Application of an optimized digital correlation method to planar deformation analysis

An optimized digital correlation method (DCM) has been developed to improve previously reported iterative DCMs. The optimized method is shown to be much faster than previous methods while achieving accuracy equivalent to that obtained via simple coarse-fine iterative techniques. The optimized correlation routine employs the Newton-Raphson method with differential corrections to minimize search time. The paper illustrates the optimized DCM and presents a simple flowchart of a practical program. Experiments indicate that the optimized DCM is successful in displacement measurement. In direct strain measurement, however, both DCMs using a coarse-fine search routine and those using the proposed optimized correlation procedure are shown to have large variability in the computed strains.     

Authenticating topological integrity of process plant models through digital watermarking

Process plant models, which feature their intrinsical complex topological relation, are important industrial art works in the field of Computer-Aided Design (CAD). This paper investigates the topology authentication problem for process plant models. Compared with the widely studied watermarking based geometrical information protection and authentication techniques for traditional mechanical CAD drawings, topology authentication is still in its infancy and offers very interesting potentials for improvements. A semi-fragile watermarking based algorithm is proposed to address this interesting issue in this paper. We encode the topological relation among joint plant components into the watermark bits based on the hamming code. A subset of the model’s connection points are selected as mark points for watermark embedding. Then those topology sensitive watermark bits are embedded into selected mark points via bit substitution. Theoretical analysis and experimental results demonstrate that our approach yields a strong ability in detecting and locating malicious topology attacks while achieves robustness against various non-malicious attacks.     

Application of novel atom-type AI topological indices to QSPR studies of alkanes

Atom-type AI topological indices derived from the topological distance sums and vertex degree further are used to describe different structural environment of each atom-type in a molecule. The multiple linear regression based on combined use of the proposed Xu index and AI indices is performed to develop high quality QSPR models for describing six physical properties (the normal boiling points, heats of vaporization, molar volumes, molar refractions, van der Waals' constants, and Pitzer's acentric factors) of alkanes with up to nine carbon atoms. For each of six properties, the correlation coefficient r of the final models is larger than 0.995 and particularly the decrease in the standard error (s) is within the range of 45-86% as compared with the simple linear models with Xu index alone. The agreement between calculated and experimental data is quite good. The results indicate the potential of these indices for application to a wide range of physical properties. The role of each of the molecular size and individual groups in the molecules are illustrated by analyzing the relative or fraction contributions of individual indices. The results indicate that the six physical properties of alkanes are dominated by molecular size while AI indices have smaller influence dependent on the studied properties. Moreover, the studies demonstrate that each atomic group contributes an indefinite value to properties dependent on its structural environment in a molecule or other groups present. The cross-validation using the more general leave-n-out method demonstrates the final models to be highly statistically reliable.     

GIS技术在数字校园建设中的应用

在数字校园建设中应用GIS技术，采用集成二次开发的方法，改善交互界面，实现数据和图形双向查询，将空间信息和属性数据通过空间实体的唯一标识进行关联，创建专题图进行专项统计分析，改变数字校园的固有模式，扩充数字校园功能。     

数字录音技术在电话录音系统中的应用

提出了一种对模拟语音信号进行数字化录音的方法,并将其用于电话录音系统中,实验结果表明,该系统具有录音时间长、音质好、抗干扰性强以及使用方便等优点。     

A computational method for segmenting topological point-sets andapplication to image analysis

We propose a computational method for segmenting topological subdimensional point-sets in scalar images of arbitrary spatial dimensions. The technique is based on calculating the homotopy class defined by the gradient vector in a subdimensional neighborhood around every image point. This neighborhood is defined as the linear envelope spawned over a given subdimensional vector frame. In the simplest case where the rank of this frame is maximal, we obtain a technique for localizing the critical points. We consider, in particular, the important case of frames formed by an arbitrary number of the first largest by absolute value principal directions of the Hessian. The method then segments positive and and negative ridges as well as other types of critical surfaces of different dimensionalities. The signs of the eigenvalues associated to the principal directions provide a natural labeling of the critical subsets. The result, in general, is a constructive definition of a hierarchy of point-sets of different dimensionalities linked by inclusion relations. Because of its explicit computational nature, the method gives a fast way to segment height ridges or edges in different applications. The defined topological point-sets are connected manifolds and, therefore, our method provides a tool for geometrical grouping using only local measurements. We have demonstrated the grouping properties of our construction by presenting two different cases where an extra image coordinate is introduced     

用于QSPR/QSAR的自相关拓扑指数研究

为了能更深入地认识取代芳烃的活性／性质与结构间的关系,建立有意义的构效关系模型,定义表征原子活性／性质的特征值为Ei,由Ei建立取代芳烃的自相关拓扑指数F(t)。其中的F(1)与取代芳烃的8种理化性质、lgKow、急性毒性等均有良好的相关性。本文计算方法简单,所需参数易得,预测结果满意。     

