44 results about "Higher order moments" patented technology

A modulation identification method under an MIMO related channel based on a machine learning algorithm of the invention belongs to the field of communication. The method comprises the specific steps as follows: first, space-time coding is performed on each data flow of a communication transmitter, and code words are emitted out through Nt transmitting antennas; then, a correlation matrix (as shown in the description) of a receiver and a correlation matrix (as shown in the description) of the transmitter are received, and an MIMO channel matrix H is calculated; the received signal on each receiving antenna is calculated according to the MIMO channel matrix H and corrected; and finally, each receiving antenna extracts the features of the corresponding corrected signal, training test is performed on the extracted feature values, and a modulation identification mode to which a sample belongs is calculated. The advantages are as follows: the method has strong robustness and generalization ability to non-Gaussian channels, and modulation system identification under a more complex environment can be realized through parameter iteration; and by extracting high-order moment and high-order cumulant features, the signal feature difference is obvious under high signal-to-noise ratio, and the classification of a machine learning algorithm is facilitated.

The invention discloses a temperature measurement method based on magnetic nano magnetization intensity. The temperature measurement method is characterized in that the effect of the particle size distribution of a magnetic nano reagent on temperature measurement is considered; accurate temperature measurement is realized in the presence of unknown magnetic nano particle size distribution; when a direct current magnetic field is applied on the magnetic nano reagent, magnetization intensity signals under different magnetic field intensity excitations are detected; the relationship among magnetic nano particle magnetization intensity, temperature, concentration and particle size high order moments is used to accurately solve the temperature; when an alternating current magnetic field is applied on the magnetic nano reagent, an alternating current magnetization intensity signal is acquired, and first and third harmonic amplitudes are detected; and the relationship among first and third harmonic amplitudes of alternating current magnetization intensity, temperature, concentration and particle size high order moments is used to accurately solve the temperature. According to the invention, the temperature measurement method based on single particle size and magnetic nano magnetization intensity is optimized and improved; and from experimental data, the temperature error of the magnetic nano temperature measurement optimized method is less than 0.2K.

The present invention discloses a large-scale MIMO system low-complexity polynomial expansion matrix inversion method and the application of the method in an uplink detection method, a downlink pre-coding method and link adaptation calculation. According to the method, based on the operator-valued free probability theory derivation, the deterministic equity of a channel matrix high-order moment is obtained, the approximation polynomial coefficient needed by the polynomial expansion matrix inversion method is calculated further, a signal processing method is easy to calculate, the method can be used in a large-scale multi-input multi-output system with a user with multiple antennas, and a minimal performance loss is obtained while the computational complexity is low.

The invention relates to a wind power climbing event probability scene prediction method. According to the method, distribution characteristic consistency and time sequence characteristic consistency are achieved through building of a multi-objective fitness function of a cumulative density function and a high-order moment autocorrelation function. On the basis of a genetic algorithm of the multi-objective fitness function, iterative optimization is conducted on probability generation model parameters to obtain a large number of prediction scenes, and climbing event probability characteristics excavated from scene capture zones are used for evaluating the prediction method. Actual data of some aboard wind field are selected for conducting example calculation and statistical analysis, the result shows that the statistical result of the multi-objective function is more accurate than that of a single-objective function, the probability scene prediction method can accurately estimate the characteristic quantity of a climbing event, the correctness of the method is proved, and the method can provide guidance for a probability scene generation method and a climbing event prediction model.

