Subjects -> MATHEMATICS (Total: 1013 journals)     - APPLIED MATHEMATICS (92 journals)    - GEOMETRY AND TOPOLOGY (23 journals)    - MATHEMATICS (714 journals)    - MATHEMATICS (GENERAL) (45 journals)    - NUMERICAL ANALYSIS (26 journals)    - PROBABILITIES AND MATH STATISTICS (113 journals) MATHEMATICS (714 journals)                  1 2 3 4 | Last

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 Applied Mathematics - A Journal of Chinese UniversitiesJournal Prestige (SJR): 0.17 Number of Followers: 1      Hybrid journal (It can contain Open Access articles) ISSN (Print) 1993-0445 - ISSN (Online) 1005-1031 Published by Springer-Verlag  [2467 journals]
• Flow of EMHD nanofluid in curved channel through corrugated walls

Abstract: Abstract The present examination deals with the effects of nanofluids on corrugated walls under the influence of electromagnetohydrodynamic (EMHD) in the curved channel. The investigation is carried out by water-based nanofluids using copper nanoparticle. Firstly performed the mathematical modelling by applying the method of perturbation, we have evaluated analytical solutions for the velocity and temperature. For the corrugations of the two walls periodic sine waves are described for small amplitude either in phase or out of phase. By using numerical calculations we analyzed the corrugation effects on the velocity and temperature for EMHD flow. The physical effects of flow variables like Hartmann number, Volumetric concentration of nanoparticles, Grashof number, Curvature parameter and Heat absorption coefficient are graphically discussed. Moreover, the effect of Curvature parameter on Stresses and Nusselt number is discussed through tables. The velocity and temperature decrease when the curvature parameter is increased. The electromagnetohydrodynamic (EMHD) velocity and temperature distributions show that 0° is the phase difference between the two walls for in phase and the phase difference is equal to the 180° between two walls for out of phase. The important conclusion is that reducing the unobvious wave effect on the velocity and temperature for a small value of amplitude ratio parameter.
PubDate: 2022-12-01

• Certain averaging operators on Triebel-Lizorkin spaces

Abstract: Abstract In this article, we study the boundedness properties of the averaging operator S t γ on Triebel-Lizorkin spaces $$\dot F_{p,q}^\alpha \left( {{\mathbb{R}^n}} \right)$$ for various p,q. As an application, we obtain the norm convergence rate for S t γ (f) on Triebel-Lizorkin spaces and the relation between the smoothness imposed on functions and the rate of norm convergence of S t γ is given.
PubDate: 2022-12-01

• Mathematical methods for maintenance and operation cost prediction based
on transfer learning in State Grid

Abstract: Abstract The electric power enterprise is an important basic energy industry for national development, and it is also the first basic industry of the national economy. With the continuous expansion of State Grid, the progressively complex operating conditions, and the increasing scope and frequency of data collection, how to make reasonable use of electrical big data, improve utilization, and provide a theoretical basis for the reliability of State Grid operation, has become a new research hot spot. Since electrical data has the characteristics of large volume, multiple types, low-value density, and fast processing speed, it is a challenge to mine and analyze it deeply, extract valuable information efficiently, and serve for the actual problem. According to the features of these data, this paper uses artificial intelligence methods such as time series and support vector regression to establish a data mining network model for standard cost prediction through transfer learning. The experimental results show that the model in this paper obtains better prediction results on a small sample data set, which verifies the feasibility of the deep transfer model. Compared with activity-based costing and the traditional prediction method, the average absolute error of the proposed method is reduced by 10%, which is effective and superior.
PubDate: 2022-12-01

• Symmetries and conservation laws associated with a hyperbolic mean
curvature flow

Abstract: Abstract Under investigation in this paper is a hyperbolic mean curvature flow for convex evolving curves. Firstly, in view of Lie group analysis, infinitesimal generators, symmetry groups and an optimal system of symmetries of the considered hyperbolic mean curvature flow are presented. At the same time, some group invariant solutions are computed through reduced equations. In particular, we construct explicit solutions by applying the power series method. Furthermore, the convergence of the solutions of power series is certificated. Finally, conservation laws of the hyperbolic mean curvature flow are established via Ibragimov’s approach.
PubDate: 2022-12-01

• Fuzzy rough sets in Šostak sense

Abstract: Abstract In this paper, we defined the fuzzy operator Φλ in a fuzzy ideal approximation space (X, R, $${\cal I}$$ ) associated with a fuzzy rough set λ in Šostak sense. Associated with Φλ, there are fuzzy ideal interior and closure operators int Φ λ and cl Φ λ , respectively. r-fuzzy separation axioms, r-fuzzy connectedness and r-fuzzy compactness in fuzzy ideal approximation spaces are defined and compared with the relative notions in r-fuzzy approximation spaces. There are many differences when studying these notions related with a fuzzy ideal different from studying these notions in usual fuzzy approximation spaces. Lastly, using a fuzzy grill, we will get the same results given during the context.
PubDate: 2022-12-01

