102 results about "Eigenvalue analysis" patented technology

The invention discloses a fat gas mud shale stratum well log standardizing method which comprises the following steps: (a), selecting and constructing a standard layer; (b) carrying out eigenvalue analysis; (c) carrying out curve correction; (d) carrying out standardization effect verification. By utilizing the method disclosed by the invention, when mud shales and neighborhood layers are short of two stable standard layers, curve standardization can be realized, the comparability of well logs of multiple wells is increased, effective popularization of heterogeneous modeling is ensured, and further the precision of heterogeneous logging evaluation is improved.

Aspects of a method and system for an optional closed loop mechanism with adaptive modulations for a multiple input multiple output (MIMO) WLAN system are provided. One aspect of the system may utilize properties of Eigenvalue analysis of MIMO systems to reduce the number of bits of binary information required to select a modulation type among a plurality of modulation types for each spatial stream among a plurality of spatial streams. This provides a reduction in the required number of bits when compared to other approaches and accordingly, enable greater flexibility in systems that utilize closed loop feedback mechanisms.

Aspects of a method and system for an optional closed loop mechanism with adaptive modulations for a multiple input multiple output (MIMO) WLAN system are provided. One aspect of the system may utilize properties of Eigenvalue analysis of MIMO systems to reduce the number of bits of binary information required to select a modulation type among a plurality of modulation types for each spatial stream among a plurality of spatial streams. This provides a reduction in the required number of bits when compared to other approaches and accordingly, enable greater flexibility in systems that utilize closed loop feedback mechanisms.

The invention provides a feature value analysis system for small-interference stability of a large-scale power system, and belongs to the technical field of power system simulation and analysis. The feature value analysis system comprises a BPA data interface module for achieving seamless read-write operation of a BPA data file, a sparse matrix calculation module for achieving relevant sparse matrix processing in small-interference stability feature value analysis, a power flow calculation module, a system modeling and linearization module, a state matrix calculation module, an all feature value calculation engine module, a partial feature value calculation engine module and an oscillation mode extraction and analysis module. Omni-bearing and missing-free feature value simulation analysis for small-interference stability of an actual large-scale power grid is achieved by the adoption of TTQRE and IRAM and JDM with multiple calculation schemes.

The invention discloses a target detection method for a polarimetric interferometry synthetic aperture radar on the basis of eigenvalue analysis, relating to a target detection method for a polarimetric interferometry synthetic aperture radar so as to solve the problem that a ground object can not be detected and identified through the traditional complete polarization and the single polarization synthetic aperture radars under the background of the stronger natural ground object clutter. The target detection method comprises the following steps of: reading in the data of a polarimetric interferometry synthetic aperture radar image according to an image data format; preprocessing the polarimetric interferometry synthetic aperture radar image; obtaining a simplified polarimetric interferometry matrix by two groups of polarized scattering vectors, and solving the characteristic value of a matrix; simplifying the matrix by similar diagonalization and a Jordan standard form to obtain an optimized scattering vector-based correlation coefficient; analyzing an eigenvalue and the statics characteristic of the correlation coefficient by selecting different samples; and constructing a target detector by the obtained statics characteristic to detect an interested target to obtain a result. The target detection method is used for the target detection for the polarimetric interferometry synthetic aperture radar.

A Reasoning Graph is defined as a directed graph characterized by nodes that can be, but are not limited to, concepts, situations, conditions, events, and persons with edges between nodes if one node is a cause of another node (its effect). The Reasoning Graph is automatically generated by analyzing a large corpus text from a repository such as the Wide World Web and other sources. The analysis leads to creation of edges within the graph based on, for example, lexical and semantic analysis of the text. Nodes of the Reasoning Graph can be ranked according to eigenvalue analysis of the connectivity matrix associated with the Reasoning Graph, including through application of both random as well as reasoning surfer models.

The invention discloses an intelligent identification method for the operation condition of a sucker rod type oil pumping unit. The intelligent identification method comprises the steps that firstly, on-well indicator diagrams are collected and converted into underground indicator diagrams; qualitative analysis and quantitative calculation are conducted on the underground indicator diagrams, so that the feature values of the indicator diagrams of various working conditions are obtained; finally, the working state of the sucker rod type oil pumping unit is analyzed through the feature values of the indicator diagrams of various working conditions. By the adoption of the intelligent identification method for the operation condition of the sucker rod type oil pumping unit, the operation state of a current system can be accurately and rapidly judged when the operation condition of the sucker rod type oil pumping unit is identified in real time, the actual operation condition is provided, implementation is easy, operation is stable, the purpose that the working condition of the sucker rod type oil pumping unit is automatically identified, and the operation state of the system is adjusted in real time can be achieved easily , the overall efficiency is improved, and manpower and material resources are saved greatly.

