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36results about How to "Guaranteed numerical stability" patented technology
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Electromagnetic transient simulation method of electric system based on matrix exponential
ActiveCN103646152AGuaranteed numerical stabilityGuaranteed accuracySpecial data processing applicationsTransient stateElectric power system
An electromagnetic transient simulation method of an electric system based on a matrix exponential comprises the steps of establishing an electromagnetic transient simulation model, as shown in the specification, of the system to be studied under a state analysis frame, starting a simulation program after setting simulation step sizes delta t and relevant simulation parameters, forming an augmented state matrix with an excitation source g(t) of the current moment, each derivative information and a state matrix A in each simulation step size, solving the matrix exponential e<delta t A> by a Scaling and Squaring algorithm, performing matrix vector multiplication on an augmented state vector formed with a state variable vector x(t) and a p-dimensional unit vector, taking a result as a state variable of the current moment, obtaining an output vector y(t) through an output equation, writing into an output file, simulating and boosting one step size, and judging a short circuit, an open circuit and switch motion firstly in the next simulation step size. The method can achieve electromagnetic transient modeling simulation of the electric system with a complicated structure, asymmetric height, and the model having the characteristic of rigidity.
Owner:ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD +1
Numerical integration method for electric power system full dynamic simulation
ActiveCN101446991AImprove computing efficiencyOvercome the defect of low computational efficiencyComplex mathematical operationsInformation technology support systemTransient stateAlgebraic equation
The invention discloses a numerical integration method for electric power system full dynamic simulation, combining a fixed-step trapezoidal integration method and a variable-step Gear integration method organically in the full dynamic simulation. In the method, the fixed-step trapezoidal integration method, a differential equation of a dynamic element and an algebraic equation of power network are adopted to carry out iterative solution in a mechanical and electrical transient state process of the electric power system full simulation; in the method, the variable-step Gear integration method, the differential equation of the dynamic element and the algebraic equation of the power network are adopted to carry out simultaneous solution in a medium and long-term dynamic process. The fixed-step method and the variable-step method are switched automatically according to a certain strategy in the simulation. The method integrates the advantages of the two original numerical integration methods, thereby overcoming the defect of low calculational efficiency resulting from too small step in the simulation of mechanical and electrical transient state process of the electric power system of the existing full dynamic simulation program while ensuring numerical calculation stability and calculation accuracy.
Owner:CHINA ELECTRIC POWER RES INST +1
Lithium-ion battery SoC (State-of-Charge) estimation method based on improved and self-adaptive dual unscented-Kalman-filters
ActiveCN110398691AFast executionGuaranteed numerical stabilityElectrical testingNumerical stabilityFloating point
The invention discloses a lithium-ion battery SoC (State-of-Charge) estimation method based on improved and self-adaptive dual unscented-Kalman-filters. The method mainly comprises the following steps: 1) establishing a state filter and a parameter filter of a lithium ion power battery based on an equivalent circuit model; 2) coupling the state filter and the parameter filter of the lithium ion power battery based on the equivalent circuit model, and building dual unscented-Kalman-filters; and 3) inputting operation parameters of a to-be-detected lithium ion power battery into the dual unscented-Kalman-filters, and carrying out parameter correction and stage-of-charge (SoC) estimation on a lithium ion power battery equivalent circuit model. According to the method in the invention, the effectiveness of cholesky decomposition is guaranteed, the problem that iteration is stopped due to the fact that a covariance matrix is indefinite caused by reasons such as an initial value error, noisedisturbance, calculation module floating point error and the like is overcome, and the numerical stability of the filtering process and the robustness of the algorithm are enhanced.
