刺绣CAD中一种随机针码的生成算法研究

针对刺绣CAD中的一种随机针码提出了一种新的生成算法。和已有的算法相比，该算法生成的针码间距均匀，针码之间交叉较少，刺绣图案再现了原始图像的特征，达到了较好的刺绣效果。     

Spiral刺绣针法的路径生成算法

Spiral刺绣针法是一种重要的刺绣针法．首先将待刺绣的区域划分成若干能够生成连续螺旋线的环状子区域,然后将这些子区域组织成一个二叉树结构,采用一个递归过程来连接各个子区域内的螺旋线。最终形成Spiral针法路径．文中算法生成的路径能够由内向外以等距的螺旋线填充任意形状多边形的连通域,并且螺旋线的形状与区域的边界相似．实验结果表明,该算法能获得较好的刺绣效果．     

基于函数约束的Bezier曲线在刺绣CAD系统中的应用

曲线造型是刺绣CAD系统的基础，本文归纳分析了该场景下的应用需求。提出采纳Bezier三次有理曲线作为造型曲线，并对曲线段之间在边界条件下产生的“突变问题”提出了一个基于线性函数的方法以约束曲线段之间的突变。该方法已应用到实际系统中，效果很好。     

电脑刺绣CAD系统的设计与实现

介绍了一个新型的电脑刺绣CAD系统，它结合面向对象、图像处理和计算机辅助设计等多种技术设计实现，能有效地解决当前市场上刺绣软件打版效率低，生产的产品质量差等问题。文中具体阐述了该系统的系统结构，以及系统的主要功能和特点，另外还讨论了系统中关键的数据结构，以及一些实现技术和算法。     

智能化电脑刺绣集成环境

将人工智能和图象处理引入传统的刺绣领域,实现了智能化电脑刺绣集成环境。     

新型绣花机花样文件格式的研究与应用

针对DST、DSB和DSZ等主流花样文件格式中数据处理复杂、花样信息少、功能性信息缺乏等不足,自主研发了一种更可靠、方便和智能化的新型绣花机内部花样文件格式（BSB） 。详细分析了BSB花样文件格式的结构和转换实现方法,并完成了全部功能测试。实验证明：BSB花样文件作为绣花机内部花样文件格式性能稳定可靠,通用性好,具有工程应用价值。     

Functional integration in CAD systems

This paper examines the issue of integration in CAD systems and argues that for integration to be effective, it must address the functional aspects of a CAD system. It discusses the need for integrated systems and, within a structural engineering context, identifies several facets of integration that should be targeted. These include 2-D drafting and 3-D modelling, graphical and nongraphical design information, the CAD data structure and its user interface, as well as integration of the drafting function with other engineering applications. Means of achieving these levels of integration are briefly discussed and a prognosis for the future development of integrated systems explored. Particular attention is paid to the emergence (and potential role) of ‘product models’ which seek to encapsulate the full range of data elements required to define completely an engineering artefact.     

基于面向对象的花边CAD系统的设计与具体实现

阐述了一个采用面向对象技术来设计刺绣ＣＡＤ系统的方法。通过对系统的分析,给出了系统的基本设计模型,确定了面向对象技术的基本元素－－对象,并对对象进行了详细设计。文章最后对系统进行了简单评价。     

工业刺绣软件中基于加权网格的字符变形算法

根据作者在大型工业刺绣软件中的实践经验和相关研究,提出了一种基于加权网格的字符变形算法。实验结果表明,这种算法比原有刺绣辅助设计软件更加易于操作和美观。     

Transformative CAD based industrial robot program generation

Industrial robots are widely used in various processes of surface manufacturing, such as spray painting, spray forming, rapid tooling, spray coating, and polishing. Robot programming for these applications is still time consuming and costly. Typical teaching methods are not cost effective and efficient. There are many off-line programming methods developed to reduce the robot programming effort. However, these methods suffer many practical issues, such as cable/hose tangling, robot configuration, collision, and reachability. To solve these problems, this paper discusses a new method to generate robot programs. Since industrial robots have been used in production for decades, there are many robot programs for different parts generated by the robot programmers. These robot programs, which contain not only the robot paths, but also the programmers' knowledge and process parameters, can be transformed to generate new robot programs for similar parts. In this paper, a transformative robot program generation method is developed based on the existing ones in the database. Experiments were performed to validate the developed methodology. The results are very promising in reducing the programming efforts in surface manufacturing.     

刺绣中的形状分割算法

提出一种适用于刺绣CAD系统中Satin针法的形状分割算法.该算法可将任意形状的平面区域分割成若干个条状的子区域,并且使得每个子区域关于它们的形状线大致对称.以一个改进的直骨架为形状分析基础,通过分析修剪后的骨架上的分叉点找出所有可能的分割线,然后优化这些分割线来对区域进行分割.实验结果表明：该算法对边界噪声具有一定的抗干扰能力,能够满足Satin刺绣的要求.     

Machine path generation for the SIS process

Because of the differences in the nature of rapid prototyping (RP) processes, there is no standard machine path code for them. Each RP process, based on its characteristics and requirements, uses the standard CAD file format to extract the required data for the process. Selective inhibition of sintering (SIS) is a new layered fabrication method based on powder sintering. Like other RP systems, SIS needs a specialized machine path generator to create an appropriate machine path file. Machine path (i.e., boundary path and hatch path) should produce the printing pattern that enables the SIS machine user to easily remove the fabricated part from the surrounding material. A new machine path algorithm, which generates appropriate boundary and hatch paths for the SIS process is proposed. The new machine path generator provides the ability to process CAD models of any size and complexity, the ability for machine path verification before sending the file to the SIS machine, and the ability to fix the possible STL files disconnection errors. In this system, very large STL files can be processed in a relatively small computer memory. The system has been successfully tested on STL files as large as 200 MB. The generated path files have been used in fabrication of several parts by the SIS process.     

