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221 results about "Numerical stability" patented technology
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In the mathematical subfield of numerical analysis, numerical stability is a generally desirable property of numerical algorithms. The precise definition of stability depends on the context. One is numerical linear algebra and the other is algorithms for solving ordinary and partial differential equations by discrete approximation.
Statistical delay and noise calculation considering cell and interconnect variations
ActiveUS7890915B2Efficiently delayEfficiently sensitivityAnalogue computers for electric apparatusComputation using non-denominational number representationNumerical stabilityComputer science
The electrical circuit timing method provides accurate nominal delay together with the delay sensitivities with respect to different circuit elements {e.g., cells, interconnects, etc.) and variational parameters (e.g., process variations; environmental variations). All the sensitivity computations are based on closed-form formulas; as a consequence, the method provides rapidly and at low cost high accuracy and high numerical stability.
Owner:SYNOPSYS INC
Method, system and apparatus for simulating fluid flow in a fractured reservoir utilizing a combination of discrete fracture networks and homogenization of small fractures
ActiveUS7565278B2Increase the number ofImprove stabilitySurveyAnalogue computers for chemical processesNumerical stabilityFracture aperture
Owner:CHEVROU USA INC
Self-adjusting voltage filtering technique compensating for dynamic errors of capacitive voltage transformers
ActiveUS20080243413A1Digital technique networkVoltage/current isolationNumerical stabilityTransformer
A method of digitally correcting the raw output voltage from a Capacitive Voltage Transformer (CVT) with the intent to remove transient components impacting on transient accuracy of protection function. A typical CVT is represented using three parameters in the linear CVT model. A digital filter designed based on the three parameters and incorporating a dedicated mechanism to ensure numerical stability of the former. A method of self-adjusting the said filter based on system events and performed after the method has been deployed in the field and supplied from a specific CVT.
Owner:GENERAL ELECTRIC CO
Synchronous vector measuring device
ActiveUS20050151532A1Improve continuityImprove stabilityPower measurement by digital techniqueEmergency protective arrangements for automatic disconnectionNumerical stabilityMeasurement device
A synchronous vector measuring device can measure an absolute phase angle of a synchronous vector excellent in continuous numerical stability at high speed and with high accuracy in a noisy electric power system. A voltage measuring part measures the voltage of the electric power system at a period equal to 1 / 4N (N being a positive integer) of one period of a reference wave. A voltage root-mean-square value calculation part calculates, at each voltage measuring timing, a voltage root-mean-square value at a specific timing from the voltages measured at past 4N timings including the specific timing. An absolute phase angle calculation part makes, at each voltage measuring timing, an inverse cosine of a value obtained by dividing the voltage measured at the specific timing by the product of the voltage root-mean-square value and the square root of 2, as the absolute phase angle of the synchronous vector at the specific timing.
Owner:MITSUBISHI ELECTRIC CORP
CT imaging system and method
ActiveCN103913472AImprove numerical stabilityImage enhancementReconstruction from projectionNumerical stabilityPhoton counting detector
The invention discloses a CT imaging system and a method. The method includes: conducting common CT scanning on an object to obtain a common CT image, then determining an area-of-interest in the image, making use of a photon counting detector to perform CT scanning on the area-of-interest from multiple energy windows, and then re-establishing a high resolution image of the area-of-interest. The photon counting detector is employed to collect the photon counting projection data of multiple energy windows, so that decomposition of multiple basis functions can be carried out, the energy spectrum can have high discrimination, and the numerical stability can be good.
