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Keywords = antiderivative

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51 pages, 554 KB  
Article
Mean-Field-Type Transformers
by Hamidou Tembine, Manzoor Ahmed Khan and Issa Bamia
Mathematics 2024, 12(22), 3506; https://doi.org/10.3390/math12223506 - 9 Nov 2024
Cited by 1 | Viewed by 3798
Abstract
In this article, we present the mathematical foundations of generative machine intelligence and link them with mean-field-type game theory. The key interaction mechanism is self-attention, which exhibits aggregative properties similar to those found in mean-field-type game theory. It is not necessary to have [...] Read more.
In this article, we present the mathematical foundations of generative machine intelligence and link them with mean-field-type game theory. The key interaction mechanism is self-attention, which exhibits aggregative properties similar to those found in mean-field-type game theory. It is not necessary to have an infinite number of neural units to handle mean-field-type terms. For instance, the variance reduction in error within generative machine intelligence is a mean-field-type problem and does not involve an infinite number of decision-makers. Based on this insight, we construct mean-field-type transformers that operate on data that are not necessarily identically distributed and evolve over several layers using mean-field-type transition kernels. We demonstrate that the outcomes of these mean-field-type transformers correspond exactly to the mean-field-type equilibria of a hierarchical mean-field-type game. Due to the non-convexity of the operators’ composition, gradient-based methods alone are insufficient. To distinguish a global minimum from other extrema—such as local minima, local maxima, global maxima, and saddle points—alternative methods that exploit hidden convexities of anti-derivatives of activation functions are required. We also discuss the integration of blockchain technologies into machine intelligence, facilitating an incentive design loop for all contributors and enabling blockchain token economics for each system participant. This feature is especially relevant to ensuring the integrity of factual data, legislative information, medical records, and scientifically published references that should remain immutable after the application of generative machine intelligence. Full article
(This article belongs to the Section E1: Mathematics and Computer Science)
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22 pages, 780 KB  
Article
Numerical Integration of Highly Oscillatory Functions with and without Stationary Points
by Konstantin P. Lovetskiy, Leonid A. Sevastianov, Michal Hnatič and Dmitry S. Kulyabov
Mathematics 2024, 12(2), 307; https://doi.org/10.3390/math12020307 - 17 Jan 2024
Cited by 4 | Viewed by 4251
Abstract
This paper proposes an original approach to calculating integrals of rapidly oscillating functions, based on Levin’s algorithm, which reduces the search for an anti-derivative function to solve an ODE with a complex coefficient. The direct solution of the differential equation is based on [...] Read more.
This paper proposes an original approach to calculating integrals of rapidly oscillating functions, based on Levin’s algorithm, which reduces the search for an anti-derivative function to solve an ODE with a complex coefficient. The direct solution of the differential equation is based on the method of integrating factors. The reduction in the original integration problem to a two-stage method for solving ODEs made it possible to overcome the instability that arises in the standard (in the form of solving a system of linear algebraic equations) approach to the solution. And due to the active use of Chebyshev interpolation when using the collocation method on Gauss–Lobatto grids, it is possible to achieve high speed and stability when taking into account a large number of collocation points. The presented spectral method of integrating factors is both flexible and reliable and allows for avoiding the ambiguities that arise when applying the classical method of collocation for the ODE solution (Levin) in the physical space. The new method can serve as a basis for solving ordinary differential equations of the first and second orders when creating high-efficiency software, which is demonstrated by solving several model problems. Full article
(This article belongs to the Section E: Applied Mathematics)
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13 pages, 787 KB  
Article
Specific Features of Polynomials in Several Examples
by Stan Lipovetsky
Axioms 2024, 13(1), 43; https://doi.org/10.3390/axioms13010043 - 11 Jan 2024
Cited by 4 | Viewed by 3004
Abstract
This paper considers polynomial characteristics useful for a better understanding of the behaviour of these functions. Taylor series for the polynomials are described by the items with even and odd derivatives and powered changes in the argument, which leads to more specific studying [...] Read more.
This paper considers polynomial characteristics useful for a better understanding of the behaviour of these functions. Taylor series for the polynomials are described by the items with even and odd derivatives and powered changes in the argument, which leads to more specific studying of their properties. Connections between the derivative and antiderivative of the polynomial functions are defined. The structure of polynomial functions reveals their specific characteristic that the mean value of their roots equals the mean value of the locations of the critical points such as the extrema and inflection points. Derivatives of the quadratic exponent in relation to an interesting connection of two transcendental numbers are also described. The discussed properties of the polynomials can be helpful for practical implementations and educational purposes. Full article
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16 pages, 309 KB  
Article
Euler–Lagrange-Type Equations for Functionals Involving Fractional Operators and Antiderivatives
by Ricardo Almeida
Mathematics 2023, 11(14), 3208; https://doi.org/10.3390/math11143208 - 21 Jul 2023
Cited by 2 | Viewed by 2045
Abstract
The goal of this paper is to present the necessary and sufficient conditions that every extremizer of a given class of functionals, defined on the set C1[a,b], must satisfy. The Lagrange function depends on a generalized [...] Read more.
