ivar Honduran Lempira(HNL)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 9:00:00 UTC 1 Honduran Lempira = 0.399 Venezuelan Bolivar Fuerte Full Article Honduran Lempira
ivar Australian Dollar(AUD)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 9:00:00 UTC 1 Australian Dollar = 6.5261 Venezuelan Bolivar Fuerte Full Article Australian Dollar
ivar Chinese Yuan Renminbi(CNY)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 6:20:46 UTC 1 Chinese Yuan Renminbi = 1.4118 Venezuelan Bolivar Fuerte Full Article Chinese Yuan Renminbi
ivar Hungarian Forint(HUF)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 9:00:00 UTC 1 Hungarian Forint = 0.0309 Venezuelan Bolivar Fuerte Full Article Hungarian Forint
ivar Philippine Peso(PHP)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 9:00:00 UTC 1 Philippine Peso = 0.1978 Venezuelan Bolivar Fuerte Full Article Philippine Peso
ivar Kenyan Shilling(KES)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:59:59 UTC 1 Kenyan Shilling = 0.0942 Venezuelan Bolivar Fuerte Full Article Kenyan Shilling
ivar Latvian Lat(LVL)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:59:59 UTC 1 Latvian Lat = 16.5113 Venezuelan Bolivar Fuerte Full Article Latvian Lat
ivar Egyptian Pound(EGP)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:59:59 UTC 1 Egyptian Pound = 0.6417 Venezuelan Bolivar Fuerte Full Article Egyptian Pound
ivar Botswana Pula(BWP)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:59:59 UTC 1 Botswana Pula = 0.8224 Venezuelan Bolivar Fuerte Full Article Botswana Pula
ivar Bulgarian Lev(BGN)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:59:59 UTC 1 Bulgarian Lev = 5.5317 Venezuelan Bolivar Fuerte Full Article Bulgarian Lev
ivar Canadian Dollar(CAD)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 3:00:03 UTC 1 Canadian Dollar = 7.125 Venezuelan Bolivar Fuerte Full Article Canadian Dollar
ivar Euro(EUR)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 1:23:50 UTC 1 Euro = 10.9568 Venezuelan Bolivar Fuerte Full Article Euro
ivar Mexican Peso(MXN)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 6:22:05 UTC 1 Mexican Peso = 0.4219 Venezuelan Bolivar Fuerte Full Article Mexican Peso
ivar Brazilian Real(BRL)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:59:58 UTC 1 Brazilian Real = 1.7423 Venezuelan Bolivar Fuerte Full Article Brazilian Real
ivar United Arab Emirates Dirham(AED)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:59:58 UTC 1 United Arab Emirates Dirham = 2.7191 Venezuelan Bolivar Fuerte Full Article United Arab Emirates Dirham
ivar Sri Lanka Rupee(LKR)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:16:58 UTC 1 Sri Lanka Rupee = 0.0535 Venezuelan Bolivar Fuerte Full Article Sri Lanka Rupee
ivar Algerian Dinar(DZD)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:59:57 UTC 1 Algerian Dinar = 0.0778 Venezuelan Bolivar Fuerte Full Article Algerian Dinar
ivar Indonesian Rupiah(IDR)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 2:59:06 UTC 1 Indonesian Rupiah = 0.0007 Venezuelan Bolivar Fuerte Full Article Indonesian Rupiah
ivar Lithuanian Lita(LTL)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:59:56 UTC 1 Lithuanian Lita = 3.3825 Venezuelan Bolivar Fuerte Full Article Lithuanian Lita
ivar Nigerian Naira(NGN)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:59:56 UTC 1 Nigerian Naira = 0.0256 Venezuelan Bolivar Fuerte Full Article Nigerian Naira
ivar Czech Republic Koruna(CZK)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:59:55 UTC 1 Czech Republic Koruna = 0.3974 Venezuelan Bolivar Fuerte Full Article Czech Republic Koruna
ivar Bolivian Boliviano(BOB)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 8:59:55 UTC 1 Bolivian Boliviano = 1.4484 Venezuelan Bolivar Fuerte Full Article Bolivian Boliviano
ivar Japanese Yen(JPY)/Venezuelan Bolivar Fuerte(VEF) By www.fx-exchange.com Published On :: Sun May 10 2020 3:42:51 UTC 1 Japanese Yen = 0.0936 Venezuelan Bolivar Fuerte Full Article Japanese Yen
ivar Shivarajkumar To Announce His Next On Dr Rajkumar’s Birthday? To Be Directed By THIS Telugu Talent! By www.filmibeat.com Published On :: Fri, 24 Apr 2020 15:39:54 +0530 Due to COVID-19 Lockdown, the entire world on cinema has come to halt. However, Century star Shivarajkumar is keeping busy with script narrations. The actor, in all likelihood, may officially announce his next project on father and yesteryear megastar Dr. Rajkumar’s Full Article
