This paper analyzes the seismicity and seismic risk distribution in the Bohai Sea. Based on the seismic design parameters of 46 platforms in the Bohai Sea, a statistic analysis is made on the ratios of the peak accele...This paper analyzes the seismicity and seismic risk distribution in the Bohai Sea. Based on the seismic design parameters of 46 platforms in the Bohai Sea, a statistic analysis is made on the ratios of the peak accelerations for different probability levels. In accordance with the two-stage design method, a scheme of two design seismic levels is proposed, and two fortification goals are established respectively for strength level earthquakes and ductility level earthquakes. Through analogy and comparison to the Chinese seismic code for buildings, it is proposed that the probability level for the strength and ductility level earthquakes takes return periods of 200a and 1000～2500a respectively, and we further expounded on its rationality. Finally, the fortification parameters in the sub-regions of Bohai Sea area are given in the light of seismic risk zonation and ground motion division. This article is a summary of experiences from many years of offshore platform seismic fortification work, and an exploratory study on the seismic fortification standards of offshore platforms in China, which may provide some references for the establishment of the standard.展开更多
In this study, the North China seismic region was selected as the study area, and evaluation of seismic hazard using the spatial smoothing seismicity model was performed. Firstly, the study area is divided into grids,...In this study, the North China seismic region was selected as the study area, and evaluation of seismic hazard using the spatial smoothing seismicity model was performed. Firstly, the study area is divided into grids, and some parameters （e. g. b-value, Mo, Me, azimuth and M-L relationship ） for each seismotectonic model were assigned. Secondly, using elliptical smoothing based on a seismotectonic background model, the statistical earthquake incidence rate in each grid is successively calculated. Lastly, the relevant ground motion attenuation relationship is chosen to assess seismic hazard of general sites. The maps for the distribution of horizontal peak ground acceleration with 10% probability of exceedance in 50 years were obtained by using the seismic hazard analysis method based on grid source. This seismicity model simplifies the methodology of probabilistic seismic hazard analysis, especially appropriate for those places where seismic tectonics is not yet clearly known. This method can provide valuable references for seismic zonation and seismic safety assessment for significant engineering projects.展开更多
In this article, clustered recurrent gap time is investigated. A marginal additive haz- ards model is proposed without specifying the association of the individuals within the same cluster. The relationship among the ...In this article, clustered recurrent gap time is investigated. A marginal additive haz- ards model is proposed without specifying the association of the individuals within the same cluster. The relationship among the gap times for the same individual is also left unspecified. An estimating equation-based inference procedure is developed for the model parameters, and the asymptotic proper- ties of the resulting estimators are established. In addition, a lack-of-fit test is presented to assess the adequacy of the model. The finite sample behavior of the proposed estimators is evaluated through simulation studies, and an application to a clinic study on chronic granulomatous disease （CGD） is illustrated.展开更多
This paper studies a maintenance model for an one-unit degenerative system with multiple failure states based on the proportional hazards and proportional reversed hazards models. The authors investigate how the varia...This paper studies a maintenance model for an one-unit degenerative system with multiple failure states based on the proportional hazards and proportional reversed hazards models. The authors investigate how the variation of system configuration parameters have an impact on both operating and repair times and hence the system performance. Furthermore, the authors also derive the explicit expression for the long-run average cost per unit time. An algorithm to locate the optimal number of repairs in a renewal cycle is discussed as well.展开更多
基金Funding for this research(NEXTRANS Project No.051WY02) was provided by the NEXTRANS University Transportation Center,Purdue University,Indiana under Grant No.DTRT07-G-005 of the U.S. Department of Transportation,Research and Innovative Technology Administration(RITA), University Transportation Centers Program
基金Supported by Special Scientific Research of Public Welfare Profession of Ministry of Finance,the People's Republic of China(200708055)
文摘This paper analyzes the seismicity and seismic risk distribution in the Bohai Sea. Based on the seismic design parameters of 46 platforms in the Bohai Sea, a statistic analysis is made on the ratios of the peak accelerations for different probability levels. In accordance with the two-stage design method, a scheme of two design seismic levels is proposed, and two fortification goals are established respectively for strength level earthquakes and ductility level earthquakes. Through analogy and comparison to the Chinese seismic code for buildings, it is proposed that the probability level for the strength and ductility level earthquakes takes return periods of 200a and 1000～2500a respectively, and we further expounded on its rationality. Finally, the fortification parameters in the sub-regions of Bohai Sea area are given in the light of seismic risk zonation and ground motion division. This article is a summary of experiences from many years of offshore platform seismic fortification work, and an exploratory study on the seismic fortification standards of offshore platforms in China, which may provide some references for the establishment of the standard.
基金funded by the Special Fund for Fundamental Research of Central-level Public Interest Institutions,China(ZDJ2011-13)
文摘In this study, the North China seismic region was selected as the study area, and evaluation of seismic hazard using the spatial smoothing seismicity model was performed. Firstly, the study area is divided into grids, and some parameters （e. g. b-value, Mo, Me, azimuth and M-L relationship ） for each seismotectonic model were assigned. Secondly, using elliptical smoothing based on a seismotectonic background model, the statistical earthquake incidence rate in each grid is successively calculated. Lastly, the relevant ground motion attenuation relationship is chosen to assess seismic hazard of general sites. The maps for the distribution of horizontal peak ground acceleration with 10% probability of exceedance in 50 years were obtained by using the seismic hazard analysis method based on grid source. This seismicity model simplifies the methodology of probabilistic seismic hazard analysis, especially appropriate for those places where seismic tectonics is not yet clearly known. This method can provide valuable references for seismic zonation and seismic safety assessment for significant engineering projects.
基金supported by the National Natural Science Foundation of China under Grant Nos.11501037,11771431,and 11690015
文摘In this article, clustered recurrent gap time is investigated. A marginal additive haz- ards model is proposed without specifying the association of the individuals within the same cluster. The relationship among the gap times for the same individual is also left unspecified. An estimating equation-based inference procedure is developed for the model parameters, and the asymptotic proper- ties of the resulting estimators are established. In addition, a lack-of-fit test is presented to assess the adequacy of the model. The finite sample behavior of the proposed estimators is evaluated through simulation studies, and an application to a clinic study on chronic granulomatous disease （CGD） is illustrated.
基金supported by the National Natural Science Foundation of China under Grant No.11422109
文摘This paper studies a maintenance model for an one-unit degenerative system with multiple failure states based on the proportional hazards and proportional reversed hazards models. The authors investigate how the variation of system configuration parameters have an impact on both operating and repair times and hence the system performance. Furthermore, the authors also derive the explicit expression for the long-run average cost per unit time. An algorithm to locate the optimal number of repairs in a renewal cycle is discussed as well.
