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This paper discusses the design process toward new lumped chaotic systems that originates in higher-order ordinary differential equations commonly used as description of ideal oscillators. In investigated third-order case, two chaotic oscillators were constructed. These systems are dual in the sense of vector field geometry local to fixed points. The existence of robust chaos was proved by both standard routines of numerical analysis and practical measurement. For the fourth-order oscillatory equation, the concept based on interaction between superinductor and supercapacitor was examined in detail. Since both "superelements" are active, the nonlinearity essential to the evolution of chaos is fully passive. It is demonstrated that complex motion is robust and does not represent long transient behavior or numerical artefact. The existence of chaos was verified using standard quantifiers of the flow, such as the largest Lyapunov exponents, recurrence plots, approximate entropy and sensitivity calculation. A good final agreement between theoretical assumptions and practical results will be concluded, on a visual comparison basis. [ABSTRACT FROM AUTHOR]

In this paper, the Rayleigh beam system with two dynamical boundary controls is treated. Theoretically, the well-posedness of the weak solution is obtained. Later, we discretize the system by using the Implicit Euler scheme in time and the P 3 Hermite finite element in space. In addition, we show the decay of the discrete energy and we establish some a priori error estimates. Finally, some numerical simulations are presented. [ABSTRACT FROM AUTHOR]

In this paper, we investigate an inverse problem to determine an unknown source term that has a separable-variable form in the time-fractional diffusion equation, whereby the data is obtained at a certain time. This problem is ill-posed, and we use the Landweber iterative regularization method to solve this inverse source problem. Two kinds of convergence rates are obtained by using an a priori and an a posteriori regularization parameters choice rules, respectively. Numerical examples are provided to show the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

In this paper, we investigate how the initial value belonging to spaces $W_{\sigma}(\mathbb{R}^{N})$ ( $0<\sigma

In this contribution, we deal with a posteriori error estimates and adaptivity for mixed finite element discretizations of second-order elliptic equations, which are applied to the Poisson equation. The method proposed is an extension to the one recently introduced in [10] to the case of inhomogeneous Dirichlet and Neumann boundary conditions. The residual-type a posteriori error estimator presented in this paper relies on a postprocessed and therefore improved solution for the displacement field which can be computed locally, i.e. on the element level. Furthermore, it is shown that this discontinuous postprocessed solution can be further improved by an averaging technique. With these improved solutions at hand, both upper and lower bounds on the finite element discretization error can be obtained. Emphasis is placed in this paper on the numerical examples that illustrate our theoretical results. [ABSTRACT FROM AUTHOR]

Modern constitutive models have the potential to improve the quality of engineering calculations involving non-linear anisotropic materials. The adoption of complex models in practice, however, depends on the availability of reliable and accurate solution methods for the stress point integration problem. This paper presents a modular implementation of explicit Runge–Kutta methods with error control, that is suitable for use, without change, with any rate-type constitutive model. The paper also shows how the complications caused by the algebraic constraint of conventional plasticity are resolved through a simple subloading modification. With this modification any rate-independent model can be implemented without difficulty, using the integration module as an accurate and robust standard procedure. The effectiveness and efficiency of the method are demonstrated through a comparative evaluation of second and fifth-order formulas, applied to a complex constitutive model for natural clay, full details of which are given. [ABSTRACT FROM AUTHOR]

Under the assumption of small vibrations, from deducing a space body’s kinetic energy, an isolator’s potential energy, damping dissipating energy and substituting into Lagrange’s equation, this paper establishes a multi-stage isolation system’s dynamic equations. A multi-stage isolation system’s dynamic equations can be described in a body’s local coordinates, as well as the system’s global coordinates. This paper proves that the two sets of equations are uniform. An example was calculated by the newly deduced equations and the finite element method. The natural frequencies of the system show that the results produced by the newly deduced equations are exact and accurate. [ABSTRACT FROM AUTHOR]

