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Mathematics, Volume 10, Issue 8

2022 April-2 - 150 articles

Cover Story:

Lepage forms represent a far-going generalization of a 1-form, introduced by E. Cartan in the 1920s within the framework of the calculus of variations of simple integrals and classical mechanics. The generalization, offered by D. Krupka, is motivated by the work of Th. Lepage in the 1940s. These objects define the same variational functional as it is prescribed by a given Lagrangian, and moreover, variational objects (as variations, extremals, or Noether’s type invariance) are globally characterized in terms of geometric operations acting on the Lepage equivalents of a Lagrangian.

Here, a second-order extension of the fundamental Lepage form of the calculus of variations over fibered manifolds with 2-dimensional base is described via order-reducibility of the generalized Poincaré–Cartan form. View this paper

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Articles (150)

  • Article
  • Open Access
9 Citations
3,823 Views
22 Pages

Artificial Neural Based Speed and Flux Estimators for Induction Machine Drives with Matlab/Simulink

  • Ahmed A. Zaki Diab,
  • Mohammed A. Elsawy,
  • Kotin A. Denis,
  • Salem Alkhalaf and
  • Ziad M. Ali

18 April 2022

In this paper, an Artificial Neural Network (ANN) for accurate estimation of the speed and flux for induction motor (IM) drives has been presented for industrial applications such as electric vehicles (EVs). Two ANN estimators have been designed, one...

  • Article
  • Open Access
1 Citations
2,382 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...

  • Article
  • Open Access
22 Citations
3,391 Views
26 Pages

18 April 2022

Due to the disturbance effect of excavation, the original stress is redistributed, resulting in an excavation damaged zone around the roadway. It is significant to predict the thickness of an excavation damaged zone because it directly affects the st...

  • Article
  • Open Access
2 Citations
1,722 Views
14 Pages

18 April 2022

The purpose of this paper is to present a numerical method for solving a generalized equilibrium problem involving a Lipschitz continuous and monotone mapping in a Hilbert space. The proposed method can be viewed as an improvement of the Tseng’...

  • Article
  • Open Access
1 Citations
2,288 Views
13 Pages

18 April 2022

Structural conditions and population characteristics of countries have been identified in the literature as factors for an individual to become, or to have intentions of becoming, an entrepreneur. However, this is still a subject under research, whic...

  • Article
  • Open Access
21 Citations
2,961 Views
31 Pages

MHD Natural Convection and Radiation over a Flame in a Partially Heated Semicircular Cavity Filled with a Nanofluid

  • Obai Younis,
  • Milad Alizadeh,
  • Ahmed Kadhim Hussein,
  • Bagh Ali,
  • Uddhaba Biswal and
  • Emad Hasani Malekshah

18 April 2022

The numerical analysis of MHD-free convective heat transfer and its interaction with the radiation over a heated flame inside a porous semicircular cavity loaded with SWCNTs–water nanofluid was explored for the very first time in the present wo...

  • Article
  • Open Access
16 Citations
3,156 Views
17 Pages

18 April 2022

Owing to the complex dynamics of quadrotor unmanned aerial vehicles (UAVs) and their susceptibility to unknown interferences in an actual working environment, the flight control accuracy of UAVs is extremely high. Moreover, their anti-interference ab...

  • Article
  • Open Access
15 Citations
2,877 Views
13 Pages

18 April 2022

Grouting is one of the main technical means to prevent water inrush hazards in coal seam floor aquifers. It is of great significance to elucidate the diffusion law of slurry in the process of grouting in fractured aquifers for safe mining in coal min...

  • Article
  • Open Access
8 Citations
2,949 Views
16 Pages

Contextual Semantic-Guided Entity-Centric GCN for Relation Extraction

  • Jun Long,
  • Lei Liu,
  • Hongxiao Fei,
  • Yiping Xiang,
  • Haoran Li,
  • Wenti Huang and
  • Liu Yang

18 April 2022

Relation extraction tasks aim to predict potential relations between entities in a target sentence. As entity mentions have ambiguity in sentences, some important contextual information can guide the semantic representation of entity mentions to impr...

