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319 Results Found

  • Article
  • Open Access
1 Citations
1,466 Views
22 Pages

4 December 2024

In this paper, we deal with the properties and applications of a nonlinear scalarization function for sets by using the Minkowski difference. Under some suitable assumptions, the continuity and convexity concerned with the nonlinear scalarization fun...

(This article belongs to the Special Issue Fixed Point, Optimization, and Applications II)
  • Article
  • Open Access
1 Citations
2,888 Views
10 Pages

11 October 2019

The connectedness and path connectedness of the solution sets to vector optimization problems is an important and interesting study in optimization theories and applications. Most papers involving the direction established the connectedness and conne...

(This article belongs to the Special Issue Fixed Point, Optimization, and Applications)
  • Article
  • Open Access
1 Citations
1,024 Views
17 Pages

4 July 2025

Sustainable economic decision making increasingly requires robust methodologies capable of withstanding deep uncertainty, particularly in volatile financial and resource-constrained environments. This paper introduces a unified optimization framework...

(This article belongs to the Section Economic and Business Aspects of Sustainability)
  • Article
  • Open Access
6 Citations
2,628 Views
13 Pages

18 September 2022

This paper proposes a new fractional-order model reference adaptive control (FOMRAC) framework for a fractional-order multivariable system with parameter uncertainty. The designed FOMRAC scheme depends on a fractional-order nonlinear scalar update la...

(This article belongs to the Special Issue Fractional Calculus and Mathematical Applications)
  • Article
  • Open Access
1 Citations
2,179 Views
16 Pages

30 August 2024

In this paper, we present a novel explicit structure-preserving numerical method for solving nonlinear space-fractional Schrödinger equations based on the concept of the scalar auxiliary variable approach. Firstly, we convert the equations into...

(This article belongs to the Special Issue Fractional Calculus - Theory and Applications II)
  • Article
  • Open Access
6 Citations
3,628 Views
19 Pages

A Spherical Volume-Rendering Method of Ocean Scalar Data Based on Adaptive Ray Casting

  • Weijie Li,
  • Changxia Liang,
  • Fan Yang,
  • Bo Ai and ,
  • Qingtong Shi and
  • Guannan Lv
  • + 1 author+ 0 author

There are some limitations in traditional ocean scalar field visualization methods, such as inaccurate expression and low efficiency in the three-dimensional digital Earth environment. This paper presents a spherical volume-rendering method based on...

  • Article
  • Open Access
12 Citations
3,374 Views
17 Pages

There is no doubt that there is plethora of optimal fourth-order iterative approaches available to estimate the simple zeros of nonlinear functions. We can extend these method/methods for multiple zeros but the main issue is to preserve the same conv...

(This article belongs to the Special Issue Computational Methods in Analysis and Applications 2020)
  • Article
  • Open Access
2 Citations
3,264 Views
24 Pages

11 January 2024

We study the evolution of quantum fluctuations of gravity around an inflationary solution in renormalizable quantum gravity, in which the initial scalar-fluctuation dominance is shown by the background-free nature expressed by a special conformal inv...

(This article belongs to the Section Cosmology)
  • Article
  • Open Access
1 Citations
3,448 Views
17 Pages

20 January 2020

This paper explores new notions of approximate minimality in set optimization using a set approach. We propose characterizations of several approximate minimal elements of families of sets in real linear spaces by means of general functionals, which...

(This article belongs to the Special Issue Applied Functional Analysis and Its Applications)
  • Article
  • Open Access
2 Citations
1,381 Views
22 Pages

This paper presents a high-order structure-preserving difference scheme for the nonlinear space fractional sine-Gordon equation with damping, employing the triangular scalar auxiliary variable approach. The original equation is reformulated into an e...

(This article belongs to the Special Issue Analysis and Numerical Computations of Nonlinear Fractional and Classical Differential Equations)
  • Article
  • Open Access
2 Citations
3,157 Views
19 Pages

In this paper, we construct and analyze a class of high-order and dissipation-preserving schemes for the nonlinear space fractional generalized wave equations by the newly introduced scalar auxiliary variable (SAV) technique. The system is discretize...

