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Our work focuses on anomaly detection in cyber-physical systems. Prior literature has three limitations: (1) Failing to capture long-delayed patterns in system anomalies; (2) Ignoring dynamic changes in sensor connections; (3) The curse of…

Machine Learning · Computer Science 2023-02-28 Ehtesamul Azim , Dongjie Wang , Yanjie Fu

This paper proposes a flexible framework for inferring large-scale time-varying and time-lagged correlation networks from multivariate or high-dimensional non-stationary time series with piecewise smooth trends. Built on a novel and unified…

Methodology · Statistics 2023-02-13 Lujia Bai , Weichi Wu

Sensors are the key to environmental monitoring, which impart benefits to smart cities in many aspects, such as providing real-time air quality information to assist human decision-making. However, it is impractical to deploy massive…

Machine Learning · Computer Science 2024-04-24 Junfeng Hu , Yuxuan Liang , Zhencheng Fan , Li Liu , Yifang Yin , Roger Zimmermann

We describe a proof-of-concept development and application of a phase averaging technique to the nonlinear rotating shallow water equations on the sphere, discretised using compatible finite element methods. Phase averaging consists of…

Numerical Analysis · Mathematics 2023-05-15 Hiroe Yamazaki , Colin J Cotter , Beth Wingate

Many real-life signals are defined on spherical domains, in particular in geophysics and physics applications. In this work, we tackle the problem of extending the iterative filtering algorithm, developed for the decomposition of…

Numerical Analysis · Mathematics 2023-12-01 Giovanni Barbarino , Roberto Cavassi , Antonio Cicone

We present a nonparametric way to retrieve a system of differential equations in embedding space from a single time series. These equations can be treated with dynamical systems theory and allow for long term predictions. We demonstrate the…

Chaotic Dynamics · Physics 2009-11-10 Markus Abel , Karsten Ahnert , Juergen Kurths , Simon Mandelj

In this paper, we introduce a new wavelet tool for studying the degree of non-periodicity of time series that is based on some recently defined tools, such as the \textit{windowed scalogram} and the \textit{scale index}. It is especially…

Chaotic Dynamics · Physics 2020-05-29 Vicente J. Bolos , Rafael Benitez , Roman Ferrer

In several practical applications, particularly healthcare, clinical data of each patient is individually recorded in a database at irregular intervals as required. This causes a sparse and irregularly sampled time series, which makes it…

Machine Learning · Computer Science 2025-04-09 Mincheol Kim , Soo-Yong Shin

Time series forecasting is essential in a wide range of real world applications. Recently, frequency-domain methods have attracted increasing interest for their ability to capture global dependencies. However, when applied to non-stationary…

Machine Learning · Statistics 2026-02-09 Zhongde An , Jinhong You , Jiyanglin Li , Yiming Tang , Wen Li , Heming Du , Shouguo Du

Irregularly sampled time series data arise naturally in many application domains including biology, ecology, climate science, astronomy, and health. Such data represent fundamental challenges to many classical models from machine learning…

Machine Learning · Computer Science 2021-01-07 Satya Narayan Shukla , Benjamin M. Marlin

A framework is proposed for the unconditional generation of synthetic time series based on learning from a single sample in low-data regime case. The framework aims at capturing the distribution of patches in wavelet scalogram of time…

Signal Processing · Electrical Eng. & Systems 2022-11-07 Amir Kazemi , Hadi Meidani

The problem of denoising a one-dimensional signal possessing varying degrees of smoothness is ubiquitous in time-domain astronomy and astronomical spectroscopy. For example, in the time domain, an astronomical object may exhibit a smoothly…

Instrumentation and Methods for Astrophysics · Physics 2022-02-01 Collin A. Politsch , Jessi Cisewski-Kehe , Rupert A. C. Croft , Larry Wasserman

In this paper, we consider the nonstationary matrix-valued time series with common stochastic trends. Unlike the traditional factor analysis which flattens matrix observations into vectors, we adopt a matrix factor model in order to fully…

Econometrics · Economics 2025-08-25 Degui Li , Yayi Yan , Qiwei Yao

We present a new distribution-free conformal prediction algorithm for sequential data (e.g., time series), called the \textit{sequential predictive conformal inference} (\texttt{SPCI}). We specifically account for the nature that time…

Machine Learning · Statistics 2023-05-31 Chen Xu , Yao Xie

Stochastic differential equations (SDEs) provide a flexible framework for modeling temporal dynamics in partially observed systems. A central task is to calibrate such models from data, which requires inferring latent trajectories and…

Machine Learning · Statistics 2026-05-08 Yu Wang , Arnab Ganguly

This study suggests a stochastic model for time series of daily-zonal (circumpolar) mean stratospheric temperature at a given pressure level. It can be seen as an extension of previous studies which have developed stochastic models for…

Light curves of astrophysical objects frequently contain strictly periodic signals. In those cases we can use that property to aid the detrending algorithm to fully disentangle an unknown periodic signal and an unknown baseline signal with…

Instrumentation and Methods for Astrophysics · Physics 2019-05-01 Andrej Prsa , Moses Zhang , Mark Wells

Spatial-temporal graph modeling is an important task to analyze the spatial relations and temporal trends of components in a system. Existing approaches mostly capture the spatial dependency on a fixed graph structure, assuming that the…

Machine Learning · Computer Science 2019-06-04 Zonghan Wu , Shirui Pan , Guodong Long , Jing Jiang , Chengqi Zhang

We study the problem of recovering a globally consistent Euclidean embedding of data, given only a local distance graph and propose a method that optimally represents these distances. The method operates solely on a neighborhood graph…

Machine Learning · Computer Science 2026-05-20 Dimitris Arabadjis

Many measurements on soft condensed matter (e.g., biological and materials) systems track low-dimensional observables projected from the full system phase space as a function of time. Examples are dynamic structure factors, spectroscopic…

Statistical Mechanics · Physics 2021-02-03 Alessio Lapolla , Jeremy C. Smith , Aljaž Godec