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83 results about "Density matrix" patented technology

A density matrix is a matrix that describes the statistical state of a system in quantum mechanics. The probability for any outcome of any well-defined measurement upon a system can be calculated from the density matrix for that system. The extreme points in the set of density matrices are the pure states, which can also be written as state vectors or wavefunctions. Density matrices that are not pure states are mixed states. Any mixed state can be represented as a convex combination of pure states, and so density matrices are helpful for dealing with statistical ensembles of different possible preparations of a quantum system, or situations where a precise preparation is not known, as in quantum statistical mechanics.

Method for rebuilding circulation calm sound source by overlapping spherical wave

InactiveCN101251412ABreak through the shape requirementsSubsonic/sonic/ultrasonic wave measurementSound sourcesDensity distribution
The invention relates to a method of reconstructing a circular stable sound source to be measured through spherical wave superposition in the signal reconstruction technical field. Through setting the sound source to be measured, a microphone array and a reference source microphone, the invention synchronously records the acquired reference signal and holographic measuring point sound pressure, obtains a reference phase from the reference signal, obtains the relative phase relation of the holographic measuring point source pressure acquired by the microphone array through the phase relation between the reference signal and the holographic measuring point source pressure, and finally obtains the self-spectrum correlated density matrix of the sound source signal to be measured through the spherical wave basis function reconstruction computing. Through the reconstruction of the sound source signal to be measured on the holographic measurement surface acquired by the microphone array, the method can analyze the sound source to be measure with random shape and obtain the three-dimensional spectrum correlated density distribution of the sound source to be measured. Compared with the traditional method of reconstructing the stable sound source to be measured through spherical wave superposition, the method can be applicable to the circular stable sound source to be measured with breakthrough on the requirements of the shape of the sound source to be measured.
Owner:SHANGHAI JIAO TONG UNIV

Grid-based spatial multi-scale fast clustering method

The invention discloses a grid-based spatial multi-scale fast clustering method. The method includes the following steps that: S1, a data scale is selected, the size of grids is determined, gridding is performed on sample data, and the density values of the grids is put into statistics; S2, an initial density threshold is specified, all grids satisfying the threshold condition are reserved, and apreliminary density matrix is obtained; S3, a filter template is specified according to an observation scale, and convolution operation is performed on a global grid space; S4, a connected region is generated through neighborhood search so as to be adopted as a preliminary clustering result, integration operation is performed on the grids, the grid space is mapped onto an original point set, and an original point set clustering result is obtained; S5, the observation scale is adjusted, a transformed new filter is adopted to perform operation in the S3 and S4 on a result matrix again, a clustering result of the next observation scale is obtained; and S6, the data scale is changed, the S1 to S5 are repeated, clustering results under different data scales are obtained. The algorithm of the invention has the advantages of low complexity, high clustering efficiency and high precision, and can meet the requirements of real-time multi-scale clustering and visual analysis of massive point sets.
Owner:WUHAN UNIV

Content based general steganography analysis method of spatial-domain image

InactiveCN106548445ASteganographic detection feature aggregationGood distinguishabilityImage data processing detailsSteganalysisFeature vector
The invention provides a content based general steganography analysis method of a spatial-domain image, belongs to the technical field of information safety, and aims at describing the content complexity of the image reasonably, improving features of steganography detection effectively, and improving the accuracy of spatial-domain steganography analysis substantially on the premise that low operand is ensured. The method comprises the steps that 1) a characteristic vector of image content classification is obtained; 2) a K-means clustering algorithm is used divide a training sample into non-intersected classes; 3) a second-order joint probability density matrix in the corresponding vertical direction is calculated and serves as a characteristic vector of steganography detection; 4) classifier models of different types are obtained; 5) an image to be detected is given, the classification characteristic vector is calculated according to the step 1), the image to-be-detected is attributed to a corresponding class according to Euclidean distances from the image to different clustering centers, and characteristics of steganography detection are extracted according to the step 3); and 6) whether the image includes hidden information is determined. The steganography analysis method is mainly applied to image processing.
Owner:TIANJIN UNIV

Feature extraction method for automatic recognition of identity through electrocardiosignal

