物聯網（IOT）近年來被視為半導體產業的下一波推力。在未來，人們預期會有大量新興的互聯裝置，感測環境數據，根據外界刺激反應，進而提供各式各樣的服務。然而，由於全球經濟規模以及能源產出在近未來並不會有大幅的成長，人們所預期的物聯網成長也將被總成本及能源消耗所限制。由於成本與系統可靠度高度相關，我們使用新提出的共生系統模型設計具備修復資源的可靠物聯網系統來解決這個問題。在共生系統模型的基礎上，我們提出了同儕修復機制，使得一個具有修復資源的物聯網裝置不僅可以修復自己，還可以修復其鄰近的裝置。在使用共生系統模型與同儕修復機制下，我們試著評估及分析一個物聯網系統的可靠度和成本。實驗結果顯示，在不替換損壞裝置的情況下，相較於只有自我修復機制的物聯網系統，具備同儕修復的系統可以有50%更長的壽命。在長期的運作中，當我們需要定期以人力替換損壞的裝置以維持系統的功能及可靠度時，具備同儕修復的系統可以達到更低的運作成本。此外，我們提出了一個激進的替換策略，更換正常運作中但是可能即將損壞的裝置，使得運作成本可以進一步的大幅降低。在每個裝置僅具備一個修復資源的條件下，具備同儕修復的系統運作成本為僅有自我修復的系統的50%，為沒有修復機制系統的10%。

Internet of Things (IOT) has been regarded as the next market driver in the semiconductor industry in recent years. People are expecting large amount of emerging connected devices sensing the environment, reacting to stimulus and providing various kinds of service. However, as the economic scale and energy is not likely to growth dramatically in the near future, the expected growth of IOT devices and systems will be constrained by total cost and energy consumption. As cost is highly related to reliability, we address the problem by adopting a newly proposed symbiotic system (SS) model, in designing IOT system with repair resources. We also propose a peer-assisted repair mechanism (peer-repair), which allows an IOT device to repair its faulty neighboring devices. With the model and mechanism, we are able to evaluate the reliability and cost of the entire IOT system. Experimental result shows that without replacing faulty devices in the system, the lifetime of the peer-repair enhanced system can be extended by 50%, as compared with the one using only self-repair. In addition, when considering manual replacement in long-term operation, the peer-repair system is able to achieve much lower cost. With a repair resource, the cost of systems with peer-repair is reduced to 50% of those with self-repair, and 10% of those without repair.

摘要 i
Abstract ii
Table of Content iii
List of Figures v
List of Tables vii
Chapter 1 Introduction 1
1.1 Motivation 1
1.2 Related Works 1
1.3 Approach and Result 3
1.4 Organization 3
Chapter 2 IOT Device Network Model 5
2.1 Symbiotic System Model 5
2.2 IOT Device Model 6
2.3 IOT Network Model 7
2.4 Cost Model 8
Chapter 3 Symbiotic System Simulator 9
3.1 Finite-State-Machine Base Class 9
3.2 IOT Device Network Simulator Overview 11
3.3 IOT Device 12
3.4 IOT Network 15
3.5 Hazard Generator 16
3.6 Simulation Monitor 16
Chapter 4 Experimental Results 18
4.1 Peer-Repair vs. Self-Repair 19
4.2 Number of Peers 21
4.3 Working Threshold 22
4.4 Repair Rate 24
4.5 Replacement Policy 26
4.6 Replacement Cost 27
4.7 Operation Cost 28
Chapter 5 Conclusion and Future Work 31
Bibliography 33

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