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Among used machine learning methods, the gradient descent method is widely used to train various classifiers, such as Back-propagation neural network and linear text classifier. However, the gradient descent method is easily trapped into a local minimum and slowly converges. Thus, this study presents a gradient forecasting search method based on prediction methods to enhance the performance of the gradient descent method in order to develop a more efficient and precise machine learning method for Web mining.However, a prediction method with few sample data items and precise forecasting ability is a key issue to the gradient forecasting search method. Applying statistic-based prediction methods to implement GFSM is unsuitable because they require a large number of data items to model a prediction model. In the contrast with statistic-based prediction methods, GM(1,1) grey prediction model does not need a large number of data items to build a prediction model, and it has low computational load. However, the original GM(1,1) grey prediction model uses a mathematical hypothesis and approximation to transform a continuous differential equation into a discrete difference equation in order to model a forecasting model.

其中梯度法是一个最常被使用来实现机器学习的方法之一,然而梯度法具有学习速度慢以及容易陷入局部最佳解的缺点,因此,本研究提出一个梯度预测搜寻法则(gradient forecasting search method, GFSM)来改善传统梯度法的缺点,用来提升一些以梯度学习法则为基础的分类器在资讯探勘上的效率与正确性;而一个所需资料量少、计算复杂度低且精确的预测模型是梯度预测搜寻法能否有效进行最佳解搜寻之关键因素,传统统计为基础之预测方法的缺点是需要较大量的数据进行预测,因此计算复杂度高,灰色预测模型具有建模资料少且计算复杂度低等优点,然而灰色预测理论以连续之微分方程式为基础,并且透过一些数学上的假设与近似,将连续之微分方程式转换成离散之差分方程式来对离散型资料进行建模及预测,这样的作法不尽合理,且缺乏数学理论上的完备性,因为在转换过程中已经造成建模上的误差,且建模过程仅考虑相邻的两个资料点关系,无法正确反应数列未来的变化趋势。

The surface representation in discrete form and its differential computation are important issues in computer graphics and geometric design.

0引言一般来说,曲面的一阶微分量是指曲面的切平面方向和法向量,二阶微分量是指曲面的曲率等有关量·它们作为重要的曲面信息度量指标,在计算机图形学,机器人视觉和计算机辅助设计等领域发挥了重要的作用·传统的曲面是连续形式的参数曲面和隐式曲面,其微分量的计算已经有了较完备的方法·随着激光测距扫描等三维数据采样技术和硬件设备的长足进步,以及图形工业对任意拓扑结构光滑曲面造型的需求日益迫切,离散形式的曲面———细分曲面、网格曲面和点云曲面正在逐渐成为计算机图形学和几何设计领域的新宠·于是,对这种离散形式的曲面如何估

Recent years as development of the computer and software, it becomes reality using numeric simulation to research grouting in clay. Using the software of PFC2D, the grouting in clay is lucubrated and such achievements are reached: Grouting technologies in existence grouting material and serosity are studied and rational methods are put forward in choosing grouting technology and serosity.(2) Base on numeric simulation biax test a method is explored to simulate clay with PFC2D.(3) A method is explored to simulate grouting using PFC2D.(4) The relation between serosity pressure and diffuseness of grouting in clay with different initial stress is studied.(5) The stress transformation of clay is studied during grouting.(6) The stress distribution is studied under different serosity pressure.(7) The normal stresss and shear stresss at any section are studied.

近年来随着计算技术的发展,使得采用数值模拟的方式研究均质土体中的注浆成为可能,本文则利用离散元程序PFC2D对均质土体中注浆进行了研究,主要做了以下几方面的工作:(1)研究了现有注浆加固技术、注浆材料以及浆液的性质,阐述了合理选择注浆方式以及浆液的方法;(2)采用数值双轴实验,探索了应用离散元模型模拟土体的方法:(3)探索了采用颗粒流程序进行注浆数值模拟的方法途径;(4)研究了在粘土中注浆不同侧向土压力条件下浆液扩散范围与注浆压力规律;(5)研究了注浆过程中不同阶段土体中压应力的变化;(6)研究了不同注浆压力对土体应力分稚的影响:(7)研究了注浆过程中土体中任一截面处正应力与剪应力的对比关系。

By using the transfer matrix method of multibody system, the hard problem of computation of the vibration characteristics of LRMLRS coupled with rigid bodies and elastic bodies is solved which is very difficult to the ordinary dynamic methods, and the vibration characteristics of LRMLRS which is varied when the number of rockets in the launch device is varied, is obtained conveniently. By developing augmented eigenvectors of the LRMLRS and its orthogonality conditions, the nonorthogonality problem of the multibody system including rigid bodies and elastic bodies is solved and the exact analysis of the dynamics response of the LRMLRS including rigid bodies and elastic bodies is realized. By using the random integer programming method, the hard optimization problem which contains continuous variables, discrete variables and random variables at the same time is solved. This method provides a technology for optimum design with random variables and discrete variables. The dynamic optimum design is realized to decrease the number of rockets consumption in the LRMLRS test. The simulation system of dispersion of fire is established by using the maximum entropy method to estimate dispersion of fire.

