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1.
潘卫平  樊治平  黄敏 《控制与决策》2022,37(5):1211-1219
针对矩形件无约束二维板材剪切排样问题,提出一种新的4块排样方式及其生成算法.该排样方式将板材划分成4个块,对每个块,按照递归方式进行排样.选择一行同种矩形件放置在块的左下角,沿着这行矩形件的上边界和右边界将该块剩余部分划分成两个更小的子块以待进一步递归考察.首先,构造动态规划算法一次性生成所有可能尺寸的块中矩形件的递归排样方式;然后,采用隐式枚举算法确定板材的最优4块划分,得到矩形件在板材上的最优4块排样方式.采用文献基准例题和符合实际情况的随机例题,将所提出算法与几种典型的文献算法进行对比,实验结果表明所提出算法时间复杂度在低于或等于文献算法的前提下,排样方式价值比文献算法高.  相似文献   

2.
提出一种快速求解测地线的算法。以此算法为基础,将Voronoi图区域划分思想推广到二维黎曼流形。采用递归方法解决了包含孤岛的自由曲面区域划分,实现了数控加工环切轨迹规划计算,并通过实例验证了该算法的正确性。  相似文献   

3.
改进的Knockout自然景物提取算法   总被引:1,自引:1,他引:0       下载免费PDF全文
窦燕  肖凤  孔令富  冯丙春 《计算机工程》2009,35(14):212-214
针对Knockout算法中颜色估计模型只适用于光滑图像的问题,提出一种新的颜色估计模型。采用区域生长法将未知区域划分为若干个子区域,以距离每一个子区域最近的前景和背景轮廓线上的点为中心做矩形块,分别计算2个矩形块内前景和背景像素点的颜色加权平均值,将其作为该子区域的前景和背景颜色分量。实验结果表明,改进后的颜色估计模型在图像边缘附近颜色相差较大的自然景物提取中有较好表现。  相似文献   

4.
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.  相似文献   

5.
针对二维矩形Packing问题,提出了一种沿阶梯线轮廓进行布局矩形的启发式算法.该算法基于"阶梯式堆码"的启发式规则,能够快速地对矩形块进行紧靠布局.为避免算法陷入局部最优,算法采用随机回溯策略在选择矩形和阶位上扩大搜索范围.结果表明,算法对于浪费面积为零的矩形全Packing问题,能够在极短的时间内找到最优解,同时它也可以很好地求解非零浪费问题.采用国际公认的两个算例进行测试,证明文中算法是非常高效的.  相似文献   

6.
机器人全覆盖最优路径规划的改进遗传算法   总被引:2,自引:0,他引:2       下载免费PDF全文
全区域覆盖是一种特殊的路径规划,要求遍历环境中所有的可达区域。目前已经提的许多算法,如模板算法、分块算法等,都只能保证覆盖所有的区域,对于寻找全局最优解却无能为力。提出了一种基于遗传算法的全区域覆盖算法,结合分块算法和模板算法的优点。先采用矩形分解法将环境划分成若干个相邻的子模块,并为每一个子模块选用相应的模板,从而生成覆盖路径,然后采用遗传算法找出最优的路径。算法在虚拟环境中进行了实验,实验结果证明了其可行性和有效性。  相似文献   

7.
介绍了一种新的非参数回归RBF神经网络学习算法,该算法将RBF神经网络与回归树结合起来使用。回归树的基本思想是通过递归分割将输入空间划分为两部分,对函数进行逼近。由于每一次划分都与轴平行,因此可以用输入分向量满足的不等式来描述每一次划分,从而输入空间就变成了一个用超矩形构成的回归树(二叉树)。回归树的结点可以很容易地转换为径向基函数,通过对回归树结点的访问,可以选择出使网络达到最优的基函数集,形成最终的网络。该算法可以应用到函数逼近、图像处理等各方面。  相似文献   

