To address the defi ciency of climatological research on tropical cyclones （TCs） infl uencing China, we analyze the distributions of TCs with diff erent intensities in the region, based on the best-track TC data for...To address the defi ciency of climatological research on tropical cyclones （TCs） infl uencing China, we analyze the distributions of TCs with diff erent intensities in the region, based on the best-track TC data for 1949-2011 provided by the Shanghai Typhoon Institute. We also present the distributions of 50-and 100-yr return-period TCs with diff erent intensities using the Gumbel probability distribution. The results show that TCs with diff erent intensities exert distinctive eff ects on various regions of China and its surrounding waters. The extreme intensity distributions of TCs over these diff erent regions also diff er. Super and severe typhoons mainly infl uence Taiwan Island and coastal areas of Fujian and Zhejiang provinces, while typhoons and TCs with lower intensities infl uence South China most frequently. The probable maximum TC intensity （PMTI） with 50- and 100-yr return periods infl uencing Taiwan Island is below 890 hPa; the PMTI with a 50-yr return period infl uencing the coastal areas of Fujian and Zhejiang provinces is less than 910 hPa, and that with a 100-yr return period is less than 900 hPa;the PMTI with a 50-yr return period infl uencing the coastal areas of Hainan, Guangdong, and the northern part of the South China Sea is lower than 930 hPa, and that with a 100-yr return period is less than 920 hPa. The results provide a useful reference for the estimation of extreme TC intensities over diff erent regions of China.展开更多
This paper presents mathematics models that describe and optimize the passenger flow at the airport security checkpoints by applying the queuing theory. Firstly, a Poisson process is used to estimate the flow of passe...This paper presents mathematics models that describe and optimize the passenger flow at the airport security checkpoints by applying the queuing theory. Firstly, a Poisson process is used to estimate the flow of passengers waiting for going through the security. Then, the Poisson distribution is combined with a multiple M/M/s model. Following that, an arrival model (passengers’ arriving at the checkpoints preparing for security examination and departure) with Gumbel extreme value estimation is described that predicts the busiest time in the busiest airport. Real case data collected from several major airports worldwide is used for creating a hybrid Poisson model to generate the simulation of passenger volume. At last, Markov Chain theory is applied to the analysis to randomly simulate the flow of enplaned passengers again, and the results of these two simulations are compared and discussed, revealing that the hybrid Poisson model is the more accurate one. After successfully characterizing the passenger flow mathematically, two methods for optimizing the passenger flow are then provided in two different respects: one is bypassing passengers and creating an express pass;while the other one promotes Pre-Check service application.展开更多
The paper is concerned with the basic properties of multivariate extreme value distribution (in the Logistic model). We obtain the characteristic function and recurrence formula of the density function. The explicit a...The paper is concerned with the basic properties of multivariate extreme value distribution (in the Logistic model). We obtain the characteristic function and recurrence formula of the density function. The explicit algebraic formula for Fisher information matrix is indicated. A simple and accurate procedure for generating random vector from multivariate extreme value distribution is presented.展开更多
在逐次Ⅱ型截尾样本下,讨论以Gumbel极值分布为边缘分布,Gumbel Copula为连接函数的相依竞争失效模型参数的极大似然估计(MLE)和Bayes估计.对于参数MLE,提出与生存函数成正比的两阶段估计(Inference for the margins,IFM).对于Bayes估计...在逐次Ⅱ型截尾样本下,讨论以Gumbel极值分布为边缘分布,Gumbel Copula为连接函数的相依竞争失效模型参数的极大似然估计(MLE)和Bayes估计.对于参数MLE,提出与生存函数成正比的两阶段估计(Inference for the margins,IFM).对于Bayes估计,证明了Gumbel极值分布尺度参数的对数凹性,采用混合ARS(Adaptive Re-jection Sampling Algorithm)和MH(Metropolis-Hastings)抽样方法实现参数估计.模拟结果表明,当两失效机理关联性较弱时,两种估计结果相差不大,但关联性提高时,Bayes估计优于IFM估计.展开更多
A statistic method, statistics of extreme values （SEV）, was described in detail, which can esti mate the size of maximum inclusion in steel. The characteristic size of the maximum inclusion in a high clean bearing s...A statistic method, statistics of extreme values （SEV）, was described in detail, which can esti mate the size of maximum inclusion in steel. The characteristic size of the maximum inclusion in a high clean bearing steel （GCrl5） was evaluated by this method, and the morphology and corn position of large inclusions found were analyzed by scanning electron microscopy （SEM）. When standard inspection area （S0） is 280 mm2, the characteristic size of the biggest inclusion found in 30 standard inspection area is 23.93 μm, and it has a 99.9% probability of the characteristic size of maximum inclusion predicted being no larger than 36.85μm in the experimental steel. SEM result shows that large inclusions found are mainly composed of CaS, calcium-aluminate and MgO. Compositing widely exists in large inclusions in high clean bearing steel. Compared with traditional evaluation method, SEV method mainly focuses on inclusion size, and the esti- mation result is not affected by inclusion types. SEV method is suitable for the inclusion eval uation of high clean bearing steel.展开更多