通过应用多体系统传递矩阵法,解决了刚弹耦合远程多管火箭多体系统振动特性这一通常力学方法不便于解决的计算难题,方便地获得了远程多管火箭振动特性及其随发射架上火箭弹个数变化而变化的情况;通过构造增广特征矢量及其正交性条件,解决了刚弹耦合多体系统特征矢量不具有通常意义下的正交性的难题,实现了对刚弹耦合远程多管火箭动力响应的精确分析;应用随机整数规划法,解决了同时考虑连续、离散和随机变量等多种设计变量的优化设计难题,为含随机和离散变量的优化设计提供了手段,实现了减少远程多管火箭试验用弹量的动态优化设计;建立了应用最大熵法估计的密集度仿真系统,优化射序和射击间隔,实现了提高远程多管火箭射击密集度的动态优化。

In this paper, by discussing the basic hypotheses about the continuous orbit and discrete orbit in two research directions of the background medium theory for celestial body motion, the concrete equation forms and their summary of the theoretic frame of celestial body motion are introduced. Future more, by discussing the general form of Binet's equation of celestial body motion orbit and it's solution of the advance of the perihelion of planets, the relations and differences between the continuous orbit theory and Newton's gravitation theory and Einstein's general relativity are given. And by discussing the fractional-dimension expanded equation for the celestial body motion orbits, the concrete equations and the prophesy data of discrete orbit or stable orbits of celestial bodies which included the planets in the Solar system, satellites in the Uranian system, satellites in the Earth system and satellites obtaining the Moon obtaining from discrete orbit theory are given too.

摘 要:通过讨论天体运行背景介质理论的连续轨道及离散轨道这二个研究方向的基础假设,介绍了天体运行轨道的具体方程形式及理论框架概要;进一步地通过讨论天体运行轨道 Binet 方程的一般形式及其行星近日点进动角的解,给出了连续轨道理论与 Newton 理论及 Einstein 广义相对论的联系与区别;通过讨论天体运行轨道的分维扩展方程,给出了包括太阳系行星、天王星卫星、地球卫星、绕月航天器等在内的离散轨道方程及其预言数据。

Many new detection techniques are proposed, that include: To overcome the faults of cross-terms and short unambiguity range for the common Wigner-Ville Distribution , short-time Fourier transform and Gabor transform are applied to SAR moving target detection. To improve the detection performance of WVD in noise environment, a new technique based on the Cross-WVD is proposed. The application of fractional Fourier transform to chirp signal detection is analyzed and extended to SAR moving target detection. To eliminate the restriction of chirp-Fourier transform, a new modified definition is proposed and applied to SAR moving target detection. To detect multiple moving targets whose scattering intensities are different heavily, the CLEAN technique is combined with the above techniques and the ideal detection performance is achieved. At last, the whole dissertation is concluded.

具体的研究成果如下:针对常用的Wigner-Ville分布在多目标情况下存在交叉项,并且多普勒不模糊范围小的缺点,提出将短时Fourier变换和Gabor变换应用于SAR运动目标检测,分析了其优势所在;为进一步提高Wigner-Ville分布低信噪比条件下的信号检测能力,提出基于互Wigner-Ville分布的运动目标检测方法;分析了分数阶Fourier变换在线性调频信号检测中的应用,提出基于分数阶Fourier变换的运动目标检测算法;对离散Chirp-Fourier变换的定义进行了修正,提出修正的离散Chirp-Fourier变换,克服了限制其应用的约束条件,并用于SAR运动目标检测当中;强度相差较大的多运动目标检测历来是机载SAR技术的一个重点和难点,我们将CLEAN思想融入上述多种算法当中,良好地解决了该问题。

At first, setting up the arith relation between the signal input and the signal output of the generalized multi-carrier system of the Discrete Fourier Test spread-spectrum; then setting equilibria parameters of the frequency field equilibria subcarrier of the generalized multi-carrier system of the DFT spread-spectrum according to channel frequency response, channel noise variance and equilibria method; then calculating average power of useful signal, interferential average power between signals as well as noise variance of the generalized multi-carrier system receiving terminal of the DFT spread-spectrum according to the arith relation as well as the frequency field equilibria parameter, and recomputing available signal information noise ratio, so as to calculate the available signal information noise ratio of the generalized multi-carrier transmission system accurately, the method for estimating the available signal information noise ratio can be used for link self-adapting transmission solution of the generalized multi-carrier system based on Discrete Fourier Test spread-spectrum and radio material management.

