Finding Largest Subtrees and Smallest Supertrees

As trees are used in a wide variety of application areas, the comparison of trees arises in many guises. Here we consider two generalizations of classical tree pattern matching, which consists of determining if one tree is isomorphic to a subgraph of another. For the embedding problems of subgraph isomorphism and topological embedding, we present algorithms for determining a largest tree embeddable in two trees T and T' (or a largest subtree) and a smallest tree in which each of T and T' can be embedded (or a smallest supertree). Both subtrees and supertrees can be used in a variety of different applications. For example, when each of the two trees contains partial information about a data set, such as the evolution of a set of species, the subtree or supertree corresponds to a structuring of the data in a manner consistent with both original trees. The size of a subtree or supertree of two trees can also be used to measure the similarity between two arrangements of data, whether images, documents, or RNA secondary structures. In this paper we present a general paradigm for sequential and parallel subtree and supertree algorithms for subgraph isomorphism and topological embedding. Our sequential algorithms run in time O(n ^2.5 log n) and our parallel algorithms in time O(log ³ n) on a randomized crew pram using a polynomial number of processors. In addition, we produce better algorithms for these problems when the underlying trees are ordered, that is, when the children of each node have a left-to-right ordering associated with them. In particular, we obtain O(n ² ) -time sequential algorithms and O(log ³ n) -time deterministic parallel algorithms on crew prams for both embeddings. Received July 17, 1995; revised May 25, 1996, and December 10, 1996.     

基于“JavaBean可视化组件”的开发技术的探究

JavaBean是一种专门为当前软件开发者设计的全新的可视化组件技术,它为软件开发者提供了一种极佳的问题解决方案。该文描述了用JavaBean开发可视化组件的相关技术。通过阐明了可视化编程的原理和过程,引入Java语言的JavaBean技术来进一步说明JavaBean技术在开发可视化组件的机制和优势,尤其是介绍了JavaBean能够被应用程序开发工具侦测其属性和事件的能力。     

Exact observability and exponential stability of infinite-dimensional bilinear systems

This paper deals with exact observability and stability for a class of infinite-dimensional bilinear systems. First we show that the bilinear systems are exactly observable for any positive bounded input signal. Second we prove that given such an input signal the open-loop bilinear systems (or time-varying linear systems) are exponentially stable. A strong motivation of our study comes from chemical engineering processes described by partial differential equations.     

基于最小二乘支持向量机的土壤含水量检测的研究与分析

介绍了一种基于最小二乘支持向量机的方法来实现土壤含水量的检测,实验结果证明该方法有效、可行,并具有一定的实用价值。     

On the mean random inconsistency index of analytic hierarchy process (AHP)

In this paper, we find a closed-form expression for the largest eigenvalue of a three-dimensional random pairwise comparison matrix. This expression can give us all the corresponding distribution moments. In particular, the exact value of the mean and variance of the largest eigenvalue associated a three-dimensional random pairwise comparison matrix are calculated, and are compared with those obtained by others on the topic. For n = 4 to 15, the mean and variance are determined by simulation. The number of simulation runs are determined by taking both the absolute and the relative simulation errors into the consideration.     

Fast and Robust Approximation of Smallest Enclosing Balls in Arbitrary Dimensions

In this paper, an algorithm is introduced that computes an arbitrarily fine approximation of the smallest enclosing ball of a point set in any dimension. This operation is important in, for example, classification, clustering, and data mining. The algorithm is very simple to implement, gives reliable results, and gracefully handles large problem instances in low and high dimensions, as confirmed by both theoretical arguments and empirical evaluation. For example, using a CPU with eight cores, it takes less than two seconds to compute a 1.001‐approximation of the smallest enclosing ball of one million points uniformly distributed in a hypercube in dimension 200. Furthermore, the presented approach extends to a more general class of input objects, such as ball sets.     

Windows脚本部件技术研究与应用

介绍了脚本部件的工作原理、特性以及使用脚本部件的一般步骤 ,指出利用脚本部件创建小巧高效、易于维护和部署的COM部件在工程应用中的意义 ,并给出了利用VisualBasic语言调用脚本部件的应用实例     

基于DC和AC分量的二维数字水印算法

提出一种新的二维数字水印算法,该算法先把原始图像分块DCT,再对水印图像分块DCT,取每一图像块的直流系数和前12个DCT低频交流系数,分别构成水印信号的直流分量和交流分量。利用能量比确定各个子块的直流拉伸因子和交流拉伸因子。水印信号的直、交流分量以不同的能量分别嵌入到原始图像块DCT域的DC分量和AC分量中。实验结果表明,该算法具有良好的不可见性和稳健性。     

嵌入式典型零部件快速设计系统

研究运行于多种三维CAD平台下的嵌入式典型零部件设计系统的组件体系结构,提出基于用户自定义特征的典型零部件数据库设计和模板生成方法,开发了常用的7大类典型零部件设计与校核工具包,实现了CAD平台下典型零部件的模板生成与参数化重构、设计过程导航以及零部件之间基于坐标系的自动装配．最后给出Pro／Engineer2001下嵌入式典型零部件设计系统的运行实例,验证了该系统实现典型零部件从设计到三维造型乃至自动装配过程的一体化、快速化与智能化．     

