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We present new initialization methods for the expectation-maximization algorithm for multivariate Gaussian mixture models. Our methods are adaptions of the well-known $K$-means++ initialization and the Gonzalez algorithm. Thereby we aim to…

Machine Learning · Computer Science 2017-05-31 Johannes Blömer , Kathrin Bujna

Over half a century old and showing no signs of aging, k-means remains one of the most popular data processing algorithms. As is well-known, a proper initialization of k-means is crucial for obtaining a good final solution. The recently…

Databases · Computer Science 2012-03-30 Bahman Bahmani , Benjamin Moseley , Andrea Vattani , Ravi Kumar , Sergei Vassilvitskii

Adaptive importance sampling is a powerful tool to sample from complicated target densities, but its success depends sensitively on the initial proposal density. An algorithm is presented to automatically perform the initialization using…

Computation · Statistics 2013-05-01 Frederik Beaujean , Allen Caldwell

With origins in game theory, probabilistic values like Shapley values, Banzhaf values, and semi-values have emerged as a central tool in explainable AI. They are used for feature attribution, data attribution, data valuation, and more.…

Machine Learning · Computer Science 2026-01-14 R. Teal Witter , Yurong Liu , Christopher Musco

We introduce a novel exploratory technique, termed biarchetype analysis, which extends archetype analysis to simultaneously identify archetypes of both observations and features. This innovative unsupervised machine learning tool aims to…

Methodology · Statistics 2024-05-24 Aleix Alcacer , Irene Epifanio , Ximo Gual-Arnau

This article briefly introduced Arthur and Vassilvitshii's work on \textbf{k-means++} algorithm and further generalized the center initialization process. It is found that choosing the most distant sample point from the nearest center as…

Machine Learning · Computer Science 2019-03-26 Yiwei Li

Archetypal analysis is an exploratory tool that explains a set of observations as mixtures of pure (extreme) patterns. If the patterns are actual observations of the sample, we refer to them as archetypoids. For the first time, we propose…

Applications · Statistics 2020-06-30 Ismael Cabero , Irene Epifanio

K-means is undoubtedly the most widely used partitional clustering algorithm. Unfortunately, due to its gradient descent nature, this algorithm is highly sensitive to the initial placement of the cluster centers. Numerous initialization…

Machine Learning · Computer Science 2013-04-30 M. Emre Celebi , Hassan A. Kingravi

K-means is undoubtedly the most widely used partitional clustering algorithm. Unfortunately, due to its gradient descent nature, this algorithm is highly sensitive to the initial placement of the cluster centers. Numerous initialization…

Machine Learning · Computer Science 2012-09-11 M. Emre Celebi , Hassan A. Kingravi , Patricio A. Vela

We introduce AlphaRank, an artificial intelligence approach to address the fixed-budget ranking and selection (R&S) problems. We formulate the sequential sampling decision as a Markov decision process and propose a Monte Carlo…

Machine Learning · Computer Science 2024-02-05 Ruihan Zhou , L. Jeff Hong , Yijie Peng

We consider the problem of estimating the factors of a rank-$1$ matrix with i.i.d. Gaussian, rank-$1$ measurements that are nonlinearly transformed and corrupted by noise. Considering two prototypical choices for the nonlinearity, we study…

Optimization and Control · Mathematics 2024-10-02 Kabir Aladin Chandrasekher , Mengqi Lou , Ashwin Pananjady

Archetypal analysis represents each individual member of a set of data vectors as a mixture (a constrained linear combination) of the pure types or archetypes of the data set. The archetypes are themselves required to be mixtures of the…

Astrophysics · Physics 2009-11-07 B. H. P. Chan , D. A. Mitchell , L. E. Cram

It is well known that good initializations can improve the speed and accuracy of the solutions of many nonnegative matrix factorization (NMF) algorithms. Many NMF algorithms are sensitive with respect to the initialization of W or H or…

Numerical Analysis · Computer Science 2014-07-29 Amy N. Langville , Carl D. Meyer , Russell Albright , James Cox , David Duling

Stochastic variational inference is an established way to carry out approximate Bayesian inference for deep models. While there have been effective proposals for good initializations for loss minimization in deep learning, far less…

Machine Learning · Statistics 2019-01-28 Simone Rossi , Pietro Michiardi , Maurizio Filippone

We present adaptive sequential SAA (sample average approximation) algorithms to solve large-scale two-stage stochastic linear programs. The iterative algorithm framework we propose is organized into \emph{outer} and \emph{inner} iterations…

Optimization and Control · Mathematics 2020-12-08 Raghu Pasupathy , Yongjia Song

In this work, two new initialization methods for K-means clustering are proposed. Both proposals are based on applying a divide-and-conquer approach for the K-means|| type of an initialization strategy. The second proposal also utilizes…

Machine Learning · Computer Science 2020-07-24 Joonas Hämäläinen , Tommi Kärkkäinen , Tuomo Rossi

Given a collection of data points, non-negative matrix factorization (NMF) suggests to express them as convex combinations of a small set of `archetypes' with non-negative entries. This decomposition is unique only if the true archetypes…

Machine Learning · Statistics 2017-05-09 Hamid Javadi , Andrea Montanari

Autoregressive moving average (ARMA) models are widely used for analyzing time series data. However, standard likelihood-based inference methodology for ARMA models has avoidable limitations. We show that currently accepted standards for…

Methodology · Statistics 2025-10-28 Jesse Wheeler , Edward L. Ionides

We propose AAA rational approximation as a method for interpolating or approximating smooth functions from equispaced data samples. Although it is always better to approximate from large numbers of samples if they are available, whether…

Numerical Analysis · Mathematics 2022-07-26 Daan Huybrechs , Lloyd N. Trefethen

This paper introduces a novel framework for Archetypal Analysis (AA) tailored to ordinal data, particularly from questionnaires. Unlike existing methods, the proposed method, Ordinal Archetypal Analysis (OAA), bypasses the two-step process…