190results about How to "Reduce computing scale" patented technology

The invention discloses a bearing fault diagnosis method based on improved EMD decomposition and sensitive characteristic selection. The method comprises steps of: performing wavelet noise reduction and EMD decomposition on the original vibration signals of a bearing in different fault states to obtain a plurality of IMF components; selecting, by quantitatively computing the correlation of each IMF component and the corresponding original vibration signal, the first h IMF components including the main fault information of the bearing as an object from which fault characteristic information is extracted, and extracting the characteristic parameters from the IMF components to form a original characteristic set; determining the sensitivity factor of each characteristic in the original characteristic set according to a distance evaluation method and constructing a sensitive characteristic set; inputting the sensitive characteristic vector of a training sample in the fault sample of the bearing into a SVM to be trained, optimizing the kernel function parameter g and the penalty factor c of the SVM according to a genetic algorithm, and identifying the fault of a tested sample. The method may reduce the dimensionality of the fault characteristic vector and the computational scale of a classifier, and increasing fault diagnosis accuracy of the antifriction bearing.

The invention provides a calculation method of the bearing capacity of a reinforced wall plate and belongs to the field of strength analysis of aircraft structures. According to the technical scheme, the calculation method is an axial compression loading action based calculation method of the effective width of buckling of a skin. Stiffness reduction is performed through modification of the cross section area and the moment of inertia of a stringer in a finite element model which is formed by plate beam units after the buckling of the skin is produced, stress analysis of a structure is performed by a linear iteration solution method of load loading steps, comparison is performed on the working stress of the stringer in a calculation result and the allowable limiting stress of a stringer and skin combined structure, the allowable limiting stress serves as a damage standard and is solved based on an engineering method, and accordingly the bearing capacity of the structure is obtained. Compared with the traditional full housing model, a calculation method model is a plate beam unit model, the geometric nonlinearity and contact problem solution which is large in time consumption and difficult to converge is replaced by the linear solution, and accordingly the modeling time consumption is small, the calculation speed is high, and the requirements for the professional quality of the computer hardware and analysis staff are low.

The invention discloses a method for solving the equivalent impedance frequency characteristic of an HVDC transmission system converter under various operating conditions and failure conditions, whichcomprises the following steps: according to the fundamental component of voltage between phases of converting buses and the DC component of direct current, and a trigger angle instruction of a DC control system, calculating the actual trigger angle of each converting valve and the delay angle of flow of the converting valve in the converter, and the actual phase-change angle when two phases are converted; then calculating a three-phase voltage switching function and a three-phase current switching function; and by the subharmonic components of the three-phase voltage switching function and the three-phase current switching function, and the equivalent harmonic impedance of an AC network and a DC network, calculating the equivalent harmonic impedances at the AC side and the DC side of theconverter. The method can realize the calculation of the equivalent harmonic impedances at the AC side and the DC side of the converter under various AC operating conditions and failure conditions, reduce the calculation amount and meet the demand on precision in engineering application.

The invention discloses a dynamic phasor modeling method for a current converter of a high-voltage direct-current transmission system, which is applicable to various operating conditions and fault conditions. The method comprises: calculating the actual trigger angle, the actual phase conversion angle and the actual delay flow angle of various converter valves in the current converter according to first dynamic phasor and direct-current zero-order dynamic phasor of the voltage between phases of a converter bus; calculating the three-phase voltage switch function and the three-phase current switch function according to the actual trigger angle, the actual phase conversion angle and the actual delay flow angle of the various converter valves; and establishing a dynamic phasor model according to the three-phase voltage switch function and the three-phase current switch function. The method can realize the establishment of the dynamic phasor model of the current converter under various operating conditions and fault conditions of AC, reduces the calculation amount, has the precision capable of meeting the requirement of engineering application, and can be applied to simulation analysis of dynamic characteristics of an AC system in an AC and DC compound system under various normal operating conditions and fault conditions.

The invention provides a calculation method of the photovoltaic consumption capability of the power distribution network. The method comprises that parameters of the power distribution network, illumination intensity, ambient temperature and wind speed information required by power flow calculation are obtained; at least one random scene is selected in a Gaussian-like sampling method; according to the parameters of the power distribution network, illumination intensity, ambient temperature and wind speed information, the voltage amplitude of each node of the power distribution network in each random scene is calculated in an annual sequential power flow algorithm; and a maximal photovoltaic installation capacity, which satisfies the constraint range of voltage safety, in a set of the voltage amplitudes is determined and serves as the photovoltaic consumption capability of the power distribution network. Thus, on the premise that the accuracy of calculation results is ensured, the calculation scale is reduced, and the calculation efficiency is improved.