The invention provides a 16QAM (Quadrature Amplitude Modulation) carrier synchronization and loop synchronization locking detection method. Through utilization of the method, the influence of signal amplitude on 16QAM carrier synchronization and loop synchronization locking detection can be clearly eliminated. The technical scheme provided by the invention is realized through the following processthat carrier synchronized data is divided into I and Q ways; high frequency components in the data are filtered through lowpass filters; the filtered data is sent to a carrier synchronization lockingdetector for carrier synchronization locking detection; the carrier synchronization locking detector compares normalized high order moment calculation values of the I and Q ways with a detection threshold at each moment and judges whether a carrier synchronization loop is locked or unlocked; an indicator drives an FPGA reset signal to reset a phase-locked loop of the carrier synchronization loop;digital intermediate frequency signal carriers are demodulated to a zero intermediate frequency module through I and Q demodulators, so the carrier synchronization loop is locked on an accurate frequency again; zero intermediate frequency signals are sent to a rear-end clock recovery loop module for clock recovery; and judgment is carried out by a judgment module, thereby acquiring a receiving sequence.

The invention discloses a full-band antenna array and radome integrated simulation method. The method comprises the following steps: establishing a geometric model of an antenna and a radome; Importing the mdoel into a material library; Performing grid division on the surface of the geometric model by adopting a high-order moment method based on a high-order basis function; Setting an excitation field; Calculating a near-far field value and surface current data by adopting a parallel solving method based on a block matrix; Extracting electrical performance parameters of the antenna cover; Andoptimizing the electrical performance parameters of the antenna cover until the electrical performance parameters meet the design requirements. On one hand, the number of unknown quantities generatedby the moment method is effectively reduced by adopting the high-order moment method based on the high-order basis function; on the other hand, the parallel solving method based on the partitioning matrix is used for improving the calculation scale and the calculation speed of the moment method, and the bottleneck problem that the moment method consumes time and memory is effectively solved.

The invention provides a deformation conformal array antenna modeling method based on a high-order moment method, and aims to solve the technical problem that a deformation conformal array antenna calculation model built in the prior art is poor in accuracy. The method comprises the following implementation steps: obtaining a deformation curve function Z(x) of a to-be-constructed deformation conformal array antenna calculation model; establishing an undeformed conformal array antenna calculation model based on a high-order moment method; obtaining coordinates of projection points of N vertexeson Z(x) in the undeformed conformal array antenna calculation model; and constructing a deformation conformal array antenna calculation model. Projection points of all vertexes in an undeformed conformal array antenna calculation model on Z(x) are connected, a deformation conformal array antenna calculation model which is tightly connected among the grids is constructed; and the side length of each grid in the high-order moment method adaptive quadrilateral subdivision grid is small, and the linear distance of each connected projection point can be equal to the curve length of the projectionpoints on Z (x), so that the transition of the calculation model is smooth, and the accuracy of the calculation model is effectively improved.

The invention belongs to the technical field of music search based on contents, in particular to an audio-frequency fingerprint method of a compressed domain based on Zernike moment. The invention combines the frequency and time information of the modified discrete cosine transform coefficient (the MDCT coefficient) of the data of the compressed domain of an MP3 and some properties of the Zernike moment skillfully, such as low-order moment representing the integral properties of a signal and high-order moment representing the detailed properties of the signal; and the Zernike moment has the invariable properties of rotation, scaling and translation, so that the fingerprint of the audio-frequency compressed domain which is finally formed can resist the processing of a plurality of signals of a time domain robustly and resists the processing of the signals of the time domain slightly.

The invention discloses a method for decomposing an out-of-core area based on a parallel high-order moment method. The method comprises the following steps of according to the actual characteristics of a solving objective, separating into n subareas, and modeling; for discontinuity, stopping to extend to the adjacent area; for continuity, respectively sectioning each subarea, and extracting model information; for each subarea, respectively solving by the high-order moment method, introducing an out-of-core solving technique when an impedance matrix is filled, and storing data by a hard disc; when the structures of the subareas are the same, filling at one time, and reusing in the subsequent iteration process; initiating the current value, setting one iteration error range and the maximum iteration times, sequentially iterating, solving the current of each subarea, and further solving the field distribution of the whole area. The method has the advantage that the accuracy, realizability and reliability are higher.