The invention relates to a method for converting a medical record text into structured metadata from a natural language, which comprises the following steps of: 1, extracting characteristic value texts of specific organs, parts and surgical expressions in a text format from a historical case report, and carrying out characteristic value analysis on the characteristic value texts to obtain a characteristic dictionary; 2, exporting historical detection reports needing to be analyzed from a hospital, and merging the historical detection reports into a to-be-processed data set; Step 3, traversingthe patient cases in the data set, segmenting words according to the characteristic value dictionary, and intercepting the description of the organ, the part or the surgical expression; and step 4, persisting the data content intercepted by the part into a structured database. According to the method, historical cases are utilized, a traversal algorithm is used, the use cost is reduced, the generation step of a training set is omitted, lesions of different organs and parts can be conveniently counted, analyzed and searched for through the converted structured cases, and doctors can conveniently carry out medical research, paper writing and teaching.

The invention provides a node admittance matrix eigenvalue analysis method applied to a grid-connected-inverter-included parallel resonance situation, which belongs to the field of inverter-included grid-connected resonance analysis and detection and solves a problem that the resonance generation and the resonance generation frequency can be obtained when the existing resonance detection method analyzes resonance waves, but an optimal observation position and an optimal excitation position in a resonance generation process cannot be determined. When a parallel resonance situation is analyzed in a grid-connected-inverter-included system, the system is subjected to equivalence, a branch of a three-bus system for analyzing the resonance situation of a traditional electric power system is changed into an inverter to perform analysis, thereby obtaining a node admittance matrix of the system, wherein a matrix eigenvalue and left and right eigenvectors are calculated; by analyzing the eigenvalue under every frequency, the eigenvalue under a certain frequency occurs a maximum value, so that the resonance occurs under the frequency; by analyzing left and right eigenmatrixes, the optimal observation position and an optimal excitation position are obtained. The node admittance matrix eigenvalue analysis method provided by the invention is applied to a grid-connected-inverter-included power distribution system.

The invention discloses an island type microgrid small interference stability analysis method, comprising: first, employing a master-slave control strategy for a microgrid system, wherein a main power supply employs droop control, and other power supplies employ PQ control, and an interface inverter control model substitutes for each power supply model in the microgrid system; second, dividing the microgrid system into inverter, network and load modules, respectively establishing a small interference dynamic model for each module, and merging to obtain a complete microgrid system small interference stable model; and finally employing a characteristic value analysis method to analyze microgrid system small interference stability. The method employs a special master-slave control method to analyze microgrid system small interference stability, find microgrid system key links, and provide theoretical basis for microgrid system control parameter optimal configuration.

The invention discloses a vehicle classification method for double-row vertical radar waves. A microwave vehicle detector is installed on the side of the road. The microwave vehicle detector adopts an array type double microwave radar. The microwave vehicle detector is composed of a vector decomposition module and a frequency analysis module. and a microprocessor. The method of the present invention is a comprehensive identification and analysis of the echo characteristics, analyzing the characteristic value of the echo to obtain a group of typing results, analyzing the frequency of the echo, and then obtaining a group of typing results; finally, the The two classification results are weighted to obtain the final vehicle classification result. Because this product adopts the two-level small network classification method in the neural network, it can greatly improve the classification speed, solve the real-time problem of vehicle classification, and improve the accuracy and stability of classification.

The invention relates to a nuclear power unit excitation and PSS parameter optimization setting method enhancing system damping. The method integrates digital-analog hybrid simulation and an on-site test method. Firstly, by means of digital-analog hybrid simulation, frequency domain eigenvalue analysis and time domain disturbance simulation are carried out on a simulation grid, dynamic invariant features and important oscillation information between interconnected network areas are extracted, weight sequencing is carried out on the unit by means of a participation matrix and PF module value, and unit excitation and PSS parameter optimization research is carried out on the nuclear power unit with the largest participation factor; by means of sensitivity analysis, main optimization parameters of an engine excitation system are determined, an optimization interval suitable for AVR and PSS parameters is determined by carrying out simulation research in multiple operation modes, and finally, by means of on-site test research, stability and effectiveness are determined when unit optimization parameters are operated in a power plant are determined. The method can be more suitable for actual grid operation features and can be more suitable for on-site actual units, and guarantees stable operation of a system.

