查询词典 on the threshold of

In this paper, a new real AdaBoost algorithm based on multithreshold method was developed. Through the selection method of multioptimization threshold and combining the strategy of weak classifier threshold selection in discrete AdaBoost algorithm, the rational division of sample space was implemented.

对基于连续AdaBoost算法的人脸检测方法进行了改进，结合离散AdaBoost中弱分类器的阈值选取策略，通过多重最优阈值选择方法实现了样本空间的合理划分。

Consider the dependencies between the coefficients and their parents, a non-Gaussian bivariate distribution is given, and corresponding nonlinear threshold function is derived from the model using Bayesian estimation theory. According to non-subsampled Contourlet transform and bivariate threshold function, a novel Non-Subsampled Contourlet Transform based on Bivariate threshold function for image denoising is proposed. This scheme achieves enhanced estimation results for images that are corrupted with additive Gaussian noise over a wide range of noise variance.

该文依据非下采样Contourlet分解系数与其父系数之间的相关性，给出非高斯双变量分布，对该模型应用Bayes估值理论推导得到相应的非线性双变量阈值函数，综合非下采样Contourlet分解和双变量阈值函数，提出一种基于双变量阈值的非下采样Contourlet变换图像去噪方法。

The main job and contribution of this paper are as follows:Based on narrowband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, compute the cross-correlation function of FH signals from multichannels, then we get the cross power spectral density matrixCSDM Secondly, select the hops of FH signals from the CSDM via processing and analyzing the CSDM, meanwhile reduce the influence coming from noise, fixed frequency signal and other interferences; Lastly, estimating the DOA of every hop and according to the DOA, we can separate the hops, get the number of FH signals and their parameters. Propose a new method for designing the threshold in FH signal detection. This method makes it easy to get the threshold by theoretic computing and it can extremely reduce the interference of non-FH signals.Based on broadband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, get the DOA of the signals by wideband spatial spectrum estimation; secondly, separate the signals by spatial filtering using wideband beamformer; Lastly, we propose two methods for FH signal blind detection and blind parameter estimation, one is for several constant hop-rate FH signals whose dwell-time are different and another is for a single FH signal whose hop-rate is alterable.By employing spatial interpolation in broadband signal beamforming, it can reduce the number of antenna elements and corresponding RF modules, A/D converters, etc. It can also eliminate the mutual coupling between antenna elements while getting the narrower main beamwidth and lower sidelobe level.

本文的主要研究工作和贡献如下：●提出了一种基于窄带处理的FH信号盲检测和参数盲估计的实现方法，即首先求出多路信号之间的互相关，进而得到互功率谱密度矩阵，然后通过对CSDM进行对折处理来抑制噪声、定频信号及其他干扰的影响，并将所有属于FH信号的hop(每一跳的驻留时间在时频图上持续的线段)从CSDM中筛选出来，最后用阵列信号处理中的到达方向估计理论在频域中估计出各个hop的方向参数，利用方位信息完成FH信号分离并得到FH信号的数目及其各自的参数集；●提出了一种确定FH信号检测门限的策略，该策略不仅使得检测门限能够通过理论计算得到，而且还显著地抑制了非跳频信号的干扰，从而能有效地检测出FH信号；●提出了一种基于宽带处理的短波FH信号盲检测和参数盲估计的实现方法，即首先利用宽带空间谱测向技术得到接收信号的DOA，然后采用宽带波束形成技术对特定方向进行空间滤波，实现多个信号的分离，最后分别提出了两种FH信号的盲检测和参数盲估计方法，第一种方法适用于空间某个特定方向上存在着几个驻留时间不同的恒跳速FH信号和其他干扰信号的混合信号，第二种方法适用于空间某个特定方向上仅含一个可变跳速的FH信号和噪声的混合信号；●将空间插值的概念和宽带波束形成技术结合起来，提出了一种基于频域处理的宽带恒定束宽的波束形成方法。

It is the first important step in video analysis and will directly affects the effectiveness of indexing Shot boundary detection is one of our major research interests and we will tackle the following existing problems the ambiguity between gradual change and camera motion, the discontinuity during gradual change, false detection caused by illumination variation and flashlight, automatic threshold selection Firstly, we discuss shot boundary detection in non-compressed domain In chapter 2, we compare some of the commonly used detection methods which are based on frame difference and point out that single feature will not generate good results As a conclusion, we use fuzzy logic to combine multiple features Presently, most frame difference based shot boundary detection algorithms rely on threshold and hence the selection of such thresholds will greatly affect the performance of boundary detection We propose a membership function to define frame difference and calculate the membership with self adaptation according to the statistic distribution of frame differences to satisfy different type of video clips Experiments show that the proposed fuzzy shot boundary detection algorithm can be used with different video types and has a high detection precision and recall In chapter 3, we discuss model-based shot boundary detection algorithms regarding chromatic and spatial editing effects such as fade-in, fade-out, dissolve and wipe Various parameters are proposed to better describe the characteristics of each editing type.