The present invention proposes a tape carrier antenna optimization method based on higher-order moment method region decomposition, in order to realize simulation and optimization of metallic or dielectric metal mixed tape carrier antenna, and improve optimization efficiency. The method comprises the steps of: obtaining an initial value of an antenna design parameter; splitting a tape carrier antenna model region and constructing a calculation model; calculating an electromagnetic initial simulation result of the tape carrier antenna model; setting a tape carrier antenna optimization objectiveand an optimization range of the design parameter, and initializing optimization algorithm parameters; and optimizing the tape carrier antenna design parameter. According to the method provided by the present invention, by using the high-order moment method region decomposition method, the technical problems that only the metallic tape carrier antenna can be simulated and optimized in the prior art, and the optimization efficiency is low are solved, the functions of simulation and optimization to the metallic or dielectric metal mixed tape carrier antenna are realized, and the optimization efficiency is improved.

The invention provides a sparse-representation-classification-based pavement crack detection and identification method. A sparse representation-based classifier (SRC) is introduced and an effective sub-block high-order moment characteristic is selected, thereby avoiding pretreatment and post treatment of an image, simplifying detection steps, and improving the operation efficiency. The method comprises: carrying out extraction and normalization of training set (subblock) characteristic vectors; dividing a tested image into a plurality of sub blocks and extracting features of the sub blocks, and carrying out classification by using an SRC; and identifying a crack type according to a mapping code of a sub block classification result. Compared with the traditional crack detection and identification method, the provided method has the higher identification precision and higher execution efficiency.

The invention discloses a method for calculating a scattering statistical moment of a two-dimensional random rough surface. The method specifically comprises the following steps: utilizing a Beckmanntheory and a Gaussian moment theorem; through strict theoretical derivation, giving a calculation formula of a second moment of a scattering field, coherent and incoherent scattering intensity and a fourth moment of the scattering field. Therefore, the scattering field high-order moment can be degraded to the low-order moment. The correctness of the scattering field four-order moment function is verified. The laser intensity detection quality can be analyzed through the random rough surface scattering four-order moment function. The method can be widely applied to research of rough surface speckle detection problems in national defense and civil fields.

The invention provides a high-order-moment based generated power estimation method and system. The high-order-moment based generated power estimation method comprises the steps as follows: a plurality of sample groups are generated, one sample group which has the smallest characteristic deviation value f with original time series data is determined, wind speed data is simulated according to a wind speed Weibull probability distribution function corresponding to the determined sample group, and generated power is estimated according to the simulated wind speed data. According to the provided generated power estimation method, the accuracy degree for power estimation of wind power generation or photovoltaic power generation can be increased.

The invention belongs to the technical field of antenna measurement, and discloses a three-dimensional vector directional diagram acquisition method which comprises the following steps: acquiring thepartition geometric model of a measurement probe; the electric field distribution on the sphere surrounded by the near region is calculated by using the high-order moment method based on the partitiongeometric mode; and the three-dimensional vector directional diagram of any point in the far field of the probe is obtained by spherical near-far field transformation based on the electric field distribution. The method capable of reducing the calculation amount under the condition of ensuring the accuracy of the three-dimensional vector directional diagram is provided.

The invention discloses a modulation and recognition device and a method for union high-order statistic and spectral peak features. The modulation and recognition device comprises a signal preprocessing module, a high-order statistic feature extraction module, a spectral peak feature extraction module and a union recognition module. Signals to be recognized and modulated are input into the signal preprocessing module so that filtering, carrier frequency estimating and normalization processing can be carried out to obtain the preprocessing signals, and then the preprocessing signals are input into the high-order statistic feature extraction module and the spectral peak feature extraction module so that the features can be extracted, wherein the features include high-order moment features, high-order accumulation features, constellation cluster point values, feature power spectrum variance features, first-order differential amplitude histogram spectral peak number features and the like. The extracted feature information is input into the union recognition module. A classifier based on the union features carries out mode feature matching on the input signals and outputs recognition results. According to the device and the method, recognition of the SC-FDMA modulation mode is achieved for the first time, the recognition rate of the high-order QAM modulation mode is improved, the judgment threshold of recognition in MFSK classes is expanded, and the device and the method can be applied to the fields of frequency spectrum management, electronic countermeasures and the like.

