31 results about "Domain decomposition methods" patented technology

The present invention relates to an iris identification method and system, which divide an iris image, which is acquired for personal identification, into a plurality of equal / unequal and multiscale regions, generate a corresponding code corresponding to the respective regions, organizing codes into a database, generate a code at the time of authentication in the same manner, and identify a person by comparing this code with the codes stored in the database, thus improving identification speed and rate.The present invention provides an iris identification method including iris code registration and iris code authentication, the iris code registration including the steps of acquiring iris images by capturing iris using cameras or receiving image files, generating iris codes from the acquired iris images, and storing the generated iris codes in a database, the iris code authentication including the steps of acquiring an iris image in a manner identical to that of the iris code registration, generating an iris code from the acquired iris image, and identifying the generated iris code by comparing the generated iris code with the iris codes stored in the database, wherein the iris code generation step is performed in such a way as to determine the inner and outer boundaries of an iris region by approximating the inner and outer boundaries with general curves based on actual shapes of the inner and outer boundaries, divide a part or all of a region between the inner and outer boundaries into one or more unit sectors, and generate an iris code corresponding to the respective sectors, and the iris code identification step is performed in such a way as to measure the distances of the generated code to the existing codes stored in the database and determine whether each of the distances falls within a threshold value.

In a method for domain decomposition for generating unstructured grids, a surface mesh is generated for a spatial domain. A location of a partition plane dividing the domain into two sections is determined. Triangular faces on the surface mesh that intersect the partition plane are identified. A partition grid of tetrahedral cells, dividing the domain into two sub-domains, is generated using a marching process in which a front comprises only faces of new cells which intersect the partition plane. The partition grid is generated until no active faces remain on the front. Triangular faces on each side of the partition plane are collected into two separate subsets. Each subset of triangular faces is renumbered locally and a local / global mapping is created for each sub-domain. A volume grid is generated for each sub-domain. The partition grid and volume grids are then merged using the local-global mapping.

The invention discloses an X ray multi-energy-spectrum CT (Computed Tomography) finite angle scanning and image iterative reconstruction method, which comprises the following steps that: applying theX rays of a plurality of energy spectrums to scan an object in a respective finite angel range, and obtaining the projection data of a tested object under each energy spectrum; on the basis of the projection data, independently reconstructing the image of each tested object under each energy spectrum; utilizing the consistency of the tested object and the complementarity of the reconstructed imageunder each energy spectrum, designing a combined regularization method to effectively remove an artifact caused by finite angle scanning in the reconstructed image under each energy spectrum, and calculating to obtain a high-quality reconstructed image; and therefore, applying an image domain decomposition method or a projection domain decomposition method to calculate to obtain the base materialimage or the dual-effect image of the tested object. The method is suitable for the image reconstruction of the multi-energy-spectrum CT under a finite angle scanning condition, the dosage of the X ray is lowered, scanning time is shortened, and the method has the advantages of high reconstructed image quality, high rate of convergence and the like.

In a method for domain decomposition for generating unstructured grids, a surface mesh is generated for a spatial domain. A location of a partition plane dividing the domain into two sections is determined. Triangular faces on the surface mesh that intersect the partition plane are identified. A partition grid of tetrahedral cells, dividing the domain into two sub-domains, is generated using a marching process in which a front comprises only faces of new cells which intersect the partition plane. The partition grid is generated until no active faces remain on the front. Triangular faces on each side of the partition plane are collected into two separate subsets. Each subset of triangular faces is renumbered locally and a local / global mapping is created for each sub-domain. A volume grid is generated for each sub-domain. The partition grid and volume grids are then merged using the local-global mapping.

The invention discloses an analysis method for pumped storage generator damper winding magnetic field characteristics, and belongs to the technical field of pumped storage generator magnetic field analysis. In order to solve the problem that an effective method capable of accurately analyzing a specific relationship between the pumped storage generator magnetic field and a damper winding does not exist at present, the method comprises the following steps that: S1: establishing a mathematical model and a finite element model, and finishing simulation; S2: simplifying a physical model; S3: determining the mathematical model; S4: calculating electromagnetic force borne by damping bars, exciting windings, pole bodies and pole shoes in different working condition conversion and transition processes; S5: coupling a domain decomposition method with a radial basis element-free method; S6: obtaining a function relationship between a loading rate and a damper winding dynamic conversion current; and S7: analyzing a result. By use of the analysis method for pumped storage generator damper winding magnetic field characteristics, dependency on elements can be gotten rid of, and the method has the advantages of high accuracy, simpleness in calculation and the like.

Disclosed are techniques for simulating and correcting the mask shadowing effect using the domain decomposition method (DDM). According to various implementations of the invention, DDM signals for an extreme ultraviolet (EUV) lithography mask are determined for a plurality of azimuthal angles of illumination. Base on the DDM signals, one or more layout designs for making the mask may be analyzed and / or modified.