The invention relates to a generalized subspace tracing-based time-varying structure mode parameter identification method. The method comprises the following steps of: firstly measuring a vibration response of a structure with a time-varying characteristic, constructing a multi-dimensional time delay vector according to vibration response monitoring data, calculating a related function matrix of the vector, and initializing a generalized subspace tracing algorithm by adoption of feature value decomposition; secondly, carrying out online updating on the related function matrix of the multi-dimensional time delay vector according to new vibration response monitoring data through importing a forgetting factor, and carrying out online updating on an orthogonal matrix pion (k) by adoption of the generalized subspace tracing algorithm; and finally, calculating a discrete state space matrix and an observation matrix at any moment according to the updated orthogonal matrix pion (k), carrying out feature value analysis on the discrete state space matrix, and extracting mode parameters such as a mode frequency, a damping ratio and a vibration mode of the structure. The method is suitable foridentifying mode parameters of time-varying structures in a plurality of fields, and is simple and convenient to use, high in calculation precision, strong in robustness and high in calculation efficiency.

The invention provides a wind power random fluctuation based generalized load modeling method which comprises the steps of: (1) determining a generalized load model structure, wherein the generalized load model structure comprises a reactive compensation device, a static load, an induction motor load, an asynchronous generator, a power injection module and equivalent impedance of a power distribution network; (2) obtaining aggregation parameters of the asynchronous generator with a statistical synthesis method, and obtaining electric parameters of an equivalent asynchronous generator by performing capacity weighting aggregation on each asynchronous generator; (3) identifying parameters of a load model; (4) configuring a user-defined program and generating a dynamic link library; and (5) injecting power fluctuation data, and during transient analysis and small disturbance characteristic value analysis, shielding the power injection module and only considering dynamic characteristics of the asynchronous generator. When wind power random fluctuation based characteristics are subjected to medium and long-term dynamic analysis, the power injection module is activated for injecting power to a system in a time-varying current form.

The invention relates to a method for detecting characteristics of edge and angular point of color pictures. The technical proposal of the method is characterized by comprising the steps that: calculating the spatial gradient of each color channel of the color pictures, projecting the spatial gradient onto the color space which is insensitive to the illuminance information of shadow, light and shade and spectrum; generating an unchanged-illuminance color tensor by using unchanged-illuminance differential coefficient and own Cartesian inner product; and carrying out characteristic decomposition to obtain the partial orientation corresponding to the maximum characteristic value; then a filtering kernel of a symmetrical orientation tensor is controlled and generated by the partial orientation information, convolution filtering based on the filtering kernel of the symmetrical orientation tensor of the unchanged-illuminance color tensor is carries out to obtain a new color tensor; the characteristic value decomposition of the new color tensor is carried out to obtain a characteristic value and a characteristic vector and derive a characteristic measurement; detecting the characteristic of the edge and angular point. The detection of the characteristic of the edge and angular point is carried out by utilizing the characteristic of the sensor, thereby providing the designed characteristic detecting apparatus with visual characteristic better conforming to the eyes of human beings and restraining stronger noises.

The invention discloses a finite element analysis method of a curved stiffened plate in a high-temperature environment. The method comprises that following steps of: obtaining a plate stiffness matrixthrough considering the influence of temperature change on materials and combining a DST-BK plate element theory; obtaining a rib element stiffness matrix and a rib element mass matrix after rib plate displacement coordination at interfacial surfaces of rib plates according to rib plate displacement coupling conditions; applying a uniform temperature field which is equivalent to thermal load to the plates and carrying out static analysis to obtain a plate additional thermal stress stiffness matrix considering thermal stress and derive a rib additional thermal stress stiffness matrix; carryingout eigenvalue analysis on a global structure stiffness matrix and a global additional thermal stiffness matrix to obtain a buckling critical temperature; superimposing the global structure stiffnessmatrix and the additional thermal stress stiffness matrix to obtain a curved stiffened plate stiffness matrix considering the influence of the temperature on material properties and the influence ofadditional thermal stress; and carrying out eigenvalue analysis on a global mass matrix to obtain the dynamic characteristics of curved stiffened plates in a uniform-temperature environment.