Based on the theory of elastic wave propagation in saturated soil subgrade established by the author of this paper, the axisymmetric vertical vibration of a rigid circular foundation resting on partially saturated soil subgrade which is composed of a dry elastic layer and a saturated substratum is studied. The analysis relied on the use of integral transform techniques and a pair of dual integral equations governing the vertical vibration of the rigid foundation is listed under the consideration of mixed boundary-value condition. The results are reduced to the case for saturated half-space. The set of dual integral equations are reduced to a Fredholm integral equation of the second kind and solved by numerical procedures. Numerical examples are given at the end of the paper and plots of the dynamic compliance coefficient Cv versus the dimensionless frequency a0 are presented. [ABSTRACT FROM AUTHOR]

In this paper we consider the existence of nonoscillatory solutions of higher-order neutral differential equations with distributed coefficients and delays. We use the $Banach$ contraction principle to obtain new sufficient condition for the existence of nonoscillatory solutions. [ABSTRACT FROM AUTHOR]

In this paper, we obtain one positive solution and two nontrivial solutions of a quasilinear elliptic equation with p-Laplacian, Hardy term and Hardy-Sobolev critical exponent by using variational methods and some analysis techniques. In particular, our results extend some existing ones. [ABSTRACT FROM AUTHOR]

Let TX be the full transformation semigroup on a set X and E be a non-trivial equivalence on X. The set TE (X) = { f ∊ TX : ∀(x,y) ∊ E; ( f (x), f (y)) ∊ E} is a subsemigroup of TX . For a finite totally ordered set X and a convex equivalence E on X, the set of all the orientation-preserving transformations in TE(X) forms a subsemigroup of TE(X) denoted by OPE(X). In this paper, under the hypothesis that the totally ordered set X is of cardinality mn (m,n ≥ 2) and the equivalence E has m classes such that each E-class contains n consecutive points, we calculate the cardinality of the semigroup OPE(X), and that of its idempotents. [ABSTRACT FROM AUTHOR]

Based on a complex variable boundary integral equation (CVBIE) suggested previously, this paper provides a numerical solution for the elastic inclusion problem using CVBIE. A dissimilar elastic inclusion is embedded in the infinite matrix. The original problem is decomposed into two problems. One is an interior boundary value problem (BVP) for the elastic inclusion, while the other is an exterior BVP for the matrix with notch. Both problems are connected by conventional boundary integral equations (BIEs) in complex variables. After performing discretization for the coupled BIEs, the inverse matrix technique is suggested to solve the relevant algebraic equations. Based on the properties of some integral operators, three ways for the inverse matrix technique are suggested. Several numerical examples are carried out to prove the efficiency of the suggested method. [ABSTRACT FROM AUTHOR]

This paper describes a method for numerical solution of single-phase nonstationary gas filtration in a porous medium. Linearization of the classical Leibenzon equation is performed. To solve the resulting linear equation, an efficient numerical algorithm was constructed without saturation over spatial variables and time. [ABSTRACT FROM AUTHOR]

A class of periodic initial value problems for two-dimensional Newton-Boussinesq equations are investigated in this paper. The Newton-Boussinesq equations are turned into the equivalent integral equations. With iteration methods, the local existence of the solutions is obtained. Using the method of a priori estimates, the global existence of the solution is proved. [ABSTRACT FROM AUTHOR]

This paper studies some normality criteria for a family of meromorphic functions, which improve some results of Lahiri, Lu and Gu, as well as Charak and Rieppo. [ABSTRACT FROM AUTHOR]

Sharp triangle inequality and its reverse in Banach spaces were recently showed by Mitani et al. (2007). In this paper, we present equality attainedness for these inequalities in strictly convex Banach spaces. [ABSTRACT FROM AUTHOR]

In this paper, a new reformulation of the Navier equations of motion is introduced for solving the known three-dimensional elastostatics and elastodynamics problems. At first, three decoupled equations in terms of displacement components and three decoupled equations in terms of rotation components are obtained. These equations are also invariant with respect to the choice of the coordinate system. In order to solve a three-dimensional elasticity problem based on the presented formulation, one of the three equations in terms of displacement components and the corresponding rotation equation should be solved independently. Using some relations, the other two displacement components can be obtained in terms of the mentioned displacement and rotation component. In order to verify the relations, the closed-form solutions are obtained for deflection and natural frequencies of the thick rectangular plate. The numerical results are compared with available results in the literature and it can be seen that the results of the present study are identical to those of the previous works. [ABSTRACT FROM AUTHOR]

