English
Related papers

Related papers: Approximative Covariance Interpolation

200 papers

Cross-spectral analysis is a mathematical tool for extracting the power spectral density of a correlated signal from two time series in the presence of uncorrelated interfering signals. We demonstrate and explain a set of conditions where…

Instrumentation and Detectors · Physics 2013-07-26 Craig W. Nelson , Archita Hati , David A. Howe

We propose and study a general quasi-interpolation framework for stochastic function approximation, which stems and draws motivation from convolution-type solutions for certain practical weighted variational problems. We obtain our…

Numerical Analysis · Mathematics 2025-12-24 Wenwu Gao , Le Hu , Xingping Sun , Xuan Zhou

Inference in graphical models consists of repeatedly multiplying and summing out potentials. It is generally intractable because the derived potentials obtained in this way can be exponentially large. Approximate inference techniques such…

Artificial Intelligence · Computer Science 2012-02-20 Vibhav Gogate , Pedro Domingos

The use of sparse precision (inverse covariance) matrices has become popular because they allow for efficient algorithms for joint inference in high-dimensional models. Many applications require the computation of certain elements of the…

Computation · Statistics 2017-12-06 Per Sidén , Finn Lindgren , David Bolin , Mattias Villani

Variational methods are widely used for approximate posterior inference. However, their use is typically limited to families of distributions that enjoy particular conjugacy properties. To circumvent this limitation, we propose a family of…

Machine Learning · Computer Science 2012-06-22 Samuel Gershman , Matt Hoffman , David Blei

The paper discusses the relationships between electrical and affine differential geometry quantities, establishing a link between frequency and time derivatives of voltage, through the utilization of affine geometric invariants. Based on…

Differential Geometry · Mathematics 2024-09-26 Ali Alshawabkeh , Georgios Tzounas , Angel Molina-Garcia , Federico Milano

We present several natural notions of distance between spectral density functions of (discrete-time) random processes. They are motivated by certain filtering problems. First we quantify the degradation of performance of a predictor which…

Optimization and Control · Mathematics 2008-07-19 Tryphon T. Georgiou

We report a numerical calculation of the two-photon absorption coefficient of electrons in a binding potential using the real-time real-space higher-order difference method. By introducing random vector averaging for the intermediate state,…

Materials Science · Physics 2009-10-31 Yoshiyuki Kurokawa , Shintaro Nomura , Tadashi Takemori , Yoshinobu Aoyagi

Efficiently performing predictive studies of irradiated particle-laden turbulent flows has the potential of providing significant contributions towards better understanding and optimizing, for example, concentrated solar power systems. As…

Computational Physics · Physics 2018-08-20 Hillary R. Fairbanks , Lluis Jofre , Gianluca Geraci , Gianluca Iaccarino , Alireza Doostan

Auto- and cross-spectral density functions for dynamic {random} fields and power are derived. These are based on first- and second-order Pad\'{e} approximants of correlation functions expanded in terms of spectral moments. The second-order…

Classical Physics · Physics 2024-04-04 Luk R. Arnaut

In this paper, we concentrate on new methodologies for copulas introduced and developed by Joe, Cooke, Bedford, Kurowica, Daneshkhah and others on the new class of graphical models called vines as a way of constructing higher dimensional…

Computation · Statistics 2012-10-30 Alireza Daneshkhah , Golamali Parham , Omid Chatrabgoun , M. Jokar

The maximum entropy ansatz, as it is often invoked in the context of time-series analysis, suggests the selection of a power spectrum which is consistent with autocorrelation data and corresponds to a random process least predictable from…

Probability · Mathematics 2008-07-19 Tryphon T. Georgiou

We want to approximate general multivariate probability density functions by deterministic sample sets. For optimal sampling, the closeness to the given continuous density has to be assessed. This is a difficult challenge in multivariate…

Systems and Control · Electrical Eng. & Systems 2020-01-01 Uwe D. Hanebeck

The effort to generate matrix exponentials and associated differentials, required to determine the time evolution of quantum systems, frequently constrains the evaluation of problems in quantum control theory, variational circuit…

Quantum Physics · Physics 2025-02-14 Michael Schilling , Francesco Preti , Matthias M. Müller , Tommaso Calarco , Felix Motzoi

We propose AAA rational approximation as a method for interpolating or approximating smooth functions from equispaced data samples. Although it is always better to approximate from large numbers of samples if they are available, whether…

Numerical Analysis · Mathematics 2022-07-26 Daan Huybrechs , Lloyd N. Trefethen

The subject of the present study is the Monte Carlo path-integral evaluation of the moments of spectral functions. Such moments can be computed by formal differentiation of certain estimating functionals that are infinitely-differentiable…

Statistical Mechanics · Physics 2009-11-11 Cristian Predescu

Direction of Arrival (DOA) estimation is a fundamental problem in signal processing. Diffuse sources, whose power density cannot be represented with a single angular coordinate, are usually characterized based on prior assumptions, which…

Signal Processing · Electrical Eng. & Systems 2025-12-18 Colin Cros , Laurent Ferro-Famil

We develop an interpolation-based framework for noisy linear systems with unknown system matrix with bounded norm (implying bounded growth or non-increasing energy), and bounded process noise energy. The proposed approach characterizes all…

Systems and Control · Electrical Eng. & Systems 2025-11-17 Martina Vanelli , Nima Monshizadeh , Julien M. Hendrickx

We present an analytic method for calculating spectral densities of empirical covariance matrices for correlated data. In this approach the data is represented as a rectangular random matrix whose columns correspond to sampled states of the…

Data Analysis, Statistics and Probability · Physics 2010-01-15 Zdzislaw Burda , Andrzej Goerlich , Bartlomiej Waclaw

We prove a.s. (almost sure) unisolvency of interpolation by continuous random sampling with respect to any given density, in spaces of multivariate a.e. (almost everywhere) analytic functions. Examples are given concerning polynomial and…

Numerical Analysis · Mathematics 2023-03-27 Francesco Dell'Accio , Alvise Sommariva , Marco Vianello