Owner:CHONGQING UNIV
Strong tracking UKF filter method based on sampling point changing
InactiveCN103792562AGuaranteed numerical stabilitySolve the problem of non-local samplingNavigational calculation instrumentsNavigation by speed/acceleration measurementsSigma pointNon local
The invention provides a strong tracking UKF filter method based on sampling point changing. The strong tracking UKF filter method based on the sampling point changing comprises the steps that (1) initial parameter setting is carried out on a system; (2) Sigma points are sampled according to an orthogonal transformation sampling point method, a corresponding prediction equation is determined, and time and measurement are updated; (3) fading factors are calculated; (4) new one-step prediction covariance is calculated by using the fading factors, the Sigma points are recalculated, and auto-covariance and cross covariance after the fading factors are introduced are obtained through nonlinear measurement function propagation; (5) filter updating is carried out to the end. According to the strong tracking UKF filter method based on the sampling point changing, the problem of non-local sampling of the system is solved effectively, the precision of the system is improved, and the system is made to have certain strong tracking capability. The strong tracking UKF filter method based on the sampling point changing can be used for solving the problems of poor robustness and filtering divergence when a model of the system is uncertain, solves the problem of the non-local sampling in the high-dimensional system, and expands the application range of strong tracking filter. In an MEMS / GPS combined navigation system, the positioning and attitude determination performance of the MEMS / GPS combined navigation system can be improved through the method.
Owner:HARBIN ENG UNIV
Prediction method of gas-assisted injection molding gas penetration based on finite volume method
InactiveCN103544341AAvoid shockHigh precisionSpecial data processing applicationsLeading edgeFinite element method
The invention discloses a prediction method of gas-assisted injection molding gas penetration based on a finite volume method. The method includes the following steps that (1) a three-dimensional node control body is constructed by cavity entity grids to serve as a finite volume; (2) forming process parameters are set; (3) material parameters are set; (4) the flow velocity, pressure and the temperature of plastic melt are calculated; (5) the flow leading edge of the plastic melt is updated, and the time step length is determined; (6) whether the filler content of the plastic melt reaches an appointed volume or not is judged; (7) the flow velocity, pressure and the temperature of the plastic melt and the flow velocity, pressure and the temperature of gas are calculated; (8) the flow leading edge of the plastic melt and the penetration leading edge of gas are updated, and time steps are determined; (9) whether a cavity is filled or not is judged. The method is based on the three-dimensional finite volume method, a traditional finite volume method is improved, coupled flowing of the plastic melt and gas is calculated, consideration is given to strong nonlinearity among viscosity, the velocity, pressure and the temperature, and distribution of the gas-assisted injection molding gas penetration leading edge and various physical quantity fields can be accurately predicted.
Owner:SHANGHAI JIAO TONG UNIV
Low-voltage active distribution network congestion management method based on node marginal price
ActiveCN109523303ASolve the congestion management problemIncrease numerical differenceMarket predictionsNumerical stabilityComputer network
A low-voltage active distribution network congestion management method based on node marginal price, Firstly, according to the basic principle of positive semidefinite programming algorithm, The nonlinear constraint in the low voltage active distribution network congestion management model based on intelligent soft switching is transformed into the positive semi-definite constraint by the positivesemi-definite relaxation technique, The original non-convex nonlinear model is transformed into a positive semi-definite programming model, and the symmetric component method is used to reduce the mutual impedance coupling between phases, so that the numerical stability of positive semi-definite relaxation can be improved by increasing the numerical difference of the elements in the positive semi-definite matrix. Then the sensitivity factors of branch active power, branch reactive power, node voltage variation and network loss to node injection power are calculated based on the linearizationapproximation principle. Based on the sensitivity factor, a node marginal pricing model is established. The invention can effectively reduce the difficulty of problem solving and ensure the calculation accuracy while improving the calculation speed. It can effectively solve the congestion management problem of low-voltage active distribution network.