The invention provides a power load prediction method based on variational mode decomposition and a gating cycle unit, and belongs to the technical field of power load prediction. The power load prediction method comprises the following steps: S1, acquiring original load data; S2, decomposing the original load data into a modal function by adopting a variational modal decomposition method; S3, performing normalization processing on the modal function, and dividing the modal function into a training set and a test set; S4, performing gating cycle unit network training on the training set, and establishing a prediction model according to a training result; S5, detecting the prediction model by using a loss function until a loss function value is reduced to be less than a threshold value; andS6, substituting the test set into the prediction model and superposing to obtain a power load prediction result, and evaluating the prediction result. The method is accurate in prediction of data with volatility and randomness, can effectively improve the speed of the model, and can well solve the problem of load prediction of a power system.

The invention discloses a reservoir physical property parameter prediction method combined with deep learning, and the method comprises the steps: introducing the nonlinear correlation between an MICquantitative measurement physical property parameter and a logging curve, and selecting the logging curve which is obvious in response to the physical property parameter; introducing CEEMDAN to decompose the physical property parameter data sequence to obtain an IMF component and a residual RES component of an intrinsic mode function, and subjecting the physical property parameter data sequence tostationary processing; introducing SE to evaluate the complexity of each IMF component and RES margin, and recombining component sequences with similar entropy values to obtain a new intrinsic mode component; carrying out normalization processing on the new intrinsic mode component data and then dividing the new intrinsic mode component data into a training set and a test set; introducing an LSTMrecurrent neural network to establish a prediction model for the reconstructed new component, and obtaining a prediction value of each new intrinsic mode component; and carrying out inverse normalization on the prediction value of each new intrinsic mode component, and carrying out superposition reconstruction to obtain a physical parameter prediction result. According to the method, the modelingnumber of redundant information and prediction components is reduced, and the prediction precision and the prediction speed are improved.

The invention provides an equivalent simplification method for an electric power system with wind power access. The equivalent simplification method comprises the following steps of establishing an equivalent simplification model of an actual electric power system, wherein the actual electric power system comprises a generator and a load model, a steam turbine and a speed controller model, a water turbine and a speed controller model, and a wind turbine generator model; and the equivalent simplification model of the actual electric power system consists of the equivalent simplification models of the generator and the load model, the steam turbine and the speed controller model, the water turbine and the speed controller model, and the wind turbine generator model; performing parameter polymerization on the equivalent simplification model of the actual electric power system according to a polymerization formula; calculating the frequency regulation capability of the equivalent simplification model of the actual electric power system according to a formula; and calculating steady-state frequency deviation and frequency initial drop rate of the equivalent simplification model of the actual electric power system. The established equivalent simplification model of the actual electric power system can replace the actual electric power system, so that the complex actual electric power system can be simplified, and an effect of researching the complex system through the simple models can be realized.

The invention relates to a method for acquiring neutron angular flux density in a nuclear fuel assembly. The method comprises the following steps: 1, calculating value of a primary function; 2, calculating integral of the primary function and angle variable; 3, establishing a wavelet unwrapping equation in the assembly; 4, processing assembly boundary conditions; 5, calculating the neutron angular flux density; 6, establishing the wavelet unwrapping equation with allowance; 7, correcting the neutron angular flux density; and 8, judging whether the neutron angular flux density meets the precision demand or not. According to the invention, argument variable of neutron angular flux density is unwrapped by using a one-dimensional primary function to reduce the calculation scale. By means of adopting the assembly boundary unwrapping and the unwrapping within the assembly respectively, the fuel assembly boundary is unwrapped in areas to avoid calculation of redundancy unwrapping coefficient. As the neutron angular flux density and the allowance are respectively processed, two-time equal coupling scales are just calculated, so that the unwrapping order is relatively and simply improved. Under the premise that approximate computational accuracy is realized, the coupling coefficient is prevented from square increase along with precision improvement, and the calculating efficiency is improved.

