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A Modified Energy Statistic for Unsupervised Anomaly Detection
A Modified Energy Statistic for Unsupervised Anomaly Detection Rupam Mukherjee GE Research, Bangalore, Karnataka, 560066, India [email protected], [email protected] ABSTRACT value. Anomaly is flagged when the distance metric exceeds a threshold and an alert is generated, thereby preventing sud- For prognostics in industrial applications, the degree of an- den unplanned failures. Although as is captured in (Goldstein omaly of a test point from a baseline cluster is estimated using & Uchida, 2016), anomaly may be both supervised and un- a statistical distance metric. Among different statistical dis- supervised in nature depending on the availability of labelled tance metrics, energy distance is an interesting concept based ground-truth data, in this paper anomaly detection is consid- on Newton’s Law of Gravitation, promising simpler comput- ered to be the unsupervised version which is more convenient ation than classical distance metrics. In this paper, we re- and more practical in many industrial systems. view the state of the art formulations of energy distance and point out several reasons why they are not directly applica- Choice of the statistical distance formulation has an important ble to the anomaly-detection problem. Thereby, we propose impact on the effectiveness of RUL estimation. In literature, a new energy-based metric called the -statistic which ad- statistical distances are described to be of two types as fol- P dresses these issues, is applicable to anomaly detection and lows. retains the computational simplicity of the energy distance. We also demonstrate its effectiveness on a real-life data-set. 1. Divergence measures: These estimate the distance (or, similarity) between probability distributions. -
Package 'Energy'
Package ‘energy’ May 27, 2018 Title E-Statistics: Multivariate Inference via the Energy of Data Version 1.7-4 Date 2018-05-27 Author Maria L. Rizzo and Gabor J. Szekely Description E-statistics (energy) tests and statistics for multivariate and univariate inference, including distance correlation, one-sample, two-sample, and multi-sample tests for comparing multivariate distributions, are implemented. Measuring and testing multivariate independence based on distance correlation, partial distance correlation, multivariate goodness-of-fit tests, clustering based on energy distance, testing for multivariate normality, distance components (disco) for non-parametric analysis of structured data, and other energy statistics/methods are implemented. Maintainer Maria Rizzo <[email protected]> Imports Rcpp (>= 0.12.6), stats, boot LinkingTo Rcpp Suggests MASS URL https://github.com/mariarizzo/energy License GPL (>= 2) NeedsCompilation yes Repository CRAN Date/Publication 2018-05-27 21:03:00 UTC R topics documented: energy-package . .2 centering distance matrices . .3 dcor.ttest . .4 dcov.test . .6 dcovU_stats . .8 disco . .9 distance correlation . 12 edist . 14 1 2 energy-package energy.hclust . 16 eqdist.etest . 19 indep.etest . 21 indep.test . 23 mvI.test . 25 mvnorm.etest . 27 pdcor . 28 poisson.mtest . 30 Unbiased distance covariance . 31 U_product . 32 Index 34 energy-package E-statistics: Multivariate Inference via the Energy of Data Description Description: E-statistics (energy) tests and statistics for multivariate and univariate inference, in- cluding distance correlation, one-sample, two-sample, and multi-sample tests for comparing mul- tivariate distributions, are implemented. Measuring and testing multivariate independence based on distance correlation, partial distance correlation, multivariate goodness-of-fit tests, clustering based on energy distance, testing for multivariate normality, distance components (disco) for non- parametric analysis of structured data, and other energy statistics/methods are implemented. -
Testing the Causal Direction of Mediation Effects in Randomized Intervention Studies
Prevention Science (2019) 20:419–430 https://doi.org/10.1007/s11121-018-0900-y Testing the Causal Direction of Mediation Effects in Randomized Intervention Studies Wolfgang Wiedermann1 & Xintong Li1 & Alexander von Eye2 Published online: 21 May 2018 # Society for Prevention Research 2018 Abstract In a recent update of the standards for evidence in research on prevention interventions, the Society of Prevention Research emphasizes the importance of evaluating and testing the causal mechanism through which an intervention is expected to have an effect on an outcome. Mediation analysis is commonly applied to study such causal processes. However, these analytic tools are limited in their potential to fully understand the role of theorized mediators. For example, in a design where the treatment x is randomized and the mediator (m) and the outcome (y) are measured cross-sectionally, the causal direction of the hypothesized mediator-outcome relation is not uniquely identified. That is, both mediation models, x → m → y or x → y → m, may be plausible candidates to describe the underlying intervention theory. As a third explanation, unobserved confounders can still be responsible for the mediator-outcome association. The present study introduces principles of direction dependence which can be used to empirically evaluate these competing explanatory theories. We show that, under certain conditions, third higher moments of variables (i.e., skewness and co-skewness) can be used to uniquely identify the direction of a mediator-outcome relation. Significance procedures compatible with direction dependence are introduced and results of a simulation study are reported that demonstrate the performance of the tests. An empirical example is given for illustrative purposes and a software implementation of the proposed method is provided in SPSS. -