The invention discloses a simplified analysis method for an inherent frequency and the stability of a rotational symmetric structure. The method comprises the steps of establishing a complete dynamic differential equation of a system, a dynamic differential equation adopting a no-extension hypothesis, and a dynamic differential equation adopting an extension hypothesis: establishing the complete dynamic differential equation of the system; establishing the dynamic differential equation adopting the no-extension hypothesis; establishing the dynamic differential equation adopting the extension hypothesis; introducing coordinate conversion for converting the three dynamic differential equations to a support follow-up coordinate system so as to obtain corresponding three constant coefficient partial differential dynamic equations; performing discrete processing on the three constant coefficient partial differential dynamic equations in the support follow-up coordinate system to obtain three constant differential matrix equations; obtaining an eigenvalue of the complete dynamic differential equation and eigenvalues of two simplified dynamic differential equations; and analyzing a parametrically excited vibration mode characteristic and a dynamic stability change law of the rotational symmetric structure according to the three eigenvalues. According to the method, a specific analysis expression of system eigenvalues can be obtained more clearly.

A method and an apparatus estimate an object part location in a digital image using feature value analysis. The method according to one embodiment accesses digital image data representing a region including an object part of a digital image; accesses reference data including class data of classes relating to predetermined positions of the object part in predetermined regions, and features that discriminate among the classes; calculates feature values for the features in the region using pixel values within the region; and determines a location estimate of the object part using the feature values and the reference data.

The invention discloses a wind speed uncertainty counted double-fed wind power additional damping controller 'domain' design method. The method includes steps: S1, establishing a state-space equationof a double-fed wind power delivery system; S2, selecting critical damping alpha cri, and taking a wind speed formed 'wind speed stability domain' as a target to optimize each parameter of an additional damping controller according to a genetic algorithm; S3, according to each parameter, obtained by optimization in the step S2, of the additional damping controller, subjecting the wind power delivery system to characteristic value analysis, judging whether the adopted additional damping controller enables the 'wind speed stability domain' to be the largest or not, if not, returning to the stepS2, and if yes, finishing. The method guarantees robustness of the controller to the greatest extent and is also applicable to design of other additional damping controllers and high in application value.

The invention discloses characteristic value analysis model and step for the subsynchronous resonance analysis of a multi-machine power system, relating to the field of characteristic value analysis models of the subsynchronous resonance analysis of the power system. The deducing and calculating process of a method comprises the following step of: respectively writing a rotor motion equation of amultimass block model of a shaft system of a steam turbine generator, an electromagnetic transient state equation of a magnetic chain and the voltage of a generator, an electromagnetic transient state equation of a power transmission line, an electromagnetic transient state equation of a series-connected compensation capacitor and a control system equation of an excitation controller and the like. The invention obtains a differential equation set related to a state quantity by linearizing the equations on a stable-state operating point and can solve the characteristic value and the characteristic vector of a state equation coefficient matrix on the basis, obtain much information related to resonance damping characteristics by judging the stability of the subsynchronous resonance of the multi-machine power system and can be used for designing a controller to inhibit the subsynchronous resonance of the multi-machine power system by combining with a control theory.

The invention discloses a self-adaption independent component analysis extraction method of weak signals of microseism. The method comprises the steps that each microseism record is preprocessed, and then eigenvalue analysis is conducted so that the number of independent components can be determined; separation is conducted on observation signals according to the ICA algorithm based on kurtosis, so that an initial estimated value of a source signal is obtained; filtering is conducted on the estimated value of each independent component through an improved self-adaption prediction method, and then a self-adaption prediction filtering result of each independent component is obtained; in the process of calculation, fitting is conducted on one loop iteration error and a weight coefficient through a curve fitting method, and a fitting result is substituted into a primary formula for calculation of a next cycle; finally, weight fusion is conducted on the self-adaption prediction filtering results of all the independent components, and the optimal prediction result is obtained. By the adoption of the self-adaption independent component analysis extraction method of the weak signals of the microseism, acute oscillation of errors is reduced, an algorithm result can be stable as expected, the weak signals in the microseism records can be effectively extracted, and the signal to noise ratio of the weak signals is improved.