The invention provides a reactive voltage coordination control method based on comprehensive benefits of a transmission and distribution power grid. The reactive voltage coordination control method comprises enabling a subordinate power grid to upload gate characteristics to a superior control center; enabling the superior control center to establish a superior and subordinate reactive voltage coordinated optimization global model according to the gate characteristics; performing virtual control partitioning on a superior administered power grid, and obtaining a coordinated optimization calculation model of a plurality of virtual control partitions; enabling the superior control center to obtain optimized values of gate coordination variables of the subordinate power grid by calculation according to the coordinated optimization calculation model and send the optimized values to the subordinate power grid; enabling the subordinate power grid to add coordination variable restraint in an automatic voltage control (AVC) algorithm according to the optimized values of the gate coordination variables, and obtaining a virtual control partition optimization strategy based on the comprehensive benefits of the transmission and distribution power grid; and enabling the superior power grid and the subordinate power grid to perform reactive voltage coordination control according to the virtual control partition optimization strategy. The method improves the running state of the whole network, improves system benefits, reduces model calculation scales and complexity, and is good in reliability and high in compatibility.

The invention discloses a power system topology layered recognition method based on the island search technology. The power system topology layered recognition method comprises following steps: A, reading in data, forming a full topology branch table with an identification based on deconstruction splitting and preprocessing; B, sequentially forming an island branch subtable and a node-site corresponding table according to the full topology branch table; C, forming topology descriptions of station sites according the node-site corresponding table; and D, carrying out instation topology recognition and description. The power system topology layered recognition method is small in computing scale and fast in computing speed, the converted figure interface is clear in layout, and the interstation connection relation and the instation connection relation can be distinguished.

The invention provides an optimal configuration method of a series reactor for limiting short-circuit current. In the method, the economic cost for configuring the series reactor is taken as a target function, and comprises the manufacturing cost, installation cost and support equipment cost of the series reactor. The three-phase short-circuit current of a bus and the transient stability margin of a system are solved through respectively using a classic short-circuit current calculation algorithm and a controlling unstable equilibrium point (CUEP) method, and corresponding constraint conditions are set for the short-circuit current, the transient stability margin and the voltage of the bus so as to meet requirements of the system on safe operation. By using the technical scheme of the invention, the problem that the calculated amount is too large to be realized after the transient stability margin is contained in the constraint conditions is effectively solved, and the current limit scheme meeting the system operation requirements is provided, thereby making up the gap of the field in China and simultaneously having relatively high economical efficiency and practical value.

The invention discloses a prediction method based on VMD and DNN and application in short-term load prediction, and belongs to the technical field of power system short-term load prediction. The method comprises the steps of 1, collecting load data; step 2, performing normalization processing on the acquired data; step 3, decomposing the normalized original load sequence by adopting a VMD method;4, performing deep neural network (DNN) training on the K components obtained in the step 3; and 5, introducing the decomposed test sample into the DNN, and carrying out superposition to obtain a final prediction result. The method is accurate in data prediction with volatility and randomness, can effectively reduce the calculation amount of data, shortens the calculation time, is accurate in prediction result, improves the accuracy of load prediction, and is of great significance for economic dispatching and stable operation of a power system.

The invention discloses a DataMatrix QR code rapid identification method and device, and an electronic device, relating to the technical field of image processing. The method includes taking the gravity center coordinate of the target image as the quadrant center, and dividing the target image into more than three area quadrants; in each area quadrant, using different edge detection operators to calculate only the gradient-increasing edge of the image boundary to the quadrant center to obtain the edge image; taking the quadrant center as the center of a polar coordinate system, and performingthe linear detection on the edge image to obtain four extreme points in the associated area at distances dL and dh from the quadrant center; and in the image area with the four extreme points as the boundary vertexes, generating the segmentation threshold based on the weight average gray value to perform the binary of the QR code data of the target image. According to the invention, the QR code identification accuracy and identification speed can be improved.