Owner:NUCTECH CO LTD +1
Topological optimization method based on meshfree RKPM (reproducing kernel particle method) for thermal structure of anisotropic material
ActiveCN106845021AImprove reliabilityFlexible handlingDesign optimisation/simulationSpecial data processing applicationsNumerical stabilityStiffness matrix
The invention discloses a topological optimization method based on a meshfree RKPM (reproducing kernel particle method) for a thermal structure of an anisotropic material. The method comprises a step of establishing a meshfree RKPM thermal stiffness matrix of the structure of the anisotropic material with a transformation matrix method, and the step comprises the following sub-steps: (1) solving dynamic influence domain radius of each calculation point according to coordinate information of input nodes and Gaussian points; (2) solving relative density of each RKPM node according to an RAMP (rational approximation of material properties) material interpolation model; (3) searching Gaussian points in a design domain, and establishing thermal conductivity tensor of each node according to the thermal conductivity of the anisotropic material, an orthotropic factor and a material direction angle; (4) taking a dot product of a thermal conductivity coefficient matrix and a geometric matrix of each node as an RKPM thermal stiffness matrix of the node; (5) forming the integral RKPM thermal stiffness matrix in the design domain. According to the method, topological optimization of the thermal structure of the anisotropic material is performed on the basis of the meshfree RKPM, the transformation matrix method and the RAMP material interpolation model, and the numerical stability is high.
Owner:XIANGTAN UNIV
Star sensor calibrating method based on star field
InactiveCN1948085AEliminate the effects ofWide applicabilityCosmonautic vehiclesCosmonautic partsNumerical stabilityLeast squares
A calibration method based on star field for the star-sensitive sensor includes such steps as creating a posture conversion array of star-sensitive sensor, creating the distortion model of star-sensitive sensor, and eliminating the least square parameters.
Owner:BEIHANG UNIV
Finite-element reconstruction method for space weighting of auto-fluorescence imaging
InactiveCN101539518AHigh speedSolving Quantitative Reconstruction Problems2D-image generationDiagnostic recording/measuringNumerical stabilityOptical tomography
The invention puts forward a finite-element reconstruction method for space weighting of auto-fluorescence imaging. The method uses a diffuse optical tomography (DOT) technique to precisely reconstruct optical parameters of main biological tissue. The method limits a possible real light-source region, and divides a whole reconstruction region into a light-source possible region and a light-source impossible region so as to improve the numerical stability and effectiveness of reconstruction problems and reduce the ill-conditioned property of BLT reconstruction problems. In order to avoid famous 'Inverse Crime' problems, the method adopts a Monte Carlo (MC) random method to simulate the process of transmitting light in the biological tissue. Then the invention puts forward a finite-element method based on a space-weighting unit and adopts a tolerant algorithm for linear constrained optimization problems to reconstruct light-source information.
Owner:INST OF AUTOMATION CHINESE ACAD OF SCI
Multi-robot cooperative positioning algorithm based on square root unscented kalman filter
InactiveCN104330083AAvoid approximation errorAvoid calculationNavigational calculation instrumentsNumerical stabilityComputation complexity
The invention provides a multi-robot cooperative positioning algorithm based on a square root unscented kalman filter. The multi-robot cooperative localization algorithm comprises the following steps: 1, providing a dynamic model for automatically positioning multiple moving robots according to kinematical equations of the robots and measurement equations based on relative positions; and 2, by adopting an SR-UKF filter algorithm, wholly updating the system state by taking the relative positions as input, thereby achieving cooperative positioning of the multiple moving robots. By adopting the algorithm provided by the invention, the positioning precision and the real-time requirements of a system can be both considered, the calculation complexness is reduced, the time of the algorithm is greatly shortened, the semi-positive definiteness and the value stability of a covariance matrix are ensured, and technical support is provided for cooperative positioning of later multiple moving robots.
Owner:NANJING UNIV OF SCI & TECH
Satellite relative attitude measuring method based on structure from motion
InactiveCN102607534ARealize identificationImplement trackingPicture interpretationNumerical stabilityStructure from motion
The invention discloses a satellite relative attitude measuring method based on a structure from motion. The satellite relative attitude measuring method includes a first step, respectively extracting SIFT (scale invariant feature transform) feature points of inputted sequence images; a second step, matching the obtained SIFT feature points; a third step, realizing the structure from motion according to the matched feature points; a fourth step, optimizing structural parameters of the structure from motion by a light beam adjustment method; a fifth step, carrying out three-dimensional reconstruction according to the matched feature points and the optimized structural parameters of the structure from motion; and a sixth step, comprehensively displaying a spatial environment according to effective three-dimensional feature points and the structural parameters of the structure from motion. By the aid of the satellite relative attitude measuring method, relative attitudes of an observed satellite target can be effectively measured according to standard test data, satellite simulation data of a STK (satellite tool kit) ontrack satellite simulation platform and ground semi-physical simulation data, and the measurement precision for constructing a system and stability of computed numerical values can be improved by the aid of the light beam adjustment method.
