An exponentially fitted special second-order finite difference method for solving singular perturbation problems

An exponentially fitted special second-order finite difference method is presented for solving singularly perturbed two-point boundary value problems with the boundary layer at one end (left or right) point. A fitting factor is introduced in a tri-diagonal finite difference scheme and is obtained from the theory of singular perturbations. Thomas Algorithm is used to solve the system and its stability is investigated. To demonstrate the applicability of the method, we have solved several linear and non-linear problems. From the results, it is observed that the present method approximates the exact solution very well.     

New Constructions of Disjoint Distinct Difference Sets

New constructions of regular disjoint distinct difference sets (DDDS) are presented. In particular, multiplicative and additive DDDS are considered.     

现代区域地理学初论

现代区域地理学与传统区别在于加强应用性。它强调人与自然环境相互关系，承认区域性质或功能发现的认识过程，提倡理论与方法的现代化与多样化。     

基于离差最大化原理的灰色综合评判方法及其应用

在灰色综合隶属度评价方法基础上,按照离差最大化原理,提出了一种品种区域试验的新的确定权重的方法.应用这种方法,对2002-2003年度国家黄淮南片小麦冬水组区域试验进行了分析.结果表明,这种分析方法克服了通常专家调查法和层次分析法主观随意性强的缺点,因而其分析结果更加客观、可靠.大面积生产实践也表明该方法具有一定可行性和有效性.     

Sparse generalized Fourier transforms

Block-diagonalization of sparse equivariant discretization matrices is studied. Such matrices typically arise when partial differential equations that evolve in symmetric geometries are discretized via the finite element method or via finite differences. By considering sparse equivariant matrices as equivariant graphs, we identify a condition for when block-diagonalization via a sparse variant of a generalized Fourier transform (GFT) becomes particularly simple and fast. Characterizations for finite element triangulations of a symmetric domain are given, and formulas for assembling the block-diagonalized matrix directly are presented. It is emphasized that the GFT preserves symmetric (Hermitian) properties of an equivariant matrix. By simulating the heat equation at the surface of a sphere discretized by an icosahedral grid, it is demonstrated that the block-diagonalization is beneficial. The gain is significant for a direct method, and modest for an iterative method. A comparison with a block-diagonalization approach based upon the continuous formulation is made. It is found that the sparse GFT method is an appropriate way to discretize the resulting continuous subsystems, since the spectrum and the symmetry are preserved. AMS subject classification (2000)  43A30, 65T99, 20B25     

服务地方经济与社会体现区位优势和特色--高职院校学报发展概览

近年来高职院校学报迅速发展，取得了良好的社会效益，但还存在着诸如竞争力不强、未能体现高职院校特色等问题。因此，高职院校学报应当在谋求自身发展的同时，积极探索高等职业教育与区域经济发展的互动模式，为实现地方经济全面、协调和可持续发展提供参考依据，对区域经济发展起到推动作用，并在此过程中体现自身的特色。     

推进河北省区域创新体系建设的思考

河北省推进区域创新体系建设 ,必须发挥比较优势 ,充分挖掘创新资源的多样性 ,强化企业创新主体地位 ,建立产学研联合的创新支撑体系 ,加强同京津的合作创新 ,建立开放的创新体系 ,实施传统优势产业与高技术产业协调发展的技术创新战略 ,建设具有地方特色的农业创新体系 ,加快科技中介服务体系建设 ,推动全社会加大创新投入 ,全力营造良好的创新环境。     

Analysis of a finite-difference scheme for a singularly perturbed problem with two small parameters

We study a model linear convection-diffusion-reaction problem where both the diffusion term and the convection term are multiplied by small parameters ε_d and ε_c, respectively. Depending on the size of the parameters the solution of the problem may exhibit exponential layers at both end points of the domain. Sharp bounds for the derivatives of the solution are derived using a barrier-function technique. These bounds are applied in the analysis of a simple upwind-difference scheme on Shishkin meshes. This method is established to be almost first-order convergent, independently of the parameters ε_d and ε_c.     

Contractivity and Analyticity in l p of Some Approximation of the Heat Equation

We consider the lumped mass method with piecewise linear finite elements in two dimensions. When the triangulation is of Delaunay type it is known that the discrete scheme satisfies a maximum principle. In this work we pursue the analysis and prove that the discrete semi-group is l ^p contractive in a sector, which implies smoothing effects and provide some resolvent estimates.     

区域技术创新系统评估体系的研究

技术创新对提升企业竞争力、提高综合国力、促进经济增长和国家持续发展非常重要。本在研究了区域经济发展和国家创新系统的相关献基础上，建立了系统、量化的区域技术创新系统评估指标体系，提出了决定区域创新系统技术创新能力的主要因素，并用TOPSIS方法对指标的量化进行了尝试。