Patents
Literature
Patsnap Copilot is an intelligent assistant for R&D personnel, combined with Patent DNA, to facilitate innovative research.
Patsnap Copilot

105 results about "Density method" patented technology

Method for extracting contour and corner of building from ground LiDAR data

The invention relates to a method for extracting a contour and a corner of a building from ground LiDAR data. At first, a hierarchical grid density method is adopted to extract the contour of the building from the ground LiDAR data; then a contour extension density method is adopted to restore the extracted contour of the building to obtain the complete contour of the building; and when a corner needs to be extracted, the complete contour of the building is projected into an XY plane with a three-dimensional coordinate system to seek a two-dimensional intersection point, and if the elevation difference of contours of intersection points of any two lines is less than 1m, two contours can be judged to be intersected in the actual three-dimensional space, the intersection point of the two contours is a ground corner, and the average of the elevations of the two contours can be used as the elevation of the ground corner. By adopting the grid density method, the method for theoretical estimation and determination of the grid density threshold and the contour density extension method, the accurate contour segment of the building and the precise ground corner can be extracted from the ground LiDAR data. Moreover, automated extraction can be realized, and the efficiency of data processing can be improved greatly.
Owner:NANJING UNIV

Method for fast predicting organic pollutant n-caprylic alcohol/air distribution coefficient based on molecular structure

The invention discloses a method for fast predicting organic pollutant n-caprylic alcohol/air distribution coefficient based on molecular structure, belonging to the technical field of quantifying structure/active relationship (QSAR) facing to the environmental risk evaluation. The method is characterized of comprising the steps of: adopting the molecular structure of atomic center fragment characterization compound; and screening the atomic center fragment combination by means of stepwise regression and partial least-squares regression, to build a group contribution model for predicting KOA.The internal authentication and the external authentication improves that the built KOA group contribution model has stability and predicting capability, and a range and distance method and a probability density method express the application domain of the group contribution model, thereby defining the application range of the model and guaranteeing the predict accuracy. The method has the effectsand benefits of being capable of fast predicting the KOA of the high flux compound, obtaining the KOA with low cost, being helpful for obtaining the high flux KOA data, and having a significant meaning for the environment supervision and the risk evaluation of chemicals.
Owner:DALIAN UNIV OF TECH

Topological optimization design method for high-speed vertical machining centre long-span beam

The invention belongs to the technical field of mechanical design and relates to a topological optimization design method for a high-speed vertical machining centre long-span beam. The method is mainly for the topological optimization of the three-dimensional solid structure of the long-span beam. The method consists two parts of early basis analysis and topological optimization design; the early basis analysis is to grasp the static and dynamic properties of the original beam, find out the parts of relatively weak static and dynamic properties and perform structural topological optimization on the beam correspondingly; and in the later topological optimization design, based on the result of the basic analysis, the later structural topological optimization including two-dimensional topological optimization and three-dimensional topological optimization of the beam is performed according to the characteristics of the beam. In the topological optimization method, a density method is adopted, the volume fraction response is used as a constraint function, and the static strain energy response is used as a target function; and finally an innovative model is established again according to the results of the two-dimensional and three-dimensional topological optimization analysis. The structural topological optimization method has the advantages of improving the optimization efficiency, along with accurate and reliable optimized results.
Owner:DALIAN UNIV OF TECH

Variable-density porous metal orthopedic implant preparation method based on topology optimization technology

The invention discloses a variable-density porous metal orthopedic implant preparation method based on a topology optimization technology. The method comprises the steps that a bone geometric model isestablished through CT scanning, a microstructure is selected, and the porosity, the pore size of the microstructure and wall thickness conditions of the microstructure serve as constraint conditionsof topology optimization; attributes of an equivalent entity unit are calculated through a homogenization method, and a finite element is used for calculating the chemical performance of an implantedthrough the equivalent entity unit; the density distribution in the implant area is obtained through the density method topology optimization technology, and the porosity, the pore size of the microstructure and the wall thickness conditions of the microstructure serve as constraint conditions of topology optimization; a geometric model of the variable-density gradient porous orthopedic implant is constructed on the basis of the position information of a finite element node unit; the variable-density porous metal orthopedic implant is manufactured through 3D printing processing. The bone absorption is low, the mechanical property is good, the service life is long, and the probability of correction operations after the implant is implanted for a period of time can be reduced.
Owner:SOUTH CHINA UNIV OF TECH