A class of singularly perturbed boundary value problems for semilinear equations of fourth order with two parameters are considered. Under suitable conditions, using the method of lower and upper solutions, the existence and the asymptotic behavior of the solution to the boundary value problem are studied. In the present paper, the solution to the original singularly perturbed problem with two parameters has only one boundary layer. [ABSTRACT FROM AUTHOR]

In this paper we propose a parametrized Newton method for nonsmooth equations with finitely many maximum functions. The convergence result of this method is proved and numerical experiments are listed. [ABSTRACT FROM AUTHOR]

In this paper a general model for the analysis of concrete as multiphase porous material, based on the so-called Hybrid Mixture Theory, is presented. The development of the model equations, taking into account both bulk phases and interfaces of the multiphase system is described, starting from the microscopic scale. An exploration of the second law of thermodynamics is also presented: it allows defining several quantities used in the model, like capillary pressure, disjoining pressure or effective stress, and to obtain some thermodynamic restrictions imposed on the evolution equations describing the material deterioration. Then, two specific forms of the general model adapted to the case of concrete at early ages and beyond and to the case of concrete structures under fire are shown. Some numerical simulations aimed to prove the validity of the approach adopted also are presented and discussed. [ABSTRACT FROM AUTHOR]

A theoretical study of the heat transfer in the unsteady thermal boundary layer associated with the forced convection flow past a sharp, semi-infinite wedge that is started impulsively from rest and for which the constant heat flux at the walls is suddenly changed is presented in this paper. The velocity far from the wedge is given by u e ( x) = x m , where x is the coordinate measured along the wedge and m is a constant. Using appropriate non-dimensional transformations, the number of independent variables in the governing boundary-layer equations is reduced from three to two. These equations are then solved numerically for both small (initial) and large (steady-state) times. It is found that for the steady-state flow the Blasius-like solutions exist for each value of m in the range m* ≤ m < ∞, where m* is the value of the power law exponent m that corresponds to a self-similar solution profile with vanishing skin friction. [ABSTRACT FROM AUTHOR]

In this paper, a new alternating group explicit-implicit (nAGEI) scheme for dispersive equations with a periodic boundary condition is derived. This new unconditionally stable scheme has a fourth-order truncation error in space and a convergence ratio faster than some known alternating methods such as ASEI and AGE. Comparison in accuracy with the AGEI and AGE methods is presented in the numerical experiment. [ABSTRACT FROM AUTHOR]

Abstract  The present paper presents a general treatment of the transient thermoelastic stresses in a rotating nonhomogeneous anisotropic solid under compressive initial stress. The system of fundamental equations is solved by means of a boundary element method (BEM) and the numerical calculations are carried out for the temperature, displacement components and stress components. The results indicate that the effects of inhomogeneity and initial stress are very pronounced. [ABSTRACT FROM AUTHOR]

Abstract  This paper first provides a common framework for partial differential equation problems in both strong and weak form by rewriting them as generalized interpolation problems. Then it is proven that any well-posed linear problem in strong or weak form can be solved by certain meshless kernel methods to any prescribed accuracy. [ABSTRACT FROM AUTHOR]

A nonlinear mathematical model for the analysis of large deformation of frame structures with discontinuity conditions and initial displacements, subject to dynamic loads is formulated with arc-coordinates. The differential quadrature element method (DQEM) is then applied to discretize the nonlinear mathematical model in the spatial domain, An effective method is presented to deal with discontinuity conditions of multivariables in the application of DQEM. A set of DQEM discretization equations are obtained, which are a set of nonlinear differential-algebraic equations with singularity in the time domain. This paper also presents a method to solve nonlinear differential-algebra equations. As application, static and dynamical analyses of large deformation of frames and combined frame structures, subjected to concentrated and distributed forces, are presented. The obtained results are compared with those in the literatures. Numerical results show that the proposed method is general, and effective in dealing with discontinuity conditions of multi-variables and solving differential-algebraic equations. It requires only a small number of nodes and has low computation complexity with high precision and a good convergence property. [ABSTRACT FROM AUTHOR]

