共查询到20条相似文献，搜索用时 468 毫秒
1.
为了定量求解生物病变组织的杨氏模量,提出了一种基于边缘提取技术和图像配准技术的杨氏模量反演方法.在已知生物组织边缘位移及病变边缘的基础上,根据力的分布,构造单元系统,运用有限元反演方法(IFEM),计算出组织的杨氏模量.在此基础上估计全局杨氏模量范围,采用改进粒子群优化算法(PSO),计算出生物组织整体的杨氏模量分布.该算法克服了其他杨氏模量重建算法的限制,放松了对位移和边界力的要求.通过多次数值实验得出算法对存在误差的边缘位移同样有效;改进的PSO算法在较大范围内叠代搜索,总能向理论值靠近,并得到可行解. 相似文献
2.
A new absorbing boundary condition(ABC) for frequency-dependent finite-difference time-domain algorithm for the arbitrary dispersive media is presented.The concepts of the digital systems are introduced to the (FD)^2TD method.On the basis of digital filter disigning and vector algebra,the absorbing boundary condition under arbitrary angle of incidence are derived.The transient electromagnetic problems in two-dimensions and three-dimensions are calculated and the validity of the ABC is verified. 相似文献
3.
基于半平面上的自然边界归化理论,给出一类带凹槽的半无界区域上椭圆型方程边值问题的非重叠型区域分解算法．证明算法具有与有限元剖分网格参数无关的收敛性,适当选取松弛因子,算法是几何收敛的,同时给出松弛因子的一般取值． 相似文献
4.
文章提出了一种平面散乱点集边界拟合算法,算法的基本思想是利用一种技巧对凸壳顶点进行筛选,使边界点迅速被找到,进而对其进行拟合。该算法能使用较少内存空间拟合平面散乱点集边界。设计了相应的vc程序验证了此算法。 相似文献
5.
本文提出了一种新的用于配电网络重构的优化方法－进化策略退火（ＥＳＡ）法,该方法将模拟进化策略法（ＥＳ）与模拟退火法（ＳＡ）进行了有机结合．首先用ＥＳ法选择ＳＡ法的初始温度,然后用改进ＳＡ法搜索重构的全局最优解．为加快寻优速度,本文提出了一种启发式规则用于降温策略,并采用了有效的潮流算法．仿真结果表明了ＥＳＡ法的有效性 相似文献
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7.
有Neumann边界条件的抛物型方程的初边值问题是偏微分方程研究领域的一类经典的问题。这是由已知的边界条件和初始条件来求区域温度场的问题。若所给边界是固定区域的称为定边界问题,而现实中又有一类问题其边界随时间变化,这样的问题称为动边界问题。文章对于时动边界上的热传导问题的求解提出人工边界的方法,并在人工边界的基础上采用了差分方法求解此定解问题。为了检验方法的可行性,给出了数值模拟。 相似文献
8.
分层制造中任意边界簿层分形扫描路径的研究 总被引：2，自引：0，他引：2
The fractal curve is proposed as a novel scanning-path used in Layered Manufacturing.Aiming at a limitation that the fractal curve can only fill a square region,a method is developed to realize the trimming of fractal curve in arbitrary boundary layer by means of undging intersection points between parameterized arbitrary boundary and a FASS(space-filling,self-avoiding,simple and self-similar)fractal curve.Accordingly,the related algorithm concerning with determining intersection points has been investigated according to the recursion reature of the fractal curve,and in the process of the fractal curve traversed,the rule of udging intersection points is ascertained as well,so that the laser-scanning beam can “walk” along the fractal curve inside the desired boundary,and arbitrary contour components are fabricated. 相似文献
9.
在视频镜头边界检测中,由于人眼视觉具备的主观性和视频帧图像结构与边界的不确定性,比较适合采用模糊理论,本文基于模糊集中的包含度理论提出双阈值化的视频镜头边界检测方法：首先基于包含度公式定义视频镜头边界检测函数,然后利用包含度理论提出视频边界镜头渐变和突变的通用检测算法,最后提出双阈值优化选取办法,实验结果表明本文方法具有较好的检测渐变和突变镜头能力。 相似文献
10.
ZHUJialin ZHANGTaiping 《重庆大学学报(英文版)》2002,1(1):47-52
A boundary element method based on non-overlapping domain decomposition method to solve the time-dependent diffusion equations is presented.The time-dependent fundamental solution is used in the formulation of boundary integrals and the time integratioin process always restarts from the initial time condition.The process of replacing the interface values,which needs a summation of boundary integrals related to the boundary values at previous time steps can be treated in parallel parallel iterative procedure,Numerical experiments demonstrate that the implementation of the present alogrithm is efficient. 相似文献
11.
快速多极边界元法是近几年发展起来的边界元新型数值算法,利用多极边界元法解题的关键和难点是求解大规模稀疏矩阵方程组,引入最优化数值技术很好地解决了这一问题,并通过数值实验验证,该方法可节约求解时间,从而为求解大规模问题奠定了理论基础。 相似文献
12.
基于均匀网格的自适应密度快速聚类算法 总被引：1，自引：1，他引：0
牟廉明 《内江师范学院学报》2008,23(8):32-36
提出了一种基于均匀网格的自适应密度快速聚类新算法．首先引入均匀网格和边界网格概念,然后给出了网格均匀度的计算方法和自适应网格划分技术．每次聚类都从均匀度最高的网格开始逐步向周围扩展均匀网格,直到遇到边界网格为止．算法除具有一般网格聚类算法的优点外,还能自适应地发现不同密度的类及其边界,能够有效地识别孤立点并具有较好的扩展性．最后,通过实验验证了该算法的有效性． 相似文献
13.
