查询词典 spectral density

Dynamic reliability under Littlewood-Paley wavelet is the biggest, dynamic reliability under modified meyerwavelet and harmonic wavelet are close. Analyzing the dynamic reliability of structure under odd exponent wavelet is very simple, it doesnt calculate Power Spectral Density function integral, it is only to calculate the square of displacement standard deviation and the square of velocity, then the dynamic reliability of structure can be concluded by max distribution. In addition the effects of upper limit is considered, when upper limit is smaller, the dynamic reliability of structure is less, that is, the damage possibility is bigger.

通过结构地震反应在小波基下的动力可靠性分析说明：无论是单自由度还是多自由度从理论上推导在这四种小波下的结构动力可靠性是可行的，而且考虑的结构地震反应都是非平稳的高斯过程，方法实现也比较容易；在Littlewood—Paley小波基下求得的结构的动力可靠度比较大，由改造的meyer小波和谐波小波求得的动力可靠度略有差异；单边指数小波下的结构动力可靠性分析非常简单，不用求功率谱函数来积分，只需求得结构地震反应的位移方差，速度方差，利用最大值分布公式就可得到结构的动力可靠时程；另外也考虑了超越界限对结构动力可靠度的影响，超越界限越小，结构的动力可靠度越小，即破坏概率越大。

In terms of the ground disturbance power spectral density, the H2 norm is used to describe the requirement for ride comfort and the generalized H2 norm is adapted to capture time-domain constraints such as good road holding.

根据路面干扰谱特征，选用H2范数作为乘坐舒适性的指标，广义H2范数描述轮胎接地性等时域约束要求。

The degree of PIM interference can be understood better by comparing the power spectral density of different order PIM distortion.

通过对不同阶次的PIM功率谱进行比较，可以对不同阶次的干扰程度有更好的把握。

First, the methods and procedures of general three orders nonlinear identification are summarized and the results are frequency functions described by basic and high order spectral density functions and frequency response functions.

得到的结果是用基本的和高阶的谱密度函数以及基本的和高阶的频率响应函数表示的频率函数。

It means to recognize periodicity by analyzing the spectral density of periodically variable sequence, then to judge the measured period true or false through the statistical examination of Fisher's Kappa and Bartlett's Kolmogorovsmirnov.

第三节"波动周期的模型测定法"以"收入—支出"结构和"需求导向"为基本构架，通过建立中国宏观经济波动模型来测定宏观经济内生变量波动的周期长度，这种通过解析思路测定经济变量波动周期的方法，具有理论支撑，其科学性、可信性是显而易见的。

Road irregularity, as a stationary stochastic process, is generally illustrated by the power spectral density in frequency domain.

作为随机过程的车辆道路不平度高程，通用的模拟方法是频域模型－道路不平度功率谱密度。

This paper focus on some topics described as following based on the summarizer of:(1) Feature extraction of the EEGAnalyzing the origin, the mechanism and the framework of the EEG and using the power spectral density, AR model parameter, band power and the wavelet entropy as the features of the EEG recorded during imagination of hand movements.

本文在综述国内外研究现状的基础上对基于脑电信号的意识任务的识别进行了以下几个方面的研究讨论：(1)提取脑电信号的多个特征量对EEG信号的来源，产生机理，结构特征等进行分析，运用经典功率谱估计，AR模型功率谱估计，AR模型参数，信号能量，小波熵等多种方法对想象左右手动作的脑电信号进行特征提取，并比较其性能。

According to by the time series estimate power spectral density\'s periodogram law principle,the research adopts five level of orbital power spectra which US Federal railway Administrative bureau FRA proposed;then,through the Fourier inverse transformation,the orbital not smooth time domain samples are obtained, which determine the track irregularity peak-to-peak value and the corresponding wave length; on the basis of the research,the influence of the wheel track dynamic contact force are considered.Based on the orbital roadbed coefficient\'s definition,computation model is established to solve the roadbed equispaced spring constant,and the roadbed uniform spring stiffness is obtained by using the numerical simulation method.Finally,based on the Matlab procedure platform,the computational procedure is established,and the load time interval caused by the moving train acts on the roadbed is obtained.

根据由时间序列估计功率谱密度的周期图法原理，采用美国联邦铁路管理局FRA提出的五级轨道功率谱，通过Fourier逆变换得到轨道不平顺的时域样本，确定了轨道不平顺的幅值及对应的波长，以此为基础考虑轮轨动态接触力的影响；基于轨道路基系数的定义建立了求解路基均布弹簧刚度的计算模型，采用数值模拟得到了路基均布弹簧刚度；最后，基于Matlab程序平台编制了计算程序，得到了运行列车作用到路基上的荷载时程。

A narrowband interference has a greater power spectral density. Thus it will bring more strong devastation to the DSSS system than a broadband one does.So it is difficult for DSSS system to ensure a high quality of communication by itself when strong interference exists, even communication may be intermitted.

窄带干扰(Narrow-Band Interference，NBI)由于其功率谱密度比宽带干扰高得多，所以它对DSSS系统的破坏性更强，当有强窄带干扰存在时仅靠系统自身的抗干扰能力很难保证系统高质量的通信，甚至可能造成系统通信中断。

Fα power spectral density of the cardiac QRS complex is not associated with a fractal Purkinje system. Biophys J.

His-Purkinje系统的分形特征的形态学基础与心电信号表观之间有何关系的问题抗生素尚待进一步春季研究。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。