ivar FilmWeek: ‘I Still Believe,’ ‘Banana Split,’ ‘Vivarium’ and more By feeds.scpr.org Published On :: Fri, 27 Mar 2020 08:57:26 -0700 KJ Apa and Britt Robertson in "I Still Believe" ; Credit: Lionsgate/I Still Believe (2020) FilmWeek®Larry Mantle and KPCC film critics Amy Nicholson and Wade Major review this weekend’s new movie releases. "I Still Believe" on VOD "Banana Split" on VOD "Vivarium" on VOD "Resistance" on VOD "Vitalina Varela" on GrasshopperFilm.com "Uncorked" on Netflix "Dosed" on film's website "The Occupant" on Netflix "Tape" on VOD "There's Something In The Water" on Netflix Guests: Amy Nicholson, film critic for KPCC, film writer for The Guardian and host of the podcasts ‘Unspooled’ and the podcast miniseries “Zoom”; she tweets @TheAmyNicholson Wade Major, film critic for KPCC and CineGods.com This content is from Southern California Public Radio. View the original story at SCPR.org. Full Article
ivar Equivariant Batalin-Vilkovisky formalism. (arXiv:1907.07995v3 [hep-th] UPDATED) By arxiv.org Published On :: We study an equivariant extension of the Batalin-Vilkovisky formalism for quantizing gauge theories. Namely, we introduce a general framework to encompass failures of the quantum master equation, and we apply it to the natural equivariant extension of AKSZ solutions of the classical master equation (CME). As examples of the construction, we recover the equivariant extension of supersymmetric Yang-Mills in 2d and of Donaldson-Witten theory. Full Article
ivar Smooth non-projective equivariant completions of affine spaces. (arXiv:2005.03277v1 [math.AG]) By arxiv.org Published On :: In this paper we construct an equivariant embedding of the affine space $mathbb{A}^n$ with the translation group action into a complete non-projective algebraic variety $X$ for all $n geq 3$. The theory of toric varieties is used as the main tool for this construction. In the case of $n = 3$ we describe the orbit structure on the variety $X$. Full Article
ivar Barley cultivar BG-161 By www.freepatentsonline.com Published On :: Tue, 26 May 2015 08:00:00 EDT A barley cultivar, designated BG-161, is disclosed. The invention relates to seeds, plants, and hybrids of barley cultivar BG-161, and methods for producing a barley plant produced by crossing plants from barley cultivar BG-161 with themselves or plants from another barley variety. The invention also relates to methods for producing a barley plant containing in its genetic material one or more transgenes and to the transgenic barley plants and plant parts produced by those methods. The invention also relates to barley varieties derived from barley cultivar BG-161, to methods for producing other barley varieties, lines or plant parts derived from barley cultivar BG-161, and to the barley plants, varieties, and their parts derived from the use of those methods. The invention further relates to hybrid barley seeds and plants produced by crossing barley cultivar BG-161 with another barley cultivar. Full Article
ivar Soybean cultivar 131TD735 By www.freepatentsonline.com Published On :: Tue, 26 May 2015 08:00:00 EDT A soybean cultivar designated 131TD735 is disclosed. The invention relates to the seeds of soybean cultivar 131TD735, to the plants of soybean 131TD735, to plant parts of soybean cultivar 131TD735 and to methods for producing a soybean plant produced by crossing soybean cultivar 131TD735 with itself or with another soybean variety. The invention also relates to methods for producing a soybean plant containing in its genetic material one or more transgenes and to the transgenic soybean plants and plant parts produced by those methods. This invention also relates to soybean cultivars or breeding cultivars and plant parts derived from soybean cultivar 131TD735, to methods for producing other soybean cultivars, lines or plant parts derived from soybean cultivar 131TD735 and to the soybean plants, varieties, and their parts derived from use of those methods. The invention further relates to hybrid soybean seeds, plants and plant parts produced by crossing the cultivar 131TD735 with another soybean cultivar. Full Article
ivar Craig Naivar joins Clay Helton's staff as USC's new safeties coach By www.latimes.com Published On :: Sat, 1 Feb 2020 13:46:16 -0500 Craig Naivar is named safeties coach at USC, where he will rejoin defensive coordinator Todd Orlando, with whom he worked at Texas and Houston. Full Article
ivar Near Soliton Evolution for Equivariant Schrodinger Maps in Two Spatial Dimensions By www.ams.org Published On :: Ioan Bejenaru, University of California, San Diego, and Daniel Tataru, University of California, Berkeley - AMS, 2014, 108 pp., Softcover, ISBN-13: 978-0-8218-9215-2, List: US$76, All AMS Members: US$60.80, MEMO/228/1069 The authors consider the Schrödinger Map equation in (2+1) dimensions, with values into (mathbb{S}^2). This admits a lowest energy steady... Full Article
