136 results on '"Integral equation"'
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2. Reduced-order models for array structures mounted on platforms with parameters variations.
- Author
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Fu, Kunpeng, Shao, Hanru, Li, Minhua, and Hu, Jun
- Subjects
- *
REDUCED-order models , *DOMAIN decomposition methods - Abstract
A hybrid model order reduction (MOR) method is developed to calculate the electromagnetic characteristic of array structures mounted on platforms with parameters variations. The reduced-order model (ROM) of the platform is generated as a reduced-order input-output matrix during the offline stage. Using the equivalence principle algorithm (EPA), the ROM of array is generated by transferring the unknowns on the elements to equivalence surfaces. The frequency and material independent reactions (FMIR) method is applied to support the sweep of array material parameters. In the online stage, when the array positions vary in the input region, both of the array and platform ROMs can be used repeatedly. When the array materials vary in the input region, the platform ROM and geometry dependent matrices of EPA are reusable. Therefore, the computational cost can be reduced significantly. Comparing the proposed method to commercial solver, two numerical results are given to show the efficiency. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Exact solution of Eshelby's inhomogeneity problem in strain gradient theory of elasticity and its applications in composite materials.
- Author
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Bonfoh, Napo and Sabar, Hafid
- Subjects
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STRAINS & stresses (Mechanics) , *ELASTICITY , *COMPOSITE materials , *INTEGRAL equations , *INTEGRAL functions , *GREEN'S functions , *ASYMPTOTIC homogenization - Abstract
• Exact solution of the problem of Eshelby's inhomogeneity in strain gradient elasticity theory. • Green's function technique and integral equation developed for arbitrary boundary conditions. • Analytical expressions of mean strain inside inclusion. • Analytical expressions of effective elastic properties with strain gradient. • Effect of the scale parameter, the contrast of elastic behavior and the volume fraction of inhomogeneity. A new micromechanical approach to deal with the problem of Eshelby's inhomogeneity is developed for the prediction of the effective properties of composite materials according to the strain gradient elasticity theory. The method is based on the Green's function technique leading to an integral equation of the heterogeneous elastic problem. Within the simplified strain gradient elasticity theory, the integral equation for an infinite heterogeneous medium subjected to non-homogeneous boundary conditions is acquired. Thanks to this integral equation, the exact solution of Eshelby's inhomogeneity problem is detailed for spherical inhomogeneity and isotropic elastic behavior. From the expression of strain localization relations, the effective elastic properties of a two-phase composite material are then predicted through Mori Tanaka's homogenization scheme. To test the relevance of the suggested approach, its predictions are compared with results issued from some reference models and experimental data. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. An equivalent formulation of Sonine condition.
- Author
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Zheng, Xiangcheng
- Subjects
- *
VOLTERRA equations , *DIFFERENTIAL equations , *INTEGRAL equations , *FRACTIONAL differential equations - Abstract
Sonine kernel is characterized by the Sonine condition (denoted by SC) and is an important class of kernels in nonlocal differential equations and integral equations. This work proposes a SC with a more general form (denoted by gSC), which is more convenient than SC to accommodate complex kernels and equations. A typical kernel is given, and the first-kind Volterra integral equation under gSC is accordingly transformed and then analyzed. Based on these results, it is finally proved that the gSC is indeed equivalent to the original SC, which indicates that the Sonine kernel may be essentially characterized by the behavior of its convolution with the associated kernel at the starting point. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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5. Generalization of Darbo-type theorem and application on existence of implicit fractional integral equations in tempered sequence spaces.
- Author
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Das, Anupam, Mohiuddine, S.A., Alotaibi, Abdullah, and Deuri, Bhuban Chandra
- Subjects
SEQUENCE spaces ,FRACTIONAL integrals ,EXISTENCE theorems ,GENERALIZATION ,CONTINUOUS functions ,QUADRATIC equations - Abstract
The aim of this work is to give some fixed point results based on the technique of measure of noncompactness which extend the classical Darbo's theorem. With the help of our Darbo-type theorem, we obtain the existence of solution of implicit fractional integral equations in C (I , ℓ p α) (collection of all continuous functions from I = [ 0 , a ] (a > 0) to ℓ p α ), where ℓ p α is a tempered sequence space. Finally, we present a numerical example to see the validity and practicability of our existence result. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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6. On timeline of enhancing testing-capacity of COVID-19: A case study via an optimal replacement model.
- Author
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Meththananda, R.G.U.I., Ganegoda, N.C., Perera, S.S.N., Erandi, K.K.W.H., Jayathunga, Y., and Peiris, H.O.W.
- Subjects
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COVID-19 pandemic , *NONLINEAR integral equations , *COVID-19 , *PARAMETER estimation , *WORK structure , *PRODUCTION planning - Abstract
Process of enhancing testing-capacity regarding COVID-19 is a topic of interest. This task of enhancing is constrained by socio-economic background of a country either in favorable or unfavorable ways. In this paper, we investigate timing of enhancing testing-capacity as an optimal problem, where the enhancement is quantified via number of tests as an instant measure and recovered portion as a long-term measure. The proposed work is structured analogous to an optimal machine replacement model based on a non-linear integral equation. Overall model is partially identifiable and compatible parameter estimations are carried out for a specific case study covering an early stage scenario. In addition, scenario development criteria on demand and effort for enhancing testing-capacity are introduced for predictions. In one numerical experiment, it is observed that frequency of enhancing testing-capacity starts decreasing after two increments indicating a favorable direction amidst effort constraints. • Enhancing testing-capacity of COVID-19 is a process that needs monitoring. • Timing for enhanced testing can be modeled as an optimal replacement model. • Parameter estimation under different scenarios paves the way for process planning. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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7. A new general integral transform for solving integral equations.