Owner:TIANJIN UNIV
Interconnection line model reduction method based on time-domain trapezoidal method difference
ActiveCN102915385AGuaranteed passivityAvoid conversion errorsSpecial data processing applicationsHat matrixNumerical stability
The invention belongs to the field of integrated circuits, and relates to an interconnection line model reduction method based on time-domain trapezoidal method difference. The method comprises the steps as follows: reading performance data of an interconnection circuit, utilizing an improved node voltage method to build a corresponding time-domain equation; utilizing a trapezoidal method to discretize the time-domain equation of the interconnection circuit and obtain a nonhomogeneous recurrence relation; using a nonhomogeneous Arnoldi algorithm to construct a projection matrix, and then using the projection matrix to perform contragradient transformation on the time-domain equation of the interconnection circuit to obtain a reduction system; and finally, using the trapezoidal method to discretize the reduction system to obtain time-domain output. By virtue of the method, the matching of state variables between the reduction system after the time-domain trapezoidal method difference and the original system is ensured; the time-domain reduction precision is ensured; and the numerical stability during the reduction process and the passivity of the reduction system are ensured. Compared with the original time-domain model reduction method, the computing complexity is greatly reduced; and the method has higher precision in time-domain compared with a frequency-domain reduction method.
Owner:FUDAN UNIV
Interference canceling method based on improved all-pass fractional delay filter
InactiveCN104716927AGuaranteed convergenceGuaranteed numerical stabilityDigital technique networkNumerical stabilityMathematical model
The invention belongs to the technical field of digital filter design and in particular relates to an interference canceling method based on an improved all-pass fractional delay filter. The interference canceling method comprises the specific steps of utilizing a minimum mean square error criterion to construct a mathematic model of the all-pass fractional delay filter, utilizing a particle swarm optimization method based on natural selection to solve the mathematic model of the all-pass fractional delay filter and further construct the all-pass fractional delay filter, obtaining reference signals, utilizing the constructed all-pass fractional delay filter to filter the reference signals and carrying out interference canceling process on the filtered signals and signals received by a radar. The interference canceling method uses a natural-selection particle swarm algorithm, guarantees the solving convergence of the filter, quickens the convergence speed, avoids complex numeric calculation, guarantees the solving numerical stability of the all-pass fractional delay filter and enables design of the variable fractional delay filter to be more flexible.
Owner:XIDIAN UNIV
SRAM yield evaluation method based on improved adaptive importance sampling algorithm
ActiveCN111581909AGuaranteed numerical stabilityRaise the ratioComputer aided designComplex mathematical operationsFailure rateAlgorithm
The invention discloses a memory circuit yield evaluation method based on improved adaptive importance sampling. The method can quickly and accurately evaluate the failure rate of static indexes and dynamic indexes of an SRAM unit. The method comprises the following steps: extracting related process parameters of an MOS transistor in PDK provided by a factory, and sampling N failure points throughhyperspherical sampling; constructing N joint normal distributions by using the N failure points, and establishing a corresponding mixed normal distribution as a distorted sampling function; in eachiteration, generating N sample points according to the previous N joint normal distributions; calculating the unbiased estimation of the failure rate and the weight value of the sample; normalizing the weight value of the sample, performing re-sampling according to the weight value, and updating the position parameter by using the re-sampled value; after a round of iteration is completed, judgingwhether variance correction is carried out or not, if not, updating the covariance matrix by utilizing an EM algorithm, and then starting iteration again until the relative deviation is less than 0.1;and otherwise, ending the algorithm and outputting a final result.
Owner:SOUTHEAST UNIV
Vehicle model verification system and method for guardrail safety performance evaluation
PendingCN111401678AAchieve standardizationGuaranteed accuracyDesign optimisation/simulationResourcesVerification systemAutomotive engineering
The invention discloses a vehicle model verification system and method for guardrail safety performance simulation evaluation. By using finite element method computer simulation as a technical means,the method simplifies an actual vehicle and establishes and verifies a vehicle model in a computer analogue simulation system; therefore, whether the highway guardrail structure reaches a corresponding protection level can be accurately reflected and evaluated. Specifically, a sub-component model, a whole vehicle model and a vehicle model before and after the whole vehicle collision are tested andverified through a sub-component test module, a whole vehicle test module and a whole vehicle collision test module respectively, so that the accuracy, numerical stability and effectiveness of the vehicle model are ensured. The test verification of the vehicle model is beneficial to realizing standardization and normalization of the guardrail safety performance simulation system, is a basic guarantee for scientific research technicians to accurately determine the guardrail safety performance, and is also a basic basis for owners and supervisors to check and accept the guardrail design and usesafety performance.
