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1,241 Results Found

  • Article
  • Open Access
544 Views
13 Pages

8 March 2026

This study quantitatively approximates the unit operator using three types of multivariate, overactivated, and spiked convolution operators. The core of these operators is a multivariate “cusp” kernel, which acts as a novel, compact-suppo...

(This article belongs to the Special Issue New Perspectives in Operator Theory and Functional Analysis)
  • Feature Paper
  • Article
  • Open Access
1 Citations
1,255 Views
26 Pages

29 August 2024

Here we study the quantitative multivariate approximation of perturbed hyperbolic tangent-activated singular integral operators to the unit operator. The engaged neural network activation function is both parametrized and deformed, and the related ke...

  • Article
  • Open Access
1 Citations
1,629 Views
18 Pages

28 December 2023

In this article, we employ the uniform and Lp, 1≤p<∞ approximation properties of general smooth multivariate singular integral operators over RN, N≥1. It is a trigonometric relief approach with detailed applications to the correspondin...

  • Article
  • Open Access
2 Citations
1,175 Views
35 Pages

11 November 2024

In this article, we introduce, for the first time, multivariate symmetrized and perturbed hyperbolic tangent-activated convolution-type operators in three forms. We present their approximation properties, that is, their quantitative convergence to th...

(This article belongs to the Special Issue Theory and Application of Integral Inequalities)
  • Article
  • Open Access
3 Citations
1,615 Views
27 Pages

29 January 2025

This paper deals with a family of normalized multivariate neural network (MNN) operators of complex-valued continuous functions for a multivariate context on a box of RN¯, N¯∈N. Moreover, we consider the case of approximation employing...

(This article belongs to the Special Issue Approximation Theory and Applications)
  • Feature Paper
  • Article
  • Open Access
3 Citations
1,031 Views
25 Pages

29 November 2024

In this article, we study the multivariate quantitative smooth approximation under differentiation of functions. The approximators here are multivariate neural network operators activated by the symmetrized and perturbed hyperbolic tangent activation...

  • Article
  • Open Access
398 Views
15 Pages

18 March 2026

In this work we study the univariate and multivariate quantitative approximation by multi-composite Kantorovich–Choquet-type quasi-interpolation neural network operators with respect to the supremum norm. This is achieved with rates via the fir...

  • Article
  • Open Access
781 Views
46 Pages

9 May 2026

In this study, we develop a class of multivariate HHC-type operators generated by adjustable half-hyperbolic tangent activation functions and a symmetrized kernel structure. The analysis is carried out within the classical framework of positive linea...

(This article belongs to the Special Issue Applications Based on AI in Mathematics and Asymmetry/Symmetry)
  • Article
  • Open Access
1 Citations
2,867 Views
17 Pages

18 April 2022

We develop a technique for obtaining the fourth moment bound on the normal approximation of F, where F is an Rd-valued random vector whose components are functionals of Gaussian fields. This study transcends the case of vectors of multiple stochastic...

(This article belongs to the Special Issue Probability, Stochastic Processes and Optimization)
  • Article
  • Open Access
3 Citations
7,897 Views
15 Pages

6 April 2011

In the present paper, we propose a large sample asymptotic approximation for the sampling and posterior distributions of differential entropy when the sample is composed of independent and identically distributed realization of a multivariate normal...

  • Feature Paper
  • Article
  • Open Access
1 Citations
1,461 Views
17 Pages

21 November 2023

Considering the stability and safety of industrial production, the open-loop system cannot meet the requirements of industrial production, so more and more attention has been paid to multivariable closed-loop system identification. This study focuses...

(This article belongs to the Section Process Control, Modeling and Optimization)
  • Article
  • Open Access
6 Citations
4,433 Views
28 Pages

This study introduces a multivariate extension to the class of stochastic volatility models, employing integrated nested Laplace approximations (INLA) for estimation. Bayesian methods for estimating stochastic volatility models through Markov Chain M...

  • Article
  • Open Access
1,212 Views
20 Pages

15 May 2024

This paper examines the tractability of multivariate approximation problems under the normalized error criterion for a zero-mean Gaussian measure in an average-case setting. The Gaussian measure is associated with a covariance kernel, which is repres...

(This article belongs to the Special Issue Numerical Computation, Approximation of Functions and Applied Mathematics, 2nd Edition)
  • Article
  • Open Access
22 Citations
10,570 Views
41 Pages

13 April 2023

We present a simple method to approximate the Fisher–Rao distance between multivariate normal distributions based on discretizing curves joining normal distributions and approximating the Fisher–Rao distances between successive nearby nor...