The invention provides a regional node network generating method and system of a power distribution network. The regional node network generating method of the power distribution network comprises the steps of establishing a CIM (Common Information Model) tree topology structure; eliminating virtual branches in the CIM tree topology structure and combining transformer winding branches belonging to the same double-winding transformer into a single transformer branch so as to obtain an electric tree topology structure; segmenting the electric tree topology structure into multiple mutually independent regions based on switch branches and regarding each mutually independent region as a single node so as to obtain multiple regional nodes; and restoring a connection relationship of the switch branches among the multiple regional nodes so as to obtain a regional node network. As the regional node network is obtained through contraction of the CIM topology and the electric topology and based on the CIM in the whole process, a highly simplified regional node network is obtained; and as internal devices in the obtained regional node network make the same contribution to the reliability of the power distribution network, the calculation scale can be greatly reduced and the calculation efficiency can be increased while the reliability calculation of the power distribution network is not affected.

The invention discloses a method for accelerating analysis and optimization of a physical layout of an integrated circuit, relating to the technical field of integrated circuits. The method comprises the following steps of: executing region division on the physical layout based on calculation nodes according to input data of the physical layout of the integrated circuit, executing isomorphic analysis on the regions in different calculation nodes, determining the analysis sequences of same regions in each calculation node and among the calculation nodes, analyzing and optimizing the regions of the physical layout according to the sequences, and multiplexing the analyzed and optimized results of the isomorphic regions among the calculation nodes during the analysis and optimization. According to the method for accelerating the analysis and optimization of the physical layout of the integrated circuit disclosed by the invention, the physical layout is divided by utilizing a multi-stage region segmentation algorithm, and the divided regions are analyzed by utilizing an isomorphic analysis method to find out the same regions in the divided regions, so that the posterior regions to be analyzed and optimized in the time sequence are not calculated any more, while the calculation results of the prior regions which are totally same as the posterior regions in the time sequence are multiplexed directly, thus the time is saved and the speed is increased.

The invention discloses a harmonic resolution method of an alternating-current / direct-current interconnection system. The method comprises the following steps: calculating the actual triggering angle,the phase transformation angle and the delay conduction angle of each current transformation valve in a current transformer according to the interphase fundamental-frequency voltage of current transformation buses and the direct-current component of direct current and the triggering angle command of a direct-current control system; calculating a three-phase voltage switching function and a three-phase current switching function and transforming the three-phase voltage switching function switching function and the three-phase current switching function into positive-sequence and negative-sequence components; establishing a sequence component model of the current transformer by the positive-sequence and negative-sequence current switching function and the positive-sequence and negative-sequence voltage switching function; and combining the model and an equivalent harmonic network of the alternating-current / direct-current system and carrying out simultaneous resolution on the total system, thereby calculating each subharmonic voltage and current of both sides of alternating current and direct current of the current transformer. The method realizes the harmonic resolution of the alternating-current / direct-current system under a condition that an asymmetric fault occurs in an alternating-current system, lowers the calculation quantity, has higher calculation accuracy and can be applied to the harmonic analysis of the alternating-current / direct-current interconnection system under various normal operation working conditions and faults.

The invention discloses a dynamic response analyzing method of an aggregation type tensegrity structure based on a sliding rope unit of a multi-body system. The method comprises the following steps that firstly, a traditional tensegrity structure system is transformed into the multi-body system; secondly, based on a traditional rope unit of the multi-body system, the sliding rope unit of the multi-body system is built; thirdly, a multi-body dynamical system equivalence model of the aggregation type tensegrity structure is built by using the sliding rope unit in the second step; fourthly, a differential algebra equation set of multi-body dynamics is solved so as to get the dynamic response of the aggregation type tensegrity structure. In the dynamic response analyzing method, a new strategyof statics and dynamics analysis of the aggregation type tensegrity structure is provided. Compared with an existing non-linear finite element method, the multi-body dynamics modeling analysis is adopted, the modeling process is simple and universal, the operation is simple, and the modeling process is more suitable for the objective physical motion properties of the tensegrity structure system.

The invention relates to the technical field of traffic abnormality detection, and particularly relates to a traffic abnormality detection system based on grey LOF, and a detection method thereof. The traffic abnormality detection system based on grey LOF collects an original data traffic package by an information collection module; the data is preprocessed by a data cleaning technology; a high-associated field of each traffic data package is extracted and concluded as a detection data source; by adoption of a grey level theory, the data provided by the information collection module is analyzed and prejudged through a grey distinction module, so as to greatly reduce the data computing scale, reduce the time complexity of an LOF algorithm, and improve the timeliness; the abnormality degree of the data traffic package is computed through an LOF analysis module; and, based on the density, a separation degree between each traffic package and a nearby traffic package is detected and computed. By adoption of the system and method, the specific abnormal state of the traffic is unnecessary to be preset; compared with the conventional method, the method is more flexible.