• Inverse resonance problems with the discontinuous conditions

Abstract: Abstract In this paper, we consider the inverse resonance problems for the discontinuous and non-selfadjoint Sturm-Liouville problem. We prove the uniqueness theorem and provide a reconstructive algorithm for the potential by using the Cauchy data and Weyl function.
PubDate: 2022-12-01

• Some new fixed point results under constraint inequalities in comparable
complete partially ordered Menger PM-spaces

Abstract: Abstract In this paper, we introduce the concept of comparable $${\cal T}$$ -completeness of a partially ordered Menger PM-space and discuss the existence of fixed points for mappings satisfying certain conditions in the framework of a comparable $${\cal T}$$ -complete partially ordered Menger PM-space. We obtain some new results which generalize many known ones in the literature. Moreover, we derive some consequent results and give an example to illustrate our main result.
PubDate: 2022-12-01

• Fisher information for generalized Rayleigh distribution in ranked set
sampling design with application to parameter estimation

Abstract: Abstract In the current paper, we considered the Fisher information matrix from the generalized Rayleigh distribution (GR) distribution in ranked set sampling (RSS). The numerical results show that the ranked set sample carries more information about λ and α than a simple random sample of equivalent size. In order to give more insight into the performance of RSS with respect to (w.r.t.) simple random sampling (SRS), a modified unbiased estimator and a modified best linear unbiased estimator (BLUE) of scale and shape λ and α from GR distribution in SRS and RSS are studied. The numerical results show that the modified unbiased estimator and the modified BLUE of λ and α in RSS are significantly more efficient than the ones in SRS.
PubDate: 2022-12-01

• Application of Bernstein polynomials for solving Fredholm
integro-differential-difference equations

Abstract: Abstract In this paper, the Bernstein polynomials method is proposed for the numerical solution of Fredholm integro-differential-difference equation with variable coefficients and mixed conditions. This method is using a simple computational manner to obtain a quite acceptable approximate solution. The main characteristic behind this method lies in the fact that, on the one hand, the problem will be reduced to a system of algebraic equations. On the other hand, the efficiency and accuracy of the Bernstein polynomials method for solving these equations are high. The existence and uniqueness of the solution have been proved. Moreover, an estimation of the error bound for this method will be shown by preparing some theorems. Finally, some numerical experiments are presented to show the excellent behavior and high accuracy of this algorithm in comparison with some other well-known methods.
PubDate: 2022-12-01

• Inverting a k-heptadiagonal matrix based on Doolitle LU factorization

Abstract: Abstract The purpose of the present paper is to show a new numeric and symbolic algorithm for inverting a general nonsingular k-heptadiagonal matrix. This work is based on Doolitle LU factorization of the matrix. We obtain a series of recursive relationships then we use them for constructing a novel algorithm for inverting a k-heptadiagonal matrix. The computational cost of the algorithm is calculated. Some illustrative examples are given to demonstrate the effectiveness of the proposed method.
PubDate: 2022-09-01
DOI: 10.1007/s11766-022-3763-8

• Poisson Distribution Results for ϑ-Spirallike Functions of Order
γ

Abstract: Abstract The main objective of this organized paper is to establish the Poisson distribution conditions for the ϑ-spirallike function classes Sϑ(γ; ψ) and Kϑ(γ; ψ). We also investigate an integral operator associated with the Poisson distribution.
PubDate: 2022-09-01
DOI: 10.1007/s11766-022-4253-8

• A generalized Liouville’s formula

Abstract: Abstract A generalized Liouville’s formula is established for linear matrix differential equations involving left and right multiplications. Its special cases are used to determine the localness of characteristics of symmetries and solutions to Riemann-Hilbert problems in soltion theory.
PubDate: 2022-09-01
DOI: 10.1007/s11766-022-3572-0

• MHD stagnation point flow of nanofluid with SWCNT and MWCNT over a
stretching surface driven by Arrhenius kinetics

Abstract: Abstract The intention of the current research is to address the conclusion of non-isothermal heterogeneous reaction on the stagnation — point flow of SWCNT — engine oil and MWCNT — engine oil nanofluid over a shrinking/stretching sheet. Further, exemplify the aspect of heat and mass transfer the upshot of magnetohydrodynamics (MHD), thermal radiation, and heat generation/absorption coefficient are exemplified. The bvp4c from Matlab is pledged to acquire the numerical explanation of the problem that contains nonlinear system of ordinary differential equations (ODE). The impacts of miscellaneous important parameters on axial velocity, temperature field, concentration profile, skin friction coefficient, and local Nusselt number, are deliberated through graphical and numerically erected tabulated values. The solid volume fraction diminishes the velocity distribution while enhancing the temperature distribution. Further, the rate of shear stress declines with increasing the magnetic and stretching parameter for both SWCNT and MWCNT.
PubDate: 2022-09-01
DOI: 10.1007/s11766-022-3966-z

• Bootstrap inference of the skew-normal two-way classification random
effects model with interaction