  • Article
  • Open Access
7 Citations
2,559 Views
19 Pages

The Generalization of the Brusov–Filatova–Orekhova Theory for the Case of Payments of Tax on Profit with Arbitrary Frequency

  • Peter Brusov,
  • Tatiana Filatova,
  • Natali Orekhova,
  • Veniamin Kulik,
  • She-I Chang and
  • George Lin

18 April 2022

Both main theories of capital cost and capital structure—the Brusov–Filatova–Orekhova (BFO) theory and its perpetuity limit, the Modigliani–Miller theory—consider the payments of tax on profit once per year, while in real economy these payments are m...

  • Article
  • Open Access
8 Citations
3,834 Views
25 Pages

18 April 2022

Multi-degree-of-freedom isolator with low stiffness is a fair prospect in engineering application. In this paper, a novel 6-DOF QZS vibration isolation platform based on leaf spring structure is presented. Its bearing capacity is provided through fou...

  • Article
  • Open Access
2 Citations
2,497 Views
13 Pages

Meanings Expressed by Primary Schoolchildren When Solving a Partitioning Task

  • Elena Castro-Rodríguez,
  • Marisel Ferreira,
  • Ana B. Montoro and
  • Juan F. Ruiz-Hidalgo

18 April 2022

This study entailed an in-depth exploration of the meanings identified by a group of 105 fourth year primary schoolchildren when solving a task involving partitioning. The research was based on a semantic triangle consisting of a conceptual structure...

  • Article
  • Open Access
9 Citations
2,875 Views
20 Pages

18 April 2022

With the vigorous development of the mobile Internet, online social networks have greatly changed the way of life of human beings. As an important branch of online social network research, influence maximization refers to finding K nodes in the netwo...

  • Article
  • Open Access
5 Citations
2,961 Views
16 Pages

18 April 2022

The development of probabilistic thinking at school requires enhancing combinatorial and proportional reasoning. For this reason, 190 sixth-grade elementary school students (11–12-year-old), without previous instruction in the topic, solve a ta...

  • Article
  • Open Access
7 Citations
2,822 Views
17 Pages

18 April 2022

The present paper was inspired by recent developments in laboratory experiments within the framework of cancer-on-chip technology, an immune-oncology microfluidic chip aiming at studying the fundamental mechanisms of immunocompetent behavior. We focu...

  • Article
  • Open Access
10 Citations
3,257 Views
20 Pages

Bistability and Chaos Emergence in Spontaneous Dynamics of Astrocytic Calcium Concentration

  • Evgeniya V. Pankratova,
  • Maria S. Sinitsina,
  • Susanna Gordleeva and
  • Victor B. Kazantsev

18 April 2022

In this work, we consider a mathematical model describing spontaneous calcium signaling in astrocytes. Based on biologically relevant principles, this model simulates experimentally observed calcium oscillations and can predict the emergence of compl...

  • Article
  • Open Access
15 Citations
2,148 Views
15 Pages

Gradient and Parameter Dependent Dirichlet (p(x),q(x))-Laplace Type Problem

  • Kholoud Saad Albalawi,
  • Nadiyah Hussain Alharthi and
  • Francesca Vetro

18 April 2022

We analyze a Dirichlet (p(x),μq(x))-Laplace problem. For a gradient dependent nonlinearity of Carathéodory type, we discuss the existence, uniqueness and asymptotic behavior of weak solutions, as the parameter μ varies on the non-negativ...

  • Article
  • Open Access
3 Citations
5,775 Views
12 Pages

Dense-to-Question and Sparse-to-Answer: Hybrid Retriever System for Industrial Frequently Asked Questions

  • Jaehyung Seo,
  • Taemin Lee,
  • Hyeonseok Moon,
  • Chanjun Park,
  • Sugyeong Eo,
  • Imatitikua D. Aiyanyo,
  • Kinam Park,
  • Aram So,
  • Sungmin Ahn and
  • Jeongbae Park

18 April 2022

The term “Frequently asked questions” (FAQ) refers to a query that is asked repeatedly and produces a manually constructed response. It is one of the most important factors influencing customer repurchase and brand loyalty; thus, most ind...

  • Article
  • Open Access
5 Citations
3,372 Views
16 Pages

Robust Detection and Modeling of the Major Temporal Arcade in Retinal Fundus Images

  • Dora Elisa Alvarado-Carrillo,
  • Iván Cruz-Aceves,
  • Martha Alicia Hernández-González and
  • Luis Miguel López-Montero

18 April 2022

The Major Temporal Arcade (MTA) is a critical component of the retinal structure that facilitates clinical diagnosis and monitoring of various ocular pathologies. Although recent works have addressed the quantitative analysis of the MTA through param...

