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14 results about "Geometric analysis" patented technology

Geometric analysis is a mathematical discipline where tools from differential equations, especially elliptic partial differential equations are used to establish new results in differential geometry and differential topology. The use of linear elliptic PDEs dates at least as far back as Hodge theory. More recently, it refers largely to the use of nonlinear partial differential equations to study geometric and topological properties of spaces, such as submanifolds of Euclidean space, Riemannian manifolds, and symplectic manifolds. This approach dates back to the work by Tibor Radó and Jesse Douglas on minimal surfaces, John Forbes Nash Jr. on isometric embeddings of Riemannian manifolds into Euclidean space, work by Louis Nirenberg on the Minkowski problem and the Weyl problem, and work by Aleksandr Danilovich Aleksandrov and Aleksei Pogorelov on convex hypersurfaces. In the 1980's fundamental contributions by Karen Uhlenbeck, Clifford Taubes, Shing Tung Yau, Richard Schoen, and Richard Hamilton launched a particularly exciting and productive era of geometric analysis that continues to this day. A celebrated achievement was the solution to the Poincaré conjecture by Grigori Perelman, completing a program initiated and largely carried out by Richard Hamilton.

Three-dimensional modeling method for correlation of coal permeability and pore and fracture evolution

The invention provides a three-dimensional modeling method for correlation of coal permeability and pore fracture evolution, and relates to the technical field of three-dimensional modeling of a coal structure. Gray standardization, classification marking and spatial structure unit identification are carried out on all voxels at each moment, and voxel-level parameter statistics and geometric analysis are combined, so that the three-dimensional modeling method for correlation of coal permeability and pore fracture evolution is realized. According to the method, the porosity, the fracture width, the fracture connectivity and other structural characteristic parameters can be extracted and are dynamically paired with synchronously acquired physical field parameters, so that the physical accuracy and the time sequence response capability of the parameters are ensured, the accurate assignment of voxel-level parameters is also realized, the coal body heterogeneity and the dynamic evolution process are meticulously quantified, and the coal body quality is improved. The voxel scale permeability calculation method is adopted, the permeability value of each voxel can be calculated at each moment according to the voxel characteristic parameters and the physical field parameters, permeability distribution in a three-dimensional space is generated, and the structural evolution process of a coal rock core sample can be comprehensively captured.
Owner:INFORMATION RES INST OF EMERGENCY MANAGEMENT DEPT

Gas ultrasonic gas flowmeter and measurement method thereof

ActiveCN122108287BFeature extractionPhase space
This invention relates to the field of flow measurement and industrial process control technology, specifically to a gas ultrasonic flow meter and its measurement method; it includes a measurement pipe section, signal acquisition, phase space reconstruction, symplectic geometric analysis, and adaptive solution modules; the system acquires the original acoustic time-series signal and maps it into a high-dimensional state trajectory matrix; its core is to use symplectic geometric transformation to extract dynamic invariants such as the maximum Lyapunov exponent, determine the flow field distribution correction coefficient, and compensate the basic flow velocity to generate a standard flow rate; this invention transforms a complex inverse fluid mechanics problem into a geometric topology feature extraction problem, eliminating the need for massive model training, significantly reducing computational power consumption, and solving the computational deadlock problem.
Owner:NINGBO LIQING ULTRASONIC TECH CO LTD

Double-arc ball screw raceway section error identification method

The invention discloses a biarc ball screw raceway section error identification method, which comprises the following steps of: acquiring normal section two-dimensional original data of a raceway, fitting the original data through a sliding window to screen outer diameter section data, and completing clamping inclination error correction through least square fitting and coordinate transformation; in combination with a contourgraph hardware measurement parameter, continuously compensating a displacement coupling error to obtain new two-dimensional data; screening out raceway contour data from the new two-dimensional data, dividing the raceway contour data into segments containing complete left and right raceways, and fitting radiuses and circle centers of left and right arcs of each segment; preferentially adopting a geometric analysis method to solve the circle center of the ball for each segment, and switching a grid constraint centering algorithm to carry out iterative positioning in case of failure; and calculating a comparison design value of the contact angle and the nominal lead. Through a dual error correction mechanism and a dual-path circle center solving strategy, the problem of measurement errors caused by clamping inclination and displacement coupling of a contourgraph lever structure in the existing measurement technology is solved, and the measurement precision and the data processing efficiency are both considered.
Owner:XIAN UNIV OF TECH