Owner:SHANGHAI JIAO TONG UNIV
Synchronous vector measuring device
ActiveUS7006935B2Improve continuityImprove stabilityPower measurement by digital techniqueEmergency protective arrangements for automatic disconnectionNumerical stabilityMeasurement device
A synchronous vector measuring device can measure an absolute phase angle of a synchronous vector excellent in continuous numerical stability at high speed and with high accuracy in a noisy electric power system. A voltage measuring part measures the voltage of the electric power system at a period equal to 1 / 4N (N being a positive integer) of one period of a reference wave. A voltage root-mean-square value calculation part calculates, at each voltage measuring timing, a voltage root-mean-square value at a specific timing from the voltages measured at past 4N timings including the specific timing. An absolute phase angle calculation part makes, at each voltage measuring timing, an inverse cosine of a value obtained by dividing the voltage measured at the specific timing by the product of the voltage root-mean-square value and the square root of 2, as the absolute phase angle of the synchronous vector at the specific timing.
Owner:MITSUBISHI ELECTRIC CORP
FastSLAM method based on particle proposal distribution improvement and adaptive particle resampling
ActiveCN106599368AImprove numerical stabilityHigh precisionDesign optimisation/simulationSpecial data processing applicationsKaiman filterNumerical stability
The invention discloses a FastSLAM method based on particle proposal distribution improvement and adaptive particle resampling. The method comprises the steps that 1, a square root transformation unscented Kalman filter is utilized to estimate optimal particle proposal distribution, and the pose state of a robot is sampled; 2, a square root volume Kalman filter is utilized to update feature map information corresponding to each particle; 3, an adaptive particle resampling method based on relative entropy is utilized to determine the quantity of particles needed at the current moment; 4, the pose stat of the robot and guidepost feature map information are determined according to a particle set obtained after resampling. A traditional FastSLAM algorithm is improved from the two aspects of quality and quantity of the sampling particles at the same time, thus, the numerical stability and accuracy of the algorithm in the estimation process are enhanced, and the quality of the sampling particles is improved; in the particle resampling process, the least quantity of the needed particles is dynamically determined according to estimation uncertainty, and therefore the calculation efficiency of the algorithm is improved.
Owner:ZHEJIANG UNIV
Power grid parameter error and bad data coordinated identification and estimation method
InactiveCN104836223AEfficient collaborative identificationPrecise collaborative identificationAc network circuit arrangementsNumerical stabilityEstimation methods
The invention discloses a power grid parameter error and bad data coordinated identification and estimation method relating to a calculating method of power grid parameter accuracy. The conventional parameter error identification and estimation technology is low in efficiency and accuracy. The method provided by the invention comprises the following steps: 1) read-in of a power grid model and a plurality of measurement sections; 2) one-by-one state estimation of the measurement sections; 3) suspicious parameter and measurement detection; when the related measurement total error is smaller than the threshold value, the parameters or the measurement can be trusted; when the related measurement total error is greater than the threshold value, the parameters or the measurement can be suspicious, and can be filed in the suspicious parameter / measurement set; 4)parameter / measurement error coordinated identification based on multi-section and total error reduction index; when the suspicious parameter / measurement total error reduction index is greater than 9, the data are the error parameters or the bad data; 5) multi-section combined parameter estimation. The power grid parameter error and bad data coordinated identification and estimation method is advantageous in that the measurement redundancy, the value stability, and the calculating efficiency can be improved, and the parameter error identification and estimation accuracy can be improved.