Comprehensive detection method of composite insulator aging degree

The invention provides the comprehensive detection method of a composite insulator aging degree. The method is characterized by through obtaining the measuring results of an infrared spectrum analysismethod, a thermal stimulation current TSC analysis method, a hyperspectral spectrogram analysis method and a surface charge density method, using an BP neural network algorithm to optimize differenttest methods to acquire the weight of a test result; obtaining the comprehensive aging degree of a composite insulator; and acquiring the remaining service life of composite insulator aging through anormalization method. The aging degree of the composite insulator is acquired through integrating various methods, the comprehensive detection of the aging degree of the composite insulator is realized, the aging degree of the composite insulator can be accurately measured, and the remaining service life of the composite insulator is predicted. More accurate technical support is provided for the operation and maintenance personnel of a power transmission line to timely replace the composite insulator with the severe aging degree, and the safe and reliable operation of the power transmission line is ensured.
Owner:YUNNAN POWER GRID CO LTD ELECTRIC POWER RES INST

Viscous fluid modeling method based on SPH method approximate solution

ActiveCN108269299ASolve the clustering phenomenonRich sports sceneDesign optimisation/simulationAnimationReal-time simulationFluid viscosity
The invention discloses a viscous fluid modeling method based on SPH method approximate solution. An N-S equation is firstly simplified according to the characteristics of a particle system method; then, according to the simplified equation, a framework for simulating a viscous fluid is built; and then, according to the simulation framework, each physical quantity is subjected to approximate solution based on an SPH method. a corresponding pressure term in the N-S equation is solved approximately through a pressure-density method, and the problem that strict time step constraints exist when the SPH method simulates the viscous fluid is solved; and besides, the phenomenon of particle clustering in a fluid motion process is solved. Through building a spring model, that is, adding, modifyingand deleting springs between adjacent particle pairs, viscoelasticity of the fluid motion is realized; and through influences on the relative velocity of particles by introduced temperature, influences on the fluid viscosity by the temperature are thus described. Compared with the traditional method, the method of the invention has the advantages that the calculation is simple; real-time simulation can be realized basically; and the viscous fluid motion scene can be simulated more vividly.
Owner:BEIHANG UNIV

Industrial robot joint rigidity modeling method which considers contact

ActiveCN107545127AAccurate Theoretical Estimation of Joint StiffnessProgramme-controlled manipulatorSpecial data processing applicationsContact pressureAnalysis study
The invention discloses an industrial robot joint rigidity modeling method which considers contact, and belongs to the field of industrial robot dynamic characteristic analysis study. By extracting key contact structure characteristics of each industrial robot joint, contact structures are assumed to be spring structures with a certain torsional rigidity, and an equivalent system model of all thejoints is built. According to measurement data, based on a power spectrum density method, three-dimensional surface fractal parameters and surface roughness parameters are calculated. All the contactstructures are subjected to stress analysis, and all contact pressure values corresponding to different joint input torques of the contact structures are calculated. By building an equivalent torsional rigidity model of springs in parallel connection and by making all contact rigidity and a reducer rigidity connected in parallel, a joint equivalent torsional rigidity is calculated. Through the combination of a fractal theory and structural stress analysis, an industrial robot joint rigidity model is built, by considering a contact rigidity, a more accurate theoretical estimation joint rigidityis calculated, and a certain method basis is provided for dynamic error compensation analysis at the tail end of the robot.
Owner:BEIJING UNIV OF TECH

Multi-dimension background modeling method based on combination of textures and intensity characteristics

ActiveCN102222339AOvercome the voidOvercome the problem of lighting changesImage analysisClosed circuit television systemsPattern recognitionSelf adaptive
The invention discloses a multi-dimension background modeling method based on combination of textures and intensity characteristics. The method comprises the following steps: performing multi-dimension conversion on the input image sequences; representing the image in each dimension by using the same-dimension centrally symmetrical partial ternary mode operator; calculating the probability that the mode in each dimension image belongs to the background by using the self-adaptive mode kernel density method; regarding the probability density distribution with the accumulated weight exceeding the texture proportional threshold as the background, and calculating the probability that the mode belongs to the background; representing the intensity image of each dimension as the intensity image; regarding the Gaussian model with the accumulated weight exceeding the intensity proportional threshold as the background; calculating the probability that the intensity value belongs to the background by using the simplified mixed Gaussian model; mixing the image textures and image intensities with the same dimension; mixing the images with different dimensions so as to obtain the final probability belonging to the background; when the probability is greater than the background division threshold, belonging to the background; and on the contrary, belonging to the foreground.
Owner:INST OF AUTOMATION CHINESE ACAD OF SCI

