查询词典 on the threshold

Comparing the mean of hearing threshold in each group at different frequency band, the threshold of audibility on 0.5, 1, 2, 3, 4, 6kHz was 22.98±6.28dB, 21.38±7.88dB, 22.04±10.19dB, 26.55±16.69dB, 31.52±18.86dBand 33.75±19.71dB, respectively.

联合组听力异常率明显高于单纯噪声组和对照组(P.05)，高频、语频、Ⅱ级、Ⅲ级及Ⅲ级以上听力损伤率均较噪声组、对照组明显升高(P.05)。

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。

From this model, we can find how the channel length, channel doping concentration, the thickness of silicon film and gate oxide influences the threshold voltage, and the variation of threshold voltage is independent on back-gate bias.

从模型中可以容易地分析阈值电压与沟道浓度、长度、SOI硅膜层厚度以及栅氧化层厚度的关系，并且发现△V与背栅压的大小无关。

Secondly, this thesis simulates CDMA Soft Handoff by using Hata transmition model and the threshold parameters on Visual C++ platform. Then through relevant experiments, it validate the impact of CDMA system threshold parameters in switching.

通过对软切换的分析，利用Hata传播模型和切换规则设置相关门限参数并在Visual C++平台上实现软切换的仿真设计，并通过相关实验，验证了CDMA系统中软切换各项参数取值对CDMA切换产生的影响，能够仿真CDMA切换功能。

Based on the principle of Otsu method with maximum variance between threshold algorithm of image segmentation, an improved method derived from Otsu algorithm is put forward, which combines interclass distance with intraclass distance, a partial recursive algorithm is used to search optimum threshold.

基于最大类间方差阈值图像分割算法的基本原理，然后结合目标与背景两类之间间距和类内距离对图像分割效果的影响，提出了一种改进的最大类间方差法，运用递归思想局部搜索图像的最佳阈值。

Based on the elliptic curve cryptography and Shamir threshold mechanism, an anti-deception threshold signature scheme is proposed.

基于椭圆曲线密码体制，利用shamir的门限机制，提出了一种可以防欺诈的门限签名方案。

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。

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。

Paired t-test analysis was performed on the thresholds of SVR and PTA at each frequency (0.5, 1, 2 and 4kHz), and analysis of variance was performed on the difference between the pure tone audiometry threshold and the evoked potential threshold among different frequency.

对听力正常的46名志愿者，分别对双耳进行0.125~8kHz频率范围内的PTA阈值及0.5~4kHz频率范围内的SVR反应阈测试，通过配对t检验比较0.5、1，2、4kHz频率范围的SVR反应阈与PTA阈值的差异，并运用方差分析比较不同频率间的SVR反应阈与PTA阈值差值的差异。

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。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。