摘要：A new simple linear tracking-differentiator (T-D) is presented. Stability and convergence of the T-D are thoroughly proved, which avoids inconvenience of stability proof for nonlinear T-D with switch function. Through error analysis, the presented T-D can extract differential of any piecewise smooth nonlinear signals to reach a high accuracy. Compared with the nonlinear T-D with switch function, shaking phenomenon is avoided at the switching point of the function. By further modifying the linear T-D, it can effectively restrain differential impulses produced by initial errors of signals or by signals suddenly changing. Finally, analysis of several simulation examples shows the effectiveness of the proposed theory.

摘要：In this paper, the continuously differentiable optimization problem min{f（x） ： x∈Ω}, where Ω ∈ R^n is a nonempty closed convex set, the gradient projection method by Calamai and More （Math. Programming, Vol.39. P.93-116, 1987） is modified by memory gradient to improve the convergence rate of the gradient projection method is considered. The convergence of the new method is analyzed without assuming that the iteration sequence {x^k} of bounded. Moreover, it is shown that, when f（x） is pseudo-convex （quasiconvex） function, this new method has strong convergence results. The numerical results show that the method in this paper is more effective than the gradient projection method.

摘要：Huge calculation burden and difficulty in convergence are the two central conundrums of nonlinear topology optimization(NTO).To this end,a multi-resolution nonlinear topology optimization(MR-NTO)method is proposed based on the multiresolution design strategy(MRDS)and the additive hyperelasticity technique(AHT),taking into account the geometric nonlinearity and material *** MR-NTO strategy is established in the framework of the solid isotropic material with penalization(SIMP)method,while the Neo-Hookean hyperelastic material model characterizes the material *** coarse analysis grid is employed for finite element(FE)calculation,and the fine material grid is applied to describe the material *** alleviate the convergence problem and reduce sensitivity calculation complexity,the software ANSYS coupled with AHT is utilized to perform the nonlinear FE calculation.A strategy for redistributing strain energy is proposed during the sensitivity analysis,i.e.,transforming the strain energy of the analysis element into that of the material element,including Neo-Hooken and second-order Yeoh *** examples highlight three distinct advantages of the proposed method,i.e.,it can(1)significantly improve the computational efficiency,(2)make up for the shortcoming that NTO based on AHT may have difficulty in convergence when solving the NTO problem,especially for 3D problems,(3)successfully cope with high-resolution 3D complex NTO problems on a personal computer.

摘要：In this paper,by combining a second-order sliding mode(SOSM)algorithm with the saturation technique,a novel SOSM control scheme has been *** feature of the proposed SOSM controller lies that there is a saturation function imposed on the sliding variable,which could significantly enlarge the domain of attraction for the closed-loop *** geometric method has been utilized to prove that all the sliding variables will be steered to the origin in a finite ***,the relation between the control parameters and the shape of the phase trajectory has also been ***,the proposed method has been applied to the tracking control problem for a robotic manipulator.

摘要：For classical orthogonal projection methods for large matrix eigenproblems, it may be much more difficult for a Ritz vector to converge than for its corresponding Ritz value when the matrix in question is non-Hermitian. To this end, a class of new refined orthogonal projection methods has been proposed. It is proved that in some sense each refined method is a composite of two classical orthogonal projections, in which each refined approximate eigenvector is obtained by realizing a new one of some Hermitian semipositive definite matrix onto the same subspace. A priori error bounds on the refined approximate eigenvector are established in terms of the sine of acute angle of the normalized eigenvector and the subspace involved. It is shown that the sufficient conditions for convergence of the refined vector and that of the Ritz value are the same, so that the refined methods may be much more efficient than the classical ones.

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摘要：In the pragmatics literature the relationship between mitigation and pragmatic empathy remains largely an underexplored,or even worse,a controversial issue,giving rise to the formulation of divergent views of empathy in *** I treat empathy as a working mechanism providing a general explanation of how mitigation works,Caffi(1999;2007;2013)adopts a“paradox”view on *** purpose of this paper is to track down the sources of divergence by comparing and contrasting our conceptualizations of *** is found that the biggest difference lies in the treatment of ***,although I argue in favor of my empathic view,I see it as complementary,rather than contradictory,to Caffi’s *** relationship between mitigation and politeness is revisited with its implications for teaching pragmatics briefly discussed.

摘要：Chinese Newspaper Media in the Omnimedia Era are faced with opportunities and threats brought by media ecological *** media still have the advantages of circulation and *** combing the basic situation and the main advantage of newspaper media development,this paper summarizes communication practice and future development of newspaper *** is found that newspaper media should build a series of self-controlled new media platforms and integrate ***’s more,based on newspaper-oriented,newspaper media should strengthen the core feature of media and maintain the influence and communication value.

摘要：In this paper, we propose two new explicit Almost Runge-Kutta (ARK) methods, ARK3 (a three stage third order method, i.e., s = p = 3) and ARK34 (a four-stage third-order method, i.e., s = 4, p = 3), for the numerical solution of initial value problems (IVPs). The methods are derived through the application of order and stability conditions normally associated with Runge-Kutta methods;the derived methods are further tested for consistency and stability, a necessary requirement for convergence of any numerical scheme;they are shown to satisfy the criteria for both consistency and stability;hence their convergence is guaranteed. Numerical experiments carried out further justified the efficiency of the methods.

摘要：In this paper, we introduce some new classes of the totally quasi-G-asymptotically nonexpansive mappings and the totally quasi-G-asymptotically nonexpansive semigroups. Then, with the generalized f-projection operator, we prove some strong convergence theorems of a new modified Halpern type hybrid iterative algorithm for the totally quasi-G-asymptotically nonexpansive semigroups in Banach space. The results presented in this paper extend and improve some corresponding ones by many others.