It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present...It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present a multi-ray propagation model for UWB signal,which is traveling through the human thorax and is reflected on the air/dry-skin/fat/muscle interfaces,A geometry-based statistical channel model is then developed for simulating the reception of UWB signals in the indoor propagation environment.This model enables replication of time-varying multipath profiles due to the displacement of a human chest.Subsequently, a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate.The analytical framework can serve as a basis in the planning and evaluation of future rheasurement programs.We also provide a case study on how the antenna beamwidth affects the estimation of respiration rate based on the proposed propagation models and system architecture.展开更多
The magnetic flux in a permanent magnet transverse flux generator(PMTFG) is three-dimensional(3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method(FEM) is h...The magnetic flux in a permanent magnet transverse flux generator(PMTFG) is three-dimensional(3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method(FEM) is highly accurate and reliable for machine simulation, it requires a long computation time, which is crucial when it is to be used in an iterative optimization process. Therefore, an alternative to 3DFEM is required as a rapid and accurate analytical technique. This paper presents an analytical model for PMTFG analysis using winding function method. To obtain the air gap MMF distribution, the excitation magneto-motive force(MMF) and the turn function are determined based on certain assumptions. The magnetizing inductance, flux density, and back-electro-magnetomotive force of the winding are then determined. To assess the accuracy of the proposed method, the analytically calculated parameters of the generator are compared to those obtained by a 3D-FEM. The presented method requires significantly shorter computation time than the 3D-FEM with comparable accuracy.展开更多
目的探讨青年OSAHS患者缺氧程度与认知功能的相关性。方法选取OSAHS患者63例,年龄18～44岁。根据OSAHS患者的低氧血症程度,将患者分为轻度组20例(最低SaO2≥85%),中度组24例(最低SaO265%～84%),重度组19例(最低SaO2<65%);对照组25例...目的探讨青年OSAHS患者缺氧程度与认知功能的相关性。方法选取OSAHS患者63例,年龄18～44岁。根据OSAHS患者的低氧血症程度,将患者分为轻度组20例(最低SaO2≥85%),中度组24例(最低SaO265%～84%),重度组19例(最低SaO2<65%);对照组25例(正常人:AHI<5)。均进行事件相关电位P300、多导睡眠图(polysomnogram,PSG)和简易智能精神状态检查量表(mini-mental state examination,MMSE)检测。结果①OSAHS患者轻度、中度、重度三组P300潜伏期分别为326.1±12.7、346.9±19.1、334.9±18.3ms,与对照组311.9±18.3ms比较差异均有统计学意义(皆P<0.05),OSAHS轻、中度组与重度组之间差异均有统计学意义(P<0.01或P<0.05),但轻度组和中度组患者之间差异无统计学意义(P=0.095);②重度组中因最低血氧持续时间的不同P300潜伏期不同:最低血氧持续时间4～60秒组潜伏期为338.12±13.7ms,最低血氧持续时间61～140秒组潜伏期为354.74±16.7ms,差异有统计学意义(P=0.031);③以上各组P300波幅之间比较差异无统计学意义;④所有患者MESS得分均在正常范围内,但部分得分稍低,重度组与对照组得分比较差异有统计学意义(R-A-R-B=9.91,P=0.003)。结论OSAHS患者普遍存在认知功能障碍,可以最低血氧程度及其持续时间初步评估认知功能损害的程度。展开更多
文摘It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present a multi-ray propagation model for UWB signal,which is traveling through the human thorax and is reflected on the air/dry-skin/fat/muscle interfaces,A geometry-based statistical channel model is then developed for simulating the reception of UWB signals in the indoor propagation environment.This model enables replication of time-varying multipath profiles due to the displacement of a human chest.Subsequently, a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate.The analytical framework can serve as a basis in the planning and evaluation of future rheasurement programs.We also provide a case study on how the antenna beamwidth affects the estimation of respiration rate based on the proposed propagation models and system architecture.
文摘The magnetic flux in a permanent magnet transverse flux generator(PMTFG) is three-dimensional(3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method(FEM) is highly accurate and reliable for machine simulation, it requires a long computation time, which is crucial when it is to be used in an iterative optimization process. Therefore, an alternative to 3DFEM is required as a rapid and accurate analytical technique. This paper presents an analytical model for PMTFG analysis using winding function method. To obtain the air gap MMF distribution, the excitation magneto-motive force(MMF) and the turn function are determined based on certain assumptions. The magnetizing inductance, flux density, and back-electro-magnetomotive force of the winding are then determined. To assess the accuracy of the proposed method, the analytically calculated parameters of the generator are compared to those obtained by a 3D-FEM. The presented method requires significantly shorter computation time than the 3D-FEM with comparable accuracy.
文摘目的探讨青年OSAHS患者缺氧程度与认知功能的相关性。方法选取OSAHS患者63例,年龄18～44岁。根据OSAHS患者的低氧血症程度,将患者分为轻度组20例(最低SaO2≥85%),中度组24例(最低SaO265%～84%),重度组19例(最低SaO2<65%);对照组25例(正常人:AHI<5)。均进行事件相关电位P300、多导睡眠图(polysomnogram,PSG)和简易智能精神状态检查量表(mini-mental state examination,MMSE)检测。结果①OSAHS患者轻度、中度、重度三组P300潜伏期分别为326.1±12.7、346.9±19.1、334.9±18.3ms,与对照组311.9±18.3ms比较差异均有统计学意义(皆P<0.05),OSAHS轻、中度组与重度组之间差异均有统计学意义(P<0.01或P<0.05),但轻度组和中度组患者之间差异无统计学意义(P=0.095);②重度组中因最低血氧持续时间的不同P300潜伏期不同:最低血氧持续时间4～60秒组潜伏期为338.12±13.7ms,最低血氧持续时间61～140秒组潜伏期为354.74±16.7ms,差异有统计学意义(P=0.031);③以上各组P300波幅之间比较差异无统计学意义;④所有患者MESS得分均在正常范围内,但部分得分稍低,重度组与对照组得分比较差异有统计学意义(R-A-R-B=9.91,P=0.003)。结论OSAHS患者普遍存在认知功能障碍,可以最低血氧程度及其持续时间初步评估认知功能损害的程度。
