The zero_failure data research is a new field in the recent years, but it is required urgently in practical projects, so the work has more theory and practical values. In this paper, for zero_failure data (t i,n i...The zero_failure data research is a new field in the recent years, but it is required urgently in practical projects, so the work has more theory and practical values. In this paper, for zero_failure data (t i,n i) at moment t i , if the prior distribution of the failure probability p i=p{T【t i} is quasi_exponential distribution, the author gives the p i Bayesian estimation and hierarchical Bayesian estimation and the reliability under zero_failure date condition is also obtained.展开更多
The objective of this study was to estimate natural, fishing and total mortality, survival and exploitation rates of Clupeonella engrauliformis in the southern Caspian Sea. Survival rate and natural mortality were cal...The objective of this study was to estimate natural, fishing and total mortality, survival and exploitation rates of Clupeonella engrauliformis in the southern Caspian Sea. Survival rate and natural mortality were calculated using catch curve and Pauly methods, respectively. Natural and fishing mortality have been estimated up to 0.633 yr^-1 and 0.437 yr^-1, respectively. According to catch curve method, the annual survival rate of anchovy kilka has been estimated up to 0.343 yr^-1. With owning this survival rate, the instantaneous coefficient of total mortality of anchovy kilka has been estimated up to 1.07 yr^-1. The exploitation rate of anchovy kilka has been estimated up to 0.408. The catch amounts of anchovy kilka decreased gradually mainly due to overfishing, predators and ecological disturbances occurred in the Caspian Sea. The results suggest that the population of anchovy kilka were overexploited in the past years and were vulnerable to their natural predators.展开更多
The multiply type-I censoring represented that all units in life test were terminated at different times. For estimations of Weibull parameters, it was easy to compute the maximum likelihood estimation （MLE） and lea...The multiply type-I censoring represented that all units in life test were terminated at different times. For estimations of Weibull parameters, it was easy to compute the maximum likelihood estimation （MLE） and least-squares estimation （LSE） while it was hard to build confidence intervals （CI）. The concept of generalized confidence interval （GCI） was introduced to build CIs of parameters under multiply type-I censoring. Further, GCI based on LSE and GCI based on MLE were proposed. It is mathematically proved that the former is exact and the latter is approximate. Besides, a Monte Carlo simulation study and an illustrative example also Ran out that the GCI method based on LSE yields rather satisfactory results by comparison with the ones based on MLE. It should be clear that the GCI method is a sensible choice to evaluate reliability under multiply type-I censoring.展开更多
文摘The zero_failure data research is a new field in the recent years, but it is required urgently in practical projects, so the work has more theory and practical values. In this paper, for zero_failure data (t i,n i) at moment t i , if the prior distribution of the failure probability p i=p{T【t i} is quasi_exponential distribution, the author gives the p i Bayesian estimation and hierarchical Bayesian estimation and the reliability under zero_failure date condition is also obtained.
文摘The objective of this study was to estimate natural, fishing and total mortality, survival and exploitation rates of Clupeonella engrauliformis in the southern Caspian Sea. Survival rate and natural mortality were calculated using catch curve and Pauly methods, respectively. Natural and fishing mortality have been estimated up to 0.633 yr^-1 and 0.437 yr^-1, respectively. According to catch curve method, the annual survival rate of anchovy kilka has been estimated up to 0.343 yr^-1. With owning this survival rate, the instantaneous coefficient of total mortality of anchovy kilka has been estimated up to 1.07 yr^-1. The exploitation rate of anchovy kilka has been estimated up to 0.408. The catch amounts of anchovy kilka decreased gradually mainly due to overfishing, predators and ecological disturbances occurred in the Caspian Sea. The results suggest that the population of anchovy kilka were overexploited in the past years and were vulnerable to their natural predators.
基金Project(71371182) supported by the National Natural Science Foundation of China
文摘The multiply type-I censoring represented that all units in life test were terminated at different times. For estimations of Weibull parameters, it was easy to compute the maximum likelihood estimation （MLE） and least-squares estimation （LSE） while it was hard to build confidence intervals （CI）. The concept of generalized confidence interval （GCI） was introduced to build CIs of parameters under multiply type-I censoring. Further, GCI based on LSE and GCI based on MLE were proposed. It is mathematically proved that the former is exact and the latter is approximate. Besides, a Monte Carlo simulation study and an illustrative example also Ran out that the GCI method based on LSE yields rather satisfactory results by comparison with the ones based on MLE. It should be clear that the GCI method is a sensible choice to evaluate reliability under multiply type-I censoring.