  • Article
  • Open Access
19 Citations
3,881 Views
21 Pages

A Novel Dynamic Mathematical Model Applied in Hash Function Based on DNA Algorithm and Chaotic Maps

  • Nada E. El-Meligy,
  • Tamer O. Diab,
  • Ashraf S. Mohra,
  • Ashraf Y. Hassan and
  • Wageda I. El-Sobky

17 April 2022

This paper aims to improve SHA-512 security without increasing complexity; therefore, we focused on hash functions depending on DNA sequences and chaotic maps. After analysis of 45 various chaotic map types, only 5 types are selected in this proposal...

  • Article
  • Open Access
15 Citations
2,473 Views
17 Pages

Fractional Evolution Equations with Infinite Time Delay in Abstract Phase Space

  • Ahmed Salem,
  • Kholoud N. Alharbi and
  • Hashim M. Alshehri

17 April 2022

In the presented research, the uniqueness and existence of a mild solution for a fractional system of semilinear evolution equations with infinite delay and an infinitesimal generator operator are demonstrated. The generalized Liouville–Caputo...

  • Article
  • Open Access
12 Citations
3,109 Views
14 Pages

Synthesized Landing Strategy for Quadcopter to Land Precisely on a Vertically Moving Apron

  • Nguyen Xuan Mung,
  • Ngoc Phi Nguyen,
  • Dinh Ba Pham,
  • Nhu Ngoc Dao and
  • Sung Kyung Hong

17 April 2022

Quadcopter unmanned aerial vehicles have become increasingly popular for various real-world applications, and a significant body of literature exists regarding the improvement of their flight capabilities to render them fully autonomous. The precise...

  • Article
  • Open Access
3 Citations
2,771 Views
23 Pages

Investigation of 2D Seismic DDA Method for Numerical Simulation of Shaking Table Test of Rock Mass Engineering

  • Xiaodong Fu,
  • Jingyu Kang,
  • Qian Sheng,
  • Lu Zheng,
  • Wenjie Du and
  • Haifeng Ding

17 April 2022

Since the basic theory of the discontinue deformation analysis (DDA) method was proposed, the DDA open source has gone through a long development process. At present, different kinds of programs have been widely applied in rock mass engineering such...

  • Article
  • Open Access
3 Citations
2,433 Views
23 Pages

17 April 2022

The differential quadrature method (DQM) is a numerical technique widely applied in structure mechanics problems. In this work, a top-tensioned riser conveying fluid is considered. The governing equation of this riser under parametric excitations is...

  • Article
  • Open Access
39 Citations
8,135 Views
23 Pages

A Comparative Study of Forecasting Electricity Consumption Using Machine Learning Models

  • Madeline Hui Li Lee,
  • Yee Chee Ser,
  • Ganeshsree Selvachandran,
  • Pham Huy Thong,
  • Le Cuong,
  • Le Hoang Son,
  • Nguyen Trung Tuan and
  • Vassilis C. Gerogiannis

17 April 2022

Production of electricity from the burning of fossil fuels has caused an increase in the emission of greenhouse gases. In the long run, greenhouse gases cause harm to the environment. To reduce these gases, it is important to accurately forecast elec...

  • Article
  • Open Access
1 Citations
1,983 Views
10 Pages

Algebraic Systems with Positive Coefficients and Positive Solutions

  • Ana Maria Acu,
  • Ioan Raşa and
  • Ancuţa Emilia Şteopoaie

16 April 2022

The paper is devoted to the existence, uniqueness and nonuniqueness of positive solutions to nonlinear algebraic systems of equations with positive coefficients. Such systems appear in large numbers of applications, such as steady-state equations in...

  • Article
  • Open Access
29 Citations
2,786 Views
25 Pages

15 April 2022

In this paper, a transmission expansion planning (TEP) model is proposed to guarantee the resilience of power systems and mitigate cascading failures’ impacts. The energy storage systems and fault current limiters’ planning models are int...

  • Article
  • Open Access
5 Citations
2,609 Views
16 Pages

15 April 2022

Periodical fluctuation is a common phenomenon in food safety supervision. The existing literature on China’s food safety supervision mainly analyzes periodical fluctuation by statistical methods. This paper provides a theoretical explanation by...