(This article belongs to the Special Issue Information Geometry and Its Applications)
  • Article
  • Open Access
69 Views
35 Pages

5 November 2026

Unsupervised feature selection seeks to identify informative, nonredundant features without using class labels. Motivated by Fano’s inequality, we use the entropy of the selected feature subset as a task-agnostic heuristic for its information c...

(This article belongs to the Special Issue Rethinking Feature Selection Benchmarks: Hardness, Taxonomies, and Community-Driven Evaluation)
  • Article
  • Open Access
3 Citations
1,911 Views
25 Pages

Neural Network Approximation for Time Splitting Random Functions

  • George A. Anastassiou and
  • Dimitra Kouloumpou

In this article we present the multivariate approximation of time splitting random functions defined on a box or RN,N∈N, by neural network operators of quasi-interpolation type. We achieve these approximations by obtaining quantitative-type Jack...

(This article belongs to the Section E5: Financial Mathematics)
  • Article
  • Open Access
5 Citations
4,353 Views
39 Pages

26 January 2024

A system of simultaneous multi-variable nonlinear equations can be solved by Newton’s method with local q-quadratic convergence if the Jacobian is analytically available. If this is not the case, then quasi-Newton methods with local q-superline...

  • Feature Paper
  • Article
  • Open Access
908 Views
23 Pages

27 February 2026

The Taylor approximation theorem is a fundamental tool in numerical analysis, providing a local polynomial representation of smooth functions. In practical computations, a function f is approximated by a finite Taylor polynomial Pn, and controlling t...

(This article belongs to the Special Issue Advanced Numerical Methods for Differential Equations: Recent Developments, Analysis and Applications)
  • Article
  • Open Access
12 Citations
5,063 Views
23 Pages

12 June 2019

This work suggests a solution for the output reference model (ORM) tracking control problem, based on approximate dynamic programming. General nonlinear systems are included in a control system (CS) and subjected to state feedback. By linear ORM sele...

(This article belongs to the Special Issue Algorithms for PID Controller 2019)
  • Article
  • Open Access
1 Citations
1,567 Views
13 Pages

17 June 2023

This paper studies the uniqueness of the bounded solution to a new Cauchy problem of the fractional nonlinear partial integro-differential equation based on the multivariate Mittag–Leffler function as well as Banach’s contractive principl...

(This article belongs to the Special Issue Fractional Calculus and Mathematical Applications)
  • Article
  • Open Access
1 Citations
3,797 Views
19 Pages

6 July 2020

Information causality measures have proven to be very effective in uncovering the connectivity patterns of multivariate systems. The non-uniform embedding (NUE) scheme has been developed to address the “curse of dimensionality”, since the...

(This article belongs to the Special Issue Information Theory and Economic Network)
  • Article
  • Open Access
1 Citations
1,057 Views
17 Pages

5 November 2025

Modeling loss data is a crucial aspect of actuarial science. In the insurance industry, small claims occur frequently, while large claims are rare. Traditional heavy-tail distributions, such as Weibull, Log-Normal, and Inverse Gaussian distributions,...

  • Article
  • Open Access
4 Citations
1,451 Views
14 Pages

22 August 2023

In this paper, we study the probabilistic Gel’fand N,δ-width of multivariate Sobolev spaces MW2rTd with mixed derivative that are equipped with Gaussian measure μ in LqTd. The sharp asymptotic estimates ar...

(This article belongs to the Special Issue Advanced Approximation Techniques and Their Applications)
  • Article
  • Open Access
3 Citations
2,555 Views
29 Pages

17 September 2024

Accurate forecasting of high-resolution particulate matter 2.5 (PM2.5) levels is essential for the development of public health policy. However, datasets used for this purpose often contain missing observations. This study presents a two-stage approa...

(This article belongs to the Section D1: Probability and Statistics)
  • Article
  • Open Access
8 Citations
8,176 Views
29 Pages

29 July 2015

Multivariate nonlinear mixed-effects models (MNLMM) have received increasing use due to their flexibility for analyzing multi-outcome longitudinal data following possibly nonlinear profiles. This paper presents and compares five different iterative a...

(This article belongs to the Special Issue Inductive Statistical Methods)
  • Article
  • Open Access
1 Citations
1,973 Views
12 Pages

Kantorovich Version of Vector-Valued Shepard Operators

  • Oktay Duman,
  • Biancamaria Della Vecchia and
  • Esra Erkus-Duman

9 March 2024

In the present work, in order to approximate integrable vector-valued functions, we study the Kantorovich version of vector-valued Shepard operators. We also display some applications supporting our results by using parametric plots of a surface and...

