协同模板中几何约束关系的表示与解释

模板设计标记语言TDML是协同模板中描述设计信息的标记语言，主要用于表示设计对象的部件信息、部件属性信息、部件位置装配关系信息、操作和连接信息等。设计对象是由一系列部件按照一定的约束关系装配而成的，所以约束信息是设计对象重要的结构信息。文章分析并总结了设计对象之间的几何约束及装配位置关系，采用TDML语言加以描述和解释，并用三维建模器ACIS实现了设计部件间位置关系的可视化。     

基于仿真和知识的广义动态约束网络技术

针对并行协同设计中的参数不确定性,将普通的约束网络扩展为广义动态约束网络,以对设计中的不确定性信息进行管理.建立了包含领域级约束和知识级约束的广义动态约束网络模型;提出了基于仿真分析和自适应响应面法的领域级约束建模的有效方法,并提出模糊-粗糙集算法,对仿真结果进行数据挖掘,实现了知识级约束获取;基于模板技术给出了广义动态约束网络中各种约束的统一表示方法;构造了有效的约束冲突求解策略和一致性求解算法,求出一致性设计区间.最后通过设计实例验证了文中方法的有效性.     

复杂网络可视化研究综述

当今万维网、社会关系网等复杂网络的规模迅速发展，一方面导致人们很难用数字和表格来对这些复杂网络进行全局规划和管理，另一方面复杂网络包含了非常丰富的信息资源但都难于被发现。可视化技术提供了有效的方法来理解复杂网络的结构并从中挖掘有效信息。本文全面介绍了复杂网络可视化技术的研究进展，讨论了可视化布点算法和压缩算法，并介绍了若干具有代表性的复杂网络可视化工具、列举了复杂网络可视化技术在相关领域的应用。     

面向网络化协同模板技术的模板设计标记语言

提出了基于XML、面向协同设计的模板设计标记语言———TDML,提炼了TDML的定义及特征,阐述了TDML的语法及语义,并介绍了协同模板可视化设计环境及其包含的有关TDML实现与设计的运行框架;针对该框架下的模板解释器及模板分割与复合、模板结构和参数分离与合并等操作模块进行了描述,给出了模板与可视化造型库的接口.最后以冷冲模与沙发为实例,验证了TDML在协同模板可视化设计系统中的有效性.     

基于Citespace的复杂网络可视化研究图谱

当今万维网、社会网等复杂网络规模的迅猛发展,传统的文字和表格形式已无法满足日益庞大的网络数据的分析和管理,而可视化技术作为一种有效的辅助理解复杂网络的结构并从中挖掘有用信息的方法而得到广泛应用．本文以WebofScience数据库中关于复杂网络可视化的文献为研究对象,利用Citespace软件绘制出该领域的相关知识图谱,研究结果直观的展示了该研究领域主要国家、主要机构、核心期刊;揭示了复杂网络可视化研究领域由理论研究到实证研究、方法探索到实际应用的演进路径;指出可视化算法、可视化工具的研究等为热点,社会网络分析、数据挖掘等研究为前沿,为更快、更好的了解复杂网络可视化研究领域基础及研究进展提供有价值的参考．     

协同设计环境下的版本管理模型

计算机支持协同设计（computer supported cooperative design）是计算机支持协同工作CSCW的一个应用领域,也是CAD技术在未来发展的趋势。由于协同设计中多个人员共同参与设计,必然引进约束来保证协同。需要对设计对象和约束进行协调管理。协同设计中设计对象存在着多个版本。如何保证约束和设计对象版本间的一致对于协同设计的顺利进行具有重要意义。针对这些特点,作者提出了一种基于约束的层次化的管理协同设计版本的模型。     

