Genetic Algorithms to the Nesting Problem in the Leather Manufacturing Industry

The nesting problem in the leather manufacturing is the problem of placing a set of irregularly shaped pieces (called stencils) on a set of irregularly shaped surfaces (called leathers sheets). This paper presents a novel and promising processing approach. After the profile of leather sheets and stencils is obtained with digitizer, the discretization makes the processing independent of the specific geometrical information. The constraints of profile are regarded thoroughly. A heuristic bottom-left placement strategy is employed to sequentially locate stencils on sheets. The optimal placement sequence and rotation are deterimined by genetic algorithms (GA). A natural concise encoding method is developed to satisfy all the possible requirements of the leather nesting problem. The experimental results show that the proposed algorithm can not only be applied to the normal two-dimensional nesting problem, but also especially suitable for the placement of multiple twodimensional irregular stencils on multiple two-dimensional irregular sheets.     

基于组合导航与EKPF飞行器的地形边界与面积估计

提出了一种使用四旋翼飞行器作为测量平台的地形边界与面积估计算法.该算法采用紧耦合闭环组合导航系统(捷联惯性导航系统与全球卫星定位系统)获取待测地形边界点的定位数据,分别使用Pauta准则与扩展卡尔曼粒子滤波方法剔除异常数据与处理定位数据.算法在得到的最终定位数据的基础上,估算待测地形与面积.飞行器使用前视和下视摄像头确定飞行方向和选择边界点.使用该算法可以实现不规则的凸多边形、凹多边形和弧段等地形的精确估计,估计误差可以在±1.2%以内.实际飞行实验结果验证了该算法的可行性和准确性.     

An Image Encryption Method Based on Bit Plane Hiding Technology

A novel image hiding method based on the correlation analysis of bit plane is described in this paper. Firstly, based on the correlation analysis, different bit plane of a secret image is hided in different bit plane of several different open images. And then a new hiding image is acquired by a nesting ＂Exclusive-OR＂ operation on those images obtained from the first step. At last, by employing image fusion technique, the final hiding result is achieved. The experimental result shows that the method proposed in this paper is effec rive.     

导弹拦截的混杂对策系统建模研究

导弹拦截系统中既存在轨迹的连续变化过程,也存在策略的选择问题,单独采用微分对策和事件对策均无法有效描述该系统的混杂特性.将该过程看作一类混杂系统,提出一种导弹拦截过程(missile interception process, MIP)的混杂对策建模方法.基于混杂随机时延Petri网(hybrid stochastic timed Petri net, HSTPN)建立导弹拦截事件对策模型,结合导弹飞行过程的动力学模型建立拦截过程的微分对策模型;以“民兵Ⅲ”导弹作为进攻弹,对MIP的混杂过程进行实例仿真.结果证明,采用混杂对策建立的导弹拦截混杂描述方案,既可以较好地描述导弹轨迹的连续变化过程,也可以描述策略的选择问题.     

面向地理信息系统的三维空间数据模型

通过分析三维ＧＩＳ空间数据模型的基本概念、研究进展及所存在的问题,在三维空间实体的形式化定义及空间实体间拓扑关系形式化描述等研究基础上,建立了顾及空间剖分的三维拓扑数据模型。该模型不但可以有效地表达规则形状的空间实体,还可以有效地表达不规则形状的空间实体。它兼顾了基于镶嵌的数据模型和基于矢量的数据模型两种表示方法的优点,为发展三维ＧＩＳ软件提供了一些有益的设想和方法,可以使得系统在数据组织、数据管理、图形恢复上避免不必要的麻烦,并可望使空间查询和空间分析具有高效性     

Monitoring the Cultivated Slope Land in the Three Gorges Reservoir Area Based on Remote Sensing and GIS