- Author
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Jafari, Hossein
- Subjects
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INTEGRAL equations , *INTEGRAL transforms , *ALGEBRAIC equations , *DIFFERENTIAL equations , *INITIAL value problems , *FRACTIONAL differential equations , *LAPLACE transformation - Abstract
[Display omitted] • A new general integral transform which is covered all class of integral transform in the class of Laplace transform. • We investigated the application of this new transform for solving ODE with constant and variable coefficient. • This new transform can handle easily for fractional order integral equations and fractional order differential equations. • We have discussed the advantage and disadvantage of other integral transformed which is defined during last 2 decades. • We proved the related theorems for this new transform. Integral transforms are important to solve real problems. Appropriate choice of integral transforms helps to convert differential equations as well as integral equations into terms of an algebraic equation that can be solved easily. During last two decades many integral transforms in the class of Laplace transform are introduced such as Sumudu, Elzaki, Natural, Aboodh, Pourreza, Mohand, G_transform, Sawi and Kamal transforms. In this paper, we introduce a general integral transform in the class of Laplace transform. We study the properties of this transform. Then we compare it with few exiting integral transforms in the Laplace family such as Laplace, Sumudu, Elzaki and G\_transforms, Pourreza, Aboodh and etc. A new integral transform is introduced. Then some properties of this integral transform are discussed. This integral transform is used to solve this new transform is used for solving higher order initial value problems, integral equations and fractional order integral equation. It is proved that those new transforms in the class of Laplace transform which are introduced during last few decades are a special case of this general transform. It is shown that there is no advantage between theses transforms unless for special problems. It has shown that this new integral transform covers those exiting transforms such as Laplace, Elzaki and Sumudu transforms for different value of p (s) and q (s). We used this new transform for solving ODE, integral equations and fractional integral equations. Also, we can introduce new integral transforms by using this new general integral transform. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
8. Mathematical micro–macro modeling of fully coupled nonlinear magneto-elastic reinforced composites.
- Author
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Tassi, Nada, Azrar, Lahcen, Fakri, Nadia, and Alnefaie, Khaled
- Subjects
- *
MATHEMATICAL models , *NEWTON-Raphson method , *INTEGRAL equations , *NONLINEAR equations , *MAGNETIC fields , *DIGITAL image correlation , *NONLINEAR oscillators - Abstract
In this paper, integral equation formulations and field-dependent micromechanical modeling of global nonlinear magneto-mechanical behavior of magneto-elastic composites under high strain and magnetic field are elaborated. The modeling is obtained based on an extension of micro–macro transition inclusion problem to nonlinear behavior using field-dependent and highly nonlinear localization tensors. A methodological procedure is elaborated based on newly introduced strain and magnetic field-dependent Green tensors, strain and magnetic field-dependent integral equations linked to tensors of Eshelby and micromechanical approaches. The field-dependent global moduli are predicted based on the Mori–Tanaka approach and self-consistent method. Iterative incremental schemes based on the Newton–Raphson and fixed-point algorithms are examined and established precise semi-analytic equations of the effective magneto-elastic properties of composites that are dependent on the magnetic-strain field for different types of inclusions. A numerical code is elaborated for numerical predictions and the obtained field-dependent effective magneto-elastic coefficients are obtained and presented for various volume fractions of inclusion, types and shapes of the reinforced nonlinear composites. • Nonlinear micromechanical modeling of fully coupled magneto-elastic under large deformation and high magnetic field. • Magnetic-Strain dependent Green tensors and associated localization tensors. • Iterative incremental schemes for semi-analytical magnetic-strain field dependent effective magneto-elastic properties. • Magneto-mechanical field dependent effective properties for several types of matrix and inclusions phases. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. hp non-conforming a priori error analysis of an Interior Penalty Discontinuous Galerkin BEM for the Helmholtz equation.
- Author
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Nadir-Alexandre, Messai and Sébastien, Pernet
- Subjects
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HELMHOLTZ equation , *ERROR analysis in mathematics , *A priori , *INTEGRAL equations , *BOUNDARY element methods - Abstract
This work is concerned with the construction and the hp non-conforming a priori error analysis of a Discontinuous Galerkin DG numerical scheme applied to the hypersingular integral equation related to the Helmholtz problem in 3D. The main results of this article are an error bound in a norm suited to the problem and in the L 2 -norm. Those bounds are quasi-optimal for the h -convergence and the p -convergence. Various formulation choices and penalty functions are theoretically discussed. In particular we show that a penalty function of the shape h 2 p leads to a quasi-optimal convergence of the scheme. Some numerical experiments confirm the expected rates of convergence and the effect of the penalty function. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
10. Galerkin method with new quadratic spline wavelets for integral and integro-differential equations.
- Author
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Černá, Dana and Finěk, Václav
- Subjects
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INTEGRO-differential equations , *INTEGRAL equations , *GALERKIN methods , *SPLINES , *SPARSE matrices , *TENSOR products - Abstract
The paper is concerned with the wavelet-Galerkin method for the numerical solution of Fredholm linear integral equations and second-order integro-differential equations. We propose a construction of a quadratic spline-wavelet basis on the unit interval, such that the wavelets have three vanishing moments and the shortest support among such wavelets. We prove that this basis is a Riesz basis in the space L 2 0 , 1. We adapt the basis to homogeneous Dirichlet boundary conditions, and using a tensor product we construct a wavelet basis on the hyperrectangle. We use the wavelet-Galerkin method with the constructed bases for solving integral and integro-differential equations, and we show that the matrices arising from discretization have uniformly bounded condition numbers and that they can be approximated by sparse matrices. We present numerical examples and compare the results with the Galerkin method using other quadratic spline wavelet bases and other methods. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
11. A family of measures of noncompactness in the Hölder space [formula omitted] and its application to some fractional differential equations and numerical methods.
- Author
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Amiri Kayvanloo, Hojjatollah, Khanehgir, Mahnaz, and Allahyari, Reza
- Subjects
- *
FRACTIONAL differential equations , *BOUNDARY value problems , *HOLDER spaces , *EXISTENCE theorems , *FUNCTION spaces , *FIXED point theory - Abstract
In this paper, we prove the existence of solutions for the following fractional boundary value problem c D α u (t) = f (t , u (t)) , α ∈ (n , n + 1) , 0 ≤ t < + ∞ , u (0) = 0 , u ′ ′ (0) = 0 , ... , u (n) (0) = 0 , lim t → + ∞ c D α − 1 u (t) = β u (ξ). The considerations of this paper are based on the concept of a new family of measures of noncompactness in the space of functions C n , γ (R +) satisfying the Hölder condition and a fixed point theorem of Darbo type. We also provide an illustrative example in support of our existence theorems. Finally, to credibility, we apply successive approximation and homotopy perturbation method to find solution of the above problem with high accuracy. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
12. Construction of simple majorizing sequences for iterative methods.
- Author
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Ezquerro, J.A. and Hernández-Verón, M.A.
- Subjects
- *
ITERATIVE methods (Mathematics) , *NEWTON-Raphson method , *CONSTRUCTION , *BANACH spaces - Abstract
The interest of the majorizing (scalar) sequences lies in that, from their convergence, we can deduce the convergence of an iterative method in Banach spaces. We propose a new technique to construct majorizing sequences that generalizes that given by Kantorovich for Newton's method. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
13. A collocation method based on roots of Chebyshev polynomial for solving Volterra integral equations of the second kind.
