This thesis examines the use of modelling approaches in Wireless Sensor Networks (WSNs) at node and sink to: reduce the amount of data that needs to be transmitted by each node and estimate sensor readings for locations where no data is available. First, to contextualise the contributions in this thesis, a framework for WSN monitoring applications (FieldMAP) is proposed. FieldMAP provides a structure for developing monitoring applications that advocates the use of modelling to improve the informational output of WSNs and goes beyond the sense- and-send approach commonly found in current, elded WSN applications. Rather than report raw sensor readings, FieldMAP advocates the use of a state vector to encapsulate the state of the phenomena sensed by the node. Second, the Spanish Inquisition Protocol (SIP) is presented. SIP reduces the amount of data that a sensor node must transmit by combining model-based ltering with Dual-Prediction approaches. SIP makes use of the state vector component of FieldMAP to form a simple predictive model that allows the sink to estimate sensor readings without requiring regular updates from the node. Transmissions are only made when the node detects that the predictive model no longer matches the evolving data stream. SIP is shown to produce up to a 99% reduction in the number of samples that require transmission on certain data sets using a simple linear approach and consistently outperforms comparable algorithms when used to compress the same data streams. Furthermore, the relationship between the user-specied error threshold and number of transmissions required to reconstruct a data set is explored, and a method to estimate the number of transmissions required to reconstruct the data stream at a given error threshold is proposed. When multiple parameters are sensed by a node, SIP allows them to be combined into a single state vector. This is demonstrated to further reduce the number of model updates required compared to processing each sensor stream individually. iii Third, a sink-based, on-line mechanism to impute missing sensor values and predict future readings from sensor nodes is developed and evaluated in the context of an on-line monitoring system for a Water Distribution System (WDS). The mechanism is based on a machine learning approach called Gaussian Process Regression (GPR), and is implemented such that it can exploit correlations between nodes in the network to improve predictions. An on-line windowing algorithm deals with data arriving out of order and provides a feedback mechanism to predict values when data is not received in a timely manner. A novel approach to create virtual sensors that allows a data stream to be predicted where no physical sensor is permanently deployed is developed from the on-line GPR mechanism. The use of correlation in prediction is shown to improve the accuracy of predicted data from 1.55 Pounds per Square Inch (PSI) Root Mean Squared Error (RMSE) to 0.01 PSI RMSE. In-situ evaluation of the Virtual Sensors approach over 36 days showed that an accuracy of 0:75 PSI was maintained. The protocols developed in this thesis present an opportunity to improve the output of environmental monitoring applications. By improving energy consumption, long-lived networks that collect detailed data are made possible. Furthermore, the utility of the data collected by these networks is increased by using it to improve coverage over areas where measurements are not taken or available.

