47results about How to "Avoid iterative calculations" patented technology

The invention discloses a life evaluation method for a modular multilevel converter (MMC). The life evaluation method comprises the following steps: reading year-round temperature data of a running natural environment of the MMC and power data input into the MMC; performing analytic calculation on the average value and the effective value of the current of sub-modules IGBT and Diode of the MMC; calculating the average loss power Ploss,T and Ploss,D of the sub-modules IGBT and Diode of the MMC within the fundamental frequency period; calculating the average temperature rise Tja of a semiconductor device within the working frequency period by use of a Forster network model to obtain the average junction temperature value Tj of IGBT modules (IGBT modules, IGBTs, including IGBT and Diode); modifying fitting calculation of loss of the IGBTs according to the average junction temperature of the IGBTs; calculating the extreme values of the function temperature within the working frequency and counting the year-round fundamental frequency junction temperature cycle; counting fluctuation information of the year-round low-frequency junction temperature; and calculating the failure number Nf of the fundamental frequency and the low frequency of the semi-conductor device by use of a Bayerer life model, and obtaining the life of the MMC in combination with operation conditions. The life evaluation method can reliably forecast the life of the MMC, can effectively improve the forecasting calculation speed through obtaining an analytical expression of both current and the junction temperature, and has the characteristics of project operational capability and the like.

The invention discloses a rapid spectrum stabilization method for a ray energy spectrometer, comprising the following steps: adopting the quadratic curve to fit the envelope curve of the characteristic peak of the ray energy spectrum; computing the axis of symmetry of the envelope curve to compute the peak channel CP of the characteristic peak of the ray energy spectrum; and adaptively compensating the spectrum drift amount of the peak channel CP relative to the peak channel of the standard spectrum to correct the peak channel CP, thereby realizing spectrum stabilization. In the step of peak searching, zygomorphy and the characteristic of the quadratic curve are adopted to search for the peak channel CP and the quadratic curve is characterized by only having unique extreme point, thus greatly reducing the amount of computation. In the step of correction, the adaptive adjustment algorithm is adopted to gradually change the parameter of gain or high pressure to achieve the aim of eliminating spectral drift. Therefore, the method has the advantages of fast update speed and high computation accuracy. The invention also discloses a rapid spectrum stabilization device corresponding to the method, comprising a curve fitting module, a peak searching module and a correction module. The device adopts the digital logic structure design of parallel computing, thus greatly improving the computing speed.

The invention relates to a keyword-based RDF distributed semantic search method. The method comprises the steps of constructing a semantic feasible path of input query keywords based on an RDF ontology; performing score sorting according to semantic content and a semantic structure of query content in the construction stage; generating Top-k semantic feasible paths; and performing a parallel search by utilizing a MapReduce computing framework and returning Top-k query results. According to the keyword-based RDF distributed semantic search method proposed by the invention, the semantic feasible paths are constructed and searched for based on the ontology and interconnection paths among the query keywords are determined, so that time-consuming iterative computing directly on a large-scale RDF data map is avoided; and parallel computing is realized by utilizing a MapReduce computing model, so that the overall computing complexity is effectively lowered for improving query performance.

The invention provides a non-iterative blind phase noise compensation method suitable for a CO-OFDM system. Non-iterative operation is performed via an approximation cost function and the CPE rough estimation value of each OFDM symbol is calculated, then the residual CPE estimation value is calculated by using a decision-directed phase equalization algorithm (DDPE), and finally phase noise compensation is completed. The cost function is introduced in calculation of the CPE rough estimation value, and the form includes the real part and the imaginary part of the frequency domain data of certain OFDM symbol after rotation of any angle. The cost function is perfectly approximated to a new cost function with a cosine function expression form, the rotation angle value is obtained when the new cost function takes the minimal value, and the rotation angle value is the CPE rough estimation value of the OFDM symbol. The invention provides the non-iterative blind phase noise compensation method suitable for the CO-OFDM system, and the non-iterative blind phase noise compensation method suitable for the CO-OFDM system is relatively high in frequency utilization rate, relatively low in complexity, low in the requirement for hardware resources, and high in practicality.