0IntroductionCultivatedlandis the basis for human survivaland development.Its composition,change,and sustainable use are undoubtedly i mportant fac-tors havingi mpact onthe sustainable development ofan area.There are high mountains andsteepslopes,alarge population andlittle cultivatedlandin ThreeGorges Reservoir Area.The Geographic distributionof cultivated land is extremely unreasonable,andcultivatable land resources are li mited.With poorwater resource facilities,weak disaster resistancea…     

Wigner frequency point slice analysis of superposition data for phased-array ground penetrating radar

According to the frequency property of Phasedarray ground penetrating radar (PGPR), this paper gives a frequency point slice method based on Wigner time-frequency analysis. This method solves the problem of analysis for the PGPR‘s superposition data and makes detecting outcome simpler and detecting target more recognizable. At last, the analytical, results of road test data of the Three Gorges prove the analytical method efficient.     

基于最小势能原理的不规则零件排样算法

提出了一种基于最小势能原理的不规则零件排样算法(HAPE),揭示了排样问题的物理意义:零件总是试图通过平移和旋转运动尽量降低零件的重心高度,从而得到更加紧密的排列.为了寻找最优排样姿态使零件重心最低,需要在母材上均匀布置一些点,让零件在每个点间隔一定的角度进行旋转.算例表明,HAPE是可靠的,且物理意义明确,不需要计算...     

任意多边形无叠接靠拢算法的研究与实现

CAD 中常遇到这样一个问题:已知一多边形的位置,如何按指定方向放置另一多边形,使这二多边形以最紧密的方式排放,但不发生叠接现象?以往的方法繁琐,计算时间长。本文介绍一种新型的快速靠拢算法。该算法基于投影法上,再适当使用旋转处理和隐藏区域处理,使判断仅基于有限的多边形顶点,简化了处理过程。本算法可适用于任意多边形,可广泛用于计算机辅助机械落料,集成电路 CAD 中的布局,飞机、汽车制造业中的裁剪,制鞋、制帽和服装中的排料等领域,也为自动排料提供了优化算式的基础。     

Research on Fault Tolerant Scheduling Algorithms of Web Cluster Based on Probability

Aiming at the soft real time fault tolerant demand of critical web applications at present, such as E-commerce, a new fault tolerant scheduling algorithm based on probability is proposed. ““““““““Ib achieve fault tolerant scheduling, the primary/slave backup technology is applied on the basis of task‘s self similar accessing characteristics, when the primary task completed successfully, the resources allocated for the slave task are reclaimed, thus advancing system‘s efficiency. Experimental results demonstrate on the premise of satisfying system‘s certain fault tolerant probability, task‘s schedulabilistic probability is improved, especially, the higher task‘s self similar degree is, the more obviously the utilization of system resources is enhanced.     

混合动力汽车控制策略硬件在环仿真开发平台

为提高混合动力系统仿真的精度,有效开发控制策略,提出了一种硬件在环的混合动力系统实时仿真开发平台.建立了混合动力系统的动态模型,搭建了包含实车控制器的驾驶员硬件在环实时仿真平台.针对一款ISG混合动力汽车进行了仿真实验.结果表明,建立的实时仿真系统能比较准确地模拟实车特性,取得了良好的效果.     

一类三维耦合混沌系统的动力学分析与数值模拟

通过对一个三维不稳定线性系统添加非连续状态反馈控制项,即一个分段线性控制开关,从而构造出一种新的几何对象,实现了三线性系统耦合混沌控制. 对一类三维耦合混沌系统的动力学性质进行了理论分析,给出了与此类系统动力学性质相关的三个定理. 数值模拟及计算全部Lyapunov指数验证了该三维耦合系统确实存在混沌.     

A Geometrical Transformations Resistant Digital Watermarking Based on Quantization

A geometrical transformations resistant digital image watermarking based on quantization is described. Taking advantage of the rotation, scale and translation invariants of discrete Fourier transform(DFT), each watermark bit is embedded into each homocentric circles around the zero frequency term in DFT domain by quantizing the magnitude vector of Fourier spectrum. The embedded sequence can he extracted by ““““““““majority principles““““““““ without restoring to the original unmarked image. The experimental results show that the watermark is invisible and robust to any combination of geometrical transformations or common image processing techniques.     

