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71 results about "Covariate" patented technology

In statistics, a covariate is a variable that is possibly predictive of the outcome under study. A covariate may be of direct interest or it may be a confounding or interacting variable. The alternative terms explanatory variable, independent variable, or predictor, are used in a regression analysis. In econometrics, the term "control variable" is usually used instead of "covariate". In a more specific usage, a covariate is a secondary variable that can affect the relationship between the dependent variable and other independent variables of primary interest. An example is provided by the analysis of trend in sea-level by Woodworth. Here the dependent variable was the annual mean sea level at a given location for which a series of yearly values were available. The primary independent variable was "time". Use was made of a "covariate" consisting of yearly values of annual mean atmospheric pressure at sea level. The results showed that inclusion of the covariate allowed improved estimates of the trend against time to be obtained, compared to analyses which omitted the covariate.

Modeling loss in a term structured financial portfolio

InactiveUS20060195391A1Increase flexibilityIncreases empiricismFinanceRisk profilingHorizon
In accordance with the principles of the present invention, an apparatus, simulation method, and system for modeling loss in a term structured financial portfolio are provided. An historical date range, time unit specification, maturity duration, evaluation horizon, random effects specification, and set of portfolio covariates are selected. Historical data is then segmented into infinitely many cumulative loss curves according to a selected covariate predictive of risk. The s-shaped curves are modeled according to a nonlinear kernel. Nonlinear kernel parameters are regressed against time units up to the maturity duration and against selected portfolio covariates. The final regression equations represent the central moment models necessary for prior distribution specification in the hierarchical Bayes model to follow. Once the hierarchical Bayes model is executed, the finite samples generated by a Metropolis-Hastings within Gibbs sampling routine enable the inference of net dollar loss estimation and corresponding variance. In turn, the posterior distributions enable the risk analysis corresponding to lifetime loss estimates for routine risk management, the valuation of derivative financial instruments, risk-based pricing for secondary markets or new debt obligations, optimal holdings, and regulatory capital requirements. Posterior distributions and analytical results are dynamically processed and shared with other computers in a global network configuration.
Owner:STANELLE EVAN J

Automated generator of optimal models for the statistical analysis of data

Provided is an automated process for producing accurate statistical models from sample data tables. The process solves for the optimal parameters of each statistical model considered, computes test statistics and degrees of freedom in the model, and uses these test statistics and degrees of freedom to establish a complete ordering of the statistical models. In cases where the sample data table is sufficiently small, the process constructs and analyzes all reasonable statistical models that might fit the data table provided. In cases where the number of possible models is prohibitively high, the process begins by constructing and solving more general models and then constructs and solves those more detailed models that are similar to those general models that achieved the highest ordering. In either of these two cases, the process arrives at a statistical model that is highest in the ordering and is thus deemed most suitable to model the sample data table. The result of this process is a statistical model deemed to be most suitable to model the sample data table and a set of average table values produced by this resulting model. This resulting table may include modeled values for table entries for which no initial data was supplied. This invention finds application in the area of credit scoring, where covariates such as age, profession, gender, and credit history are used to determine the likelihood that an individual will default on a loan. It also finds application in analyzing the effectiveness of many types of tools as they are used in various environments (e.g., the effectiveness of radar when used in different weather conditions). It also finds application in the area of insurance, where one wishes to estimate the future number of claims against a specific insurance policy based on a database of past insurance claims.
Owner:DANIEL H WAGNER ASSOCS

Covariant initial value determination method for optimal landing track design

ActiveCN108196449ASolve the defects that are not easy to solveSmall amount of calculationAdaptive controlDeep space explorationOptimal control
The invention discloses a covariant initial value determination method for the optimal landing track design and belongs to the field of deep space exploration. The covariant initial value determination method includes building a small body fixing coordinate system and corresponding detector landing kinetic equations; converting the optimal design problem of the small body landing track into the optimal control problem and the corresponding two-point boundary value problem, and defining the problems as the problem 1; approximating the problem 1, and defining the approximated problem 1 as the problem 2; solving the covariant initial values lambda<r2(t0)> and lambda<v2(t0)> of the problem 2, setting the the covariant initial values lambda<r2(t0)> and lambda<v2(t0)> of the problem 2 as iterative initial values of the covariant initial values lambda<r1(t0)> and lambda<v1(t0)> of the problem 1, determining the iterative initial value of the covariant initial value lambda<m1(t0)> of the problem 1 according to the setting of the iterative initial values, namely lambda<r2(t0)> and lambda<v2(t0)>, of the covariant initial values lambda<r1(t0)> and lambda<v1(t0)> of the problem 1, thereby achieving the iterative initial value setting of the covariant initial values for the optima landing track design. The defect that it is difficult to solve the two-point boundary value problem due to improper initial value setting can be avoided by application of the method.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