ivar A Bivariate Genome-Wide Approach to Metabolic Syndrome: STAMPEED Consortium By diabetes.diabetesjournals.org Published On :: 2011-04-01 Aldi T. KrajaApr 1, 2011; 60:1329-1339Genetics Full Article
ivar Efficacy and Safety of Cannabidiol and Tetrahydrocannabivarin on Glycemic and Lipid Parameters in Patients With Type 2 Diabetes: A Randomized, Double-Blind, Placebo-Controlled, Parallel Group Pilot Study By care.diabetesjournals.org Published On :: 2016-10-01 Khalid A. JadoonOct 1, 2016; 39:1777-1786Emerging Technologies and Therapeutics Full Article
ivar Univariate mean change point detection: Penalization, CUSUM and optimality By projecteuclid.org Published On :: Mon, 27 Apr 2020 22:02 EDT Daren Wang, Yi Yu, Alessandro Rinaldo. Source: Electronic Journal of Statistics, Volume 14, Number 1, 1917--1961.Abstract: The problem of univariate mean change point detection and localization based on a sequence of $n$ independent observations with piecewise constant means has been intensively studied for more than half century, and serves as a blueprint for change point problems in more complex settings. We provide a complete characterization of this classical problem in a general framework in which the upper bound $sigma ^{2}$ on the noise variance, the minimal spacing $Delta $ between two consecutive change points and the minimal magnitude $kappa $ of the changes, are allowed to vary with $n$. We first show that consistent localization of the change points is impossible in the low signal-to-noise ratio regime $frac{kappa sqrt{Delta }}{sigma }preceq sqrt{log (n)}$. In contrast, when $frac{kappa sqrt{Delta }}{sigma }$ diverges with $n$ at the rate of at least $sqrt{log (n)}$, we demonstrate that two computationally-efficient change point estimators, one based on the solution to an $ell _{0}$-penalized least squares problem and the other on the popular wild binary segmentation algorithm, are both consistent and achieve a localization rate of the order $frac{sigma ^{2}}{kappa ^{2}}log (n)$. We further show that such rate is minimax optimal, up to a $log (n)$ term. Full Article
ivar Bias correction in conditional multivariate extremes By projecteuclid.org Published On :: Wed, 22 Apr 2020 04:02 EDT Mikael Escobar-Bach, Yuri Goegebeur, Armelle Guillou. Source: Electronic Journal of Statistics, Volume 14, Number 1, 1773--1795.Abstract: We consider bias-corrected estimation of the stable tail dependence function in the regression context. To this aim, we first estimate the bias of a smoothed estimator of the stable tail dependence function, and then we subtract it from the estimator. The weak convergence, as a stochastic process, of the resulting asymptotically unbiased estimator of the conditional stable tail dependence function, correctly normalized, is established under mild assumptions, the covariate argument being fixed. The finite sample behaviour of our asymptotically unbiased estimator is then illustrated on a simulation study and compared to two alternatives, which are not bias corrected. Finally, our methodology is applied to a dataset of air pollution measurements. Full Article
ivar A fast and consistent variable selection method for high-dimensional multivariate linear regression with a large number of explanatory variables By projecteuclid.org Published On :: Fri, 27 Mar 2020 22:00 EDT Ryoya Oda, Hirokazu Yanagihara. Source: Electronic Journal of Statistics, Volume 14, Number 1, 1386--1412.Abstract: We put forward a variable selection method for selecting explanatory variables in a normality-assumed multivariate linear regression. It is cumbersome to calculate variable selection criteria for all subsets of explanatory variables when the number of explanatory variables is large. Therefore, we propose a fast and consistent variable selection method based on a generalized $C_{p}$ criterion. The consistency of the method is provided by a high-dimensional asymptotic framework such that the sample size and the sum of the dimensions of response vectors and explanatory vectors divided by the sample size tend to infinity and some positive constant which are less than one, respectively. Through numerical simulations, it is shown that the proposed method has a high probability of selecting the true subset of explanatory variables and is fast under a moderate sample size even when the number of dimensions is large. Full Article
