基于随机模糊集的不完全信息系统粗集模型

传统的Pawlak粗集理论对处理不完全信息系统具有一定的局限性,研究其相关理论及方法具有重大意义.本文引入随机模糊集概念,首先根据专家的领域知识对不完全信息系统进行模糊值完备化,在对象论域构造以随机模糊集为基础的复合模糊关系,以此作为构造复合近似粗糙集模型的出发点.将Krysckiewez容差关系粗集模型和Stefanowki不对称相似关系粗集模型扩展到模糊领域,并对属性约简的一些重要概念进行模糊集扩展.本文的结果为利用粗糙集理论处理不完全信息系统提供了一种新思路.     

短语结构制导的范畴表达式演算

对于语言表达式的组成成分及它们间的关系的刻画,目前大多数语法研究都着重在句法层面,而本文的范畴表达式演算理论则着重在语义层面。我们首先考察了完全表达式与不完全表达式、句法类型与语义类型、继承、顺序、提取、并列等若干重要的语言现象以及各种语法理论对这些现象的解释,然后提出范畴表达式的形式化定义,分析了句法层面的形式约束对语义层面的内容组织的制导作用,并且用典型的语言例子直观的说明了如何利用短语结构制导,进行范畴表达式的演算。这种机制可形式化、可验证,能很好的捕捉语言的组成成分及它们间的相互关系,揭示一个句子所说的内容。     

一种二叉树性质5的证明方法

二叉树的性质5说明完全二叉树中结点之间的关系可以通过对结点编号的简单算术运算得到,这意味着可以用线性结构表示这种非线性结构。为了明确和深入理解为什么完全二叉树结点之间的关系可以隐藏在线性的结点编号中,提出了一种简明的二叉树性质5的证明方法,并将证明思路应用于完全三叉树和完全m叉树,得到一个关于结点编号表示结点之间关系的一般性结论。     

多变量同时检测新方法的研究

提出了一种新而简单的传感器结构,它来自一个平行板电容器,其中的一块极板被分成了三部分,这三部分分别和另一极板可构成3只电容器,从而可得3个电容值。通过3个电容值与液位、介电常数和倾斜状态之间的关系,推导出了它们之间的理论公式。并通过理论计算的方法分别验证了所获得的理论公式。从结果来看,它是一个简单而实用的方法。     

等价关系约束属性的形式概念分析

为了使用户快速的对感兴趣的概念进行搜索,提出了一种等价关系约束属性的概念分析方法。给出了属性间等价的定义并讨论了相应的性质,在此基础上通过属性等价约束关系得到了一种格结构理论,并处理了它们之间的一些性质。通过一个实际例子,说明了此方法的现实意义。     

嵌段共聚物受限自组装结构的计算机模拟和理论预测

本文简述高分子自组装的几种计算机理论模拟方法.重点叙述用模拟方法去模拟和预测嵌段共聚物受限诱导自组装结构的情况.总结它们在一维、二维以及三维受限条件下自组装的理论预测和模拟的研究成果,并指出了在受限条件下自组装的研究中亟待解决的问题.     

典型柔性铰链的结构参数对其刚度性能影响的研究

柔性铰链是目前被广泛用于微动机器人的主要部件之一,其刚度性能直接影响到微动 机器人的终端定位和操作精度．由于实际需要的多样性和复杂性,使得其实际结构的几何尺 寸不能完全满足传统理论分析的假设条件,因此影响到对其性能的准确分析．本文采用有限 元技术对三种典型柔性铰运动变形的力学机理进行了系统的研究,并与传统理论的分析结果 进行了比较,分析了二者间产生误差的根本原因,并给出其结构参数对刚度性能的影响关系 ．     

离散事件动态系统中的控制综合问题

本文将离散事件动态系统（ＤＥＤＳ）监控方法中的控制综合问题作了系统的分类，得到了六种控制综合问题，并将它们表示成泛函极值问题，讨论了它们的可行解，最优解的存在性，可生解集的结构以及相互之间的关系。     

基于节点约束的球杆系统平衡控制策略研究

研究了节点约束的球杆系统的定点平衡控制问题。根据球的位置,球杆系统分为两种类型的结构模式：普通球杆系统和单摆系统。对两种结构的运动特性以及它们之间的切换进行了分析,使用了基于Lyapunov方法的控制策略来解决节点约束球杆系统的平衡问题。通过理论分析和实验,证明了提出的闭环系统控制策略完全收敛于预期的平衡状态,给出了相应的仿真结果。     

(2+1)维广义Borer-Kaup系统的变量分离解和半包局域结构

基于一个特殊的Painlev啨Bcklund变换和多线性变量分离方法,分析了(2+1)维非线性广义BorerKaup(GBK)系统,求得了该系统具有若干任意函数的变量分离严格解.根据得到的变量分离严格解,并通过选择解中的任意函数,引入恰当的局域函数和多值函数,找到了GBK系统一种新的具有实际物理意义的半包局域相干结构,如海洋表面波,并简要地讨论了这种半包局域相干结构的一些特殊的演化性质.结果表明:这种半包局域相干结构相互作用后,完全保持它们原有的速度、波形和波幅,即它们的演化性质是完全弹性的.     