- Author
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Wang, Zewen, Hu, Xiaoying, and Hu, Bin
- Subjects
- *
VOLTERRA equations , *COLLOCATION methods , *CHEBYSHEV polynomials , *FREDHOLM equations , *NUMERICAL solutions to integral equations , *LINEAR algebra , *LINEAR equations , *KERNEL functions - Abstract
This paper mainly studies numerical solution to the Volterra integral equation of the second kind. By using the roots of Chebyshev polynomial as collocation points, a new collocation method is proposed to solve the Volterra integral equation of the second kind. The proposed method firstly interpolates the product of the kernel function and the unknown solution at the roots of Chebyshev polynomial. Then, the Volterra integral equation is transformed into a system of linear algebra equations by properties of Chebyshev polynomials. Finally, the numerical solution of the Volterra integral equation is obtained by the Chebyshev polynomial interpolation. In addition, the error estimates of the proposed method are provided in a semi-posteriori sense; and numerical examples are given to show effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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14. An asymptotic solution of the integral equation for the second moment function in geometric processes.
- Author
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Pekalp, Mustafa Hilmi and Aydoğdu, Halil
- Subjects
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INTEGRAL equations , *LAPLACE transformation - Abstract
Abstract In this study, we derive an asymptotic solution of the integral equation satisfied by the second moment function M 2 t , a. We first find the Laplace transform M 2 L s , a and then obtain M 2 t , a asymptotically by inversion. Further, we have derived the asymptotic expressions of M 2 t , a for some special lifetime distributions such as exponential, gamma, Weibull, lognormal and truncated normal. Finally, the asymptotic solution is compared with the numerical solution to evaluate its performance. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
15. Extending the domain of starting points for Newton’s method under conditions on the second derivative.
- Author
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Argyros, I.K., Ezquerro, J.A., Hernández-Verón, M.A., and Magreñán, Á.A.
- Subjects
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DERIVATIVES (Mathematics) , *NEWTON-Raphson method , *INTEGRAL equations , *ERROR analysis in mathematics , *COMPUTATIONAL complexity - Abstract
In this paper, we propose a center Lipschitz condition for the second Fréchet derivative together with the use of restricted domains in order to improve the domain of starting points for Newton’s method. In addition, we compare the new result with an older one and see that the former improves the latter. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
16. Nonlinear micromechanical modeling of fully coupled piezo-elastic composite under large deformation and high electric field.
- Author
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Tassi, Nada, Azrar, Lahcen, Fakri, Nadia, and Aljinaidi, Abdulmalik
- Subjects
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ELECTRIC fields , *PIEZOELECTRIC composites , *ELECTRIC field effects , *NEWTON-Raphson method , *PIEZOELECTRIC materials , *ALGEBRAIC equations - Abstract
This paper presents mathematical modeling and predictions of effective nonlinear electro-mechanical behavior of piezoelectric materials under large deformation and high electric field. The heterogeneous inclusion problem is extended to investigate the fields dependent electro-elastic behaviors under high fields. The associated strain field dependent Green tensors are introduced. The field dependent interaction tensors, related to Eshelby's tensors, are explicitly formulated and used to derive micromechanical models based on the Mori–Tanaka approach and the self-consistent model. Due to electric-strain field dependence nonlinear algebraic tensors equations are resulted. Iterative incremental schemes based on the Newton–Raphson algorithm are elaborated and explicit semi-analytical formulations of electric-strain field dependent effective electro-elastic moduli of piezoelectric multi-phase composites are obtained for various inclusion types. Strain and electric field's effects on effective properties can be analyzed for various electro-elastic composites. Numerical results of field dependent effective electro-mechanical properties are given for several inclusion's volume fraction and shapes as well as types of matrix and inclusions phases. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
17. Starting points for Newton’s method under a center Lipschitz condition for the second derivative.
- Author
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Ezquerro, J.A., Hernández-Verón, M.A., and Magreñán, Á.A.
- Subjects
- *
NEWTON-Raphson method , *INTEGRAL equations , *NONLINEAR operators , *CONVEX domains - Abstract
We analyze the semilocal convergence of Newton’s method under a center Lipschitz condition for the second derivative of the operator involved different from that used by other authors until now. In particular, we propose to center the Lipschitz condition for the second derivative in a different point from that where Newton’s method starts. This allows us to obtain different starting points for Newton’s method and modify the domain of starting points. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
18. On global convergence for an efficient third-order iterative process
- Author
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Miguel Ángel Hernández-Verón, José Antonio Ezquerro, and Á. Alberto Magreñán
- Subjects
Iterative and incremental development ,Applied Mathematics ,010103 numerical & computational mathematics ,01 natural sciences ,Integral equation ,Chebyshev filter ,010101 applied mathematics ,Computational Mathematics ,Third order ,Operator (computer programming) ,Convergence (routing) ,Applied mathematics ,0101 mathematics ,Mathematics ,Second derivative - Abstract
We establish a global convergence result for an efficient third-order iterative process which is constructed from Chebyshev's method by approximating the second derivative of the operator involved by combinations of the operator. In particular, from the use of auxiliary points, we provide domains of restricted global convergence that allow obtaining balls of convergence and locate solutions. Finally, we use different numerical examples, including a Chandrashekar's integral equation problem, to illustrate the study.
