Substitution in Non-wellfounded Syntax with Variable Binding

Inspired from the recent developments in theories of non-wellfounded syntax (coinductively defined languages) and of syntax with binding operators, the structure of algebras of wellfounded and non-wellfounded terms is studied for a very general notion of signature permitting both simple variable binding operators as well as operators of explicit substitution. This is done in an extensional mathematical setting of initial algebras and final coalgebras of endofunctors on a functor category. In the non-wellfounded case, the fundamental operation of substitution is more beneficially defined in terms of primitive corecursion than coiteration.     

基于AST的程序静态分析工具的研究与实现

本文给出了以抽象语法树为基础的软件静态分析工具的体系结构，介绍了该工具中各个模块的设计与实现方法，着重于规则库的设计，以及利用定义好的规则实现自动化的代码检测的过程。     

一种解析GCC抽象语法树的方法

介绍了GCC抽象语法树的结构及在编译过程中的作用。给出解析抽象语法树所使用的词法规则和语法规则,提出了解析GCC抽象语法树的方法。     

基于抽象语法树的数组越界的静态检测方法

针对数组访问越界这一类安全漏洞,以源程序的抽象语法树作为分析对象,提出了一种新的静态解决方案。该方案通过分析数组访问越界安全漏洞的表现,抽象出安全模式,然后根据安全模式以及遍历ast过程中记录的节点属性构建安全规则,最后在安全规则的指导下实现对安全漏洞的检测。     

基于抽象语法树的软件度量工具的设计与实现

为了提高软件质量和控制，改善软件开发过程，文中提出了以抽象语法树为核心的软件度量工具(ASTMT)的体系结构图，介绍了度量工具的功能及特点，详细论述了工具中各个模块的设计与实现方法，着重讨论了抽象语法树的组成及其节点设计。介绍该工具在软件开发中的实际应用，进而验证了工具的实用性与有效性。     

一种基于模板的档案图像压缩新方法

在大容量档案图像数据库中,不仅单页档案图像内部存在数据冗余,而且档案图像页之间存在大量集合冗余.本文提出了基于模板的压缩新方法,通过定义相似图像集合的模板,充分利用图像数据的先验知识,对档案图像的内容进行分析和理解,从图像内和图像间以二维模式压缩图像数据.实验表明,该方法能够大幅提高压缩性能.     

An initial algebra approach to term rewriting systems with variable binders

We present an extension of first-order term rewriting systems. It involves variable binding in the term language. We develop systems called binding term rewriting systems (BTRSs) in a stepwise manner. First we present the term language, then formulate equational logic. Finally, we define rewriting systems. This development is novel because we follow the initial algebra approach in an extended notion of Σ-algebras in various functor categories. These are based on Fiore-Plotkin-Turi’s presheaf semantics of variable binding and Lüth-Ghani’s monadic semantics of term rewriting systems. We characterise the terms, equational logic and rewrite systems for BTRSs as initial algebras in suitable categories. Then, we show an important rewriting property of BTRSs: orthogonal BTRSs are confluent. Moreover, by using the initial algebra semantics, we give a complete characterisation of termination of BTRSs. Finally, we discuss our design choice of BTRSs from a semantic perspective. An erlier version appeared in Proc. Fifth ACM-SIGPLAN International Conference on Principles and Practice of Declarative Programming (PPDP2003).     

一种新的图像边缘检测算法

提出了一种新图像边缘检测算法。与其他方法不同，该文从图像边缘的特性入手来解决边缘检测问题，为此定义了一系列边缘点约束条件作为算法基础，并用集合论的方法解决了这些约束问题，进而建立了整个边缘检测算法。     

一个高效的KNN分类算法

KNN算法是数据挖掘技术中比较常用的分类算法,由于其实现的简单性,在很多领域得到了广泛的应用.但是,当样本容量较大以及特征属性较多时,KNN算法分类的效率就将大大降低.本文将粗糙集理论应用到KNN算法中,实现属性约简,提出了一种新的KNN分类方法,解决了KNN算法分类效率低的缺点,从而可使KNN算法能够得到更广泛的应用.     

A Systematic Approach to Fuzzy Parsing

This paper presents a systematic approach to implementing fuzzy parsers. A fuzzy parser is a form of syntax analyzer that performs analysis on selected portions of its input rather than performing a detailed analysis of a complete source text. Fuzzy parsers are often components of software tools and also of program development environments that extract information from source texts. This paper clarifies the term ‘fuzzy parser’ and introduces an object-oriented framework for implementing reusable and efficient fuzzy parsers. Applications of this framework are described via examples of two software tools. These tools exploit the facilities provided by fuzzy parsers for different purposes, and also for different languages. © 1997 John Wiley & Sons, Ltd.     

