Modeling log-mortality rates on O-U type processes and forecasting life expectancies are explored using U.S. data. In the classic Lee-Carter model of mortality, the time trend and the age-specific pattern of mortality...Modeling log-mortality rates on O-U type processes and forecasting life expectancies are explored using U.S. data. In the classic Lee-Carter model of mortality, the time trend and the age-specific pattern of mortality over age group are linear, this is not the feature of mortality model. To avoid this disadvantage, O-U type processes will be used to model the log-mortality in this paper. In fact, this model is an AR(1) process, but with a nonlinear time drift term.Based on the mortality data of America from Human Mortality database(HMD), mortality projection consistently indicates a preference for mortality with O-U type processes over those with the classical Lee-Carter model. By means of this model, the low bounds of mortality rates at every age are given. Therefore, lengthening of maximum life expectancies span is estimated in this paper.展开更多
In order to explore the propagation law of gas explosion in U type laneways,the propagation law of flame and shock wave in U type duct were experimentally and theoret- ically investigated.It is shown that the shock wa...In order to explore the propagation law of gas explosion in U type laneways,the propagation law of flame and shock wave in U type duct were experimentally and theoret- ically investigated.It is shown that the shock wave takes on the complicated stress state and the flame takes on complicated change rules in the U type duct.The propagation process of gas explosion in bend duct is the mutual action of explosion wave,flame and complicate flow,the destruction in bend surface is especially serious.In the mine exploita- tion and laneway design,the bend laneway should be avoided,especially continuous bend laneway.展开更多
基金Supported by National Social Science Fund of China(17BTJ023)
文摘Modeling log-mortality rates on O-U type processes and forecasting life expectancies are explored using U.S. data. In the classic Lee-Carter model of mortality, the time trend and the age-specific pattern of mortality over age group are linear, this is not the feature of mortality model. To avoid this disadvantage, O-U type processes will be used to model the log-mortality in this paper. In fact, this model is an AR(1) process, but with a nonlinear time drift term.Based on the mortality data of America from Human Mortality database(HMD), mortality projection consistently indicates a preference for mortality with O-U type processes over those with the classical Lee-Carter model. By means of this model, the low bounds of mortality rates at every age are given. Therefore, lengthening of maximum life expectancies span is estimated in this paper.
基金the National Natural Science Foundation of China(50674047,50534090,50574093)State Key Base Development Plan(2005CB221506)
文摘In order to explore the propagation law of gas explosion in U type laneways,the propagation law of flame and shock wave in U type duct were experimentally and theoret- ically investigated.It is shown that the shock wave takes on the complicated stress state and the flame takes on complicated change rules in the U type duct.The propagation process of gas explosion in bend duct is the mutual action of explosion wave,flame and complicate flow,the destruction in bend surface is especially serious.In the mine exploita- tion and laneway design,the bend laneway should be avoided,especially continuous bend laneway.