The invention discloses a feature extraction method for the automatic recognition of identity through an electrocardiosignal, and the method comprises the steps: (1), enabling a training set electrocardiosignal to be converted into a training set pseudo cardiac beat signal, removing the noise in the training set electrocardiosignal, searching the second-order differential zero point of the training set electrocardiosignal, detecting an R wave of the training set electrocardiosignal, and forming a training set pseudo cardiac beat signal matrix through segmenting; (2), extracting the features of the training set electrocardiosignal through employing the training set pseudo cardiac beat signal matrix: calculating the power spectrum density matrix and autocorrelation matrix of the training set pseudo cardiac beat signal matrix, and carrying out the fusion of training set transform domain features and training set time domain features; (3), converting a to-be-recognized electrocardiosignal into a to-be-recognized pseudo cardiac beat signal; (4), extracting the features of the to-be-recognized electrocardiosignal through the to-be-recognized pseudo cardiac beat signal. The method effectively reduces the signal collection time needed by the identity recognition, improves the recognition accuracy, and reduces the calculation cost.
Owner:烽想(山东)医疗科技有限公司

Dynamic calibration method for high-frequency force balance

The invention discloses a dynamic calibration method for a high-frequency force balance, which comprises the steps of performing whitening on a measurement signal x(t) to acquire a whitened signal z(t); seeking an orthogonal matrix V, enabling the whitened signal z(t) to equal to Vq(t), and thus acquiring a separated signal q(t); performing natural frequency and modal damping ratio recognition on the separated signal in modal coordinates; correcting the separated signal according to recognized parameters; and inversely deducing according to the separated signal to acquire a corrected pneumatic load. According to the invention, separation is performed on a coupling signal, and for independent components acquired by separation, natural frequency and modal damping ratio recognition is performed on the separated signals one by one by adopting a curve fitting method through combining aerodynamic characteristics, so that a dynamic amplification effect of a modal coupling system is corrected and eliminated, a real aerodynamic load spectrum density matrix is acquired finally, the reliability of parameter recognition and corresponding HFFB (High-Frequency Force Balance) dynamic signal calibration can be improved to the maximum extent, and an important basis is laid for subsequent accurate estimation for high-rise building prototype wind-induced responses.
Owner:SOUTH CHINA UNIV OF TECH

Online combined resource allocation and payment method based on bilateral auction

ActiveCN110111189AReduce allocation wait timeReduce complexityCommercePaymentRate of convergence
The invention discloses an online combined resource allocation and payment method based on bilateral auction. The method comprises the steps that each buyer (SP) provides quotation information; each seller (MVNO) provides offer information; an auctioneer (the intermediary) calculates a bidding density function and constructs a joint bidding density matrix, and a bidding density sorting vector is obtained through ascending order or descending order arrangement; whether the resources owned by the seller associated with each element completely meet the resources applied by the buyer or not is sequentially judged, and if yes, the corresponding seller and the buyer are taken as a bidding winning mechanism; then, based on the critical minimum bidding density as a reference, a to-be-charged fee qm of each bid winning seller is determined; a to-be-paid fee pn of each bid winning buyer is determined based on the critical maximum bidding density; and finally the buyers and the sellers corresponding to the pn>=qm are selected for matching to realize resource allocation. The method has the advantages that the distribution waiting time can be remarkably shortened, the sum of benefits of three parties is maximized, the convergence speed is high, the complexity is low, and implementation is easy.
Owner:CHONGQING UNIV

Stability analysis system and method of time-varying power system

ActiveCN104680017ASolve the difficult problem of variable stabilitySolve the problem that the stability is not easy to judgeClimate change adaptationSingle network parallel feeding arrangementsElectric power systemSlope stability analysis
The invention discloses a stability analysis system and method of a time-varying power system. The system comprises a data acqusition module, a wind velocity fitting prediction module, a time-varying system establishment and order reduction module, a stability criterion solving module and a result output module, wherein the data acqusition module is used for acquiring data; the wind velocity fitting prediction module is used for performing fitting prediction on conditional wind velocity trend in short time, sectioning the wind velocity and calculating a conditional characteristic wind velocity probability density matrix of each section according to a fitting model; the time-varying system establishment and order reduction module is used for establishing a continuous markov time-varying power system model considering a wind velocity random characteristic and reducing order of the system; the stability criterion solving module is used for solving whether the system is stable by using a feasibility problem solving method in a linear matrix inequality. Through the stability analysis system and method of the time-varying power system, the problem that the stability of the time-varying power system is difficult to distinguish caused by the wind velocity random characteristic in case of fan connection can be effectively solved.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)