The invention relates generally to a method for the calculation of radiation field distributions employing a new parallel 3-D radiation transport code and, a multi-processor computer architecture. The code solves algorithms using a domain decomposition approach. For example, angular and spatial domains can be partitioned into subsets and, the subsets can be independently allocated and processed.

Systems and methods for optimizing processor requirements for a complex hardware system are disclosed. A set of complex hardware system configuration constraints are formulated as an objective function and a set of linear inequalities, and a convex polytope is formed from the set of linear inequalities. The objective function is optimized over the convex polytope using mixed integer linear programming means to obtain an optimal solution. Processor requirements for the complex hardware system are determined based on the optimal solution.

The invention discloses a domain decomposition finite element method for simulating Darcy speed at an underground medium interface. The method comprises the following steps: performing variation on anunderground flow problem by using a Galerkin method, sub-dividing a research domain, and acquiring waterhead by applying the finite element method; decomposing the research domain into a plurality ofsingle-medium sub-domains by applying interfaces of different mediums according to the medium composition of the research domain, and decomposing an underground Darcy speed solution problem on the research domain into sub-problems on the sub-domain by applying the domain decomposition method; selecting one sub-problem, performing variation by using the Galerkin method, and acquiring the Darcy speed by applying a Galerkin model of the Yeh, acquiring the Darcy speed at the other side of the interface of the sub-domain and other sub-domain by combining with the refraction law as the first classof boundary condition of the adjacent sub-problem; selecting the next sub-problem to solve, and repeating this process until all sub-problems are completely solved. By using the method disclosed by the invention, the computing consumption of the Darcy speed is reduced through the domain decomposition method, and the precision of the Darcy speed at the interface is guaranteed by using the refraction law.

The invention discloses a dual-domain decomposition method for enhancing noise-containing images in underground mines. The method first uses a Gaussian filter in space to decompose the noise-containing images in underground mines in layers to realize the decoupling of image contrast improvement and noise suppression; The maximum bright channel image of the base layer obtained by the layer is used as the illuminance component estimation of the Retinex model. According to the Retinex enhancement principle, the contrast of the base layer is improved; The shearlet transform domain implements hard threshold shrinkage on the decomposition coefficients to achieve noise suppression in the detail layer. The non-subsampled shearlet inverse transform shrinks the decomposition coefficients to obtain the noise suppression detail layer. Using the same enhancement ratio as the base layer, the noise suppression detail layer is achieved. Enhancement; finally, the fusion enhanced image is obtained by fusing the enhanced base layer and the noise-suppressed enhanced detail layer, and Gamma fine-tuning is performed on the fusion-enhanced image to obtain the final noise-suppressed and contrast-enhanced enhanced image.

The present invention discloses a domain decomposition parallel method effective for an unconditional stable time-domain finite difference method. In the present invention, the causal domain decomposition method is used to realize the height parallelization of the frog jump alternating direction implicit scheme time-domain finite difference method, and height parallel calculation can be carried out while the unconditional stability is maintained. According to the method disclosed by the present invention, the simulating calculation time on the time-domain finite difference method can be effectively saved, and the programming is simple and the method has a strong practical engineering application value.

A chip thermal analysis method based on three-dimensional domain decomposition comprises the steps of adopting a non-overlapping domain decomposition method to perform thermal analysis of a chip system including a chip and a heat-radiating part, performing discrete grid division of different domains of the chip system respectively, setting an appropriate condition at each domain interface position to solve the domains and achieving convergence of a computed result of the interface position of the chip and the heat-radiating part through multiple overall iterations. By means of the chip thermal analysis method based on the three-dimensional domain decomposition, temperature distribution of the chip in the chip system can be quickly calculated.

The invention relates generally to a method for the calculation of radiation field distributions employing a new parallel 3-D radiation transport code and, a multi-processor computer architecture. The code solves algorithms using a domain decomposition approach. For example, angular and spatial domains can be partitioned into subsets and, the subsets can be independently allocated and processed.

The invention provides a fast calculation method for solving hyperbolic conservation law equations and Euler equations based on domain decomposition coupled high-precision DG and WENO methods. The method first performs domain decomposition on the original problem, that is, adopts a structure in the area near the physical boundary Or the unstructured discontinuous finite element method (DG), using the finite body difference weighted intrinsically non-oscillating (WENO) scheme under the structured mesh in the remaining regular regions. In the process of dealing with the domain coupling interface, there are two processing methods, one is the conservative coupling processing method; the other is the non-conservative coupling processing method. In the actual calculation process, we use the bad element indicator to judge whether the solution near the interface is sufficiently smooth. If the solution is sufficiently smooth, the non-conservative coupling method is used at the interface, otherwise, the conservative coupling method is used.