(This article belongs to the Special Issue Novel Numerical Solutions of Fractional PDEs)
  • Article
  • Open Access
16 Citations
4,261 Views
15 Pages

New Adaptive High Starting Torque Scalar Control Scheme for Induction Motors Based on Passivity

  • Juan Carlos Travieso-Torres,
  • Miriam Vilaragut-Llanes,
  • Ángel Costa-Montiel,
  • Manuel A. Duarte-Mermoud and ,
  • Norelys Aguila-Camacho,
  • Camilo Contreras-Jara and
  • Alejandro Álvarez-Gracia
  • + 2 authors+ 0 author

10 March 2020

A novel adaptive high starting torque (HST) scalar control scheme (SCS) for induction motors (IM) is proposed in this paper. It uses a new adaptive-passivity-based controller (APBC) proposed herein for a class of nonlinear systems, with linear explic...

(This article belongs to the Special Issue Control Strategies for Power Conversion Systems)
  • Feature Paper
  • Article
  • Open Access
3 Citations
1,014 Views
24 Pages

31 October 2025

A variety of methods that provide approximate piecewise- analytical solutions to initial-value problems governed by scalar, nonlinear, first-order, ordinary differential equations is presented. The methods are based on fixing the independent variable...

(This article belongs to the Section C1: Difference and Differential Equations)
  • Feature Paper
  • Article
  • Open Access
3 Citations
3,466 Views
20 Pages

21 January 2025

Piecewise analytical solutions to scalar, nonlinear, first-order, ordinary differential equations based on the second-order Taylor series expansion of their right-hand sides that result in Riccati’s equations are presented. Closed-form solution...

  • Article
  • Open Access
11 Citations
3,450 Views
19 Pages

19 September 2019

The skills of the Normalized Scalar Product (NSP) strategy, commonly used to estimate the wave field, as well as bathymetry and sea-surface current, from X-band radar images, are investigated with the aim to better understand coastal inundation durin...

(This article belongs to the Special Issue Dynamics of the Coastal Zone)
  • Article
  • Open Access
527 Views
22 Pages

3 July 2026

Natural fibre meshes have emerged as a promising class of sustainable geotechnical reinforcement materials; however, no calibrated and validated directional constitutive model currently exists in the scientific literature for Furcraea macrophylla (fi...

(This article belongs to the Special Issue Advanced Technologies and Applications in Geotechnical Engineering)
  • Article
  • Open Access
3 Citations
4,006 Views
11 Pages

31 January 2019

In this paper, based on Kou’s classical iterative methods with fifth-order of convergence, we propose new interval iterative methods for computing a real root of the nonlinear scalar equations. Some numerical experiments have executed with the...

(This article belongs to the Special Issue Numerical Methods for Solving Nonlinear Equations and Systems: Convergence and Stability)
  • Article
  • Open Access
11 Citations
3,156 Views
12 Pages

1 October 2021

There are a number of publications on relativistic objects dealing either with black holes or naked singularities in the center. Here we show that there exist static spherically symmetric solutions of Einstein equations with a strongly nonlinear scal...

(This article belongs to the Special Issue Particles and Fields in Black Hole Environment)
  • Article
  • Open Access
2 Citations
1,000 Views
14 Pages

19 June 2025

We study the charged black-hole solutions of a 2 + 1 nonlinear electrodynamical theory with a cosmological constant. Considered as a one-parameter group of theories (the exponent of the squared Maxwell tensor), the causal structure of all possible bl...

(This article belongs to the Section Compact Objects)
  • Abstract
  • Open Access
1,705 Views
1 Page

Monopole Solutions in SU(2) Yang–Mills and Nonlinear Spinor Field Theory

  • Serikbolova Albina Askarovna and
  • Dzhunushaliev Vladimir Dzhumakadyrovich

Monopole solutions in SU(2) Yang–Mills theory, which interact with massive nonlinear spinor fields, described by the nonlinear Dirac equation, are obtained. These solutions describe a magnetic monopole created by a spherical lump of nonlinear spinor...

(This article belongs to the Proceedings of The 1st Electronic Conference on Universe)
  • Article
  • Open Access
24 Citations
7,572 Views
39 Pages

Evaluation of Adaptive Loop-Bandwidth Tracking Techniques in GNSS Receivers

  • Iñigo Cortés,
  • Johannes Rossouw van der Merwe,
  • Jari Nurmi,
  • Alexander Rügamer and
  • Wolfgang Felber

12 January 2021

Global navigation satellite system (GNSS) receivers use tracking loops to lock onto GNSS signals. Fixed loop settings limit the tracking performance against noise, receiver dynamics, and the current scenario. Adaptive tracking loops adjust these sett...