在求解Packing问题、机器人路径规划、虚拟装配、三维圆形管道作任意斜切割、医疗内外科手术等经常用到椭圆一矩形的干涉算法,本文基于Adamowicz ＆ Albano的NFP概念,提出了椭圆一矩形的静、动态不适合边界（No Fu Boundary,NFB）和计算方法． 相似文献
14.
针对视频中的运动目标离摄像头较近时由于形状的变化而导致目标边界测定不准确的问题,在帧间差分法的基础上,提出了一个求精运动目标边界的算法。先用得到边界值计算目标中心点,再对视频中的运动目标进行运动距离和速度的检测,并在Matlab中进行仿真。实验结果表明,该算法对帧差法的结果进行求精后,得到的运动目标的状态值更接近于实际情况,改进的算法更适合于视频中运动目标形状变化较大的情况下进行运动目标状态的检测。 相似文献
15.
Internal temperature is crucial to plant growth in the greenhouse. We investigated the patterns of constructing and managing greenhouses in Chongqing, and developed an algorithm of heating temperature for closed winter plastic greenhouses under the conditions of no man-made illumination, no ventilation and hot wind machine as the heating equipment which are the most adopted pattern of greenhouses in Chongqing area. The algorithm includes two functions of temperature outside the greenhouse, which calculate the values of the warming estimation coefficient （WEC） and the gap between temperatures inside and outside the greenhouse with the measured data of outside temperature, and then give the value of internal temperature; the heat rating of heating facilities required by a greenhouse can be determined by this algorithm with given values of floor area and internal temperature, measured outside temperature and calculated WEC. Verification of the algorithm demonstrates a desirable accuracy of estimation. Algorithms of computing heating temperature for greenhouses of different constructing and managing patterns and in different geographic conditions can also be derived in a similar way. This research presents a paradigm for developing a feasible method to fit out greenhouses with appropriate heating facilities, aiming at energy efficient and cost efficient production. 相似文献
16.
Internal temperature is crucial to plant growth in the greenhouse. We investigated the patterns of constructing and managing greenhouses in Chongqing, and developed an algorithm of heating temperature for closed winter plastic greenhouses under the conditions of no man-made illumination, no ventilation and hot wind machine as the heating equipment, which are the most adopted pattern of greenhouses in Chongqing area. The algorithm includes two functions of temperature outside the greenhouse, which calculate the values of the warming estimation coefficient (WEC) and the gap between temperatures inside and outside the greenhouse with the measured data of outside temperature, and then give the value of internal temperature; the heat rating of heating facilities required by a greenhouse can be determined by this algorithm with given values of floor area and internal temperature, measured outside temperature and calculated WEC. Verification of the algorithm demonstrates a desirable accuracy of estimation. Algorithms of computing heating temperature for greenhouses of different constructing and managing patterns and in different geographic conditions can also be derived in a similar way. This research presents a paradigm for developing a feasible method to fit out greenhouses with appropriate heating facilities, aiming at energy efficient and cost efficient production. 相似文献
17.
介绍了一种简单、快速的实时视频人脸对象跟踪算法．在使用肤色检测算法进行人脸区域定位的基础上,采用差分运动估计,确定最大的搜索区域,在此区域使用两个正交的边缘梯度跟踪模型和内部肤色像素统计直方图跟踪模型跟踪人脸．本算法较好地解决了跟踪的连续性、实时性和精确度间的矛盾．实验结果表明本算法能够对人脸进行实时跟踪,具有一定实际应用价值． 相似文献
18.
MALIK Pravin KADOLI Ravikiran GANESAN N. 《浙江大学学报(A卷英文版)》2007,8(7):1044-1052
Numerical exercises are presented on the thermally induced motion of internally heated beams under various heat transfer and structural boundary conditions. The dynamic displacement and dynamic thermal moment of the beam are analyzed taking into consideration that the temperature gradient is independent as well as dependent on the beam displacement. The effect of length to thickness ratio of the beam on the thermally induced vibration is also investigated. The type of boundary conditions has its influence on the magnitude of dynamic displacement and dynamic thermal moment. A sustained thermally induced motion is observed with progress of time when the temperature gradient being evaluated is dependent on the forced convection generated due to beam motion. A finite element method (FEM) is used to solve the structural equation of motion as well as the heat transfer equation. 相似文献
19.
张菊梅 《渭南师范学院学报》2012,(10):53-56
小波-DQ法是在微分求积（DQ）法的基础上建立起来的求解微分方程边值问题的新方法.文章以对流占优方程为例,对小波-DQ法的算法设计进行了探究. 相似文献
20.
勾朝阳 《渭南师范学院学报》2014,(23):12-16
等高线数字化过程中,等高线与边界是否无缝衔接关系到整个后续建模的成败。文章关于等高线与边界无缝衔接问题,在构建数字等高线数据结构的基础上,就数字等高线两端在边界内和在边界外分别编写了数字等高线首尾节点延长算法与裁剪算法,实现了数字化等高线与边界的计算机自动无缝衔接。最后通过实例验证了算法的可行性。 相似文献