针对机舱无线通信覆盖不全面、速度慢、不稳定等问题,该文基于射线跟踪方法构建了机舱环境第5代移动通信技术(5th generation mobile communication technology,5G)信道模型,并分析了信号覆盖能力及信道参数特性。首先,利用三角面元对...针对机舱无线通信覆盖不全面、速度慢、不稳定等问题,该文基于射线跟踪方法构建了机舱环境第5代移动通信技术(5th generation mobile communication technology,5G)信道模型,并分析了信号覆盖能力及信道参数特性。首先,利用三角面元对真实的机舱环境进行三维几何重构,以降低射线跟踪方法获取信道参数的复杂度;然后,结合分簇算法构建5G信道传播模型,进而分析了机舱环境下5G信号覆盖和通信性能。仿真分析结果表明,簇功率偏移和簇时延偏移服从高斯分布,簇到达方位角和簇到达俯仰角偏移服从拉普拉斯分布,同时发现,机舱环境中的密集散射体是影响5G信号覆盖范围的关键因素。上述结论可用于机舱环境5G基站的无线通信信号覆盖预测和多径参数评估等领域。展开更多
针对航空发动机高空环境模拟过渡态试验对高空舱进气环境压力模拟系统提出的强抗扰性、强鲁棒性等控制综合品质要求,设计了一种基于鲁棒模型预测控制(Robust Model Predictive Control,RMPC)的高空舱进气环境压力控制方法。RMPC采用滚...针对航空发动机高空环境模拟过渡态试验对高空舱进气环境压力模拟系统提出的强抗扰性、强鲁棒性等控制综合品质要求,设计了一种基于鲁棒模型预测控制(Robust Model Predictive Control,RMPC)的高空舱进气环境压力控制方法。RMPC采用滚动时域优化和扰动反馈补偿的方法,在预测控制框架内处理模型的不确定性。通过建立进气环境压力模拟系统设备特性模型,设计了基于RMPC的进气环境压力控制策略,搭建了仿真平台,与线性自抗扰控制(Linear Active Disturbance Rejection Control,LADRC)方法进行了对比分析。仿真结果表明,应用RMPC技术后,动态调节时间由7.68 s缩短至3.91 s,最大瞬时波动量由0.94%减小至0.25%,该技术能够大幅提高发动机高空环境模拟过渡态试验中进气环境压力模拟的动态响应速度、控制精度和抗扰能力。展开更多
目的旨在深入探究方舱工作人员的心理健康状况与院感风险事件发生率之间的关联。方法回顾性分析2022年8月至2022年12月期间,在我方舱医院参与工作的133名工作人员。评估他们入舱工作4周后的心理健康状况,并由失效模型与效应分析(failure...目的旨在深入探究方舱工作人员的心理健康状况与院感风险事件发生率之间的关联。方法回顾性分析2022年8月至2022年12月期间,在我方舱医院参与工作的133名工作人员。评估他们入舱工作4周后的心理健康状况,并由失效模型与效应分析(failure mode and effect analysis,FMEA)小组对其在随后4周内发生的院内感染风险事件进行统计及赋分,并通过ROC曲线确定的截断值将样本分为高院感风险事件组(n=44人)和低院感风险事件组(n=89人),采用独立样本t检验将方舱工作人员的心理健康状况与中国常模数据进行对比。逻辑回归分析探讨影响院内感染事件的危险因素。“rms”和pROC软件包建立和验证影响院内感染事件的预测模型。结果高院感风险事件组与低院感事件风险组在性别、年龄、工作区域、婚姻状态、人员类别等方面无显著差异(P>0.05),而心理健康水平显著较差(P<0.05)。结论方舱医院工作人员心理健康状况与其发生院感事件的风险相关,对于院感风险防控要求高的岗位应及时筛查并干预工作人员的心理健康状况,从而为更精准的管理决策提供支持。展开更多
Abstract Air distribution in commercial airliner cabins is very important for the comfort and health of passengers and crew. Experimental measurements, computational fluid dynamics （CFD） simulations, and inverse mod...Abstract Air distribution in commercial airliner cabins is very important for the comfort and health of passengers and crew. Experimental measurements, computational fluid dynamics （CFD） simulations, and inverse modeling are state-of-the-art methods available for studying the air distri- bution. This paper gave an overview of the different experimental models, such as scale models, simplified models, full-scale mockups, and actual air cabins. Although experimental measurements were expensive and time consuming, the data were essential for validating CFD simulations. Different modeling strategies for CFD simulations were also discussed in this paper, including large eddy simulations and Reynolds averaged Navier-Stokes equation modeling. CFD simulations were main stream approaches for studying the air distribution but they could not easily lead to optimal design. Inverse modeling of air distribution has recently emerged into a very powerful and attractive tool for designing the air distribution in airliner cabins, although most of the studies were preliminary.展开更多
Thermoregulatory mathematical models have being developed for more than half a century and obtained more and more wide application. Among them, the 'engineering-physiological' thermal models, which correlated ...Thermoregulatory mathematical models have being developed for more than half a century and obtained more and more wide application. Among them, the 'engineering-physiological' thermal models, which correlated closely to the man-machine-environment system, are the ones that developed most rapidly and have been widely accepted by thermal physiologists and environmental control engineers.This paper attempts to outline briefly the development and application of such kind of thermal models, discusses how to further develop and apply various combined thermal models in practice, and puts forward four respects of suggestions for establishment and modification of combined thermal models of man-clothing-cabin environment.展开更多