- Published
- 2022
19. Overall elastic properties of composites from optimal strong contrast expansion.
- Author
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To, Quy-Dong, Nguyen, Minh-Tan, Bonnet, Guy, Monchiet, Vincent, and To, Viet-Thanh
- Subjects
- *
COMPOSITE materials , *ELASTICITY , *INTEGRAL equations , *FOURIER transforms , *VON Neumann algebras - Abstract
In this paper, we propose a new systematic procedure of estimating elastic properties of composites constituted of two phases, matrix and inclusions. A class of integral equations based on eigenstrain (or eigenstress) with the matrix as reference material is constructed with an explicit form in Fourier space. Each integral equation belonging to this class can yield estimates of the overall elastic tensor via Neumann series expansion. The best estimates and series are selected based on the convergence rate criteria of the series, i.e the spectral radius must be minimized. The optimized series is convergent for any finite contrast between inclusions and matrix. Applying the optimized series and the associated estimates to different microstructures yields very satisfying results when compared with the related full solution. For the case of a random distribution of spherical inclusions, exact relations between the elastic tensor and n th order structure factors are demonstrated. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
20. An elastoplastic model for the analysis of a driven pile extended with a micropile.
- Author
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Justo, Enrique, Vázquez-Boza, Manuel, Justo, Jose Luis, and Arcos, Jose Luis
- Subjects
- *
ELASTOPLASTICITY , *PILE anchors (Foundation engineering) , *AXIAL loads , *STRESS concentration , *FINITE element method - Abstract
An elastoplastic model for the analysis of a driven pile extended at the bottom with a micropile under axial load is presented. The model is an extension of the integral equation method of Poulos and Davis. The finite-difference scheme used to obtain the pile displacements is reformulated to take into account the discontinuity in the stress distribution at the joint between pile and micropile. The results obtained with the proposed method are compared with the outcomes of a more sophisticated finite element simulation, and also with data from full-scale load tests. Reasonably good agreement is obtained in both cases. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
21. Qualitative properties of solutions of an integral equation associated with the Benjamin–Ono–Zakharov–Kuznetsov operator.
- Author
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Esfahani, Amin
- Abstract
We study qualitative properties of solutions of an integral equation associated the Benjamin–Ono–Zakharov–Kuznetsov operator. We establish the regularity of the positive solutions without the assumption of being in fractional Sobolev–Liouville spaces. Moreover we show that the solutions are axially symmetric. Furthermore we establish Lipschitz continuity and the decay rate of the solutions. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
22. Valuing American floating strike lookback option and Neumann problem for inhomogeneous Black–Scholes equation.
- Author
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Jeon, Junkee, Han, Heejae, and Kang, Myungjoo
- Subjects
- *
NEUMANN problem , *BLACK-Scholes model , *MATHEMATICAL formulas , *BOUNDARY value problems , *MELLIN transform - Abstract
This paper presents our study of American floating strike lookback options written on dividend-paying assets. The valuation of these options can be mathematically formulated as a free boundary inhomogeneous Black–Scholes PDE with a Neumann boundary condition, which we, by using a Mellin transform, convert into a relatively simple ordinary differential equation with Dirichlet boundary conditions. We then use these results to derive an integral equation that can be used to calculate the price of American floating strike lookback options. In addition, we also used Mellin transforms to derive the closed-form of the perpetual case. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
23. Frictionless contact of a rigid disk with the face of a penny-shaped crack in a transversely isotropic solid.
- Author
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Shahmohamadi, M., Khojasteh, A., and Rahimian, M.
- Subjects
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CRACK initiation (Fracture mechanics) , *ISOTROPIC properties , *CONTINUUM mechanics , *NUMERICAL analysis , *STIFFNESS (Mechanics) , *STRESS intensity factors (Fracture mechanics) - Abstract
In the framework of linear elastic continuum mechanics, an analytical formulation is presented for the axisymmetric axial interaction of a rigid disk in frictionless contact with the face of a penny-shaped crack in a transversely isotropic solid. The problem is reduced to an integral equation and is shown to be degenerated to the formulation of isotropic materials in the literature. As the closed-form solution is not possible, by means of a numerical procedure, the obtained integral equation is solved and the accuracy of numerical procedure and mathematical formulation is verified through comparison with the available results for the relevant analysis in isotropic solids. Through several numerical displays, the effect of material anisotropy on the stiffness of the interacting system and the stress intensity factors at the tip of penny-shaped crack is surveyed. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
24. The Use of Genetic Algorithm for Construction Objects with Necessary Average Values Scattering Characteristics.
- Author
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Lvovich, I.Ya., Lvovich, Ya.E., Preobrazhenskiy, A.P., Choporov, O.N., and Sakharov, Yu.S.
- Subjects
GENETIC algorithms ,MATHEMATICAL optimization ,SCATTERING (Physics) ,RADAR cross sections ,INTEGRAL equations - Abstract
In the paper we consider the possibility of constructing models of objects that have the maximum average values of the characteristics of scattering at a certain sector of angles. For optimization of these characteristics we use genetic algorithm. We developed algorithm on the base of the dependencies of the characteristic dimensions of a hollow structure with a maximum average values of the characteristics of scattering were calculated. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
25. Partial slip contact of a rigid pin and a linear viscoelastic plate.
- Author
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Dayalan, Satish Kumar and Sundaram, Narayan K.
- Subjects
- *
STRUCTURAL plates , *VISCOELASTIC materials , *CYCLIC loads , *SINGULAR integrals , *TIME-domain analysis , *LAPLACE transformation - Abstract
This paper analyzes partial slip contact problems in the theory of linear viscoelasticity under a wide variety of loading conditions, including cyclic (fretting) loads, using a semi-analytical method. Such problems arise in applications like metal-polymer contacts in orthopedic implants. By using viscoelastic analogues of Green’s functions, the governing equations for viscoelastic partial-slip contact are formulated as a pair of coupled Singular Integral Equations (SIEs) for a conforming (pin-plate) geometry. The formulation is entirely in the time-domain, avoiding Laplace transforms. Both Coulomb and hysteretic effects are considered, and arbitrary load histories, including bidirectional pin loads and remote plate stresses, are allowed. Moreover, the contact patch is allowed to advance and recede with no restrictions. Viscoelasticity necessitates the application of the stick-zone boundary condition in convolved form, and also introduces additional convolved gap terms in the governing equations, which are not present in the elastic case. Transient as well as steady-state contact tractions are studied under monotonic ramp-hold, unload-reload, cyclic bidirectional (fretting) and remote plate loading for a three-element solid. The contact size, stick-zone size, indenter approach, Coulomb energy dissipation and surface hoop stresses are tracked during fretting. Viscoelastic fretting contacts differ from their elastic counterparts in notable ways. While they shakedown just like their elastic counterparts, the number of cycles to attain shakedown states is strongly dependent on the ratio of the load cycle time to the relaxation time. Steady-state cyclic bulk hysteretic energy dissipation typically dominates the cyclic Coulomb dissipation, with a more pronounced difference at slower load cycling. However, despite this, it is essential to include Coulomb friction to obtain accurate contact stresses. Moreover, while viscoelastic steady-state tractions agree very well with the elastic tractions using the steady-state shear modulus in load-hold analyses, viscoelastic fretting tractions in shakedown differ considerably from their elastic counterparts. Additionally, an approximate elastic analysis misidentifies the edge of contact by as many as 7 degrees in fretting, showing the importance of viscoelastic contact analysis. The SIE method is not restricted to simple viscoelastic networks and is tested on a 12-element solid with very long time scales. In such cases, the material is effectively always in a transient state, with no steady edge-of-contact. This has implications for fretting crack nucleation. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
26. Integral representation of vega for American put options.
- Author
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Liu, Yanchu, Cui, Zhenyu, and Zhang, Ning
- Abstract
There is an inaccurate formula in Huang et al. (1996). In fact, a substantial term is missing in their equation (14) for computing the value of an important option hedging parameter, i.e., the vega. We fix it in this note by providing its correct form and characterizing an associated (new) integral equation. Some related explanations and arguments are also corrected. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
27. A regularized boundary element formulation with weighted-collocation and higher-order projection for 3D time-domain elastodynamics.
