手写体汉字识别问题综论

本文在讨论了人对汉字的认知心理试验研究结果之后,认为人类的汉字识别是经由整字属性及分层结构的多种途径复合而成的。这些途径中的大多数都可以在手写体汉字的机器识别中模仿运用。由此可把汉字的机器识别方法归纳为整模式法和子模式法两个大类,对它们的有利方面和困难方面进行了讨论;对影响其性能的因素进行了分析;对识别率以及它与识别字集大小和后处理等的关系提出了评估的问题。     

改进的GMDH方法及其在参数预报中的应用

本文在综合了ＧＭＤＨ方法中几种有效的改进算法的基础上，进一步研究了变量预选及部分表达式的构成问题，采用最优化方法确定变量最佳组成式并进行变量筛选，由此得到精度更高、稳定性较好的模型，将其应用于聚丙烯熔指数的预报，仿真结果令人满意。     

空泡溃灭水锤的VOF计算方法

空泡溃灭水锤是核电厂冷却循环系统中较常出现的一种严重的水锤事故。空泡的形成和溃灭是复杂的两相、瞬态过程，对于这一现象的分析是相当困难的。作者尝试着把蒸汽泡的边界看成是冷水流动的自由面，在自由面上考虑蒸汽的凝结。对于自由面的ＶＯＦ算法用了ＶＯＦ算法，取得了令人满意的结果，不仅形象地描绘了空泡的形成和溃灭的过程，而且得到了与实验相符的空泡溃灭高压和弥合速度，因此可为管道设计提供理论基础。     

饲料级磷酸氢钙中氟的几种分析方法比较

本文采用茜素络合酮比色法和氟离子选择电极法对饲料磷酸氢钙进行氟的测定实验对比,得出常用的氟离子选择电极法完全可以代替经典的蒸馏比色法的结论。     

SOME NEW ASPECT OF LYAPUNOV TYPE THEOREMS FOR STOCHASTIC DIFFERENCE EQUATIONS WITH CONTINUOUS TIME

Some new Lyapunov type theorems for stochastic difference equations with continuous time are proven. It is shown that these theorems simplify an application of Lyapunov functionals construction method.     

大红山铜矿岩体结构调查分析

大量工程实践已证明岩体结构是控制岩体稳定性的重要影响因素。为此，以大红山铜矿为研究背景，在选定有代表性调查地段的基础上，引入详细观测线法对其岩体结构进行了详细调查与统计。分析结果表明：调查区域内巷道岩体节理裂隙比较密集和发育，主要发育有倾向N53E、走向N37W、倾角53°，倾向W26S、走向N36W、倾角68°；倾向E1S、走向NIE、倾角89°的三组优势结构面，其中优势结构面第二组和第三组构成不稳定块体，并且断层及软弱夹层比较发育，加剧了巷道的破碎程度，对巷道围岩的稳定性有控制作用。最后提出了在巷道施工中密切注意围岩稳定性变化，避免工程事故的发生的建议。     

Optimized Schwarz methods without overlap for highly heterogeneous media

In this paper an original variant of the Schwarz domain decomposition method is introduced for heterogeneous media. This method uses new optimized interface conditions specially designed to take into account the heterogeneity between the sub-domains on each sides of the interfaces. Numerical experiments illustrate the dependency of the proposed method with respect to several parameters, and confirm the robustness and efficiency of this method based on such optimized interface conditions. Several mesh partitions taking into account multiple cross points are considered in these experiments.     

Mortar finite element discretization for the flow in a nonhomogeneous porous medium

Darcy’s equations model the flow of a viscous incompressible fluid in a rigid porous medium. One of the parameters of the system depends on the permeability of the medium and, when this medium is not homogeneous, the variations of the parameter could be very high. To handle this phenomenon, we propose a discretization of the model that relies on the mortar finite element method. Indeed, the idea is to construct a decomposition of the domain such that the permeability is constant on each element of the partition and to use independent meshes on the different subdomains. We perform the a priori and a posteriori analysis of this discretization and present some numerical experiments which are in good coherency with the results of the analysis.     

THE ANALYSIS OF THE SEPARATED LAYERS ALGORITHM BY DOMAIN DECOMPOSITION METHOD

From the principle of of the Domain Decomposition Method (DDM), we analyse the 2nd-order linear elliptic partial differential problems and link the Separated-Layers Algorithm (SLA) with DDM. The mathematical properties of SLA and numerical example are presented to obtain satisfactory computation results. For general linear differential ones, also are the structure of SLA and its characteristics discussed.     

Coupling techniques in boundary-combined methods for solving elliptic problems with singularities

Three coupling strategies in matching the Ritz-Galerkin method and the finite element method are introduced for general elliptic equations, and useful numerical techniques are provided. Numerical experiments have been carried out for solving the typical, singular Motz problem, which shows that optimal convergence rates of numerical solutions can be achieved by using the combined methods and techniques provided in this paper.