The invention provides an oil deposit well pattern and injection-production scheme optimum design method based on a balanced water drive idea. The method comprises the steps of 1, collecting and arranging block geological and development related data; 2, setting optimizing related parameters, and completing the well pattern and injection-production optimization preparation work; 3, adopting an oildeposit engineering method, predicting the displacement condition on each direction under current well location and injection-production parameters and performing quantitative evaluation; 4, adoptinga global random search algorithm, optimizing and generating novel well location/injection-production parameters, and predicting and evaluating the displacement condition in each injection-productiondirection under novel well location injection-production parameters; 5, arranging the optimization result, forming a well pattern injection-production design scheme, and performing on-site implementation. According to the method, the water drive development index calculation method built on the basis of the oil deposit engineering idea is combined with the optimization theory, the global random search algorithm is adopted for automatic solving, the calculation efficiency is ensured while the well pattern and injection-production scheme matched with the actual oil deposit is obtained, and the oil deposit recovery efficiency is improved.

The invention discloses a discrete state event-driven simulation method for power electronic hybrid system simulation. Based on the hybrid characteristics of a power electronic system, a simulation method is designed for a continuous state and a discrete event coexisting in the power electronic system. The simulation method comprises a flexible adaptive algorithm with variable order and step sizeand an event-driven mechanism which automatically triggers simulation calculation through the discrete event. The continuous state is described by a state variable method. The discrete event is defined as a trigger source of simulation calculation. The discrete state event-driven simulation method for power electronic hybrid system simulation solves the problems of large simulation computation andlong time of a complex power electronic system under the premise of ensuring accuracy.

The invention discloses a three-dimensional indoor localization method utilizing visible light communication. Any number of light emitting diodes (LEDs) are placed indoors, and any number of photodiodes (PDs) are arranged on target terminal equipment as light receiving devices. Supposing that the coordinate locations and transmitting power of the LEDs are known, the PDs and a target terminal are on the same level and the relative locations of the PDs and the target terminal are known, and by measuring the receiving power of each receiving device PD, the three-dimensional coordinate location of the target terminal can be determined through computation by utilizing the geometrical relationship. The method achieves indoor three-dimensional space localization, is small in computing quantity and high in precision and is suitable for common electronic mobile terminal equipment, such as mobile phones and tablet personal computers.

The invention relates to a linear real-time estimation method of a conductivity resistance-capacitance network parameter, belonging to the technical field of solution conductivity soft measurement. The method is characterized by comprising the following steps of: converting the measurement of solution conductivity into the parameter estimation of an equivalent resistance-capacitance network: on the basis of a mathematical model between a square wave excitation signal, a response direct-current voltage signal and two resistance and capacitance parameters of the equivalent resistance-capacitance network, carrying out multi-element polynomial fitting on the non-linear model off line; adopting an alternating-current square wave excitation resistance-capacitance network of various frequencies by taking the existence of various uncertainties into account during on-line measurement; meanwhile, establishing an over-determined equation set by utilizing the off line fitted multi-element polynomial model; and obtaining the real-time estimation of a resistance-capacitance parameter through a Gauss elimination finite step arithmetic operation and a radical operation of quartic equation solving on the basis of linear least square principle. The method has the advantages of higher estimation speed and stronger anti-jamming capability and is suitable for the on-line real-time accurate measurement of the conductivity industry.

Provided are a method for simulation modeling of a variable crown elevation tailwater tunnel water turbine regulating system and a model. The method comprises a step 1) of establishing a water turbine speed regulator mathematical model which comprises a water turbine speed regulator, namely a proportion integration differentiation (PID) regulator model, and an electrical-hydraulic servo system model; a step 2) of establishing a water turbine mathematical model; a step 3) of establishing a water conveyance system mathematical model, which concretely comprises the steps of performing segment handling on a water conveyance system, taking a water turbine as the boundary to divide the whole water conveyance system into a pressurized water conveyance system and a variable crown elevation tailwater system; respectively performing pressurized water conveyance system modeling and variable crown elevation tailwater system modeling; and obtaining a mathematical model of a whole water conveyance system according to the two mathematical models; and a step 4) of obtaining a simulation model of the whole variable crown elevation tailwater tunnel water turbine regulating system by combination with the water turbine speed regulator mathematical model established in the step 1), the water turbine mathematical model established in the step 2) and the water conveyance system mathematical model established in the step 3). The model established according to the method is small in calculated amount, the accuracy is high, and the stability is good.