Owner:BEIJING HUALUAN TRAFFIC TECH
AC-DC power grid decoupled load flow simulation model
ActiveCN105337274AGuaranteed numerical stabilityGuaranteed computing efficiencyElectric power transfer ac networkSpecial data processing applicationsTransverterPower balancing
The invention relates to an AC-DC power grid decoupled load flow simulation model. The AC-DC power grid decoupled load flow simulation model comprises an AC network part Delta Sph, a DC network part Delta Dph, a transverter part Delta Vph and a control equation Delta Vkz, wherein the AC network part Delta Sph comprises an AC node active balance equation Delta Ps and an AC node reactive balance equation Delta Qs; the DC network part Delta Dph comprises a DC node power balance equation Delta Pd; the transverter part Delta Vph comprises a transverter AC side active balance equation Delta Pcs, a transverter AC side reactive balance equation Delta Qcs and a transverter DC side power balance equation Delta Pcd; and the control equation Delta Vkz comprises a constant DC side voltage control equation Delta icuc_set, a constant AC side active control equation Delta PcPs_set, a constant AC side reactive control equation Delta QcQs_set and a constant AC side voltage control equation Delta QcUs_set. The AC-DC power grid decoupled load flow simulation model can guarantee the calculation efficiency for parallel computing for load flow simulation in a large scale AC-DC hybrid power grid for the model.
Owner:STATE GRID FUJIAN ELECTRIC POWER CO LTD +3
Active power distribution network dynamic simulation method based on multistage optimization pursuit variational iteration method
ActiveCN111900718AOptimize solve orderSmall amount of calculationSingle network parallel feeding arrangementsPhotovoltaic energy generationTheoretical computer scienceIterative method
The invention discloses an active power distribution network dynamic simulation method based on a multistage optimization pursuit variational iteration method. The method comprises the steps offirstlycarrying out the improvement of a variational iteration algorithm in two aspects: on one hand, considering a solved approximate analytical solution at the right side of a correction functional,and onthe other hand, preferentially calculating a differential equation with higher coupled frequency such that an optimization pursuit variational iteration method with faster off-line convergence is provided,secondly, solving approximate analytical solutions corresponding to dynamic elements in a photovoltaic system and a synchronous generator system in the active power distribution network based onthe method,and then, introducing a multi-stage mechanism is introduced.An approximate analytical solution is applied to continuous time intervals, and a limited convergence domain of an original variational iteration method is broken through, so that the method can be applied to active power distribution network simulation requiring an accurate solution in a larger time span. Compared with a traditional numerical integration method, the method is higher in solving speed.
Owner:SOUTHEAST UNIV
Method for mixed explicit implicit integration applicable to random dynamic simulation of active power distribution network
ActiveCN106855909AEfficiently handle dynamic simulation problemsCalculation speedGeometric CADSpecial data processing applicationsNumerical stabilityIntegration algorithm
The invention relates to a method for mixed explicit implicit integration applicable to random dynamic simulation of an active power distribution network and belongs to the field of active power distribution network simulation. Random characteristics and multi-time scale characteristics in the process of operating the active power distribution network are considered. The method is based on a mixed explicit implicit solving idea, an explicit integration algorithm is adopted to integrate a random disturbance term forming an active power distribution network random dynamic model, and an implicit integration algorithm is adopted to integrate a deterministic model for forming the active power distribution network random dynamic model. According to the method, numerical solution advantages of the explicit integration algorithm and the implicit integration algorithm can be brought into full play, and the method is applicable to random dynamic simulation calculation of a system under malfunction or operation conditions. Compared with a conventional explicit integration algorithm, simulation calculation efficiency and numerical stability are improved while numerical precision needed for simulation is met, and the random dynamic simulation of the active power distribution network under the conditions of considering integrated access of photovoltaic and wind power generation systems is implemented.