The invention discloses an automatic regional power grid voltage reactive power control method based on regional strategy optimization. The method includes the following steps of automatic region division, state preprocessing, generation of a strategy set, strategy evaluation, strategy optimization and obtaining of the optimal strategy through calculation of an evaluation function, and thus reactive power control is carried out on regional power grid voltage. According to the method, voltage reactive power optimal control of the whole power grid is decomposed into independent regions to be respectively optimized, after the regions are formed, calculation and strategy optimization are carried out on the various regions respectively, dependency on measurement accuracy of the whole power grid and the state estimation yield of the whole power grid can be reduced, and whole-grid data transmission interfaces cannot be influenced due to poor measurement quality of a part of regions and inaccurate parameters; the number of calculation models is reduced, calculation scales are reduced, and the calculating speed is increased.

The invention discloses a security constrained optimal power flow method based on power flow transfer relation. The method is characterized by establishing active power flow transfer relationship before and after fault based on anticipated fault analysis; describing fault-state branch active power flow into a ground-state branch active power flow function, so that the fault-state branch active power flow constraint is described as ground-state branch active power flow linear inequality constraint; and carrying out grouping on parallel circuits and parallel main transformers, and reducing the scale of monitored branches by utilizing power flow distribution relationship of branches in each group, and carrying out filtering on the fault-state branch active power flow constraint by utilizing the characteristic that short-time flow capacity of a device is obviously larger than long-term flow capacity thereof to minimize the calculation scale of the SCOPF problem as far as possible. The method has a good effect.

The invention provides a local structural dynamical modeling method and a device. The method is adopted for solving the problems of big data volume, low calculation efficiency and difficulty in locally dynamical responding and finely analyzing as required of the present dynamical modeling. The method comprises the following steps: dividing a whole structure into a first structure and a second structure; establishing an interface multipoint restriction equation for the first structure under the first grid and the second structure under the second grid according to the finite element stiffness matrix and mass matrix of the first structure and the finite element stiffness matrix and mass matrix of the second structure; confirming a vibration mode of the first structure and a vibration mode of the second structure according to the equation; and confirming a deformation compatibility matrix between the DOF (Degree of Freedom) modal displacement of the first structure and the DOF modal displacement of the second structure according to a Moore-Penrose pseudo-inverse method, thereby confirming a dynamical equivalent support effect matrix of the second structure and a fine dynamical finite element model of the first structure.

The invention relates to a method for reconstructing a dynamic fluorescence molecular tomography. The method comprises the following steps of: 1) arranging a small animal-induced fluorescence molecular tomography system; 2) adopting the system to collect fluorescence projected image which reflects the metabolic distribution of a fluorescence probe in an imaging target in a full-angle and equal-interval manner at different time points and storing an acquired image as an input matrix u; 3) generating a KL transformational matrix A based on u; 4) calculating data after the input matrix u is transformed through KL; 5) obtaining L' KL components for 3D reconstruction after KL transformation; 6) generating a weight matrix W1 according to an optical field distribution function Phi x and a green function G; 7) performing 3D reconstruction on each KL component by adopting a 3D FMT reconstruction method according to a formula shown in the description; 8) and performing inverse KL transformation to reconstruction results of the KL components to obtain 4D fluorescence fault sequence. The invention can be widely applied to the reconstruction process of the dynamic fluorescence molecular tomography.

The invention discloses a multi-grid Chebyshev parallel spectral element method. The method includes the steps that a, a calculation area is divided into large and regular units; b, main grids and auxiliary grids are defined in the units, and the main grids are Chebyshev collocation points; c, Wave fields in the units are subjected to Chebyshev truncation expansion by the utilization of the main grids, and medium parameters and external forces in the units are subjected to truncation expansion by the utilization of the auxiliary grids; d, wave field, medium parameter and external force truncation expansion formulas are substituted into a wave equation to obtain unit mass matrixes, unit stiffness matrixes and unit external force vectors; e, on the basis of the unit mass matrixes, the unit stiffness matrixes and the unit external force vectors, an elastic wave expansion is solved on the main grids.

