear approximations to the objective with an $\ell_1$ penalty. We show that this decoder has an improved theoretical recovery threshold compared to LP decoding. In addition...

## ADMM LP decoding of non-binary LDPC codes in $\mathbb{F}_{2^m}$

Liu, Xishuo; Draper, Stark C.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.45%
In this paper, we develop efficient decoders for non-binary low-density parity-check (LDPC) codes using the alternating direction method of multipliers (ADMM). We apply ADMM to two decoding problems. The first problem is linear programming (LP) decoding. In order to develop an efficient algorithm, we focus on non-binary codes in fields of characteristic two. This allows us to transform each constraint in $\mathbb{F}_{2^m}$ to a set of constraints in $\mathbb{F}_{2}$ that has a factor graph representation. Applying ADMM to the LP decoding problem results in two types of non-trivial sub-routines. The first type requires us to solve an unconstrained quadratic program. We solve this problem efficiently by leveraging new results obtained from studying the above factor graphs. The second type requires Euclidean projection onto polytopes that are studied in the literature, a projection that can be solved efficiently using off-the-shelf techniques, which scale linearly in the dimension of the vector to project. ADMM LP decoding scales linearly with block length, linearly with check degree, and quadratically with field size. The second problem we consider is a penalized LP decoding problem. This problem is obtained by incorporating a penalty term into the LP decoding objective. The purpose of the penalty term is to make non-integer solutions (pseudocodewords) more expensive and hence to improve decoding performance. The ADMM algorithm for the penalized LP problem requires Euclidean projection onto a polytope formed by embedding the constraints specified by the non-binary single parity-check code...

## Local Asymptotics of P-splines

Xiao, Luo; Li, Yingxing; Apanasovich, Tatiyana V.; Ruppert, David
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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This report studies local asymptotics of P-splines with $p$th degree B-splines and a $m$th order difference penalty. Earlier work with $p$ and $m$ restricted is extended to the general case. Asymptotically, penalized splines are kernel estimators with equivalent kernels depending on $m$, but not on $p$. A central limit theorem provides simple expressions for the asymptotic mean and variance. Provided it is fast enough, the divergence rate of the number of knots does not affect the asymptotic distribution. The optimal convergence rate of the penalty parameter is given.; Comment: 34 pages, 1 figure

## Rates of convergence of the Adaptive LASSO estimators to the Oracle distribution and higher order refinements by the bootstrap

Chatterjee, A.; Lahiri, S. N.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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Zou [J. Amer. Statist. Assoc. 101 (2006) 1418-1429] proposed the Adaptive LASSO (ALASSO) method for simultaneous variable selection and estimation of the regression parameters, and established its oracle property. In this paper, we investigate the rate of convergence of the ALASSO estimator to the oracle distribution when the dimension of the regression parameters may grow to infinity with the sample size. It is shown that the rate critically depends on the choices of the penalty parameter and the initial estimator, among other factors, and that confidence intervals (CIs) based on the oracle limit law often have poor coverage accuracy. As an alternative, we consider the residual bootstrap method for the ALASSO estimators that has been recently shown to be consistent; cf. Chatterjee and Lahiri [J. Amer. Statist. Assoc. 106 (2011a) 608-625]. We show that the bootstrap applied to a suitable studentized version of the ALASSO estimator achieves second-order correctness, even when the dimension of the regression parameters is unbounded. Results from a moderately large simulation study show marked improvement in coverage accuracy for the bootstrap CIs over the oracle based CIs.; Comment: Published in at http://dx.doi.org/10.1214/13-AOS1106 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org)

## On Outage and Error Rate Analysis of the Ordered V-BLAST

Loyka, Sergey; Gagnon, Francois
Tipo: Artigo de Revista Científica
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Outage and error rate performance of the ordered BLAST with more than 2 transmit antennas is evaluated for i.i.d. Rayleigh fading channels. A number of lower and upper bounds on the 1st step outage probability at any SNR are derived, which are further used to obtain accurate approximations to average block and total error rates. For m Tx antennas, the effect of the optimal ordering at the first step is an m-fold SNR gain. As m increases to infinity, the BLER decreases to zero, which is a manifestation of the space-time autocoding effect in the V-BLAST. While the sub-optimal ordering (based on the before-projection SNR) suffers a few dB SNR penalty compared to the optimal one, it has a lower computational complexity and a 3 dB SNR gain compared to the unordered V-BLAST and can be an attractive solution for low-complexity/low-energy systems. Uncoded D-BLAST exhibits the same outage and error rate performance as that of the V-BLAST. An SNR penalty of the linear receiver interfaces compared to the BLAST is also evaluated.; Comment: accepted by IEEE Transactions on Wireless Communications

## Pena e funcionalismo sistêmico: uma análise crítica da prevenção geral positiva; Pena e funcionalismo sistêmico: uma análise crítica da prevenção geral positiva

Cacicedo, Patrick Lemos
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Relevância na Pesquisa
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## The part-time pay penalty

Manning, Alan; Petrongolo, Barbara
Fonte: Centre for Economic Performance, London School of Economics and Political Science Publicador: Centre for Economic Performance, London School of Economics and Political Science
Tipo: Monograph; NonPeerReviewed Formato: application/pdf