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1.
According to non-Gaussianity and randomness of the Pulse Signals, the bispectrum estimation is used to analyze the signals for the purpose of extracting the unusual information of the signals of-the drug abusers and educing the judgment of how to distinguish drug abusers from healthy persons. The phase of bispectrum carries the important feature information in signal processing. The feature vector of the average phase information based on the indirect nonparametric bispectrum estimation is extracted and used to analyze the Pulse Signals of 15 heroin addicts and 15 healthy persons. It is found that the average phase Ph of heroin addicts on a specified frequency region is generally lower than that of healthy persons. Using the average phase Ph as characteristic parameter, a critical parameter is determined that is used to classify heroin addicts and healthy persons. Thus, all of the 15 healthy addicts are identified. Only one heroin person is misjudged. Experiment results of classification show that the method is feasible and effective. 相似文献
2.
Extracting features from biomedical signals to provide some decision support for medical diagnoses is an important aspect in the development of biomedical engineering.Analyzing power spectra of pulse signals for 15 heroin addicts and 15 healthy persons and calculating the power distributions on specified frequency bands for every power spectrum based on spectral estimation in this paper,we find that the significant difference of power distributions exists between the heroin addicts and the healthy persons.A primary criterion is also obtained,upon which the 13 cases of 15 heroin addicts are identified.The research result of this paper shows that the frequency domain analysis for pulse signals of heroin addicts is really an effective method. 相似文献
3.
The pulse sense of PVDF is used to collection pulse signals of subjects into computer and store them in data file style. The author select a series of pulse signals randomly which contains 40 consecutive cardiac cycles of subject and using a modern spectrum analysis method to estimate the power spectrum of data in every cardiac cycle.An average power spectrum is obtained through averaging such 40 power spectra. It is found that the significant difference of power distribution exists between the heroin addicts and the healthy person. The frequency axis of average power spectrum. Calculating the power distributions on specified frequency bands of the average power spectrum for every subject is carved up.A primary criterion is obtained. The above criterion is applied to 30 subjects including 15 heroin addicts and 15 healthy persons. The correctness of classifying heroin addicts and healthy persons arrives 93.3%.The result shows that the modern spectrum analysis method is really an effective measure to analyze pulse abnormalities of heroin addicts. 相似文献
4.
The most significant difference between the human pulse signals collected from heroin druggers and healthy persons is at their amplitude waveforms as time functions. That is, the amplitude values and change rates of two types of signals, within a particular time range, appear different features. However, the partial components of the scaling and wavelet coefficients of the pulse signals obtained by using wavelet transform can reveal such key features. The pulse signals of 15 heroin druggers and 15 healthy persons are analyzed through using the muhiresolution analysis of wavelet transform. By using db2 orthogonal wavelet, every pulse signal is decomposed into three levels and the absolute values of the sixth component of scaling coefficients and the second component of the wavelet coefficients in the third level are combined to form a feature vector. A probabilistic neural network with good detection performance is successfully designed for automatically detecting 30 feature vectors. During the network design, 20 feature vectors are used as training samples. The remained 10 feature vectors are used as testing samples. Based on these steps, 15 heroin druggers and 15 healthy persons are all correctly identified. In other words, the detection rate arrives at 100%. druggers. 相似文献
5.
According to the randomness of human pulse signals,the multiresolution analysis of the wavelet transform is used to analyze such signals.Its purpose is to extract the abnormal information from the pulse signals of heroin druggers and to obtain the primary judgment criterion which can be used to identify druggers from healthy persons.The scale spectrum based on the wavelet transform of pulse signals carries the important characteristic information of the health situation of human body.The pulse signals of 15 heroin druggers and 15 healthy persons are analyzed and the scale spectrum and the total signal energy of every signal are extracted.It is found that the ratio between the sum(i.e.,scale-wavelet energy) of the scale spectrum in a specific scale-time region and the total signal energy for heroin druggers is generally higher than that of healthy persons.Using the percentage of the ratio between the scale-wavelet energy in the specific scale-time region and the total signal energy as characteristic parameter,a critical parameter is determined that is used to classify heroin druggers and healthy persons.Thus,all of the 15 healthy persons are identified correctly from 30 subjects.Only two heroin persons are misjudged.The experiment results of classification show that the method presented is feasible and effective for detecting the pulse abnormalities of heroin druggers. 相似文献
6.
In this paper,the parametric equation of a hydraulic excavator workwpace areestablished by using the spatial mechanism theory of robot.Characteristic points of the workspaceboundary are searched by the optimization procedure and the calculate formula of area of theworkspace longitudinal section is found. 相似文献
7.
A novel channel estimation algorithm is proposed for MB OFDM Ultra Wide Band systems based on tap detecting by exploiting the sparse property of channel impulse response. The channel parameters are estimated using the DFT algorithm based on cyclic convolution property of the receive signals. The nonzero taps are detected by exploiting the matching pursuit(MP) algorithm. The new estimated channel parameters are obtained by forcing the zero taps to zeros. Simulation results demonstrate that it has better MSE (mean square error) performance for the four channels proposed by IEEE. Especially for CM1 and CM2 channels, the performance of the algorithm has been greatly improved. 相似文献
8.
