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Real time sensor based applications in pervasive computing require edge deployable models to ensure low latency privacy and efficient interaction. A prime example is sensor based human activity recognition where models must balance accuracy…

Machine Learning · Computer Science 2026-03-30 Deepika Gurung , Lala Shakti Swarup Ray , Mengxi Liu , Bo Zhou , Paul Lukowicz

We study the minimax estimation of covariance eigenfunctions and eigenvalues in functional principal component analysis when $n$ trajectories are observed at $p$ common grid points with additive noise. We consider covariance kernels with…

Statistics Theory · Mathematics 2026-05-08 Nassim Bourarach , Franck Picard , Vincent Rivoirard , Angelina Roche

Studying time-dependent behavior in lasers is analytically difficult due to the saturating non-linearity inherent in the Maxwell-Bloch equations and numerically demanding because of the computational resources needed to discretize both time…

Optics · Physics 2015-12-23 O. Malik , K. G. Makris , H. E. Türeci

Simulating a Gaussian process requires sampling from a high-dimensional Gaussian distribution, which scales cubically with the number of sample locations. Spectral methods address this challenge by exploiting the Fourier representation,…

Machine Learning · Statistics 2026-02-27 Arsalan Jawaid , Abdullah Karatas , Jörg Seewig

Sparse non-Hermitian random matrices arise in the study of disordered physical systems with asymmetric local interactions, and have applications ranging from neural networks to ecosystem dynamics. The spectral characteristics of these…

Statistical Mechanics · Physics 2024-02-21 Fernando Lucas Metz , Izaak Neri , Tim Rogers

The aim of the paper is to understand how the inclusion of more and more time-scales into a stochastic stationary Markovian process affects its conditional probability. To this end, we consider two Gaussian processes: (i) a short-range…

Statistical Mechanics · Physics 2010-12-08 Salvatore Miccichè

We provide an overview of standard "projective" quantum measurements with the goal of elucidating connections between theory and experiment. We make use of a unitary "Stinespring" representation of measurements on a dilated Hilbert space…

Quantum Physics · Physics 2024-04-09 Diego Barberena , Aaron J. Friedman

The goal of this paper is to extend the nonparametric estimation of Impulse Response Functions (IRF) by means of local projections in the nonlinear dynamic framework. We discuss the existence of a nonlinear autoregressive representation for…

Econometrics · Economics 2025-08-26 Christian Gourieroux , Quinlan Lee

In this paper, we investigate the stationarity of stochastic processes in the fractional Fourier domains. We study the stationarity of a stochastic process after performing fractional Fourier transform (FRFT), and discrete fractional…

Complex Variables · Mathematics 2012-11-13 Ahmed El Shafie , Tamer Khattab

In this paper, we study the problem of adaptive estimation of the spectral density of a stationary Gaussian process. For this purpose, we consider a wavelet-based method which combines the ideas of wavelet approximation and estimation by…

Statistics Theory · Mathematics 2011-06-07 Jérémie Bigot , Rolando Biscay Lirio , Jean-Michel Loubes , Lilian Muniz Alvarez

We introduce a new class of spatial Cox processes driven by a Hilbert--valued random log--intensity. We adopt a parametric framework in the spectral domain, to estimate its spatial functional correlation structure. Specifically, we consider…

Methodology · Statistics 2021-03-11 M. P. Frías , A. Torres-Signes , M. D. Ruiz-Medina , J. Mateu

We show that a time series $x_t$ evolving by a non-local update rule $x_t = f (x_{t-n},x_{t-k})$ with two different delays $k<n$ can be mapped onto a local process in two dimensions with special time-delayed boundary conditions provided…

Statistical Mechanics · Physics 2010-01-02 Silvio R. Dahmen , Haye Hinrichsen , Wolfgang Kinzel

Spectral decomposition of dynamical systems is a popular methodology to investigate the fundamental qualitative and quantitative properties of these systems and their solutions. In this chapter, we consider a class of nonlinear cooperative…

Systems and Control · Computer Science 2019-04-23 Hossein K. Mousavi , Christoforos Somarakis , Qiyu Sun , Nader Motee

Markovian projections arise in problems where we aim to mimic the one-dimensional marginal laws of an It\^o semimartingale by using another It\^o process with Markovian dynamics. In applications, Markovian projections are useful in…

Probability · Mathematics 2025-11-25 Martin Larsson , Shukun Long

The characteristics of an x-ray spectrum can greatly influence imaging and related tasks. In practice, due to the pile-up effect of the detector, it's difficult to directly measure the spectrum of a CT scanner using an energy resolved…

Medical Physics · Physics 2015-03-09 Wei Zhao , Kai Niu , Sebastian Schafer , Kevin Royalty

Analytical results on the correlation functions of strongly correlated many-body systems are rare in the literature and their importance cannot be overstated. We present determinant representations for the space-, time-, and…

Strongly Correlated Electrons · Physics 2024-11-12 Ovidiu I. Patu , Andreas Klumper , Angela Foerster

Many recently proposed gradient projection algorithms with inertial extrapolation step for solving quasi-variational inequalities in Hilbert spaces are proven to be strongly convergent with no linear rate given when the cost operator is…

Optimization and Control · Mathematics 2024-04-23 Yonghong Yao , Lateef O. Jolaoso , Yekini Shehu

We introduce so-called super/sub-martingale projections as a family of endomorphisms defined on unions of Polish spaces. Such projections allow us to identify martingales as collections of transformations that relate path-valued random…

Quantum Physics · Physics 2026-02-04 Lane P. Hughston , Levent A. Mengütürk

Predictive equivalence in discrete stochastic processes have been applied with great success to identify randomness and structure in statistical physics and chaotic dynamical systems and to inferring hidden Markov models. We examine the…

Statistical Mechanics · Physics 2021-09-21 Samuel P. Loomis , James P. Crutchfield

Interpolatory projection methods for model reduction of nonparametric linear dynamical systems have been successfully extended to nonparametric bilinear dynamical systems. However, this is not the case for parametric bilinear systems. In…

Numerical Analysis · Mathematics 2017-12-21 Andrea Carracedo Rodriguez , Serkan Gugercin , Jeff Borggaard