Image navigation and precise positioning system for gynecological minimally invasive surgery

The invention relates to the technical field of medical equipment, in particular to a gynecological minimally invasive surgery image navigation and precise positioning system which comprises a navigation tracking module, an image reconstruction module, a medical image registration module, an identification module, a path planning module and a display module. Comprising a feature characterization unit, a topology analysis unit and a self-adaptive registration unit, and by extracting differential curvature features of an anatomical structure, constructing a multi-scale geometric analysis framework, calculating persistent coherence features, analyzing branch structure features and executing geodesic line optimization registration on a Riemannian manifold, a geodesic line is obtained. The navigation tracking module integrates electromagnetic positioning and optical positioning technologies and provides a dual verification mechanism, and the path planning module plans an optimal operation path based on an identification result, avoids the key anatomical structures, performs accurate registration on a preoperative CT / MRI image and an intraoperative real-time endoscope image, and performs accurate registration on the preoperative CT / MRI image and the intraoperative real-time endoscope image. And the registration precision reaches a submillimeter level.
Owner:GENERAL HOSPITAL OF THE NORTHERN WAR ZONE OF THE CHINESE PEOPLES LIBERATION ARMY

Three-dimensional tangent point-passing route planning method based on hierarchical projection and sliding window geometric analysis

The invention discloses a three-dimensional tangent point-passing route planning method based on hierarchical projection and sliding window geometric analysis. The method comprises the following steps: S1, unifying and initializing a coordinate system; s2, a three-element sliding window geometric solution algorithm is adopted to generate a two-dimensional optimal smooth path composed of straight line segments and arc segments; s3, converting the two-dimensional optimal smooth path to a three-dimensional geographic space; and S4, outputting the three-dimensional coordinate information of all the path points to an external visualization module. The method has the beneficial effects that a complicated three-dimensional problem is decomposed into low-dimensional two-dimensional geometric solution and height mapping by adopting a layering strategy of two-dimensional first and three-dimensional second, and a three-element sliding window is utilized to carry out iterative analysis on local elements, so that global large-scale optimization solution is avoided, the algorithm complexity is remarkably reduced, and the algorithm efficiency is improved. The planning process has high calculation efficiency, and the real-time or quasi-real-time route planning requirement can be met.
Owner:CHENGDU BOOSTOR TECH

A structural thermo-mechanical coupling method and apparatus considering isogeometric analysis

PendingCN122088067AImprove analysis efficiencyavoid approximation errorDesign optimisation/simulation3D modellingThermal forceStructural coupling
This invention discloses a structural thermo-mechanical coupling method and apparatus considering isogeometric analysis, belonging to the field of thermodynamics. The method includes: S1. Establishing an isogeometric NURBS model: providing the basis for expressing geometric and physical fields for thermo-mechanical coupling analysis, achieving seamless integration of CAD and CAE; S2. Calculating the transient temperature field based on the central difference method: obtaining the temperature distribution of the structure at different times, providing temperature input for subsequent thermo-mechanical coupling; S3. Transforming the temperature field into equivalent temperature loads: converting the thermal effects caused by temperature changes into equivalent loads identifiable by structural mechanics analysis; S4. Solving the stiffness equation of the structure under the combined action of external forces and temperature: obtaining the displacement matrix of the structural control points; S5. Solving the structural coupling field based on the displacement matrix: obtaining all key physical quantities in the thermo-mechanical coupling field, completing the coupling analysis. This invention can verify the feasibility of applying isogeometric analysis in coupled fields.
Owner:TIANJIN UNIV

Method, device and medium for analyzing static stability boundary of alternating current line based on phasor geometry