Owner:STATE GRID ECONOMIC TECH RES INST CO +1
Nuclear thermal coupling iteration method of supercritical water reactor core
ActiveCN105468832ATroubleshoot iterative convergence issuesGuaranteed numerical stabilityComputer aided designSpecial data processing applicationsIteration functionRelaxation factor
A nuclear thermal coupling iteration method of supercritical water reactor core comprises: after carrying out m times of neutronics calculation, carrying out one time of thermotechnical hydraulic calculation, wherein m is set neutronics calculation iteration times, m is greater than 5; in the process of carrying out the neutronics calculation, introducing a self-adaption relaxation factor omega and utilizing a power density distribution iteration function to adjust the power density distribution obtained by carrying out the second to the mth neutronics calculation, wherein the adjusted power density distribution is used in the next time of neutronics calculation or thermotechnical hydraulic calculation. The invention solves the problem that iteration calculation in the nuclear thermal coupling iteration calculation of the SCWR core is difficult to converge and improves the calculation efficiency and numerical stability of the nuclear thermal coupling calculation.
Owner:NUCLEAR POWER INSTITUTE OF CHINA
State estimation method based on tensor method
InactiveCN103280803AAvoid calculationAvoid storageAc network circuit arrangementsNumerical stabilityEstimation methods
The invention discloses a state estimation method based on a tensor method. According to the state estimation method, through calculation of a tensor equation, then a nonlinear correction is obtained. Calculation and storage of a Hessian matrix are avoided. The calculating efficiency of nonlinear state estimating is better improved, and meanwhile, robustness and especially numerical stability of the estimation of the nonlinear state are kept.
Owner:HOHAI UNIV
Battery energy storage system scheduling method considering dynamic charge and discharge efficiency
ActiveCN110504701AGuaranteed numerical stabilityEfficient solutionFlexible AC transmissionSingle network parallel feeding arrangementsDischarge efficiencyDynamic planning
The invention relates to a battery energy storage system scheduling method considering dynamic charge and discharge efficiency. The method comprises the following steps: A, acquiring basic informationof a battery energy storage system, and performing segmented linearization on a charge and discharge efficiency characteristic curve; B, acquiring scheduling information such as running limit, initial and final electricity quantities, a predicated time-sharing electricity price or a price multiplier and the like of the battery energy storage system; C, establishing a scheduling model; D, calculating the dynamic upper limit and lower limit of storing the electric quantity by the battery energy storage system in each time period; E, performing dynamic planning on reverse recursion to obtain anoptimization model of a core sub-problem needing to be repeatedly solved in each time period; F, using geometric features of the core sub-problem optimization model to sequentially solve an optimal path in each horizontal sub-region from bottom to top; G, solving the optimal path in the horizontal sub-regions; H, processing the optimal path jump; I, performing dynamic planning on forward recursion, and calculating the optimal charge and discharge electric quantity and power decision of each time period; and J, entering the next time period along with the schedule development, updating the scheduling information in the step B, and executing the step C. According to the method, an effective way is provided for optimized operation of the battery energy storage system, and an engineering practical value is achieved.
Owner:XIAN THERMAL POWER RES INST CO LTD
Video transcoding method and device based on geometric generation model, medium and equipment
ActiveCN113344786AAvoid confrontational learning processEasy to storeImage enhancementImage analysisComputer graphics (images)Image resolution
The invention discloses a video transcoding method and device based on a geometric generation model, a medium and equipment, and the method comprises the steps: constructing the geometric generation model, and obtaining a super-resolution reconstruction model after training; obtaining an MPEG-4 video; decoding the MPEG-4 video, and storing the decoded MPEG-4 video in a continuous static picture form; for each frame of picture obtained after the MPEG-4 video is decoded, performing super-resolution amplification reconstruction on each frame of picture through a super-resolution reconstruction model; and encoding the image after super-resolution amplification and reconstruction into a video in an H.265 format. According to the method, the problem of mode collapse in the generative adversarial network is solved from the perspective of geometry through the geometric generative model, adversarial learning is avoided, and the generated image is richer and more vivid.