  • Article
  • Open Access
43 Citations
5,454 Views
23 Pages

Analysis of Transient Thermal Distribution in a Convective–Radiative Moving Rod Using Two-Dimensional Differential Transform Method with Multivariate Pade Approximant

  • Ganeshappa Sowmya,
  • Ioannis E. Sarris,
  • Chandra Sen Vishalakshi,
  • Ravikumar Shashikala Varun Kumar and
  • Ballajja Chandrappa Prasannakumara

26 September 2021

The transient temperature distribution through a convective-radiative moving rod with temperature-dependent internal heat generation and non-linearly varying temperature-dependent thermal conductivity is elaborated in this investigation. Symmetries a...

(This article belongs to the Special Issue Solid Mechanics and Mechanical Mechanics)
  • Article
  • Open Access
4 Citations
2,224 Views
15 Pages

28 June 2022

This paper aims at presenting a novel effective approach to probabilistic analysis of distribution power grid with high penetration of PV sources. The novel method adopts a Gaussian Mixture Model for reproducing the uncertainty of correlated PV sourc...

(This article belongs to the Section A2: Solar Energy and Photovoltaic Systems)
  • Article
  • Open Access
5 Citations
3,634 Views
20 Pages

24 July 2020

In some applications, one is interested in reconstructing a function f from its Fourier series coefficients. The problem is that the Fourier series is slowly convergent if the function is non-periodic, or is non-smooth. In this paper, we suggest a me...

(This article belongs to the Special Issue Nonlinear Analysis and Optimization with Applications)
  • Article
  • Open Access
6 Citations
3,383 Views
20 Pages

Nonlinear Profile Monitoring Using Spline Functions

  • Hua Xin,
  • Wan-Ju Hsieh,
  • Yuhlong Lio and
  • Tzong-Ru Tsai

15 September 2020

In this study, two new integrated control charts, named T2-MAE chart and MS-MAE chart, are introduced for monitoring the quality of a process when the mathematical form of nonlinear profile model for quality measure is complicated and unable to be sp...

(This article belongs to the Special Issue Recent Advances of Computational Statistics in Industry and Business)
  • Article
  • Open Access
4 Citations
5,145 Views
28 Pages

4 February 2024

The complexity of estimating multivariate GARCH models increases significantly with the increase in the number of asset series. To address this issue, we propose a general regularization framework for high-dimensional GARCH models with BEKK represent...

(This article belongs to the Special Issue Risks Journal: A Decade of Advancing Knowledge and Shaping the Future)
  • Article
  • Open Access
2 Citations
1,933 Views
17 Pages

5 February 2024

We investigate L2-approximation problems in the worst case setting in the weighted Hilbert spaces H(KRd,α,γ) with weights Rd,α,γ under parameters 1≥γ1≥γ2≥⋯≥0 and 1<α1≤α2≤;...

(This article belongs to the Special Issue Advanced Approximation Techniques and Their Applications)
  • Article
  • Open Access
1,943 Views
24 Pages

An efficient linearization method for solving a system of nonlinear equations was developed, showing good stability and convergence properties. It uses an unconventional and simple strategy to improve the performance of classic methods by a full-rank...

  • Article
  • Open Access
750 Views
19 Pages

16 July 2026

The development of regression models for composite distributions has received insufficient attention in the literature. The purpose of this research is to provide maximum likelihood (ML) and approximate Bayesian computation (ABC) estimators for the p...

(This article belongs to the Special Issue Advances in Risk Models and Actuarial Science)
  • Article
  • Open Access
19 Citations
4,408 Views
18 Pages

An Approximation for Metal-Oxide Sensor Calibration for Air Quality Monitoring Using Multivariable Statistical Analysis

  • Diego Sales-Lérida,
  • Alfonso J. Bello,
  • Alberto Sánchez-Alzola and
  • Pedro Manuel Martínez-Jiménez

13 July 2021

Good air quality is essential for both human beings and the environment in general. The three most harmful air pollutants are nitrogen dioxide (NO2), ozone (O3) and particulate matter. Due to the high cost of monitoring stations, few examples of this...

(This article belongs to the Collection Sensors for Air Quality Monitoring)
  • Article
  • Open Access
5 Citations
1,792 Views
21 Pages

Bayesian Discrepancy Measure: Higher-Order and Skewed Approximations

  • Elena Bortolato,
  • Francesco Bertolino,
  • Monica Musio and
  • Laura Ventura

20 June 2025

The aim of this paper is to discuss both higher-order asymptotic expansions and skewed approximations for the Bayesian discrepancy measure used in testing precise statistical hypotheses. In particular, we derive results on third-order asymptotic appr...