The invention provides a dynamic stiffness modeling method for a flexible support gear transmission device, belongs to the field of gear system dynamic modeling, and aims to divide a common single-layer vibration isolation gear system into a transmission system, a box body, a vibration isolator and a basic module. The method comprises the steps of establishing a concentrated mass model of the transmission system, and converting to obtain a dynamic stiffness equation; establishing a box body finite element model, and obtaining box body dynamic stiffness parameters through harmonic response analysis; simplifying the vibration isolator into a Timoshenko beam, and obtaining a dynamic stiffness equation through a wave equation; obtaining dynamic stiffness parameters by a foundation through a test; by assembling the dynamic stiffness equations of the subsystems, obtaining a complete dynamic stiffness model of the gear transmission device, and hybrid modeling of theoretical parameters / test parameters can be achieved. The modeling method can greatly improve the modeling efficiency of gear transmission device analysis and the accuracy of calculation results.

The invention discloses a rapid calculation and design method for a radial sliding bearing with axial pressure difference, the method comprises the calculation of bearing static characteristic parameters and bearing dynamic characteristic parameters, and known conditions comprise bearing shaft diameter parameters, eccentric parameters and lubrication parameters. Under the working condition of axial pressure difference, the influence of the axial pressure distribution of the radial sliding bearing on the static and dynamic characteristic calculation and parameter design of the bearing is considered, and the oil film pressure, the oil film thickness, the static characteristic parameters and the dynamic characteristic parameters of the bearing are sequentially calculated. The static characteristic parameters comprise oil film force, shaft neck friction force, lubricating oil flow, power loss and effective temperature rise; wherein the dynamic characteristic parameters comprise a rigiditycoefficient and a damping coefficient of the bearing. The method is beneficial to solving the problems of low calculation speed, low efficiency and the like of the characteristic parameters of the existing sliding bearing, and provides a complete standard and method for the design of the radial sliding bearing.

The invention relates to a method for electric power system dynamic economic dispatching with correlation of multiple wind power plants being considered. The method comprises the steps of putting forward a method for generating joint distribution of power output among the multiple wind power plants based on a Copula function, constructing a two-stage band compensation power grid dynamic economic dispatching model based on the distribution, introducing a compensation expected value into an objective function, and solving the compensation expected value by using integration so as to enable the compensation expected value to be converted into a numerical model from a stochastic model, that is, enabling two-stage band compensation dynamic economic dispatching to be converted into a numerical model from a stochastic programming model, thereby quantifying impact imposed on a power grid by a stochastic property of the wind power plants, and solving optimal unit output which satisfies the objective function and the minimum impact simultaneously. According to the invention, solving is carried out by adopting the two-stage band compensation dynamic economic dispatching model, and the solving accuracy of the model is improved.

The invention discloses a method for encapsulating vulnerable elements determined in a printed board component under the effect of dynamic load. The invention aims at providing a method capable of reducing omissions, getting rid of experience dependences effectively, considering the vulnerability of the elements at different positions, sequencing the vulnerability of a plurality of elements and determining the vulnerable elements accurately. The method can be realized by the steps as follows: roughly determining a range of the vulnerable elements in the printed board component by thresholds of feature sizes of the elements, checking the times of each element penetrated by a pitch line of the printed board component in a dominant mode in the determined range, and calculating a vulnerability index P of each element by utilizing the data, wherein the element with the maximum P value is a vibration vulnerable element in the printed board component; then, defining the feature size L of the element as one largest value in three outline dimensions of length, width and height, specifying the threshold of the feature size L as 10mm and taking the L as a foundation for determining the rough range of the vulnerable elements, wherein the L is more than or equal to 10mm; and finally, calculating the P value based on the times of the elements penetrated by the pitch line in the dominant mode.

The invention provides a method and a device for foreground object detection. The device comprises a foreground area detection module, a foreground contour module, a gradient calculation module, and a foreground detection control module. The invention relates to the object identification field and particularly relates to the identification of the foreground object which moves irregularly. The method for the foreground object detection is performed according to the gradient change in the foreground contour masking area. In the prior art, the object moving in a single background Gaussian model is easy to identify as a background, and the object which has stopped for a while and then begins to move is usually identified as another object. The method disclosed by the invention improves the identification efficiency of the foreground object and the identification consistency.