A Numerical Investigation into the Spread Characteristics of a Human Virus-Carrying Droplet in a Classroom Environment.

In public health, the transmission characteristics and laws of highly infectious virus-carrying particles in the air environment have become a hot topic. The study on the spread characteristics of human virus-carrying droplets in a typical densely populated space is necessary. As such, a classroom space lattice Boltzmann method (LBM) model with a dense population is established to simulate and analyze the spreading and diffusing behavior of pathogenic droplets. The results show that the dispersion density is mainly affected by the mainstream wind direction in the area of concern, and particle aggregation is more likely to form in the area close to the wind disturbance. Due to the dense thermal plumes, the droplet movement is a clear convergence towards the upper space of the classroom. This could explain the fact that people living above confirmed cases are now more likely to be infected.

Enhanced monocular visual odometry integrated with laser distance meter for astronaut navigation.

Visual odometry provides astronauts with accurate knowledge of their position and orientation. Wearable astronaut navigation systems should be simple and compact. Therefore, monocular vision methods are preferred over stereo vision systems, commonly used in mobile robots. However, the projective nature of monocular visual odometry causes a scale ambiguity problem. In this paper, we focus on the integration of a monocular camera with a laser distance meter to solve this problem. The most remarkable advantage of the system is its ability to recover a global trajectory for monocular image sequences by incorporating direct distance measurements. First, we propose a robust and easy-to-use extrinsic calibration method between camera and laser distance meter. Second, we present a navigation scheme that fuses distance measurements with monocular sequences to correct the scale drift. In particular, we explain in detail how to match the projection of the invisible laser pointer on other frames. Our proposed integration architecture is examined using a live dataset collected in a simulated lunar surface environment. The experimental results demonstrate the feasibility and effectiveness of the proposed method.

Characterization of maternal body movement during sleep before and after parturition.

The purpose of this study was to characterize the different features of body movements for females before and after parturition. Body movement signal was measured by a piezoelectric sensor board which was deployed on the abdominal position beneath a mattress during sleep to monitor pressure changes around abdominal area. Body movement epochs were detected by an innovative algorithm based on Hilbert transform. Data were collected from two healthy pregnant females during sleep for 7 weeks before parturition and 6 weeks after parturition. The pressure signal was used to determine the duration and time interval of maternal movements. Characteristics of the detected body movements before and after parturition were investigated through their proportion. The results showed that before and after parturition, the body movement which features as 0~1 min in interval and 0~6 sec in duration has significant difference statistically. It is considered that these differences are highly correlated with the prenatal activities.

Performance assessment on different measurement positions for monitoring HR/RR during sleep.

This study aims to investigate the measurement performance on different sensor deployment and to determine the optimal position for monitoring heart rate (HR) and respiration rate (RR) during sleep. Five identical sensor boards were deployed on different positions simultaneously during sleep to detect changes of applied pressure due to heart beating and breathing. One board was set beneath the pillow; the other four boards were set under the mattress aligning with the head, back, hip and calf, respectively. Data were collected from five healthy subjects during a 2-hour's nap individually. Detection performance was evaluated by sensitivity and positive predictivity. The results showed that nearly all of the positions could be used to detect heart rate; both sensitivity and positive predictivity were over 85% among five persons. All of the positions could be used to detect respiration rate except for calf. The highest performance of sensitivity and positive predictivity in respiration rate detection could be found in the hip position, which reached as high as 99%. The optimal position with overall best performance for HR and RR measurement is considered in the hip.

[Suitability evaluation of Panax quinquefolium's producing area based on TCMGIS- I].

OBJECTIVE: To supply the scientific data for the choice of medicinal plants' producing area through analyzing the suitable area for Panax quinquefolium' growth. METHOD: TCMGIS-I (Suitability evaluation geographic information system of traditional Chinese medicine producing area) was developed and used to analyze the suitable producing area of P. quinquefolium Wisconsin state of USA, one of the origin producing area of the geo-authentic crude drugs, was selected as the standard analytical area and some key factors related to plant growth such as average temperature, altitude, soil type, precipitation were chosen to be considered. RESULT: The result showed that the suitable area for P. quinquefolium' growth in China is similar to the present status. It concentrates in the northeast and the north of China, and part of Shanxi province is also suitable but the field area is small. CONCLUSION: The development of P. quinquefolium in China should concentrate in the northeast and the north of China. The TCMGIS-I is valuable to the analysis of suitable producing area and introduction of medicinal plant.