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Unsupervised fault detection in multivariate time series plays a vital role in ensuring the stable operation of complex systems. Traditional methods often assume that normal data follow a single Gaussian distribution and identify anomalies…

Machine Learning · Computer Science 2025-07-01 Hong Liu , Xiuxiu Qiu , Yiming Shi , Miao Xu , Zelin Zang , Zhen Lei

We discuss the Gaussian graphical model (GGM; an undirected network of partial correlation coefficients) and detail its utility as an exploratory data analysis tool. The GGM shows which variables predict one-another, allows for sparse…

Methodology · Statistics 2018-02-09 Sacha Epskamp , Lourens J. Waldorp , René Mõttus , Denny Borsboom

We explore the use of galaxy bispectra with multitracer technique as a possible probe of primordial non-Gaussianities. We forecast future constraints on non-linearity parameters, $f_{\rm NL}^{\rm eq}$ and $f_{\rm NL}^{\rm orth}$, which…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-12 Daisuke Yamauchi , Shuichiro Yokoyama , Keitaro Takahashi

High dimensional piecewise stationary graphical models represent a versatile class for modelling time varying networks arising in diverse application areas, including biology, economics, and social sciences. There has been recent work in…

Machine Learning · Statistics 2018-06-21 Hossein Keshavarz , George Michailidis , Yves Atchade

Standard sparse pseudo-input approximations to the Gaussian process (GP) cannot handle complex functions well. Sparse spectrum alternatives attempt to answer this but are known to over-fit. We suggest the use of variational inference for…

Machine Learning · Statistics 2015-03-23 Yarin Gal , Richard Turner

We present the application of the pseudo-spectrum method to galaxy-galaxy lensing. We derive explicit expressions for the pseudo-spectrum analysis of the galaxy-shear cross spectrum, which is the Fourier space counterpart of the stacked…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-25 Chiaki Hikage , Masamune Oguri

We introduce a wavelet-based model of local stationarity. This model enlarges the class of locally stationary wavelet processes and contains processes whose spectral density function may change very suddenly in time. A notion of…

Statistics Theory · Mathematics 2008-08-12 Sébastien Van Bellegem , Rainer von Sachs

Taking a multidimensional time-homogeneous dynamical system and adding a randomly perturbed time-dependent deterministic signal to some of its components gives rise to a high-dimensional system of stochastic differential equations which is…

Statistics Theory · Mathematics 2019-08-02 Simon Holbach

Aperiodic variability is a characteristic feature of young stars, massive stars, and active galactic nuclei. With the recent proliferation of time domain surveys, it is increasingly essential to develop methods to quantify and analyze…

Instrumentation and Methods for Astrophysics · Physics 2026-04-01 Krzysztof Findeisen , Ann Marie Cody , Lynne Hillenbrand

The Gaussian phase noise of intensity time series is demonstrated to be drastically reduced when the raw voltage data are digitally filtered through an arbitrarily large number $n$ of orthornormal bandpass profiles (eigen-filters) sharing…

Instrumentation and Methods for Astrophysics · Physics 2020-08-26 Richard Lieu , Kristen Lackeos

Properties of data are frequently seen to vary depending on the sampled situations, which usually changes along a time evolution or owing to environmental effects. One way to analyze such data is to find invariances, or representative…

Machine Learning · Statistics 2012-09-26 Satoshi Hara , Takashi Washio

This paper addresses the issue of detecting change-points in multivariate time series. The proposed approach differs from existing counterparts by making only weak assumptions on both the change-points structure across series, and the…

Methodology · Statistics 2014-07-14 Flore Harlé , Florent Chatelain , Cédric Gouy-Pailler , Sophie Achard

A Gaussian process is proposed as a model for the posterior distribution of the local predictive ability of a model or expert, conditional on a vector of covariates, from historical predictions in the form of log predictive scores. Assuming…

Methodology · Statistics 2024-10-08 Oscar Oelrich , Mattias Villani

This paper is concerned with the problem of how to speed up computation for Gaussian process models trained on autocorrelated data. The Gaussian process model is a powerful tool commonly used in nonlinear regression applications. Standard…

Machine Learning · Computer Science 2025-12-03 Ahmadreza Chokhachian , Matthias Katzfuss , Yu Ding

Statistical inference for time series such as curve estimation for time-varying models or testing for existence of change-point have garnered significant attention. However, these works are generally restricted to the assumption of…

Statistics Theory · Mathematics 2024-08-08 Soham Bonnerjee , Sayar Karmakar , Wei Biao Wu

Understanding the time-varying structure of complex temporal systems is one of the main challenges of modern time series analysis. In this paper, we show that every uniformly-positive-definite-in-covariance and sufficiently short-range…

Statistics Theory · Mathematics 2023-04-25 Xiucai Ding , Zhou Zhou

A multi-output Gaussian process (GP) is introduced as a model for the joint posterior distribution of the local predictive ability of set of models and/or experts, conditional on a vector of covariates, from historical predictions in the…

Methodology · Statistics 2024-10-08 Oscar Oelrich , Mattias Villani

A class of multivariate spectral representations for real-valued nonstationary random variables is introduced, which is characterised by a general complex Gaussian distribution. In this way, the temporal signal properties -- harmonicity,…

Signal Processing · Electrical Eng. & Systems 2020-07-29 Bruno Scalzo , Ljubisa Stankovic , Danilo P. Mandic

We present an adaptation of the standard Grassberger-Proccacia (GP) algorithm for estimating the Correlation Dimension of a time series in a non subjective manner. The validity and accuracy of this approach is tested using different types…

Chaotic Dynamics · Physics 2008-11-26 K. P. Harikrishnan , R. Misra , G. Ambika , A. K. Kembhavi

Motivated by the analysis of spectrometric data, we introduce a Gaussian graphical model for learning the dependence structure among frequency bands of the infrared absorbance spectrum. The spectra are modeled as continuous functional data…