Energy harvesting is an area of substantial and increasing research attention, and vibration-based devices dominate this research. The primary goal of most researchers is producing maximum electrical output from the h...Energy harvesting is an area of substantial and increasing research attention, and vibration-based devices dominate this research. The primary goal of most researchers is producing maximum electrical output from the harvester systems. However, there have been little metrological considerations for circumstances under which the energy harvester devices are characterized. This makes comparison of different device prototypes very difficult. It is the focus of this paper to highlight the need for metrological considerations to energy harvesting so that a universal metric can be developed. An attempt is also made to discuss the critical parameters that are essential in establishing an international standard on vibration-based energy harvesting. Finally, a simple standard for energy harvesting is proposed.展开更多
Objective: To assess the associations between body mass index (BMI), waist circumference (WC), and cardiometabolic risk factors in young and middle-aged Chinese women. Methods: A total of 3011 women (1938 young women,...Objective: To assess the associations between body mass index (BMI), waist circumference (WC), and cardiometabolic risk factors in young and middle-aged Chinese women. Methods: A total of 3011 women (1938 young women, 1073 middle-aged women), who visited our health care center for a related health checkup, were eligible for study. BMI and WC were measured. The subjects were divided into normal and overweight/obesity groups based on BMI, and normal and abdominal obesity groups based on WC. Cardiometabolic variables included triglyceride (TG), high density lipoprotein cholesterol (HDL-C), fasting blood glucose (FBG), homeostasis model assessment of insulin resistance (HOMA-IR), and blood pressure (BP). Results: The prevalence of overweight/obesity was significantly higher in middle-aged women (32.4%) than in young women (12.0%). The prevalence of abdominal obesity was also higher in middle-aged women (60.3%) than in young women (36.2%). There were significant differences in the comparison of all related cardiometabolic variables between different BMI (or WC) categories in young and middle- aged women groups, respectively. After adjustment for age, partial correlation analysis indicated that both BMI and WC were correlated significantly with all related cardiometabolic variables. After adjustment for age and WC, although the correlation coefficient r′was attenuated, BMI was still correlated significantly with all related cardiometabolic variables in young and middle-aged women. After adjustment for age and BMI, partial correlation analysis showed that WC was correlated significantly with TG, FBG, HOMA-IR, and HDL-C in young women and significantly with TG, HOMA-IR, and HDL-C in middle-aged women. Conclusions: The prevalence of overweight/obesity and abdominal obesity was high in Chinese young and middle-aged women. BMI was a better predictor of cardiovascular disease and diabetes than WC in young and middle-aged women, and moreover, measurement of both WC and BMI may be a better predictor of cardiovascular disease and diabetes mellitus than BMI or WC alone.展开更多
Recently, the barrier coverage was proposed and received much attention in wireless sensor network (WSN), and the degree of the barrier coverage, one of the critical parameters of WSN, must be re-studied due to the di...Recently, the barrier coverage was proposed and received much attention in wireless sensor network (WSN), and the degree of the barrier coverage, one of the critical parameters of WSN, must be re-studied due to the difference between the barrier coverage and blanket coverage. In this paper, we propose two algorithms, namely, local tree based no-way and back (LTNWB) algorithm and sensor minimum cut sets (SMCS) algorithm, for the opened and closed belt regions to determine the degree of the barrier coverage of WSN. Our main objective is to minimize the complexity of these algorithms. For the opened belt region, both algorithms work well, and for the closed belt region, they will still come into existence while some restricted conditions are taken into consideration. Finally, the simulation results demonstrate the feasibility of the proposed algorithms.展开更多
文摘Energy harvesting is an area of substantial and increasing research attention, and vibration-based devices dominate this research. The primary goal of most researchers is producing maximum electrical output from the harvester systems. However, there have been little metrological considerations for circumstances under which the energy harvester devices are characterized. This makes comparison of different device prototypes very difficult. It is the focus of this paper to highlight the need for metrological considerations to energy harvesting so that a universal metric can be developed. An attempt is also made to discuss the critical parameters that are essential in establishing an international standard on vibration-based energy harvesting. Finally, a simple standard for energy harvesting is proposed.
文摘Objective: To assess the associations between body mass index (BMI), waist circumference (WC), and cardiometabolic risk factors in young and middle-aged Chinese women. Methods: A total of 3011 women (1938 young women, 1073 middle-aged women), who visited our health care center for a related health checkup, were eligible for study. BMI and WC were measured. The subjects were divided into normal and overweight/obesity groups based on BMI, and normal and abdominal obesity groups based on WC. Cardiometabolic variables included triglyceride (TG), high density lipoprotein cholesterol (HDL-C), fasting blood glucose (FBG), homeostasis model assessment of insulin resistance (HOMA-IR), and blood pressure (BP). Results: The prevalence of overweight/obesity was significantly higher in middle-aged women (32.4%) than in young women (12.0%). The prevalence of abdominal obesity was also higher in middle-aged women (60.3%) than in young women (36.2%). There were significant differences in the comparison of all related cardiometabolic variables between different BMI (or WC) categories in young and middle- aged women groups, respectively. After adjustment for age, partial correlation analysis indicated that both BMI and WC were correlated significantly with all related cardiometabolic variables. After adjustment for age and WC, although the correlation coefficient r′was attenuated, BMI was still correlated significantly with all related cardiometabolic variables in young and middle-aged women. After adjustment for age and BMI, partial correlation analysis showed that WC was correlated significantly with TG, FBG, HOMA-IR, and HDL-C in young women and significantly with TG, HOMA-IR, and HDL-C in middle-aged women. Conclusions: The prevalence of overweight/obesity and abdominal obesity was high in Chinese young and middle-aged women. BMI was a better predictor of cardiovascular disease and diabetes than WC in young and middle-aged women, and moreover, measurement of both WC and BMI may be a better predictor of cardiovascular disease and diabetes mellitus than BMI or WC alone.
文摘Recently, the barrier coverage was proposed and received much attention in wireless sensor network (WSN), and the degree of the barrier coverage, one of the critical parameters of WSN, must be re-studied due to the difference between the barrier coverage and blanket coverage. In this paper, we propose two algorithms, namely, local tree based no-way and back (LTNWB) algorithm and sensor minimum cut sets (SMCS) algorithm, for the opened and closed belt regions to determine the degree of the barrier coverage of WSN. Our main objective is to minimize the complexity of these algorithms. For the opened belt region, both algorithms work well, and for the closed belt region, they will still come into existence while some restricted conditions are taken into consideration. Finally, the simulation results demonstrate the feasibility of the proposed algorithms.
