This paper theoretically explores the effect of PM2.5 air pollution on the phase precision of a Mach-Zehnder inter- ferometer. With the increasing of PM2.5 concentration, phase precision for inputs of coherent state ...This paper theoretically explores the effect of PM2.5 air pollution on the phase precision of a Mach-Zehnder inter- ferometer. With the increasing of PM2.5 concentration, phase precision for inputs of coherent state & vacuum state and inputs of coherent state & squeezed vacuum state will gradually decrease and be lower than the standard quantum limit. When the value of relative humidity is increasing, the precision of two input cases is decreasing much faster. We also find that the precision for inputs of coherent state & squeezed state is better than that of coherent state & vacuum state when PM2.5 concentration is lower. As PM2.5 concentration increases, the precision for inputs of coherent state & squeezed state decreases faster, and then the two precisions tend to be the same while the concentration is higher.展开更多
为了解决航天发射场复杂可维修多阶段任务系统(phased-mission system,PMS)的任务可靠性评估问题,依据考虑维修的多阶段任务系统(phased-mission system considering maintenance,PMSCM)理论和蒙特卡罗方法,基于系统特殊的任务成功定义...为了解决航天发射场复杂可维修多阶段任务系统(phased-mission system,PMS)的任务可靠性评估问题,依据考虑维修的多阶段任务系统(phased-mission system considering maintenance,PMSCM)理论和蒙特卡罗方法,基于系统特殊的任务成功定义规则,通过任务阶段的形式化描述与零部件的虚节点处理,建立可靠性评估仿真模型。将模型应用于航天发射场垂直总装厂房液压系统,成功分析了系统多阶段任务的可靠性均值、方差和置信区间。仿真结果表明:该模型能够找出系统的关键部件,为垂直总装厂房及航天发射场系统总体任务进行可靠性预计、分配和评估提供重要参考和决策支持。展开更多
This paper presents a modeling method by stochastic Petri net for reliability analysis of phased mission system( PMS) with phase backup. The model consisting of petri nets,depicts the system behaviors of unit level,sy...This paper presents a modeling method by stochastic Petri net for reliability analysis of phased mission system( PMS) with phase backup. The model consisting of petri nets,depicts the system behaviors of unit level,system logic level and phase level. Guard functions of petri nets are used to avoid modeling complexity and make the model flexible to different reliability logical structures. It was shown that the time redundancy within phase and from phase backup for PMS can both be described by use of the proposed model.展开更多
电光相位调制器(Phase Modulator,PM)因无需偏置,线性调制和插损小等优点,被广泛应用于相干光通信、微波信号产生、处理和测量等领域.调制指数和半波电压是评估PM性能的关键参数.传统基于(Optical Spectrum Analyzer,OSA)的方法面临测...电光相位调制器(Phase Modulator,PM)因无需偏置,线性调制和插损小等优点,被广泛应用于相干光通信、微波信号产生、处理和测量等领域.调制指数和半波电压是评估PM性能的关键参数.传统基于(Optical Spectrum Analyzer,OSA)的方法面临测量分辨率低和存在测量盲区问题.为此,本文提出了一种基于电谱分析(Unequal Voltage based on Electrical Spectrum Analyzer,UV-ESA)的自校准、高精度的PM特性参数测量方法.该方法利用同频、不同驱动电压比的情况下,通过分析失谐光学载波和调制边带分别与载波拍音电谱,实现PM调制指数和半波电压的高频特性参数测量.该方法不需改变测量链路结构,无需辅助宽带微波源或电光调制器,验证了所提方法的有效性,并对比OSA方法对结果的准确性进行了验证.展开更多
A comprehensive mission sensitivity analysis index based on Sobol's index called global mission sensitivity( GMS) was proposed in this paper which focused on analyzing the mission sensitivity of components of phas...A comprehensive mission sensitivity analysis index based on Sobol's index called global mission sensitivity( GMS) was proposed in this paper which focused on analyzing the mission sensitivity of components of phased mission systems( PMS). The simulation strategy of GMS based on a Petri net and Monte Carlo method was presented which had broad applicability. Finally,the GMS and Birnbaum's sensitivity of components in a PMS example were compared. The GMS of component is demonstrated to be more adaptable to reflect the component mission sensitivity when the rated reliability parameters of components cannot be obtained, and components have state dependency or the system is subjected to common cause failure.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61306131)the Science Foundation of Shaanxi Provincial Department of Education,China(Grant No.14JK1682)
