基于SD的城市户籍改革中公共服务政策创新效应的动态仿真研究——以南昌市为例

在城乡户籍限制壁垒正逐步削弱的大背景下,实现城市常住人口公共服务均等化对于区域经济发展具有重要意义.应用系统动力学的逐树设撤关联数结构行为检验建模方法,建立仿真模型,通过设置户籍政策调控参数、公共教育支出参数、就业和社会保障支出参数及医疗卫生支出参数,分析不同情景下的政策实施效果,探讨城市户籍改革中公共服务创新政策效应...     

Investigation of point defects in silicon and germanium by non-irradiation techniques

We have derived a simple empirical formula for sputtering yields of monatomic metals and semiconductors, taking the threshold effect for knock-on of atoms into account in the Sigmund theory. It is found that this semi-empirical formula fits to the energy dependence of the sputtering yields over a wide range of ion-target combinations. The best fit values of the parameters for the formula are given as a function of the ratio of the mass of target atoms and the mass of incident ions.     

A quantitative comparison of two methods to correct eddy current-induced distortions in DT-MRI

Eddy current-induced geometric distortions of single-shot, diffusion-weighted, echo-planar (DW-EP) images are a major confounding factor to the accurate determination of water diffusion parameters in diffusion tensor MRI (DT-MRI). Previously, it has been suggested that these geometric distortions can be removed from brain DW-EP images using affine transformations determined from phantom calibration experiments using iterative cross-correlation (ICC). Since this approach was first described, a number of image-based registration methods have become available that can also correct eddy current-induced distortions in DW-EP images. However, as yet no study has investigated whether separate eddy current calibration or image-based registration provides the most accurate way of removing these artefacts from DT-MRI data. Here we compare how ICC phantom calibration and affine FLIRT (http://www.fmrib.ox.ac.uk), a popular image-based multi-modal registration method that can correct both eddy current-induced distortions and bulk subject motion, perform when registering DW-EP images acquired with different slice thicknesses (2.8 and 5 mm) and b-values (1000 and 3000 s/mm(2)). With the use of consistency testing, it was found that ICC was a more robust algorithm for correcting eddy current-induced distortions than affine FLIRT, especially at high b-value and small slice thickness. In addition, principal component analysis demonstrated that the combination of ICC phantom calibration (to remove eddy current-induced distortions) with rigid body FLIRT (to remove bulk subject motion) provided a more accurate registration of DT-MRI data than that achieved by affine FLIRT.     

物像空间位姿表征模型及标定技术研究

从对单目视觉系统的空间定位技术着眼，本文研究了一种利用标准平面镜反射辅助三维空间测量的模型和方法。首先基于摄像机标定的基本原理，以条纹反射检测系统为初始结构，建立应用标准镜测量显示屏的空间位姿的物理模型，然后在对摄像机标定不确定度进行实验标定的基础上，进行了对条纹反射检测系统的三维空间位姿描述和测量。研究结果验证了本文技术方法模型有效、精度较高，扩大了单目视觉系统的测量范围，获得了更加紧凑的物像空间位姿测量系统结构。     

Automatic alignment of infrared video frames for equipment leak detection

Petroleum refining and petrochemical industries start using infrared (IR) cameras to detect volatile organic compounds (VOC) leaking out of process equipment. However, further quantitative processing of these video image data or automatic recognition of VOC plumes are hindered by unaligned video frames owing to the slight vibrations of the camera. An automatic method is developed to align the IR video frames as a preprocessing procedure for other possible video processing methods. The alignment method is based on a two-dimensional spatial Fourier transform. The accuracy can reach fractional pixels in estimation of translational shift and 1-2° for rotational shift. Temporal Fourier transform of actual industrial tests of IR videos is performed with both unaligned and aligned video frames. The results indicate that only after the alignment of the video frames, the camera motion interferences on VOC plume identification can be eliminated or minimized, and the VOC plume can be identified through investigating the characteristic flickering frequency power in the temporal Fourier transform. This alignment method provides a useful tool for IR or other optical video image data preprocessing purposes.     

不同生长时期果树多源图像的配准方法研究

为了实现苹果树冠层的三维重建,指导智能剪枝、疏花和采摘,构建了集成光学混合探测(PMD)摄像机和彩色摄像头的图像采集系统,研究了不同生长时期的多源图像配准方法。从相似度评价指标和PMD图像的像素可靠性两个方面来描述果树不同生长时期图像的不同特征。结合图像的特征信息,提出了应采用基于深度信息的多源传感器标定技术,实现果树从开花期到成熟期的图像配准;对休眠期到发芽期的果树图像应采用基于图像特征的多源图像配准算法。对自然场景下的成熟期、休眠期、开花期果树图像共90组进行图像特征分析和不同配准方法试验验证,成熟期和开花期的匹配率达到100%,休眠期的匹配率达到86.11%。     

一种基于Canny边缘的红外与可见光图像配准算法

针对异源传感器在图像配准时如何精确地找到相应的匹配特征问题,结合红外图像与可见光图像的特征,利用2种传感器对同一场景成像时具有一定的边缘轮廓相似特性,提出了提取图像的Canny边缘,在边缘轮廓上根据边缘曲线上像素点的位置夹角的相似性寻找对应匹配点,通过仿真和实验数据与真实值的比较验证算法的有效性和配准的精度.     

网络环境下的医院门诊挂号预约系统改善研究

本文对改善挂号预约系统的模型进行了分析探索。根据病人的自报病情信息及医疗经验信息,通过量化的方法,对挂号预约阶段病人对疾病分类和症状程度划分进行了研究。研究结果有助于改善预约挂号系统。新的方法有助于解决挂号难的问题、有助于医疗服务质量的提高、并且有助于医疗资源的优化利用。     

复杂地物条件下基于线特征的异源景象匹配

为了寻求应用于复杂地物条件下异源景象匹配的算法,使其满足尺度和旋转不变性,受视觉成像系统的启发,利用初始简图可以表征图像大部分信息的特点,提出了一种新的基于线段对的异源图像匹配算法。首先,提取并筛选图像中能够表征图像信息的线段;然后,利用线段自身信息及线段的相对位置关系构建线段对特征;接着,通过线段对之间的相似性对图像进行粗匹配;最后,利用线段之间的拓扑关系进行精匹配。实验表明,本文方法对具有旋转、缩放和平移变换的异源图像的匹配正确率达到了75%以上,运算时间是传统匹配算法的1/5左右,基本满足了异源景象匹配应用对算法实时性和准确性的要求。     

三通道偏振成像系统及系统误差校正方法

为了解决现有偏振成像系统难以满足目标检测和跟踪等实时图像处理领域的要求,提出一种实时三通道偏振成像系统,并对该系统存在的视场差异和非一致性误差提出了校正方法.该系统采用三个独立通道采集0°、60°和120°方向上的偏振图像,针对三个独立通道之间存在的视场差异提出了采用尺度不变特征转换配准法进行校正的方法;同时针对三个独立通道之间的灰度响应非一致性现象,根据积分球的退偏特性和探测器的线性响应模型,利用积分球产生完全非偏振光对灰度响应非一致性误差进行了校正.对比实验证明:1)本文提出的三通道偏振成像系统进行校正后的成像效果能够接近单通道偏振成像系统的水平;2)该系统能够在实时采集图像的同时,克服了多通道带来的偏振图像质量下降问题,提高了实用性.