(This article belongs to the Special Issue Selected Papers from 10th International Conference on Localization and GNSS 2020 (ICL-GNSS 2020))
  • Article
  • Open Access
4 Citations
2,295 Views
11 Pages

2 September 2019

In this paper, we introduce the new concepts of K-adjustability convexity and strictly K-adjustability convexity which respectively generalize and extend the concepts of K-convexity and strictly K-convexity. We establish some new existence and unique...

(This article belongs to the Special Issue Recent Advances in Fixed Point and Best Proximity Point Problems and Their Applications)
  • Article
  • Open Access
2 Citations
2,078 Views
13 Pages

Nonsingular, Lump-like, Scalar Compact Objects in (2 + 1)-Dimensional Einstein Gravity

  • Roberto V. Maluf,
  • Gerardo Mora-Pérez,
  • Gonzalo J. Olmo and
  • Diego Rubiera-Garcia

11 June 2024

We study the space-time geometry generated by coupling a free scalar field with a noncanonical kinetic term to general relativity in (2+1) dimensions. After identifying a family of scalar Lagrangians that yield exact analytical solutions in static an...

(This article belongs to the Collection Open Questions in Black Hole Physics)
  • Article
  • Open Access
4,693 Views
12 Pages

15 February 2017

We find an azimuthal-angle dependent approximate wave like solution to second order on a warped five-dimensional manifold with a self-gravitating U(1) scalar gauge field (cosmic string) on the brane using the multiple-scale method. The spectrum of th...

(This article belongs to the Special Issue Varying Constants and Fundamental Cosmology)
  • Article
  • Open Access
17 Citations
2,426 Views
18 Pages

13 November 2022

In this article, a scalar nonlinear integro-differential equation of second order and a non-linear system of integro-differential equations with infinite delays are considered. Qualitative properties of solutions called the global asymptotic stabilit...

(This article belongs to the Special Issue Mathematical Modeling with Differential Equations in Biology, Chemistry, Economics, Finance and Physics, Volume 2)
  • Article
  • Open Access
5 Citations
2,130 Views
17 Pages

A nonlocal boundary value problem for a couple of two scalar nonlinear differential equations with several generalized proportional Caputo fractional derivatives and a delay is studied. The exact solution of the scalar nonlinear differential equation...

(This article belongs to the Special Issue Feature Papers in Fractal and Fractional 2022–2023)
  • Article
  • Open Access
10 Citations
3,902 Views
8 Pages

In the recent article Phys. Lett. B 2016, 759, 424–429, a new class of field theories called Nonlinear Field Space Theory was proposed. In this approach, the standard field theories are considered as linear approximations to some more general theorie...

(This article belongs to the Special Issue Varying Constants and Fundamental Cosmology)
  • Article
  • Open Access
2 Citations
3,571 Views
24 Pages

28 January 2022

Motivated by mobile devices that record data at a high frequency, we propose a new methodological framework for analyzing a semi-parametric regression model that allow us to study a nonlinear relationship between a scalar response and multiple functi...

(This article belongs to the Special Issue Big Data Analytics and Information Science for Business and Biomedical Applications II)
  • Article
  • Open Access
11 Citations
3,722 Views
18 Pages

New Conservation Laws and Exact Cosmological Solutions in Brans–Dicke Cosmology with an Extra Scalar Field

  • Antonios Mitsopoulos,
  • Michael Tsamparlis,
  • Genly Leon and
  • Andronikos Paliathanasis

27 July 2021

The derivation of conservation laws and invariant functions is an essential procedure for the investigation of nonlinear dynamical systems. In this study, we consider a two-field cosmological model with scalar fields defined in the Jordan frame. In p...

(This article belongs to the Section C: Physics)
  • Article
  • Open Access
2 Citations
909 Views
10 Pages

24 November 2025

In this work, we discuss the conditions that allow the establishment of an equivalence between f(R,T)=R+λh(T) gravity models and General Relativity (GR) coupled to a modified matter sector. We do so by considering a D-dimensional spacetime and...

(This article belongs to the Special Issue Geometric Theories of Gravity)
  • Article
  • Open Access
11 Citations
2,070 Views
15 Pages

30 December 2022

In this article, a class of scalar nonlinear integro-differential equations of first order with fading memory is investigated. For the considered fading memory problem, we discuss the effects of the memory over all the values of the parameter in the...