舰船微电子器件进货检验方案及流程浅析

文章介绍了用于舰船设备的微电子器件现状,包括类型、质量等级、用途等,并简要分析所生产的船用设备中的微电子器件的质量状况,以此为前提并根据船用设备的特点,浅析微电子器件的进货检验方案,并论述进货检验中各个流程的目的,以及改进措施。     

数据结构可视化类库的设计与实现

本工作室开发的数据结构可视化类库(JVDSCL,Visual Data Structures Class Library in Java)将可视化技术引入数据结构类库,实现了数据结构可视化。介绍了对数据结构类的可视化扩充方法,给出了实现各种数据结构可视化布局算法的基本框架。JVDSCL可以应用在程序调试和软件开发,提高软件的可视性、重用性与开发效率。     

理想材料零件CAD/CAM中的数据格式及切片算法研究

为实现由均质材料、复合材料、功能梯度材料和功能细结构构成的理想材料零件的数字化设计制造,从非线性问题线性化角度考虑,针对理想材料零件数字化设计制造中的数据格式和切片算法问题,提出了基于三维几何实体单纯剖分的数据格式。以统一、简便的形式、完整地描述了理想材料零件的几何、拓扑和材料信息;定义了快速制造中必不可少的切片数据格式;在该数据格式的基础上,进行了理想材料零件的均匀切片算法研究,并通过实例验证了该均匀算法。     

Java Web开发中过滤器组件应用及实例解析

Servlet过滤器是Java Web应用中的常用组件,可以拦截请求和响应,以便查看、提取或以某种方式操作客户机和服务器之间交换的数据,具有功能强大、部署简捷的特点。阐述了过滤器的工作原理,组成体系,工作过程,并通过典型实例对过滤器的具体开发和部署进行了详尽说明。     

高校《Flash》中元件与实例的教学设计

随着Flash技术的不断成熟与普及发展,Flash软件已广泛应用到社会的各个领域。很多高校在平面设计、网络技术、机电、动漫、影视等专业都增设了此课程。而元件与实例是Flash软件的重点和难点部分。本文针对高校学生的特点,本着如何让学生真正掌握这门技术,熟练运用软件工具,将成果运用到社会实践中去的目的,根据教学对象、教学内容、教学目标等,探讨讲授这门课程的科学方法和技巧。     

Exact solutions for dynamic analysis of composite plates with distributed piezoelectric layers

Exact solutions are presented for analyzing dynamics of composite plates with piezoelectric layers bonded at the top and the bottom surfaces. The expressions for mechanical displacements, stresses, electric displacements and potential are derived from constitutive relations and field equations for the piezoelectric medium under applied surface traction and electric potential. The procedure is illustrated with a simply supported symmetric cross-ply (0°/90°/0°) graphite–epoxy composite plate covered with piezoelectric material polyvinylidene fluoride (PVDF). Results are in good agreement with those obtained from finite element model.     

电力电子器件发展与展望

本文简单介绍了电力技术的分类,回顾了电力电子技术及其器件的发展过程,说明了现在主流的电力电子器件的工作原理、应用范围及其优缺点,探讨了在本世纪中新型电力电子器件的应用展望。     

表单几何特征组件检测的研究与实现

表单图像变形、倾斜、噪声干扰、打印错位等问题往往使表单的数据域定位不准确,从而导致表单数据域提取失败。针对现有表单处理技术中存在的定位不准的问题提出了通过检测表单的条码、格结构等几何特征组件实现表单数据域的定位,并分别设计滤波器实现了几何特征组件的检测。实验证明了该方法的有效性。     

基于算法框架的可重用部件设计与实现

对算法程序的功能规约进行等价变换,可以自然而且方便地得到求解问题设计思想的精确表达,即循环不变式。抽象算法又可以通过循环不变式获得。对算法程序中的算子进行提取、抽象就可以得到算法框架,而算法框架可以设计出可重用部件。文章通过对数组段极值问题的求解,展示了形式化推导不仅可以得到正确、高效的算法程序,而且具有软件重用的功能,并进一步给出了利用可重用部件求解数组段极值问题的C++实现。     

Swing和Android UI组件的蒙古文扩展研究及实现

由于传统蒙古文显示排版具有特殊性,字符集纳入国际编码标准相对滞后,造成目前主流开发平台上既没有一套完善的支持蒙古文特点的UI组件,也没有形成成熟的蒙古文UI组件扩展方法。通过研究解析Java Swing和Android UI组件的架构,找出一种有效支持蒙古文特点的UI组件扩展方法。使用该方法对Swing和Android UI常用组件进行了扩展。测试结果表明扩展后的组件具有支持国际编码标准及符合蒙古文特点的显示和编辑功能,能满足互联网和移动平台蒙古文应用软件开发的需要。     

Specification and Generation of Environment for Model Checking of Software Components

Model checking of isolated software components is inherently not possible because a component does not form a complete program with an explicit starting point. To overcome this obstacle, it is typically necessary to create an environment of the component which is the intended subject to model checking. We present our approach to automated environment generation that is based on behavior protocols [Plasil, F., and S. Visnovsky, Behavior Protocols for Software Components, IEEE Transactions on Software Engineering, 28(2002)]; to our knowledge, this is the only environment generator designed for model checking of software components. We compare it with the approach taken in the Bandera Environment Generator tool [Tkachuk, O., M. B. Dwyer and C. S. Pasareanu, Automated Environment Generation for Software Model Checking, 18th IEEE International Conference on Automated Software Engineering (ASE03), p. 116, 2003], designed for model checking of sets of Java classes.