- Author
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Pak, Ronald Y.S. and Bai, Xiaoyong
- Subjects
- *
ELASTODYNAMICS , *STRUCTURAL dynamics , *EARTHQUAKE resistant design , *INDUCED seismicity , *BOUNDARY element methods - Abstract
To advance Time-Domain Boundary Element Methods (TD-BEMs), a generalized direct time-integration solution method for three-dimensional elastodynamics is presented in this paper. On the basis of a general decomposition of time-dependent point-load Green's functions into a singular and regular part, a regularized boundary integral equation for the time domain is formulated and implemented via a variable-weight multi-step collocation scheme that allows for different orders of time projection for the boundary displacements and tractions. The benefits and possibilities of improved performance by suitable collocation weights and the solution projection choices are illustrated via two benchmark finite-domain and infinite-domain problems. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
28. A new non-parametric estimator for instant system availability.
- Author
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Huang, Kai and Mi, Jie
- Subjects
- *
PARAMETER estimation , *ASYMPTOTIC expansions , *COMPUTATIONAL statistics , *COMPUTER simulation , *INTEGRAL equations - Abstract
Instant availability of a repairable system is a very important measure of its performance. Among the extensive literature in system availability of the steady state, which is the limit of instant availability as time approaches infinity, many methods and approaches have been explored. However, less has been done on instant system availability owing to its theoretical and computational challenges. A new non-parametric estimator of instant availability is proposed. This estimator is both asymptotically consistent and efficient in numerical computation. Multiple numerical simulations are presented to demonstrate the performance of the new estimator. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
29. A parallelizable direct solution of integral equation methods for electromagnetic analysis.
- Author
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Wang, Kechen, Li, Mengmeng, Ding, Dazhi, and Chen, Rushan
- Subjects
- *
INTEGRAL equations , *ELECTROMAGNETIC wave scattering , *MATHEMATICAL decomposition , *IMPEDANCE matrices , *STOCHASTIC convergence - Abstract
A parallelizable direct solution of integral equation methods is proposed for electromagnetic scattering analysis in low to intermediate frequency regime. There are mainly two parts of the proposed direct solution: forward decomposition and backward substitution. For the forward decomposition, the dense impedance matrix is decomposed of the product of several block diagonal matrices implicitly, which is shown to be O ( N log 2 N ) for both memory and CPU time cost. The final solutions are obtained with several matrix vector products (MVPs) in the part of backward substitution with O ( N log 2 N ) complexity as well. Both forward decomposition and backward substitution can be parallelized because of the group independence. Furthermore, an effective preconditioner with a reasonable selection criterion of the diagonal blocks region is proposed to accelerate the convergence of the iterative solver. The proposed solution is independent of the Green's function, and it is suitable for all the integral equation methods. Without loss of generality, the solution is proposed to solve the electric field integral equation (EFIE) in this work. Numerical tests demonstrate the effectiveness of the proposed solution for the electromagnetic analysis, especially for multiscale structures. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
30. Nested equivalence source approximation with adaptive group size for multiscale simulations.
- Author
-
Li, Mengmeng, Ding, Dazhi, Li, Jipeng, and Chen, Rushan
- Subjects
- *
MATHEMATICAL equivalence , *APPROXIMATION theory , *ELECTRIC field integral equations , *OCTREES (Computer graphics) , *COUPLING reactions (Chemistry) - Abstract
A nested equivalence source approximation (NESA) of the electric field integral equation with adaptive octree is explored for multiscale problems in this paper. The NESA low rank approximation formulation previously for far coupling groups with uniform size is derived for coupling groups with adaptive size, while preserves the kernel free and multiscale property. With the proposed adaptive group decomposition, reasonable separation of near and far region can be obtained. Numerical tests of the conformal and non-conformal multiscale electromagnetic simulation to show the validity of the adaptive NESA. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
31. Liquid-vapour coexistence line and percolation line of rose water model.
- Author
-
Ogrin, Peter and Urbic, Tomaz
- Subjects
- *
PHASE transitions , *PERCOLATION theory , *PERCOLATION , *MONTE Carlo method , *PHASE diagrams , *ROSES - Abstract
• Wertheim's thermodynamic perturbation theory were applied to the rose model. • Liquid part of phase diagram were calculated. • Two critical points are observed. Monte Carlo simulations and Wertheim's thermodynamic perturbation theory (TPT) are used to predict the phase diagram and percolation curve for the simple two-dimensional rose model of water. In the rose model of water, the water molecules are modelled as two-dimensional Lennard-Jones disks, with additional rose potentials for orientation dependent pairwise interactions that mimic formation of hydrogen bonds. Modifying both the shape and range of a 3-petal rose function, it was constructed an efficient and dynamical mimic of the 2D Mercedes Benz (MB) water model and experimental water. The liquid part of the phase space is explored using grand canonical Monte Carlo simulations and two versions of Wertheim's TPT for associative fluids. We find that the theory reproduces well the physical properties of hot water but is less successful at capturing the more structured hydrogen bonding that occurs in cold water. In addition to reporting the phase diagram and percolation curve of the model, it is shown that the improved TPT predicts the phase diagram rather well, while the standard one predicts a phase transition at lower temperatures. For the percolation line, both versions have problems predicting the correct position of the line at high temperatures. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