Li Ning. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 52-55). / Abstracts in English and Chinese. / Acknowledgments --- p.ii / Abstract --- p.iii / 哲學碩士論文摘要 --- p.iv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Research Background --- p.2 / Chapter 1.2 --- Contributions of the Thesis --- p.5 / Chapter 1.3 --- Organization of the Thesis --- p.6 / Chapter Chapter 2 --- Properties of OVSF Codes --- p.7 / Chapter 2.1 --- Tree-Structured Generation of OVSF Codes --- p.7 / Chapter 2.2 --- OVSF Codes Assignment --- p.10 / Chapter Chapter 3 --- Support Delayable Traffic in Wireless Networks --- p.14 / Chapter 3.1 --- System Model --- p.15 / Chapter 3.2 --- Scheduling Algorithm with Burst Adaptation --- p.17 / Chapter 3.3 --- Performance Analysis --- p.22 / Chapter 3.4 --- Simulation Results --- p.24 / Chapter Chapter 4 --- Allocate OVSF Codes with Joint Design --- p.30 / Chapter 4.1 --- Combine Number of Active Users and Error-Control Coding Scheme --- p.31 / Chapter 4.1.1 --- System Model --- p.31 / Chapter 4.1.2 --- Scheduling Algorithm Description --- p.33 / Chapter 4.1.3 --- Simulation Results --- p.35 / Chapter 4.2 --- Combine Power Adaptation and Error-Control Coding Scheme --- p.39 / Chapter 4.2.1 --- System Model --- p.39 / Chapter 4.2.2 --- Scheduling Algorithm Description --- p.41 / Chapter 4.2.3 --- Simulation Results --- p.44 / Chapter Chapter 5 --- Conclusion --- p.50 / Bibliography --- p.52

Ngai Cheuk Han. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 110-117). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background Study --- p.5 / Chapter 2.1 --- Mobile Ad Hoc Networks --- p.5 / Chapter 2.1.1 --- Definition --- p.5 / Chapter 2.1.2 --- Characteristics --- p.5 / Chapter 2.1.3 --- Applications --- p.6 / Chapter 2.1.4 --- Standards --- p.7 / Chapter 2.1.5 --- Routing Protocols --- p.8 / Chapter 2.2 --- Security in Mobile Ad Hoc Networks --- p.11 / Chapter 2.2.1 --- Vulnerabilities --- p.11 / Chapter 2.2.2 --- Motivation for the Attacks --- p.12 / Chapter 2.2.3 --- Types of Attacks --- p.13 / Chapter 2.3 --- Cryptography --- p.13 / Chapter 2.3.1 --- Cryptographic goals --- p.13 / Chapter 2.3.2 --- Symmetric-key encryption --- p.14 / Chapter 2.3.3 --- Asymmetric-key encryption --- p.14 / Chapter 2.3.4 --- Digital Signatures --- p.15 / Chapter 2.3.5 --- Digital Certificates --- p.15 / Chapter 2.3.6 --- Certificate Authority --- p.16 / Chapter 2.4 --- Literature Review --- p.17 / Chapter 3 --- Related Work --- p.23 / Chapter 4 --- Architecture and Models --- p.26 / Chapter 4.1 --- Architecture of the Authentication Service --- p.26 / Chapter 4.2 --- The Network Model --- p.28 / Chapter 4.2.1 --- Clustering-Based Structure --- p.31 / Chapter 4.2.2 --- Clusterhead Selection Criteria and Role --- p.33 / Chapter 4.3 --- The Trust Model --- p.37 / Chapter 4.3.1 --- Direct TVust --- p.40 / Chapter 4.3.2 --- Recommendation Trust --- p.41 / Chapter 4.3.3 --- Deriving Direct Trust --- p.41 / Chapter 5 --- Trust- and Clustering-Based Authentication Service --- p.43 / Chapter 5.1 --- Clustering Structure Formation and Maintenance --- p.43 / Chapter 5.1.1 --- Clustering Structure Formation --- p.43 / Chapter 5.1.2 --- Network Maintenance --- p.45 / Chapter 5.2 --- Security Operations --- p.50 / Chapter 5.2.1 --- Public Key Certification --- p.51 / Chapter 5.2.2 --- Identification of