The application discloses an alternating current line static stability boundary analysis method and device based on a phasor geometry, and a medium, and relates to the technical field of alternating current line static stability. The method is based on a line impedance model of a reference system of a first-end voltage, and a voltage phasor triangle composed of the first-end voltage, a last-end voltage and a line voltage drop is constructed. By analyzing the trajectory of the vertex of the triangle moving along the corresponding circumcircle arc when the last-end complex power changes, a core relationship that the apparent power is proportional to the area of the triangle is found. It is proved that when the triangle is an isosceles triangle, the apparent power reaches the maximum value and is a line static stability critical point. Therefore, the application proposes that the isosceles of the voltage phasor triangle is used as a geometric condition for judging the static stability boundary, and power, voltage, power angle and impedance boundaries of the line static stability are derived. The application converts the traditional complex nonlinear algebraic problem into clear geometric analysis, the physical concept is clear, and the solving process is significantly simplified.
Owner:CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY

Gas ultrasonic gas flowmeter and measurement method thereof

The present application relates to the technical field of flow measurement and industrial process control, in particular to a kind of gas ultrasonic gas flowmeter and its measuring method;It contains measurement pipe section, signal acquisition, phase space reconstruction, symplectic geometry analysis and adaptive solution module;System through the acquisition original sound wave time sequence signal, mapping is high-dimensional state trajectory matrix;Its core is to use symplectic geometry transformation to extract maximum Lyapunov exponent and other dynamic invariants, determine flow field distribution correction coefficient, and compensate the basic flow rate to generate standard flow;The present application converts complex fluid mechanics inverse problem into geometric topology feature extraction problem, without mass model training, significantly reduces the operation power consumption and solves the computing deadlock problem.
Owner:NINGBO LIQING ULTRASONIC TECH CO LTD

Multi-arc-segment symmetric structural member measurement system, method and device and storage medium

The invention relates to a multi-arc-segment symmetric structural member measurement system, method and device and a storage medium. The system comprises an OCT image acquisition device, a contour extraction module, a curve analysis module and a circle fitting module, the OCT image acquisition device is used for acquiring an original tomographic image of a to-be-detected sample by utilizing an OCT imaging technology, and the contour extraction module is used for extracting surface contour features of the preprocessed image by adopting morphology and a connected region processing algorithm; the curve analysis module is used for performing curvature analysis and segmental arc identification on the surface contour features based on a differential geometry principle and a multi-scale analysis method, and the circle fitting module is used for performing geometric analysis on segmental arc segmentation results by combining algebraic fitting and geometric fitting algorithms, judging the opening direction of each segmental arc and generating circle fitting parameters. According to the invention, an end-to-end automatic measurement process is formed by using an integrated design, the operation cost and time consumption are reduced, and the measurement precision, efficiency and reliability are improved.
Owner:JIHUA LAB

A self-adaptive loop subdivision surface equal geometric analysis model establishment method

PendingCN122413500AAlgorithmThresholding
This invention discloses a method for establishing a geometric analysis model for NURBS surfaces using adaptive Loop subdivision, comprising the following steps: (1) setting curvature threshold parameters and a maximum number of samplings; (2) performing initial uniform sampling on the NURBS parameter domain; (3) calculating the curvature threshold and the average curvature of the point set based on the average curvature of the surface, identifying feature regions, and performing Delaunay triangulation on the current point set; (4) marking parameter points based on the curvature threshold, and inserting the marked parameter points into new parameter points based on the Delaunay triangulation relationship, with the new parameter points included in the point set; (5) repeating steps (3)-(4) until the maximum number of samplings is set, thereby capturing geometric details; (6) constructing a Delaunay triangulation on the latest point set; (7) applying Loop subdivision rules to generate a surface representation suitable for isogeometric analysis. The method of this invention is applicable to arbitrary topological structures, requires no multi-patch splicing, and provides a new solution for the accurate mechanical analysis of complex plate and shell structures.
Owner:GUANGXI UNIV

Three-dimensional modeling method for correlating coal permeability with pore and fracture evolution