32. The numerical solution of scattering by infinite rough interfaces based on the integral equation method.
- Author
-
Li, Jianliang, Sun, Guanying, and Zhang, Ruming
- Subjects
- *
INFINITY (Mathematics) , *NUMERICAL analysis , *NUMERICAL solutions to integral equations , *INTEGRAL operators , *SOUND wave scattering - Abstract
In this paper, we describe a Nyström integration method for the integral operator T which is the normal derivative of the double-layer potential arising in problems of two-dimensional acoustic scattering by infinite rough interfaces. The hypersingular kernel and unbounded integral interval of T are the key difficulties. By using a mollifier, we separately deal with these two difficulties and propose its Nyström integration method. Furthermore, we establish convergence of the method. Finally, we apply the method to the scattering problem by infinite rough interfaces and carry out some numerical experiments to show the validity. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
33. The nonclassical diffusion approximation to the nonclassical linear Boltzmann equation.
- Author
-
Vasques, Richard
- Subjects
- *
APPROXIMATION theory , *NONCLASSICAL mathematical logic , *BOLTZMANN'S equation , *MEAN square algorithms , *INTEGRAL equations - Abstract
We show that, by correctly selecting the probability distribution function p ( s ) for a particle’s distance-to-collision, the nonclassical diffusion equation can be represented exactly by the nonclassical linear Boltzmann equation for an infinite homogeneous medium. This choice of p ( s ) preserves the true mean-squared free path of the system, which sheds new light on the results obtained in previous work. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
34. On reconstruction of thermalphysic characteristics of functionally graded hollow cylinder.
- Author
-
Nedin, R., Nesterov, S., and Vatulyan, A.
- Subjects
- *
FUNCTIONALLY gradient materials , *NONLINEAR systems , *INVERSE problems , *LAPLACE transformation , *THERMAL conductivity , *COEFFICIENTS (Statistics) - Abstract
An inverse coefficient problem of thermal conductivity for a functionally graded hollow cylinder is considered. After applying the Laplace transform, the direct thermal conductivity problem is solved by using two methods: (1) based on a reduction to the Fredholm integral equation of the 2nd kind; (2) by means of the Galerkin method. A comparison of the direct problem solving techniques is provided. The nonlinear inverse problem is solved on the basis of an iterative process; at every step of the latter the linear Fredholm integral equation of the 1st kind is solved. Results of the computational experiments on a reconstruction of variation laws of thermal conductivity and specific volumetric heat capacity are presented. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
35. Simultaneous recovery of the temperature and species concentration from integral equation model.
- Author
-
Wang, Liyan, Zhou, Bin, and Liu, Jijun
- Subjects
- *
INTEGRAL equations , *KERNEL functions , *ABSORPTION spectra , *PARAMETERS (Statistics) , *TEMPERATURE effect - Abstract
Absorption spectroscopy is an advanced tool for flow diagnostics in measuring multiple parameters of species. Such kinds of problems can be modeled by some integral equations with known kernel, aiming to the determination of the integrands from their integration values along all possible paths of injected lasers. This paper considers the parameters detection problems in combustion process, with the purpose of recovering the gas temperature and the concentration of burned gas simultaneously using injected lasers along two directions with multiple frequencies. After establishing the nonlinear integral equations describing the energy absorption process, this ill-posed model is transformed into a nonlinear optimization problem with some penalty terms. Then we present an alternative iteration scheme (AIS) to solve this problem. The convergence of the iterative sequence for AIS algorithm together with the estimate on the value of cost functional is established, ensuring that AIS can indeed generate a satisfactory approximate solution to the original optimization problem. Numerical implementations using simulant data are presented to show the validity of the proposed scheme. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
36. An integral equation approach for the valuation of American-style down-and-out calls with rebates.
- Author
-
Le, Nhat-Tan, Zhu, Song-Ping, and Lu, Xiaoping
- Subjects
- *
INTEGRAL equations , *REBATES , *OPTIONS (Finance) , *FOURIER transforms , *PARAMETER estimation - Abstract
In this paper, an integral equation approach is adopted to price American-style down-and-out calls. Instead of using the probability theory as used in the literature, we use the continuous Fourier sine transform to solve the partial differential equation system governing the option prices. As a way of validating our approach, we show that the “early exercise premium representation” for American-style down-and-out calls without rebate can be re-derived by using our approach. We then examine the case that time-dependent rebates are included in the contract of American-style down-and-out calls. As a result, a more general integral representation for the price of an American-style down-and-out call, with the presence of an extra term associated with the rebate, is obtained. Our numerical method based on the newly-derived integral representation appears to be efficient in computing the price and the hedging parameters for American-style down-and-out calls with rebates. In addition, significant effects of rebates on the option prices and the optimal exercise boundaries are illustrated through selected numerical results. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
37. Transient dynamic stress intensity factors around three stacked parallel cracks in an infinite medium during passage of an impact normal stress.
- Author
-
Itou, Shouetsu
- Subjects
- *
STRESS intensity factors (Fracture mechanics) , *FRACTURE mechanics , *IMPACT (Mechanics) , *STRAINS & stresses (Mechanics) , *LAPLACE transformation - Abstract
Transient dynamic stresses around three stacked parallel cracks in an infinite elastic plate are estimated for an incident impact stress wave impinging normal to the cracks. Using Fourier and Laplace transform techniques, the boundary conditions are reduced to six simultaneous integral equations in the Laplace domain. The differences in the displacements inside the cracks are expanded in a series of functions that have zero value outside the cracks. The Schmidt method is used to solve the unknown coefficients in the series such that the conditions inside the cracks are satisfied. The stress intensity factors are defined in the Laplace domain, and these are inverted using the numerical method. The stress intensity factors are calculated numerically for some crack configurations. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
38. Horn effect prediction based on the time domain boundary element method.
- Author
-
Zhang, Yang, Bi, Chuan-Xing, Zhang, Yong-Bin, and Zhang, Xiao-Zheng
- Subjects
- *
BOUNDARY element methods , *INTEGRAL equations , *RESONANCE , *NUMERICAL analysis , *HYPERNASALITY - Abstract
A time domain boundary element method (TBEM) is applied to predict the horn effect. As the time response calculated by the time domain boundary integral equation contains the resonance components, when transformed to the frequency domain, the result will corrupt at the characteristic frequencies. To overcome this problem, a Burton–Miller-type combined time domain integral equation in half-space is applied. The resonance components are excluded in the time domain calculation, thus the corruptions are avoided in the frequency domain. As a result, the horn effect can be predicted very well at all frequencies. Compared to the frequency domain boundary element method for predicting the horn effect, the TBEM is more efficient due to the lower cost of forming coefficient matrices and solving equations. A numerical simulation is carried out to demonstrate the efficiency of the TBEM, and two experiments are conducted to validate the proposed method in predicting the horn effect. Both numerical and experimental results indicate that the proposed method is reliable and efficient in predicting the horn effect. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