Malicious Nodes --- p.55 / Chapter 5.2.3 --- Trust Value Update --- p.58 / Chapter 5.3 --- Special Scenarios --- p.60 / Chapter 5.3.1 --- Join the network --- p.60 / Chapter 5.3.2 --- Move to another cluster --- p.61 / Chapter 5.3.3 --- Not Enough Introducer --- p.62 / Chapter 6 --- Simulations and Results --- p.65 / Chapter 6.1 --- Authentication Service Based on Trust and Network Mod- els --- p.65 / Chapter 6.1.1 --- Experiments Set-Up --- p.65 / Chapter 6.1.2 --- Simulation Results --- p.67 / Chapter 6.2 --- Clusters Formation and Maintenance --- p.85 / Chapter 6.2.1 --- Experiments Set-Up --- p.85 / Chapter 6.2.2 --- Simulation Results --- p.86 / Chapter 6.3 --- Authentication Service Based on Trust and Network Mod- els with Clusters Formation and Maintenance --- p.91 / Chapter 6.3.1 --- Experiments Set-Up --- p.91 / Chapter 6.3.2 --- Simulation Results --- p.94 / Chapter 7 --- Conclusion --- p.108 / Bibliography --- p.117

Wong Tsz-Chun Stanley. / Thesis submitted in: July 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 58-61). / Abstracts in English and Chinese. / 摘要 --- p.III / ACKNOWLEDGEMENT --- p.IV / LIST OF FIGURES --- p.VIII / Chapter CHAPTER 1 --- INTRODUCTION --- p.2 / Chapter 1.1 --- Introduction --- p.2 / Chapter 1.2 --- Organization of the Thesis --- p.6 / Chapter CHAPTER 2 --- BACKGROUND STUDIES --- p.7 / Chapter 2.1 --- Overview of IEEE 802.11 --- p.7 / Chapter 2.3 --- 802.11b Network Type --- p.10 / Chapter 2.4 --- IEEE 802.11 MAC overview --- p.12 / Chapter 2.4.1 --- Distributed Coordination Function (DCF) / Point Coordination Function (PCF) --- p.13 / Chapter 2.4. --- Request-to-Send (RTS) / Clear-to-Send (CTS) --- p.14 / Chapter CHAPTER 3 --- QUEUE MANAGEMENT IN ACCESS POINTS --- p.16 / Chapter 3.1 --- Introduction --- p.16 / Chapter 3.2 --- Packet Delay Variation in Access Points --- p.17 / Chapter 3.2 --- Simulations Settings and Configuration --- p.19 / Chapter 3.2.1 --- Mobile Networking in NS2 --- p.19 / Chapter 3.2.2 --- Input Parameter of Shadowing Radio Propagation model --- p.22 / Chapter 3.2.3 --- Configuration of the simulation --- p.25 / Chapter CHAPTER 4 --- PERFORMANCE ANALYSIS OF 802.11B DOWNLINKS --- p.30 / Chapter 4.1 --- Introduction --- p.30 / Chapter 4.5 --- Assumptions of the analysis --- p.31 / Chapter 4.3 --- Proposed Queue Management in Access Point --- p.32 / Chapter 4.4 --- Channel error modeling --- p.34 / Chapter 4.5 --- The analytical model of downlinks --- p.35 / Chapter 4.6 --- Performance Calculation --- p.37 / Chapter 4.4 --- Simulation Result --- p.41 / Chapter 4.4.1 --- Extension of NS2 --- p.42 / Chapter 4.4.2 --- Configuration of the simulation --- p.44 / Chapter CHAPTER 5 --- RESOURCE ASSIGNMENT IN ACCESS POINTS --- p.48 / Chapter 5.1 --- Introduction --- p.48 / Chapter 5.2 --- Packet Delay Balancing --- p.49 / Chapter 5.2 --- Simulation Result --- p.51 / Chapter CHAPTER 6 --- CONCLUSION --- p.56 / BIBLIOGRAPHY --- p.58