关系规范化理论在数据库设计中的重要性

关系规范化理论是关系数据库开发与设计的重要部分。关系数据库的设计主要取决于关系模式的设计,关系模式设计的好坏直接影响到数据库设计的成败,而关系规范化理论则是指导关系模式设计的标准。该文通过实例探讨关系规范化理论用于关系数据库设计的方法以及关系数据库规范化的原则。     

Parallel process diagnosis based on qualitative models

This paper presents a method for process diagnosis based on a relational process model. To overcome the exponential complexity of the modelling and diagnostic tasks, three main results are described. First, the modelling complexity is reduced by building the overall system model from subsystem models in a component-oriented way. Second, a solution of the diagnostic problem based on relational algebra is presented and successively improved by exploiting the inherent structure of the diagnostic problem. The third idea is to decompose the diagnostic problem and to solve the resulting subproblems in parallel on a multicomputer system. A communication scheme which ensures the correct solution of the diagnostic problem is given. The theoretical results are illustrated by a diagnostic problem occurring in a power station.     

Handling indefinite and maybe information in logical fuzzy relational databases

In this article, fuzzy set theory uses an extension of the classical logical relational database model. A logical fuzzy relational database model was developed with the aim of manipulating imprecise information and adding deduction capabilities to the database system. The essence of this work is the detailed discussion on fuzzy definite, fuzzy indefinite, and fuzzy maybe information and the development of an information theoretical approach of query evaluation on the logical fuzzy relational database. We define redundancies among fuzzy tuples and the operator of their removal. A complete set of fuzzy relational operations in relational algebra and the calculus of linguistically quantified propositions are included also. © 2004 Wiley Periodicals, Inc.     

多级安全关系数据库管理系统

安全关系数据库是目前广泛应用的数据库之一。本文基于安全管理的角度对安全关系数据库进行了分级管理。通过设计新系统SECBase用来集约的解决数据库内部的响应模块的设计与应用问题,希望为今后的数据库开发提供理论支持。     

一种从不完备关系数据中学习PRM的方法

现有的关系学习研究都是基于完备数据进行的,而现实问题中,数据通常是不完备的.提出一种从不完备关系数据中学习概率关系模型(probabilistic relational models,简称PRMs)的方法——MLTEC(maximum likelihood tree and evolutionary computing method).首先,随机填充不完备关系数据得到完备关系数据.然后从每个随机填充后的数据样本中分别生成最大似然树并作为初始PRM网络,再利用进化过程中最好的网络结构反复修正不完备数据集,最后得到概率关系模型.实验结果显示,MLTEC方法能够从不完备关系数据中学习到较好的概率关系模型.     

The Relational Structure of Belief Networks

This paper demonstrates the relational structure of belief networks by establishing an extended relational data model which can be applied to both belief networks and relational applications. It is demonstrated that a Markov network can be represented as a generalized acyclic join dependency (GAJD) which is equivalent to a set of conflict-free generalized multivalued dependencies (GMVDs). A Markov network can also be characterized by an entropy function, which greatly facilitates the manipulation of GMVDs. These results are extensions of results established in relational theory. It is shown that there exists a complete set of inference rules for the GMVDs. This result is important from a probabilistic perspective. All the above results explicitly demonstrate that there is a unified model for relational database and probabilistic reasoning systems. This is not only important from a theoretical point of view in that one model has been developed for a number of domains, but also from a practical point of view in that one system can be implemented for both domains. This implemented system can take advantage of the performance enhancing techniques developed in both fields. Thereby, this paper serves as a theoretical foundation for harmonizing these two important information domains.     

Fuzzy relational compression

This study concentrates on fuzzy relational calculus regarded as a basis of data compression. In this setting, images are represented as fuzzy relations. We investigate fuzzy relational equations as a basis of image compression. It is shown that both compression and decompression (reconstruction) phases are closely linked with the way in which fuzzy relational equations are being usually set and solved. The theoretical findings encountered in the theory of these equations are easily accommodated as a backbone of the relational compression. The character of the solutions to the equations make them ideal for reconstruction purposes as they specify the extremal elements of the solution set and in such a way help establish some envelopes of the original images under compression. The flexibility of the conceptual and algorithmic framework arising there is also discussed. Numerical examples provide a suitable illustrative material emphasizing the main features of the compression mechanisms.     

抽取XML文档到关系数据库

XML在关系数据库中的存储问题是XML研究领域中的一个重要问题。在总结多种映射方法的基础上，提出了一种方法将多个相似的XML文档进行解析，根据映射关系，生成各自的关系模式，并分析归纳出一个集成的关系模式，然后创建一个关系数据库，并在映射关系的基础上提取并存储XML文档数据到关系数据库。此方法以较为简洁的结构保存了XML文档的数据信息，其最大的特点就是不用考虑文档的模式信息（DTD，XML Schema）。并通过一个具体的实验结果来说明这种方法的有效性。     

A new method for computing fuzzy functional dependencies in relational database systems

In this paper, we present a new method for computing fuzzy functional dependencies between attributes in fuzzy relational database systems. The method is based on the use of fuzzy implications. A literature analysis has shown that there is no algorithm that would enable the identification of attribute relationships in fuzzy relational schemas. This fact was the motive for development a new methodology in the analysis of fuzzy functional dependencies over a given set of attributes. Solving this, not so new problem, is not only research challenge having theoretical importance, but it also has practical significance. Possible applications of the proposed methodology include GIS, data mining, information retrieval, reducing data redundancy in fuzzy relations through implementation of logical database model, estimation of missing values etc.     

Prolog-based meta-rules for relational database representation andmanipulation

A Prolog-based experimental system for relational databases that is not defined from the viewpoint of any specific relational topic is proposed. The idea is that the experimental system can be used in many different contexts such as query optimization, data restructuring and database design. The definition is based entirely on the theoretical foundations of the relational model. The experimental system offers a well-defined environment for studying how other systems can be integrated with relational databases. The use of the experimental system in the context of different approaches to deductive databases is considered