Owner:SOUTH CHINA UNIV OF TECH
Model output post-processing method and deviceand computer equipment
ActiveCN113763960AGuaranteed numerical stabilitySmall amount of calculationSpeech recognitionComputer devicePathPing
The invention provides a model output post-processing method and device and computer equipment. A recognition system obtains a probability matrix output by a speech recognition model, carries out window search in the probability matrix, carries out rule processing on the probability matrix based on a threshold value, eliminates invalid paths in the probability matrix, the probability calculation of the next window interval of the probability matrix is calculated based on the probability result of the previous window interval, and the probability value corresponding to each window interval is calculated. Finally, the command word corresponding to the window interval with the highest probability value is selected as a speech recognition result. According to the method and device, the numerical stability of the probability matrix is effectively ensured through threshold-based rule processing. Log domain calculation is replaced by a probability accumulation calculation mode, so that the calculation amount is reduced. In the window searching process, the probability calculation of the latter window interval is based on the probability result of the former window interval, so that the repeated calculation process is reduced, the calculation amount is further reduced, and the processing speed is effectively accelerated.
Owner:深圳市友杰智新科技有限公司
UKF algorithm-based lithium ion power battery state estimation method
ActiveCN110837049AGuaranteed accuracyReduce computational overheadElectrical testingDesign optimisation/simulationSelf adaptiveMeasurement equations
The invention discloses an UKF algorithm-based lithium ion power battery state estimation method. According to the method, on-line estimation and updating are performed on parameters of a time-variable charge state space model and a health state space model by a joint estimation strategy, so that model accuracy under a dynamic test working condition can be effectively ensured, and the lithium ionpower battery state estimation accuracy is improved. Moreover, during unscented transformation, quasi-linear processing is performed on a measurement equation, so that calculation cost during the cycle iterative process is reduced very well; by on-line estimation and correction on statistic characteristic parameter of process noise, and the self-adaptive fault-tolerant capability of the UKF algorithm is greatly improved; and the convergence of filtering is traced in real time, filtering divergence is prevented by correcting covariance when a filtering result is in a divergent trend, and the numerical value stability during the filtering process is ensured.
Owner:WUXI INNOVATION CENT CO LTD
Large-step-size multi-switch electromagnetic transient state simulation method capable of setting time in real time
ActiveCN102779209BHigh speedHigh precisionSpecial data processing applicationsTiming marginAccuracy improvement
The invention relates to a large-step-size multi-switch electromagnetic transient state simulation method capable of setting time in real time. The method includes the following steps: calculating a first step-size point state value of electromagnetic transient state and finding that the switching motion exists in the step size; performing interpolated value calculating for a first switching motion point state value; performing interpolated value calculating for a second switching motion point state value; calculating a next step-size point state value; calculating the whole step-size point state value from the state value interpolated value of the current step-size point; and calculating the whole step-size point state value from the state value extrapolated value of the current step-size point. The method can improve calculating speed of a switching subnet, is favorable for timeliness calculating, provides time margin for improvement of switching calculation accuracy, can be applied to electromagnetic transient state simulation calculating of switching characteristic circuits of real-time calculating, super real-time calculating and off-line calculating, can be compatible with various electromagnetic transient state switching algorithms, effectively improves simulation calculating speed and accuracy, and optimizes electromagnetic transient state real-time calculating performance.
Owner:CHINA ELECTRIC POWER RES INST +1
Numerical integration method for electric power system full dynamic simulation
ActiveCN101446991BImprove computing efficiencyOvercome the defect of low computational efficiencyComplex mathematical operationsInformation technology support systemTransient stateAlgebraic equation
Owner:CHINA ELECTRIC POWER RES INST +1
Simulation model of decoupled power flow for AC and DC power grids
ActiveCN105337274BGuaranteed numerical stabilityGuaranteed computing efficiencyElectric power transfer ac networkSpecial data processing applicationsTransverterPower grid
The invention relates to an AC-DC power grid decoupled load flow simulation model. The AC-DC power grid decoupled load flow simulation model comprises an AC network part Delta Sph, a DC network part Delta Dph, a transverter part Delta Vph and a control equation Delta Vkz, wherein the AC network part Delta Sph comprises an AC node active balance equation Delta Ps and an AC node reactive balance equation Delta Qs; the DC network part Delta Dph comprises a DC node power balance equation Delta Pd; the transverter part Delta Vph comprises a transverter AC side active balance equation Delta Pcs, a transverter AC side reactive balance equation Delta Qcs and a transverter DC side power balance equation Delta Pcd; and the control equation Delta Vkz comprises a constant DC side voltage control equation Delta icuc_set, a constant AC side active control equation Delta PcPs_set, a constant AC side reactive control equation Delta QcQs_set and a constant AC side voltage control equation Delta QcUs_set. The AC-DC power grid decoupled load flow simulation model can guarantee the calculation efficiency for parallel computing for load flow simulation in a large scale AC-DC hybrid power grid for the model.