ivar Sparse and low-rank multivariate Hawkes processes By Published On :: 2020 We consider the problem of unveiling the implicit network structure of node interactions (such as user interactions in a social network), based only on high-frequency timestamps. Our inference is based on the minimization of the least-squares loss associated with a multivariate Hawkes model, penalized by $ell_1$ and trace norm of the interaction tensor. We provide a first theoretical analysis for this problem, that includes sparsity and low-rank inducing penalizations. This result involves a new data-driven concentration inequality for matrix martingales in continuous time with observable variance, which is a result of independent interest and a broad range of possible applications since it extends to matrix martingales former results restricted to the scalar case. A consequence of our analysis is the construction of sharply tuned $ell_1$ and trace-norm penalizations, that leads to a data-driven scaling of the variability of information available for each users. Numerical experiments illustrate the significant improvements achieved by the use of such data-driven penalizations. Full Article
ivar Multivariate normal approximation of the maximum likelihood estimator via the delta method By projecteuclid.org Published On :: Mon, 03 Feb 2020 04:00 EST Andreas Anastasiou, Robert E. Gaunt. Source: Brazilian Journal of Probability and Statistics, Volume 34, Number 1, 136--149.Abstract: We use the delta method and Stein’s method to derive, under regularity conditions, explicit upper bounds for the distributional distance between the distribution of the maximum likelihood estimator (MLE) of a $d$-dimensional parameter and its asymptotic multivariate normal distribution. Our bounds apply in situations in which the MLE can be written as a function of a sum of i.i.d. $t$-dimensional random vectors. We apply our general bound to establish a bound for the multivariate normal approximation of the MLE of the normal distribution with unknown mean and variance. Full Article
ivar Option pricing with bivariate risk-neutral density via copula and heteroscedastic model: A Bayesian approach By projecteuclid.org Published On :: Mon, 26 Aug 2019 04:00 EDT Lucas Pereira Lopes, Vicente Garibay Cancho, Francisco Louzada. Source: Brazilian Journal of Probability and Statistics, Volume 33, Number 4, 801--825.Abstract: Multivariate options are adequate tools for multi-asset risk management. The pricing models derived from the pioneer Black and Scholes method under the multivariate case consider that the asset-object prices follow a Brownian geometric motion. However, the construction of such methods imposes some unrealistic constraints on the process of fair option calculation, such as constant volatility over the maturity time and linear correlation between the assets. Therefore, this paper aims to price and analyze the fair price behavior of the call-on-max (bivariate) option considering marginal heteroscedastic models with dependence structure modeled via copulas. Concerning inference, we adopt a Bayesian perspective and computationally intensive methods based on Monte Carlo simulations via Markov Chain (MCMC). A simulation study examines the bias, and the root mean squared errors of the posterior means for the parameters. Real stocks prices of Brazilian banks illustrate the approach. For the proposed method is verified the effects of strike and dependence structure on the fair price of the option. The results show that the prices obtained by our heteroscedastic model approach and copulas differ substantially from the prices obtained by the model derived from Black and Scholes. Empirical results are presented to argue the advantages of our strategy. Full Article
ivar Flexible, boundary adapted, nonparametric methods for the estimation of univariate piecewise-smooth functions By projecteuclid.org Published On :: Tue, 04 Feb 2020 04:00 EST Umberto Amato, Anestis Antoniadis, Italia De Feis. Source: Statistics Surveys, Volume 14, 32--70.Abstract: We present and compare some nonparametric estimation methods (wavelet and/or spline-based) designed to recover a one-dimensional piecewise-smooth regression function in both a fixed equidistant or not equidistant design regression model and a random design model. Wavelet methods are known to be very competitive in terms of denoising and compression, due to the simultaneous localization property of a function in time and frequency. However, boundary assumptions, such as periodicity or