The progress of Mathematics during the nineteenth century was characterised both by an enormous acquisition of new knowledge and by the attempts to introduce rigour in reasoning patterns and mathematical writing. Cauchy’s presentation of Mathematical Analysis was not immediately accepted, and many writers, though aware of that new style, did not use it in their own mathematical production. This paper is devoted to an episode of this sort that took place in Spain during the first half of the century: It deals with the presentation of a method for numerically solving algebraic equations by José Mariano Vallejo, a late Spanish follower of the Enlightenment ideas, politician, writer, and mathematician who published it in the fourth (1840) edition of his book Compendio de Matemáticas Puras y Mistas, claiming to have discovered it on his own. Vallejo’s main achievement was to write down the whole procedure in a very careful way taking into account the different types of roots, although he paid little attention to questions such as convergence checks and the fulfilment of the hypotheses of Rolle’s Theorem. For sure this lack of mathematical care prevented Vallejo to occupy a place among the forerunners of Computational Algebra. [ABSTRACT FROM AUTHOR]

In this paper, the multi-symplectic formulations of the membrane free vibration equation with periodic boundary conditions in Hamilton space are considered. The complex method is introduced and a semi-implicit twenty-seven-points scheme with certain discrete conservation laws—a multi-symplectic conservation law (CLS), a local energy conservation law (ECL) as well as a local momentum conservation law (MCL)—is constructed to discrete the PDEs that are derived from the membrane free vibration equation. The results of the numerical experiments show that the multi-symplectic scheme has excellent long-time numerical behavior. [ABSTRACT FROM AUTHOR]

Abstract??Command profiles are required to move a dynamical system from rest to rest without residual vibration in a minimum time. The unity-magnitude (UM) input shaper is one of the faster input shaping techniques. However, analytical solution of the impulse time locations is impossible due to the dependent residual vibration constraint equations. Many researchers solve these by using curve fitting. In this paper, the characteristics of the UM shaping coefficients as a function of system parameters are investigated. An analysis procedure to obtain UM input shaper impulse time sequences is presented. Finally, the proposed technique is compared to the zero vibration (ZV) shaper in both response and robustness to modeling error. [ABSTRACT FROM AUTHOR]

Non-linear finite element analyses of structures (such as beams) involve construction of weak solutions for the governing equations. While a weak approach weakens the differentiability requirements of the so-called shape functions, the governing equations are only satisfied in an integral sense and not point-wise, or, even path-wise. Moreover, use of a finite mesh leads to a stiffening of the numerical model. While strong solutions obtained through some of the existing mesh-free collocation methods overcomes some of these lacunae to an extent, the quality of the numerical solutions would be considerably improved if the computational algorithm were able to faithfully reproduce (or approximate or preserve) certain geometrical features of the response surfaces or manifolds. This paper takes the first step towards realizing this objective and proposes a multi-step transversal linearization (MTL) technique for a class of non-linear boundary value problems, which are treated as conditionally dynamical systems. Numerical explorations are performed, to a limited extent, through applications to large deflection analyses of planar beams with or without plastic deformations. [ABSTRACT FROM AUTHOR]

The article presents the study of a semigroup method to semilinear partial functional differential equations with infinite delay. The study aims to understand the solution semigroup generated by a particular partial functional differential equation with infinite delay. The paper presents some basic results on existence, uniqueness and properties of integral solutions and then establishes properties of the solution operator in nonlinear case. It utilizes the Crandall and Liggett theorem in order to compute the nonlinear semigroup by an exponential formula.

In this paper, we propose a forward kinematics model with natural coordinates for the Gough–Stewart manipulator and other spatial parallel mechanisms. The prevailing merits of this model are that the constraint equations are either quadratic or linear and the coordinates are fully Cartesian. As a result, the derivative matrix of the constraint equations only consists of linear or constant elements, which shows remarkable advantages in kinematic and dynamic analysis over those built through the rotation matrix, the elements of which often contain quadratic or transcendental functions. Application examples show that the virtues are obvious in the analysis of the kinematics of spatial parallel manipulators, especially for those with six full degrees of freedom (DoFs), including three translational DoFs and three rotational DoFs. In reality, this method is easily understood and will be widely used in engineering applications. [ABSTRACT FROM AUTHOR]