Liu Haiping. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 78-82). / Abstracts in English and Chinese. / Acknowledgments --- p.i / Abstract --- p.ii / Table of Contents --- p.vi / List of Figures --- p.vii / List of Tables --- p.ix / Chapter Chapter I --- Introduction to Wireless LAN --- p.1 / Chapter 1.1 --- Wireless LAN Netwrok Architecture --- p.2 / Chapter 1.2 --- IEEE 802.11 protocol family --- p.4 / Chapter 1.3 --- The Major factors influencing the System Performance --- p.7 / Chapter 1.4 --- Research Objectives --- p.13 / Chapter 1.5 --- Overview --- p.13 / Chapter Chapter II --- The Major Deficiency of DCF and Motivation --- p.14 / Chapter 2.1 --- DCF --- p.15 / Chapter 2.2 --- The Major Deficiencies in the DCF --- p.20 / Chapter 2.3 --- Improvement directions --- p.24 / Chapter Chapter III --- Proposed MAC Protocol --- p.27 / Chapter 3.1 --- The Design Idea --- p.28 / Chapter 3.2 --- The Number of Active Nodes --- p.30 / Chapter 3.3 --- Optimizaition Method for CW --- p.32 / Chapter 3.4 --- CW and Counter value Updating --- p.35 / Chapter 3.5 --- Procedure Flow and Simulation Results --- p.37 / Chapter Chapter IV --- Advanced Proposed Protocol with QoS issues --- p.44 / Chapter 4.1 --- "QoS requirement, EDCF solution and others' work" --- p.45 / Chapter 4.2 --- Frame structure changes in the Advanced Proposed MAC Protocol --- p.47 / Chapter 4.3 --- Recursivley Balance Optimization Method for CW --- p.48 / Chapter 4.4 --- Decision Algorithm --- p.54 / Chapter 4.5 --- Model Validation and Simulation Results --- p.66 / Chapter Chapter V --- Further Discussion about CW design --- p.70 / Chapter 5.1 --- Influence of the ranges of CW --- p.71 / Chapter 5.2 --- Proposal for adjusting CW --- p.73 / Chapter Chapter VI --- Conclusion --- p.75 / Bibliography --- p.78

Chen, Darui. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 62-67). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.vii / List of Tables --- p.viii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Related Works --- p.2 / Chapter 1.3 --- Contributions --- p.6 / Chapter 1.4 --- Organization --- p.8 / Chapter Chapter 2 --- Preliminaries --- p.9 / Chapter 2.1 --- MAC Protocol in IEEE 802.11 WLANs --- p.9 / Chapter 2.1.1 --- IEEE 802.11 DCF --- p.9 / Chapter 2.1.2 --- Performance Anomaly of DCF --- p.11 / Chapter 2.2 --- Multi-Rate WLANs with Rate Adaptation --- p.12 / Chapter 2.2.1 --- PHY-Layer Rate Adaptation Model --- p.12 / Chapter 2.2.2 --- Two Typical WLANs with Rate Adaptation --- p.13 / Chapter Chapter 3 --- Performance Analysis and Evaluation of Multi-Rate IEEE802.11 WLANs --- p.15 / Chapter 3.1 --- Theoretical Analysis of Multi-Rate IEEE 802.11 WLANs --- p.15 / Chapter 3.1.1 --- Markov Chain Model for Backoff Process --- p.15 / Chapter 3.1.2 --- Saturation Throughput --- p.18 / Chapter 3.1.3 --- Theoretical Throughput Limit and Dynamic Backoff --- p.20 / Chapter 3.2 --- Performance Evaluation of Multi- Rate WLANs --- p.22 / Chapter 3.2.1 --- Model Validation --- p.22 / Chapter 3.2.2 --- Theoretical Throughput Limit --- p.24 / Chapter Chapter 4 --- Rate-aware DCF Protocol --- p.30 / Chapter 4.1 --- Proposed R-DCF Protocol --- p.30 / Chapter 4.2 --- Theoretical Analysis of R-DCF --- p.34 / Chapter 4.2.1 --- Markov Chain Model for Backoff Process --- p.34 / Chapter 4.2.2 --- Saturation Throughput --- p.36 / Chapter 4.2.3 --- Simplified Models --- p.39 / Chapter 4.3 --- Performance Evaluation --- p.41 / Chapter 4.3.1 --- Model Validation --- p.41 / Chapter 4.3.2 --- R-DCF with Homogeneous Users --- p.42 / Chapter 4.3.3 --- R-DCF in Fixed-Rate WLANs --- p.49 / Chapter Chapter 5 --- Performance Enhancement of the R-DCF Protocol --- p.52 / Chapter 5.1 --- Maximizing Throughput of R-DCF --- p.52 / Chapter 5.2 --- Offline Adaptive Backoff Methods --- p.55 / Chapter Chapter 6 --- Conclusions --- p.60 / Bibliography --- p.62

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