AD9957在射频数字化短波发射机中的应用和仿真分析

首先简要介绍了射频数字化短波发射机的基本原理以及AD9957芯片的主要功能,然后提出了一种利用AD9957芯片来实现射频数字化短波发射机内部数字上变频模块和数/模转换模块的方案,使用System View软件对AD9957在短波发射机中的应用进行仿真分析,最后给出了短波发射机中数字化部分的完整仿真电路图。     

数字图像技术在陶瓷显微图像处理中的应用

以陶瓷显微组织图像为例,运用数字图像技术,结合教学形态学和面向对象思想,对陶瓷显微组织图像进行滤波处理,减少图像分析中的干扰因素和误差以确保获得组元精确的测量结果,再对图像进行区域分割及边缘获取,将具有相近特征的组元分离提取,获得陶瓷各组元的分割图和轮廓图.该方法能快速准确提取陶瓷显微组织图像中的组元,有效地协助研究人员进行陶瓷显微结构定量分析,最终实现陶瓷组元体视学参数的测量.     

Injectivity analysis using interval analysis: Application to structural identifiability

This paper presents a new numerical algorithm based on interval analysis able to prove that a differentiable function is injective. This algorithm also performs a partition of the domain A in subsets A_i where, for all , the cardinality of is constant. In the context of parameter estimation, we show how this algorithm provides an efficient and numerical method to study the structural identifiability of parametric models.     

Critic: a new program for the topological analysis of solid-state electron densities

In this paper we introduce critic, a new program for the topological analysis of the electron densities of crystalline solids. Two different versions of the code are provided, one adapted to the LAPW (Linear Augmented Plane Wave) density calculated by the WIEN2k package and the other to the ab initio Perturbed Ion (aiPI) density calculated with the pi7 code. Using the converged ground state densities, critic can locate their critical points, determine atomic basins and integrate properties within them, and generate several graphical representations which include topological atomic basins and primary bundles, contour maps of ρ and ∇²ρ, vector maps of ∇ρ, chemical graphs, etc.

Program summary

Program title: CRITICCatalogue identifier: AECB_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECB_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: GPL, version 3No. of lines in distributed program, including test data, etc.: 1 206 843No. of bytes in distributed program, including test data, etc.: 12 648 065Distribution format: tar.gzProgramming language: FORTRAN 77 and 90Computer: Any computer capable of compiling FortranOperating system: Unix, GNU/LinuxClassification: 7.3Nature of problem: Topological analysis of the electron density in periodic solids.Solution method: The automatic localization of the electron density critical points is based on a recursive partitioning of the Wigner-Seitz cell into tetrahedra followed by a Newton search from significant points on each tetrahedra. Plotting of and integration on the atomic basins is currently based on a new implementation of Keith's promega algorithm.Running time: Variable, depending on the task. From seconds to a few minutes for the localization of critical points. Hours to days for the determination of the atomic basins shape and properties. Times correspond to a typical 2007 PC.     

Application of wavelet analysis to the study of spatial pattern of morphotectonic lineaments in digital terrain models. A case study

Tectonic faults are often associated with characteristic geomorphological features such as linear valleys, ridgelines and slope breaks that can be identified as lineaments in remotely sensed images or digital terrain models. Lineaments of tectonic origin are often characterised by periodicity and characteristic spatial pattern. Unlike traditional methods of autocorrelation, variogram, lineament density and Fourier analysis, wavelet analysis is capable of capturing and describing both periodicity and spatial pattern of lineaments. In this paper, a case study is shown for the application of wavelet analysis to morphotectonic lineament investigation. Results of wavelet analysis are compared to traditional methods. Although this study involves DEM-derived morphological lineaments, the presented wavelet analysis can be also used for lineaments derived from remotely sensed images. These results hold for this case study and provide a good assessment of the relative abilities of wavelet analysis, but it remains to be seen how effective it is for other data sources, areas and geological terrain.     

多重数字签名技术在办公自动化系统中的应用

随着电子商务的发展,应用需求的复杂化,数字签名技术得到广泛应用,该文介绍了公开密钥加密体制,数字签名技术原理和功能,以及多重数字签名技术,并探讨多重数字签名技术在办公自动化系统中的应用的安全解决方案.     

数字签名技术在Java Applet中的运用

对Java的数字签名技术进行了研究,实现了对JavaApplet小程序的数字签名以及在客户端的认证,给出在JDK1.4的环境下使用Keytool和Policytool工具实现数字签名和认证的具体方法。