一种DFT扩频的广义多载波系统的SINR估计方法,其通过首先建立所述离散傅立叶变换扩频的广义多载波传输系统的信号输入输出之间的数学关系,然后根据信道频率响应、信道噪声方差和均衡方法,设定所述DFT扩频的广义多载波传输系统的频域均衡子载波的均衡系数,再根据所述数学关系及所述频域均衡系数分别计算所述DFT扩频的广义多载波传输系统接收端有用信号的平均功率、信号间干扰的平均功率以及噪声方差,再计算有效信干噪比,如此以实现对广义多载波传输系统的有效信干噪比的准确计算,该有效信干噪比估计方法可用于基于离散傅立叶变换扩频的广义多载波传输系统的链路自适应传输方案和无线资源管理方面。

Traditionally, a surface is usually scatted in an array of 3D data points which are topologically connected by rows and columns to form a rectangular mesh. This method can't meet the requirement of description and measurement for some complex surfaces. On the basis of tracing border points, a new method is proposed to deliver 3D data points of surfaces, which are topologically constructed with optimum rectangular and triangular mesh. In order to measure surface efficiently and safely with NC machine, an optimization of measurement paths is proposed to avoid interference between the measuring tool and the surface with holes. The curve design is the basis of surface modeling.

数控测量技术的发展为测量自动化、集成化、智能化提供了可能,而对于复杂曲面的自动测量规划则是测量技术中的难点问题,平行截面等数目测点分布和四边拓扑测点分布规划方法,不论在测点分布的合理性上还是在网格结构的优化方面,均难以满足形状或边界较复杂曲面的离散化描述和曲面造型的要求,为了实现任意拓扑曲面的自动测量,本文对复杂曲面的合理离散化描述和自动测量问题进行了研究,提出了基于边界跟踪、优化网格的测点自动分布规划和四边、三角混合网格的生成方法:同时对具有孔洞或测量干涉凸台等非完整曲面的测量路径优化问题进行了研究,提出了路径优化方法。

Secondly, two physical models were constructed, which could model rough surface and describe the features of the earth surface, such as chine, neck, valley and hill, etc. According to difference method, the ""true"" volume of the physical models were measured, which was 13260cm3 and regarded as the analysis foundation of the precision of the volume that was calculate by DEM. The discrete dada of the models on a regular spacing of 1cm were collected by 3SPACE FASTRAK and the DEM was obtained by interpolating the discrete dada through GIS software. Based on the volume of the models calculated by DEM, different interpolating methods (IDW, Spline, Natural Neighbor, and Kriging) and variation of grid spacing of data were compared and their effects on precision of volume calculation were analyzed.

构建了可模仿凸凹不平地形表面的实体模型,该模型能够表征山脊、山尖、山涧、丘陵等地形特征;根据体积差减法测量实体模型的体积作为数据精度分析的体积&真值&,该值为13260cm~3,作为采用DEM进行体积计算的基准值;利用精度为0.08cm的三维数字化仪采集间距为1cm的离散数据点,对离散数据点用GIS软件进行内插处理生成DEM模型,通过DEM计算出模型的体积,探讨不同内插方法(IDW、Spline、Natural Neighbor和Kriging)和数据格网间距变化对体积计算精度的影响。

Based on analyzing the algorithms of Delaunay triangulation creation in domestic and abroad, in view of the situation of building DTM and the need of realizing railway 3D visual design, a divide-and-conquer algorithm to build DTM is presented, the algorithm use square grids to manage disordered points, to form triangular meshes in grids, DTM can be obtained by merging the triangular meshes, so that the work of sorting of the disordered points before building DTM is reduced greatly; moreover, the algorithm utilize subarea to control the vertices of convex hull so that the range which support points locate in can be predefined when searching support points, the workload of searching support points can be reduced and the speed of merging two triangulations is raised.

在分析了国内外构建DTM算法的基础上,针对DTM算法的现状及铁路线路三维可视化设计的需要,创立了一种构建DTM的分治算法。算法引入方格网管理离散点数据,在格中构建三角网,然后再将这些三角网合并形成DTM,极大地减少了构网前对所有参加构网的离散点进行排序的工作量。此外,通过对凸包顶点数据进行分区管理,在搜寻凸包支撑线时,能预先确定出支撑点的范围,减少了搜索工作量,提高了三角网的合并速度。

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推荐网络例句

Singer Leona Lewis and former Led Zeppelin guitarist Jimmy Page emerged as the bus transformed into a grass-covered carnival float, and the pair combined for a rendition of "Whole Lotta Love".

歌手leona刘易斯和前率领的飞艇的吉他手吉米页出现巴士转化为基层所涵盖的嘉年华花车,和一双合并为一移交&整个lotta爱&。

This is Kate, and that's Erin.

这是凯特,那个是爱朗。

Articulate the aims, objectives and key aspects of a strategic business plan.

明确的宗旨,目标和重点战略业务计划。