The goal of this paper is to present the necessary and sufficient conditions that every extremizer of a given class of functionals, defined on the set C1[a,b], must satisfy. The Lagrange function depends on a generalized fractional derivative, on a generalized fractional integral, and on an antiderivative involving the previous fractional operators. We begin by obtaining the fractional Euler–Lagrange equation, which is a necessary condition to optimize a given functional. By imposing convexity conditions over the Lagrange function, we prove that it is also a sufficient condition for optimization. After this, we consider variational problems with additional constraints on the set of admissible functions, such as the isoperimetric and the holonomic problems. We end by considering a generalization of the fundamental problem, where the fractional order is not restricted to real values between 0 and 1, but may take any positive real value. We also present some examples to illustrate our results. Full article
(This article belongs to the Special Issue Recent Research on Fractional Calculus: Theory and Applications)
20 pages, 1016 KB  
Article
Minimum Superstability of Stochastic Ternary Antiderivations in Symmetric Matrix-Valued FB-Algebras and Symmetric Matrix-Valued FC-⋄-Algebras
by Zahra Eidinejad, Reza Saadati, Donal O’Regan and Fehaid Salem Alshammari
Symmetry 2022, 14(10), 2064; https://doi.org/10.3390/sym14102064 - 3 Oct 2022
Cited by 3 | Viewed by 1606
Abstract
Our main goal in this paper is to investigate stochastic ternary antiderivatives (STAD). First, we will introduce the random ternary antiderivative operator. Then, by introducing the aggregation function using special functions such as the Mittag-Leffler function (MLF), the Wright function (WF), the H [...] Read more.
Our main goal in this paper is to investigate stochastic ternary antiderivatives (STAD). First, we will introduce the random ternary antiderivative operator. Then, by introducing the aggregation function using special functions such as the Mittag-Leffler function (MLF), the Wright function (WF), the H-Fox function (HFF), the Gauss hypergeometric function (GHF), and the exponential function (EXP-F), we will select the optimal control function by performing the necessary calculations. Next, by considering the symmetric matrix-valued FB-algebra (SMV-FB-A) and the symmetric matrix-valued FC-⋄-algebra (SMV-FC-⋄-A), we check the superstability of the desired operator. After stating each result, the superstability of the minimum is obtained by applying the optimal control function. Full article
(This article belongs to the Special Issue Elementary Fixed Point Theory and Common Fixed Points)
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11 pages, 281 KB  
Article
Fractional Line Integral
by Gabriel Bengochea and Manuel Ortigueira
Mathematics 2021, 9(10), 1150; https://doi.org/10.3390/math9101150 - 20 May 2021
Viewed by 2707
Abstract
This paper proposed a definition of the fractional line integral, generalising the concept of the fractional definite integral. The proposal replicated the properties of the classic definite integral, namely the fundamental theorem of integral calculus. It was based on the concept of the [...] Read more.
This paper proposed a definition of the fractional line integral, generalising the concept of the fractional definite integral. The proposal replicated the properties of the classic definite integral, namely the fundamental theorem of integral calculus. It was based on the concept of the fractional anti-derivative used to generalise the Barrow formula. To define the fractional line integral, the Grünwald–Letnikov and Liouville directional derivatives were introduced and their properties described. The integral was defined for a piecewise linear path first and, from it, for any regular curve. Full article
(This article belongs to the Special Issue Fractional Calculus and Nonlinear Systems)
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20 pages, 9201 KB  
Article
An Experimental Approach on Beating in Vibration Due to Rotational Unbalance
by Dragos-Florin Chitariu, Florin Negoescu, Mihaita Horodinca, Catalin-Gabriel Dumitras, Gures Dogan and Mehmet Ilhan
Appl. Sci. 2020, 10(19), 6899; https://doi.org/10.3390/app10196899 - 1 Oct 2020
Cited by 5 | Viewed by 5508
Abstract
This paper proposes a study in theoretical and experimental terms focused on the vibration beating phenomenon produced in particular circumstances: the addition of vibrations generated by two rotating unbalanced shafts placed inside a lathe headstock, with a flat friction belt transmission between the [...] Read more.
