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151 results about "Approximate entropy" patented technology

In statistics, an approximate entropy (ApEn) is a technique used to quantify the amount of regularity and the unpredictability of fluctuations over time-series data.

Method for extracting and fusing time, frequency and space domain multi-parameter electroencephalogram characters

The invention relates to a method for extracting and fusing time, frequency and space domain multi-parameter electroencephalogram characters, which comprises the following steps: 1) collecting an electroencephalogram signal; 2) performing data pre-processing on the electroencephalogram signal; 3) extracting Kc complexity, approximate entropy and wavelet entropy from the pre-processed data; 4) on the basis of AMUSE algorithm, acquiring an electroencephalogram singular value decomposition matrix parameter; 5) performing character selection on the time, frequency and space domain character parameters for the extracted Kc complexity, approximate entropy, wavelet entropy and electroencephalogram singular value decomposition matrix parameters; 6) utilizing a SVM classifier to fuse and classify the four parameters of the time, frequency and space domains after the character selection. According to the method provided by the invention, the Kc complexity, the approximate entropy, the wavelet entropy and the electroencephalogram singular value decomposition matrix parameter can be selected for comprehensively presenting electroencephalogram character information, and then subsequent effective fusion is performed, so that effective support and help can be supplied to early diagnosis assessment for the brain functional disordered diseases, such as, Alzheimer disease, mild cognitive impairment, and the like.
Owner:秦皇岛市惠斯安普医学系统股份有限公司 +1

Single phase ground fault section locating method in small current grounding system

The invention provides a single phase ground fault section locating method in a small current grounding system, which includes the following steps: step 1, recording the zero mode voltage and the zero mode current of the previous period and the next period of the single phase ground fault time when the single phase ground fault occurs to the small current grounding system; step 2, selecting the highest frequency intrinsic mode function component after decomposing the transient zero mode power pure fault component of the single phase ground fault time through empirical mode decomposition; step 3, obtaining the approximate entropy proportionality factor of the highest frequency intrinsic mode function component of each detecting section through the approximate entropy value of the high frequency intrinsic mode function component of each detecting section; and step 4, comparing the approximate entropy proportionality factor of the highest frequency intrinsic mode function component of each detecting section with the preset first threshold in the main station, so as to find out the section with the single phase ground fault. The single phase ground fault section locating method has the characteristics of high detecting precision and universality, and can be widely applied to the power system.
Owner:HENAN POLYTECHNIC UNIV

Device and method for detecting attention focusing degree based on analysis of heart rate variability

The invention discloses a device and a method for detecting attention focusing degree based on the analysis of heart rate variability, mainly solving the problems of large interference and inconvenient testing of reference signals for attention judgment in the prior art. The method comprises the following testing steps: acquiring original electrocardiographic digital signals according to a MV5 lead mode; filtering the interference in the original electrocardiographic digital signals, extracting the position of a R wave and calculating heart rate variability signals; integrating and segmentingthe heart rate variability signals; performing empirical mode decomposition on each segment of the heart rate variability signals; calculating the approximate entropy of the heart rate variability signals and intrinsic mode function component signals; training a neutral network by using the calculated approximate entropy as an input vector of a reverse transmit neural network algorithm, and determining the parameters of codes of a neutral network; and detecting the attention focusing degree of a subject by utilizing the trained neutral network and outputting the test result. The invention hasthe advantages of large reference signal strength, convenient test and high accuracy, and is used for testing the attention focusing degree of a human body.
Owner:XIDIAN UNIV

Method for quantitatively evaluating symptoms of tremor of patient with Parkinson's disease according to approximate entropy and cross approximate entropy