Owner:ZHEJIANG UNIV
Method for solving non-linear programming and absolute value equation through improved harmony search algorithm
InactiveCN103631758AFast convergenceFew parametersComplex mathematical operationsHarmony memoryNumerical stability
The invention discloses a method for solving non-linear programming and an absolute value equation through an improved harmony search algorithm. The method for solving the non-linear programming includes the steps of defining a question and parameter values, initializing a harmony memory bank, generating a new harmony by learning the harmony memory bank, finely adjusting embedded tones which are normally distributed and selecting the tones at random, evaluating a new solution, and detecting whether an algorithm end condition is met or not. The method for solving the absolute value equation includes the steps of defining a question and parameter values, initializing a harmony memory bank, generating a new harmony by learning the harmony memory bank, finely adjusting tones and selecting the tones, setting a probability WSR, selecting a harmony to be updated by comparing a random number Rand with the WSR, a new solution is evaluated, and detecting whether an algorithm end condition is met or not. According to the method for solving the non-linear programming and the absolute value equation, the non-linear programming and the absolute value equation are solved through the improved algorithm, and numerical stability and arithmetic speed and accuracy are improved.
Owner:SHAANXI UNIV OF TECH
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
Simulation method for controlling novel classic tearing mode through resonance magnetic disturbance in tokamak
ActiveCN110232205AGood combination experimentImprove computing efficiencyDesign optimisation/simulationSpecial data processing applicationsNumerical stabilityMagnetic disturbance
Owner:DALIAN UNIV OF TECH
Motion target tracking method of asynchronous wireless sensor network
InactiveCN101925178ALow hardware requirementsGuaranteed Tracking AccuracyNetwork topologiesLine sensorNumerical stability
The invention discloses a motion target tracking method of an asynchronous wireless sensor network, belonging to the technical field of a wireless network and comprising the following steps: establishing a wireless sensor network and performing network location initialization setting; and emitting signals once at an interval of L numbered clock periods, transmitting the corresponding measurement value to a sink node by each sensor node, and synthesizing a measurement vector by the sink node to be used for displacement evaluation and threshold updating. The method in the invention has good numerical stability, especially under the condition of low speed motion, maintains the precision of technical paper, and has good practical prospect in the sensor network with a larger distribution range.
Owner:SHANGHAI JIAO TONG UNIV
Interstellar cruising self-nevigation method based on multi-star road sign
The invention relates to the space cruising autonomous navigation method based on plural globe route sign. It includes the following steps: programming the navigation using minor planet table, processing navigation minor planet image, and determine the autonomous path. The center of figure of plural minor planet determines the path of craft. The error of craft path is very low. The location error could be closed to 100Km and the speed error could be bellow 0.3m / s. It could satisfy the path accuracy request of the detector.
Owner:HARBIN INST OF TECH
Method for estimating state of three-phase four-wire low-voltage distribution network
InactiveCN103532137AImprove performanceInhibit bad effectsAc network circuit arrangementsNumerical stabilityNetwork structure
The invention discloses a method for estimating the state of a three-phase four-wire low-voltage distribution network and belongs to the technical field of three-phase state estimation of distribution networks. The method comprises the following steps of firstly, by using a computer, inputting low-voltage distribution meter-reading electric data and a network structure which are acquired within any time section, and parameter information through a program, and initiating the data, the network structure and the parameter information; then calculating constant item parts of a node admittance matrix and a jacobian matrix; synthesizing a measuring equation and T-end point zero injection equation restriction, and taking a real part and an imaginary part of voltage as state variables to calculate unbalance amount, an index type weight function and the jacobian matrix; finally updating the state variables and performing astringency judgment to realize estimation on the state of the three-phase four-wire low-voltage distribution network. Active power and reactive power of a node can be independently calculated by the method, the adverse influence of bad data on an estimating result is prevented, and the method has the characteristics of high difference resistance, good astringency, good numerical stability and the like. The method is widely applied to the estimation on the state of the three-phase four-wire low-voltage distribution network.