(This article belongs to the Special Issue Fractional Differential and Fractional Integro-Differential Equations: Qualitative Theory, Numerical Simulations, and Symmetry Analysis)
  • Article
  • Open Access
774 Views
15 Pages

Hayward Boson Stars

  • Sebastian S. Chicaiza-Medina and
  • Juan Carlos Degollado

We examined the Einstein–Klein–Gordon system coupled to a nonlinear electrodynamics framework that asymptotically supports a Hayward spacetime. We explored the solution space of a static, spherically symmetric, complex scalar field minima...

(This article belongs to the Special Issue Hairy Black Holes: Insights and Advances)
  • Article
  • Open Access
13 Citations
5,159 Views
22 Pages

Dynamically Generated Inflationary ΛCDM

  • David Benisty,
  • Eduardo I. Guendelman,
  • Emil Nissimov and
  • Svetlana Pacheva

20 March 2020

Our primary objective is to construct a plausible, unified model of inflation, dark energy and dark matter from a fundamental Lagrangian action first principle, wherein all fundamental ingredients are systematically dynamically generated starting fro...

(This article belongs to the Special Issue Selected Papers: 10th Mathematical Physics Meeting)
  • Article
  • Open Access
1 Citations
1,982 Views
12 Pages

Unified Convergence Criteria of Derivative-Free Iterative Methods for Solving Nonlinear Equations

  • Samundra Regmi,
  • Ioannis K. Argyros,
  • Stepan Shakhno and
  • Halyna Yarmola

A local and semi-local convergence is developed of a class of iterative methods without derivatives for solving nonlinear Banach space valued operator equations under the classical Lipschitz conditions for first-order divided differences. Special cas...

  • Article
  • Open Access
2 Citations
2,466 Views
10 Pages

2 February 2024

This paper presents new classes of exact radial solutions to the nonlinear ordinary differential equation that arises as a saddle-point condition for a Euclidean scalar field theory in D-dimensional spacetime. These solutions are found by exploiting...

(This article belongs to the Section Field Theory)
  • Article
  • Open Access
11 Citations
3,708 Views
14 Pages

A New Three-Step Class of Iterative Methods for Solving Nonlinear Systems

  • Raudys R. Capdevila,
  • Alicia Cordero and
  • Juan R. Torregrosa

11 December 2019

In this work, a new class of iterative methods for solving nonlinear equations is presented and also its extension for nonlinear systems of equations. This family is developed by using a scalar and matrix weight function procedure, respectively, gett...

(This article belongs to the Special Issue Selected Papers from Iterative Processes for Solving Nonlinear Problems: Convergence and Stability of ICIAM 2019 and MME&HB 2019)
  • Article
  • Open Access
5 Citations
3,865 Views
9 Pages

The Stability of Linear Diffusion Acceleration Relative to CMFD

  • Zackary Dodson,
  • Brendan Kochunas and
  • Edward Larsen

24 September 2021

Coarse Mesh Finite Difference (CMFD) is a widely-used iterative acceleration method for neutron transport problems in which nonlinear terms are introduced in the derivation of the low-order CMFD diffusion equation. These terms, including the homogeni...

(This article belongs to the Special Issue Selected Papers from PHYSOR 2020)
  • Article
  • Open Access
40 Citations
4,894 Views
17 Pages

Bounce Cosmology in Generalized Modified Gravities

  • Georgios Minas,
  • Emmanuel N. Saridakis,
  • Panayiotis C. Stavrinos and
  • Alkiviadis Triantafyllopoulos

We investigate the bounce realization in the framework of generalized modified gravities arising from Finsler and Finsler-like geometries. In particular, a richer intrinsic geometrical structure is reflected in the appearance of extra degrees of free...

(This article belongs to the Special Issue Bounce Cosmology)
  • Article
  • Open Access
1 Citations
1,575 Views
14 Pages

K-Essence Sources of Kerr–Schild Spacetimes

  • Bence Juhász and
  • László Árpád Gergely

17 March 2025

We extend a result by one of the authors, established for nonvacuum Einstein gravity, to minimally coupled k-essence scalar–tensor theories. First, we prove that in order to source a Kerr–Schild-type spacetime, the k-essence Lagrangian sh...

(This article belongs to the Section Gravitation)
  • Article
  • Open Access
3 Citations
9,662 Views
14 Pages

31 March 2017

Terms related to gradients of scalar fields are introduced as scalar products into the formulation of entropy. A Lagrange density is then formulated by adding constraints based on known conservation laws. Applying the Lagrange formalism to the result...