  • Article
  • Open Access
2 Citations
3,225 Views
14 Pages

15 April 2022

This paper presents results from a study about problem solving related to the concept of the greatest common divisor with secondary school students. The perspective of the analysis is the meaningful learning of the constructivist theory. The main obj...

  • Article
  • Open Access
3 Citations
2,372 Views
17 Pages

15 April 2022

In this paper, a localized boundary knot method is adopted to solve two-dimensional inverse Cauchy problems, which are controlled by a second-order linear differential equation. The localized boundary knot method is a numerical method based on the lo...

  • Article
  • Open Access
23 Citations
6,241 Views
23 Pages

15 April 2022

The publication opportunities in science require knowing the existing gaps in the academic debate. In recent decades, scholars specializing in fuzzy theory and applied methodologies have experienced an unprecedented evolution of the field. The Sustai...

  • Article
  • Open Access
34 Citations
2,938 Views
37 Pages

Bending and Buckling of FG-GRNC Laminated Plates via Quasi-3D Nonlocal Strain Gradient Theory

  • Emad E. Ghandourah,
  • Ahmed A. Daikh,
  • Abdulsalam M. Alhawsawi,
  • Othman A. Fallatah and
  • Mohamed A. Eltaher

15 April 2022

To improve the structural stiffness, strength and reduce the weight of nanoplate structure, functionally graded (FG) graphene-reinforced nanocomposite (GRNC) laminated plates are exploited in this paper. The bending and buckling behaviors of FG-GRNC...

  • Article
  • Open Access
3 Citations
3,032 Views
20 Pages

15 April 2022

Graph representation learning is a significant challenge in graph signal processing (GSP). The flourishing development of graph neural networks (GNNs) provides effective representations for GSP. To effectively learn from graph signals, we propose a r...

  • Article
  • Open Access
8 Citations
2,516 Views
24 Pages

Numerical Method for a Filtration Model Involving a Nonlinear Partial Integro-Differential Equation

  • Dossan Baigereyev,
  • Dinara Omariyeva,
  • Nurlan Temirbekov,
  • Yerlan Yergaliyev and
  • Kulzhamila Boranbek

15 April 2022

In this paper, we propose an efficient numerical method for solving an initial boundary value problem for a coupled system of equations consisting of a nonlinear parabolic partial integro-differential equation and an elliptic equation with a nonlinea...

  • Article
  • Open Access
5 Citations
2,596 Views
17 Pages

Feature Reconstruction from Incomplete Tomographic Data without Detour

  • Simon Göppel,
  • Jürgen Frikel and
  • Markus Haltmeier

15 April 2022

In this paper, we consider the problem of feature reconstruction from incomplete X-ray CT data. Such incomplete data problems occur when the number of measured X-rays is restricted either due to limit radiation exposure or due to practical constraint...

  • Article
  • Open Access
2 Citations
1,771 Views
23 Pages

Non-Normal Market Losses and Spatial Dependence Using Uncertainty Indices

  • Catalina Bolancé,
  • Carlos Alberto Acuña and
  • Salvador Torra

15 April 2022

We analyse spatial dependence between the risks of stock markets. An alternative definition of neighbour is used and is based on a proposed exogenous criterion obtained with a dynamic Google Trends Uncertainty Index (GTUI) designed specifically for t...

  • Article
  • Open Access
2 Citations
3,251 Views
17 Pages

15 April 2022

We propose a new goodness-of-fit test for the Rayleigh distribution which is based on a distributional fixed-point property of the Stein characterization. The limiting null distribution of the test is derived and the consistency against fixed alterna...

  • Article
  • Open Access
1,621 Views
18 Pages

Categorification of Integer Sequences via Brauer Configuration Algebras and the Four Subspace Problem

  • Agustín Moreno Cañadas,
  • Pedro Fernando Fernández Espinosa and
  • Natalia Agudelo Muñetón

15 April 2022

The four subspace problem is a known matrix problem, which is equivalent to determining all the indecomposable representations of a poset consisting of four incomparable points. In this paper, we use solutions of this problem and invariants associate...

  • Article
  • Open Access
3 Citations
3,414 Views
34 Pages

Stress State in an Eccentric Elastic Ring Loaded Symmetrically by Concentrated Forces

  • Stelian Alaci,
  • Florina-Carmen Ciornei and
  • Ionut-Cristian Romanu

14 April 2022

The stress state from an eccentric ring made of an elastic material symmetrically loaded on the outer boundary by concentrated forces is deduced. The analytical results are obtained using the Airy stress function expressed in bipolar coordinates. The...

