Compactness of composition operators on BMOA and VMOA

We give a new and simple compactness condition for composition operators on BMOA,the space of all analytic functions of the bounded mean oscillation on the unit disk.Using our results one may immediately obtain that compactness of a composition operator on BMOA implies its compactness on the Bloch space as well as on the Hardy space.Similar results on VMOA are also given.     

服务管理差距与服务质量差距之间关系模型的研究

在服务质量差距分析模型的基础上,基于服务管理差距和服务质量差距测评体系,运用结构方程建模方法,建立了企业内部服务管理差距与顾客感知服务质量差距之间的关系路径图和关系模型,定量研究了四个服务管理差距对服务质量差距的影响关系、服务管理差距测评指标对相应的四个服务管理差距的影响关系,为顾客感知服务质量差距的测量和评价提供了技术和方法.结合某外语培训学校服务管理实际进行了案例研究,为企业服务质量的诊断和改进提供了科学依据.     

一类卷积型Calderón-Zygmund 算子在端点Triebel-Lizorkin 空间上的有界性

本文主要研究了卷积型Calderón-Zygmund算子在一些端点空间上的有界性.在较弱的正则性条件下,利用原子-分子分解和基于n维Daubechies小波基的算子分析,建立了算子在端点Triebel-Lizorkin空间F0,q1上的有界性.     

An Extension of Set-Valued Contraction Principle for Mappings on a Metric Space with a Graph and Application

In this paper, we obtain an existence theorem for fixed points of contractive set-valued mappings on a metric space endowed with a graph. This theorem unifies and extends several fixed point theorems for mappings on metric spaces and for mappings on metric spaces endowed with a graph. As an application, we obtain a theorem on the convergence of successive approximations for some linear operators on an arbitrary Banach space. This result yields the well-known Kelisky–Rivlin theorem on iterates of the Bernstein operators on C[0,1].     

一类分数次次线性算子及其交换子在齐型空间上的弱Morrey-Herz空间上的有界性

本文研究了一类次线性算子及其交换子在齐型空间上的弱有界性的问题.利用齐型空间的基本性质以及给出的一类次线性算子及其分别与BMO函数,Lipschitz函数生成的交换子在L~p(X)上的弱有界性,证明了其在齐型空间上Morrey-Herz空间中的弱有界性.推广了该类算子在Morrey-Herz空间中的强有界性这一结果.     

Recent progresses in studies on wave-current loads on foundation structure with piles and slab?

The foundation structure with piles and slab is widely used in o?shore wind farm construction in shallow water. Experimental studies on the hydrodynamic loads acting on the piles and slab under irregular waves and currents are summarized with discussion on the e?ects of pile grouping on the wave forces and wave impact loads on the slab locating near the free surface. By applying the theoretical solution of the wave di?racted by the slab and using the Morison equation to evaluate the wave force on the piles, the e?ects of the slab on the wave forces acting on the piles are analyzed. Based on the Reynolds-averaged Navier-Stokes (RANS) equations and the volume of ?uid (VOF) method, a numerical wave basin is developed to simulate the wave-structure interaction. The computed maximum wave force on the foundation structure with piles and slab agrees well with the measured data. The violent deformation, breaking, and run-up of the wave around the structure are presented and discussed. Further work on the turbulent ?ow structures and large deformation of the free surface due to interaction of the waves and foundation structures of o?shore wind farms needs more e?cient approaches for evaluating hydrodynamic loads under the e?ects of nonlinear waves and currents.     

Laplace-Beltrami differentiability of positive definite kernels on the sphere

This contribution gives results on the action of the Laplace-Beltrami derivative on sufficiently smooth kernels on the sphere, those defined by absolutely and uniformly expansions generated by a family of at least continuous functions. Among other things, the results show that convenient Laplace-Beltrami derivatives of positive definite kernels on the sphere are positive definite too. We also include similar results on the action of the Laplace-Beltrami derivative on condensed spherical harmonic expansions.     

Initial boundary value problems for nonlinear dispersive wave equations

In this paper we study initial value boundary problems of two types of nonlinear dispersive wave equations on the half-line and on a finite interval subject to homogeneous Dirichlet boundary conditions. We first prove local well-posedness of the rod equation and of the b-equation for general initial data. Furthermore, we are able to specify conditions on the initial data which on the one hand guarantee global existence and on the other hand produce solutions with a finite life span. In the case of finite time singularities we are able to describe the precise blow-up scenario of breaking waves. Our approach is based on sharp extension results for functions on the half-line or on a finite interval and several symmetry preserving properties of the equations under discussion.     

On polynomial interpolation of two variables

Polynomial interpolation of two variables based on points that are located on multiple circles is studied. First, the poisedness of a Birkhoff interpolation on points that are located on several concentric circles is established. Second, using a factorization method, the poisedness of a Hermite interpolation based on points located on various circles, not necessarily concentric, is established. Even in the case of Lagrange interpolation, this gives many new sets of poised interpolation points.     

中国邮递员问题50年

首先介绍一般邮递员问题, 涉及费用、服务侧、衔接费用、次序等要素. 然后简要综述过去50年来中国邮递员问题、有向图上中国邮递员问题、带风向的邮递员问题、混合图上邮递员问题以及乡村邮递员问题等一般邮递员问题的特殊情况的研究进展, 突出问题的线性规划描述及相应的组合多面体结构, 着重讨论问题的模型、精确算法及其时间复杂度、NP-困难情形下的近似算法及其性能比.     