Simulation of the RCS Range Resolution of Extremely Large Target

,,,.lr.0　IntroductionThe RCS(Radar Cross Section) of a target in the near zone is very important in the various civilian and militaryfields. For a complex target, we dissect it in the near zone tomany small regions and simulate the RCS of the the whole …     

基于细化和最小生成树的多边形主骨架线提取

现有的不规则多边形主骨架线提取方法存在设计复杂、执行效率低等缺点,对此提出一种基于细化和最小生成树的多边形主骨架线提取方法 .首先,确定多边形的最小包围盒,并在其中生成均匀分布、数值分别为0或1的点,运用细化算法提取多边形骨架;再利用Prim算法生成最小生成树;最后,计算最小生成树上的两个叶子节点间的路径长度,将长度最长的路径定义为主骨架线.实验结果表明：本方法提取出的主骨架线效果较好,具有一定的实用性.     

机器人路径规划的凸点法

在具有障碍物的凸多边形或凹多边形的二维环境中，用不断搜索凸点的方法规划任意两点间的无碰路径，与其他方法相比，其规划速度快，优化后的路径质量较好．     

A Novel Digital Audio Watermarking Scheme in the Wavelet Domain

We present a novel quantization-based digital audio watermarking scheme in wavelet domain. By quantizing a host audio‘s wavelet coefficients (Integer Lifting Wavelet Transform ) and utilizing the characteristics of human auditory system ( HAS), the gray image is embedded using our watermarking method. Experimental results show that the proposed watermarking scheme is inaudible and robust against various signal processing such as noising adding, lossy compression, low pass filtering, re-sampling, and re-quantifying.     

Photocatalytic Oxidation of NOx with Porous TiO2 Nanometer Thin Film

A new kind of porous nano-TiO2 composite films was prepared on the glass substrate with the water glass as hinders and the sodium fluorosilicate as solidifying reagent. The morphologies of the films were studied by scanning electron microscope(SEM). The UV-Vis spectrophotometer was also used to investigate the absorption of the films. The gasphase photocatalytic oxidation of nitrogen oxides on the composite film was carried out in TiO2 UV system, and some important factors affecting the photocatalytic oxidation were also studied such as the catalyst concentration, vapor pressure and the presence of oxygen. The results showed the conversion of NOx reached 97.5% after 2 h UV-irradiation. The final product of photo-oxidation was detected to be HNO3 hy FT-IR. The way of photocatalytic oxidation of NOx was possibly useful in the practical application.     

Automatic Question Answering from Web Documents

A passage retrieval strategy for web-based question answering （QA） systems is proposed in our QA system. It firstly analyzes the question based on semantic patterns to obtain its syntactic and semantic information and then form initial queries. The queries are used to retrieve documents from the World Wide Web （WWW） using the Google search engine. The queries are then rewritten to form queries for passage retrieval in order to improve the precision. The relations between keywords in the question are employed in our query rewrite method. The experimental result on the question set of the TREC-2003 passage task shows that our system performs well for factoid questions.     

A two-layer real-time rate control algorithm based on lagrange optimum algorithm

Because of the iterative process in the rate control algorithm of H.264 draft, it is not suitable for real-time transmission. A two-layer real-time rate control algorithm based on Lagrange optimum algorithm is proposed. This algorithm consists of two layers, namely, the group of pictures (GOP) layer and the frame layer. The simulation results show that the proposed algorithm is competitive in terms of peak signal to noise ratio (PSNR), real bitrates and the Q-value among frames over the original algorithm. Foundation item: Supported by the National High-Technology Research and Development Program of China (863 Program) (2001AA132050-03) and the Key Project of Chinese Ministry of Education (211CERS-10)