The invention provides a Gaussian filtering method based on multilayer importance sampling and a filter and belongs to the non-linear filtering technology field. The method comprises the following steps of step1, according to actual engineering application, establishing a state equation and a measurement equation of a non-linear system; step2, determining an original state of a system, wherein the original state of the system means a random distribution characteristic of the original state and includes a mean value, a covariance, a high order moment, a noise distribution characteristic and an initial measurement value; step3, according to a calculating complexity, filtering precision and a stability requirement, initializing a sample layer number and a sample type number and calculating a weight of each layer of sample points and a moment matching parameter; and then carrying out one step state prediction and one step measurement prediction, finally, carrying out state filtering updating, using Kaman gain fusion state prediction and measurement data to calculate a distribution characteristic of an optimal state so as to complete an one step estimation task of the non-linear system, and carrying out iteration and returning to a step4 so as to carry out an estimation task of a next moment. The method and the filter possess good performance and practicality.

The invention discloses a reliability evaluation method for a gear pair of a high-pressure internal gear pump. The method comprises the following steps: firstly, defining multiple failure forms of a high-pressure internal gear pump gear pair, and establishing a reliability performance function of each failure form; secondly, calculating the failure probability of each failure form by adopting a saddle point approximation method based on a high-order moment; secondly, constructing an importance measurement model of each failure form of the gear pair of the high-pressure internal gear pump; andfinally, establishing a multi-objective multi-constraint reliability optimization model of multiple performance indexes of the gear pair of the high-pressure internal gear pump. According to the method, the influence of various failure modes of the gear pair of the high-pressure internal gear pump on the reliability of the system is considered, and a plurality of performance indexes required to besimultaneously met by the high-pressure internal gear pump are also considered, so that the working performance of the high-pressure internal gear pump is improved while the gear pair obtained by themethod meets the reliability requirement.

The invention relates to a brain wave analysis method and system. The method comprises the steps of obtaining an original brain wave sequence; determining scales according to preset scale interval and scale step length of the original brain wave sequence; calculating coarse-grained high-order moment brain wave sequences at various scales according to the scales, the original brain wave sequence and a preset high-order moment order, wherein the preset high-order moment order is greater than 2; calculating a high-order moment brain wave information entropies at various scales according to the coarse-grained high-order moment brain wave sequences under various scales and a high-order moment information entropy algorithm and obtaining a multi-scale high-order moment information entropy set of the original brain wave; and determining dynamic change information of the original brain wave sequence according to the multi-scale high-order moment information entropy set. According to the brain wave analysis method and device, the problem of overlarge volatility loss in the sequence coarse graining process caused by a mean value calculation method in a traditional brain wave analysis method is solved.

The invention relates to a weak-signal target detection optimizing method specifically comprising the following steps: (1) reading a discretized input signal; (2) carrying out quadruple autocorrelation on a signal x(n); (3) calculating the frequency spectrum of a correlation function; (4) calculating the frequency spectrum of the signal x(n) according to the relationship between the frequency spectrum of the signal and the frequency spectrum of the autocorrelation function and based on the frequency spectrum of the quadruple-correlated signal; (5) calculating the transfer function of a matching filter; (6) calculating the frequency spectrum of the signal after the signal passes through the filter; (7) using multiple sinusoidal windows to estimate the frequency spectrum; and (8) reducing the frequency spectrum of the signal into a time-domain signal. According to the invention, quadruple correlation and three-spectrum analysis are used to realize signal processing in a high-order moment range, the matching filter is used to calculate the frequency spectrum of the signal after the signal is filtered by the matching filter, and the filter can give the maximum signal-to-noise ratio. By adopting multiple sinusoidal windows to estimate the frequency spectrum, a certain spectrum diagram smoothing effect is achieved, and certain frequency resolution is guaranteed.