Owner:STATE GRID FUJIAN ELECTRIC POWER CO LTD +3
Interference Cancellation Method Based on Improved All-pass Fractional Delay Filter
InactiveCN104716927BGuaranteed convergenceGuaranteed numerical stabilityDigital technique networkNumerical stabilityMathematical model
The invention belongs to the technical field of digital filter design, and in particular relates to an interference cancellation method based on an improved all-pass fractional delay filter. The specific steps are: adopting the minimum mean square error criterion to construct an all-pass fractional delay filter Mathematical model; adopt the particle swarm optimization method based on natural selection to solve the mathematical model of described all-pass type fractional delay filter, and then construct all-pass type fractional time-delay filter; Obtain reference signal, utilize the all-pass type that constructs The type fractional delay filter performs filtering processing on the reference signal, and performs interference cancellation processing on the filtered signal and the signal received by the radar. The present invention adopts the particle swarm algorithm of natural selection, which ensures the convergence of the solution of the filter, accelerates the convergence speed, does not require complicated numerical calculations, and ensures the numerical stability of the solution of the all-pass fractional time-delay filter. Variational fractional delay filter design is more flexible.
Owner:XIDIAN UNIV
Cost reducing method for RCS interconnected circuit with multi-output and multi-input
InactiveCN1645379AGuaranteed numerical stabilitySpecial data processing applicationsMulti inputNumerical stability
An order reducing method includes setting up second order system equation to describe the interconnected circuit, carrying out frequency shift and linearization for the secondary system, using second order block Arnoldi algorithm to obtain a set of orthogonal standard base, obtaining order reduced secondary system by orthogonal projection, linearizaing the secondary system to be primary circuit equation with block structure in original secondary equation for obtaining small size RCS equivalent circuit.
Owner:FUDAN UNIV
Prediction method of gas penetration in gas-assisted injection molding based on finite volume method
InactiveCN103544341BAvoid shockHigh precisionSpecial data processing applicationsLeading edgeFinite element method
The invention discloses a prediction method of gas-assisted injection molding gas penetration based on a finite volume method. The method includes the following steps that (1) a three-dimensional node control body is constructed by cavity entity grids to serve as a finite volume; (2) forming process parameters are set; (3) material parameters are set; (4) the flow velocity, pressure and the temperature of plastic melt are calculated; (5) the flow leading edge of the plastic melt is updated, and the time step length is determined; (6) whether the filler content of the plastic melt reaches an appointed volume or not is judged; (7) the flow velocity, pressure and the temperature of the plastic melt and the flow velocity, pressure and the temperature of gas are calculated; (8) the flow leading edge of the plastic melt and the penetration leading edge of gas are updated, and time steps are determined; (9) whether a cavity is filled or not is judged. The method is based on the three-dimensional finite volume method, a traditional finite volume method is improved, coupled flowing of the plastic melt and gas is calculated, consideration is given to strong nonlinearity among viscosity, the velocity, pressure and the temperature, and distribution of the gas-assisted injection molding gas penetration leading edge and various physical quantity fields can be accurately predicted.