  • Article
  • Open Access
22 Citations
8,697 Views
14 Pages

Expansion of the Kullback-Leibler Divergence, and a New Class of Information Metrics

  • David J. Galas,
  • Gregory Dewey,
  • James Kunert-Graf and
  • Nikita A. Sakhanenko

1 April 2017

Inferring and comparing complex, multivariable probability density functions is fundamental to problems in several fields, including probabilistic learning, network theory, and data analysis. Classification and prediction are the two faces of this cl...

  • Article
  • Open Access
14 Citations
4,543 Views
12 Pages

14 March 2019

It is well known that feed-forward neural networks can be used for approximation to functions based on an appropriate activation function. In this paper, employing a new sigmoidal function with a parameter for an activation function, we consider a co...

  • Article
  • Open Access
16 Citations
4,441 Views
21 Pages

1 July 2019

The reliability-based sensitivity analysis requires to recursively evaluate a multivariate structural model for many failure probability levels. This is in general a computationally intensive task due to irregular integrations used to define the stru...

(This article belongs to the Special Issue Intelligent Tools and Applications in Engineering and Mathematics)
  • Article
  • Open Access
31 Citations
10,243 Views
14 Pages

Insights into Entropy as a Measure of Multivariate Variability

  • Badong Chen,
  • Jianji Wang,
  • Haiquan Zhao and
  • Jose C. Principe

20 May 2016

Entropy has been widely employed as a measure of variability for problems, such as machine learning and signal processing. In this paper, we provide some new insights into the behaviors of entropy as a measure of multivariate variability. The relatio...

(This article belongs to the Special Issue Information: Meanings and Interpretations)
  • Article
  • Open Access
5 Citations
2,691 Views
14 Pages

10 March 2021

This manuscript addresses a new multivariate generalized predictive control strategy using the least squares support vector machine for parabolic distributed parameter systems. First, a set of proper orthogonal decomposition-based spatial basis funct...

(This article belongs to the Special Issue Symmetry in Optimization and Control with Real World Applications)
  • Article
  • Open Access
2 Citations
3,412 Views
27 Pages

18 February 2019

This article provides a review of the saddlepoint approximation for a M-statistic of a sample of nonnegative random variables with fixed sum. The sample vector follows the multinomial, the multivariate hypergeometric, the multivariate Polya or the Di...

  • Article
  • Open Access
4 Citations
2,240 Views
22 Pages

17 July 2023

In this article, we give the sharp bounds of probabilistic Kolmogorov N,δ-widths and probabilistic linear N,δ-widths of the multivariate Sobolev space W2A with common smoothness on a Sq norm equipped with the Gaussian measure μ, where...

(This article belongs to the Special Issue Advanced Approximation Techniques and Their Applications)
  • Article
  • Open Access
7 Citations
4,309 Views
19 Pages

There has been a considerable evolution of the theory of fractal interpolation function (FIF) over the last three decades. Recently, we introduced a multivariate analogue of a special class of FIFs, which is referred to as α-fractal functions, from t...

(This article belongs to the Special Issue Fractal Functions and Applications)
  • Article
  • Open Access
43 Citations
4,173 Views
17 Pages

15 October 2018

In order to improve the accuracy of wind power prediction (WPP), we propose a WPP based on multivariate phase space reconstruction (MPSR) and multivariate linear regression (MLR). Firstly, the multivariate time series (TS) are constructed through rea...

(This article belongs to the Special Issue Power Electronics in Renewable Energy Systems)
  • Article
  • Open Access
4 Citations
2,332 Views
18 Pages

Least Squares Approximation of Flatness on Riemannian Manifolds

  • Iulia Hirica,
  • Constantin Udriste,
  • Gabriel Pripoae and
  • Ionel Tevy

13 October 2020

The purpose of this paper is fourfold: (i) to introduce and study the Euler–Lagrange prolongations of flatness PDEs solutions (best approximation of flatness) via associated least squares Lagrangian densities and integral functionals on Riemann...

  • Article
  • Open Access
18 Citations
5,441 Views
22 Pages

14 July 2016

The paper develops applications of symmetric orbit functions, known from irreducible representations of simple Lie groups, in numerical analysis. It is shown that these functions have remarkable properties which yield to cubature formulas, approximat...

(This article belongs to the Special Issue Symmetry in Orthogonal Polynomials)
  • Article
  • Open Access
13 Citations
2,452 Views
17 Pages

This work provides exact and analytical approximate solutions for a non-linear time-fractional generalized biology population model (FGBPM) with suitable initial data under the time-Caputo fractional derivative, in view of a novel effective and appli...

(This article belongs to the Special Issue Recent Advances in Fractional Differential Equations and Their Applications)

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