The invention provides a method for quantitatively evaluating the symptoms of tremor of a patient with Parkinson's disease according to the approximate entropy and the cross approximate entropy, belonging to the fields of health care and pattern recognition. The method is characterized by comprising the following steps of: collecting the data of specified tremor of the thumb, collecting the data of specified tremor of the index finger, and grading the specified tremor of the thumb and the specified tremor of the index finger according to a UPDRS (unified Parkinson's disease rating scale); preprocessing the data of tremor; separating a sample training set from a sample testing sample; calculating the approximate entropy and the cross approximate entropy of the data of tremor; constructing the model of a classifier, and verifying the effectiveness of a method. The regularity and the synchronization of the tremor of the patient with Parkinson's disease are disclosed effectively according to the approximate entropy and the cross approximate entropy, and the symptoms of tremor can be accurately and quantitatively classified according to the tremor amplitude, the tremor frequency and other characteristics of the patient. The method is used for objectively evaluating the symptoms of tremor of the patient with Parkinson's disease, and can be applied to the fields of treatment and rehabilitation assessment of the patient with Parkinson's disease and the like.
Owner:HEFEI INSTITUTES OF PHYSICAL SCIENCE - CHINESE ACAD OF SCI +1

ECG signal classifying method based on wavelet packet and approximate entropy

The invention discloses an ECG signal classifying method based on a wavelet packet and approximate entropy. The method comprises the steps that wavelet packet decomposition is conducted on preprocessed ECG signals, the wavelet packet coefficients of all nodes are extracted, and then the approximate entropy of all the wavelet packet coefficients is calculated; the obtained approximate entropy is used as a feature vector to be input into a support vector machine classifier, a particle swarm algorithm is used for seeking the optimal parameter of the support vector machine classifier, and various ECG signals are classified. Wavelet packet decomposition is an effective method for analyzing non-stationary signals. The approximate entropy can be used for obtaining stable estimation values only by a small amount of data, good noise-proof and anti-interference capacity is achieved, and the approximate entropy can both be used no mater what the signals are, stochastic or deterministic. According to the ECG signal classifying method, an algorithm for extracting feature vectors is simple, dimensionality reduction in a traditional method is of no need, the speed is high, consumed time is small, the classifying accuracy is high, and the ECG signal classifying method is suitable for an ECG automatic analysis auxiliary diagnosis system.
Owner:TIANJIN POLYTECHNIC UNIV

Dynamic weighted hybrid clustering algorithm based circuit breaker fault diagnosis method

The invention discloses a dynamic weighted hybrid clustering algorithm based circuit breaker fault diagnosis method. The method includes the following steps: (1) capturing the energy changes of mechanical drive during the operation of a circuit breaker by utilizing three-axis vibration and two-way sound signals, decomposing the signals through local mean, and extracting the approximate entropy ofeach PF component as the characteristic quantity of a circuit breaker vibration signal; (2) optimizing the initialized clustering center of fuzzy kernel clustering by utilizing the maximum density peak decision of a density peak clustering algorithm, and considering different influences of different characteristics and different samples on clustering results; (3) performing checking on a clustering number K through a cluster validity index MIA; (4) inputting correctly classified characteristics into a multi-level classifier of a support vector machine to perform training; and (5) finding the optimal parameter of the support vector machine through mesh generation, and inputting test data samples to perform final fault classification prediction so that classification accuracy rates can be obtained;. The method has advantaged of being fast in fault diagnosis speed and high in accuracy rate.
Owner:JIYUAN POWER SUPPLY COMPANY OF STATE GRID HENAN ELECTRIC POWER

Driving state recognition method based on approximate entropy template matching

The invention discloses a driving state recognition method based on approximate entropy template matching, and the method comprises the steps: 1, sample library building, wherein samples of one type in the sample library are a plurality of steering wheel turning angle signals in a normal driving state, and samples of the other type in the sample library are a plurality of steering wheel turning angle signals in a dangerous driving state; 2, road information segmentation based on the approximate entropy template matching: carrying out the call of a signal correction module based on the approximate entropy template matching to correct the steering wheel turning angle signals in the library sample, wherein the correction process of any one steering wheel turning angle signal is as follows: carrying out the EMD (Empirical Mode Decomposition), the effectiveness recognition of an intrinsic mode function component, and signal reconstruction; 3, feature extraction; 4, two-class model building and training; 4, driving state information collection and synchronous classification. The method is simple in steps, is reasonable in design, is easy and convenient to implement, is good in use effect, can accurately recognize the driving state of a driver simply and conveniently, and is high in recognition precision.
Owner:陕西智慧路衡电子科技有限公司