The invention provides a power distribution network planning method considering reliability constraints, and belongs to the technical field of power system planning and evaluation. According to the method, a power distribution network planning model composed of an objective function and constraint conditions is constructed; the reliability index is incorporated into the power distribution networkplanning problem as a constraint, and the reliability index is accurately described through the coupling relationship between the constraints, so that the solution obtained by solving the power distribution network planning model inevitably meets the set reliability constraint, and an optimal power distribution network planning scheme is obtained. According to the method, a power grid planning scheme meeting the reliability constraint is directly obtained instead of adopting an iterative solution mode of firstly planning and then verifying the reliability index in a traditional power distribution network planning method, so that the optimality of the planning scheme is ensured, and meanwhile, the calculation time of power distribution network planning is greatly reduced.

The invention discloses a single lens space change image restoration method based on an Encoder-Decoder depth learning model. According to the method, firstly, an intelligible image and fuzzy image pair corresponding to a single lens is acquired, a single lens space change data set is constructed, an Encoder-Decoder depth learning model for end-to-end image restoration is constructed, the constructed data set is utilized to train the Encoder-Decoder depth learning model to acquire the trained Encoder-Decoder depth learning model corresponding to each space change image block, for a fuzzy imagenewly shot by the single lens, the fuzzy image is divided into blocks, each fuzzy image block is directly inputted to the corresponding trained Encoder-Decoder depth learning model, and lastly, the restoration result of each Encoder-Decoder depth learning model is spliced to form a final restoration image. The method is advantaged in that individually estimating PSF of the single lens is not needed, plenty of optimization iteration of the method in the prior art can be avoided, the image processing speed is fast, aberrations and chromatic aberration of the single lens can be further corrected, and the method is suitable for actual application.

In order to solve the technical problems that according to an existing endoscopy imaging technology, the size of a probe is large, the application requirement cannot be met, and when focusing spot scanning imaging is adopted, due to point-by-point scanning, repeated iterative computation and repeated access peripheral, the time spent in forming batched focusing spots is long, the invention provides an endoscopy imaging system and method based on single multimode fiber. The system comprises an illumination system, a light field measuring system and a computer processing system; the illuminationsystem comprises a laser, an optical attenuator, a collimating and beam expander and a first line polarizing film which are arranged in sequence; the light field measuring system comprises a beam splitter, a reference arm, an objective light arm, a second line polarizing film and a camera; the reference arm is composed of an optical phase shifter; the objective light arm comprises a focusing objective lens and the single multimode fiber; the computer processing system is used for controlling an optical phase shifter and a camera, an interference light field is demodulated through the phase shifting interference method, an objective light composite light wave electric field is obtained, and imaging is performed.

The invention provides an online monitoring system and method of an exhaust steam enthalpy value of a low pressure cylinder of a steam turbine. The system is provided with sensors at the positions corresponding to a steam pipeline of a condenser, an axis heater, and four groups of low pressure heaters where steam is exhausted by the low pressure cylinder. As monitoring for flow of circulating water and temperature of inlet water and outlet water is added, the heat of the exhaust steam of the low pressure cylinder can be calculated indirectly through a cold end system; when a heat balance equation is built for a condenser of a steam turbine thermodynamic system to calculate the exhaust steam heat of the low pressure cylinder, the heat which is taken away by the circulating water system andcan be measured directly is introduced to the balance equation, building of the heat balance equation is greatly simplified and accumulated error caused by a traditional calculation method is avoided.The monitoring system only monitors parameters of a low pressure heater system and parameters of a cold end system, calculation parameters are reduced to the maximum extent, and the calculation precision of the exhaust steam enthalpy value of the low pressure cylinder can be improved efficiently.