A Graph‐based Approach to Continuous Line Illustrations with Variable Levels of Detail

This paper introduces a method for automatically generating continuous line illustrations, drawings consisting of a single line, from a given input image. Our approach begins by inferring a graph from a set of edges extracted from the image in question and obtaining a path that traverses through all edges of the said graph. The resulting path is then subjected to a series of post‐processing operations to transform it into a continuous line drawing. Moreover, our approach allows us to manipulate the amount of detail portrayed in our line illustrations, which is particularly useful for simplifying the overall illustration while still retaining its most significant features. We also present several experimental results to demonstrate that our approach can automatically synthesize continuous line illustrations comparable to those of some contemporary artists.     

A Formal Approach to the Specification of Graphic Object Functions

Graphic objects are an abstract mathematical model for graphic systems. The model is an algebraic approach to represent graphic information, which include modelling operations. This formalism require some method to describe normal graphic procedures, such as changing the object colour or texture mapping, as these procedures are essential to represent graphic processes. This paper extends the theory by introducing the concept of graphic object functions. A graphic object function transforms one graphic object into another, changing its visual appearance or its geometric properties. A formal definition of graphic functions is given, with a characterization of two special kinds of graphic object functions: filters and object transference functions. These two kinds of functions can be used to perform normal graphic operations, such as changing colours, texture mapping or clipping. Equivalence relationships between graphic objects induced by functions are also studied. These relationships establish an hierarchical structure on the graphic object set.     

一种新的Rough集方法在不完备信息系统中的应用

本文提出了一种新的基于相容近似空间的Rough集理论在不完全信息系统中进行知识提取.     

一种基于相似粗糙集技术的案例库维护

最近的研究工作突现了在案例推理过程中案例库维护的重要性,越来越多的人认为基于案例推理系统包含了案例库维护的有关过程(Review和Restore)。案例库维护作为CBR研究的一个分支,已经研究出不同的案例库维护策略,其中一些是限制案例库的规模,由此引发了CBR系统的能力与效率问题。相似粗糙集技术可以有效地利用差别矩阵,通过不同的相似度阈值发现以及处理案例库的冗余,有选择地删除多余的案例;同时案例库的覆盖度不降低,减少了案例适应性修改的代价,从而确保了CBR系统的能力与效率的兼顾。     

基于蚁群优化的多个属性约简的求解方法

属性约简是粗糙集理论研究的一个核心问题,很多情况下多个最小属性约简被期望能帮助用户做出更好的决策。文中提出一种基于蚁群优化的获取多个属性约简的方法。首先,结合蚁群优化方法将属性约简问题转化为受限制满足问题,并提出新的模型R-Graph,进而最小属性约简问题转化为在R-Graph中寻找最低成本路径问题。然后,定义吸收算子删除可辨识矩阵中冗余数据的方法以达到简化搜索空间的目的,并提出一个求解多个属性约简的算法(R-ACO)。最后,对比实验说明该方法在大多数情况下能得到更多的最小属性约简结果,并且算法效率较高。     

A New Approach to Graph Recognition and Applications to Distance-Hereditary Graphs

Algorithms used in data mining and bioinformatics have to deal with huge amount of data efficiently.In many applications,the data are supposed to have explicit or implicit structures.To develop efficient algorithms for such data,we have to propose possible structure models and test if the models are feasible.Hence,it is important to make a compact model for structured data,and enumerate all instances efficiently.There are few graph classes besides trees that can be used for a model.In this paper,we inves...     

电磁炉性能测试的一种新方法

介绍了国家标准对于电磁炉性能测试的要求,以及现有测试方法中存在的问题。利用红外热像仪的原理和特点,提出一种电磁炉性能测试的新方法。     

一种提高神经网络泛化能力的新方法

提出了一种改进神经网络泛化能力的新方法——“缩放法”。这种方法通过对输入向量的缩放处理，来缩小或模糊化训练样本和新的模式之间的差别，从而使神经网络的泛化能力得以提高。文中提出的新算法——α算法，可以找到合适的缩放因子，进而得到泛化能力更强的新网络。一些实验例证了“缩放法”和α算法的有效性，并从理论上对其进行了分析和讨论。实验和分析表明，这种方法简单可靠，对许多神经网络和模式分类问题效果明显。     

基于粗糙集理论的入侵检测新方法

提出了一种高效低负荷的异常检测方法，用于监控进程的非正常行为，该方法借助于粗糙集理论从进程正常运行情况下产生的系统调用序列中提取出一个简单的预测规则模型，能有效地检测了进程的异常运行状态，同其它方法相比，用粗糙集建立正常模型要求的训练数据获取简单，而且得到的模型更适用于在线检测，实验结果表明，该方法的检测效果优于同类的其它方法。     

基于多色集合理论的机械产品概念设计方法研究

介绍了多色集合理论，指出了多色集合为计算机辅助概念设计、信息建模技术及其相关的推理技术提供了强有力的工具，使机械产品概念设计这一难以形式化的设计过程有了建模的可能。给出了基于多色集合理论和功能方法树的机械产品概念设计的知识表达。建立了贴近度函数。给出一个关于方案功能相对需求功能冗余程度的教学模型，通过给定冗余允许值排除不合理方案。提出了基于多色集合理论的机构产品概念设计的设计步骤和实现流程图，为其它机械产品 的概念设计提供帮助。最后以机床设计为实例作了进一步的说明。