8.
基于递归的二值图像连通域像素标记算法   总被引:19,自引:1,他引:19  
在研究以前二值图像连通算法的基础上,提出了一种基于递归方法的二值图像连通域像素标记算法。通过对二值图像的扫描和分析可得到二值图像中的连通域划分和连通域的数目。算法主要包括两个步骤:对输入的二值图像进行一次扫描,得到所有目标像素的连通域划分和标记的等价对表;利用递归对等价对表进行分析,得到正确的连通标记划分和连通区域数目。实验结果表明,该算法对于任意复杂形状、任意数目(小于1 000)的连通区域都能正确检测。  相似文献   

9.
对基于facet模型的表面检测的加速技术研究   总被引:2,自引:0,他引:2       下载免费PDF全文
针对基于facet模型的亚体素表面检测算法计算量大的问题,提出将3维facet模型的可分滤波器递归算法与感兴趣区域加速策略相结合的加速方案。可分滤波器递归算法通过在离散正交基下将3维卷积转换为3个1维卷积并使1维卷积递归执行,使计算量与卷积核大小无关,大大节省了计算时间。采用增量算法解决了可分滤波器递归算法内存耗费量大的问题。感兴趣区域加速策略采用图像分割后提取目标的分段包围盒作为有效区域,从而大幅缩减待处理数据量。实验结果表明本文加速方案在保持原始算法精度的同时,能取得很好的加速效果。  相似文献   

10.
本文研究了分块区域p-覆盖的有向传感网节点调度问题,并提出了一种有效延长网络生存时间的节点调度方案。将区域划分为拥有不同监测需求的子区域,从有向传感器节点感知模型出发,设计了基于网格划分的节点感知范围度量方法,并在此基础上提出了分布式分区域节点调度算法DSSA( Distributed Subarea Sensor-schedule Algorithm),该算法是一个选取最少数量的节点去对每一个子区域进行p-覆盖的分布式贪心算法。算法同时还考虑了整体网络的连通。通过仿真深入评估了DSSA算法的性能。对比实验结果表明,DSSA算法可以显著延长网络生存时间。  相似文献   

11.
In late 1979 a two phase heuristic algorithm employing dynamic programming was presented by Steudel for solving the two-dimensional cutting stock problem where all the small rectangles were of the same dimensions, but withour any restrictions that the cutting be performed in a purely “guillotine” fashion. The algorithm was applied to solving the common problem of loading rectangular items of size l by w on a rectangular pallet of size L and W so as to maximize the number of items per layer on the pallet deckboard. In this paper, a new three-phase heuristic is presented which extends the 1979 recursive procedure and evaluates the option of stacking items on their end and/or side surface within the best loading pattern of bottom-stacked items. The resulting pattern is then projected into the third dimension to generate the total “cubic” pallet load. Computation results show that end and/or side stacking (when applicable) can yield average improvements in the range of 5% in items per pallet load.  相似文献   

12.
IPLS is an interactive computerized system developed in 1982 to assist the U.S. Air Force with pallet loading. It uses a dynamic programming based heuristic to solve the two-dimensional problem of loading a rectangular pallet from a set of n rectangular boxes so as to maximize the area covered. Micro-IPLS is a version of IPLS that has been developed recently using Apple Fortran on an Apple II+ microcomputer with 64k. This paper discusses the underlying heuristic used by Micro-IPLS and compares its performance to the results obtained by the latest version of IPLS.  相似文献   

13.
Mathematical models for the problem of loading rectangular boxes into containers, trucks or railway cars have been proposed in the literature, however, there is a lack of studies which consider realistic constraints that often arise in practice. In this paper, we present mixed integer linear programming models for the container loading problem that consider the vertical and horizontal stability of the cargo and the load bearing strength of the cargo (including fragility). The models can also be used for loading rectangular boxes on pallets where the boxes do not need to be arranged in horizontal layers on the pallet. A comprehensive performance analysis using optimization software with 100s of randomly generated instances is presented. The computational results validate the models and show that they are able to handle only problems of a moderate size. However, these models might be useful to motivate future research exploring other solution approaches to solve this problem, such as decomposition methods, relaxation methods, heuristics, among others.  相似文献   