行业企业联盟CSCW信息平台中的分形网络协作

企业网络协作信息平台是实现行业企业联盟协作活动的基础．分形网络协作遵循大自然的分形法则，可以支持企业网络协同制造的快速动态重构．首先构造了具有自相似、自组织及人机耦合等特性的分形Agent，以有效地表示联盟中各级生产组织单元；运用分形Agent理论以及分形L系统构造了网络协作系统，根据企业级协作系统以及部门级协作系统的结构和工作流管理的自相似性，简化了网络协作问题；最后介绍了分形网络协作的应用实例——CSCW信息平台中的液压成套设备网络协同制造系统．     

基于模糊－粗糙集算法的知识级约束建模

提出了支持复杂产品并行协同设计的广义动态约束网络(GDCN)概念和模型；然后，提出了模糊－粗糙集算法，对仿真结果进行数据挖掘，实现知识级约束获取；最后，开发了基于仿真的知识级约束获取系统，并以某型号V6发动机曲柄连杆机构设计为例，说明了方法的准确性和有效性。     

约束三角剖分研究

约束三角剖分在有限元分析和信息可视化等工程领域具有重要的应用背景,同时是计算几何和计算机辅助几何设计的一个热点问题.本文首先对约束三角剖分进行了分类,然后对其发展及典型算法进行了分析和讨论,最后对约束三角剖分所存在的问题和进一步发展进行了分析.     

基于手势和草图的概念设计协同交互的研究

基于手势和草图的交互模式提供了一种自然和谐的方式来支持概念设计协同操作，促进协同工作系统的发展与应用．基于以用户为中心的设计，比较了不同方式的概念设计过程，提出了基于手势和草图的协同设计方法，进一步讨论了以草图为设计过程中的信息载体，分析了草图信息模型；基于手势操作，提出了协同上下文感知的概念和协同设计上下文描述模型；最后分析并给出面向同步编辑的草图交互设计和双向约束求解方法．所提出的协同设计方法自然简便，提高了设计效率，改善了人机交互方式．     

基于改进成对约束扩充的标签传播聚类算法

针对半监督聚类算法性能受到成对约束数量多寡的限制问题,现有的研究大都依赖于原始成对约束的数量。因此,首先提出了基于灰关联分析的成对约束初始化算法（initialization algorithm of pair constraints based on grey relational analysis,PCIG）。该算法通过均衡接近度计算数据对象间的相似度,并根据相似度的取值来确定可信区间,然后借鉴网络结构初始化方法来扩充数据对象间的成对关系。最后,将其应用于标签传播聚类算法。通过在五个基准数据集上进行实验,基于改进成对约束扩充的标签传播聚类算法与其他方法相比NMI值和ARI值有所提升。实验结果证明了改进成对约束扩充可以有效改善标签传播算法的聚类效果。     

基于装配约束动态管理的虚拟拆卸

装配约束是虚拟拆卸环境下必须考虑的装配体的重要信息，提出虚拟拆卸过程中装配约束的动态管理机制，并实现了基于装配约束导航的虚拟拆卸。装配约束的动态管理包括虚拟环境下装配约束的获取、表达以及拆卸过程中装配约束的动态维护，即装配约束的动态解除和产生，文中用装配约束图表达零件间的装配约束，提出装配约束的间接解除方法，并实现了基于装配约束推理的零件可拆卸方向的推导。最后，通过一个简单装配体的拆卸实例，对文中方法进行了验证。     

New multiresolution modeling techniques in CAD

To apply wavelet transformation to CAD surface model composed of multiple surface patches, an algorithm called wavelet signal separation to preserve geometric constraints during wavelet transformation is proposed. The algorithm divides the B-spline control points into those associated and those unassociated with the geometric constraints. Through preserving the signal information associated with the constraint control points, the geometric constraints can be automatically preserved after wavelet transformation. This paper also briefly investigates two types of the detail feature propagation technique in wavelet-based multiresolution CAD system. One is detail feature motion. The other is detail feature repetition. Finally, a comprehensive example is presented to illustrate the effects of the combination of those techniques.     