Abstract: Abstract In this paper, we consider the statistical inference problems for the fixed effect and variance component functions in the two-way classification random effects model with skew-normal errors. Firstly, the exact test statistic for the fixed effect is constructed. Secondly, using the Bootstrap approach and generalized approach, the one-sided hypothesis testing and interval estimation problems for the single variance component, the sum and ratio of variance components are discussed respectively. Further, the Monte Carlo simulation results indicate that the exact test statistic performs well in the one-sided hypothesis testing problem for the fixed effect. And the Bootstrap approach is better than the generalized approach in the one-sided hypothesis testing problems for variance component functions in most cases. Finally, the above approaches are applied to the real data examples of the consumer price index and value-added index of three industries to verify their rationality and effectiveness.
PubDate: 2022-09-01
DOI: 10.1007/s11766-022-4320-1

• Modified integral equation combined with the decomposition method for time
fractional differential equations with variable coefficients

Abstract: Abstract In this paper, the modified integral equation, namely, Elzaki transformation coupled with the Adomian decomposition method called Elzaki Adomian decomposition method (EADM) is used to investigate the solution of time-fractional fourth-order parabolic partial differential equations (PDEs) with variable coefficients. The introduced method is used to solve two models of the proposed problem, the analytical and approximate solutions of the models are obtained. The outcomes illustrate that the proposed technique is a highly accurate, and facilitates the process of solving differential equations by comparing it, with the exact solution and those obtained by the variation iteration method (VIM) and Laplace homotopy perturbation method (LHPM).
PubDate: 2022-09-01
DOI: 10.1007/s11766-022-4159-5

• Semi entropy of uncertain random variables and its application to
portfolio selection

Abstract: Abstract Semi entropy is a measure to characterize the indeterminacy of the uncertain random variable considering the values of the uncertain random variable which are lower than the mean. As important roles of semi entropy in finance, this paper presents the concept of semi entropy for uncertain random variables. In order to compute semi entropy for uncertain random variables, Monte-Carlo approach is provided. As an application of semi entropy, portfolio selection problems are optimized based on mean-semi entropy mode.
PubDate: 2022-09-01
DOI: 10.1007/s11766-022-4106-5

• On the grouping effect of the l1−2 models

Abstract: Abstract This paper aims to study the mathematical properties of the l1−2 models that employ measurement matrices with correlated columns. We first show that the l1−2 model satisfies the grouping effect which ensures that coefficients corresponding to highly correlated columns in a measurement matrix have small differences. Then we provide the stability analysis based on the sparse approximation property. When the entries of the vectors have different signs, we show that the grouping effect also holds for the constraint l1+2 minimization model which is implicated by the linearized Bregman iteration.
PubDate: 2022-09-01
DOI: 10.1007/s11766-022-4256-5

• Asymptotic analysis of a nonlinear stochastic eco-epidemiological system
with feedback control

Abstract: Abstract This paper proposes a new stochastic eco-epidemiological model with nonlinear incidence rate and feedback controls. First, we prove that the stochastic system has a unique global positive solution. Second, by constructing a series of appropriate stochastic Lyapunov functions, the asymptotic behaviors around the equilibria of deterministic model are obtained, and we demonstrate that the stochastic system exists a stationary Markov process. Third, the conditions for persistence in the mean and extinction of the stochastic system are established. Finally, we carry out some numerical simulations with respect to different stochastic parameters to verify our analytical results. The obtained results indicate that the stochastic perturbations and feedback controls have crucial effects on the survivability of system.
PubDate: 2022-09-01
DOI: 10.1007/s11766-022-3631-6

• Enhanced optimal delaunay triangulation methods with connectivity
regularization

Abstract: Abstract In this paper, we study the underlying properties of optimal Delaunay triangulations (ODT) and propose enhanced ODT methods combined with connectivity regularization. Based on optimizing node positions and Delaunay triangulation iteratively, ODT methods are very effective in mesh improvement. This paper demonstrates that the energy function minimized by ODT is nonconvex and unsmooth, thus, ODT methods suffer the problem of falling into a local minimum inevitably. Unlike general ways that minimize the ODT energy function in terms of mathematics directly, we take an outflanking strategy combining ODT methods with connectivity regularization for this issue. Connectivity regularization reduces the number of irregular nodes by basic topological operations, which can be regarded as a perturbation to help ODT methods jump out of a poor local minimum. Although the enhanced ODT methods cannot guarantee to obtain a global minimum, it starts a new viewpoint of minimizing ODT energy which uses topological operations but mathematical methods. And in terms of practical effect, several experimental results illustrate the enhanced ODT methods are capable of improving the mesh furtherly compared to general ODT methods.
PubDate: 2022-09-01
DOI: 10.1007/s11766-022-4588-1

• Traveling wave for a time-periodic Lotka-Volterra model with bistable
nonlinearity

Abstract: Abstract This paper studies bistable wavefronts of a diffusive time-periodic Lotka-Volterra system. We obtain a new condition for the existence, uniqueness and stability of bistable time-periodic traveling waves. This condition is sharp and greatly improves the result established in the reference (X. Bao and Z. Wang, Journal of Differential Equations, 255(2013) 2402–2435). An example is given to demonstrate our consequence.
PubDate: 2022-09-01
DOI: 10.1007/s11766-022-4139-9

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