关联图形参数化原理与方法研究

该文对基于关联图形的几何建模参数化原理与方法做了较为系统的研究。文中介绍了关联图形及其相关概念,并在此基础上给出了关联图形的表达、基于关系模型的关联图形的组织、关联图形的联动以及关联图形循环约束问题的解决等基本原理与方法。     

基于超媒体思想的课件系统分析与设计

超媒体技术采用非线性的网状结构组织块状信息，信息关联思想类似于人类的联想记忆结构和思维方式。运用超媒体技术设计教学课件系统，以资源共享为基础，可以灵活的编制教学内容，可在教学过程中进行动态的流程选择。     

基于超图的关联规则可视化方法*

针对传统的关联规则可视化方法缺乏多模式关联规则展现形式、无法展示关联规则的内部信息以及分布情况、属性值重要程度突出不明显等问题,提出了基于超图的关联规则表示方法。首先,基于超图中BF-超边基础理论,给出了BF规则图的定义,并且设计了基于超图的一对一、一对多、多对一、多对多关联规则表示原型;接着,结合“沙漏”结构,设计了基于超图的关联规则可视化布局算法;然后,基于交互理论及其相关技术,设计并实现了交互式关联规则可视化系统。最后,以某省全员人口数据为基础,对算法进行了具体实现和分析。实验结果表明,所提出的可视化形式和已有成果相比具有良好的展现效果。     

基于兴趣度的关联规则挖掘算法

分析了Apriori核心算法，举例说明了其设计思想上的不足，并重新定义了关联规则形式和引进了兴趣度的概念。主要定义了合理的兴趣度，即基于可信度和支持度方差的兴趣度InterestR=[（CR-SRH）／4]^＊（CR＋SRH）,并因此而设计了基于此兴趣度定义的关联规则挖掘算法，并对算法做了适当的分析。     

一种精简的关联规则表示模型

针对关联规则之间存在的冗余性问题,已提出多种精简关联规则模型,但这些模型仍不同程度存在紧致度欠佳、信息丢失或恢复算法复杂的问题.提出了一种含更丰富关联信息的基本关联规则,并以基本关联规则为基础构建无损的精简关联规则集合,它是原始关联规则集合的子集,并能据此完全恢复原始关联规则集合.给出了基本关联规则模型的定义,证明了该精简模型的几个重要性质,并设计了用于挖掘该类规则的挖掘算法.实验表明,基本关联规则模型比现有的关联规则精简模型更加紧致.     

三维CAD环境下的产品数据管理方法

分析三维CAD中基本数据类型，并抽取面向管理的结构化信息；定义了数据问的关系类型及数据生命周期状态；给出数据约束和关联定义．结合CAD数据的生命周期管理，提出关联数据在进行出库、入库、发布等方面的操作时，相关数据进行自动更新的规则．针对CAXA实体设计系统给出管理数据模型，并在SMARTEAM平台上实现．     

基于关联假设的定性组合建模算法

组合建模是基于建模假设和模型片断库，构造定性仿真模型的自动化方法。关联假设是一类模型假设，它既可以用来定义模型片断本身，也可以定义有关模型片断使用的决策信息，将模型库与建模任务联系起来。在知识分类的基础上，该文提出了基于关联假设的模型组合算法，解决了定性仿真模型的构造问题，主要内容包括关联性的表示、关联推理算法及其具体实现，最后给出一个实例。     

CAPP环境下关联规则挖掘技术的应用研究

CAPP系统的数据库中存储了大量的工艺设计资料，如何充分利用这些宝贵的数据和信息是一项非常有意义的研究工作。通过对数据挖掘技术的深入分析，提出了将数据挖掘技术应用于CAPP数据库中，采用关联规则挖掘方法发现基本工艺单元。详细讨论了关联规则的定义和挖掘算法，并给出了具体的挖掘实例，以期为提高CAPP系统的应用效率提供有力的技术支持。     

协同图形编辑系统中并发操作冲突检测的研究

实时协同设计是CSCW应用的重要领域。实时协同设计过程实际上就是并发冲突产生和消解的过程。本文描述协同图形编辑系统中多对象之间的冲突相关定义,提出一种判别并发操作冲突的关联对象冲突检测策略,设计实现相应的冲突检测算法,最后对算法的可行性进行分析。     

数据关联的时序有限自动机模型的建模方法

介绍了一种用时序自动机为数据关联问题建模的方法，对数据关联问题的研究方法做了新的尝试。目前有多种数据关联算法，对这些方法的分析和评价成为急于解决的问题。鉴于观测信息的时序性，该文以有限自动机(FA)为基础，将时间序列引入到有限自动机中，定义了时序有限自动机(TFA)，建立了数据关联(DA)的时序有限自动机模型，用于判断关联算法得到的航迹准确性。     

基于装配层的配合尺寸继承与检验

尺寸信息的表达与处理,直接关系到零件的加工成本以及产品质量,文中分析了装配层尺寸的约束与关联,提出了基于装配层的配合尺寸继承与尺寸检验方法,通过配合的识别,尺寸匹配的自组织,实现了不同零件间的配合尺寸的关联,不仅解决了装配层与零件层间具有直接匹配关系的尺寸合理性差别问题,而且可通过尺寸约束与空间基坐标的传递,实现了配合尺寸的不同标注型式的尺寸继承与检验。     

科技文档中基于约束的平面几何作图

为了提高科技文档中几何作图的效率,在科技文档字处理软件ScienceWord中实现了一种基于约束的平面几何作图系统.为了构建基于约束的作图系统,对约束的相关理论作了研究,讨论了该作图系统的总体设计框架和构建约束作图系统的一般步骤,介绍了系统中建立元素之间约束的用户界面设计.由于系统充分考虑了图形元素之间的几何关系,用户不必求助于别的软件就能在科技文档中高效地绘制出各种复杂的几何图形.     