Contouring Control for Multi‐Axis Motion Systems With Holonomic Constraints: Theory and Application to a Parallel System

In this paper, the contouring control problem for the constrained multi‐axis motion system is studied. The method of equivalent errors, previously proposed for unconstrained motion systems, is generalized to the system with holonomic constraints. It is shown that the method can be applied to the constrained system provided that the constraints satisfy a proper condition. Because of the constraints, the states in the control law are not completely independent. The unavailable states can be estimated using linear approximation from the constraint equations. As an illustrative example, the proposed method is applied to a parallel motion system with complicated dynamics. A contouring controller is designed using the method of equivalent errors incorporated with integral sliding mode control. Simulation results for contouring circular, elliptic, and square paths verify the effectiveness of the proposed method.     

基于成对约束的半监督凝聚层次聚类算法

对于所提出的建立在成对约束基础之上的半监督凝聚层次聚类算法,对聚类簇进行半监督处理的最主要目的在于借助于对样本监督信息的合理应用,达到提高样本在无监督状态下学习性能的目标.在现阶段的技术条件支持下,以半监督聚类分析为核心,建立在must link以及cannot link基础之上的约束关系被广泛地应用于样本聚类分析的过程当中.从这一角度上来说,为了使聚类簇与聚类簇之间的距离关系表述更加的真实与精确,就要求通过对成对约束关系的综合应用,实现对聚类簇距离的有效调整与优化.     

Autonomous scale control of multiagent formations with only shape constraints

This paper considers a novel problem of how to choose an appropriate geometry for a group of agents with only shape constraints but with a flexible scale. Instead of assigning the formation system with a specific geometry, here, the desired geometry is only characterized by its shape without any location, rotation, and most importantly, scale constraints. Optimal rigid transformation between two different geometries is discussed with especial focus on the scaling operation, and the cooperative performance of the system is evaluated by what we call the geometries' degrees of similarity with respect to the desired shape during the entire convergence process. The design of the scale when measuring the degree of similarity is discussed from constant value and time‐varying function perspectives, respectively. Fixed structured nonlinear control laws that are functions on the scale and the relative positions of agents are developed to guarantee the exponential convergence of the system to the assigned shape. Our research is originated from a three‐agent formation system and is further extended to multiple (n > 3) agents by defining a triangular complement graph. Simulations demonstrate that a formation system with the time‐varying scale function outperforms the one with an arbitrary constant scale, and the relationship between underlying topology and the system performance is further discussed according to the simulation observations. Moveover, the control scheme is applied to bearing‐only sensor–target localization to show its application potentials. Copyright © 2012 John Wiley & Sons, Ltd.     

Making constraint solvers more usable: overconstraint problem

The richness and expressive power of geometric constraints causes unintended ambiguities and inconsistencies during their solution or realization. For example, geometric constraint problems may turn out to be overconstrained requiring the user to delete one or more of the input constraints, and the solutions must then be dynamically updated. Without proper guidance by the constraint solver, the user must have profound insight into the mathematical nature of constraint systems and understand the internals of the solver algorithm. But a general user is most likely unfamiliar with those problems, so that the required interaction with the constraint solver may well be beyond the user's ability. In this paper, we present strategies and techniques to empower the user to deal effectively with the overconstraint problem while not requiring him or her to become an expert in the mathematics of constraint solving.We formulate this problem as a series of formal requirements that gel with other essentials of constraint solvers. We then give algorithmic solutions that are both general and efficient (running time typically linear in the number of relevant constraints).     

Revisiting decomposition analysis of geometric constraint graphs

Geometric problems defined by constraints can be represented by geometric constraint graphs whose nodes are geometric elements and whose arcs represent geometric constraints. Reduction and decomposition are techniques commonly used to analyze geometric constraint graphs in geometric constraint solving.In this paper we first introduce the concept of deficit of a constraint graph. Then we give a new formalization of the decomposition algorithm due to Owen. This new formalization is based on preserving the deficit rather than on computing triconnected components of the graph and is simpler. Finally we apply tree decompositions to prove that the class of problems solved by the formalizations studied here and other formalizations reported in the literature is the same.