無線感測網路(Wireless Sensor Network 或 WSNs)的存活期取決於參與監控之感測器剩餘電量，然而由於部點不均、環境外力影響或電量耗盡會導致監控網路中產生覆蓋空洞，影響感測的精確性、通訊的效率以及減短無線感測網路的存活期，所以如何確保監控區域的覆蓋性是一重要研究議題。本論文擬提出一具電量控制的覆蓋技術，透過感測節點間分散式地改變感測節點感應的電量，調整感測範圍的大小，同時兼顧網路連通性以及完整覆蓋整個監控區域之能力。除此之外，本論文考慮感測器範圍為可調式，依據各個感測器的電量不同，透過具權重式的Voronoi Diagram來劃分感測器應負責的感測區域，以達到電量平衡及全區覆蓋的目的，並對感測網路中每個節點進行電量平衡的工作，期望讓每個感測節點能在相同時間內死亡，藉以提升整個網路最大生命週期。

Wireless sensor networks (WSNs) have a wide range of potential applications including the measure of earthquake, light, or temperature in environment monitoring application or the detection of enemy or chemical gas in military detection application. How to fully cover a given interested region is one of the most important issues in WSNs. In a WSN, some coverage holes might exist due to unbalance sensor deployment or energy exhaustion. Hence, the sensing accuracy and communication efficiency will also be influenced due to the existing coverage holes. This proposal presents a plan for power-controlled coverage mechanism for a given WSN. The proposal aims to develop a distributed mechanism to adjust the sensing rage of each sensor to ensure that the whole network is full covered. Besides, this research also takes remaining energy into consideration to balance the remaining energy of each sensor and hence extend the maximum network lifetime.

目錄
目錄	III
圖目錄	V
表目錄	VIII	
第一章、緒論	1
第二章、相關背景與研究	4
2.1 覆蓋問題介紹	4
2.2 Area Coverage研究成果	5
2.3 Voronoi Diagram	     10
2.4 電量消耗問題	12
第三章、網路環境與問題描述	15
3.1 網路環境	15
3.2 問題描述	16
第四章、以可調式感測範圍發展具電量感知的技術	19
4.1 基本概念	19
4.2覆蓋技術細節論述	      21
4.2.1建構權重式Voronoi Diagram(Phase I)	21
4.2.2 消除感測器重疊的感測區域(Phase II)	26
4.2.3 延長網路的生命週期(Phase III)	33
4.3 特性與優勢	38
第五章、模擬與分析	    39
5.1 模擬環境	39
5.2 模擬結果的分析與比較	40
第六章、結論	44
參考文獻	45
附錄-英文論文	47

圖目錄	
圖(一) Full Area Coverage的議題中，最少醒來感測器數量的輪流醒睡機制 6
圖(二) 計算感測器的Sensor and Communication Range以填補覆蓋空洞 7
圖(三) Mobile Sensor填補覆蓋空洞與電量接力 8
圖(四) 運用虛擬力的原理，解決覆蓋空洞問題 8
圖(五) Voronoi Diagram 10
圖(六) 以Voronoi Diagram劃分責任區，但感測器剩餘電量不均11
圖(七) 剩餘電量較小之感測器會因電量耗盡而提早死亡，使整個網路存活期縮短 11
圖(八) 建立Delaunay三角形並找出其重心，以其來確保區域完整覆蓋 12
圖(九) 剩餘電量較小之感測器會因電量耗盡而提早死亡，使整個網路存活期縮短 13
圖(十) 建置Delaunay三角形，並透過每個感測器調整感測範圍的大小來確保全區覆蓋 14
圖(十一) 整個網路會因電量極度不平均而提早死亡 14
圖(十二) 感測器的數量少於完整覆蓋所需的最小數量時 16
圖(十三) 感測器電量耗費部份後 16
圖(十四) 電量感知的覆蓋技術流程圖 20
圖(十五) 畫Weighted Voronoi Cell 21
圖(十六) Weighted Voronoi Diagram	22
圖(十七) 使用中垂線來劃分各個感測器所需負責的覆蓋區域 23
圖(十八) 根據剩餘電量來劃分感測器與鄰居劃分各自負責的區域 23
圖(十九) 監測區域出現許多Special Areas(SA) 23
圖(二十) Division Point(DP) 24
圖(二十一) 監測場景使用Division Point分割Special Area 25
圖(二十二) 選取一個距離自己最遠的頂點vfarthest調整感測範圍大小 26
圖(二十三) 感測器感測區域重疊 27
圖(二十四) 覆蓋區域重疊過多而導致感測節點電量無謂的浪費 27
圖(二十五) Si的感測半徑ri大於 28
圖(二十六) Si的感測半徑ri縮小至 28
圖(二十七) Coverage Intersection Point(CIP) 29
圖(二十八) Fixed Sensor 30
圖(二十九) Adjustable Sensor 31
圖(三十) 斜線區域為可減少的感測區域 31
圖(三十一) 監測區域消除重疊的感測區域之後的狀態	32
圖(三十二) 電量較高的感測器幫助電量較低的感測器覆蓋區域	33
圖(三十三) Second Coverage Intersection Point(SCIP) 34
圖(三十四) 感測半徑縮小於SCIP，空洞將會複雜化 35
圖(三十五) 最小生命週期	36
圖(三十六) 覆蓋空洞 37
圖(三十七) Phase I、II 和 III的整體網路生命週期比較 41
圖(三十八) AE 和 DT的整體網路生命週期比較 41
圖(三十九) 綜合比較 42
圖(四十) 最大感測半徑之感測器數量 43
圖(四十一) 平均感測半徑	43

表目錄
表(一) 各符號定義 15
表(二) 環境參數	39

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