A denoising method of magnetotelluric signal based on noise discrimination

The invention discloses a magnetotelluric signal denoising method based on noise discrimination, which comprises the following steps: calculating approximate entropy and LZ complexity of each electromagnetic signal sample; using the approximate entropy, LZ complexity and class value of each electromagnetic signal sample to train the preset classification model to get the noise discrimination classification model; acquiring magnetotelluric signals to be processed, and performing noise screening on the magnetotelluric signals to be processed according to the noise screening classification modelto obtain electromagnetic signal segments with non-strong interference and electromagnetic signal segments with strong interference; combining the empirical mode decomposition of complementary set andwavelet threshold method, the strong disturbance electromagnetic signal being suppressed; the reconstructed magnetotelluric signal being obtained by combining the de-noising suppressed electromagnetic signal with the non-strong disturbance electromagnetic signal. The method of the invention can more accurately discriminate the data segments with strong interference and non-strong noise interference, retain the real magnetotelluric signal, and improve the denoising effect of the magnetotelluric signal.
Owner:HUNAN NORMAL UNIVERSITY

Rolling bearing health evaluation method based on local characteristic scale decomposition-approximate entropy and manifold distance

InactiveCN105973593AAvoid the disadvantage of large amount of calculationReduce endpoint effectsMachine bearings testingCharacter and pattern recognitionRolling-element bearingBearing vibration
The invention proposes a rolling bearing health evaluation method based on local characteristic scale decomposition-approximate entropy (APEn) and manifold distance. First, an original vibration signal is decomposed by LCD into a plurality of intrinsic scale components (ISCs); then, the approximate entropy of each ISC is calculated; and finally, the manifold distance between the approximate entropy of the ISCs and the approximate entropy of normal data is calculated, and the calculated manifold distance is normalized into confidence (CV) to express the health degree of a rolling bearing. The normal operation of rolling bearings is particularly important in the modern industrial complex mechanical system, so that rolling bearing performance evaluation is of great significance in prediction and health assessment of the mechanical system. However, as bearing vibration signals are nonlinear and unsteady, it is particularly difficult to accurately extract the characteristics of bearing vibration signals. Local characteristics of signals can be extracted accurately using the method proposed by the invention. Results show that the method proposed by the invention can be used to evaluate the health degree of rolling bearings effectively.
Owner:BEIHANG UNIV

Modulation signal classification method for cuckoo search-improved gray wolf optimizer-least square support vector machine

The invention discloses a modulation signal classification method for cuckoo search-improved gray wolf optimizer-least square support vector machine. The method selects a high-order cumulant and a local mean decomposition amount approximate entropy for the characteristic parameter of a modulation signal, and utilizes cuckoo search for the second update of the wolf position to optimize the two keyparameters of a least squares support vector machine model, namely, the penalty coefficient Gamma and the kernel parameter Sigma, so as to obtain the optimal kernel limit learning machine parameter value. The method reduces the influence of noise factor on the signal recognition result, makes up for the defects of under-envelope, over-envelope and boundary effects in the traditional modal empirical decomposition, and effectively improves the defect that the gray wolf optimization global searching ability is poor and is easy to fall into the local optimal solution in processing of high-dimensional data, compared with the original gray wolf optimization result by MATLAB simulation, is it proved that the method can intelligently classify the modulated signal more efficiently and accurately, and has a good application prospect.
Owner:NANJING UNIV OF POSTS & TELECOMM

Desert seismic signal denoising method based on VMD approximate entropy and multi-layer perceptron

ActiveCN108845352AAvoid settingSolve the defect that signal-to-noise separation cannot be achievedSeismic signal processingSignal-to-noise ratio (imaging)Noise removal
The invention relates to a desert seismic signal denoising method based on the VMD approximate entropy and a multi-layer perceptron and belongs to the field of geophysical technology. The two-dimensional desert seismic record is subjected to variational mode decomposition to obtain a series of eigenmode components, the approximate entropy of each eigenmode component is calculated, all the eigenmode components are respectively divided into an effective signal dominant component and a noise dominant component, a characteristic quantity is constructed through effective signal correlation, the characteristic quantity is inputted into the multi-layer perceptron for classification, the valid signal portion determined by the multi-layer perceptron classifier is reserved, the noise portion determined by the multi-layer perceptron classifier is removed, the noise dominant component is denoised through combining an autocorrelation coefficient with tzhe multi-layer perceptron, and lastly, desertseismic signal denoising is realized through reconstruction. The desert seismic signal denoising method is advantaged in that noise removal under strong noise and low signal to noise ratio conditionsis achieved, the desert seismic signal denoising method has fast speed, high accuracy and strong anti-interference ability, and denoising of desert seismic signals under low frequency and low SNR canbe realized.
Owner:JILIN UNIV

