Recent rapid rise of indoor location based services for smartphones has further increased the importance of precise localization of Wi-Fi Access Point(AP).However,most existing AP localization algorithms either exhibi...Recent rapid rise of indoor location based services for smartphones has further increased the importance of precise localization of Wi-Fi Access Point(AP).However,most existing AP localization algorithms either exhibit high errors or need specialized hardware in practical scenarios.In this paper,we propose a novel RSSI gradient-based AP localization algorithm.It consists of the following three major steps:firstly,it uses the local received signal strength variations to estimate the direction(minus gradient) of AP,then employs a direction clustering method to identify and filter measurement outliers,and finally adopts triangulation method to localize AP with the selected gradient directions.Experimental results demonstrate that the average localization error of our proposed algorithm is less than 2meters,far outperforming that of the weighted centroid approach.展开更多
Our survey indicates that rural people＇s satisfaction with medical service in the countryside is currently low. Intermediate variables of comments on medical institutions, medical staff and medicine directly influenc...Our survey indicates that rural people＇s satisfaction with medical service in the countryside is currently low. Intermediate variables of comments on medical institutions, medical staff and medicine directly influence their satisfaction with rural medical service. Among initial variables, except for age, legion, occupation and family income which also directly influence overall satisfaction, factors like education, primary type of illness among family members and diagnostic procedure and treatment afterwards have all indirect impact on overall satisfaction.展开更多
基金This work was supported in part by the National Natural Science Foundation of China，the Major Projects of Ministry of Industry and Information Technology，the National High Technology Research and Development Program of China
文摘Recent rapid rise of indoor location based services for smartphones has further increased the importance of precise localization of Wi-Fi Access Point(AP).However,most existing AP localization algorithms either exhibit high errors or need specialized hardware in practical scenarios.In this paper,we propose a novel RSSI gradient-based AP localization algorithm.It consists of the following three major steps:firstly,it uses the local received signal strength variations to estimate the direction(minus gradient) of AP,then employs a direction clustering method to identify and filter measurement outliers,and finally adopts triangulation method to localize AP with the selected gradient directions.Experimental results demonstrate that the average localization error of our proposed algorithm is less than 2meters,far outperforming that of the weighted centroid approach.
文摘Our survey indicates that rural people＇s satisfaction with medical service in the countryside is currently low. Intermediate variables of comments on medical institutions, medical staff and medicine directly influence their satisfaction with rural medical service. Among initial variables, except for age, legion, occupation and family income which also directly influence overall satisfaction, factors like education, primary type of illness among family members and diagnostic procedure and treatment afterwards have all indirect impact on overall satisfaction.
