HITPARA基于弹性约束的参数化设计系统

文中提出了基于弹性约束的参数化设计系统ＨＩＴＰＡＲＡ,并讨论了其实现方法。ＨＩＴＰＡＲＡ系统可以为用户提供灵活方便的设计环境,很好地解决了隐含约束,约束不足和过约束问题,在参数化设计的算法上取得了一定的突破。     

HITPARA基于弹性约束的参数化设计系统

文中提出了基于弹性约束的参数化设计系统ＨＩＴＰＡＲＡ,并讨论了其实现方法。ＨＩＴＰＡＲＡ系统可以为用户提供灵活方便的设计环境,很好地解决了隐含约束、约束不足和过约束问题,在参数化设计的算法上取得了一定的突破。     

基于约束的参数化设计与建库工具研究

本文提出了基于约束的参数化设计与建库工具的研究思想及实现方法，较为详细地讨论了图形的几何约束信息、结构约束信息，并且研究了图形结构约束与尺寸约束的自动识别、驱动求解等关键技术，采用了双向十字链表存储尺寸链稀疏矩阵并解决了其双向遍历问题，实现了复杂图形的完全参数化尺寸驱动以及多视图的联动，并对约束检测及约束修改提出了合理有效的方法。该方法为产品修改、仿型设计和变量化动态仿真设计提供了有效手段，特别是为系列化产品设计提供了一理想的参数化建库工具。     

几何约束系统中约束的动态管理方法

几何约束系统的建模及求解是参数化技术的核心。但如何对约束进行方便、有效的管理一直是未完全解决的难题，所以在目前所见到的参数化系统中的大多数，难以处理冗余约束、局部过自由度等问题，这严重妨碍了参数化功能的发挥。文中利用自由度分析，非线性代数方程及矩阵理论，提出了一种在几何约束系统中对约束进行动态管理的新方法。并利用这种方法成功解决了冗余约束预报及局部过自由度判断等难题。     

基于约束的参数化设计与建库工具研究

本文提出了基于约束参数化设计与建库工具的研究思想及实现方法，较为详细地讨论了图形的几何约束信息、结构约束信息，并且研究了图形结构约束与尺寸约束的自动识别、驱动求解等关键技术，采用了双向十辽链表存储尺寸链稀疏矩阵并解决了其双向遍布问题，实现了复杂图形的安全参数化尺寸驱动以及多视图的联动、并对约束检测及约束个性提出了合理有效方法。该方法为产品修改、仿型设计用变量化动态仿真设计提供的有效手段，特别是为系     

一种基于功能约束的参数化图形设计方法

本文在现有参数化图形设计方法的基础上述通过对设计过程中功能要求的研究，提出了功能约束的概念，把功能约束引入参数化图形设计过程。在实践的基础邮基于功能约束的参数化图形设计的三种算法，并给出了部分实践的结果。采用本文提出的方法，较好地实现了产品设计中从功能得结构的设计集成，为进一步研究设计集成问题提供了一种尝试。     

一种新的面向参数化绘图的约束管理技术

参数化设计技术是当代ＣＡＤ技术的核心．作为该技术基础的几何约束系统的建模与求解，要求对约束进行方便、有效的管理．为此，本文基于自由度分析、图论、稀疏矩阵及非线性方程等理论，提出了几何约束最大归约理论，实现了几何约束系统的最大分解，并以归约树的形式清晰地表达了系统内在的串、并、耦合机制，并成功地应用于参数化绘图系统中至关重要的约束一致性检查、快速求解等约束管理问题.     

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。     

全参数化设计实现机理及约束可视管理

为了提高设计效率,提出一种全参数化设计方法,系统阐述其实现机理,给出自动施加约束、约束实时显示及约束可视管理算法。并运用AutoCAD二次开发技术,将几何约束求解器CBA和CAD绘图平台有机结合,实现全参数化绘图。     

约束及基于约束的参数化设计

在基于约束的参数化设计中约束的处理十分重要,本文主要分析约束的基本概念、表示、分类及约束的特性。最后提出基于约束的参数化设计的求解过程。     

An object-oriented database system Jasmine: implementation,application, and extension

We have devised an object oriented DBMS called Jasmine for advanced applications. The paper describes the implementation, application and extension of Jasmine in detail. We focus on the impact of the design of its object oriented model and language on database implementation technology. We describe what part of traditional relational database technology we extend to handle object oriented features such as object identifiers, complex objects, class hierarchies, and methods. We introduce nested relations to efficiently store and access clustered complex objects. We use hash based methods to efficiently access nonclustered complex objects. We provide user defined functions directly evaluated on page buffers to efficiently process method invocation. We devise object oriented optimization of queries including class hierarchies, complex objects, and method invocation. We incorporate dedicated object buffering to allow efficient access to objects through object identifiers. We also describe nontrivial applications of Jasmine and discuss the validity of object oriented databases. We focus on a constraint management facility, which can be implemented by taking advantage of the extensibility of Jasmine. The facility includes constraint rules, called design goals, for automatic database population required by engineering applications. Finally, we describe a view facility for schema integration also needed by engineering applications in distributed environments. We focus on how we extend Jasmine to implement the facility     

布局问题约束的分类及表达

对布局问题中的各种约束进行了深入系统的研究和归类,并分析了它们在布局求解中所起作用,特别是将求解策略,规则与方法也看成是一种特殊的约束－导向约束;为基于约束求解算法的柔适性提供了可靠的保证。最后,利用面对对象思想给出了布局约束的表达形式。     

Constant Unary Constraints and Symmetric Real-Weighted Counting Constraint Satisfaction Problems