symmetry, generate bias and artificial wiggles which degrade overall accuracy. Simple methods have been proposed in the literature for reducing the bias at the boundaries. We introduce new ones based on adaptive combinations of two estimators. The underlying idea is to combine a highly accurate method for non-regular functions, e.g., wavelets, with one well behaved at boundaries, e.g., Splines or Local Polynomial. We provide some asymptotic optimal results supporting our approach. All the methods can handle data with a random design. We also sketch some generalization to the multidimensional setting. To study the performance of the proposed approaches we have conducted an extensive set of simulations on synthetic data. An interesting regression analysis of two real data applications using these procedures unambiguously demonstrates their effectiveness. Full Article
ivar Measuring multivariate association and beyond By projecteuclid.org Published On :: Wed, 16 Nov 2016 22:00 EST Julie Josse, Susan Holmes. Source: Statistics Surveys, Volume 10, 132--167.Abstract: Simple correlation coefficients between two variables have been generalized to measure association between two matrices in many ways. Coefficients such as the RV coefficient, the distance covariance (dCov) coefficient and kernel based coefficients are being used by different research communities. Scientists use these coefficients to test whether two random vectors are linked. Once it has been ascertained that there is such association through testing, then a next step, often ignored, is to explore and uncover the association’s underlying patterns. This article provides a survey of various measures of dependence between random vectors and tests of independence and emphasizes the connections and differences between the various approaches. After providing definitions of the coefficients and associated tests, we present the recent improvements that enhance their statistical properties and ease of interpretation. We summarize multi-table approaches and provide scenarii where the indices can provide useful summaries of heterogeneous multi-block data. We illustrate these different strategies on several examples of real data and suggest directions for future research. Full Article
ivar $M$-functionals of multivariate scatter By projecteuclid.org Published On :: Fri, 20 Mar 2015 09:11 EDT Lutz Dümbgen, Markus Pauly, Thomas Schweizer. Source: Statistics Surveys, Volume 9, 32--105.Abstract: This survey provides a self-contained account of $M$-estimation of multivariate scatter. In particular, we present new proofs for existence of the underlying $M$-functionals and discuss their weak continuity and differentiability. This is done in a rather general framework with matrix-valued random variables. By doing so we reveal a connection between Tyler’s (1987a) $M$-functional of scatter and the estimation of proportional covariance matrices. Moreover, this general framework allows us to treat a new class of scatter estimators, based on symmetrizations of arbitrary order. Finally these results are applied to $M$-estimation of multivariate location and scatter via multivariate $t$-distributions. Full Article
ivar Semi-parametric estimation for conditional independence multivariate finite mixture models By projecteuclid.org Published On :: Fri, 06 Feb 2015 08:39 EST Didier Chauveau, David R. Hunter, Michael Levine. Source: Statistics Surveys, Volume 9, 1--31.Abstract: The conditional independence assumption for nonparametric multivariate finite mixture models, a weaker form of the well-known conditional independence assumption for random effects models for longitudinal data, is the subject of an increasing number of theoretical and algorithmic developments in the statistical literature. After presenting a survey of this literature, including an in-depth discussion of the all-important identifiability results, this article describes and extends an algorithm for estimation of the parameters in these models. The algorithm works for any number of components in three or more dimensions. It possesses a descent property and can be easily adapted to situations where the data are grouped in blocks of conditionally independent variables. We discuss how to adapt this algorithm to various location-scale models that link component densities, and we even adapt it to a particular class of univariate mixture problems in which the components are assumed symmetric. We give a bandwidth selection procedure for our algorithm. Finally, we demonstrate the effectiveness of our algorithm using a simulation study and two psychometric datasets. Full Article