The disclosure provides an electromagnetic (EM) sensor system and method that permits rapid and non-invasive measurement of material properties using measurements of the dispersion of EM energy signals over a wide band of frequencies, including second and higher order moments. The EM energy can be a pulse signal, including an ultra-wide band (“UWB”) pulse signal. A plurality of signals can be incrementally projected through the material in a grid. The grid can generally include a series of projections through the material of an object at different angles. The further analysis of the dispersion characteristics of the EM energy signal provides a measure of added features that assist in improved characterization of the material properties. In at least one embodiment, the results of processed pulses through the object can be used to form a two-dimensional or three-dimensional image of the material for the particular property being measured.

A method of nonlinear polarimetry for measuring higher order moments of the E field of an optical signal is provided. The method includes imposing a phase delay on a first polarization of a received optical signal with respect to a second polarization of the optical signal to produce an intermediate optical signal having a time varying polarization. A polarization of the intermediate optical signal is suppressed. The intermediate optical signal is detected with a plurality of photodetectors, with at least one photodetector configured to be responsive to a nonlinear optical process. Spectra of the photodetector outputs are calculated to determine higher order moments of the E field, and the moments are transformed to obtain the polarization measurement.

The invention provides a 32APSK carrier wave loop synchronous locking detection method, and aims to provide a detection method which is accurate in judgment and is not influenced by input signal amplitude. The invention is realized through the following technical scheme: a carrier loop locking state detection module takes out demodulation points from the I data storage module and the Q data storage module respectively; a 32APSK outer ring judgment point calculation module and a 32APSK constellation judgment module are sent to the rear end; inner and outer ring judgment thresholds are calculated; after constellation points of the inner ring and the middle ring are thrown away, the constellation points of the outer ring are sent to a normalization signal high-order moment calculation module; a normalized high-order moment of the outer ring point is calculated; the threshold adjustment module completes the judgment threshold of the outer ring; and the carrier synchronous locking detection loop sends the judgment threshold value of the threshold value adjustment module and the normalized high-order moment calculation value of the high-order moment calculation module to the comparator at each moment, compares the judgment threshold value with a preset locking threshold value, judges the locking state of the 32APSK carrier loop and outputs a carrier locking indication state.

The invention discloses a high-order cumulant-based random harmonic power flow calculation method. The high-order cumulant-based random harmonic power flow calculation method comprises the steps of acquiring a harmonic current sample of a harmonic source having same time sequence in a power grid; performing correlation decoupling on the harmonic current sample to obtain a harmonic current, whereineach harmonic current is independent; calculating high-order moment and high-order cumulant of a harmonic current, and determining a reference running point of a power grid according to the higher moment and the high-order cumulant of the harmonic current; performing linear correction on a preset harmonic power flow model at the reference running point, and calculating the higher moment and the high-order cumulant of the harmonic voltage of the power grid according to the harmonic power flow model after linear correction; and calculating probability density of the harmonic voltage according to the higher moment and the high-order cumulant of the harmonic voltage. By the method, the condition of relatively small harmonic monitoring sample and harmonic randomness and correlation can be adapted, the calculation quantity of random harmonic power flow is effectively reduced, and the probability density analysis accuracy of the power grid harmonic is improved.