Independence Measures
INDEPENDENCE MEASURES Beatriz Bueno Larraz M´asteren Investigaci´one Innovaci´onen Tecnolog´ıasde la Informaci´ony las Comunicaciones. Escuela Polit´ecnica Superior. M´asteren Matem´aticasy Aplicaciones. Facultad de Ciencias. UNIVERSIDAD AUTONOMA´ DE MADRID 09/03/2015 Advisors: Alberto Su´arezGonz´alez Jo´seRam´onBerrendero D´ıaz ii Acknowledgements This work would not have been possible without the knowledge acquired during both Master degrees. Their subjects have provided me essential notions to carry out this study. The fulfilment of this Master's thesis is the result of the guidances, suggestions and encour- agement of professors D. Jos´eRam´onBerrendero D´ıazand D. Alberto Su´arezGonzalez. They have guided me throughout these months with an open and generous spirit. They have showed an excellent willingness facing the doubts that arose me, and have provided valuable observa- tions for this research. I would like to thank them very much for the opportunity of collaborate with them in this project and for initiating me into research. I would also like to express my gratitude to the postgraduate studies committees of both faculties, specially to the Master's degrees' coordinators. All of them have concerned about my situation due to the change of the normative, and have answered all the questions that I have had. I shall not want to forget, of course, of my family and friends, who have supported and encouraged me during all this time. iii iv Contents 1 Introduction 1 2 Reproducing Kernel Hilbert Spaces (RKHS)3 2.1 Definitions and principal properties..........................3 2.2 Characterizing reproducing kernels..........................6 3 Maximum Mean Discrepancy (MMD) 11 3.1 Definition of MMD.................................. -
Local White Matter Architecture Defines Functional Brain Dynamics
2018 IEEE International Conference on Systems, Man, and Cybernetics Local White Matter Architecture Defines Functional Brain Dynamics Yo Joong Choe* Sivaraman Balakrishnan Aarti Singh Kakao Dept. of Statistics and Data Science Machine Learning Dept. Seongnam-si, South Korea Carnegie Mellon University Carnegie Mellon University [email protected] Pittsburgh, PA, USA Pittsburgh, PA, USA [email protected] [email protected] Jean M. Vettel Timothy Verstynen U.S. Army Research Laboratory Dept. of Psychology and CNBC Aberdeen Proving Ground, MD, USA Carnegie Mellon University [email protected] Pittsburgh, PA, USA [email protected] Abstract—Large bundles of myelinated axons, called white the integrity of the myelin sheath is critical for synchroniz- matter, anatomically connect disparate brain regions together ing information transmission between distal brain areas [2], and compose the structural core of the human connectome. We fostering the ability of these networks to adapt over time recently proposed a method of measuring the local integrity along the length of each white matter fascicle, termed the local [4]. Thus, variability in the myelin sheath, as well as other connectome [1]. If communication efficiency is fundamentally cellular support mechanisms, would contribute to variability constrained by the integrity along the entire length of a white in functional coherence across the circuit. matter bundle [2], then variability in the functional dynamics To study the integrity of structural connectivity, we recently of brain networks should be associated with variability in the introduced the concept of the local connectome. This is local connectome. We test this prediction using two statistical ap- proaches that are capable of handling the high dimensionality of defined as the pattern of fiber systems (i.e., number of fibers, data. -
The Energy Goodness-Of-Fit Test and E-M Type Estimator for Asymmetric Laplace Distributions
THE ENERGY GOODNESS-OF-FIT TEST AND E-M TYPE ESTIMATOR FOR ASYMMETRIC LAPLACE DISTRIBUTIONS John Haman A Dissertation Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY August 2018 Committee: Maria Rizzo, Advisor Joseph Chao, Graduate Faculty Representative Wei Ning Craig Zirbel Copyright c 2018 John Haman All rights reserved iii ABSTRACT Maria Rizzo, Advisor Recently the asymmetric Laplace distribution and its extensions have gained attention in the statistical literature. This may be due to its relatively simple form and its ability to model skew- ness and outliers. For these reasons, the asymmetric Laplace distribution is a reasonable candidate model for certain data that arise in finance, biology, engineering, and other disciplines. For a prac- titioner that wishes to use this distribution, it is very important to check the validity of the model before making inferences that depend on the model. These types of questions are traditionally addressed by goodness-of-fit tests in the statistical literature. In this dissertation, a new goodness-of-fit test is proposed based on energy statistics, a widely applicable class of statistics for which one application is goodness-of-fit testing. The energy goodness-of-fit test has a number of desirable properties. It is consistent against general alter- natives. If the null hypothesis is true, the distribution of the test statistic converges in distribution to an infinite, weighted sum of Chi-square random variables. In addition, we find through simula- tion that the energy test is among the most powerful tests for the asymmetric Laplace distribution in the scenarios considered. -
