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標題: 一個以圖形節點中介值為指標之移動式 Wi-Fi熱點偵測技術
A Study on Detecting Portable Wi-Fi Hotspots from Wi-Fi Trace Logs using Node Centrality Measure
作者: Cheng-Yuan Hsu
關鍵字: Portable Wi-Fi Hotspot
Betweenness Centrality
Mobile Application
Positioning Service
引用: 參考文獻 [1] 張建彥、吳宗修、王森豐、郭明仁,交叉路口高齡者與孩童步行速率之調查與分析,都市交通半年刊,2010. [2] Y. Chon, E. Talipov, and H. Cha, 'Autonomous Management of Everyday Places for a Personalized Location Provider,' IEEE SMC, 2012. [3] P. Prasithsangaree, P. Krishnamurthy, and P. K. Chrysanthis, 'On Indoor Position Location with Wireless Lans,' in PIMRC, 2002. [4] Y. Chon, N. D. Lane, F. Li, H. Cha, and F. Zhao, 'Automatically Characterizing Places with Opportunistic Crowdsensing Using Smartphones,' in UbiComp, 2012. [5] O. Dousse, J. Eberle, and M. Mertens, 'Place Learning Via Direct WiFi Fingerprint Clustering,' in MDM, 2012. [6] Y. Jiang, X. Pan, K. Li, Q. Lv, R. P. Dick, M. Hannigan, and L. Shang, 'ARIEL: Automatic Wi-Fi Based Room Fingerprinting for Indoor Localization,' in UbiComp,2012. [7] D. H. Kim, Y. Kim, D. Estrin, and M. B. Srivastava, 'SensLoc: Sensing Everyday Places and Paths Using Less Energy,' in SenSys,2010. [8] T. M. T. Do, and G. P. Daniel, 'The Places of Our Lives: Visiting Patterns and Automatic Labeling from Longitudinal Smartphone Data,' IEEE Transactions on Mobile Computing, 2014. [9] D. H. Kim, K. Han, and D. Estrin, 'Employing User Feedback for Semantic Location Services,' in UbiComp, 2011. [10] H. Wang, S. Sen, A. Elgohary, M. Farid, M. Youssef, and R. R. Choudhury, 'No Need to War-Drive: Unsupervised Indoor Localization,' in MobiSys, 2012. [11] L. C. Freeman, 'Centrality In Social Networks Conceptual Clarification,' Social Networks Volume 1, Issue 3, pp.215-239, 1979.
摘要: The user positioning system plays a critical role in the application of smart gadgets. In the past, most of the user positioning functions rely on the GPS. However, using the GPS for user positioning comes along with the problems of high power consumption and the difficulty of positioning indoor locations. Therefore, in recent years, an increasing number of researchers begins to utilize Wi-Fi hotspot for user positioning. The existing Wi-Fi hotspot positioning technology is assumed that Wi-Fi hotspot is installed at a fixed location. However, in the real world, not all Wi-Fi hotspots are fixed installed. With the popularity of mobile device and the demands of internet surfing, it is a commonplace that the people share their internet connection via mobile devices to their friends. The mobile devices sharing internet connection becomes a kind of portable Wi-Fi hotspot. The portable Wi-Fi hotspots become interference for the existing Wi-Fi based positioning technology. As a result, precisely detecting the portable Wi-Fi hotspot turns out to be an important issue. To detect portable Wi-Fi hotspot, in this study, we propose to model the problem by a graph model, and then employ the Betweenness Centrality measure as a referential standard to detect the portable Wi-Fi hotspot. With the graph model view, we propose schemes to address the problem of detecting portable Wi-Fi hotspot problem. The experiments with real Wi-Fi trace logs are conducted and the experiment results demonstrate the effectiveness of the proposed schemes.
使用者定位功能於智慧型行動裝置的應用中,扮演著極為重要之角色。過去使用者定位功能主要仰賴著全球定位系統(GPS, Global Positioning System)。但由於使用GPS系統來進行定位,一直存在著高耗電量與室內無法定位之問題。因此近年來,若干研究投入利用Wi-Fi熱點來做為定位系統的參考依據。然而現有的Wi-Fi熱點定位技術主要基於將Wi-Fi熱點視為固定裝設之假設,但這項假設在現實環境中不全為真,例如:隨著使用行動上網人口的日益增加,利用行動裝置進行移動式Wi-Fi熱點分享功能來分享網際網路的情形也不為少見。有鑑於移動式Wi-Fi熱點會對現有之Wi-Fi熱點定位技術,視Wi-Fi熱點為固定安裝之假設產生極大的干擾。因此,如何精準地偵測出移動式Wi-Fi熱點,避免其造成後續Wi-Fi定位技術上之干擾,便成為一關鍵且值得研究之議題。本研究中我們將移動式Wi-Fi熱點偵測之問題,轉化為一圖形模型(Graph Model),並提出使用圖形節點中介值(Betweenness Centrality)為參考指標,來偵測移動式Wi-Fi熱點。但由於受到相鄰近的Wi-Fi熱點,容易產生彼此間訊號重疊的干擾,進而影響了本研究中對移動式Wi-Fi熱點的偵測結果。對此,我們從實際的觀察中發現,由於Wi-Fi熱點受到訊號發射距離的限制,因此在相鄰近的時間點內,同時可被觀察到的Wi-Fi熱點,彼此間將不會距離彼此太遠的距離。我們針對此項特性,利用設定一個固定的時間區間值,將位於時間區間值內所能觀察到的Wi-Fi熱點,依時間先後順序逐次予以滑動合併,並將此合併後的結果重新轉化成另一新的圖形模型,再次依中介值指標的計算結果來偵測移動式Wi-Fi熱點。經實驗後證明,本方法確實可解決因Wi-Fi熱點訊號相互重疊時對研究結果產生的干擾,並可有效地偵測出移動式Wi-Fi熱點。
其他識別: U0005-2708201514215200
文章公開時間: 10000-01-01
Appears in Collections:資訊科學與工程學系所



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