The invention provides a 16QAM (Quadrature Amplitude Modulation) carrier demodulation loop locking state synchronous detection method. The 16QAM carrier demodulation loop locking state synchronous detection method can be used for remarkably improving the accuracy of 16QAM carrier locking indication. According to the technical scheme, a locking state detection module takes a segment of data from a16QAM signal subjected to bit synchronization and carrier synchronization and sends the data to an I data storage module and a Q data storage module respectively, and then the data is sent to an adaptive threshold adjustment module and a normalized signal high-order moment calculation module respectively; the self-adaptive threshold adjustment module counts the data distribution number of each constellation point and performs threshold adjustment in a self-adaptive manner according to the distribution condition; and the normalization signal high-order moment calculation module calculates normalization high-order moments of the I and Q signals output by the I and Q data storage modules, sends an output metric value to the comparator, compares the output metric value with a threshold value which is adaptively adjusted, judges the locking state of the 16QAM carrier wave loop, and outputs a carrier wave locking indication state.

The present invention provides a pavement crack detection and identification method based on sparse representation classification. By introducing a sparse representation classifier (Sparse Representation-based Classifier, namely SRC), effective sub-block high-order moment features are selected to avoid image Pre-processing and post-processing are carried out to simplify the detection steps and improve the operating efficiency. Specifically, it includes: extraction and normalization of the feature vector of the training set (sub-block), extracting features from the test image into blocks and using SRC for classification, and identifying crack types according to the mapping code of the sub-block classification results. Compared with the traditional crack detection and recognition method, the method proposed by the invention has higher recognition accuracy and execution efficiency.

The invention discloses a multilayer linear-extension unscented Kalman filter method using higher-order moment matching, belonging to the technical field of nonlinear filtering. The method comprises the following steps: 1, establishing a state equation and a measurement equation of a nonlinear system; 2, determining an initial state value of the system; 3, based on the state estimation and the state equation of the last step, calculating distribution characteristics of random variables of one-step state prediction by using linear-extension unscented transformation; 4, calculating distribution characteristics of random variables after being transformed by the measurement equation, of state prediction by using the linear extension unscented transformation; 5, calculating distribution characteristics of an optimal state by using a Kalman gain in combination with state prediction and actual measurement data; and 6, judging whether the iteration is ended. According to the linear extension method, orthogonally-symmetric samples and a multi-sampling structure are combined by using a proportion modifying idea, and by matching more high-order moments, the approximation accuracy is remarkably improved, the computation complexity is reduced, and the computation efficiency is greatly increased.

The invention discloses a temperature measurement method based on the magnetization of magnetic nanometers. The main innovation of the method is that the influence of the particle size distribution of magnetic nanometer reagents on temperature measurement is considered, and the precise temperature measurement under the condition of unknown magnetic nanometer particle size distribution is realized. When a DC magnetic field is applied to the magnetic nano reagent, the magnetization signal under the excitation of different magnetic field strengths is detected; the temperature is accurately calculated by using the relationship between the magnetization of the magnetic nanoparticle and the temperature, concentration, and high-order moment of the particle size. When an AC magnetic field is applied to the magnetic nano reagent, the AC magnetization signal is collected, and the first and third harmonic amplitudes are detected; the relationship between the first and third harmonic amplitudes of the AC magnetization and temperature, concentration, and high-order moment of particle size is used Accurately solve for temperature. The invention optimizes and improves the temperature measurement method based on the magnetization intensity of magnetic nanometers based on a single particle size. From the experimental data, the temperature error of the optimized method for magnetic nanometer temperature measurement is less than 0.2K.

An improved method and apparatus for the measurement of the polarization of light uses nonlinear polarimetry. The higher order moments of the E field are measured and then transformed into standard polarimetry parameters yielding the polarization of the light. In a first embodiment, the light to be measured is transmitted through a rotating retarder. The retarder is optically coupled to a fixed analyzer and light is then detected by linear and nonlinear photodetectors. The spectra from the detectors is calculated and transformed, to obtain the polarization. In a second embodiment, the light to be measured is received by an optical fiber comprising a plurality of fiber birefringences to retard the light. Polarization sensitive gratings along the length of the fiber scatter the light, and photodetectors detect the scattered light. Apparatus in two preferred embodiments can perform the inventive method.