镜头边界的检测是把视频自动地分割为一个个镜头，作为基本的索引单元，因此它是视频分析重要的第一步，直接影响到视频检索的成败。镜头边界的检测是本文研究的重点之一。目前镜头边界检测算法主要存在以下问题：渐变与镜头运动难以区别；渐变过程中的不连续与停顿、光照条件的变化及闪光灯等特殊情况会引起误检测；自动选择阈值比较困难等。本文首先针对非压缩域视频进行了镜头边界检测的研究。在第二章中我们采用了比较流行的基于帧间差的方法。在比较各种帧间差计算方法的基础上，指出使用单一的特征难以取得很好的检测效果，提出用模糊逻辑综合使用各种特征。目前大多数基于帧间差的镜头边界检测算法都采用阈值法进行镜头转换的判别。阈值选择的误差对检测性能有较大的影响，本文提出用隶属度函数定义帧间差较大、中等较大和较小等概念，并根据帧间差的统计分布自适应地确定隶属度，以适应不同类型的视频片断。实验结果表明这种基于糊逻辑的镜头边界检测算法可以适应不同的视频，并具有较高的检测精度和检出率。在第三章中采用基于模型的方法进行镜头渐变的检测，研究了淡入／淡出、慢转换和扫换的模型。

Because energy distribution of interface trap is very important to study degradation of gate oxide we proposed two methods-- sub-threshold swing shift method and sub-threshold gate voltage shift method based on the relaxation spectral technique.

由于界面陷阱的能量分布在超薄栅氧化层退化研究中非常重要，因此基于弛豫谱技术我们提出了两种新的方法（亚阈摆幅漂移方法和亚阈栅电压漂移方法）来提取界面陷阱的密度及能量分布。

In order to conquer the threshold method's shortages,the threshold function is further improved through the simulation of channel's noise based on the translation invariant wavelet,which makes the threshold...

为了克服阈值法的不足，在平移不变量小波阈值去噪法的基础上，通过仿真低压电力线信道噪声，对阈值函数进一步改进，使阈值的变化与噪声的小波变换随尺度的变化特性相一致。

Based on having read a great deal of literatures about economic threshold, the authors pointed out the necessity and importance for applying the method of economic threshold in the studies of Phyllostachys pubescens ecosystem in this paper, and the authors also put forward the concept of economic threshold of Phyllostachys pubescens ecosystem and its research frame and some problems which should be pay attention to.

摘 要：在阅读大量有关经济阈值研究文献的基础上，创新地把经济阈值与毛竹林的科学研究结合起来，指出在毛竹林生态系统研究中，应用经济阈值研究手段与方法的必要性和重要性，并提出毛竹林生态系统经济阈值的概念、研究框架及其注意的一些问题，为毛竹林优化经营和丰产培育提供新的思路与技术。

We also study on the coding performance of these wavelet. At last, we investigate the wavelet threshold denosing for image, and present a improved Bayes denosing for image. We also combine the wavelet image coding with image denosing based on wavelet threshold, the noising image is compressed, the noise is de-noised at the same time.

最后，在对小波阈值的图像降噪原理进行分析的基础上，提出了一种改进的贝叶斯图像降噪方法，并将小波图像压缩和图像降噪结合在一起，来实现对噪声图像进行压缩的同时对它进行降噪。

The present study examines the application of these two theories on gender difference of age threshold and height threshold, by using individual level data on the mate selection web site in Taiwan.

本文用台湾地区择偶网站上的个人化资料，来分析年龄对择偶的年龄与身高门槛的影响，以此检验这两个理论的推论。

Based on Stuart et al.'s electron density evolution equation, the electron density evolution process in fused silica film irradiated by short-pulse laser for τ∈[0.015] ps were studied by means of numerical method. The effects of initial electron density N and laser pulse width τ on laser threshold intensity I and damage threshold fluence. F were analyzed respectively.

基于STUART等人的电子密度演化方程，运用数值模拟方法，研究了脉宽为τ∈[0.01， 5]ps范围内单脉冲激光作用下熔融石英薄膜中电子密度演化过程；讨论了初始电子密度、激光脉冲宽度对阈值功率密度和阈值能量的影响；分析了初始电子密度、激光脉冲宽度对多光子离化及雪崩离化的影响。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。