Owner:CHONGQING UNIV
High-precision real-time stereoscopic visual positioning method utilizing parallax space bundle adjustment
ActiveCN102607535AReduce dependencyAutonomousUsing reradiationSteroscopic systemsNumerical stabilityStereo camera
The invention discloses a high-precision real-time stereoscopic visual positioning method utilizing the parallax space bundle adjustment. According to the invention, only a video streaming obtained by a stereo camera is utilized to carry out navigation positioning of a mobile robot, so that the high-precision real-time stereoscopic visual positioning method has complete autonomy; a U-SURF descriptor is utilized to carry out feature matching, so that the high-precision real-time stereoscopic visual positioning method has strong robustness on illumination variation, motion blur and large rotation and scale variation which are generated in the moving process; and due to the utilization of a parallax space bundle adjustment optimizing method, an autonomous navigation vehicle can also be subjected to accurate real-time positioning when traveling for a long distance, so that the high-precision real-time stereoscopic visual positioning method has the advantages of low degree of dependence on an optimal initial value, high convergence rate, high value stability and the like and compared with a stereoscopic visual positioning method utilizing the bundle adjustment, the high-precision real-time stereoscopic visual positioning method has higher positioning precision and higher speed. The integral stereoscopic visual positioning method disclosed by the invention has high calculating speed and can be operated on line in real time.
Owner:HUZHOU TEACHERS COLLEGE
Stable and accurate reactor physics thermotechnical coupling calculating method
ActiveCN106202866AAvoid the effects of iterative convergenceGuaranteed accuracySpecial data processing applicationsInformaticsNumerical stabilityApproximate computing
A stable and accurate reactor physics thermotechnical coupling calculating method can simultaneously obtain statuses of a neutronics field, a fluid field and a heat transfer field; all variables are simultaneously updated in an iteration process, so the method has better value stability when compared with a conventional coupling method; the method uses a simultaneous time-space neutron diffusion equation and a thermotechnical equation discrete equation to obtain a novel nonlinear equation group with larger scale; using a Newton iterative method to resolve values of the novel nonlinear equation group, wherein the Newton iterative method needs to calculate a Jacobian matrix of the equation group in each iteration step, so physics thermotechnical coupling calculation is difficult. The novel method builds a value relation between the diffusion equation and thermotechnical equation, and explicit calculation can provide the Jacobian matrix, so problems caused by approximation calculation f the Jacobian matrix can be prevented; in addition, the novel method inherits Newton method characteristics, and hopes to provide faster convergence speed.
Owner:XI AN JIAOTONG UNIV
Electric power system transient stability calculation method based on semi-implicit Runge-Kutta method
PendingCN110135031AEfficient, accurate and stable transient stability calculationEfficient, accurate and stable calculationDesign optimisation/simulationComplex mathematical operationsRunge–Kutta methodNumerical stability
The invention discloses an electric power system transient stability calculation method based on a semi-implicit Runge-Kutta method. The method includes: establishing a dynamic element model for transient stability simulation calculation of the power system; forming a whole system differential algebraic equation set; inputting raw data and information, carrying out tide calculation, obtaining an operation parameter initial value before system disturbance; calculating an initial value of the state variable; generating a Jacobian matrix and a network admittance matrix of each dynamic element; performing system disturbance judgment; generating a Jacobian matrix of the differential equation set of the whole system; solving and obtaining the value of each state variable at the next moment; carrying out machine network alternate iterative computation, obtaining an operation parameter value at the next moment until a convergence condition is met, and taking the operation parameter value as aninitial value to calculate the next step length. The calculation is simple and stable, the larger step length can be used, the problem that the numerical stability and the calculation efficiency of the algorithm are difficult to consider at the same time in the transient stability simulation calculation is solved, and the method is more efficient, accurate and stable.
Owner:SOUTHEAST UNIV
Robust digital audio watermark embedding and detection method based on polar harmonic transform
InactiveCN105632506AGood frequency domain localization featuresImprove numerical stabilitySpeech analysisNumerical stabilityDecomposition
The invention discloses a robust digital audio watermark embedding and detection method based on polar harmonic transform. Advantages of great frequency domain localization features, multi-scale, redundancy and translation invariance, the features of non-stationary of greatly describing signals and maintaining the shape of the signals and the same length of audio frequency of each sub-band after decomposition with that of the original audio frequency of nonsubsampled wavelet transform are utilized; then great numerical stability of polar harmonic transform is also utilized, and watermarks are embedded in stable torque values to resist the normal signal attack; and then the synchronization code technology is combined. The experimental results indicate that normal signal processing can be resisted and the desynchronization attack can also be effectively resisted so that the method has great imperceptibility and robustness. Besides, the method also has advantages of being simple in design and easy to realize.
