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．     

智能刺绣编程系统IEPS的设计与实现

本文描述了智能刺绣编程系统IEPS的设计原理和实现技术。系统把人工智能和图像处理等技术用于传统的刺绣生产,采用平板扫描仪自动地输入刺绣图案,并解决了自动编针,实现了图案输入、处理、编针、优化和生成刺绣样板的一体化.文中介绍了系统的总体结构,图像处理系统以及编针和优化等实现技术.     

智能刺绣CAD系统的设计与实现

本文描述了智能刺绣ＣＡＤ系统的设计和实现技术。系统把人工智能、图像和图形处理等用于传统的刺绣生产，建立了一套有效的图形生成、编辑和修改等功能，并设计了自动编针，实现了图案输入，处理，编针，优化和生成刺绣样板的一体化，该系统的使用大大地提高了刺绣产品的生产效率和质量。     

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.     

基于二叉树搜索空间缩减的测试数据生成

为了减小适应度函数计算量, 提高测试数据自动生成效率, 提出一种基于二叉树表示的搜索空间数据缩减方法。利用二叉树编码, 记录全空间中的覆盖路径和路径长度; 将目标路径和测试路径长度进行对比, 去除路径长度相差较大的路径; 利用遗传算法生成测试数据并同已有两种方法进行比较。实验结果表明, 在保证软件测试数据正确生成的情况下, 该方法在进化代数和运行时间上有明显优势, 生成测试数据效率高。     

MP-RCP:基于RCP的快速恢复iBGP协议

iBGP传播单条最佳路径机制不能保证路由器获得多样性路径,造成链路瞬时故障场景下连接中断及域间扰动。MP-RCP(MultiPath Route Control Platform)优化路由控制平台RCP以降低会话数量及配置复杂性,利用全局可视路由对每台路由器计算、分发多路径。当路由器检测到最佳路径失效后,将报文封装转发到备份路径中避免连接中断;MP-RCP中将失效检测、处理进行分离以避免瞬时故障引起的频繁收敛,从而降低了域间扰动。通过使用Abilene拓扑以及生成拓扑的实验证明了MP-RCP结构能有效避免转发中断和域间扰动。     

复杂区域刺绣问题的建模与求解

含有孔洞的图案是刺绣中经常遇到的图形。刺绣技术的特殊性要求这种图案的填充必须满足其特有的规则。如何为这种图形构成的复杂区域选择一条正确的填充路径是刺绣CAD系统中的一个重要算法。本文对该问题进行了建模,并提出了一种基于启发式搜索的模型求解方法。该方法在寻找路径的过程中可以满足任意设置出、入口点及针迹方向的问题。经过实验,这种方法可以求得较好的刺绣路径。     

CEIP:用于电脑刺绣的图象预处理系统

本文描述了用于电脑刺绣编程系统的图象预处理系统CEIP的设计方法和实现技术,CEIP系统采用平板扫描仪输入刺绣画稿,经过图象预处理系统的识别和处理,成适合刺绣的画稿,本系统所使用的图象处理算法和技术,明显地提高了刺绣样板的生产效率和绣品质量。     

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。     

智能化电脑刺绣编程环境的设计与实现

电脑刺绣机的发明导致了传统刺绣工业的革命,因此各种电脑刺绣编程(打版)系统应运而生.但是,目前的编程系统均缺少智能,自动化程度低,从而导致产品质量差和制造效率低.为了克服上述缺点,研制了一个电脑刺绣智能集成环境.该系统通过采用人工智能技术、计算机辅助设计以及图像处理技术实现了刺绣图案的自动处理和针法的生成,与目前已有的系统相比,刺绣产品质量、编针的自动化和效率大大提高.另外,还介绍了该系统的结构和主要实现技术.     

