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34 results about "Analysis of covariance" patented technology

Analysis of covariance (ANCOVA) is a general linear model which blends ANOVA and regression. ANCOVA evaluates whether the means of a dependent variable (DV) are equal across levels of a categorical independent variable (IV) often called a treatment, while statistically controlling for the effects of other continuous variables that are not of primary interest, known as covariates (CV) or nuisance variables.

Local curved surface change factor based scattered point cloud data compaction processing method

InactiveCN104616349AImprove search efficiencyOvercoming the results of reduced efficiencyImage generation3D modellingFactor basePoint cloud
The invention discloses a local curved surface change factor based scattered point cloud data compaction processing method. The local curved surface change factor based scattered point cloud data compaction processing method comprises the steps of 1 reading measured point cloud data, 2 calculating a central point of a point cloud, 3 searching dynamic K neighborhood points of the central point based on cubic grids and accordingly establishing the topological relation of scattered point cloud, 4 adopting a variance component method to calculate curved surface change factors of a k neighborhood of the central point, 5 determining the compaction rate of each cubic grid in the k neighborhood of the central point and performing even compaction in within a k neighborhood range. The topological relation of the scattered point cloud is established by establishing the dynamic K neighborhood point information of the scattered point cloud. Complicated curvature calculation is replaced by the curved surface change factors. The compaction ratio is adjusted according to the curved surface change factors Xi, even compaction within the k neighborhood range is achieved, the detail characteristic of high curvature can be protected, and planar characteristic of low curvature is also protected when the compaction degree is high. Point cloud data processing and curved surface reconstruction efficiency and accuracy are improved.
Owner:TIANJIN UNIV

Satellite non-linear relative movement deviation propagation analysis method

The invention discloses a satellite non-linear relative movement deviation propagation analysis method. The method comprises steps that a main satellite and a secondary satellite are assigned, a reference satellite absolute track state at the initial time, a two-satellite nominal relative movement state and a probability density function of initial relative movement state deviation are inputted, first-order and second-order state transfer tensors used for analyzing and forecasting a satellite relative movement state and deviation are calculated according to a non-linear relative movement equation considering J2 perturbation, a covariance analysis method is utilized for Gauss distribution, an analytic result is further outputted, otherwise, Gauss and model calculation is utilized, and an analytic result is outputted. A J2 perturbation item and a second-order non-linear item are considered, the method can be utilized for long-time high-precision analysis forecast of relative movement state deviation of two distant satellites, the acquired deviation information can be used for formation satellite bump probability calculation and bump early warning, and the method further has properties of accurate and reasonable design, small method analysis computational complexity and good applicability to actual engineering tasks.
Owner:NAT UNIV OF DEFENSE TECH

Point cloud simplification method based on survival probability

The invention discloses a point cloud simplification method based on survival probability, and the method comprises: reading original point cloud data, building a topological relation for the originalpoint cloud data based on a kdtree algorithm, and obtaining all neighborhood points in a radius r range of each data point; performing covariance analysis on each data point and neighborhood points thereof by using multi-thread parallel computing based on a principal component analysis method to obtain a covariance matrix; dividing all the data points into boundary points or non-boundary points according to whether the data points are the boundary points or not, sorting the non-boundary points according to curvature, and dividing the non-boundary points into high-curvature points and low-curvature points according to a preset threshold value; calculating the number of points needing to be deleted from the boundary point, the high curvature point and the low curvature point according to the preset simplification ratio and the sizes of n1, n2 and n3; and traversing each data point of the point cloud based on multi-thread parallel computing, randomly generating a random number with the size between 0 and 1 each time, and comparing the random number with the survival probability to obtain simplified point cloud data.
Owner:XI AN JIAOTONG UNIV

Brain interval covariance analysis method for functional magnetic resonance data processing

