Interval parameter perturbation method for evaluating the bounds on natural frequencies of structures with interval parameters

For structural parameters with uncertainties, interval mathematics can, in the case where the probabilistic distribution density of uncertain variables is unavailable, deal with the influence of uncertainties in structural parameters on the response of structures. In order to evaluate the region containing natural frequencies of structures with interval parameters, the interval parameter perturbation method is presented in this paper. The advantage of the present method is its computational efficiency in evaluating the region containing natural frequencies. A numerical example is used to illustrate the efficiency of the method proposed. The project is supported by National Youth Natural Science Foundation of China and National Outstanding Youth Science Foundation of China.     

An Encryption Algorithm for Region of Interest in Medical DICOM Based on One-Dimensional eλ-cos-cot Map

Today, with the rapid development of the Internet, improving image security becomes more and more important. To improve image encryption efficiency, a novel region of interest (ROI) encryption algorithm based on a chaotic system was proposed. First, a new 1D eλ-cos-cot (1D-ECC) with better chaotic performance than the traditional chaotic system is proposed. Second, the chaotic system is used to generate a plaintext-relate keystream based on the label information of a medical image DICOM (Digital Imaging and Communications in Medicine) file, the medical image is segmented using an adaptive threshold, and the segmented region of interest is encrypted. The encryption process is divided into two stages: scrambling and diffusion. In the scrambling stage, helical scanning and index scrambling are combined to scramble. In the diffusion stage, two-dimensional bi-directional diffusion is adopted, that is, the image is bi-directionally diffused row by column to make image security better. The algorithm offers good encryption speed and security performance, according to simulation results and security analysis.     

基于形态学水线区域的深度图像分割

深度图像分割是基于特征关系图匹配的曲面物体识别中的关键技术之一,针对已有深度图像分割方法存在的问题,提出了一种基于二值形态学的水线区域增长算法对深度图像进行分割。首先用结构元素迭代腐蚀深度图像形成距离图像;然后根据距离图像计算极限腐蚀的集合,提取出目标的种子点;最后用条件粗化从种子点开始生长回到原尺寸但不使各区域相连,完成深度图像的分割。实验证明,算法的分割结果与人的主观视觉感知具有良好的一致性。     

Extremality and the global Markov property II: The global markov property for non-FKG maximal Gibbs measures

We give a condition on a Gibbs measure for an attractive Markov specification, which assures extremality and the global Markov property. As an example of application we consider the class of attractive Markov specifications defined on a compact configuration space over a two-dimensional lattice by the interaction Hamiltonians (assumed to have a finite set of periodic ground configurations) satisfying Peierl's condition. We prove that each extremal Gibbs measure for such a specification, at sufficiently low temperature, has the global Markov property.On leave of absence from the Institute of Theoretical Physics, University of Wrocaw, Poland.     

256色模式下图形图像处理系统中对不规则区域的处理

概述了图形图像处理系统中关于不规则区域的基本算法，包括：区域填充，边界跟踪，边界标志，几何处理，区域分割等等．并且，根据２５６色模式的特殊性，对传统的算法做了有针对性的改进，加快了处理速度，使其更适合于电影电视字幕、动画卡通人物等不规则图形图像区域．同时还给出了改进算法的程序设计的技巧．     

南疆铁路沿线区域人口发展和城镇化水平预测

根据南疆铁路沿线四地州人口发展过程和人口现状与城镇化水平现状,采用联合国人口基金提供的People人口预测软件和大型统计软件SPSS,以及联合国人品司推荐持用于预测世界各国城市人口的方法,简称URGD法,以1998年的统计数据为基础对区域的人口发展和城镇化水平进行了预测到2015年南疆铁路沿线地州人口将达到887万人,城镇化水平将达到37％,随后又对预测的意义进行了探讨,提出了人口发展规划和城镇化水平目标规划,并为规划的实现提出了几点主要的保障措施。     

空地激光通信系统中捕获子系统仿真

针对空地激光通信系统,推导了复合光栅螺旋扫描捕获方法所需的最大捕获时间、平均捕获时间和捕获概率的计算公式,建立了捕获性能仿真模型,分析了捕获时间和捕获概率的关系,以及空中平台的相对速度对捕获系统的影响和抑制方法.仿真结果表明,当通信终端的捕获不确定区域为50mrad,扫描重叠因子为0.12时,捕获探测器的信噪比大于6时,空地激光通信系统总的捕获概率优于95%,最大捕获时间约为36s,平均捕获时间约为12s.     

Collective bounce-off phenomenon in139La+Ag(Br) reaction at 1.1 A GeV energy

Out of a total statistics of 896¹³⁹La+Ag(Br) interactions, 128 interactions having multiplicity of target fragments (Z⩾1)⩾8 and projectile fragments (Z⩾2)⩾4 have been selected. They correspond to quasi-peripheral interactions. Azimuthal angle correlation between sources of target fragments (TFs) and projectile fragments (PFs) shows the existence of bounce-off effect. Using data of La+Ag(Br) and⁸⁴Kr+Ag(Br) reactions it is shown that individual helium [Z=2, PFs] and heavier fragment [Z⩾3, PFs] show different emission characteristics. Further, a two prong correlation functionT(Φ _ij ) plotted for heavier fragments and helium fragments separately, indicates the possibility of existence of different physical conditions. This observation is supported by the different momentum widths of helium fragments and heavier fragments. From the momentum width data of Kr+Ag(Br) reactions normalized density comes out to be ≈4.7. Using quasi-elastic kinematics for the bounce-off nuclei, the excitation energy has been computed from the experimental data of flow angles. The strength of bounce-off seems to decrease with the increase of excitation energy or temperature.     

非晶态HoP5O14的蓝绿波段上转换发光的分析

本文报道了脉冲ＤＣＭ染料激光导致的非晶态ＨｏＰ５Ｏ１４的兰绿波段的上转换发光现象，从实验和理论上对其上转换发光的现象，机理和能道行了测量，分析和计算；结果表明对＾５Ｆ３和Ｓ２能级，其上转换发光主要由离间能量传递机理导致；对５Ｇ４和（５Ｇ３Ｇ）５能级，则步进双光子吸收和离子间能量传递共同参与导致了它们的上转换发光。     

JMCT优化查找策略的实现

分析连续能量点截面中子输运程序JMCT中区间查找的时间复杂度.针对主能量网格,裂变释放中子数和不可分辨共振网格进行区间映射加速,并以等差和等比序列网格为例,对比分析不同散列网格的质量.最后选择寿期初与寿期中燃料棒栅元的k_∞问题进行对比测试.结果显示,对于核素数目较多的输运问题,优化查找策略具有很好的加速效果.