Method for measuring normal temperature resistivity and resistance temperature coefficient of conductor at variable temperature

The invention relates to a method for measuring the normal temperature resistivity and the resistance temperature coefficient of a conductor at variable temperature. The method is characterized by installing a two-point electronic temperature measurement probe on a standard bridge test stand, introducing a microhmmeter measuring signal and an electronic temperature measurement probe signal into a computer acquisition card, simultaneously and continuously recording resistance values and temperature changes by using a computer, changing the room temperature by using an indoor air-conditioning device, computing the resistivity by using the recorded resistance values at different temperature and the cross section area measured by a density method, obtaining the variable linear slope K of a resistor R relative to temperature T according to a fitting curve, and computing the slope K by using a resistivity temperature variation coefficient [alpha]. The method uses a universal measuring bridge with the electronic temperature probe and the air conditioner temperature change so as to solve a puzzle in common laboratory conductor resistivity and temperature coefficient measurement, and is simple in measurement procedures and high in efficiency compared with a standard measuring method.
Owner:STATE GRID HEBEI ELECTRIC POWER RES INST +2

Component topology optimization design method for complex assembly

InactiveCN102880761ASpecial data processing applicationsElement modelTruss topology optimization
The invention relates to a component topology optimization design method for a complex assembly, and aims to solve the problem of difficulty in the determination of boundary conditions in a topology optimization design process for components of the complex assembly. The method comprises the following steps of: establishing and analyzing an assembly finite element model, and extracting and exporting the boundary conditions of a sub-structure which is a component to be optimized in the assembly model; loading the extracted boundary conditions onto the component to be optimized, and performing topology optimization on the component by utilizing a density method; when a change in the size of an optimization object exceeds a preset value, re-extracting the boundary conditions of the component, and continuing performing the topology optimization on the component; and when the optimization object is consistent with an iteration stopping condition, stopping optimization iteration to obtain a final optimal structure. An accurate optimal structure of the component can be obtained by accurately determining the boundary conditions of the component, and the problems of a plurality of design variables, inaccurate contact definition of combination parts between components and large calculated amount caused by the direct adoption of the assembly for the topology optimization design are solved.
Owner:UNIV OF SHANGHAI FOR SCI & TECH

Structural topology optimization method based on material field reduction stage expansion

The invention discloses a structure topology optimization method based on material field reduction series expansion, and solves the problem of low calculation efficiency caused by too many design variables and need of relative density or sensitivity filtering measures in traditional density method topology optimization. The method comprises the following steps: a bounded material field consideringcorrelation is defined; a spectral decomposition method is adopted to perform transform to obtain a linear combination of a series of undetermined coefficients, the undetermined coefficients are usedas design variables, an optimization model is constructed based on a unit density interpolation model, a gradient class or non-gradient class optimization algorithm is adopted to solve a topologicaloptimization problem, and then a topological configuration with a clear boundary is obtained efficiently. According to the method, the number of design variables in density method topology optimization can be greatly reduced, and meanwhile, the method has the natural advantage of completely avoiding grid dependence and chessboard format problems. The method also inherits the advantages of simple density method form, convenience in engineering popularization and the like, the optimization solving speed is high, and the research and development efficiency of the innovative topological design ofthe complex equipment structure can be ensured.
Owner:DALIAN UNIV OF TECH

Micro-surfacing mixture mineral aggregate grading optimization design method

The invention discloses a micro-surfacing mixture mineral aggregate grading optimization design method. The method comprises the following steps of 1) determining different mineral aggregate grading schemes through the throughput of key sieve holes; 2) determining the stacking density of each scheme of the different mineral aggregate grading schemes; 3) performing initial performance testing on different graded mineral aggregates; 4) determining physical and mechanical indexes of the different graded mineral aggregates; 5) performing road performance examination on the different graded mineral aggregates; 6) determining micro-surfacing mixture optimal mineral aggregate grading. According to the method disclosed by the invention, the quality of the micro-surfacing mixture mineral aggregate grading is judged by adopting an aggregate stacking density method, so that a micro-surfacing mixture with a dense framework structure is obtained; moreover, the earlier-stage and later-stage road performances of the micro-surfacing mixture are comprehensively considered, so that a micro-surfacing mixture with great high temperature stability, skid resistance and relatively high abrasion resistance is obtained. According to the design method provided by the invention, test data is accurate and reliable; by referring to a testing method for a hot-mixed asphalt mixture, the popularization value is very good.
Owner:CHANGAN UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products