The invention discloses an improved ESPRIT double-base MIMO radar angle evaluation method, and the method comprises the steps: inhibiting the impact from space domain color noise through building a time domain cross covariance matrix of received data; secondly obtaining the estimation of the noise subspace through an eigenvalue decomposition method; obtaining an automatically-paired estimated angle of a target angle with the fuzzy characteristics through an ESPRIT method; finally obtaining the real target angle estimation through an eigenvalue analysis method. The method can effectively inhibit the space domain color noise in an MIMO radar, and the estimated angles can be paired automatically without additional pairing calculation. Moreover, the method is simple in algorithm, is high in efficiency, and is suitable for the popularization and application in the actual MIMO radar engineering.

The invention relates to an analysis method for researching the regional interaction influence of a wind-solar-fire bundling delivery system, and the method comprises the following steps: 1) constructing a wind-solar-fire bundling delivery system framework mode on the basis of a thermal power generating unit, a wind power generating unit, a photovoltaic power station and a high-voltage direct-current power transmission system model; 2) constructing a small-interference stability analysis linearization model of a delivery system according to the wind-light-fire bundling delivery system framework; 3) using characteristic value analysis and time domain simulation analysis to study the influence of the characteristic value analysis and the time domain simulation analysis on the system oscillation characteristic by changing the electrical distance between the power supplies of a sending-end system and the sending-out distance of the sending-end system; 4) changing the grid-connected capacity and the capacity ratio of wind, light and fire under a given operation condition, and analyzing the influence of different grid-connected capacities of wind, light and fire on the regional stabilityof the system; 5) changing the proportion of the AC / DC transmission power by changing a control current, and analyzing the oscillation modes of the system under different working conditions, therebyproviding a new idea for large-scale new energy consumption and delivery modes.

An embodiment of the invention discloses a method and a device for fatigue test crack diagnosis of an engine body. A strain foil and an acceleration transducer respectively collect strain signals and vibration signals of the engine body in a fatigue test. A data collection card converts the strain signals and the vibration signals respectively into digital signals and transmits the strain signals and the vibration signals which are converted into the digital signals to an industrial personal machine. The industrial personal machine collects a plurality of discrete signals from the strain signals and the vibration signals which are converted into the digital signals, conducts wavelet analysis on the plurality of collected strain signals, conducts signal singularity monitoring on analysis results, conducts Fourier transform on the plurality of collected discrete vibration signals and conducts characteristic value analysis on conversion results. The industrial personal machine judges whether results of singularity monitoring and characteristic value analysis are abnormal or not and judges that an engine has fatigue cracks on yes judgment. The method and the device can reduce unnecessary manpower and financial resources.

The present invention relates to a full-system model establishing method when a multi-port direct current system an alternating current system are interconnected, especially to an estimation method of the full-system electromechanical oscillation mode after the multi-port direct current system is accessed to the alternating current system. The method comprises the following steps: S1: establishing the transfer function model of the multi-port direct current system and the transfer function model of an alternating current system, and determining the coupling relation between the transfer function model of the multi-port direct current system and the transfer function model of an alternating current system; and S2: assessing the influence of the dynamic interaction effect of the multi-port direct current system and the alternating current system on the system electromechanical oscillation mode according to the coupling relation. The present invention provides a derivation method capable of predicting the electrical power system electromechanical oscillation mode after accessing the multi-port direct current system and a rapid estimation method capable of predicting the electrical power system electromechanical oscillation mode after accessing the multi-port direct current system, so that the model order and the computation complexity in the feature value analysis are reduced, and a simple and effective practical method without losing accuracy is provided for the engineering practice.

The invention discloses a finite element analysis method for a curve stiffened plate. The method comprises the following steps: according to a DST-BK element theory, to obtain a plate element stiffness matrix Kp and a plate element quality matrix Mp; at the interface of a rib and a plate, expressing a rib node displacement by using a plate node displacement according to a rib-plate displacement coupling condition, to obtain a rib element stiffness matrix Ks and a rib element quality matrix Ms after the coordination of the rib-plate displacement; adding the rib element stiffness matrix Ks and the rib element quality matrix Ms to the plate element stiffness matrix Kp and the plate element quality matrix Mp, to obtain a stiffness matrix and a quality matrix of the whole stiffened plate structure, and performing the eigenvalue analysis to obtain dynamic features of the curve stiffened plate. The method is capable of using a plate element node coordinate and a displacement interpolation toobtain the rib element stiffness matrix without the superposed rib-plate element nodes, greatly improving the modeling efficiency of the curve stiffened plate; and performing the modeling analysis onthe curve stiffened plate by using a universal analysis method of thick and thin plates, and avoiding a shearing deadlock problem which can be encountered while a first-order shear deformation theoryis used for analyzing.