Water supply pipeline leakage identification method based on signal time-frequency characteristics and support vector machine

ActiveCN109284777AComprehensive detection effectAvoid problems with a high probability of misjudgmentCharacter and pattern recognitionSupport vector machineFeature set
The invention discloses a water supply pipeline leakage identification method based on signal time-frequency characteristics and support vector machine, belonging to the technical field of water leakage detection and positioning. The method includes: inputting a detected signal; performing feature extraction of the input signal; the extracted feature set is input to the optimized support vector machine, and the feature is recognized by the support vector machine. The support vector machine outputs a recognition result according to the input signal characteristics, and determines whether the signal is a leakage signal or a non-leakage signal. Based on the intrinsic mode function, approximate entropy and principal component analysis, three time-frequency characteristics of leakage signal areproposed by using its randomness and centralized frequency spectrum. Using these features to construct feature matrix as input of support vector machine, support vector machine is used as classifierto recognize the signal and output recognition results, thus solving the existing pipeline leak detection technology problems such as modeling difficulty coefficient is large, high misjudgment rate ishigh.
Owner:INNER MONGOLIA UNIVERSITY

Detection method of detection device for drainage pipeline blockage faults

ActiveCN107218518AOvercoming Disadvantages of Fault DetectionHighlight failure conditionsPipeline systemsCorrelation coefficientDecomposition
The invention discloses a detection method of a detection device for drainage pipeline blockage faults. The method comprises the steps that the detection device for the drainage pipeline blockage faults is arranged; a computer obtains a signal of a normal / blocked pipeline from the receiving end; acoustic response signals in two working conditions of a drainage pipeline are acquired; LMD decomposition is conducted on the acoustic response signals of the normal pipeline and the blocked pipeline; correlation coefficients of all PF components of the normal pipeline and an original signal and correlation coefficients of all PF components of the blocked pipeline and the original signal are calculated by adopting a Pearson correlation coefficient method, and each component of which the correlation coefficient exceeds 15% is taken as an effective PF component signal; energy entropy indexes, approximate entropy indexes and average acoustic pressure indexes of the effective PF components of the normal pipeline and the blocked pipeline are calculated to serve as a characteristic set; an optimal parameter of the characteristic set is sought through a K-CV method; the steps are repeated, and fault identification is conducted on other sections of the pipeline by adopting an SVM classifier with the trained parameter. According to the detection method, the detection procedure is conveniently conducted, and the accuracy and reliability of a detection result are improved.
Owner:KUNMING UNIV OF SCI & TECH

Water turbine tail water pipe dynamic characteristic extraction method

The invention relates to a water turbine tail water pipe dynamic characteristic extraction method. The method comprises the following steps that pressure fluctuation signals of a water turbine tail water pipe under three states of no vortex strip, vortex strips and serious vortex strips are collected by a field test which is carried out by a hydroelectric generating set; the collected pressure fluctuation signals are subjected to resample under the three states of the water turbine tail water pipe, and high-frequency interference in the pressure fluctuation signals is removed; the pressure fluctuation signals subjected to resample under the three states are resolved by adopting an intrinsic time-scale decomposition method, and a monotonous baseline vector and a plurality of intrinsic rotational components are obtained corresponding to the pressure fluctuation signals under the three states; the dynamic characteristics of the water turbine tail water pipe are extracted by the approximate entropy of the intrinsic rotational components, which is respectively obtained by calculation, of the water turbine tail water pipe under the three states. The water turbine tail water pipe dynamic characteristic extraction method has the advantages of efficiency, strong instantaneity and the like, and can be widely applied to the fields of running guarantee of the hydroelectric generating set.
Owner:CHINA INST OF WATER RESOURCES & HYDROPOWER RES
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