  • Article
  • Open Access
3 Citations
2,239 Views
17 Pages

14 April 2022

Interregional collaboration is a core element of Chinese innovation policy, as it accelerates the knowledge recombination across geographic boundaries and promotes regional R&D performance. This study emphasizes interregional collaboration and in...

  • Article
  • Open Access
1,673 Views
15 Pages

14 April 2022

This paper mainly studies several control problems of a complex 4D chaotic system. Firstly, the real part and imaginary part of the complex 4D chaotic system are separated, and the system is equivalent to a six-dimensional continuous autonomous real...

  • Article
  • Open Access
24 Citations
4,987 Views
25 Pages

Guided Hybrid Modified Simulated Annealing Algorithm for Solving Constrained Global Optimization Problems

  • Khalid Abdulaziz Alnowibet,
  • Salem Mahdi,
  • Mahmoud El-Alem,
  • Mohamed Abdelawwad and
  • Ali Wagdy Mohamed

14 April 2022

In this paper, a hybrid gradient simulated annealing algorithm is guided to solve the constrained optimization problem. In trying to solve constrained optimization problems using deterministic, stochastic optimization methods or hybridization between...

  • Article
  • Open Access
62 Citations
7,459 Views
30 Pages

An Improved Wild Horse Optimizer for Solving Optimization Problems

  • Rong Zheng,
  • Abdelazim G. Hussien,
  • He-Ming Jia,
  • Laith Abualigah,
  • Shuang Wang and
  • Di Wu

14 April 2022

Wild horse optimizer (WHO) is a recently proposed metaheuristic algorithm that simulates the social behavior of wild horses in nature. Although WHO shows competitive performance compared to some algorithms, it suffers from low exploitation capability...

  • Article
  • Open Access
14 Citations
2,330 Views
9 Pages

14 April 2022

In the present paper, making use of Gegenbauer polynomials, we initiate and explore a new family JΣ(λ,γ,s,t,q;h) of holomorphic and bi-univalent functions which were defined in the unit disk D associated with the q-Srivastava&ndash...

  • Article
  • Open Access
66 Citations
11,660 Views
21 Pages

14 April 2022

Cryptocurrencies can be considered as mathematical money. As the most famous cryptocurrency, the Bitcoin price forecasting model is one of the popular mathematical models in financial technology because of its large price fluctuations and complexity....

  • Article
  • Open Access
6 Citations
2,588 Views
22 Pages

14 April 2022

To study the mining stress evolution law of inclined backfilled stope in deep mining, this paper first proposes a method for determining the parameters of the brittle-ductile transition model corresponding to the Hoek–Brown criterion and Mohr-C...

  • Article
  • Open Access
9 Citations
2,663 Views
19 Pages

Bayesian Influence Analysis of the Skew-Normal Spatial Autoregression Models

  • Yuanyuan Ju,
  • Yan Yang,
  • Mingxing Hu,
  • Lin Dai and
  • Liucang Wu

14 April 2022

In spatial data analysis, outliers or influential observations have a considerable influence on statistical inference. This paper develops Bayesian influence analysis, including the local influence approach and case influence measures in skew-normal...

  • Article
  • Open Access
4 Citations
2,097 Views
25 Pages

14 April 2022

In a previous work by the same authors, a hollow annular membrane structure loaded transversely and uniformly was proposed, and its closed-form solution was presented; its anticipated use is for designing elastic shells of revolution. Since the heigh...

  • Article
  • Open Access
9 Citations
1,891 Views
19 Pages

On Coupled Best Proximity Points in Reflexive Banach Spaces

  • Laura Ajeti,
  • Atanas Ilchev and
  • Boyan Zlatanov

14 April 2022

We investigated the existence and uniqueness of coupled best proximity points for some cyclic and semi-cyclic maps in a reflexive Banach space. We found sufficient conditions, ensuring the existence of coupled best proximity points in reflexive Banac...

  • Article
  • Open Access
7 Citations
2,641 Views
27 Pages

14 April 2022

Brain storm optimization algorithm (BSO) is a popular swarm intelligence algorithm. A significant part of BSO is to divide the population into different clusters with the clustering strategy, and the blind disturbance operator is used to generate off...

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Mathematics - ISSN 2227-7390