The invention discloses a small signal stability analysis method for a power system including an asynchronous wind farm based on a safety domain, and the method comprises the steps: (1), determining asynchronous generator, an asynchronous fan and a control system thereof and network frame topology parameters, setting a scene without the asynchronous wind farm as a scene A, and setting a scene with the asynchronous wind farm as a scene B; (2), carrying out the feature value analysis of the rated operation states of the scenes A and B, and carrying out the screening to obtain an electromechanical oscillation mode in a system; (3), carrying out the disturbing of the active output and reactive compensation capacity of the asynchronous wind farm in the scene B and the active output of the synchronous wind farm, recalculating a feature value, analyzing the change of the damping of the electromechanical oscillation mode, and constructing a parameter space of the small signal stability domain; (4), searching small signal stability critical points in the scenes A and B, and constructing a small signal stability of the scene A and a small signal stability of the scene B; (5), comparing thechanges of the small signal stability domains of a system in the scenes A and B, and analyzing the impact on the small signal stability of the system from the asynchronous wind farm grid connection.

The invention discloses a method for evaluating reactive power reserves of an electric power system from the point of view of steady-state voltage stability, and belongs to the technical field of electric power system dispatching and operating. The method disclosed by the invention aims at carrying out eigenvalue analysis on a flow Jacobian matrix for steady-state voltage stability analysis, an eigenvalue whose ratio with the minimum eigenvalue is small is taken as a key eigenvalue, the comprehensive influence degree of node reactive power reserves for the steady-state voltage stability is reflected by the comprehensive sensitivity of node reactive injection for all of the eigenvalues, a low-voltage safe and stable reactive power reserve is differentiated from a high-voltage safe and stable reactive power reserve, and the sum of static reactive power reserves and the sum of dynamic reactive power reserves of each node which takes the comprehensive sensitivity as a weight are further weighted and accumulated, thereby acting as a low-voltage safe and stable reactive power reserve comprehensive index and a high-voltage safe and stable reactive power reserve comprehensive index. The comprehensive evaluation method provides a technical means for monitoring variations in reactive power reserves of the electric power system and comparing the effective degrees of the reactive power reserves under different operating modes by the dispatching and operating personnel.

The invention relates to a hybrid real-time simulation method for continuous long-time steady operation of a power system, and belongs to the technical field of transient simulation of the power system. The method comprises the following steps of: establishing a hybrid real-time simulation interactive computing system and a resolution analysis model for the power system, dividing the power system into an electromagnetic transient side system and an electromechanical transient side system at a meshing interface, analyzing the characteristic value of a state matrix in the resolution analysis model to obtain a computing system mode, judging the mode, setting a one-order inertia system according to the judgment result, verifying the steady gain in the resolution analysis model, and setting a scale factor according to the verification result so as to realize flat start. According to the method, the hybrid simulation can be steadily performed; the method ensures that the hybrid real-time simulation has no steady error so that the hybrid real-time simulation can be continuously performed for long time, and does not affect the simulation of transient and dynamic processes of the hybrid real-time simulation; and the method can ensure that the hybrid real-time simulation reaches a steady state in 3 seconds after closing a loop, and can perform more than 8 hours of continuous hybrid real-time simulation.

The invention discloses a wing structure stochastic-feature value analysis method based on probability density evolution, and belongs to the field of structure design. Uncertainty factors existing ina large complex structure are fully considered, and a stochastic method is utilized to quantitatively characterize uncertain parameters under a condition that sample information is sufficient. A finite-element equation of structure free-vibration is established, feature value analysis is transformed into a generalized feature value problem through modal coordinates, and feature value sensitivity is derived. A feature value probability density evolution equation is established on the basis thereof, and the feature value sensitivity is introduced into the equation to obtain a feature value probability density evolution equation based on sensitivity analysis. The feature value probability density evolution equation is reduced to a standard form through introducing new variables, and a finite-difference method and a total-variation-difference reduction format are employed to obtain a feature value probability density function by solving. Numerical results show that the feature value probability density function obtained by the method of the invention is in better agreement with a Monte Carlo method, and calculation time can be greatly reduced.