14.
Solutions to the two-dimensional, rectangular orthogonal packing problem rarely guarantee optimality, as exact algorithms require a prohibitive amount of computing time. A means of calculating the maximum number of boxes which can be fitted would be useful, both as a measure of optimality, and as an aspiration level. Existing estimates are accurate for approximately 15% of problems typically encountered in pallet loading applications. This paper discusses a technique for reducing the loading area before applying these estimates and shows that their effectiveness can be increased to provide an exact solution for over 70% of a random data sample.  相似文献   

15.
The manufacturer's pallet loading problem consists in arranging, orthogonally and without overlapping, the maximum number of boxes with dimensions (l,w) or (w,l) onto a rectangular pallet with dimensions (L,W). This problem has been successfully handled by block heuristics, which generate loading patterns composed by one or more blocks where the boxes have the same orientation. A common feature of such methods is that the solutions provided are limited to the so-called first order non-guillotine patterns. In this paper we propose an approach based on the incorporation of simple tabu search (without longer-term memory structures) in block heuristics. Starting from an initial loading pattern, the algorithm performs moves that increase the size of selected blocks in the current pattern; as a result, other blocks are decreased, eliminated or created. Computational results indicate that the approach is capable of generating superior order optimal patterns for difficult instances reported in the literature.  相似文献   

16.
分析了铁路运输中的平车装载问题,借鉴了First Fit算法的思想,并引入条件变异算子,提出了求解平车装载问题的一种改进遗传算法,给出了该改进遗传算法编码方法、遗传算子改进方案和适应度函数的定义,该算法能有效地解决初始群体和进化过程中的无效染色体和早熟问题,并用实例验证了该算法的有效性。  相似文献   

17.
Low back disorders in distribution centres or warehouses have been identified as an area of elevated risk in many industries. The task of an order selector requires workers manually to lift boxes from storage bins to a mobile pallet. This study explored the effect of box features and box location when lifting from a pallet in a storage bin upon spine loading. Ten experienced warehouse workers were asked to lift boxes from a pallet while the size, weight, handle features and location of the box on a pallet were changed. An EMG-assisted model was employed to assess spine compression, lateral shear and anterior-posterior shear during the lifts. The position from which the worker lifted a box on a pallet had the most profound effect on spine loading while the lower level of the pallet represented the greatest loadings on the spine. Box weight did not appear to be a feasible means of controlling spine loading unless its position on the pallet could also be controlled. The inclusion of handles had an effect similar to reducing the box weight by 4.5 kg, whereas box size did not effectively affect spine loading. The mechanisms by which these factors affect spine loading are discussed.  相似文献   

18.
一种平板车装载问题的启发式算法   总被引:6,自引:0,他引:6  
提出平板车装载问题的一各上启发式方法,不仅能够从几种型号的平板车中选择出一种装载性能较好的平板车,而且能够将具有不同特性的不同尺寸的物品放在该型号平板车中,它能够在满足一些约束条件下求得一种可行的装载方案,实例充分证明了该算法的有效性和实用性,能够直接用于实际生活中。  相似文献   

19.
任建伟  章雪岩 《控制与决策》2011,26(9):1353-1357
根据托盘共用系统调度的特点,建立了以托盘共用系统调度总成本最小为目标的两阶段随机机会约束规划模型.该模型综合考虑了需求随机、供给随机、运输能力随机、装卸能力随机等因素;采用机会约束规划方法对模型进行了确定性等价转换;通过算例进行了数值求解和数值分析,验证了模型的可行性和有效性.  相似文献   

20.
关于约束底盘装载问题的一种启发式方法   总被引:15,自引:1,他引:14  
已研究多年的底盘装载问题属于NP完备问题,关于它的解决方法多为启发式方法.本文讨论了约束底盘装载问题,并提出了一种基于计算机的启发式方法.实例表明,该方法能较好地解决约束底盘装载问题.  相似文献   

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