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30 results about "Entropy estimation" patented technology

In various science/engineering applications, such as independent component analysis, image analysis, genetic analysis, speech recognition, manifold learning, evaluation of the status of biological systems and time delay estimation it is useful to estimate the differential entropy of a system or process, given some observations.

Converter transformer tap switch condition monitoring system and non-stationary signal spectrum estimation method

The invention discloses a converter transformer tap switch condition monitoring system and a non-stationary signal spectrum estimation method. The system comprises a vibration signal sensor which is disposed on a housing of a transformer and is used for monitoring the operation process of a converter transformer tap switch; a digital filter for filtering noise waves; and a vibration data collection function module which is used for eliminating various types of signal noises. The method employs a maximum entropy-spectrum method, carries out solving of data outside a known limited data autocorrelation array through employing an extrapolation method under the condition of the maximum information entropy, and estimates the power spectrum density of a to-be-detected signal. The method achieves the estimation of the tap switch under the non-intruding detection, achieves the system inspection of the converter transformer tap switch, can reduce the incidence rate of faults in two preset correction periods, and employs the modern spectrum estimation method of maximum entropy estimation for the spectrum estimation of a non-stationary signal of an isolation switch, so as to further improve the analysis precision and accuracy.
Owner:STATE GRID CORP OF CHINA +2

Constant-depth-tooth bevel gear fault diagnosis method based on modified cepstrum

InactiveCN103234750AAccurate extractionTo achieve the purpose of fault diagnosisMachine gearing/transmission testingEngineeringMATLAB
The invention discloses a constant-depth-tooth bevel gear fault diagnosis method based on modified cepstrum and belongs to the technical field of fault diagnosis. The method includes: firstly, measuring a constant-depth-tooth bevel gear box by an acceleration sensor to acquire gear acceleration vibration signals to be analyzed; secondly, introducing the acquired signals to MATLAB (matrix laboratory) to obtain original signals, and subjecting the original signals to Fourier transform and logarithmic transformation to obtain a log power spectrum; thirdly, calculating maximum entropy of the log power spectrum by maximum entropy estimation algorithm; fourthly, drawing a maximum entropy spectrogram (namely a modified cepstrum diagram) of the log power spectrum by MATLAB, and accurately extracting gear fault feature information according to amplitude distribution in the modified cepstrum diagram. The method is an effective fault feature information extraction method, is applicable to fault diagnosis for constant-depth-tooth bevel gears, and is available for quickly and accurately extracting fault feature frequency to finally allow for fault diagnosis on the gears. The method is novel for the fault diagnosis and feature extraction for constant-depth-tooth bevel gears, and is effectively referable for composite fault diagnosis techniques for gears and other rotating machines.
Owner:BEIJING UNIV OF TECH

Human body meridian point positioning method based on electrocardiosignal intelligent information processing

The invention discloses a human body meridian point positioning method based on electrocardiosignal intelligent information processing. The method comprises the following steps of: selecting any one meridian, which has an acupuncture point needing to be determined, in human body meridians, selecting an area with a diameter being 3cm on skin where the acupuncture point needs to be positioned, dividing the area by adopting a network structure, taking meshes in the network structure as test points, and adopting a physiological signal acquisition instrument to acquire an electrocardiosignal of each test point obtained according to a bipolar limb lead method standard I; then, carrying out three-level decomposition on each electrocardiosignal of each test point by adopting a dbl wavelet packet, reconstructing each decomposed signal at single scale, carrying out entropy estimation on each reconstructed single signal, and adopting an entropy estimation value as an energy characteristic value of each test point of the acupuncture point; and carrying out division on acupuncture point data and non-acupuncture point data through adopting a hierarchical-K means hybrid clustering method so as to obtain an accurate position of the needed acupuncture point.
Owner:SHANGHAI NORMAL UNIVERSITY

