位点能量分布理论(Site energy distribution theory,SEDT)是一种从能量的角度去研究吸附机理的理论方法,它可以提供吸附剂表面位点的吸附能量以及对应的分布函数.因此SEDT在吸附能不均匀的吸附剂表面上的应用有着独特的优势.该理论在...位点能量分布理论(Site energy distribution theory,SEDT)是一种从能量的角度去研究吸附机理的理论方法,它可以提供吸附剂表面位点的吸附能量以及对应的分布函数.因此SEDT在吸附能不均匀的吸附剂表面上的应用有着独特的优势.该理论在化学化工领域的吸附剂材料上有着广泛的应用,尤其是在碳材料上有着较为深入的研究.土壤和沉积物是环境中重要的天然吸附剂,有着比碳材料表面更复杂的特性,因此已有研究将SEDT用于土壤和沉积物对污染物的吸附过程中.然而现有的研究在污染物对象的选取以及该理论的应用方式上存在一定的局限性.鉴于SEDT在土壤和沉积物上的应用潜能及重要意义,本文详细地介绍了SEDT的主要内容,并综述了SEDT在国内外吸附领域的应用研究进展,旨在将化学化工领域已有的SEDT应用与讨论方式迁移到环境领域中,最后对SEDT在土壤和沉积物上更深入的应用以及SEDT自身的发展提出了展望.展开更多
The key techniques in indoor positioning based on visible light communication and the state of the art of this research were surveyed. First, the significance of indoor positioning based on visible light communication...The key techniques in indoor positioning based on visible light communication and the state of the art of this research were surveyed. First, the significance of indoor positioning based on visible light communication from two aspects of the limitations of current indoor positioning technology and the advantages of visible light communication was discussed; And then, the main four technology of indoor positioning based on visible light communication were summarized and the triangulation of RSS method and the principle of image positioning were introduced in detail; Next, the performance characteristics of various typical algorithms were compared and analyzed; In the end, several suggestions on future research of indoor positioning based on visible light communication were given.展开更多
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
文摘位点能量分布理论(Site energy distribution theory,SEDT)是一种从能量的角度去研究吸附机理的理论方法,它可以提供吸附剂表面位点的吸附能量以及对应的分布函数.因此SEDT在吸附能不均匀的吸附剂表面上的应用有着独特的优势.该理论在化学化工领域的吸附剂材料上有着广泛的应用,尤其是在碳材料上有着较为深入的研究.土壤和沉积物是环境中重要的天然吸附剂,有着比碳材料表面更复杂的特性,因此已有研究将SEDT用于土壤和沉积物对污染物的吸附过程中.然而现有的研究在污染物对象的选取以及该理论的应用方式上存在一定的局限性.鉴于SEDT在土壤和沉积物上的应用潜能及重要意义,本文详细地介绍了SEDT的主要内容,并综述了SEDT在国内外吸附领域的应用研究进展,旨在将化学化工领域已有的SEDT应用与讨论方式迁移到环境领域中,最后对SEDT在土壤和沉积物上更深入的应用以及SEDT自身的发展提出了展望.
基金supported by National Nature Science Foundation of China (No. 61373124)supported by China Scholarship Funds (2014CB3033)
文摘The key techniques in indoor positioning based on visible light communication and the state of the art of this research were surveyed. First, the significance of indoor positioning based on visible light communication from two aspects of the limitations of current indoor positioning technology and the advantages of visible light communication was discussed; And then, the main four technology of indoor positioning based on visible light communication were summarized and the triangulation of RSS method and the principle of image positioning were introduced in detail; Next, the performance characteristics of various typical algorithms were compared and analyzed; In the end, several suggestions on future research of indoor positioning based on visible light communication were given.
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.