Random data-based power system small disturbance stability analysis online identification method

The invention relates to a random data-based power system small disturbance stability analysis online identification method and belongs to the technical field of power system operation and maintenance. The method includes the following steps that: step 1, the output power spectral density matrix of a power system small interference state space model is established; step 2, singular value decomposition is performed on the output power spectral density matrix; step 3, automatic peak identification is performed; and step 4, system modal parameter identification is performed. According to the random data-based power system small disturbance stability analysis online identification method of the invention, with active power adopted as output, singular value decomposition is performed on power spectral density, an automatic peak selection method is adopted to obtain related modal parameters such as frequency and damping, and therefore, accuracy loss caused by the introduction of MAC criteriaand the least squares method to an FDD method can be avoided, the calculation efficiency of FDD modal parameters is greatly improved, and the problem that single channel signals cannot correctly identify a plurality of oscillation modes can be solved; and wide-area measurement information is utilized to identify modal parameters online, and the influence of dimension disasters can be avoided. Themethod has the advantages of simple calculation, high adaptability, and high practical application value.
Owner:NORTHEAST DIANLI UNIVERSITY +1

Automobile six-degrees-of-freedom wheel center force test and vibration noise contribution rate calculation method

The invention discloses an automobile six-degrees-of-freedom wheel center force test and vibration noise contribution rate calculation method. The method comprises the following steps: establishing a coordinate system; arranging measurement points and installing sensors; arranging excitation points and measuring the coordinates of the excitation points; measuring a frequency response function; solving a frequency response function matrix from the center of a wheel hub to a response point; solving a frequency response function vector from the center of the wheel hub to a target point; carrying out road test; solving an excitation power spectrum density matrix; verifying the identification effectiveness of the excitation power spectrum density matrix; and calculating the energy contribution rate of each degree of freedom to the response of the target point. Compared with the prior art, the method of the invention has the following advantages: (1) as the excitation force and excitation torque of the road to automobiles can be considered simultaneously, error caused due to neglect of excitation torque in the prior art is eliminated; and (2) as the energy contribution rate of the wheel center force at each of the six correlated degrees of freedom to the vibration noise of automobiles can be calculated, error caused by an ordinary coherence coefficient method or a multiple correlation coefficient method is avoided.
Owner:SOUTH CHINA UNIV OF TECH

Steel quality detection method based on interval shadow set and density peak clustering

The invention belongs to the field of steel quality testing, and particularly relates to a steel quality detection method based on an interval shadow set and density peak clustering. The method comprises the steps of acquiring an original steel data set, and calculating a distance matrix of the original steel data set through an Euclidean distance formula; obtaining a local density matrix and a relative distance matrix through a calculation formula in density peak clustering; outputting a decision diagram of a data set in density peak clustering, selecting m clustering centers, and classifyingnon-clustering centers to obtain m class clusters; calculating a membership value of each object in the m class clusters; determining an optimal threshold sequence of m class clusters by minimizing fuzzy entropy difference; and based on the optimal threshold sequence, performing three-way classification on non-central objects in the m class clusters by adopting a classification rule according tomembership values of the non-central objects by adopting an interval shadow set, thereby determining a quality detection result of each object, namely, obtaining a quality detection result of the original steel data set. According to the invention, the quality of steel can be effectively and rapidly detected.
Owner:CHONGQING UNIV OF POSTS & TELECOMM