39. Numerical solution of EFIE using MLPG methods.
- Author
-
Honarbakhsh, Babak
- Subjects
- *
ELECTRIC field integral equations , *MESHFREE methods , *GALERKIN methods , *GREEN'S functions , *DISCRETIZATION methods - Abstract
Meshless local Petrov-Galerkin (MLPG) methods are applied to the electric-field integral equation (EFIE), including seven previously reported schemes and two new suggested. The required dyadic weightings are provided. Especially, the dyadic Green’s function for the differential part of the equation is derived for the first time. Guidelines are suggested for both meshless discretization and efficient implementation. It is shown that by proper selection of the MLPG scheme and its parameters, the stiffness matrix corresponding to the problem can be computed using closed-form expressions, without the need to perform numerical integration. It is shown that using weightings other than the Dirac delta can significantly improve the convergence trend of the meshless solution and increase the accuracy up to two orders of magnitude. It is, also, demonstrated that a meshfree IE solver can more accurately track singularities of the surface current density at conductive edges compared to the method of moments (MoM). In addition, it is shown that such solvers can potentially supersede high-order (HO) MoM as their mesh-based counterpart. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
40. Domain decomposition scheme with equivalence spheres for the analysis of aircraft arrays in a large-scale range.
- Author
-
Su, Ting, Li, Mengmeng, and Chen, Rushan
- Subjects
- *
MATHEMATICAL decomposition , *MATHEMATICAL equivalence , *AIRPLANES , *RADIAL basis functions , *ADAPTIVE computing systems - Abstract
we propose a domain decomposition scheme for solving scattering problem from multi-objects distribution in a large-scale range. Each sub-object is enclosed by an equivalence sphere. The scheme is composed of the equivalence process and translation process. In the equivalence process, the scattering fields from the sub-object are produced by the equivalence mode currents on the equivalence sphere. The equivalence mode currents are the current expansion of the body of revolution (BoR) basis functions, which are transformed from the current expansion of the Rao–Wilton-Glisson (RWG) basis functions. The multilevel fast multipole algorithm (MLFMA) is employed to accelerate the equivalence process. In the translation process, the mode translation matrices are obtained based on the BoR basis functions and the coordinate conversion method for computing the interactions among the equivalence spheres. The adaptive cross algorithm (ACA) is used to accelerate the evaluation of mode translation matrices. The proposed approach is very efficient for analysis of the objects distributed in a large-scale range. Numerical results demonstrate that the approach provides significant improvements in terms of memory requirements. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
41. Solution of Cauchy type singular integral equations of the first kind by using differential transform method.
- Author
-
Abdulkawi, M.
- Subjects
- *
CAUCHY integrals , *SINGULAR integrals , *LINEAR equations , *MATHEMATICAL convolutions , *KERNEL functions , *MATHEMATICAL transformations - Abstract
The differential transform method is extended to solve the Cauchy type singular integral equations (CSIEs) over a finite interval. New theorems for transformation of Cauchy singular integrals are given with proofs. Approximate solutions of CSIEs with two types of kernels, Degenerate and convolution, are obtained. The system of linear equations for characteristic equation is solved analytically. Numerical results are shown to illustrate the efficiency and accuracy of the present method. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
42. Faster computation of the Karhunen–Loève expansion using its domain independence property.
- Author
-
Pranesh, Srikara and Ghosh, Debraj
- Subjects
- *
MATHEMATICAL expansion , *MATHEMATICAL domains , *INDEPENDENCE (Mathematics) , *COEFFICIENTS (Statistics) , *STOCHASTIC processes , *DISCRETIZATION methods - Abstract
The goal of this work is to reduce the cost of computing the coefficients in the Karhunen–Loève (KL) expansion. The KL expansion serves as a useful and efficient tool for discretizing second-order stochastic processes with known covariance function. Its applications in engineering mechanics include discretizing random field models for elastic moduli, fluid properties, and structural response. The main computational cost of finding the coefficients of this expansion arises from numerically solving an integral eigenvalue problem with the covariance function as the integration kernel. Mathematically this is a homogeneous Fredholm equation of second type. One widely used method for solving this integral eigenvalue problem is to use finite element (FE) bases for discretizing the eigenfunctions, followed by a Galerkin projection. This method is computationally expensive. In the current work it is first shown that the shape of the physical domain in a random field does not affect the realizations of the field estimated using KL expansion, although the individual KL terms are affected. Based on this domain independence property, a numerical integration based scheme accompanied by a modification of the domain, is proposed. In addition to presenting mathematical arguments to establish the domain independence, numerical studies are also conducted to demonstrate and test the proposed method. Numerically it is demonstrated that compared to the Galerkin method the computational speed gain in the proposed method is of three to four orders of magnitude for a two dimensional example, and of one to two orders of magnitude for a three dimensional example, while retaining the same level of accuracy. It is also shown that for separable covariance kernels a further cost reduction of three to four orders of magnitude can be achieved. Both normal and lognormal fields are considered in the numerical studies. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
43. A model-free method for extracting interaction potential between protein molecules using small-angle X-ray scattering.
- Author
-
Sumi, Tomonari, Imamura, Hiroshi, Morita, Takeshi, and Nishikawa, Keiko
- Subjects
- *
EXTRACTION (Chemistry) , *CHEMICAL potential , *PROTEIN-protein interactions , *X-ray scattering , *SOLUTION (Chemistry) - Abstract
A small-angle X-ray scattering has been used to probe protein–protein interaction in solution. Conventional methods need to input modeled potentials with variable/invariable parameters to reproduce the experimental structure factor. In the present study, a model-free method for extracting the excess part of effective interaction potential between protein molecules in solutions over an introduced hard-sphere potential by using experimental data of small-angle X-ray scattering is presented on the basis of liquid-state integral equation theory. The reliability of the model-free method is tested by the application to experimentally derived structure factors for dense lysozyme solutions with different solution conditions [Javid et al., Phys. Rev. Lett. 99 , 028101 (2007), Schroer et al., Phys. Rev. Lett. 106 , 178102 (2011)]. The structure factors calculated from the model-free method agree well with the experimental ones. The model-free method provides the following picture of the lysozyme solution: these are the stabilization of contact-pair configurations, large activation barrier against their formations, and screened Coulomb repulsion between the charged proteins. In addition, the model-free method will be useful to verify whether or not a model for colloidal system is acceptable to describing protein–protein interaction. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
44. The principle of equivalent eigenstrain for inhomogeneous inclusion problems.
- Author
-
Ma, Lifeng and Korsunsky, Alexander M.