基金Supported by the National(Key)Basic Research and Development(973)Program of China(2013CB430106)Key Project of National Social Science Foundation of China(11&zd167)
文摘To address the defi ciency of climatological research on tropical cyclones （TCs） infl uencing China, we analyze the distributions of TCs with diff erent intensities in the region, based on the best-track TC data for 1949-2011 provided by the Shanghai Typhoon Institute. We also present the distributions of 50-and 100-yr return-period TCs with diff erent intensities using the Gumbel probability distribution. The results show that TCs with diff erent intensities exert distinctive eff ects on various regions of China and its surrounding waters. The extreme intensity distributions of TCs over these diff erent regions also diff er. Super and severe typhoons mainly infl uence Taiwan Island and coastal areas of Fujian and Zhejiang provinces, while typhoons and TCs with lower intensities infl uence South China most frequently. The probable maximum TC intensity （PMTI） with 50- and 100-yr return periods infl uencing Taiwan Island is below 890 hPa; the PMTI with a 50-yr return period infl uencing the coastal areas of Fujian and Zhejiang provinces is less than 910 hPa, and that with a 100-yr return period is less than 900 hPa;the PMTI with a 50-yr return period infl uencing the coastal areas of Hainan, Guangdong, and the northern part of the South China Sea is lower than 930 hPa, and that with a 100-yr return period is less than 920 hPa. The results provide a useful reference for the estimation of extreme TC intensities over diff erent regions of China.
文摘This paper presents mathematics models that describe and optimize the passenger flow at the airport security checkpoints by applying the queuing theory. Firstly, a Poisson process is used to estimate the flow of passengers waiting for going through the security. Then, the Poisson distribution is combined with a multiple M/M/s model. Following that, an arrival model (passengers’ arriving at the checkpoints preparing for security examination and departure) with Gumbel extreme value estimation is described that predicts the busiest time in the busiest airport. Real case data collected from several major airports worldwide is used for creating a hybrid Poisson model to generate the simulation of passenger volume. At last, Markov Chain theory is applied to the analysis to randomly simulate the flow of enplaned passengers again, and the results of these two simulations are compared and discussed, revealing that the hybrid Poisson model is the more accurate one. After successfully characterizing the passenger flow mathematically, two methods for optimizing the passenger flow are then provided in two different respects: one is bypassing passengers and creating an express pass;while the other one promotes Pre-Check service application.
文摘The paper is concerned with the basic properties of multivariate extreme value distribution (in the Logistic model). We obtain the characteristic function and recurrence formula of the density function. The explicit algebraic formula for Fisher information matrix is indicated. A simple and accurate procedure for generating random vector from multivariate extreme value distribution is presented.
文摘在逐次Ⅱ型截尾样本下,讨论以Gumbel极值分布为边缘分布,Gumbel Copula为连接函数的相依竞争失效模型参数的极大似然估计(MLE)和Bayes估计.对于参数MLE,提出与生存函数成正比的两阶段估计(Inference for the margins,IFM).对于Bayes估计,证明了Gumbel极值分布尺度参数的对数凹性,采用混合ARS(Adaptive Re-jection Sampling Algorithm)和MH(Metropolis-Hastings)抽样方法实现参数估计.模拟结果表明,当两失效机理关联性较弱时,两种估计结果相差不大,但关联性提高时,Bayes估计优于IFM估计.
基金funded by National Natural Science Foundation of China(51474076)International S&T Cooperation Program(ISTCP)of China(2015DFG51950)
文摘A statistic method, statistics of extreme values （SEV）, was described in detail, which can esti mate the size of maximum inclusion in steel. The characteristic size of the maximum inclusion in a high clean bearing steel （GCrl5） was evaluated by this method, and the morphology and corn position of large inclusions found were analyzed by scanning electron microscopy （SEM）. When standard inspection area （S0） is 280 mm2, the characteristic size of the biggest inclusion found in 30 standard inspection area is 23.93 μm, and it has a 99.9% probability of the characteristic size of maximum inclusion predicted being no larger than 36.85μm in the experimental steel. SEM result shows that large inclusions found are mainly composed of CaS, calcium-aluminate and MgO. Compositing widely exists in large inclusions in high clean bearing steel. Compared with traditional evaluation method, SEV method mainly focuses on inclusion size, and the esti- mation result is not affected by inclusion types. SEV method is suitable for the inclusion eval uation of high clean bearing steel.