Failure rate calculation method for relay protection device in consideration of covariates

A failure rate calculation method for a relay protection device in consideration of covariates belongs to the technical field of protection of electric power systems. The method comprises the following steps of: determining the function relationship between relay protection failure rate distribution parameters and the covariates by using a multiplication model; obtaining failure rate distribution functions under the Weibull distribution condition by the function relationship between the parameters and the covariates; and obtaining unknown parameters of the distribution functions through the formula (referring to the Specification) in order to calculate the failure rate of the relay protection device, wherein m and Eta in the formula respectively represent Weibull distribution shape parameters and scale parameters. According to the failure rate calculation method for the relay protection device in consideration of the covariates disclosed by the invention, the failure characteristics of the relay protection device are accurately simulated in consideration of the intrinsic characteristics of the relay protection and the external working conditions thereof, so that the covariates and failure rate calculation method for the relay protection is built. And the method is helpful to find out the principal factors which influence the reliability indexes of the method, and provides the guidance to improve the relay protection reliability.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)

Electric spindle service life evaluation method without sudden failure information

ActiveCN109522650AImprove accuracyImprove reliability modeling accuracyGeometric CADDesign optimisation/simulationElectricityFailure rate
The invention belongs to the technical field of reliability analysis of electric spindles, and relates to an electric spindle service life evaluation method without sudden failure information. The defect that sudden failure and the influence of degradation on the sudden failure are ignored when modeling is conducted according to degradation information in the prior art is overcome. The method comprises the following steps that 1, an electric spindle product timing truncation reliability test and electric spindle product degradation information collection are conducted; 2, index distribution product reliability modeling; 3, reliability modeling of Weibull distribution products; 4, carrying out partial distribution competition risk reliability modeling under the condition of no burst failureinformation in combination with the degradation information; And 5, evaluating the service life of the motorized spindle based on the partial distribution competition risk reliability model. The partial distribution competition risk modeling method based on the unilateral confidence limit modeling basic failure rate and with the multi-performance degradation amount as the covariable is provided from the perspective of competition failure, and the method has important significance for reasonably evaluating the reliability level of the electric spindle and perfecting the reliability technical system of the electric spindle.
Owner:JILIN UNIV

Air pollution prediction method based on deep fusion of multi-source space-time big data

The invention discloses an air pollution prediction method based on deep fusion of multi-source space-time big data. The method comprises the following steps: collecting and preprocessing multi-source big data; inverting the meteorological data to obtain high-resolution ground meteorological parameters; carrying out missing inversion and upscaling on aerosol parameters and NO2 remote sensing parameters; traffic variables, land utilization variables, social economy and POI variables and spatial-temporal variation variables are extracted; carrying out space-time fusion on covariable data of various kinds of space-time big data to form a data set with unified scale and space coordinates; inverting high-resolution earth surface parameters of the air pollution concentration; verifying and evaluating the precision; if the standard is reached, outputting a result; and if not, adjusting and circularly training until a reasonable model and prediction are obtained. According to the method, the space-time coverage is large, grid modeling of meteorological data and interpolation of satellite parameters are improved through an advanced optimization technology, high test precision and high generalization are achieved, estimation deviation is reduced through a result verification and circulating modeling mechanism, and the efficiency of practical application is improved.
Owner:INST OF GEOGRAPHICAL SCI & NATURAL RESOURCE RES CAS