This paper proposes a study in theoretical and experimental terms focused on the vibration beating phenomenon produced in particular circumstances: the addition of vibrations generated by two rotating unbalanced shafts placed inside a lathe headstock, with a flat friction belt transmission between the shafts. The study was done on a simple computer-assisted experimental setup for absolute vibration velocity signal acquisition, signal processing and simulation. The input signal is generated by a horizontal geophone as the sensor, placed on a headstock. By numerical integration (using an original antiderivative calculus and signal correction method) a vibration velocity signal was converted into a vibration displacement signal. In this way, an absolute velocity vibration sensor was transformed into an absolute displacement vibration sensor. An important accomplishment in the evolution of the resultant vibration frequency (or combination frequency as well) of the beating vibration displacement signal was revealed by numerical simulation, which was fully confirmed by experiments. In opposition to some previously reported research results, it was discovered that the combination frequency is slightly variable (tens of millihertz variation over the full frequency range) and it has a periodic pattern. This pattern has negative or positive peaks (depending on the relationship of amplitudes and frequencies of vibrations involved in the beating) placed systematically in the nodes of the beating phenomena. Some other achievements on issues involved in the beating phenomenon description were also accomplished. A study on a simulated signal proves the high theoretical accuracy of the method used for combination frequency measurement, with less than 3 microhertz full frequency range error. Furthermore, a study on the experimental determination of the dynamic amplification factor of the combination vibration (5.824) due to the resonant behaviour of the headstock and lathe on its foundation was performed, based on computer-aided analysis (curve fitting) of the free damped response. These achievements ensure a better approach on vibration beating phenomenon and dynamic balancing conditions and requirements. Full article
(This article belongs to the Special Issue New Materials and Advanced Procedures of Obtaining and Processing)
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13 pages, 554 KB  
Article
Antiderivative Antialiasing for Stateful Systems
by Martin Holters
Appl. Sci. 2020, 10(1), 20; https://doi.org/10.3390/app10010020 - 18 Dec 2019
Cited by 15 | Viewed by 3802
Abstract
Nonlinear systems, such as guitar distortion effects, play an important role in musical signal processing. One major problem encountered in digital nonlinear systems is aliasing distortion. Consequently, various aliasing reduction methods have been proposed in the literature. One of these is based on [...] Read more.
Nonlinear systems, such as guitar distortion effects, play an important role in musical signal processing. One major problem encountered in digital nonlinear systems is aliasing distortion. Consequently, various aliasing reduction methods have been proposed in the literature. One of these is based on using the antiderivative of the nonlinearity and has proven effective, but is limited to memoryless systems. In this work, it is extended to a class of stateful systems which includes but is not limited to systems with a single one-port nonlinearity. Two examples from the realm of virtual analog modeling show its applicability to and effectiveness for commonly encountered guitar distortion effect circuits. Full article
(This article belongs to the Special Issue Digital Audio Effects)
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12 pages, 247 KB  
Article
Analytical Solution of Linear Fractional Systems with Variable Coefficients Involving Riemann–Liouville and Caputo Derivatives
by Ivan Matychyn
Symmetry 2019, 11(11), 1366; https://doi.org/10.3390/sym11111366 - 4 Nov 2019
Cited by 26 | Viewed by 3193
Abstract
This paper deals with the initial value problem for linear systems of fractional differential equations (FDEs) with variable coefficients involving Riemann–Liouville and Caputo derivatives. Some basic properties of fractional derivatives and antiderivatives, including their non-symmetry w.r.t. each other, are discussed. The technique of [...] Read more.
This paper deals with the initial value problem for linear systems of fractional differential equations (FDEs) with variable coefficients involving Riemann–Liouville and Caputo derivatives. Some basic properties of fractional derivatives and antiderivatives, including their non-symmetry w.r.t. each other, are discussed. The technique of the generalized Peano–Baker series is used to obtain the state-transition matrix. Explicit solutions are derived both in the homogeneous and inhomogeneous case. The theoretical results are supported by examples. Full article
(This article belongs to the Special Issue Ordinary and Partial Differential Equations: Theory and Application)
40 pages, 3241 KB  
Article
Dual Taylor Series, Spline Based Function and Integral Approximation and Applications
by Roy M. Howard
Math. Comput. Appl. 2019, 24(2), 35; https://doi.org/10.3390/mca24020035 - 1 Apr 2019
Cited by 6 | Viewed by 4929
Abstract
In this paper, function approximation is utilized to establish functional series approximations to integrals. The starting point is the definition of a dual Taylor series, which is a natural extension of a Taylor series, and spline based series approximation. It is shown that [...] Read more.