文摘This paper theoretically explores the effect of PM2.5 air pollution on the phase precision of a Mach-Zehnder inter- ferometer. With the increasing of PM2.5 concentration, phase precision for inputs of coherent state & vacuum state and inputs of coherent state & squeezed vacuum state will gradually decrease and be lower than the standard quantum limit. When the value of relative humidity is increasing, the precision of two input cases is decreasing much faster. We also find that the precision for inputs of coherent state & squeezed state is better than that of coherent state & vacuum state when PM2.5 concentration is lower. As PM2.5 concentration increases, the precision for inputs of coherent state & squeezed state decreases faster, and then the two precisions tend to be the same while the concentration is higher.
文摘为了解决航天发射场复杂可维修多阶段任务系统(phased-mission system,PMS)的任务可靠性评估问题,依据考虑维修的多阶段任务系统(phased-mission system considering maintenance,PMSCM)理论和蒙特卡罗方法,基于系统特殊的任务成功定义规则,通过任务阶段的形式化描述与零部件的虚节点处理,建立可靠性评估仿真模型。将模型应用于航天发射场垂直总装厂房液压系统,成功分析了系统多阶段任务的可靠性均值、方差和置信区间。仿真结果表明:该模型能够找出系统的关键部件,为垂直总装厂房及航天发射场系统总体任务进行可靠性预计、分配和评估提供重要参考和决策支持。
基金Nationd Natural Science Foundation of China(No.71671185)
文摘This paper presents a modeling method by stochastic Petri net for reliability analysis of phased mission system( PMS) with phase backup. The model consisting of petri nets,depicts the system behaviors of unit level,system logic level and phase level. Guard functions of petri nets are used to avoid modeling complexity and make the model flexible to different reliability logical structures. It was shown that the time redundancy within phase and from phase backup for PMS can both be described by use of the proposed model.
文摘电光相位调制器(Phase Modulator,PM)因无需偏置,线性调制和插损小等优点,被广泛应用于相干光通信、微波信号产生、处理和测量等领域.调制指数和半波电压是评估PM性能的关键参数.传统基于(Optical Spectrum Analyzer,OSA)的方法面临测量分辨率低和存在测量盲区问题.为此,本文提出了一种基于电谱分析(Unequal Voltage based on Electrical Spectrum Analyzer,UV-ESA)的自校准、高精度的PM特性参数测量方法.该方法利用同频、不同驱动电压比的情况下,通过分析失谐光学载波和调制边带分别与载波拍音电谱,实现PM调制指数和半波电压的高频特性参数测量.该方法不需改变测量链路结构,无需辅助宽带微波源或电光调制器,验证了所提方法的有效性,并对比OSA方法对结果的准确性进行了验证.
基金National Natural Science Foundation of China(No.71071159)
文摘A comprehensive mission sensitivity analysis index based on Sobol's index called global mission sensitivity( GMS) was proposed in this paper which focused on analyzing the mission sensitivity of components of phased mission systems( PMS). The simulation strategy of GMS based on a Petri net and Monte Carlo method was presented which had broad applicability. Finally,the GMS and Birnbaum's sensitivity of components in a PMS example were compared. The GMS of component is demonstrated to be more adaptable to reflect the component mission sensitivity when the rated reliability parameters of components cannot be obtained, and components have state dependency or the system is subjected to common cause failure.