Slice priority prediction system for H.264 video

The invention relates to systems and methods for prioritizing video slices of H.264 video bitstream comprising: a memory storage and a processing unit coupled to the memory storage, wherein the processing unit operates to execute a low complexity scheme to predict the expected cumulative mean squared error (CMSE) contributed by the loss of a slice of H.264 video bitstream, wherein the processing unit operates to execute a series of actions comprising assigning each slice a predicted value according to the low complexity scheme; extracting video parameters during encoding process, said video parameters; and using a generalized linear model to model CMSE as a linear combination of the video parameters, wherein the video parameters are derived from analytical estimations by using a Generalized Linear Model (GLM) over a video database, encompassing videos of different characteristics such as high and low motion, camera panning, zooming and still videos, further comprising wherein the GLM is constructed in a training phase as follows: determining the distribution of the computed CMSE to be a Normal distribution with the Identity link function; sequentially adding covariates using the forward selection technique where by the best model is evaluated at each stage using the Akaike's Information Criterion (AIC); the training phase of the model generates regression coefficients; the final model is validated through the testing phase by predicting the CMSE for different video sequences, not in the training database; and by using the regression coefficients, the expected CMSE values are predicted for each slice.
Owner:SAN DIEGO STATE UNIV RES FOUND

Gas compressor rotation stall early warning method based on time expansion convolutional network

ActiveCN113569338AImprove the performance of active controlImprove forecast accuracyGeometric CADSustainable transportationData setGas compressor
A gas compressor rotation stall early warning method based on a time expansion convolutional network comprises the following steps: firstly, preprocessing dynamic pressure data of an aero-engine, and dividing a test data set and a training data set from experimental data; secondly, sequentially constructing a time convolutional network module, constructing a Resnet-v network module, constructing a time expansion convolutional network prediction model, and storing an optimal prediction model; finally, performing real-time prediction on the test data: firstly, adjusting the data dimension of the test set according to the input requirement of the time convolutional network prediction model; according to a time sequence, calculating a surge prediction probability of each sample through a time expansion convolutional network prediction model; and calculating the real-time surge probability of a pair of samples containing covariables and not containing covariables through a time expansion convolutional network prediction model, and observing the improvement effect of the covariables on the model prediction effect. The time domain statistical characteristics and the change trend are integrated, and the prediction precision is improved; and the active control performance of the engine can be improved, and certain universality is achieved.
Owner:DALIAN UNIV OF TECH

enterprise risk trust loss model based on Cox regression prediction

InactiveCN109657976AAnticipate the risk of dishonestyResourcesStart timeSurvival probability
The invention discloses an enterprise risk trust loss model based on Cox regression prediction. the lost credit survival probability of the lost credit model is calculated; f (D), using an enterprisecredit model feature Y as a covariable or an interaction item; The construction method of the lost credit model comprises the following steps of: constructing a lost credit model; Q1, determining a feature Y of the lost credit model, Q2: formulating a lost credit model observation starting time D1; Q3: formulating a lost credit observation time D3; Q4: formulating a lost credit end point time D2 or D3; Q5, formulating a lost credit survival time D; Q6, determining a reference risk function f0 (D) of the lost trust model; Q7, determining a partial regression coefficient of the characteristic Yof the lost trust model through likelihood estimation; Q8, brining The survival time D, the untrustworthy model feature Y, the untrustworthy model reference risk function f0(D), and the partial regression coefficient Beta of the untrustworthy model feature Y into the unbalanced risk function formula of the Cox proportional regression model. According to the model disclosed by the invention, the future risk change trend of an enterprise can be predicted, so that the possibility of enterprise credit risk occurrence can be predicted. The model disclosed by the invention has the advantages that the risk change trend of the enterprise can be predicted.
Owner:重庆誉存科技有限公司

Multi-output gradient lifting tree modeling method for survival risk analysis

ActiveCN110119540AImprove accuracySolve the problem of insufficient explanationForecastingDesign optimisation/simulationRisk profilingSurvival analysis
The invention provides a multi-output gradient lifting tree modeling method for survival risk analysis, which comprises the following steps: firstly, constructing an expression of survival data for establishing a survival prediction model of financial, insurance, medical, traffic or industrial target industries under a model algorithm framework of an optimal gradient lifting tree (XGBoost); then defining and calculating a loss function corresponding to the survival data; then, defining and calculating a first step degree and a second step degree corresponding to the loss function; and finally,inputting the calculated loss function value and the first-order gradient value and the second-order gradient value of the loss function into an XGBoos model algorithm framework at the same time, andperforming automatic training to generate a survival prediction model of the target industry. The modeling method provided by the invention can better represent the relationship between the model covariable and the risk prediction value. The prediction performance and the generalization capability of the model are improved. The prediction performance and the risk distinguishing degree are better,and the application scene is wide.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
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