In this paper, function approximation is utilized to establish functional series approximations to integrals. The starting point is the definition of a dual Taylor series, which is a natural extension of a Taylor series, and spline based series approximation. It is shown that a spline based series approximation to an integral yields, in general, a higher accuracy for a set order of approximation than a dual Taylor series, a Taylor series and an antiderivative series. A spline based series for an integral has many applications and indicative examples are detailed. These include a series for the exponential function, which coincides with a Padé series, new series for the logarithm function as well as new series for integral defined functions such as the Fresnel Sine integral function. It is shown that these series are more accurate and have larger regions of convergence than corresponding Taylor series. The spline based series for an integral can be used to define algorithms for highly accurate approximations for the logarithm function, the exponential function, rational numbers to a fractional power and the inverse sine, inverse cosine and inverse tangent functions. These algorithms are used to establish highly accurate approximations for π and Catalan’s constant. The use of sub-intervals allows the region of convergence for an integral approximation to be extended. Full article
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14 pages, 358 KB  
Article
Fractional Derivatives: The Perspective of System Theory
by Manuel Duarte Ortigueira and José Tenreiro Machado
Mathematics 2019, 7(2), 150; https://doi.org/10.3390/math7020150 - 5 Feb 2019
Cited by 55 | Viewed by 5442
Abstract
This paper addresses the present day problem of multiple proposals for operators under the umbrella of “fractional derivatives”. Several papers demonstrated that various of those “novel” definitions are incorrect. Here the classical system theory is applied to develop a unified framework to clarify [...] Read more.
This paper addresses the present day problem of multiple proposals for operators under the umbrella of “fractional derivatives”. Several papers demonstrated that various of those “novel” definitions are incorrect. Here the classical system theory is applied to develop a unified framework to clarify this important topic in Fractional Calculus. Full article
(This article belongs to the Special Issue Fractional Integrals and Derivatives: “True” versus “False”)
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23 pages, 11615 KB  
Article
Virtual Analog Models of the Lockhart and Serge Wavefolders
by Fabián Esqueda, Henri Pöntynen, Julian D. Parker and Stefan Bilbao
Appl. Sci. 2017, 7(12), 1328; https://doi.org/10.3390/app7121328 - 20 Dec 2017
Cited by 25 | Viewed by 11535
Abstract
Wavefolders are a particular class of nonlinear waveshaping circuits, and a staple of the “West Coast” tradition of analog sound synthesis. In this paper, we present analyses of two popular wavefolding circuits—the Lockhart and Serge wavefolders—and show that they achieve a very similar [...] Read more.
Wavefolders are a particular class of nonlinear waveshaping circuits, and a staple of the “West Coast” tradition of analog sound synthesis. In this paper, we present analyses of two popular wavefolding circuits—the Lockhart and Serge wavefolders—and show that they achieve a very similar audio effect. We digitally model the input–output relationship of both circuits using the Lambert-W function, and examine their time- and frequency-domain behavior. To ameliorate the issue of aliasing distortion introduced by the nonlinear nature of wavefolding, we propose the use of the first-order antiderivative method. This method allows us to implement the proposed digital models in real-time without having to resort to high oversampling factors. The practical synthesis usage of both circuits is discussed by considering the case of multiple wavefolder stages arranged in series. Full article
(This article belongs to the Special Issue Sound and Music Computing)
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18 pages, 327 KB  
Article
Univariate Cubic L1 Interpolating Splines: Spline Functional, Window Size and Analysis-based Algorithm
by Lu Yu, Qingwei Jin, John E. Lavery and Shu-Cherng Fang
Algorithms 2010, 3(3), 311-328; https://doi.org/10.3390/a3030311 - 20 Aug 2010
Cited by 12 | Viewed by 9101
Abstract
We compare univariate L1 interpolating splines calculated on 5-point windows, on 7-point windows and on global data sets using four different spline functionals, namely, ones based on the second derivative, the first derivative, the function value and the antiderivative. Computational results indicate that [...] Read more.
We compare univariate L1 interpolating splines calculated on 5-point windows, on 7-point windows and on global data sets using four different spline functionals, namely, ones based on the second derivative, the first derivative, the function value and the antiderivative. Computational results indicate that second-derivative-based 5-point-window L1 splines preserve shape as well as or better than the other types of L1 splines. To calculate second-derivative-based 5-point-window L1 splines, we introduce an analysis-based, parallelizable algorithm. This algorithm is orders of magnitude faster than the previously widely used primal affine algorithm. Full article
(This article belongs to the Special Issue Algorithms for Applied Mathematics)
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