The finite element model is developed for the multi stage planetary gearbox housing in shield tunnelling machine (STM), and the the eigenvalue problem is solved by using block Lanczos method, and then the low order natural frequencies and corresponding modes are extracted. Based on the theory of experimental modal analysis, the modal testing is made for the gearbox housing by pulse excitation method. The least squares complex frequency domain (LSCF) estimation method is used to analyze the modal data, and the natural characteristics of housing is obtained. According to the modal assurance criterion (MAC), the experimental modal parameters are validated. Modal analysis shows that the experimental data is coincided with analytical results, which indicates the accuracy of the theoretical model and testing method. The coupling sympathetic vibration is disappearing between the gears train and housing, the local vibration is large at the high speed side of gearbox housing, and the torsional mode is outstanding under operating condition. The research results provide theoretical basis and experimental support for the structural optimization of the gearbox of STM. 相似文献
9.
《Soil Technology》1992,5(2):143-149
When Richard's flow equation was solved numerically two parameter estimation procedures were assessed for their applicability in the estimation of parameters of soil hydraulic characteristics, the water retention and hydraulic conductivity functions, and saturated hydraulic conductivity. The estimation procedures assessed were Taylor expansion and Marquardt (1963). The model simulated soil water content and pressure head profiles, obtained with the optimized estimates for the parameters from either method, agreed close with the corresponding measured profiles. Similar trends were observed for the water retention curve. The unsaturated hydraulic conductivities calculated, using the measured values in water content and pressure head agreed with those obtained using the established hydraulic conductivity functions. The results show that the techniques developed in this study were satisfactory to predict sufficiently accurate the hydraulic characteristics required to describe unsaturated flow of water in soil. The techniques appear promising, becuase the auxilliary information, soil water content, required for the estimation of hydraulic characteristics was minimal and relatively easy to collect. 相似文献
10.
For using smooth probability density function to retrieve wavelet coefficient histogram and coefficient module histogram, parameter estimation is complicated, which results in hard to retrieve the texture features effectively. A texture image retrieval method using double density dual tree complex wavelet Refined Histogram(RH) model is proposed. By analyzing the principle of double density dual tree complex wavelet transform (DD-DT CWT) and the inherent relationship between the nonuniform quantizer and RH model, the RH model is extended to retrieve the DD-DT CWT coefficient and the coefficient histogram feature. The RH is used to model the magnitude of the DD-DT CWT. The RH parameters for all magnitude of complex coefficients forms the signature of an image. Image similarity measurement is accomplished by using the Kullback-Leibler divergences . The proposed method combines the advantages of the RH model and the shift-invariant DD-DT CWT. The experiment results show that the proposed methods yields higher retrieval rate than using the General Gaussian Density(GGD) model to fit with the real part or imaginary part of coefficients, and is better than using the Gamma PDF to fit with the magnitude of coefficients. 相似文献
11.
冬小麦不同株型品种光谱响应及株型识别方法研究 总被引：5，自引：0，他引：5
以直立和平展2种株型的冬小麦品种为材料，研究了它们的光谱响应以及田间植被覆盖度的差异，探讨了利用冠层光谱反射率、光谱特征参量NDVI及植被覆盖度识别小麦株型的方法。结果表明，（1）小麦不同株型品种在近红外波段（700～1300 nm）光谱反射率有明显差异，生育前期平展型品种高于直立型品种，并以拔节期的差异为最显著，随着生育进程差异逐渐变小。拔节期是进行株型识别的最佳时期，并且此期冠层的敏感波段680 nm和760～900 nm的反射率在2种株型品种之间差异明显。（2）小麦冠层叶面积指数（LAI）与归一化差异植被指数NDVI(680,890)呈正相关，并且不同生育阶段其相关程度有差异，这是利用NDVI和植被覆盖度(COV)识别不同株型的基础。（3）相同COV条件下，直立型品种的NDVI高于平展型品种的NDVI，并且随着COV的增加，差异逐渐变小，二者的变化关系体现了直立型品种株型紧凑和平展型品种株型披散的特点，利用NDVI和COV的关系可以对株型进行识别，以小麦拔节期为最佳识别阶段，此期2种株型品种的NDVI具有显著差异（P＜0.05）。 相似文献
12.
针对目前位移传感器很难直接测得木结构或木构件在转动中产生较大绝对水平位移的问题,研制了量程为±500 mm的电阻应变式位移传感器（WD位移传感器）,应用正交试验法分析WD位移传感器的影响因素,并对其进行设计与制作,拟合了传感器在不同量程下应变位移的分段函数关系,通过计算得出了WD位移传感器的6种静态参数指标。试验结果表明,WD位移传感器克服了传统电阻应变式位移传感器量程小的问题,解决了木结构或木构件发生非直线运动很难直接测得绝对水平位移的问题,且各静态参数指标良好。 相似文献
13.