Manipulation of CAD surface models with haptics based on shape control functions

With traditional two-dimensional based interfaces, many CAD surface models are difficult to design and edit due to their 3D nature. This paper discusses a technique for the deformation of CAD surface models with haptic interaction based on shape control functions. With the technique, designers can use a haptic interface to directly touch a native B-rep CAD model, and deform it in real-time by pushing, pulling and dragging its surfaces in a natural 3D environment. The deformation is governed by shape control functions. By using the shape functions, designers can specify the area of deformation, and also have greater controls on the shape of deformation. This technique is numerically efficient, and can deform complex surface models involving several thousand control points in real-time. The haptic-based deforming approach gives designers greater flexibility for the manipulation of complex CAD surfaces.     

螺旋刺绣路径的连接及优化

首先将刺绣区域划分成拓扑连续的环域,根据环域之间的相互包含关系将它们组织成一个二叉树;然后通过遍历该二叉树来确定各环域的连接顺序,对需要穿越的环域将生成一条纵向连接路径;最后选择各环域的进出点来生成优化的横向连接路径.实验结果表明：生成的路径能满足螺旋刺绣的基本要求和优化要求.     

三维CAD模型检索综述

对三维CAD模型检索研究现状进行了深入和系统的综述。CAD模型检索可划分为两个层次:基于视觉相似性的三维CAD模型检索、面向语义与功能描述的三维CAD模型检索。分别分析了两种检索层次下CAD模型的检索方法。在此基础上总结了三维CAD模型检索评测基准库、评测方法等。最后展望了现有研究中的难点及进一步的研究方向。     

一种用于交互型CAD的内存管理系统设计

交互型CAD系统得频繁的分配与释放内存。频繁的内存分配与释放是降低应用程序性能的重要原因。应用程序以一种默认的方式使用内存,并为不需要的功能而遭受性能的损失。我们开发了一种专用的内存管理系统,改变用来容纳对象的那块内存的分配行为,较好的解决了这个问题,显著的提高了交互型CAD的效率。     

Parallel sample path generation for discrete event systems and the traffic smoothing problem

We review two approaches, the Standard Clock (SC) technique and Augmented System Analysis (ASA), that have been proposed for generating sample paths of Discrete Event Systems (DES) in parallel. These are placed in the unifying framework of the fundamentalsample path constructability problem: for a finite discrete parameter set = {₁, ..., _m }given a sample path under ₁ the problem is to simultaneously construct sample paths under all remaining parameter values. Using the ASA approach we then consider the problem of smoothing arbitrary, generally bursty, and possibly nonstationary traffic processes which are encountered in many applications, especially in the area of flow control for integrated-service, high-speed networks. We derive some basic structural properties of a smoothing scheme known as the Leaky Bucket (LB) mechanism through which it is seen that the variability of a traffic process can be monotonically decreased by decreasing an integer-valued parameter of this scheme. Finally, we show that a sample path under any value of this parameter is constructable with respect to an observed sample path under any other value. Therefore, by controlling this parameter on line, we show how simple iterative optimization schemes can be used to achieve typical design objectives such as keeping both the mean packet delay due to smoothing and the variability of the traffic process low.     

异构CAD系统协同构架研究

针对异构CAD系统间上层操作指令和底层数据结构存在的差异性,在细胞元语义特征造型技术的基础上,提出了一种全新的支持异构CAD系统间同步协同设计的体系结构,并通过一种优先调度机制有效地解决了异构CAD系统间的“写冲突”问题,提高了实时响应性。该思想初步应用在HUSTCAIDS与AutoCAD间的异构协同设计中,证明了其可行性。     

Spiral tool path generation for diamond turning optical freeform surfaces of quasi-revolution

Space Archimedean spiral is defined firstly in this paper. Thereafter, a new spiral tool path generation based on space Archimedean spiral is proposed for diamond turning optical freeform surfaces of quasi-revolution, which is defined as a surface close to some surface of revolution. By projecting the space Archimedean spiral onto the freeform surface along the normal direction of the base surface instead of a fixed direction like traditional method, a quasi-uniform spiral tool path on the freeform surface can be obtained. This method can be used on diamond turning optical freeform surfaces. Finally, two examples are presented to prove its effectiveness and adaptability.     

Automatic generation of path conditions for concurrent timed systems

This paper presents an automatic method for calculating the path condition for programs with real time constraints. We model concurrent systems using timed transition systems and translate them into extended timed automata. Then an acyclic extended timed automaton is constructed and the path condition is calculated backwards over it. This method can be used for semiautomatic verification of a unit of code in isolation, i.e., without providing the exact values of parameters with which it is called. It can also be used for test case generation for real-time systems. Such a symbolic model checking algorithm was implemented previous in the PET system [E. Gunter, D. Peled, Unit checking: Symbolic model checking for a unit of code, Verification: Theory and Practice 2003, Essays Dedicated to Zohar Manna on the Occasion of his 64th Birthday, Lecture Notes in Computer Science, vol. 2772, Springer, 548–567] for untimed systems. Our method can also be used for the automatic generation of test cases for unit testing. The current generalization of the calculation of path condition for the timed case turns out to be quite tricky, since not only the selected path contributes to the path condition, but also timing constraints of alternative choices in the code.