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Anomaly Detection in multivariate time series is a major problem in many fields. Due to their nature, anomalies sparsely occur in real data, thus making the task of anomaly detection a challenging problem for classification algorithms to…

Machine Learning · Computer Science 2023-08-08 Anastasios Iliopoulos , John Violos , Christos Diou , Iraklis Varlamis

Smoothing filter is the method of choice for image preprocessing and pattern recognition. We present a new concurrent method for smoothing 2D object in binary case. Proposed method provides a parallel computation while preserving the…

Distributed, Parallel, and Cluster Computing · Computer Science 2016-04-01 Ramzi Mahmoudi , Mohamed Akil

B-spline-based hidden Markov models employ B-splines to specify the emission distributions, offering a more flexible modelling approach to data than conventional parametric HMMs. We introduce a Bayesian framework for inference, enabling the…

Methodology · Statistics 2023-10-03 Sida Chen , Bärbel Finkenstädt Rand

Google uses continuous streams of data from industry partners in order to deliver accurate results to users. Unexpected drops in traffic can be an indication of an underlying issue and may be an early warning that remedial action may be…

Machine Learning · Statistics 2017-08-15 Dominique T. Shipmon , Jason M. Gurevitch , Paolo M. Piselli , Stephen T. Edwards

This paper considers approximate smoothing for discretely observed non-linear stochastic differential equations. The problem is tackled by developing methods for linearising stochastic differential equations with respect to an arbitrary…

Methodology · Statistics 2019-01-21 Filip Tronarp , Simo Särkkä

Smoothing is a specialized form of Bayesian inference for state-space models that characterizes the posterior distribution of a collection of states given an associated sequence of observations. Ramgraber et al. (2023) proposes a general…

Methodology · Statistics 2023-11-23 Maximilian Ramgraber , Ricardo Baptista , Dennis McLaughlin , Youssef Marzouk

We propose a nonparametric method for detecting nonlinear causal relationship within a set of multidimensional discrete time series, by using sparse additive models (SpAMs). We show that, when the input to the SpAM is a $\beta$-mixing time…

Machine Learning · Statistics 2018-04-27 Yingxiang Yang , Adams Wei Yu , Zhaoran Wang , Tuo Zhao

Smoothing algorithms for state-space models, i.e., fixed-interval smoothing, fixed-lag smoothing, and two-filter formula for smoothing, are examined using real examples. For linear and Gaussian state-space models, it is observed that…

Computation · Statistics 2023-07-10 G. Kitagawa

Anomaly detection in spatiotemporal data is a challenging problem encountered in a variety of applications including hyperspectral imaging, video surveillance and urban traffic monitoring. In the case of urban traffic data, anomalies refer…

Signal Processing · Electrical Eng. & Systems 2021-03-02 Seyyid Emre Sofuoglu , Selin Aviyente

This paper presents a method for calculating the smoothed state distribution for Jump Markov Linear Systems. More specifically, the paper details a novel two-filter smoother that provides closed-form expressions for the smoothed hybrid…

Methodology · Statistics 2020-04-21 Mark P. Balenzuela , Adrian G. Wills , Christopher Renton , Brett Ninness

This paper constructs an ensemble-based sampling smoother for four-dimensional data assimilation using a Hybrid/Hamiltonian Monte-Carlo approach. The smoother samples efficiently from the posterior probability density of the solution at the…

Numerical Analysis · Computer Science 2015-05-19 Ahmed Attia , Vishwas Rao , Adrian Sandu

This paper describes a new method, HMM gauge likelihood analysis, or GLA, of detecting anomalies in discrete time series using Hidden Markov Models and clustering. At the center of the method lies the comparison of subsequences. To achieve…

Machine Learning · Computer Science 2020-09-22 Boris Lorbeer , Tanja Deutsch , Peter Ruppel , Axel Küpper

For some special data in reality, such as the genetic data, adjacent genes may have the similar function. Thus ensuring the smoothness between adjacent genes is highly necessary. But, in this case, the standard lasso penalty just doesn't…

Methodology · Statistics 2022-09-29 Xin Xin , Boyi Xie , Yunhai Xiao

For challenging state estimation problems arising in domains like vision and robotics, particle-based representations attractively enable temporal reasoning about multiple posterior modes. Particle smoothers offer the potential for more…

Machine Learning · Computer Science 2025-02-18 Ali Younis , Erik B. Sudderth

Monitoring of hybrid systems attracts both scientific and practical attention. However, monitoring algorithms suffer from the methodological difficulty of only observing sampled discrete-time signals, while real behaviors are…

Systems and Control · Electrical Eng. & Systems 2024-07-26 Masaki Waga , Étienne André , Ichiro Hasuo

We consider a linear regression problem in a high dimensional setting where the number of covariates $p$ can be much larger than the sample size $n$. In such a situation, one often assumes sparsity of the regression vector, \textit i.e.,…

Statistics Theory · Mathematics 2011-10-12 Mohamed Hebiri , Sara A. Van De Geer

Standard Bayesian Optimization (BO) assumes uniform smoothness across the search space an assumption violated in multi-regime problems such as molecular conformation search through distinct energy basins or drug discovery across…

Machine Learning · Computer Science 2026-01-29 Yan Zhang , Xuefeng Liu , Sipeng Chen , Sascha Ranftl , Chong Liu , Shibo Li

Time series analysis is used to understand and predict dynamic processes, including evolving demands in business, weather, markets, and biological rhythms. Exponential smoothing is used in all these domains to obtain simple interpretable…

Machine Learning · Statistics 2017-10-02 Avner Abrami , Aleksandr Y. Aravkin , Younghun Kim

In this study, we investigate the effectiveness of advanced feature engineering and hybrid model architectures for anomaly detection in a multivariate industrial time series, focusing on a steam turbine system. We evaluate the impact of…

Machine Learning · Computer Science 2025-10-31 Emilio Mastriani , Alessandro Costa , Federico Incardona , Kevin Munari , Sebastiano Spinello

In this paper, we consider the filtering and smoothing recursions in nonparametric finite state space hidden Markov models (HMMs) when the parameters of the model are unknown and replaced by estimators. We provide an explicit and time…

Statistics Theory · Mathematics 2015-07-24 Yohann De Castro , Elisabeth Gassiat , Sylvain Le Corff