The two methods of estimating parameter in computable general equilibrium(CGE) model are introduced and compared:the calibration procedure and econometric estimation. The conclusions are:the estimation of parameter in CGE model must use the calibration procedure coupled with the econometric estimation method;the elasticity of output with respect to labor input,the marginal expenditure share for households and price elasticity of export demand are estimated by econometric estimation method;and other parameters of the CGE model can be get by calibration procedure. 相似文献
14.
Wang Jianping Mi Linshu Chen Gang 《保鲜与加工》1993,(6):32-37
The angular frequency and decaying constant of each copmonect for the
transient waveform in power systems were obtained by using the discrete Fourier transform; the amplitude and phase angle were calculated in the linear curve fitting method. And all of the parameters obtained above were treated in an unified optimization by using the curve fitting optimization of the least square method of general nonlinear funcrion so as to get the results of waveform analysis. Two examples are included. 相似文献
15.
在综合分析现有水平荷载作用下桩基分析方法的基础上,建立了考虑桩侧土体受力状态的斜坡刚性桩力学模型;根据极限平衡原理,建立横向荷载作用下斜坡刚性桩弯矩和应力平衡方程;引入考虑斜坡影响的p-y曲线方法,提出了综合考虑桩侧土体极限承载力与水平抗力系数沿深度呈线性增加的侧向极限承载力与土体抗力承载力系数计算方法,同时,将该方法应用于计算实例,通过与已有有限元和理论计算方法对比分析,计算结果验证了本文方法的合理性与可行性;并利用该方法,分析了斜坡坡角、桩土接触面系数以及地基水平抗力系数对斜坡刚性桩承载特性的影响因素。分析表明:斜坡的坡角、桩土接触面系数对侧向荷载作用下斜坡刚性桩的荷载位移曲线影响明显,而桩侧土的抗力系数对侧向荷载作用下斜坡刚性桩的荷载位移曲线影响不明显。 相似文献
16.
The sampling speed for the ultra wide band (UWB) channel is too high to realize with the existing sampling technology. To solve the problem, a novel blind channel estimation algorithm was presented based on the theory of compressive sensing. Firstly, some measurements are obtained which are linear combinations of the received signals multiplied by a random incoherent measurement matrix. Then, the mathematical model is established by exploiting the first statistics of the measurements. Finally, the orthogonal matching pursuit (OMP) algorithm is utilized to get the estimating channel parameters. With the proposed algorithm, the number of the measurements need for channel estimation is much smaller than that of the samples needed for the existing algorithms, which reduces the ADC resources greatly. The simulation result shows that the estimation performance of the algorithm is good, while the bit error rate (BER) is only 2~3dB higher than that of the exact channel. 相似文献
17.
In binary phase diagram there are many stable compounds. Hereby a new method for calculating activities of compounds from binary phase diagram involved stable compounds is presented. Based on the available formula for calculating activities in binary phase diagram, the activities of the two pure components are gained. And the balance constant K~0 can be obtained from mass action law. Thereby, the activities of stable compounds are obtained from the activities of the two pure components. By using this method, the activities of stable compounds in In-Sb system are obtained. It proves that this method is feasible. 相似文献
18.
The mass flowrate of Coriolis mass flowmeter in practical application has slow changes with time. To solve the problem, an improved time-varying signal model whose frequency, amplitude and phase are time-varying based on the random walk model is established firstly. A new algorithm of adaptive notch filter with the capability of tracking frequency variation is applied to filter the sensor output signal of Coriolis mass flowmeter and its frequency is calculated next. An adaptive line enhancer based on the mentioned notch filter extracts fundamental frequency signal from noisy data. Then, by short window intercepting, the revised sliding DTFT recursive algorithm is introduced to calculate the real-time phase difference between two enhanced signals. With the frequency and phase difference obtained, the time interval between the two signals is calculated and then the mass flowrate is derived. The simulations and field test results show that the proposed method can not only track the change of frequency and phase, but also ensure the calculation accuracy when measuring small phase difference. The computational load of the algorithm is simple so that it can be applied to real-time signal processing for Coriolis mass flowmeter. 相似文献
19.
A novel signal processing method for Coriolis mass flowmeter is proposed based on time-varying signal model. First, an adaptive lattice notch filter is applied to filter the output signal, whose frequency, amplitude and phase are time-varying based on the random walk model, of Coriolis mass flowmeter to get its frequency and enhanced signal. Then, by short window intercepting, the DTFT algorithm with negative frequency contribution is introduced to calculate the real-time phase difference between two enhanced signals. With the frequency and the phase difference, the time interval between two signals is calculated. Simulation results show that the proposed method is efficient. Furthermore, the computation of algorithms is simple so that it can be applied to real-time signal processing for Coriolis mass flowmeter. 相似文献
20.
In order to solve the problem that the choice of acoustic emission (AE) parameters in concrete detection are determined only by experience, several tests were conducted. Through lead-breaking and stimulant loading tests, the reasonable value of threshold at which noise can be efficiently insulated was obtained. Through lead-breaking tests, time parameters (PDT, HDT, HLT) which fit concrete samples were obtained. The velocity and attenuation of AE signals in concrete also were measured through lead-breaking tests. This method of ascertaining detection parameters by testing is practical for AE detection in concrete structures. 相似文献