近幾年來，由於社會大眾的健康觀念興起，對城市中的空氣品質逐漸受到重視，因此，能夠即時取得空氣品質的資訊也變得相當重要，另一方面，因為智慧型手機與行動網路的普及，民眾參與資料蒐集變得更加容易，也能實現即時空氣品質監測。然而，城市中的車流量相當龐大，現代的車輛也能攜帶多樣化的感測器，這樣的情境相當符合無線感測網路的特性，也因此，本論文考量結合車載感測網路來協助蒐集市區的空氣品質，然而，城市中的汙染物濃度往往會因為氣候或是排放量等因素，造成部分區域汙染濃度變化呈現劇烈或平緩的現象，此外，街道中的車輛會因交通號誌或會車等事件，而改變車輛的行為模式；考量到上述現象，本論文在上述車載感測網路的架構下，制定動態調變車輛蒐集行為機制，以濃度變化與車輛行為等資訊調變車輛之蒐集速率，將蒐集的行為鎖定在濃度變化劇烈的區域，並減少平緩區域的蒐集量，藉以維持監測的準確度並減少不必要的浪費；我們透過模擬在真實街道上的車輛行為與汙染氣體的擴散模式，來分析並驗證所提出的方法，實驗數據顯示，我們的方法可以在維持監測準確度的前提下，有效地降低成本。

Obtaining real-time air quality information in urban area has received considerable attention in recent years due to the awareness of the health care. Nowadays, it is easier for public to participate in collecting data and monitoring air quality anytime by smartphones and cellular networks. Also, the massive traffic in city and functional sensors carried by vehicles help develop vehicular sensor networks. Therefore, we consider using vehicular sensor network to assist in collecting air quality information. However, the pollutant concentration would vary dramatically or smoothly, depending on the weather and the quantity of pollutant. On the other hand, vehicles’ movement would be affected by traffic signs or events on the road. Motivated by the above two observations, this paper proposes a data-collection adjustment method for vehicular sensor networks. In order to ensure the monitor quality and reduce the unnecessary data collection, our method asks vehicles to collect more data in the area with dramatically varies concentration, and allows them to collect less data in the area with smoothly varies concentration. Finally, we use the simulations of the vehicle behavior and the dispersion model of pollutant to analyze and verify our method. The result shows that our method can not only effectively reduce the cost but also ensure the monitoring quality.

論文審定書 i
誌謝 ii
摘要 iii
Abstract iv
目錄 v
圖次 vii
表次 ix
第一章 導論 1
1.1 簡介 1
1.2 研究動機 2
1.3 研究貢獻及章節架構 3
第二章 相關文獻探討 4
2.1 固定式裝置之監測方法 4
2.2 移動式裝置之監測方法 5
2.3 空氣品質指數 6
2.4 都市交通車流模型 7
2.5 汙染氣體擴散模型 9
第三章 問題定義 11
第四章 研究方法 13
4.1 調變階段：動態網格調變 14
4.1.1 網格切割與合併 14
4.1.2 數據蒐集速率設置 18
4.2 蒐集階段：車輛蒐集行為設置 20
4.2.1 車輛參與機制 21
4.2.2 數據封包格式設定 22
第五章 模擬與分析 28
5.1 模擬環境與參數設定 28
5.2 車流數目對方法之影響 30
5.3 道路限速對方法之影響 33
5.4 受測區域面積對方法之影響 35
5.5 汙染源數量對方法之影響 37
第六章 結論與未來研究方向 39
參考文獻 40

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