The paper deals with the prediction of coupled sway-roll-yaw motions of a ship with constant forward speed, subject to regular wave force. The governing equations derived in time domain after balancing the hydrodynamic and exciting forces are solved analytically while considering the motion variables, wave frequency and external force are complex quantities. Numerical experiments were carried out for a Panamax container ship under the action of a sinusoidal wave of periodicity 11.2 sec with the variations of speed and wave height. The effect of various parameters on motion responses and system stability is investigated. [ABSTRACT FROM AUTHOR]

The interaction of a buoyancy induced mixed convection flow and a free stream impinging at some angle of incidence on a vertical flat plate with a prescribed surface heat flux is studied in this paper. The similarity equations are numerically solved for some values of the governing parameters. It is found that the buoyancy force and non-orthogonal mechanisms act to either reinforce or oppose one another. The stagnation point (separation point) is shifted at the left or at the right of the origin and it depends upon the balance between obliqueness and thermal effects. [ABSTRACT FROM AUTHOR]

In this paper we describe a new model consisting of N articulated rigid bodies with open chain structure, that move in the combined gravitational field of two mutually attracting massive centers. We derive the general equations of motion of the chain and we study the conditions for the planar motion of the individual centers of mass of the links. [ABSTRACT FROM AUTHOR]

We study the third-order linear difference equation with quasi-differences and its adjoint equation. The main results of the paper describe relationships between the oscillatory and nonoscillatory solutions of both equations. [ABSTRACT FROM AUTHOR]

Very recently we have proposed to use a complex Ginzburg-Landau equation for high contrast inpainting, to restore higher dimensional (volumetric) data (which has applications in frame interpolation), improving sparsely sampled data and to fill in fragmentary surfaces. In this paper we review digital inpainting algorithms and compare their performance with a Ginzburg-Landau inpainting model. For the solution of the Ginzburg-Landau equation we compare the performance of several numerical algorithms. A stability and convergence analysis is given and the consequences for applications to digital inpainting are discussed. [ABSTRACT FROM AUTHOR]

This paper is concerned with the numerical modeling of powder cold compaction process using a density-dependent endochronic plasticity model. Endochronic plasticity theory is developed based on a large strain plasticity to describe the nonlinear behavior of powder material. The elastic response is stated in terms of hypoelastic model and endochronic plasticity constitutive equations are stated in unrotated frame of reference. A trivially incrementally objective integration scheme for rate constitutive equations is established. Algorithmic modulus consistent with numerical integration algorithm of constitutive equations is extracted. It is shown how the endochronic plasticity describes the behavior of powder material from the initial stage of compaction to final stage, in which material behaves as solid metals. It is also shown that some commonly used plasticity models for powder material can be derived as special cases of the proposed endochronic theory. Finally, the numerical schemes are examined for efficiency in the modeling of a plain bush, a rotational-flanged and a shaped tablet powder compaction component. [ABSTRACT FROM AUTHOR]

One of the main research areas in continuum mechanics is constitutive equations. There is no generally accepted viewpoint on or method for this research. Several concepts have appeared, but further studies are still necessary. The paper elucidates some problems and viewpoints of such research [ABSTRACT FROM AUTHOR]

The paper presents a technique for thermoelastoplastic stress–strain analysis of flexible laminated shells of revolution under complex axisymmetric loading. The constitutive deformation equations are used to describe loading along arbitrary plane paths. The problem is solved by the method of successive approximations. A numerical example is given [ABSTRACT FROM AUTHOR]

In this paper, by using of monotone iterative technique, the existence and iterative approximation of the minimax quasi-solutions of the initial value problems for more general first order impulsive differential equations in Banach spaces are investigated. [ABSTRACT FROM AUTHOR]

In this paper, we consider an efficient numerical algorithm for solving the two-dimensional fractional cable equation. The stability and convergency of the numerical scheme are rigorously proved by the Fourier analysis. Then we find that the convergence order is O(τ2+hx4+hy4). Finally, numerical experiments are carried out to verify the accuracy and effectiveness of the new scheme. [ABSTRACT FROM AUTHOR]