ADIF,a FORTRAN IV program for solving the shallow-water equations

A computer program is documented, implementing a linear Alternating Direction Implicit (ADI) method for a limited-area finite difference integration of the shallow-water equations on a β plane. Arbitrarily large time-steps can be used with this method, which is stable unconditionally for the linearized equations. The method also is efficient computationally, as the difference equations are factored into one-dimensional operators which approximately reproduce the original set of equations, and this obviates the necessity for solving a matrix of large bandwidth. A line-printer plot contouring the height field is generated as part of the output. Program options include the determination at each time step of two of the integral invariants of the shallow-water equation. For long-term runs either a dissipative term is provided, or a nonlinear lateral eddy viscosity coefficient of a friction force.     

An interactive FORTRAN 77 program using GKS graphics for 2.5 D modeling of gravity and magnetic data

An interactive 2.5 D gravity and magnetics modeling program has been written for an ICL PERQ 2 workstation using FORTRAN 77 and GKS graphics. All of the available hardware and software input devices are utilized through GKS to produce an easy-to-use menu-driven program. A large number of functions are controlled by the software in order than the user can concentrate on the model. A range of options also are provided for manipulating the observed anomaly. The use of FORTRAN 77 and GKS should make the program easily portable to other computer systems and graphics devices. The modular form of the program should facilitate readily further development including optimization and real time modeling, given a more powerful computer with high-speed graphics.     

Fortran IV program to compute apparent resistivity of a perfectly conducting sphere buried in a half-space

A FORTRAN IV program is presented that computes apparent resistivity of a perfectly conducting sphere buried in a half-space at any depth and for any electrode configuration. The program is based on solution of the problem by the method of images.     

A FORTRAN IV program for interpolating irregularly spaced data using the difference equations for minimum curvature

The interpolation of potential field data is a common problem in geophysics. It is accomplished each time a contour map or profile is drawn. These operations can be difficult and subjective if the data points are irregularly spaced. The method described here produces a “numerical surface”, or grid of values, that approaches the smoothest surface passing through the control points. Such a grid can be contoured automatically by standard routines, producing acceptable results. Alternatively, sections can be drawn through the surface on any azimuth—a more satisfactory procedure for constructing profiles than projecting the data points onto straight lines.     

A simple and fast algorithm for computing exponentials of power series

As was initially shown by Brent, exponentials of truncated power series can be computed using a constant number of polynomial multiplications. This note gives a relatively simple algorithm with a low constant factor.     

A fourier series method for the numerical solution of hyperbolic equations

In this paper a Fourier series technique which reduces the given hyperbolic partial differential equation to a system of ordinary differential equations with one point boundary conditions is presented. The numerical results obtained indicate a considerable saving in time in addition to accuracy since no discretisation errors are incurred in the space variable.     

A simple algorithm for the unique characterization of convex polygons

A simple method for specifying the shape and orientation of a convex polygon is described. The method utilizes eigenvalues and eigenvectors of a “moment of inertia” or mass matrix computed from the nodal coordinates of the polygon. The “shape” is characterized then by the parameter ( , where ξ₁ and ξ₂ are the eigenvalues (ξ₁ ξ₂), and the orientation by the axial direction of the first eigenvector. FORTRAN subroutines are provided for this algorithm.     

一种自适应惯性权重的并行粒子群聚类算法

针对K-means聚类算法和基于遗传（GA）的聚类算法的一些缺点,及求解实优化问题时粒子群算法优于遗传算法这一事实,提出了一种自适应惯性权重的并行粒子群聚类算法。理论分析和实验表明,该算法在收敛速度和收敛精度方面明显优于基于遗传算法的聚类方法。     

分数阶Fourier变换域极值搜索的混沌优化算法研究

正如傅里叶变换采用正弦基,单频信号能够在频域形成峰值,分数阶Fourier变换采用线性调频基,线性调频(LFM)信号能够在分数阶Fourier域上实现聚焦,利用此聚焦性通过搜索峰值可实现LFM信号检测和参数估计.通常采用步进式搜索方法,效率低下.为了克服该缺点,通过对分数阶Fourier域优化问题本质的研究,将混沌优化算法引入到分数阶Fourier域极值搜索中.仿真结果表明:本文的方法优于传统的步进式搜索法.     