InactiveCN103838943AStrong correlationResponse interdependenceImage analysisSpecial data processing applicationsBrain mappingCovariance
The invention discloses a brain interval covariance analysis method for functional magnetic resonance data processing. The method includes the following steps that preprocessing is carried out, wherein individual differences are eliminated firstly to obtain statistical parameter images; then regions of interest are designated according to the images; registration and standardization are carried out on brain mappings by means of an SPM software package; according to experimental design, an estimation model is appointed, so that a statistical result is obtained; according to distributed situations of activated brain intervals, precise anatomic sites of the activated regions are found out, and the regions of interest are designated; effective connection analysis based on the regions of interest is carried out, wherein a function regulation model of a correlation analysis of a brain loop is established through correlation analysis of signal values. Specifically, the relation among the regions of interest is found out through comparison changes, relative to control, of tasks of different regions of interest. Interdependency among the brain intervals can be dynamically reflected in the process of performing the tasks through time covariance analysis and time dependence connection dynamic analysis.
Owner:DALIAN LINGDONG TECH DEV

An analytical method for analyzing satellite nonlinear relative motion bias propagation

The invention discloses a satellite non-linear relative movement deviation propagation analysis method. The method comprises steps that a main satellite and a secondary satellite are assigned, a reference satellite absolute track state at the initial time, a two-satellite nominal relative movement state and a probability density function of initial relative movement state deviation are inputted, first-order and second-order state transfer tensors used for analyzing and forecasting a satellite relative movement state and deviation are calculated according to a non-linear relative movement equation considering J2 perturbation, a covariance analysis method is utilized for Gauss distribution, an analytic result is further outputted, otherwise, Gauss and model calculation is utilized, and an analytic result is outputted. A J2 perturbation item and a second-order non-linear item are considered, the method can be utilized for long-time high-precision analysis forecast of relative movement state deviation of two distant satellites, the acquired deviation information can be used for formation satellite bump probability calculation and bump early warning, and the method further has properties of accurate and reasonable design, small method analysis computational complexity and good applicability to actual engineering tasks.
Owner:NAT UNIV OF DEFENSE TECH

Scattered Point Cloud Data Reduction Method Based on Local Surface Variation Factor

InactiveCN104616349BImprove search efficiencyOvercoming the results of reduced efficiencyImage generation3D modellingPoint cloudFactor XI
The invention discloses a local curved surface change factor based scattered point cloud data compaction processing method. The local curved surface change factor based scattered point cloud data compaction processing method comprises the steps of 1 reading measured point cloud data, 2 calculating a central point of a point cloud, 3 searching dynamic K neighborhood points of the central point based on cubic grids and accordingly establishing the topological relation of scattered point cloud, 4 adopting a variance component method to calculate curved surface change factors of a k neighborhood of the central point, 5 determining the compaction rate of each cubic grid in the k neighborhood of the central point and performing even compaction in within a k neighborhood range. The topological relation of the scattered point cloud is established by establishing the dynamic K neighborhood point information of the scattered point cloud. Complicated curvature calculation is replaced by the curved surface change factors. The compaction ratio is adjusted according to the curved surface change factors Xi, even compaction within the k neighborhood range is achieved, the detail characteristic of high curvature can be protected, and planar characteristic of low curvature is also protected when the compaction degree is high. Point cloud data processing and curved surface reconstruction efficiency and accuracy are improved.
Owner:TIANJIN UNIV

A Point Cloud Reduction Method Based on Survival Probability

The invention discloses a point cloud simplification method based on survival probability. In the method, the original point cloud data is read, the topological relationship is established for the original point cloud data based on the kdtree algorithm, and the radius r range of each data point is obtained. All the neighborhood points within; Based on the principal component analysis method, multi-threaded parallel computing is used to perform covariance analysis on each data point and its neighborhood points to obtain a covariance matrix; all data points are divided into boundary points or boundary points according to whether they are boundary points or Non-boundary points, sort the non-boundary points according to the curvature, and divide them into high curvature points and low curvature points according to the predetermined threshold; according to the predetermined simplification ratio and n 1 , n 2 , n 3 The size of the calculation of boundary points, high curvature points and low curvature points need to delete the number of points; based on multi-threaded parallel computing to traverse each data point of the point cloud, each time a random number between 0 and 1 is randomly generated , comparing the random number with the survival probability to obtain the simplified point cloud data.
Owner:XI AN JIAOTONG UNIV
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