结构参数大修改时的特征值重分析方法

就结构参数发生大修改的情况提出了两种高精度的特征值重分析方法：Ｐａｄｅ　逼近法和推广的Ｋｉｒｓｃｈ混合法．利用这两种方法,计算了一个具有２０２个结点,３５７个梁单元的平面框架的近似特征值．计算结果表明,所提出的方法是结构参数修改时的特征值重分析的有效方法．     

Parallel iteration of the extended backward differentiation formulas

The extended backward differentiation formulas (EBDFs) and theirmodified form (MEBDF) were proposed by Cash in the 1980s forsolving initial value problems (IVPs) for stiff systems of ordinarydifferential equations (ODEs). In a recent performance evaluationof various IVP solvers, including a variable-step-variable-orderimplementation of the MEBDF method by Cash, it turned out thatthe MEBDF code often performs more efficiently than codes likeRADAU5, DASSL and VODE. This motivated us to look at possibleparallel implementations of the MEBDF method. Each MEBDF stepessentially consists of successively solving three non-linearsystems by means of modified Newton iteration using the sameJacobian matrix. In a direct implementation of the MEBDF methodon a parallel computer system, the only scope for (coarse grain)parallelism consists of a number of parallel vector updates.However, all forward–backward substitutions and all right-hand-sideevaluations have to be done in sequence. In this paper, ourstarting point is the original (unmodified) EBDF method. Asa consequence, two different Jacobian matrices are involvedin the modified Newton method, but on a parallel computer system,the effective Jacobian-evaluation and the LU decomposition costsare not increased. Furthermore, we consider the simultaneoussolution, rather than the successive solution, of the threenon-linear systems, so that in each iteration the forward–backwardsubstitutions and the right-hand-side evaluations can be doneconcurrently. A mutual comparison of the performance of theparallel EBDF approach and the MEBDF approach shows that wecan expect a speed-up factor of about 2 on three processors.     

神经网络的自适应删剪学习算法及其应用

在局域卡尔曼滤波算法的基础上,提出了一种自适应删剪学习算法,这一算法的核心是用网络训练结束后得到的局域的误差协方差矩阵测量权重的重要性,通过删除不重要的权重,得到一个紧凑的网络结构.广义异或逻辑函数和手写体数字识别的计算机模拟结果显示该方法是一种有效的网络规模优化算法 关键词： 神经网络 模式识别 广义卡尔曼滤波 删剪     

用金属电子逸出功测定仪做设计性扩展实验的实践

介绍利用金属电子逸出功测定仪研究轴向磁场对自由电子的磁控条件及测定电子比荷,研究真空二极管的伏安特性,研究金属中自由电子的费米－狄拉克能量分布状况等设计性扩展实验的内容和方法。     

Cascade of Random Rotation and Scaling in a Shell Model Intermittent Turbulence

The time behaviors of intermittent turbulence in Gledzer-Ohkitani-Yamada model are investigated. Two kinds of orbits of each shell which is in the inertial range are discussed by portrait analysis in phase space. We find intermittent orbit parts wandering randomly and the directions of unstable quasi-periodic orbit parts of different shells form rotational, reversal and locked cascade of period three with shell number. We calculate the critical scaling of intermittent turbulence and the extended self-similarity of the two parts of orbit and point out that nonlinear scaling in inertial-range is decided by intermittent orbit parts.     

New Exact Solutions for Konopelchenko-Dubrovsky Equation Using an Extended Riccati Equation Rational Expansion Method

Taking the Konopelchenko-Dubrovsky system as a simple example, some families of rational formal hyperbolic function solutions, rational formal triangular periodic solutions, and rational solutions are constructed by using the extended Riccati equation rational expansion method presented by us. The method can also be applied to solve more nonlinear partial differential equation or equations.     

Exact Solutions to Extended Nonlinear Schrödinger Equation in Monomode Optical Fiber

By using the generally projective Riccati equation method, more new exact travelling wave solutions to extended nonlinear Schrödinger equation (NLSE), which describes the femtosecond pulse propagation in monomode optical fiber, are found, which include bright soliton solution, dark soliton solution, new solitary waves, periodic solutions, and rational solutions. The finding of abundant solution structures for extended NLSE helps to study the movement rule of femtosecond pulse propagation in monomode optical fiber.     

文丘里计测量气—固两相流测量的实验和数值计算

给出可用文丘里计测量气-固两相流流量的实验和数值计算的结果,发现了进口与喉口以及喉口与扩张段之间的压差灵敏度是确定载荷比和气体流量的主要参数,压降可被守恒变量和源项模型预测,并与实验值相吻合,文丘里计有可能作为测量气-固混合物在一相流量的一种手段,     

SQL SERVER扩展存储过程实现机制及应用方法初探

介绍SQL Server扩展存储过程的特点及其实现机制,并用一个程序实例阐述了在VC＋＋6．0开发环境下生成SQL Server扩展存储过程动态库框架、编写SQL Server扩展存储过程代码、添加SQL Server扩展存储过程到数据库中及调试SQL Server扩展存储过程的方法和步骤。     

高斯过程下的有限项部分和重对数律

在约束条件下,将标准维纳过程中的有限项部分和的重对数律推广到高斯过程中,获得了渐近不相关条件下,高斯过程中的有限项部分和的重对数律。