From Distance Correlation to Multiscale Graph Correlation Arxiv
From Distance Correlation to Multiscale Graph Correlation Cencheng Shen∗1, Carey E. Priebey2, and Joshua T. Vogelsteinz3 1Department of Applied Economics and Statistics, University of Delaware 2Department of Applied Mathematics and Statistics, Johns Hopkins University 3Department of Biomedical Engineering and Institute of Computational Medicine, Johns Hopkins University October 2, 2018 Abstract Understanding and developing a correlation measure that can detect general de- pendencies is not only imperative to statistics and machine learning, but also crucial to general scientific discovery in the big data age. In this paper, we establish a new framework that generalizes distance correlation — a correlation measure that was recently proposed and shown to be universally consistent for dependence testing against all joint distributions of finite moments — to the Multiscale Graph Correla- tion (MGC). By utilizing the characteristic functions and incorporating the nearest neighbor machinery, we formalize the population version of local distance correla- tions, define the optimal scale in a given dependency, and name the optimal local correlation as MGC. The new theoretical framework motivates a theoretically sound ∗[email protected] arXiv:1710.09768v3 [stat.ML] 30 Sep 2018 [email protected] [email protected] 1 Sample MGC and allows a number of desirable properties to be proved, includ- ing the universal consistency, convergence and almost unbiasedness of the sample version. The advantages of MGC are illustrated via a comprehensive set of simula- tions with linear, nonlinear, univariate, multivariate, and noisy dependencies, where it loses almost no power in monotone dependencies while achieving better perfor- mance in general dependencies, compared to distance correlation and other popular methods. -
A Comparative Study of Statistical Methods Used to Identify
Briefings in Bioinformatics Advance Access published August 20, 2013 BRIEFINGS IN BIOINFORMATICS. page1of13 doi:10.1093/bib/bbt051 A comparative study of statistical methods used to identify dependencies between gene expression signals Suzana de Siqueira Santos, Daniel YasumasaTakahashi, Asuka Nakata and Andre¤Fujita Submitted: 18th April 2013; Received (in revised form): 10th June 2013 Abstract One major task in molecular biology is to understand the dependency among genes to model gene regulatory net- works. Pearson’s correlation is the most common method used to measure dependence between gene expression signals, but it works well only when data are linearly associated. For other types of association, such as non-linear Downloaded from or non-functional relationships, methods based on the concepts of rank correlation and information theory-based measures are more adequate than the Pearson’s correlation, but are less used in applications, most probably because of a lack of clear guidelines for their use. This work seeks to summarize the main methods (Pearson’s, Spearman’s and Kendall’s correlations; distance correlation; Hoeffding’s D measure; Heller^Heller^Gorfine measure; mutual in- http://bib.oxfordjournals.org/ formation and maximal information coefficient) used to identify dependency between random variables, especially gene expression data, and also to evaluate the strengths and limitations of each method. Systematic Monte Carlo simulation analyses ranging from sample size, local dependence and linear/non-linear and also non-functional relationships are shown. Moreover, comparisons in actual gene expression data are carried out. Finally, we provide a suggestive list of methods that can be used for each type of data set. -
From Distance Correlation to Multiscale Graph Correlation
From Distance Correlation to Multiscale Graph Correlation Cencheng Shen∗1, Carey E. Priebey2, and Joshua T. Vogelsteinz3 1Department of Applied Economics and Statistics, University of Delaware 2Department of Applied Mathematics and Statistics, Johns Hopkins University 3Department of Biomedical Engineering and Institute of Computational Medicine, Johns Hopkins University January 19, 2019 Abstract Understanding and developing a correlation measure that can detect general de- pendencies is not only imperative to statistics and machine learning, but also crucial to general scientific discovery in the big data age. In this paper, we establish a new framework that generalizes distance correlation — a correlation measure that was recently proposed and shown to be universally consistent for dependence testing against all joint distributions of finite moments — to the Multiscale Graph Correla- tion (MGC). By utilizing the characteristic functions and incorporating the nearest neighbor machinery, we formalize the population version of local distance correla- tions, define the optimal scale in a given dependency, and name the optimal local correlation as MGC. The new theoretical framework motivates a theoretically sound ∗[email protected] [email protected] [email protected] 1 Sample MGC and allows a number of desirable properties to be proved, includ- ing the universal consistency, convergence and almost unbiasedness of the sample version. The advantages of MGC are illustrated via a comprehensive set of simula- tions with linear, nonlinear, univariate, multivariate, and noisy dependencies, where it loses almost no power in monotone dependencies while achieving better perfor- mance in general dependencies, compared to distance correlation and other popular methods. Keywords: testing independence, generalized distance correlation, nearest neighbor graph 2 1 Introduction p q Given pairs of observations (xi; yi) 2 R ×R for i = 1; : : : ; n, assume they are generated by independently identically distributed (iid) FXY . -
University of Aberdeen the Distance Standard Deviation Edelmann, Dominic; Richards, Donald ; Vogel, Daniel
University of Aberdeen The Distance Standard Deviation Edelmann, Dominic; Richards, Donald ; Vogel, Daniel Publication date: 2017 Document Version Other version Link to publication Citation for published version (APA): Edelmann, D., Richards, D., & Vogel, D. (2017). The Distance Standard Deviation. (pp. 1-27). ArXiv. https://arxiv.org/abs/1705.05777 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. ? Users may download and print one copy of any publication from the public portal for the purpose of private study or research. ? You may not further distribute the material or use it for any profit-making activity or commercial gain ? You may freely distribute the URL identifying the publication in the public portal ? Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Download date: 02. Oct. 2021 The Distance Standard Deviation Dominic Edelmann,∗ Donald Richards,y and Daniel Vogelz May 17, 2017 Abstract The distance standard deviation, which arises in distance correlation analy- sis of multivariate data, is studied as a measure of spread. New representations for the distance standard deviation are obtained in terms of Gini's mean differ- ence and in terms of the moments of spacings of order statistics. Inequalities for the distance variance are derived, proving that the distance standard deviation is bounded above by the classical standard deviation and by Gini's mean difference. -
Comparative Evaluation of Statistical Dependence Measures
University of Arkansas, Fayetteville ScholarWorks@UARK Theses and Dissertations 12-2020 Comparative Evaluation of Statistical Dependence Measures Eman Abdel Rahman Ibrahim University of Arkansas, Fayetteville Follow this and additional works at: https://scholarworks.uark.edu/etd Part of the Applied Statistics Commons Citation Ibrahim, E. A. (2020). Comparative Evaluation of Statistical Dependence Measures. Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/3903 This Thesis is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of ScholarWorks@UARK. For more information, please contact [email protected]. Comparative Evaluation of Statistical Dependence Measures A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Statistics and Analytics by Eman Abdel Rahman Ibrahim University of Arkansas Bachelor of Arts in Mathematics, 2015 December 2020 University of Arkansas This thesis is approved for recommendation to the Graduate Council. ______________________________ Qingyang Zhang, PhD. Thesis Director _______________________________ _____________________________ Mark E. Arnold, PhD. Giovanni Petris, PhD. Committee Member Committee Member Abstract Measuring and testing dependence between random variables is of great importance in many scientific fields. In the case of linearly correlated variables, Pearson’s correlation coefficient is a commonly used measure of the correlation -
Level Sets Based Distances for Probability Measures and Ensembles with Applications Arxiv:1504.01664V1 [Stat.ME] 7 Apr 2015
Level Sets Based Distances for Probability Measures and Ensembles with Applications Alberto Mu~noz1, Gabriel Martos1 and Javier Gonz´alez2 1Department of Statistics, University Carlos III of Madrid Spain. C/ Madrid, 126 - 28903, Getafe (Madrid), Spain. [email protected], [email protected] 2Sheffield Institute for Translational Neuroscience, Department of Computer Science, University of Sheffield. Glossop Road S10 2HQ, Sheffield, UK. [email protected] ABSTRACT In this paper we study Probability Measures (PM) from a functional point of view: we show that PMs can be considered as functionals (generalized func- tions) that belong to some functional space endowed with an inner product. This approach allows us to introduce a new family of distances for PMs, based on the action of the PM functionals on `interesting' functions of the sample. We propose a specific (non parametric) metric for PMs belonging to this class, arXiv:1504.01664v1 [stat.ME] 7 Apr 2015 based on the estimation of density level sets. Some real and simulated data sets are used to measure the performance of the proposed distance against a battery of distances widely used in Statistics and related areas. 1 Introduction Probability metrics, also known as statistical distances, are of fundamental importance in Statistics. In essence, a probability metric it is a measure that quantifies how (dis)similar are two random quantities, in particular two probability measures (PM). Typical examples of the use of probability metrics in Statistics are homogeneity, independence and goodness of fit tests. For instance there are some goodness of fit tests based on the use of the χ2 distance and others that use the Kolmogorov-Smirnoff statistics, which corresponds to the choice of the supremum distance between two PMs.