The present application provides a kind of coal body permeability and pore fissure evolution associated three-dimensional modeling method, it is related to coal body structure three-dimensional modeling technical field, the present application is by to each time all voxel gray standardization, classification mark and space structure unit identification, combine voxel level parameter statistics and geometric analysis, can extract porosity, fracture width and fracture connectivity and other structure characteristic parameters, and with the physical field parameter dynamic pairing of synchronous acquisition, not only guarantee the physical accuracy and time sequence response ability of parameter, also realize the accurate assignment of voxel level parameter, so that coal body heterogeneity and dynamic evolution process can be carefully quantified, using voxel scale permeability calculation method, can calculate the permeability value of each voxel according to voxel characteristic parameters and physical field parameters at each time, generate the permeability distribution in three-dimensional space, can fully capture the structural evolution process of coal core sample.
Owner:INFORMATION RES INST OF EMERGENCY MANAGEMENT DEPT

A transfer orbit fast optimization method based on spatial conic splicing

The application discloses a transfer orbit fast optimization method based on spatial conic curve splicing, and belongs to the field of deep space exploration. The application expands the plane conic curve splicing method to the optimization of spatial earth-moon transfer orbit on the basis of the plane conic curve splicing method used for orbit transfer, by using coordinate conversion and geometric analysis method to increase the azimuth angle parameters theta and psi used for describing the spatial orientation of the earth-centered launch orbit plane; the application can improve the orbit analysis and optimization efficiency by using the two-body orbit theory to deduce the two-body model and based on the double two-body model splicing with analytical characteristics; the application can realize the fast optimization and solution of the transfer orbit based on the spatial conic curve splicing by establishing the penalty function iterative optimization of four independent optimization quantities, i.e., the earth-moon transfer launch speed increment, the moon influence ball entry point phase, the azimuth angle parameters theta and psi, according to the orbit inclination and the perigee height constraints. The application has the advantages of good convergence, high optimization efficiency and wide application range. The application is suitable for various earth-moon transfer missions and moon flyby orbit optimization.
Owner:BEIJING INST OF TECH

Electric charge notice structuring method combining geometric analysis and multi-level verification

The invention discloses an electric charge notice structuring method combining geometric analysis and multi-level verification, and relates to the technical field of document information processing.The method comprises the steps that firstly, an electric charge notice document is analyzed, and the text and geometric coordinates of the text are extracted; intelligently inferring a logic layout structure of the document through spatial clustering and alignment analysis based on the coordinates; extracting information based on the structural model to form structured data; verifying the data by using a multi-level rule engine; and when verification fails and a layout understanding error is identified, triggering a geometric model correction process, rechecking a coordinate relationship, optimizing a structure model, and performing iterative execution until data passes verification. According to the method, accurate geometric attributes of the electronic document are fully utilized, and layout analysis self-optimization is driven through business verification feedback; and high-precision and high-reliability structured information extraction of the searchable electric charge notice is realized.
Owner:SINOPEC SALES CO LTD GUANGDONG PETROLEUM BRANCH +1

Alternating current line static stability boundary analysis method and device based on phasor geometry and medium

The invention discloses an AC line static stability boundary analysis method and device based on phasor geometry and a medium, and relates to the technical field of AC line static stability. The method comprises the following steps: constructing a voltage phasor triangle formed by head end voltage, tail end voltage and line voltage drop based on a line impedance model of a head end voltage reference system; the core relation that the apparent power is in direct proportion to the area of the triangle is found by analyzing the moving track of the vertex of the triangle along the arc of the corresponding circumcircle when the complex power at the tail end changes. Therefore, when the triangle is an isosceles triangle, the apparent power reaches the maximum value and is a line static stability critical point. Therefore, according to the method, the voltage phasor triangular isosceles is used as a geometric condition for judging the static stability boundary, and the static stability power, voltage, power angle and impedance boundary of the line are deduced. According to the method, a traditional complex nonlinear algebraic problem is converted into clear geometric analysis, the physical concept is clear, and the solving process is remarkably simplified.
Owner:CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY