Volume 24, Issue 4

In this paper, we study 3D object reconstruction based on a set of 2D images. In order to get the best camera path that increases accuracy we focus on this strategy to be used. Euclidean 3D image-based reconstruction is developed in three steps, which are primitive extraction, correspondence of these primitives and then triangulation. The extraction and triangulation are purely geometrical, whereas the matching step can have precision issues especially in the case of noisy images. An experimental study is carried out where a camera is attached to a robot arm and moved precisely relative to a scene containing a checkerboard calibration pattern. The reconstruction results are compared with values of motion given to the robot. A geometric and analytical study of the impact of the motion of the camera with respect to the scene on the error of a 3D image-based reconstructed point was also carried out. It has been demonstrated that the impact of a correspondence error on the reconstruction accuracy point varies drastically depending on the image capture strategy.

This article studies a six-bit digital phase shifter and its compatible design through different physiognomies. Furthermore, the communication circuits are applied based on modern knowledge by application. The study started with the initial values of 5.625° as the digital phase shifter is programmed discrete and advanced to a 64-step size. Moreover, the properties of bandwidth are computed by 6.44–10.85 GHz. (C-X band) is related to the phase shifter around the frequency, so the full improvement of 66 dB of the phase shifter is 7 dB. Besides, the phase is changing in array antenna and secondhand in optimal Design. Finally, the study discusses dissimilar kinds of digital phase shifters, to study the parameters that affects the design in future cases.

In this work, the dynamical behaviors of the Jimbo–Miwa equation that describes certain interesting (3 + 1)-dimensional waves in physics but does not pass any of the conventional integrability tests are studied. One-, two-, and three-M-lump waves are constructed successfully. Interactions between one-M-lump and one-soliton wave, between one-M-lump and two-soliton wave as well as between two-M-lump and one-soliton solution are reported. Also, complex multi-soliton, solutions are offered. The simplified Hirota’s method and a long-wave method are used to construct these types of solutions. The velocity of a one-M-lump wave is studied. Straight Lines of travel for M-lump waves are also reported. To our knowledge, all gained solutions in this research paper are novel and not reported beforehand. Moreover, the gained solutions are presented graphically in three dimensions to better understand the physical phenomena of the suggested equation.

The optimal control, for a class of nonlinear neutral evolution equations involving Riemann–Liouville fractional derivative, is investigated in this paper by using Darbo–Sadovskii fixed point theorem. An example is given in the last section to illustrate the validity of the abstract conclusions.

In order to understand consumers’ perceptual cognition of Zhangpu paper-cut patterns and grasp the innovative application direction. The four design elements of paper-cut patterns were extracted by morphological analysis, and representative perceptual vocabulary were selected using Kansei engineering theory and factor analysis, then the design elements and perceptual evaluation scores of representative words are used as the input and output data of the GWO-BP neural network, respectively, to establish an intelligent model that can predict consumers’ perceptual cognition of paper-cut patterns. To verify the superiority of the model, the predicted result of BP and FA-BP are compared with GWO-BP neural network. The results show that although the convergence speed of the GWO-BP model is slightly lower than that of the FA-BP model, its prediction accuracy is significantly better than other algorithms. Designers can use the model to quickly redesign the paper-cut pattern to better meet the aesthetic needs of modern consumers.

In this article, we present a study of two iterative schemes to approximate the fixed points of enriched non-expansive maps and enriched generalized non-expansive maps. The schemes introduced in this article generalize those given by Thakur et al. in (“A new iterative scheme for approximating fixed points of nonexpansive mappings,” Filomat , vol. 30, no. 10, pp. 2711–2720, 2016.) and Ali et al. in (“Approximation of Fixed points for Suzuki’s generalized nonexpansive mappings,” Mathematics , vol. 7, no. 6, pp. 522–532, 2019.) in a sense that our schemes work for larger classes of enriched mappings and the schemes given by Thakur et al. and Ali et al. reduce to a particular case of our iterative techniques. Taking inspiration from Berinde (“Picard iteration converges faster than Mann iteration for a class of quasi-contractive operators,” Fixed Point Theory Appl. , vol. 2004, no. 2, pp. 97–105, 2004.) and Maniu (“On a three-step iteration process for Suzuki mappings with qualitative study,” Numer. Funct. Anal. Optim. , 2020.), we also give stability results of the our procedures for enriched contractions (introduced by Berinde in 2019). Lastly, we compare the rate of convergence of our schemes with each other and the conventional Krasnoselskii iteration process used for approximating fixed points of enriched contractions along with some examples. As an application to the proposed iterative schemes, we give a few results on the solutions of linear system of equations.

In this paper, by applying Pachpatte’s type integral inequality with integral impulses, we investigate Ulam–Hyers and Ulam–Hyers–Rassias stabilities for the impulsive Volterra delay integrodifferential equation Banach spaces. Suitable examples are given to support the obtained results.

In many life time scenarios, life of one component or system nested in other components or systems. To model these complex structures some so called nested models are required rather than conventional models. This paper introduces the generalization of the method of generating continuous distribution proposed by N. Eugene, C. Lee, and F. Famoye, “Beta-normal distribution and its applications,” Commun. Stat. Theor. Methods , vol. 31, no. 4, pp. 497–512, 2002 and A. Alzaatreh, C. Lee, and F. Famoye, “A new method for generating families of continuous distributions,” Metron , vol. 71, no. 1, pp. 63–79, 2013 which nest one model in other to cope with complex systems. Some important characteristics of the proposed family of generalized distribution have been studied. The famous Beta, Kumaraswami and Gamma generated distributions are special cases of our suggested procedure. Some new distributions have also been developed by using the suggested methodology and their important properties have been discussed as well. A variety of real life data sets are used to demonstrate the efficacy of new suggested distributions and illation is made with baseline models.

This study investigates the functional abstract second order impulsive differential equation with state-dependent delay. The major result of this study is that the abstract second-order impulsive differential equation with state-dependent delay system has at least one solution and is unique. After that, the wellposed condition is defined. Following that, we look at whether the proposed problem is wellposed. Finally, some illustrations of our findings are provided.

The present article investigates the effects of heat and mass transfer on the pulsatile flow of blood through a tapered artery under atherosclerotic conditions. The blood is treated as Sutterby fluid. The wall of the artery is considered to be time-invariant having overlapping stenosis in its lumen. The fully coupled momentum, energy and concentration equations in conjunction with the constitutive equation of Sutterby fluid are simplified by applying the mild stenosis assumption. The governing equations together with the prescribed boundary conditions are discretized and solved by using the finite difference method. The results highlighting the effects of various emerging parameters on the heat and mass transfer are also displayed through graphs. The effects of stenosis height and Prandtl number on the axial variation of Nusselt number are also discussed in detail. A comparison of Sutterby fluid with the Newtonian fluid is also presented to highlight the effects of the Prandtl number on the heat and mass transfer. The present study reveals that the distribution of temperature in the constricted region of the blood vessel is closely associated with the viscoelastic nature of blood. It is also observed that the rate of heat transfer at the wall of the artery can be enhanced by reducing the thermal conductivity.

It is always a difficult task to study the dynamic fracture of prefabricated cracks under stress wave loading. To investigate loadings of stress waves on dynamic cracks, a crack propagation testing configuration consisting of a one-point bend specimen loaded in split Hopkinson pressure bar (SHPB) was used, which loaded an unconstrained polymethyl methacrylate (PMMA) plate (120 mm × 60 mm × 5 mm) on the edge opposite to the cracked edge. A modified simple pre-cracked specimen geometry under impact stress wave loading to generate pure mode I crack at crack initiation was demonstrated, which can avoid the superposition and interference of various waves to facilitate the research. The numerical simulation was performed firstly by ABAQUS to prove the existence of the mode I field at the crack tip leading to crack propagation and indicate the stress distribution and evolution in the specimen caused by the propagation of the impact stress wave, analyze the propagation characteristics of the wave. Then dynamic caustics method in conjunction with high-speed photography was utilized in SHPB impact experiment. The propagation of shock stress wave in the specimen and its interaction with the prefabricated crack and the stress concentration at the tip of the prefabricated crack were analyzed. The corresponding stress intensity factor history is precisely determined. Finally, it is concluded that the observed distortion phenomenon at the impact point belongs to a caustic behavior under compression load, which reflects the stress concentration at the impact point. And the mode I failure occurs along the pre-crack direction. Specifically, the pre-crack shows obvious pure mode I crack propagation characteristics under symmetrical reflected tensile wave, the stress at the crack tip changes from compressive stress to tensile stress. And crack propagates under tensile stress wave reflected from its two free boundaries without crack, while the compressive stress wave can not make crack initiate and has little influence on crack propagation. Which agree with the numerical prediction.

Three-dimensional investigation has been carried out to simulate buoyancy induced heat transfer and fluid flow as well as entropy creation inside C-shaped enclosure charged with based water CNT–Al 2 O 3 (15–85%) hybrid nanofluid. Left side is isothermally heated while the vertical portions of the right wall are isothermally cooled. Effects of various parameters on the flow behavior and the produced irreversibilities, namely the cavity aspect ratio (0.1 ≤ Ar ≤ 0.4), Rayleigh number (10 3 ≤ Ra ≤ 10 6 ) and volumetric fraction of hybrid nanofluid (0 ≤ φ ≤ 0.06) have been examined. It was revealed that the aspect ratio is the main controlling parameter of thermal energy transfer and generated entropy. In addition, for specific Ra, adding hybrid nanoparticles leads to the increase of the average Nusselt number while the highest produced entropy is observed with higher Rayleigh number. Moreover, the maximum Bejan number occurred for a shape factor Ar = 0.1 and Ra = 10 4 disregarding the hybrid nanoparticles volume fraction showing the dominance of thermal irreversibility over the viscous dissipation irreversibility in such conditions.

This paper is dedicated to investigating the existence of solutions to the initial value problem (IVP) for a coupled system of Ψ-Hilfer hybrid fractional differential equations (FDEs) and boundary value problem (BVP) for a coupled system of Ψ-Hilfer hybrid FDEs. Analysis of the current paper depends on the two fixed point theorems involving three operators characterized on Banach algebra. In the view of an application, we provided useful examples to exhibit the effectiveness of our achieved results.

Aiming at the problem of the specified stress condition in a partial region of the structure, the Hellinger–Reissner (H–R) variational principle is studied to provide a theoretical basis for the finite element numerical analysis. By introducing the unknown non-elastic strain as an additional unknown quantity to fulfill the specified stress condition, the elastic mechanics governing equations for the specified stress problem are given. Both stress and unknown non-elastic strain are taken as independent variables to establish the complementary energy principle and virtual work equation which are equivalent to the elastic mechanical control equation of the specified stress problem. Based on the conventional H–R variational principle, using displacement, stress and unknown non-elastic strain as independent variables, a H–R variational functional that satisfies the specified stress conditions is established by using Lagrange multiplier method. Also the variational functional with displacement, elastic strain and unknown non-elastic strain as independent variables is deduced by transforming the stress into the elastic strain. The corresponding finite formulae are derived based on an intra-element stress hybridization method. The H–R variational principle for the specified stress problem takes non-elastic strain as an independent variable, so that the stress explicitly appears in the equilibrium equation of the element and structure, which expands the application range and capabilities of the existing variational principle and finite element method. The correctness and accuracy of the theory and algorithm are verified by numerical examples.

The present article explores the effect of viscous dissipation on steady natural convection Couette flow subject to convective boundary condition. Due to the nonlinearity and coupling of the governing equations in the present situation, the homotopy perturbation method was employed to obtain the solutions of the energy and momentum equations. The impacts of the controlling parameters were investigated and discussed graphically. In the course of investigation, it was found that fluid temperature increases with an increase in viscous dissipation while the reverse trend was observed in fluid velocity. However, it was also discovered that heat generation leads to a decrease in the rate of heat transfer on the heated plate and it increases on the cold plate. Finally, it was concluded that the velocity boundary layer thickness increases with an increase in Biot number.

The general Fredholm determinants have a close connection with integrable systems. Inspired by the connection between Fredholm determinants and mKdV/sinh-Gordon hierarchies, we construct a Z n -Fredholm determinant and show how the Z n -Fredholm determinants can be governed by Z n -mKdV/ Z n -sinh-Gordon hierarchies.

In this paper, the exact analytical solutions to the generalized Schrödinger equation are investigated. The Schrodinger type equations bearing nonlinearity are the important models that flourished with the wide-ranging arena concerning plasma physics, nonlinear optics, fluid-flow, and the theory of deep-water waves, etc. In this exploration, the soliton and other traveling wave solutions in an appropriate form to the generalized nonlinear Schrodinger equation by means of the extended sinh-Gordon equation expansion method, tan(Γ( ϖ ))-expansion method, and the improved cos(Γ( ϖ )) function method are obtained. The suggested model of the nonlinear Schrodinger equation is turned into a differential ordinary equation of a single variable through executing some operations. One soliton, periodic, and singular wave solutions to this important equation in physics are reached. The periodic solutions are expressed in terms of the rational functions. Soliton solutions are obtained from them as a particular case. The obtained solutions are figured out in the profiles of 2D, density, and 3D plots by assigning suitable values of the involved unknown constants. Modulation instability (MI) is employed to discuss the stability of got solutions. These various graphical appearances enable the researchers to understand the underlying mechanisms of intricate phenomena of the leading equation. The individual performances of the employed methods are praiseworthy which deserves further application to unravel any other nonlinear partial differential equations (NLPDEs) arising in various branches of sciences. The proposed methodologies for resolving NLPDEs have been designed to be effectual, unpretentious, expedient, and manageable.

This paper designs a modified weighted essentially non-oscillatory (WENO) scheme for solving hyperbolic conservation laws. Using the switching principle based on inflection points, the new scheme automatically adapts between linear upwind and WENO schemes. If there is at least one inflection point in the largest stencil available for reconstruction, a symmetrical WENO (SWENO) scheme is considered for the reconstruction of the numerical flux; otherwise the numerical flux is directly approximated by the reconstruction polynomial. By comparing the new scheme introduced in this paper with the classical WENO scheme and another improved scheme that has been proposed recently D. Chai, G. Xi, Z. Sun, Z. Wangand Z. Huang, Comput. Fluids , vol. 170, pp. 176–186, 2018), we can point out the robustness and better efficiency of this scheme. To examine and explain the features of the new scheme, a number of examples such as Euler equations have been considered.

The main objective of this paper is to provide an efficient image encryption for each and every single person in order to secure their own records while saving them in social networks. We have formulated the delayed fuzzy cellular neural networks (FCNNs) with suitable keys that are the values of the parameters of FCNNs and obtain the irregular dynamical signal (solution) which encrypts the images. We have utilized entirely 42 parameters as a key sensitivity in the order of 10 −15 among them three elements of initial condition parameters are sensitive to the order of 10 −14 . Lastly, comparison results are provided with the existing literature. The measurements show that the proposed algorithm is a novel overall solution for image encryption.

The current study focuses on the thermal stability of exothermic MHD reactive squeezed fluid flow between parallel plates. The problem’s governing nonlinear partial differential equations are transformed into dimensionless ones. The dimensionless equations obtained are highly nonlinear and are then numerically solved using the spectral collocation method (SCM). The acquired results are verified using Runge–Kutta fourth-fifth order (RK45) combined with shooting method, and a good agreement is achieved. Some graphs and tables are provided to examine the exothermic combustion process by focusing on the effects of emergent kinetic parameters such as activation energy, heat generation, and squeezed flow on the temperature profile and thermal stability of the system. It is discovered that the activation energy parameter tends to minimize the temperature profile while also improving the system’s thermal stability. However, the squeezed parameter and the heat generation rate parameter increase exothermic chemical reactions, causing the system to become unstable.

In this paper, we consider two-step fourth-order and three-step sixth-order derivative free iterative methods and study their convergence in Banach spaces to approximate a locally-unique solution of nonlinear equations. Study of convergence analysis provides radius of convergence, error bounds and estimates on the uniqueness of the solution. Such estimates are not provided in the approaches that use Taylor expansions using higher order derivatives. Furthermore, in quest of fast algorithms, a generalized q -step scheme with increasing convergence order 2 q + 2 is proposed and analyzed. Novelty of the q -step algorithm is that, in each step, order of convergence is increased by an amount of two at the cost of only one additional function evaluation. To maximize the computational efficiency, the optimal number of steps is calculated. Theoretical results regarding convergence and computational efficiency are verified through numerical experimentation.