(This article belongs to the Section Astrophysics, Cosmology, and Black Holes)
  • Article
  • Open Access
1,453 Views
11 Pages

22 July 2024

We consider the problem of determining the weights of difference schemes whose form is specified by a particular symbolic expression. The order of approximation of the differential equation is equal to a given number. To solve it, it was propose to p...

(This article belongs to the Section C2: Dynamical Systems)
  • Article
  • Open Access
34 Citations
4,161 Views
12 Pages

In this paper, nonlinear nonautonomous equations with the generalized proportional Caputo fractional derivative (GPFD) are considered. Some stability properties are studied by the help of the Lyapunov functions and their GPFDs. A scalar nonlinear fra...

(This article belongs to the Section General Mathematics, Analysis)
  • Article
  • Open Access
33 Citations
4,202 Views
17 Pages

4 September 2017

Conformal higher spin (CHS) fields, yet being non unitary, provide a remarkable example of a consistent interacting higher spin theory in flat space background, that is local to all orders. The non-linear action is defined as the logarithmically UV d...

(This article belongs to the Special Issue Higher Spin Gauge Theories)
  • Review
  • Open Access
12 Citations
2,873 Views
32 Pages

The non-linear dynamics of scalar fields coupled to matter and gravity can lead to remarkable density-dependent screening effects. In this short review, we present the main classes of screening mechanisms, and discuss their tests in laboratory and as...

(This article belongs to the Special Issue Cosmological Constant)
  • Article
  • Open Access
3 Citations
2,778 Views
13 Pages

A simple-form scalar differential equation with delay and nonlinear negative periodic feedback is considered. The existence of several types of slowly oscillating periodic solutions is shown with the same and double periods of the feedback coefficien...

(This article belongs to the Special Issue Recent Advances and New Challenges in Coupled Systems and Networks: Theory, Modelling, and Applications)
  • Article
  • Open Access
16 Citations
4,245 Views
19 Pages

Multi-Objective Optimization of Gas Pipeline Networks

  • Andrzej J. Osiadacz and
  • Niccolo Isoli

2 October 2020

The main goal of this paper is to prove that bi-objective optimization of high-pressure gas networks ensures grater system efficiency than scalar optimization. The proposed algorithm searches for a trade-off between minimization of the running costs...

(This article belongs to the Special Issue Advanced Techniques and Technologies in Natural Gas Research and Engineering)
  • Article
  • Open Access
27 Citations
3,701 Views
13 Pages

General Slow-Roll Inflation in f(R) Gravity under the Palatini Approach

  • Sabit Bekov,
  • Kairat Myrzakulov,
  • Ratbay Myrzakulov and
  • Diego Sáez-Chillón Gómez

26 November 2020

Slow-roll inflation is analyzed in the context of modified gravity within the Palatini formalism. As shown in the literature, inflation in this framework requires the presence of non-traceless matter; otherwise, it does not occur just as a consequenc...

(This article belongs to the Special Issue Symmetry: Feature Papers 2020)
  • Proceeding Paper
  • Open Access
415 Views
8 Pages

We investigate the harvesting of entanglement in de Sitter spacetime between two identical comoving Unruh–DeWitt detectors. The detectors interact locally with a complex scalar field after they are initially unentangled, creating an effective couplin...

(This article belongs to the Proceedings of The 3rd International Online Conference on Universe)
  • Article
  • Open Access
23 Citations
4,576 Views
18 Pages

Convergence and Stability of a Parametric Class of Iterative Schemes for Solving Nonlinear Systems

  • Alicia Cordero,
  • Eva G. Villalba,
  • Juan R. Torregrosa and
  • Paula Triguero-Navarro

3 January 2021

A new parametric class of iterative schemes for solving nonlinear systems is designed. The third- or fourth-order convergence, depending on the values of the parameter being proven. The analysis of the dynamical behavior of this class in the context...

(This article belongs to the Special Issue Mathematical Methods, Modelling and Applications)
  • Article
  • Open Access
2 Citations
6,048 Views
13 Pages

Exact Solution and Exotic Fluid in Cosmology

  • Seyen Kouwn,
  • Taeyoon Moon and
  • Phillial Oh

20 September 2012

We investigate cosmological consequences of nonlinear sigma model coupled with a cosmological fluid which satisfies the continuity equation. The target space action is of the de Sitter type and is composed of four scalar fields. The potential which i...

(This article belongs to the Special Issue Modified Gravity: From Black Holes Entropy to Current Cosmology)

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