- Subjects
- *
EIGENANALYSIS , *STRAIN theory (Chemistry) , *INHOMOGENEOUS materials , *ELASTIC deformation , *RESIDUAL stresses , *INTEGRAL equations , *PHASE transitions - Abstract
In this paper, based on the principle of virtual work, we formulate the equivalent eigenstrain approach for inhomogeneous inclusions. It allows calculating the elastic deformation of an arbitrarily connected and shaped inhomogeneous inclusion, by replacing it with an equivalent homogeneous inclusion problem, whose eigenstrain distribution is determined by an integral equation. The equivalent homogeneous inclusion problem has an explicit solution in terms of a definite integral. The approach allows solving the problems about inclusions of arbitrary shape, multiple inclusion problems, and lends itself to residual stress analysis in non-uniform, heterogeneous media. The fundamental formulation introduced here will find application in the mechanics of composites, inclusions, phase transformation analysis, plasticity, fracture mechanics, etc. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
45. Shear traction and sticking scope of frictional contact between two elastic cylinders.
- Author
-
Zhao, Yaping and Zhang, Yimin
- Subjects
- *
SHEAR (Mechanics) , *ENGINE cylinders , *CONTACT mechanics , *FRICTION materials , *ELASTICITY , *SINGULAR integrals , *ENGINE design & construction - Abstract
In this study, the frictional contact with partial slide between two dissimilar elastic cylinders is considered. According to the Spence׳s self-similarity condition, a system of singular integral equations is constructed with respect to the normal pressure and the shear traction in the contacting area. Based on the Goodman׳s hypothesis, the preceding system is uncoupled. From this, the tangential load in the central sticking zone is possible to be obtained analytically by means of the theory on the singular integral equation. Besides, a nonlinear equation in regard to the ratio of the adhesive and slip zone sizes is derived on the basis of the continuity of the tangential load. The sticking zone size can thus be determined by solving the nonlinear equation mentioned above iteratively. The problem in question is additionally solved by utilizing numerical method to make verification and validation of the theory and the related prevision found in the present paper. Numerical examples are provided to instantiate the theroy and method proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
46. Electromagnetic scattering analysis using nonconformal meshes and monopolar curl-conforming basis functions.
- Author
-
Zhang, Liming, Deng, Ali, Zhang, Yiqing, Meng, Xianzhu, and Lv, Zengtao
- Subjects
- *
ELECTROMAGNETIC wave scattering , *MESHFREE methods , *RADIAL basis functions , *SCHEMES (Algebraic geometry) , *ELECTRIC conductivity , *ELECTRIC fields - Abstract
A scheme for electromagnetic scattering analysis of perfect electric conducting (PEC) objects using nonconformal meshes is developed in this paper. The difference of the integral operators for the electric field integral equation (EFIE) and the magnetic field integral equation (MFIE) are analyzed in detail. It is shown theoretically that basis functions used to expand the surface currents for the MFIE may not necessarily be divergence-conforming. The nonconformal meshes and monopolar n × RWG basis functions are used together to solve the MFIE. Details for the implementation of the proposed method are presented. The method is verified through the numerical results for electromagnetic scattering analysis from several PEC objects. It is shown that this method is a suitable choice for using nonconformal meshes when solving electromagnetic scattering problems with the MFIE. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
47. A comprehensive study on Green׳s functions and boundary integral equations for 3D anisotropic thermomagnetoelectroelasticity.
- Author
-
Pasternak, Iaroslav, Pasternak, Roman, and Sulym, Heorhiy
- Subjects
- *
GREEN'S functions , *BOUNDARY element methods , *ANISOTROPY , *FORCE & energy , *ELASTICITY - Abstract
The paper derives Somigliana type boundary integral equations for 3D thermomagnetoelectroelasticity of anisotropic solids. In the absence of distributed volume heat and body forces these equations contain only boundary integrals. Besides all of the obtained terms of integral equations are to be calculated in the real domain, which is advantageous to the known equations that can contain volume integrals or whose terms should be calculated in the mapped temperature domain. All kernels of the derived integral equations and the 3D thermomagnetoelectroelastic Green׳s function for a point heat are obtained explicitly based on the Radon transform technique. Verification of the obtained equations and fundamental solutions is provided. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
48. Optimal homotopy asymptotic method for solving Volterra integral equation of first kind.
- Author
-
Khan, N., Hashmi, M. S., Iqbal, S., and Mahmood, T.
- Subjects
HOMOTOPY theory ,INTEGRAL equations ,NONLINEAR equations ,STABILITY theory ,NUMERICAL solutions to Voterra equations - Abstract
In this paper, authors demonstrate the efficiency of optimal homotopy asymptotic method (OHAM). This is done by solving nonlinear Volterra integral equation of first kind. OHAM is applied to Volterra integral equations which involves exponential, trigonometric function as their kernels. It is observed that solution obtained by OHAM is more accurate than existing techniques, which proves its validity and stability for solving Volterra integral equation of first kind. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
49. Asymptotic analysis in the anti-plane high-frequency diffraction by interface cracks.
- Author
-
Sumbatyan, M.A. and Remizov, M.Yu.
- Subjects
- *
INTERFACES (Physical sciences) , *ELASTICITY , *WIENER integrals , *WIENER-Hopf equations , *INTEGRAL equations , *PROBLEM solving - Abstract
Abstract: In the anti-plane problem about a high-frequency diffraction by an interface crack located between two different elastic materials we propose a new asymptotic approach, which reduces the problem to the Wiener–Hopf integral equations. The key point of the method is a factorization of the symbolic function which is performed in an efficient way. As a result, the leading asymptotic term is written out in an explicit analytical form. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
50. Oscillatory behavior of integro-dynamic and integral equations on time scales.
- Author
-
Grace, S.R. and Zafer, A.
- Subjects
- *
NUMERICAL solutions to integral equations , *ASYMPTOTIC theory in integral equations , *OSCILLATIONS , *DISCRETE systems , *PROBLEM solving , *CONTINUOUS functions - Abstract
Abstract: By making use of asymptotic properties of nonoscillatory solutions, the oscillation behavior of solutions for the integro-dynamic equation and the integral equation on time scales is investigated. Easily verifiable sufficient conditions are established for the oscillation of all solutions. The results are new for both continuous and discrete cases. The paper is concluded by an open problem. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
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