Split-path enhanced pipeline scheduling

Software pipelining increases the loop execution throughput by overlapping the execution of successive iterations in a pipelined fashion. For loops with control flows, however, software pipelining is not straightforward because we need to consider the overlap of more than one execution path. Modulo scheduling simply transforms them into straightline loops through if-conversion which, in effect, achieves a fixed, worst-case initiation interval (/spl par/) among all paths. On the other hand, all-path pipelining (APP) and enhanced pipeline scheduling (EPS) can achieve a variable /spl par/ depending on the path that is taken at execution time. Unfortunately, APP concentrates only on the overlap within the same path, entirely losing the overlap between different paths, whereas EPS attempts to overlap all paths together, failing to produce a tight schedule for each individual path, especially when resource constraints are tight. In this paper, we propose a new approach to EPS called split-path EPS (SP-EPS), which first splits each individual path via tail duplication and then performs EPS in a way to guarantee a tight schedule for each path, while producing a competitive cross-path schedule. We also extend SP-EPS to outer loops such that frequent paths that bypass the inner loop are split and then scheduled by SP-EPS. Our experimental results on nontrivial integer benchmarks show that SP-EPS can achieve as much as a geometric mean of 10 percent speedup over EPS when innermost loops are scheduled by SP-EPS, while it can achieve a geometric mean of 11.9 percent speedup when outer loops are also scheduled by SP-EPS.     

基于路径分组与数据相关松弛的软件流水

软件流水是循环调度的重要方法.有分支循环的流水依然是个难题.现有算法可以分为4类:循环线性化、路径分离、整体调度和路径选择.它们都未能和谐地解决两个对立问题:转移时间最小化和最差约束问题.提出了基于路径分组和数据相关松弛的软件流水框架,试图无矛盾地解决上述问题.其主要思想是:(1)路径分组,即按照路径的执行概率和转移概率将路径分组,力求最小化转移时间;(2)数据相关松弛,力求避免最差约束,即当循环有多条路径时,有些相关在循环执行中并不一定有实例,理想的策略是仅当它有实例时才遵守.初步实验和定性分析表明,此     

A mapping-based approach to eliminating self-intersection of offset paths on mesh surfaces for CNC machining

Geometrically, a tool path can be generated by successively offsetting its adjacent path on the surface with a given path interval, which preferably starts from one of the surface boundaries or a primary curve. The key issues involved in offset path planning are the generation of raw offset paths and the elimination of the self-intersection of raw offset paths. Most researches available in this area are focused on how to generate the raw offset paths, however, the latter, especially how to eliminate the self-intersection of the offset paths on mesh surfaces, has not been sufficiently addressed. In this paper, a mapping-based approach to eliminating the self-intersection of offset paths is proposed for the CNC machining of mesh surfaces. The method first flattens the mesh surface onto a predefined plane by using a mesh mapping technique, and then taking the mapping as a guide, the offset paths are also naturally mapped onto the plane, from which those invalid self-intersection loops can be effectively identified and eliminated. To handle the issue of self-intersection for all types of offset path, a notion of local loop is introduced to detect and eliminate the invalid self-intersection loops. After that the planar paths are inversely mapped into the physical space and the final tool paths used for the machining of mesh surface are obtained. Meanwhile, in order to improve the kinematic and dynamic performance of the machine tool when machining along the generated offset paths, a method for rounding the sharp corners of tool paths, which result from the process of eliminating the self-intersection of raw offset paths, is also preliminarily investigated. Finally, the proposed method is validated by the results of simulations and machining experiments.     

三角网格模型的基本群分割

提出一种有效的三角网格模型分割方法。用Dijkstra算法求出三角网格模型上任意给定一个基点到其余顶点的最短路径树;求出该模型对偶图的最大生成树,且对偶图的边与该最短路径树的边不相交;找出该模型上所有既不属于最短路径树也不和最大生成树相交的边,这些边分别与最短路径树组成的最短环集合就是给定基点处的基本群,沿着这些最短环就可以把网格分割成一个拓扑同胚于圆盘的区域。实验结果表明,该分割方法可以快速、有效地实现网格的分割。     

Control Flow Regeneration for Software Pipelined Loops with Conditions

A new intermediate representation for software pipelined loops with conditions is proposed in the paper. The representation allows separation of operations from different paths and their conditional, as well as speculative scheduling, including speculative computation of conditions. An algorithm that transforms the representation into the executable code is presented. The algorithm uses the notion of finite automata to represent the execution of separate paths as threads of control that are canceled or approved by operations that actually compute the conditions. The approach may be used in conjunction with different scheduling techniques to reconstruct the control flow graph from the final schedule directly. It inherently solves the problems of overlapped predicate lifetimes and speculation. The approach provides also a novel formal model for loop execution.     