ivar Bayesian factor models for multivariate categorical data obtained from questionnaires. (arXiv:1910.04283v2 [stat.AP] UPDATED) By arxiv.org Published On :: Factor analysis is a flexible technique for assessment of multivariate dependence and codependence. Besides being an exploratory tool used to reduce the dimensionality of multivariate data, it allows estimation of common factors that often have an interesting theoretical interpretation in real problems. However, standard factor analysis is only applicable when the variables are scaled, which is often inappropriate, for example, in data obtained from questionnaires in the field of psychology,where the variables are often categorical. In this framework, we propose a factor model for the analysis of multivariate ordered and non-ordered polychotomous data. The inference procedure is done under the Bayesian approach via Markov chain Monte Carlo methods. Two Monte-Carlo simulation studies are presented to investigate the performance of this approach in terms of estimation bias, precision and assessment of the number of factors. We also illustrate the proposed method to analyze participants' responses to the Motivational State Questionnaire dataset, developed to study emotions in laboratory and field settings. Full Article
ivar Local Cascade Ensemble for Multivariate Data Classification. (arXiv:2005.03645v1 [cs.LG]) By arxiv.org Published On :: We present LCE, a Local Cascade Ensemble for traditional (tabular) multivariate data classification, and its extension LCEM for Multivariate Time Series (MTS) classification. LCE is a new hybrid ensemble method that combines an explicit boosting-bagging approach to handle the usual bias-variance tradeoff faced by machine learning models and an implicit divide-and-conquer approach to individualize classifier errors on different parts of the training data. Our evaluation firstly shows that the hybrid ensemble method LCE outperforms the state-of-the-art classifiers on the UCI datasets and that LCEM outperforms the state-of-the-art MTS classifiers on the UEA datasets. Furthermore, LCEM provides explainability by design and manifests robust performance when faced with challenges arising from continuous data collection (different MTS length, missing data and noise). Full Article
ivar Fast multivariate empirical cumulative distribution function with connection to kernel density estimation. (arXiv:2005.03246v1 [cs.DS]) By arxiv.org Published On :: This paper revisits the problem of computing empirical cumulative distribution functions (ECDF) efficiently on large, multivariate datasets. Computing an ECDF at one evaluation point requires $mathcal{O}(N)$ operations on a dataset composed of $N$ data points. Therefore, a direct evaluation of ECDFs at $N$ evaluation points requires a quadratic $mathcal{O}(N^2)$ operations, which is prohibitive for large-scale problems. Two fast and exact methods are proposed and compared. The first one is based on fast summation in lexicographical order, with a $mathcal{O}(N{log}N)$ complexity and requires the evaluation points to lie on a regular grid. The second one is based on the divide-and-conquer principle, with a $mathcal{O}(Nlog(N)^{(d-1){vee}1})$ complexity and requires the evaluation points to coincide with the input points. The two fast algorithms are described and detailed in the general $d$-dimensional case, and numerical experiments validate their speed and accuracy. Secondly, the paper establishes a direct connection between cumulative distribution functions and kernel density estimation (KDE) for a large class of kernels. This connection paves the way for fast exact algorithms for multivariate kernel density estimation and kernel regression. Numerical tests with the Laplacian kernel validate the speed and accuracy of the proposed algorithms. A broad range of large-scale multivariate density estimation, cumulative distribution estimation, survival function estimation and regression problems can benefit from the proposed numerical methods. Full Article