Method for predicting crude oil density by infrared spectroscopy

A method for predicting crude oil density by infrared spectroscopy comprises the following steps: (1) collecting various crude oil samples, determining the densities of the crude oil samples by a standard method, establishing a crude oil density matrix Y; (2) determining infrared spectra of the collected various crude oil samples at different temperatures, performing first-order or second order differential processing, establishing a three dimensional spectrum matrix X (I*J*K) based on absorbances at characteristic spectrum zones of 650-1810 cm-1 and 2750-3100 cm-1, wherein I is the number of the crude oil samples, J is the wavelength point number of the characteristic spectrum zones, and K is the temperature change value, establishing a correction model with the crude oil density matrix established by the standard method by using a multidimensional partial least squares method; (3) determining the infrared spectra of a crude oil sample to be determined at different temperatures under a same condition as the collected crude oil samples, performing first-order or second order differential processing, establishing a three dimensional spectrum matrix Xun based on absorbances at characteristic spectrum zones of 650-1810 cm-1 and 2750-3100 cm-1, substituting Xun into the correction model established in step (2) to obtain the density of the crude oil sample to be determined. The method is rapid in analysis speed, high in testing accuracy, and good in repeatability.
Owner:CHINA PETROLEUM & CHEM CORP +1

Time-varying electric power system self-adaption control method and device

The invention relates to a time-varying electric power system self-adaption control method and a device. The device comprises a data acquisition module, a sub working condition input module, a control feedback response matrix generation module, a combination controller solution module and a result output module, wherein the data acquisition module is used for acquiring time-varying electric power system network structure parameters, generator frequency in the system and power angles; the sub working condition input module is used for acquiring different sub working condition information of the time-varying electric power system, and state transition probability density matrixes under different sub working conditions; the control feedback response matrix generation module is used for confirming control feedback response matrixes corresponding to different sub working conditions of the system; the combination controller solution module is used for confirming a system combination controller; the result output module is used for outputting the system combination controller. Through the application of the method and the device provided by the invention, the problem that a stuck fault set cannot be reasonably matched with the current working condition of the time-varying electric power system can be solved, and the impact caused on the time-varying electric power system when the controller is switched is avoided.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)

Automatic cell counting method based on dynamic learning for microscope

The invention discloses an automatic cell counting method based on dynamic learning for a microscope, and the method comprises the steps: learning the mapping relation between the pixel-level featuresof cells and a distribution function, and obtaining the distribution result of a new cell image at the pixel level; the method comprises the steps that firstly, manually labeling cells and a background of a to-be-recognized image, each cell is represented by a point, and a labeled area with the point as the center point is obtained; then constructing a density function, acting on the marking areaof each cell, and obtaining a corresponding density matrix by taking the marking point as the center; wherein the size of each element value in the density matrix represents the density distributionof the cells in units of pixels, and summing the elements of the whole matrix to obtain the total number of the cells. By establishing the model and learning the relationship between the feature vector of each pixel point in the original image and the corresponding element value in the density matrix, the mapping from the features to the density can be determined, so that the estimation result ofthe cell quantity can be obtained according to the mapping relationship.
Owner:杭州图谱光电科技有限公司

Data Display System and Method

InactiveUS20080135773A1Minimize geometric distortionIncreasing statistical noiseMaterial analysis by optical meansPhotometry using electric radiation detectorsGamma ray attenuationData display
A method for processing transmission data from neutron and gamma-ray radiation to form an image, the neutron and gamma-ray radiation having traversed through an object and representing a measure of neutron attenuation and gamma-ray attenuation introduced by the object, comprising forming a neutron mass attenuation matrix ‘n’ and gamma-ray mass attenuation matrix ‘g’ from the measure of neutron attenuation and gamma-ray attenuation respectively; calculating a composition matrix R whose elements Rij are defined as a function of elements nij from ‘n’ and the corresponding elements gij from ‘g’, R representing an average composition of material between a source which generated the radiation and a point (i,j); calculating a density matrix X whose elements Xij are defined as a function of the elements nij from ‘n’ and the corresponding elements gij from ‘g’, X representing an approximate amount of material between the radiation source and the point (i,j); calculating a quality matrix Q as a function of the elements nij from the ‘n’ and the elements gij from ‘g’, Q representing a measure of the reliability of the elements of Rij; and forming an image for display; wherein the image contains information from R, X and Q.
Owner:COMMONWEALTH SCI & IND RES ORG