基于自由度分析的三维几何约束推理求解

三维几何约束求解对于装配设计、装配工艺规划和并行工程等多个领域的研究具有重要意义。以自由度分析为基础，对冗余约束和约束冲突的情况进行判断。采用几何推理的方法，直接从零件上的点、线、面、圆柱面、球面等基本几何元素出发，对这些基本几何元素之间的位置关系进行分析，求解三维几何约束。避免了数值解法中对初始值的依赖和迭代过程的不稳定，提高了三维几何约束求解的速度和稳定性。     

基于活动约束系统的变量化设计

在变量化设计过程中设计对象可以看作是一个几何约束系统,这个系统由几何元素以及作用于几何元素之间的各种约束关系构成。一个复杂的设计对象所对应的几何约束系统往往包含大量几何元素和约束关系,如果不加区别地把所有的几何元素和约束关系纳入变量化求解的范围,则很难满足交互设计的需要。而另一方面几何约束系统又往往是稀疏系统：（1）作用于任一几何元素的约束很少;（2）与任一约束相关的几何元素很少。基于这一事实给出了一种预处理策略从原始几何约束系统中搜索得到一个规模较小的活动约束系统,变量化求解在活动约束系统上进行。该方法已在自行研制的参数化造型系统GEMS5．0中实现。     

Constrained optimization of structures with displacement constraints under various loading conditions

Optimization problems often involve constraints and restrictions which must be considered in order to obtain an optimum result and the resultant solution should not deviate from any of the imposed constraints. These constraints and restrictions are imposed either on the design variables or on the algebraic relations between them. Constraints of allowable stress, minimum size and buckling of members in the absence of allowable displacement constraint are the most important factors in optimization of the cross-sectional area of structural elements. When the allowable displacement constraint is included in the problem as a determinant parameter, since the specifications of most of elements affect the displacement rate, the way of imposing and considering this constraint requires special care. In this research the way of simultaneous imposition of multi displacement constraints for optimum design of truss structures in several load cases is described. In this method various constraints for different load cases are divided into active and passive constraints. The mathematical formulation is based on the classical method of Lagrange Multipliers. Overall, this simple method can be employed along with other constraints such as buckling, allowable stress and minimum size of members for imposing the displacement constraint in various load cases.     

XML结构完整性约束的研究

XML的结构完整性约束用来表示元素之间或路径之间的结构关系,它们在XML查询优化中有着举足轻重的作用。提出了基于元素的结构完整性约束和基于路径的结构完整性约束的概念,定义了排他性包含、必需性包含、路径蕴涵、路径互斥和路径同现的语法和语义,研究了它们的性质以及它们与DTD的关系,在此基础上,给出了将不能用DTD表达的结构完整性约束添加到DTD中的方法。     

RNA Secondary Structure Determination and Representation Based on Constraints Satisfaction

A characteristic common to several problems of molecular biology consists in the satisfaction of a set of constraints coming from different sources of biological knowledge. In this paper, we present two problems that take advantage of a constraint satisfaction formulation. The first problem deals with the representation and visualization of RNA secondary structures. The program RNASEARCH implements an original backtracking based algorithm that evaluates at each node the satisfaction of spatial constraints with the aim at drawing a representation without overlap between secondary structural elements. The second problem addresses the determination of RNA secondary structure in accordance with data. With the program SAPSSARN, the application of classic filtering algorithm is used and we discuss a new search algorithm which computes only so called saturated secondary structures. The main result certainly is the possibility to relax the constraint of the absence of secondary structural elements forbidden in secondary structures computed with dynamic programming based approaches: pseudoknots. Finally, we show how each program takes advantage from the other through a protocol driven by constraints.     

Linear constraint equations for continuous support conditions in finite element analysis

Discretised structural models such as by finite elements imply discretised support conditions. In some cases such as plates on elastic foundation or slabs on large interacting columns an improved formulation of the continuous support conditions is desirable. This can be achieved by means of linear constraint equations. The numerical treatment of linear constraints is discussed for the method of elimination of variables as well as for the method of Lagrange multipliers. Then specific constraint equations for different accuracy requirements are derived, which can be used to constrain rectangular flat shell elements of arbitrary shape functions. These constraints introduce six generalized displacements according to the rigid body motions of the element and transmit the corresponding generalized reactions on the nodal degrees of freedom in a way consistent with distributed reactions. The effect on the strain energy of a square shell element is shown for the different constraint equations. As an application, the linear constraints are used to represent the continuous interaction of columns with the plate in a flat slab structure. Comparison of the finite element solutions with analytical results shows that the derived constraint equations allow a considerably improved formulation of continuous support conditions.     

Recovering three-dimensional shape from a single image of curvedobjects

An algorithm to recover three-dimensional shape, i.e., surface orientation and relative depth from a single segmented image is presented. It is assumed that the scene is composed of opaque regular solid objects bounded by piecewise smooth surfaces with no markings or textures. It is also assumed that the reflectance map R(n ) is known. For the canonical case of Lambertian surfaces illuminated by a point light source, this implies knowing the light-source direction. A variational formulation of line drawing and shading constraints in a common framework is developed. The global constraints are partitioned into constraint sets corresponding to the faces, edges and vertices in the scene. For a face, the constraints are given by Horn's image irradiance equation. A variational formulation of the constraints at an edge both from the known direction of the image curve corresponding to the edge and shading is developed. At a vertex, the constraints are modeled by a system of nonlinear equations. An algorithm is presented to solve this system of constraints