隨著微型製造技術、通訊技術、電池與網際網路科技的迅速發展，使得微小型的感測器(sensor node)具備了感應、無線通訊與資料處理的能力，並促進了無線感測網路的蓬勃發展。基本上，一個無線感測網路是由多個感測器及一個資料收集中心(sink)所組合而成的，在此網路架構中，感應器負責觀測所在環境中的事件，並以無線傳輸的方式將所觀測到的各項資訊傳送至資料收集中心，當感測器與資料收集中心無直接相互溝通的能力時，感測器就必須仰賴多跳躍(multi-hop)技術來完成資料傳遞的工作。而資料收集中心則必須處理、分析所收到之訊息並做出適當的決策動作。
綜觀上述的無線感測器環境，有幾個問題是我們需要探討的：首先，資料收集中心需處理、分析各項資訊，並決定相關的決策結果與行動，因此資料收集中心在此網路架構中扮演著重要的角色。然而，當此資料中心發生錯誤或損毀時，整個網路架構相關的資料分析、決策動作亦將隨之停擺。除此之外，當感測器未能與資料中心直接傳遞訊息時，雖可透過多跳躍技術傳遞相關訊息，但此技術將會產生一些額外的訊息傳遞時間，這對於一個講求時效性的環境，例如火災感應的環境來說，是較不適合的。最後，在網路中，每一個感測器可能會因為電力不足的問題，使其無法感應或發送訊息，亦或是遭到外力破壞，導致感測器損壞而發出錯誤訊息至資料收集中心，除此之外，感測器是透過無線傳輸的方式與其它感測器或資料收集中心聯繫，當其無線傳輸過程中遭到干擾或惡意破壞，皆有可能影響資訊傳遞的正確性。
為解決上述問題，在此我們將感測器分散於各個位於室內區域環境中，而位於同一區域之感測器皆具有其自主性，並結合分散式環境中著名的容錯演算法：協議問題技術，讓各區域內的感測器能自行感測事件並共同決議相關之決策或行動。
本論文將分別討論當傳輸媒介損毀、感測器損毀以及此兩種元件同時損毀的狀況下，每一個正常運行的感測器如何彼此合作而達成協議。換句話說，在此環境中，所有之感測事件、結果與最後之決策行為皆可由各個區域性內的感測器共同決定，而不再需要資料收集中心的協助，因此能解決資料收集中心單點錯誤的問題。再者，由於感測器已分散在各個較小的區域性環境中，在同一區域內的感測器可直接溝通，因此可減少多跳躍式方式所產生的訊息交換時間。

A traditional WSN is composed of several sensor nodes and a centralized sink. The sink analyzes data measured by the distributed sensor nodes and takes appropriate actions. A problem with this kind of architecture is that it may have a single-point of failure. Also, sensor nodes are not connected directly to the sink and must send data by hopping scheme through other sensor nodes. This means that it would take more time for the sink to collect data. Furthermore, in a WSN, faulty sensor nodes or noise may distort the message during transmission. An intruder may also alter the message maliciously. So far, there has been little research done on the design of robust WSN to overcome the single-point of failure problem and environmental interference. In this thesis, we propose a consensus problem algorithm based solution to enhance the accuracy of the detected result in an indoor autonomous local sensor network without a centralized sink. Under our scheme, there is no need to send the detected values to the sink. The solution can therefore reduce the transmission and routing time, allowing appropriate action to be made directly and quickly.

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