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  2. Newey–West estimator - Wikipedia

    en.wikipedia.org/wiki/Newey–West_estimator

    A Newey–West estimator is used in statistics and econometrics to provide an estimate of the covariance matrix of the parameters of a regression-type model where the standard assumptions of regression analysis do not apply. [1] It was devised by Whitney K. Newey and Kenneth D. West in 1987, although there are a number of later variants.

  3. Domain adaptation - Wikipedia

    en.wikipedia.org/wiki/Domain_Adaptation

    Prior Shift (Label Shift) occurs when the label distribution differs between the source and target datasets, while the conditional distribution of features given labels remains the same. An example is a classifier of hair color in images from Italy (source domain) and Norway (target domain).

  4. Covariance function - Wikipedia

    en.wikipedia.org/wiki/Covariance_function

    In probability theory and statistics, the covariance function describes how much two random variables change together (their covariance) with varying spatial or temporal separation. For a random field or stochastic process Z ( x ) on a domain D , a covariance function C ( x , y ) gives the covariance of the values of the random field at the two ...

  5. Covariance and contravariance (computer science) - Wikipedia

    en.wikipedia.org/wiki/Covariance_and_contra...

    An example is the compareTo method: a. compareTo (b) checks whether a comes before or after b in some ordering, but the way to compare, say, two rational numbers will be different from the way to compare two strings. Other common examples of binary methods include equality tests, arithmetic operations, and set operations like subset and union.

  6. Ensemble Kalman filter - Wikipedia

    en.wikipedia.org/wiki/Ensemble_Kalman_filter

    The ensemble Kalman filter (EnKF) is a Monte Carlo implementation of the Bayesian update problem: given a probability density function (PDF) of the state of the modeled system (the prior, called often the forecast in geosciences) and the data likelihood, Bayes' theorem is used to obtain the PDF after the data likelihood has been taken into account (the posterior, often called the analysis).

  7. Whitening transformation - Wikipedia

    en.wikipedia.org/wiki/Whitening_transformation

    A whitening transformation or sphering transformation is a linear transformation that transforms a vector of random variables with a known covariance matrix into a set of new variables whose covariance is the identity matrix, meaning that they are uncorrelated and each have variance 1. [1]

  8. Batch normalization - Wikipedia

    en.wikipedia.org/wiki/Batch_normalization

    The effect of these sources of randomness on the distribution of the inputs to internal layers during training is described as internal covariate shift. Although a clear-cut precise definition seems to be missing, the phenomenon observed in experiments is the change on means and variances of the inputs to internal layers during training.

  9. Hankel matrix - Wikipedia

    en.wikipedia.org/wiki/Hankel_matrix

    The Hankel matrix transform, or simply Hankel transform, of a sequence is the sequence of the determinants of the Hankel matrices formed from .Given an integer >, define the corresponding ()-dimensional Hankel matrix as having the matrix elements [], = +.