The invention discloses a hypersonic speed super-combustion stamping engine real-time model. A simplified shock wave angle calculation method is adopted for the real-time model; an aircraft forebody and a super-combustion stamping engine air inlet are further regarded as an integrally-coupled forebody /air inlet; air flow in an isolation segment is regarded as uniform cross-section friction pipe flow; the volume effect of a combustion chamber is considered, and the combustion chamber is regarded as a cavity; an engine tailpipe and an aircraft afterbody are integrally coupled, and flow of fuel gas in the coupled body is regarded as variable cross section friction pipe flow; accordingly a combustion chamber outlet parameter is represented by a first-order ordinary differential equation based on a volume dynamic principle. The invention further discloses a simulation method of a hypersonic speed super-combustion stamping engine and a control law design method, compared with the prior art, the dynamic process of the hypersonic speed super-combustion stamping engine can be accurately reflected, a solution is easy to obtain, and the real-time property is better.

The invention provides a high energy efficiency power distribution method in a distributed antenna system. The method comprises the steps that the maximum energy efficiency of the distributed antenna system is used as the optimization target; the power of each remote antenna of the distributed antenna system is used as an optimization variable to construct an energy efficiency model; derivative analysis and classified discussion are used to select the number of remote antennas used for signal transmission; and classified discussion and the Lambert function are used to give the closed expression of power distribution. The method provided by the invention can effectively realize the optimal power distribution of each remote antenna, provides the closed solution to avoid iterative computation, and has the advantage of greatly reduced computational complexity compared with the existing method.

The invention discloses a wireless broadband communication system station distribution networking method and system based on a clustering algorithm, and the method comprises the steps: calculating a cluster center of a signal uncovered region in a map through a k-means algorithm in each iterative calculation, and improving the signal coverage of the uncovered region based on the fact that a base station moves to the cluster center of the uncovered region. The position of only one base station is moved in each iterative calculation according to an agreed movement rule so as to achieve the purpose of improving the signal coverage rate. Multiple iteration simulation calculations show that each iteration step can achieve the purpose of increasing the coverage rate, and finally the algorithm is converged to a better result. The physical significance of a scene can be closely combined, a result which is not less than that of a traditional site optimization method is finally obtained, but the operation speed is ahead of that of the traditional optimization method.

The invention discloses an SAR echo signal simulation method based on a quasi-double-station model. The SAR echo signal simulation method comprises the following steps: inputting simulation parameters, and carrying out parameter initialization, wherein the simulation parameters include an antenna phase center triaxial coordinate track [X(ti), Y(ti) and Z(ti)] under an earth-fixed coordinate system, a ground target coordinate [xk, yk and zk], a squint angle phi(ti), a look-down angle phi(ti), and a simulation moment tM; calculating a distance vector between an antenna phase center to each ground target at each pulse emission moment, pulse receiving moment and pulse transceiving moment according to the simulation moment; and finally, combining with a mathematic model of an SAR echo signal, so as to obtain corresponding echo data. According to the method, the high-precision SAR echo simulation can be realized based on the quasi-double-station model and a continuous motion model of a radar; the complicated iterative computation is omitted, and very high computation efficiency is realized when the computational accuracy is guaranteed; and the SAR echo signal simulation method is applicable to onboard and satellite-bone SAR echo signal simulation, and the echo simulation of the SAR echo signals under various conditions can be finished.

The invention provides an analytical method for water level analysis of a critical reservoir of a partially submerged homogeneous slope. A hypothetical arc destruction mechanism employs closed solutions, a slope safety coefficient explicit expression is obtained by considering the overall moment balance of a soil body between a slope surface and a sliding surface, an optimization calculation mainprogram, an objective function subprogram and a constraint function subprogram are compiled for calculation through a built-in fmincon multidimensional constraint optimization algorithm of Matlab, a critical circle center is found, and the safety coefficient is solved. The method belongs to a statically determinate problem, the obtained calculation formula is an explicit expression, the formula issimple, the reason causing the critical reservoir water level can be reflected, the influence of the water level change on the stability of the partially submerged slope can be better understood, andthe defects of other existing methods are overcome.