基于图象分层优化二元树结构表示的图象处理基本算法

在图象分层优化二元树结构表示的基础上,给出了图象分层优化二元树结构表示的图象 处理基本算法:点搜索算法、邻域查找算法及同级灰度查找算法,试验结果表明,该结构表示 比线性四元树结构表示及指针四元树结构表示相应算法查找速度要快.     

Path testing of computer programs with loops using a tool for simple loop patterns

The purpose of this paper is to present a method for testing computer programs with iteration loops. Given such programs, we have shown that for classes of program paths, identified as sequences of simple loop paths, there is a characterizing function called a simple loop pattern. The key idea of simple loop patterns is that these special functions form a base set which can represent any path computation in the given program. A software tool called SILOP has been developed to automatically generate these simple loop patterns, and each corresponding sequence of simple loop paths can be considered as a test case. The tester uses each test case, and with knowledge of the application program, can generate corresponding test data. This paper also presents a method for selecting the specific paths and test data to determine the simple loop pattern reliably. The tester can use this selection method to predict the number of tests required. In order to apply this selection method, the given program must be a linear computer program. The SILOP tool and this test selection method have been applied to commercial software; in this paper, this computational experience is reported and several examples are given to demonstrate the approach.     

轮廓平移无跳刀连接刀路环树优化算法

提出一个无跳刀的轮廓平移刀路轨迹优化算法．根据刀路环之间父环和子环关系,提出“刀路环树”的概念,将加工刀路的一次环切定义为一个“刀路环向量”,并将刀路环的各个属性定义为刀路环向量的分量．根据无跳刀轨迹的要求,针对刀路环树的各个刀路环向量进行遍历,以获得了一个无跳刀的轮廓平移刀路轨迹算法,并通过与其他算法比较,证明该算法无跳刀、无重复切削,并且可以自动执行．     

Computing shortest words via shortest loops on hyperbolic surfaces

Given a loop on a surface, its homotopy class can be specified as a word consisting of letters representing the homotopy group generators. One of the interesting problems is how to compute the shortest word for a given loop. This is an NP-hard problem in general. However, for a closed surface that allows a hyperbolic metric and is equipped with a canonical set of fundamental group generators, the shortest word problem can be reduced to finding the shortest loop that is homotopic to the given loop, which can be solved efficiently. In this paper, we propose an efficient algorithm to compute the shortest words for loops given on triangulated surface meshes. The design of this algorithm is inspired and guided by the work of Dehn and Birman–Series. In support of the shortest word algorithm, we also propose efficient algorithms to compute shortest paths and shortest loops under hyperbolic metrics using a novel technique, called transient embedding, to work with the universal covering space. In addition, we employ several techniques to relieve the numerical errors. Experimental results are given to demonstrate the performance in practice.     

Synthesizing Transformations for Locality Enhancement of Imperfectly-Nested Loop Nests

Linear loop transformations and tiling are known to be very effective for enhancing locality of reference in perfectly-nested loops. However, they cannot be applied directly to imperfectly-nested loops. Some compilers attempt to convert imperfectly-nested loops into perfectly-nested loops by using statement sinking, loop fusion, etc., and then apply locality enhancing transformations to the resulting perfectly-nested loops, but the approaches used are fairly ad hoc and may fail even for simple programs. In this paper, we present a systematic approach for synthesizing transformations to enhance locality in imperfectly-nested loops. The key idea is to embed the iteration space of each statement into a special iteration space called the product space. The product space can be viewed as a perfectly-nested loop nest, so embedding generalizes techniques like statement sinking and loop fusion which are used in ad hoc ways in current compilers to produce perfectly-nested loops from imperfectly-nested ones. In contrast to these ad hoc techniques however, our embeddings are chosen carefully to enhance locality. The product space can itself be transformed to increase locality further, after which fully permutable loops can be tiled. The final code generation step may produce imperfectly-nested loops as output if that is desirable. We present experimental evidence for the effectiveness of this approach, using dense numerical linear algebra benchmarks, relaxation codes, and the tomcatv code from the SPEC benchmarks.