Mileage signboard automatic recognition method for road video routing inspection

The invention discloses a mileage signboard automatic recognition method for road video routing inspection. The method comprises the following steps of obtaining video data, and converting the video data into a frame image; using a rectangular frame to select a mileage signboard for dividing the frame image into a positive sample region and a negative sample region, and performing positive and negative sample correction; extracting gradient histogram feature operators of corrected positive and negative samples, and training classification models from feature vectors; outputting a grayscale image of a probability density matrix; calculating a frame image to be tested to perform global binaryzation on a threshold; performing global binaryzation on the output probability density matrix grayscale image to find the maximum connected domain; cutting the corresponding maximum connected domain region ROI in the frame image to be tested; dividing the mileage signboard, and extracting the character region of the mileage signboard; and using wavelet packet texture features and combining a vector machine classifier for performing mileage signboard character recognition. The mileage signboard automatic recognition method has the advantages that the recognition efficiency is high; the accuracy is high; the influence by geographical factors and environment factors is avoided; and the existing hardware equipment is used, so that the cost is low.
Owner:SOUTHWEST JIAOTONG UNIV

Real-time voltage control method for distributed expandable quantum deep width learning

The invention provides a real-time voltage control method for distributed expandable quantum deep width learning. According to the method, a distributed structure and an expandable quantum depth-widthlearning method are combined for voltage control of a power system. Firstly, the proposed method combines the ideas of deep learning and width learning, introduces a density matrix in quantum mechanics, and proposes an expandable quantum deep-width neural network. Secondly, according to the method, four networks of a depth deterministic strategy gradient method structure are fitted by using an expandable quantum deep width neural network, and an expandable quantum deep width learning method is provided. And finally, the voltage of the power system is controlled in real time through a distributed structure. According to the method, real-time global optimal control of the voltage of the power system can be achieved, on the basis of guaranteeing the control precision, the calculation burdenof a controller is relieved, the calculation process is accelerated, the requirement of the voltage control process for the reliability of the communication technology is lowered, and the privacy of power system information of all regions is kept.
Owner:GUANGXI UNIV

Milling process damping calibration method based on operating modal analysis

The invention discloses a milling process damping calibration method based on operating model analysis, and is used for solving the technical problem of poor practicability of an existing milling process damping calibration method. The technical scheme includes the following steps: first obtaining cutter-machine tool system model parameters; then carrying out a no-flutter-stable milling experiment, and measuring vibration signals in an upper position and a lower position in x and y directions of a milling cutter bar; and determining a power spectrum density matrix of the measured vibration signals at each frequency point, performing singular value decomposition on the matrix, then removing characteristic values corresponding to periodic cutting force, performing inverse Fourier transform on the corresponding larger characteristic values, and extracting an average damping coefficient on peak and valley values of an inverse transformation result. After the average damping coefficient is obtained, first cutting force and tool nose frequency response are utilized to obtain a too nose position vibration amplitude value, then the vibration amplitude value together with the average process damping coefficient is substituted into energy balance relational expressions established in the x and y directions, a milling process damping coefficient is calibrated, and he practicability is good.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

Quantum random number generator and quantum random number generation method

The invention provides a quantum random number generator and a quantum random number generation method. The method comprises the following steps of: converting quantum states sent by a random source into two-dimensional quantum states by a compression device and sending the two-dimensional quantum states to a measurement device; randomly using a group of measurement basics in three preset groups of measurement basics to measure the received two-dimensional quantum states by the measurement device according to a preset measurement probability, so as to obtain a measurement result and send the measurement result to an assessment device; taking the measurement result obtained by using random number measurement basics as an initial random number by the assessment device, estimating an average density matrix of each quantum state sent by the random source according to the received measurement result, and calculating randomness of the initial random number according to the average density matrix; and carrying out privacy amplification according to the calculated randomness of the initial random number, so as to obtain a final random number. By applying the quantum random number generation method, the quantum random number generator for the self-detection of the source is realized under a condition that the source is free of assumption, so as to generate required quantum random numbers.
Owner:TSINGHUA UNIV
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