文摘针对机舱无线通信覆盖不全面、速度慢、不稳定等问题,该文基于射线跟踪方法构建了机舱环境第5代移动通信技术(5th generation mobile communication technology,5G)信道模型,并分析了信号覆盖能力及信道参数特性。首先,利用三角面元对真实的机舱环境进行三维几何重构,以降低射线跟踪方法获取信道参数的复杂度;然后,结合分簇算法构建5G信道传播模型,进而分析了机舱环境下5G信号覆盖和通信性能。仿真分析结果表明,簇功率偏移和簇时延偏移服从高斯分布,簇到达方位角和簇到达俯仰角偏移服从拉普拉斯分布,同时发现,机舱环境中的密集散射体是影响5G信号覆盖范围的关键因素。上述结论可用于机舱环境5G基站的无线通信信号覆盖预测和多径参数评估等领域。
文摘针对航空发动机高空环境模拟过渡态试验对高空舱进气环境压力模拟系统提出的强抗扰性、强鲁棒性等控制综合品质要求,设计了一种基于鲁棒模型预测控制(Robust Model Predictive Control,RMPC)的高空舱进气环境压力控制方法。RMPC采用滚动时域优化和扰动反馈补偿的方法,在预测控制框架内处理模型的不确定性。通过建立进气环境压力模拟系统设备特性模型,设计了基于RMPC的进气环境压力控制策略,搭建了仿真平台,与线性自抗扰控制(Linear Active Disturbance Rejection Control,LADRC)方法进行了对比分析。仿真结果表明,应用RMPC技术后,动态调节时间由7.68 s缩短至3.91 s,最大瞬时波动量由0.94%减小至0.25%,该技术能够大幅提高发动机高空环境模拟过渡态试验中进气环境压力模拟的动态响应速度、控制精度和抗扰能力。
文摘目的旨在深入探究方舱工作人员的心理健康状况与院感风险事件发生率之间的关联。方法回顾性分析2022年8月至2022年12月期间,在我方舱医院参与工作的133名工作人员。评估他们入舱工作4周后的心理健康状况,并由失效模型与效应分析(failure mode and effect analysis,FMEA)小组对其在随后4周内发生的院内感染风险事件进行统计及赋分,并通过ROC曲线确定的截断值将样本分为高院感风险事件组(n=44人)和低院感风险事件组(n=89人),采用独立样本t检验将方舱工作人员的心理健康状况与中国常模数据进行对比。逻辑回归分析探讨影响院内感染事件的危险因素。“rms”和pROC软件包建立和验证影响院内感染事件的预测模型。结果高院感风险事件组与低院感事件风险组在性别、年龄、工作区域、婚姻状态、人员类别等方面无显著差异(P>0.05),而心理健康水平显著较差(P<0.05)。结论方舱医院工作人员心理健康状况与其发生院感事件的风险相关,对于院感风险防控要求高的岗位应及时筛查并干预工作人员的心理健康状况,从而为更精准的管理决策提供支持。
基金supported by the National Basic Research Program of China(973 Program)(2012CB720100)
文摘Abstract Air distribution in commercial airliner cabins is very important for the comfort and health of passengers and crew. Experimental measurements, computational fluid dynamics （CFD） simulations, and inverse modeling are state-of-the-art methods available for studying the air distri- bution. This paper gave an overview of the different experimental models, such as scale models, simplified models, full-scale mockups, and actual air cabins. Although experimental measurements were expensive and time consuming, the data were essential for validating CFD simulations. Different modeling strategies for CFD simulations were also discussed in this paper, including large eddy simulations and Reynolds averaged Navier-Stokes equation modeling. CFD simulations were main stream approaches for studying the air distribution but they could not easily lead to optimal design. Inverse modeling of air distribution has recently emerged into a very powerful and attractive tool for designing the air distribution in airliner cabins, although most of the studies were preliminary.
文摘Thermoregulatory mathematical models have being developed for more than half a century and obtained more and more wide application. Among them, the 'engineering-physiological' thermal models, which correlated closely to the man-machine-environment system, are the ones that developed most rapidly and have been widely accepted by thermal physiologists and environmental control engineers.This paper attempts to outline briefly the development and application of such kind of thermal models, discusses how to further develop and apply various combined thermal models in practice, and puts forward four respects of suggestions for establishment and modification of combined thermal models of man-clothing-cabin environment.