ivar mvord: An R Package for Fitting Multivariate Ordinal Regression Models By www.jstatsoft.org Published On :: Sat, 18 Apr 2020 03:35:08 +0000 The R package mvord implements composite likelihood estimation in the class of multivariate ordinal regression models with a multivariate probit and a multivariate logit link. A flexible modeling framework for multiple ordinal measurements on the same subject is set up, which takes into consideration the dependence among the multiple observations by employing different error structures. Heterogeneity in the error structure across the subjects can be accounted for by the package, which allows for covariate dependent error structures. In addition, different regression coefficients and threshold parameters for each response are supported. If a reduction of the parameter space is desired, constraints on the threshold as well as on the regression coefficients can be specified by the user. The proposed multivariate framework is illustrated by means of a credit risk application. Full Article
ivar Adaptive risk bounds in univariate total variation denoising and trend filtering By projecteuclid.org Published On :: Mon, 17 Feb 2020 04:02 EST Adityanand Guntuboyina, Donovan Lieu, Sabyasachi Chatterjee, Bodhisattva Sen. Source: The Annals of Statistics, Volume 48, Number 1, 205--229.Abstract: We study trend filtering, a relatively recent method for univariate nonparametric regression. For a given integer $rgeq1$, the $r$th order trend filtering estimator is defined as the minimizer of the sum of squared errors when we constrain (or penalize) the sum of the absolute $r$th order discrete derivatives of the fitted function at the design points. For $r=1$, the estimator reduces to total variation regularization which has received much attention in the statistics and image processing literature. In this paper, we study the performance of the trend filtering estimator for every $rgeq1$, both in the constrained and penalized forms. Our main results show that in the strong sparsity setting when the underlying function is a (discrete) spline with few “knots,” the risk (under the global squared error loss) of the trend filtering estimator (with an appropriate choice of the tuning parameter) achieves the parametric $n^{-1}$-rate, up to a logarithmic (multiplicative) factor. Our results therefore provide support for the use of trend filtering, for every $rgeq1$, in the strong sparsity setting. Full Article
ivar Adaptive estimation of the rank of the coefficient matrix in high-dimensional multivariate response regression models By projecteuclid.org Published On :: Wed, 30 Oct 2019 22:03 EDT Xin Bing, Marten H. Wegkamp. Source: The Annals of Statistics, Volume 47, Number 6, 3157--3184.Abstract: We consider the multivariate response regression problem with a regression coefficient matrix of low, unknown rank. In this setting, we analyze a new criterion for selecting the optimal reduced rank. This criterion differs notably from the one proposed in Bunea, She and Wegkamp ( Ann. Statist. 39 (2011) 1282–1309) in that it does not require estimation of the unknown variance of the noise, nor does it depend on a delicate choice of a tuning parameter. We develop an iterative, fully data-driven procedure, that adapts to the optimal signal-to-noise ratio. This procedure finds the true rank in a few steps with overwhelming probability. At each step, our estimate increases, while at the same time it does not exceed the true rank. Our finite sample results hold for any sample size and any dimension, even when the number of responses and of covariates grow much faster than the number of observations. We perform an extensive simulation study that confirms our theoretical findings. The new method performs better and is more stable than the procedure of Bunea, She and Wegkamp ( Ann. Statist. 39 (2011) 1282–1309) in both low- and high-dimensional settings. Full Article
ivar Distance multivariance: New dependence measures for random vectors By projecteuclid.org Published On :: Fri, 02 Aug 2019 22:04 EDT Björn Böttcher, Martin Keller-Ressel, René L. Schilling. Source: The Annals of Statistics, Volume 47, Number 5, 2757--2789.Abstract: We introduce two new measures for the dependence of $nge2$ random variables: distance multivariance and total distance multivariance . Both measures are based on the weighted $L^{2}$-distance of quantities related to the characteristic functions of the underlying random variables. These extend distance covariance (introduced by Székely, Rizzo and Bakirov) from pairs of random variables to $n$-tuplets of random variables. We show that total distance multivariance can be used to detect the independence of $n$ random variables and has a simple finite-sample representation in terms of distance matrices of the sample points, where distance is measured by a continuous negative definite function. Under some mild moment conditions, this leads to a test for independence of multiple random vectors which is consistent against all alternatives. Full Article