Owner:SHANGHAI JIAOTONG UNIV
Post-processing method, device and computer equipment for model output
ActiveCN113763960BGuaranteed numerical stabilitySmall amount of calculationSpeech recognitionNumerical stabilityPathPing
The application provides a post-processing method, device, and computer equipment for model output. The recognition system obtains the probability matrix output by the speech recognition model, performs window search in the probability matrix, and performs regular processing on the probability matrix based on thresholds to eliminate the probability matrix. Invalid paths in the matrix, and the probability calculation of the next window interval of the probability matrix is based on the probability result of the previous window interval, and the corresponding probability values of each window interval are calculated respectively. Finally, the command word corresponding to the window interval with the highest probability value is selected as the speech recognition result. In this application, the numerical stability of the probability matrix is effectively guaranteed through threshold-based rule processing. And the method of probability multiplication calculation is used to replace the log domain calculation, thereby reducing the amount of calculation. In the process of window search, the probability calculation of the next window interval is based on the probability result of the previous window interval, thereby reducing the process of repeated calculation, further reducing the amount of calculation, and effectively speeding up the processing speed.
Owner:深圳市友杰智新科技有限公司
M-UFSPML model, construction method, intelligent terminal and server
PendingCN113435074AEnsure consistencyLess computing and storageDesign optimisation/simulationComplex mathematical operationsNumerical stabilityPerfect matched layer
The invention belongs to the technical field of perfect matching layer construction, and discloses an M-UFSPML model, a construction method, an intelligent terminal and a server, and the method comprises the steps: carrying out the Fourier transform of a weak form of a time domain second-order linear elastic anisotropy wave equation, and obtaining a corresponding frequency domain equation; on the basis of the concept of a multi-axis complete matching layer, adopting a complex coordinate continuation technology to carry out continuation on space variables in a weak form frequency domain wave equation, and obtaining a newly constructed artificial boundary, namely a non-split convolution multi-axis perfect matching layer. The precision of the newly constructed non-split convolution multi-axis perfect matching layer is improved compared with that of a previous multi-axis perfect matching layer, and meanwhile it can be guaranteed that calculation lasts for a long time and is stable. The newly constructed non-split convolution multi-axis perfect matching layer adopts a non-split form, the direct discrete space second-order partial derivative is avoided, the calculation efficiency is higher, the numerical result can ensure the numerical stability of more than 100,000 step lengths, and the precision is obviously superior to that of a low-order artificial boundary.
Owner:INST OF ENG MECHANICS CHINA EARTHQUAKE ADMINISTRATION
Active distribution network dynamic simulation method based on multi -level optimization chase and changing iteration method
ActiveCN111900718BOptimize solve orderSmall amount of calculationSingle network parallel feeding arrangementsPhotovoltaic energy generationTheoretical computer scienceDistribution system
The invention discloses a dynamic simulation method for an active distribution network based on a multi-level optimization and chasing variational iterative method. First, the variational iteration algorithm is improved in two aspects: on the one hand, on the right side of the correction functional, the The approximate analytical solution has been obtained; on the other hand, differential equations with higher coupled frequencies are preferentially calculated. Therefore, an optimization chasing variational iterative method with faster offline convergence is proposed. Secondly, based on this method, the approximate analytical solutions corresponding to the photovoltaic system in the active distribution network and the dynamic elements in the synchronous generator system are obtained. Subsequently, a multi-stage mechanism is introduced, that is, the approximate analytical solution is applied on continuous time intervals, which breaks through the limited convergence region of the original variational iteration method, so that it can be applied to active distribution systems that require accurate solutions in larger time spans. power grid simulation. This method is faster than the traditional numerical integration method.
Owner:SOUTHEAST UNIV
Li-ion power battery SOC estimation method based on improved adaptive double unscented Kalman filter
ActiveCN110398691BFast executionGuaranteed numerical stabilityElectrical testingPower batteryKaiman filter
Owner:CHONGQING UNIV
An Iterative Method for Core-Heat Coupling of Supercritical Water Reactor
ActiveCN105468832BTroubleshoot iterative convergence issuesGuaranteed numerical stabilityComputer aided designSpecial data processing applicationsNumerical stabilityNuclear engineering
Owner:NUCLEAR POWER INSTITUTE OF CHINA
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