Owner:LIAONING NORMAL UNIVERSITY
Statistical delay and noise calculation considering cell and interconnect variations
ActiveUS20090288050A1Efficiently delayEfficiently sensitivityAnalogue computers for electric apparatusComputation using non-denominational number representationNumerical stabilityEnvironmental variation
The electrical circuit timing method provides accurate nominal delay together with the delay sensitivities with respect to different circuit elements {e.g., cells, interconnects, etc.) and variational parameters (e.g., process variations; environmental variations). All the sensitivity computations are based on closed-form formulas; as a consequence, the method provides rapidly and at low cost high accuracy and high numerical stability.
Owner:SYNOPSYS INC
High speed high precision transient simulation method able to process tree net hybrid power supply structure in VLSI
InactiveCN1564321ASemiconductor/solid-state device manufacturingSpecial data processing applicationsNumerical stabilityCapacitance
The method is capable of carrying out transient state emulation for hybrid power supply network by mixing tree and network in any proportion quickly. Comparing with general emulation method, the invention can treat irregular topological structure and multiple power supply source, considering input of resistance, capacitance, and inductance as stray parameter so as to provide high precision of emulation. Pretreatment technique and quick argument elimination technique based on incomplete Cholesky decomposition is adopted in the invention. Advantages are: raising efficiency greatly, high precision of emulation and stability of data, emulation of network of power source / ground wires in large scale independent on topology. The invention is also applicable to passive clock line, bus and signal network in IC.
Owner:TSINGHUA UNIV
Implicit-projection-based method for simulating stability of active power distribution system
InactiveCN104156542AImprove performanceQuick solveData processing applicationsSpecial data processing applicationsNumerical stabilityIntegrator
The invention discloses an implicit-projection-based method for simulating the stability of an active power distribution system. According to an active power distribution system stability simulation model with the rigidity characteristics, based on system simulation parameters and load flow calculation results, the implicit-projection-based method includes the steps that firstly, a plurality of steps of small-step-length integral calculation are carried out through an internal integrator, wherein the step length is h, and any explicit integral algorithm with the accuracy higher than the second order can be adopted; secondly, a step of large-step-length integral calculation is carried out with the step length Mh through an external integrator based on an implicit prediction-correction method according to the calculation result of the internal integrator. By means of the implicit-projection-based method, simulating calculation of system faults can be achieved, the implicit-projection-based method is a second-order accuracy algorithm and has the good numerical stability, a numerical stability domain of the implicit-projection-based method is hardly changed along with changes of the multiple of the step length of the external integrator, the performance of the algorithm is better than that of the explicit projection integral algorithm and that of a traditional implicit trapezoidal method, the implicit-projection-based method is suitable for rapidly achieving the aim of simulating the stability of the active power distribution system with the multi-time scale characteristics, and a foundation is laid for efficiently and reliably developing an active power distribution system simulation program.
Owner:TIANJIN UNIV +2
Simulation method for evolution of electron cyclotron current profile in tokamak
ActiveCN108733946ASolve the problem that cannot reflect the real current profile evolution processAccurate descriptionDesign optimisation/simulationSpecial data processing applicationsNumerical stabilityTime evolution
The invention discloses a simulation method for the evolution of an electron cyclotron current profile in a tokamak. In the process of numerically simulating the evolution of the electron cyclotron wave drive current profile in the tokamak device, a drive current source is firstly described by using a Gaussian function; the evolution of the drive current under a specific magnetic field configuration is calculated according to a convection equation determined by a Fisch-Boozer theory; the magnetic field configuration under the correction of the drive current is calculated; the evolution of thedrive current continues to be calculated under the magnetic field configuration; and the simulation effect of long-term evolution is achieved through repeatedly calculating. The method disclosed by the invention has the beneficial effects that the evolution of the electron cyclotron wave-driven current profile under a real three-dimensional magnetic field configuration is realized; the drive current profile can be obtained at any time; in the meanwhile, the spatial distribution situation of the drive current can be more accurately described through the convection equation determined by the Fisch-Boozer theory; the calculation efficiency is high; the numerical stability is strong; and the method is a stable and efficient numerical simulation method.
