Dependent competing risks model is a practical model in the analysis of lifetime and failure modes.The dependence can be captured using a statistical tool to explore the re-lationship among failure causes.In this pape...Dependent competing risks model is a practical model in the analysis of lifetime and failure modes.The dependence can be captured using a statistical tool to explore the re-lationship among failure causes.In this paper,an Archimedean copula is chosen to describe the dependence in a constant-stress accelerated life test.We study the Archimedean copula based dependent competing risks model using parametric and nonparametric methods.The parametric likelihood inference is presented by deriving the general expression of likelihood function based on assumed survival Archimedean copula associated with the model parameter estimation.Combining the nonparametric estimation with progressive censoring and the non-parametric copula estimation,we introduce a nonparametric reliability estimation method given competing risks data.A simulation study and a real data analysis are conducted to show the performance of the estimation methods.展开更多
In this paper, a method of stabilizing electric power by a system which is a combination of wind power generation and pumped storage power generation is proposed. The system operates based on the output predicted valu...In this paper, a method of stabilizing electric power by a system which is a combination of wind power generation and pumped storage power generation is proposed. The system operates based on the output predicted value of the windfarm. When the measured windfarm output is larger than the predicted value, the system is pumping up water with surplus power. When the windfarm output is smaller than the predicted value, the system is filling up lack power by hydro generator. Also, since hydro generator works with a start-up delay time, output shortage occurs at this time. To improve output shortage at the time, we estimate the time below the predicted value by a statistical model. As the result, the system succeeded in stabilizing the power and improving the start-up delay time of the hydro generator.展开更多
The development of mathematical models of structurally inhomogeneous media leads to the necessity to consider structure of space itself where deformation occurs, i.e. change of mathematical apparatus itself. The space...The development of mathematical models of structurally inhomogeneous media leads to the necessity to consider structure of space itself where deformation occurs, i.e. change of mathematical apparatus itself. The space, whose coordinate axes are non-Archimedean straight lines, has been considered. Refusing the fulfillment of Archimedes’s law allows to describe multi-scaling of the space, and so to consider deformation processes on different scale levels. The construction of two-scale mathematical model of rock masses has been considered as an example. The constitutive equations have been formulated on micro-and macro-levels and interaction condition between different levels as well. On micro-level, the elastic behavior of grains and plastic sliding between grains with possible softening are taken into account. On macro-level, the model represents a nonlinear system of equations describing the anisotropic rock mass behavior. On the basis of model, the numerical algorithm and code have been carried out to solve the plane boundary value problems. Examples of numerical simulations of stress-strain state of structural rock masses nearby a tunnel opening are presented. The deformation contours and isolines of stresses are plotted.展开更多
基金Supported by the National Natural Science Foundation of China(12101476,12061091,11901134)the Fundamental Research Funds for the Central Universities(ZYTS23054,QTZX22054)+1 种基金the Yunnan Funda-mental Research Projects(202101AT070103)the Natural Science Basic Research Program of Shaanxi Province(2020JQ-285).
文摘Dependent competing risks model is a practical model in the analysis of lifetime and failure modes.The dependence can be captured using a statistical tool to explore the re-lationship among failure causes.In this paper,an Archimedean copula is chosen to describe the dependence in a constant-stress accelerated life test.We study the Archimedean copula based dependent competing risks model using parametric and nonparametric methods.The parametric likelihood inference is presented by deriving the general expression of likelihood function based on assumed survival Archimedean copula associated with the model parameter estimation.Combining the nonparametric estimation with progressive censoring and the non-parametric copula estimation,we introduce a nonparametric reliability estimation method given competing risks data.A simulation study and a real data analysis are conducted to show the performance of the estimation methods.
文摘In this paper, a method of stabilizing electric power by a system which is a combination of wind power generation and pumped storage power generation is proposed. The system operates based on the output predicted value of the windfarm. When the measured windfarm output is larger than the predicted value, the system is pumping up water with surplus power. When the windfarm output is smaller than the predicted value, the system is filling up lack power by hydro generator. Also, since hydro generator works with a start-up delay time, output shortage occurs at this time. To improve output shortage at the time, we estimate the time below the predicted value by a statistical model. As the result, the system succeeded in stabilizing the power and improving the start-up delay time of the hydro generator.
基金Supported by the Russian Foundation for Basic Research (10-05-91002)the Integration Project of the Siberian Branch,Russian Academy of Sciences (69)
文摘The development of mathematical models of structurally inhomogeneous media leads to the necessity to consider structure of space itself where deformation occurs, i.e. change of mathematical apparatus itself. The space, whose coordinate axes are non-Archimedean straight lines, has been considered. Refusing the fulfillment of Archimedes’s law allows to describe multi-scaling of the space, and so to consider deformation processes on different scale levels. The construction of two-scale mathematical model of rock masses has been considered as an example. The constitutive equations have been formulated on micro-and macro-levels and interaction condition between different levels as well. On micro-level, the elastic behavior of grains and plastic sliding between grains with possible softening are taken into account. On macro-level, the model represents a nonlinear system of equations describing the anisotropic rock mass behavior. On the basis of model, the numerical algorithm and code have been carried out to solve the plane boundary value problems. Examples of numerical simulations of stress-strain state of structural rock masses nearby a tunnel opening are presented. The deformation contours and isolines of stresses are plotted.