Human body meridian point positioning method based on genetic cluster

The invention discloses a human body meridian point positioning method based on a genetic cluster. The method comprises the following steps of: selecting any one meridian, which has an acupuncture point needing to be determined, in human body meridians, wherein a signal generator is respectively connected with a stimulation point and a ground point on the meridian through silver electrodes, and sending a stimulation signal; selecting an area with a diameter being 3cm on skin where the acupuncture point needs to be positioned, dividing the area by adopting a network structure, taking meshes in the network structure as test points, and adopting a signal collector to monitor response signals of the test points; carrying out three-level decomposition on each response signal of each test point by adopting a dbl wavelet packet, reconstructing each decomposed signal at single scale, carrying out entropy estimation on each reconstructed single signal, and adopting an entropy estimation value as an energy characteristic value of each test point of the acupuncture point; and taking an obtained entropy energy characteristic vector of each response signal of each test point as a sample, carrying out clustering division on energy through the genetic cluster, and accurately positioning the acupuncture point of the meridian.
Owner:SHANGHAI NORMAL UNIVERSITY

Human body meridian point positioning method based on genetic cluster

The invention discloses a human body meridian point positioning method based on a genetic cluster. The method comprises the following steps of: selecting any one meridian, which has an acupuncture point needing to be determined, in human body meridians, wherein a signal generator is respectively connected with a stimulation point and a ground point on the meridian through silver electrodes, and sending a stimulation signal; selecting an area with a diameter being 3cm on skin where the acupuncture point needs to be positioned, dividing the area by adopting a network structure, taking meshes in the network structure as test points, and adopting a signal collector to monitor response signals of the test points; carrying out three-level decomposition on each response signal of each test point by adopting a dbl wavelet packet, reconstructing each decomposed signal at single scale, carrying out entropy estimation on each reconstructed single signal, and adopting an entropy estimation value as an energy characteristic value of each test point of the acupuncture point; and taking an obtained entropy energy characteristic vector of each response signal of each test point as a sample, carrying out clustering division on energy through the genetic cluster, and accurately positioning the acupuncture point of the meridian.
Owner:SHANGHAI NORMAL UNIVERSITY

An Evaluation Method of Assembly Contact Stress Distribution Based on Entropy Theory

ActiveCN106354942BPrecise and specific representationLittle influence on assembly accuracyGeometric CADDesign optimisation/simulationStress distributionAlgorithm
The invention discloses an entropy theory based assembly contact stress distribution assessment method which includes the steps of firstly, building a measurement coordinate system and a three-dimensional solid model to a to-be-tested part, subjecting the three-dimensional solid model to finite element cell meshing, and calculating strain energy density of each cell; secondly, calculating the overall entropy estimate value, the overall maximum entropy, the overall normalized entropy value Hs according to the strain energy density of each cell; thirdly, judging whether Hs is greater than or equal to the set threshold value, if so, then taking Hs as an assessment index to assess assembly stress distribution uniformity of surfaces of the to-be-tested part, and if not, then going to the next step; fourthly, building multiple sections perpendicular to the Z-axis of the measurement coordinate system; fifthly, searching a section with convex hulls of which quantity and area accounting for the maximum ratio to the surface area of the to-be-tested part, and calculating the convex hull height entropy estimate value, the convex hull height maximum entropy, and the convex hull normalized entropy value Hcs; sixthly, building the assessment index Ec that is equal to AHS + BHCS; and finally assessing the assembly stress distribution uniformity of the surfaces of the to-be-tested part according to the assessment index Ec.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

Atrial fibrillation detection device and storage medium

The present invention provides an atrial fibrillation detection device and a storage medium. The atrial fibrillation detection device includes: an extraction module for extracting P wave waveform information and QRS wave waveform information in ECG signals; a first determination module connected to the extraction module , used to determine the P wave change characteristics according to the P wave waveform information; the second determination module is connected to the extraction module and used to determine the PR interval change characteristics according to the QRS wave waveform information; the third determination module is connected to the extraction module for Determine the RR interval change characteristics according to the QRS wave waveform information; the calculation module is connected with the third determination module, and is used to calculate the information entropy of the RR interval change characteristics by using the entropy estimation method; the fourth determination module is connected with the first determination module and the second determination module. 2. The determination module is connected with the calculation module, and is used to determine whether the electrocardiographic signal is atrial fibrillation according to the change characteristics of the P wave, the change characteristics of the PR interval, information entropy and a preset classification model. The invention can improve the robustness of atrial fibrillation detection.
Owner:GUANGZHOU SHIYUAN ELECTRONICS CO LTD
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