Owner:DALIAN UNIV OF TECH
Self-adaption finite element light source reconstruction method based on simple spectrum or mix segment measurement
InactiveCN101292863AReduce morbidityBalanceDiagnostic recording/measuringSensorsNumerical stabilityMixed spectrum
The present invention discloses a self-adaptive finite element optical source rebuilding method based on single spectrum or mixed spectrum measurement. A prior feasible optical source area and a prior forbidden optical source area are confirmed by the optical characteristic parameter and the dissection structure information of a target rebuilding area. Partial gridding is optimized and decomposed by single spectrum or mixed spectrum light flux measurement data at the boundary of the target rebuilding area to be combined with multilevel self-adaptive finite element and a posteriori error estimation method, so as to obtain a fluorescent optical source inside the target rebuilding area. Therefore, based on the single spectrum or mixed spectrum boundary measurement data, the method of the present invention adopts the prior feasible optical source area to reduce the morbidity characteristic of bioluminescence tomography and ensures that the present invention can confirm the only solution; the self-adaptive finite element method is used for balancing gridding partitioning degree, algorithm efficiency and value stability and the partial gridding is optimized according to the posteriori error estimation, which improves quality, efficiency and robustness of the fluorescent optical source rebuilding.
Owner:INST OF AUTOMATION CHINESE ACAD OF SCI
Power distribution network fault positioning method based on algebraic relation description and complementary theory
InactiveCN105929306AGet rid of dependenceAchieve positioningFault location by conductor typesFault toleranceNumerical stability
The invention discloses a power distribution network fault positioning method based on algebraic relation description and the complementary theory, and the method comprises the following steps: collecting current out-of-limit information of each feed switch of a power distribution network through employing a main station, defining current state characteristic values of the switches, and determining whether each feed line has a permanent fault or not through employing the current state characteristic values of the switches; carrying out the positioning of a feed line fault segment according to the current state characteristic information uploaded by the feed switches; enabling the main station to send a switching-off command to an automatic switch at the feed line fault segment according to the positioning result of the feed line fault segment. The method employs algebraic relation modeling and an approaching relation theory. Compared with a matrix method, the method is easier for the consideration of fault tolerance, gets rid of dependence on a swarm intelligence algorithm based on logic relation modeling optimization fault positioning method, can employ conventional linear optimization to achieve the positioning of the feed line fault region, is good in numerical stability, is higher in fault positioning efficiency, and is suitable for the online fault positioning of a large-scale power distribution network.
Owner:HENAN INST OF ENG
Background grid adaptive segmenting method in DC resistivity no-unit method
InactiveCN108287371AImprove computing efficiencyImprove numerical stabilityElectric/magnetic detectionAcoustic wave reradiationElectricityNumerical stability
The invention provides a background grid adaptive segmenting method in a DC resistivity no-unit method. The method comprises the following steps of determining distribution condition of medium, abnormal member, landform, electrode and the like in a two-dimensional ground electric model, establishing a DC resistivity no-unit method calculating domain, and utilizing an irregularly distributed node discrete ground electric model; covering the calculating domain by means of a small number of rough and simple initial quadrangular grids, setting a control value which guides adaptive segmentation, and performing adaptive segmentation by the background grid according to the control value and a node distribution condition; arranging ng Gaussian integration points xg in each background grid, and obtaining a no-unit method equation set of the region; solving the equation set for obtaining a node electric field value, and calculating the vision resistivity parameter of a viewing point. The methodcan be based on any node distribution discrete model. High adaptability for any complicated ground electric model is realized. The background grid adaptive segmenting method improves value stability and computing efficiency in routine DC resistivity no-unit method forward calculation.
Owner:CENT SOUTH UNIV
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