A unary constraint (on the Boolean domain) is a function from {0,1} to the set of real numbers. A free use of auxiliary unary constraints given besides input instances has proven to be useful in establishing a complete classification of the computational complexity of approximately solving weighted counting Boolean constraint satisfaction problems (or #CSPs). In particular, two special constant unary constraints are a key to an arity reduction of arbitrary constraints, sufficient for the desired classification. In an exact counting model, both constant unary constraints are always assumed to be available since they can be eliminated efficiently using an arbitrary nonempty set of constraints. In contrast, we demonstrate, in an approximate counting model, that at least one of them is efficiently approximated and thus eliminated approximately by a nonempty constraint set. This fact directly leads to an efficient construction of polynomial-time randomized approximation-preserving Turing reductions (or AP-reductions) from #CSPs with designated constraints to any given #CSPs composed of symmetric real-valued constraints of arbitrary arities even in the presence of arbitrary extra unary constraints.     

Integrating Constraints and Concurrent Objects in Musical Applications: A Calculus and its Visual Language

We propose PiCO, a calculus integrating concurrent objects and constraints, as a base for music composition tools. In contrast with calculi such as NiehrenMueller:Free, milner.parrow.ea:calculus-mobile or TyCO vasconcelos:typed-concurrent, both constraints and objects are primitive notions in PiCO. In PiCO a base object model is extended with constraints by orthogonally adding the notion of constraint system found in the -calculus OzCalculus. Concurrent processes make use of a constraint store to synchronize communications either via the ask and tell operations of the constraint model or the standard message-passing mechanism of the object model. A message delegation mechanism built into the calculus allows encoding of general forms of inheritance. This paper includes encodings in PiCO of the concepts of class and sub-class. These allow us to represent complex partially defined objects such as musical structures in a compact way. We illustrate the transparent interaction of constraints and objects by a musical example involving harmonic and temporal relations. The relationship between Cordial, a visual language for music composition applications, and its underlying model PiCO is described.     

尺寸关联约束的识别及求解方法的研究

针对尺寸之间的关联约束，本文首先分析了尺寸链约束的特点，提出了基于尺寸链的尺寸环模型．通过对尺寸和被约束图形对象的识别与理解，研究了尺寸链、尺寸环建立和尺寸环中的尺寸到被约束元素之间的约束关系的映射算法，实现了尺寸关联约束的识别和求解．     

AutoCAD环境下面向对象参数化设计的实现

文章论述了一种面向对象的参数化设计方法。采用基于有向无环超图的约束表示，完整的建立参数化模型，不仅可以表示简单约束关系，还可以方便的表示元素间的双向约束。在交互绘图的过程中获取约束关系并保存，实现参数驱动。利用功能强大的0bjectARX[1]进行AutoCAD上的二次开发，采用面向对象的技术，充分利用0bjectARX的类库，有效发挥其封装性和扩展性，在Windows环境下和VC 结合编程，实现参数化设计。     

Automatic Implication Checking for CHR Constraints

Constraint Handling Rules (CHRs) are a high-level rule-based programming language commonly used to define constraint solvers. We present a method for automatic implication checking between constraints of CHR solvers. Supporting implication is important for implementing extensible solvers and reification, and for building hierarchical CHR constraint solvers. Our method does not copy the entire constraint store, but performs the check in place using a trailing mechanism. The necessary code enhancements can be done by automatic program transformation based on the rules of the solver. We extend our method to work for hierarchically organized modular CHR solvers. We show the soundness of our method and its completeness for a restricted class of canonical solver as well as for specific existing non-canonical CHR solvers. We evaluate our trailing method experimentally by comparing with the copy approach: runtime is almost halved.     

基于图的参数化设计方法

本文描述了一种基于图形数据，利用约束网络来实现约束传递，进而达到参数驱动的参数化设计方法。该方法实现简单，已用于图形建库工具。     

Shape Reconstruction Incorporating Multiple Nonlinear Geometric Constraints

This paper deals with the reconstruction of three-dimensional (3D) geometric shapes based on observed noisy 3D measurements and multiple coupled nonlinear shape constraints. Here a shape could be a complete object, a portion of an object, a part of a building etc. The paper suggests a general incremental framework whereby constraints can be added and integrated in the model reconstruction process, resulting in an optimal trade-off between minimization of the shape fitting error and the constraint tolerances. After defining sets of main constraints for objects containing planar and quadric surfaces, the paper shows that our scheme is well behaved and the approach is valid through application on different real parts. This work is the first to give such a large framework for the integration of numerical geometric relationships in object modeling from range data. The technique is expected to have a great impact in reverse engineering applications and manufactured object modeling where the majority of parts are designed with intended feature relationships.     

Optical Flow Constraints on Deformable Models with Applications to Face Tracking

Optical flow provides a constraint on the motion of a deformable model. We derive and solve a dynamic system incorporating flow as a hard constraint, producing a model-based least-squares optical flow solution. Our solution also ensures the constraint remains satisfied when combined with edge information, which helps combat tracking error accumulation. Constraint enforcement can be relaxed using a Kalman filter, which permits controlled constraint violations based on the noise present in the optical flow information, and enables optical flow and edge information to be combined more robustly and efficiently. We apply this framework to the estimation of face shape and motion using a 3D deformable face model. This model uses a small number of parameters to describe a rich variety of face shapes and facial expressions. We present experiments in extracting the shape and motion of a face from image sequences which validate the accuracy of the method. They also demonstrate that our treatment of optical flow as a hard constraint, as well as our use of a Kalman filter to reconcile these constraints with the uncertainty in the optical flow, are vital for improving the performance of our system.