量子遗传算法在TSP中的应用

本文提出了一种改进的量子遗传算法,其核心是对量子遗传算法中的量子旋转门的调整策略进行改进。在现有的静态、指数型动态调整策略的基础上提出了基于正弦函数的动态调整策略。文中对旅行商问题（TSP）的仿真实验结果表明：改进后的算法的优化质量和效率都优于遗传算法和一般量子遗传算法。     

On testing orientation data for goodness-of-fit to a von Mises distribution

Statistical testing of two-dimensional orientation data (this is, in which each sample item can be described by a single “azimuth” value) usually assumes that the underlying population has a von Mises distribution. Attention is drawn to a difficulty associated with the fitting of a sample data set to this distribution and FORTRAN IV subroutines to overcome this are presented.     

利用自回归模型的平稳时序数据快速辨识算法

由于自回归模型的参数估计可归结为求解一个线性方程组的问题,故其在平稳时序数据的辨识过程中具有广泛的应用场合。提出了一种基于自回归模型的快速辨识算法,首先,以递推的方式对平稳时序数据自相关函数矩阵的秩的下界值进行估计,然后,以该估计值作为自回归模型的起始阶数对系统进行依次的递阶辨识,最后,基于F检验对相邻阶次的拟合误差的变化趋势进行显著性检验,并以检验结果作为算法的结束条件。新算法在保证较高辨识精度的条件下,其计算效能及辨识精度的稳定性均优于现有的自回归模型辨识算法,实验结果验证了新算法的有效性和先进性。     

A general purpose subroutine for fast fourier transform on a distributed memory parallel machine

One issue which is central in developing a general purpose FFT subroutine on a distributed memory parallel machine is the data distribution. It is possible that different users would like to use the FFT routine with different data distributions. Thus there is a need to design FFT schemes on distributed memory parallel machines which can support a variety of data distributions. In this paper we present an FFT implementation on a distributed memory parallel machine which works for a number of data distributions commonly encountered in scientific applications. We have also addressed the problem of rearranging the data after computing the FFT. We have evaluated the performance of our implementation on a distributed memory parallel machine, the Intel iPSC/860.     

基于二维FFT的图像滤波方法及实现

二维快速傅立叶变换(FFT)在一个传统概念的处理机上实现时,需要芯片具有更多的逻辑资源。本文给出了基于FPGA的自定义处理机(CCM)的二维FFT算法和实现。在CCM的Splash-2平台上实现了二维FFT,计算速度达到180Mflops,最快速度超过Sparc-10工作站的23倍。同时,对于一个N×N图像,这种实现方法可以满足二维FFT所需要的O(N2log2N)次的浮点算术运算。     

形式概念演化生成算法

目前仍然缺乏使用遗传算法构造概念的研究。为此,首先把形式概念的构造问题转换为以形式背景的对象幂集和属性幂集组合空间为搜索空间,以伽罗瓦联系为约束条件的约束最优化问题;然后提出一个新颖的基于遗传演化的概念生成算法——遗传概念生成算法(Geacob)。该算法采用变长结构编码,不仅满足概念形式的表示和演化过程的需要,而且使该算法具有更好的扩展性和通用性。实验表明了该遗传算法求解形式概念的可行性和有效性。     

A fast fingerprint image enhancement algorithm using a parabolic mask

The quality of fingerprint images (FIs) varies depending on the image taking method. The performance of automatic fingerprint recognition systems highly depends on the quality of the fingerprint images. In these images often are distorted areas, where the valleys and ridges are not clear and there are discontinuities at in the ridge flows. To overcome these unwanted defects fingerprint recognition systems employ enhancement algorithms to improve the quality of the images. Following, binarization, feature extraction, and matching algorithms are executed on the enhanced image. In real-time systems, the overall execution time has primary importance and therefore, especially the enhancement algorithm must be fast and effective. In this study, we propose a fast filtering method with a mask of parabolic coefficients based on the directions. The experiments executed on FVC2000 have proved that, the algorithm provides faster and better enhancements from those described in the literature.     

一种应用于电网参数检测的小波消噪交流采样新算法

根据电网参数检测对于交流采样算法的要求,提出了一种新的高精度交流采样算法,对半波傅立叶算法引入小波消噪方法进行信号预处理、运用样条插值法消除非同步采样产生的泄漏误差.仿真结果证明,这种方法与现有交流采样算法相比,具有响应速度快、精确度高的明显优点.