基础教育发展趋势预测模型研究及应用

以基础教育发展为研究对象 ,在应用新增人口的离散预测模型基础上 ,分别建立了小学和初中招生数、分年级在校生规模、在校生总量、专任教师需求和补充规模的预测模型 ,并结合近几年山东省教育统计结果 ,给出了计算实例 .     

Pseudo-differential Operators,Cubature and Equidistribution on the 3D ball: An Approach Based on Orthonormal Basis Systems

In this paper, the distribution of points on a unit ball in ?³ is investigated. The ansatz is motivated by an approach for point grids on the unit sphere by Cui and Freeden. A formula for a generalized discrepancy is developed, which is then used to check the uniformity of point grids on a ball. The generalized discrepancy originates from an error bound for a quadrature (cubature) rule on the ball with uniform weights. In particular, we discuss the integration of functions from particular Sobolev spaces based on known orthonormal systems on the ball. This includes the introduction of a concept of pseudo-differential operators on the ball. Finally, different point grids are constructed on the ball and are compared by the discrepancy. Furthermore, numerical and graphical comparisons of the grids are presented.     

Mesh-dependent stability for finite element approximations of parabolic equations with mass lumping

In this paper, based on some mesh-dependent estimates on the extreme eigenvalues of a general finite element system defined on a simplicial mesh, novel and sharp bounds on the permissible time step size are derived for the mass lumping finite element approximations of parabolic equations. The bounds are dependent not only on the mesh size but also on the mesh shape. These results provide guidance to the stability of numerical solutions of parabolic problems in relation to the unstructured geometric meshing. Numerical experiments on both uniform meshes and adaptive meshes are presented to validate the theoretical analysis.     

价格政策调整对上市公司影响的实证分析—以中国移动、中国联通香港上市公司为例

基于2000年左右电信管理部门的价格政策调整(下调),中国移动、中国联通香港公司相应的公告,以及关于手机单向收费的传言,实证检测发现,上市时间较短的中国联通比起较长时间上市的中国移动,受价格政策变动的冲击更为显著;对公司本身公告而言,中国移动反应显著而中国联通又反之;对手机单向收费信息期间的检测结果发现,二公司并没有大的异常收益。结论认为上市时间较短的公司股票(中国联通)受行业政策影响较为明显,而较长时间上市的公司股票(中国移动)受公司本身的经营环境、业绩变化的影响较大。     

A mixed integer nonlinear optimization model for gas sale company

In this paper the authors propose an optimisation model, called OMoGaS (Optimisation Modelling for Gas Seller), to assist companies dealing with gas retail commercialisation. The model takes into account the limits on price imposed by law on small consumers as well as the gas company policies in order to explore the commercial consequences of different policies. The GAMS framework is used for the optimisation of the defined MINLP model where the profit function is based on the number of contracts with the final consumers, on the tipology of consumers and on the cost supported to meet the final demand while the constraints include information on a maximum daily gas consumption, on yearly maximum and minimum comsumption in order to avoid penalties and on consumption profiles. A case study is presented.     

基于结构方程模型的市场细分方法应用研究

结构方程模型是当前研究顾客满意和顾客忠诚的主流方法之一,但基于结构方程对顾客满意和顾客忠诚进行市场细分方法的研究却十分缺乏.基于结构方程模型进行市场细分算法的应用研究,并对得出的细分结果进行了解释.     

Influence of observations on the misclassification probability in quadratic discriminant analysis

In this paper it is studied how observations in the training sample affect the misclassification probability of a quadratic discriminant rule. An approach based on partial influence functions is followed. It allows to quantify the effect of observations in the training sample on the performance of the associated classification rule. Focus is on the effect of outliers on the misclassification rate, merely than on the estimates of the parameters of the quadratic discriminant rule. The expression for the partial influence function is then used to construct a diagnostic tool for detecting influential observations. Applications on real data sets are provided.     

Convolution Operators on Expanding Polyhedra: Limits of the Norms of Inverse Operators and Pseudospectra

We consider matrix convolution operators with integrable kernels on expanding polyhedra. We study their connection with convolution operators on the cones at the vertices of polyhedra. We prove that the norm of the inverse operator on a polyhedron tends to the maximum of the norms of the inverse operators on the cones, and the pseudospectrum tends to the union of the corresponding pseudospectra. The study bases on the local method adapted to this kind of problems.     

Gaussian density estimates for solutions of fully coupled forward-backward SDEs

We obtain upper and lower Gaussian density estimates for the laws of each component of the solution to a one-dimensional fully coupled forward-backward SDE. Our approach relies on the link between FBSDEs and quasilinear parabolic PDEs, and is fully based on the use of classical results on PDEs rather than on manipulation of FBSDEs, compared to other papers on this topic. This essentially simplifies the analysis.     

On dynamics of fluids in meteorology

We consider the full Navier-Stokes-Fourier system of equations on an unbounded domain with prescribed nonvanishing boundary conditions for the density and temperature at infinity. The topic of this article continues author’s previous works on existence of the Navier-Stokes-Fourier system on nonsmooth domains. The procedure deeply relies on the techniques developed by Feireisl and others in the series of works on compressible, viscous and heat conducting fluids.