Approved for public release, distribution is unlimited / With the rapidly growing demand for portable devices such as laptops, handheld computers and Personal Digital Assistants (PDAs) with wireless networking capabilities, the need for reliable wireless data network communication has also increased. Just like in mobile voice communication, users demand uninterrupted, secure wireless data communication as they move from place to place. Mobile IP satisfies some of these demands - it enables mobile devices with fixed IP addresses to be permanently reachable even as their point of attachment to the network changes. This allows for routing of data packets to and from the mobile device irrespective of its location on the network. While uninterrupted data flow can be achieved with Mobile IP, it introduces additional security vulnerabilities, including data privacy, data integrity and authentication. The goal of this thesis is to investigate such vulnerabilities and explore implementations to overcome them. / Civilian, National Science Foundation

Approved for public release, distribution unlimited / Adopting Extensible Markup Language (XML) and Hypertext Transfer Protocol (HTTP) are key steps to accommodate the evolution of Internet technologies. While HTTP is already a proven standard communication protocol responsible for the rapid expansion of the World Wide Web, XML provides general mechanisms for determining validatable documents and addresses several deficiencies of HTML regarding diverse document structure and content. XML and HTTP together provide many of the essential capabilities associated with database engines. The Modeling, Virtual Environments and Simulation (MOVES) Institute of the Naval Postgraduate School (NPS) is continuing to build a database of 3D tactical scenarios and using X3D and VRML tools. The configuration parameters and statistical results of these scenarios are XML documents. For a better understanding and usability of these results by the end users, a Webbased application stores and manipulates these XML document. This thesis develops a server-side application that can store, serve, and annotate tactical scenarios for X3D operational visualization and anti-terrorist training by using XML and HTTP technologies. The experimental demonstration for this work is the prototypical Anti-Terrorism/Force Protection (AT/FP) simulation model developed by Lieutenant James W. Harney, USN, using Extensible 3D Graphics (X3D)/ Virtual Reality Modeling Language (VRML) models. / Captain, Tunisian Army

Approved for public release; distribution is unlimited / Simple Network Management Protocol (SNMP) allows users of network equipment (i.e. Network Administrators) to remotely query the state of any device being tested for system load, utilization and configuration. Windows NT, Windows 2000 and Windows XP Professional are all equipped with SNMP service so that an SNMP manager can communicate with an SNMP agent running on a wireless 802.11b client. However the rest of Windows operating systems, including Windows CE and a Pocket PC, have to run third party proxy SNMP agents in order to be recognized by an SNMP management application. This thesis describes an implementation of a Pocket PC SNMP agent for two Pocket PC mobile devices accessing a wired network via an 802.11b wireless link. As a result of the implementation performed in this thesis, an SNMP manager can wirelessly communicate with a Pocket PC client. However, other results found that only some of the commercially available SNMP managers are able to access the mobile SNMP client and its management information base, due to incompatible implementations of the server and client software. / Lieutenant, Royal Thai Air Force

by Sze Ho Pong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 50-[53]). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Related Work --- p.3 / Chapter 1.2 --- Contributions of the Thesis --- p.3 / Chapter 1.3 --- Organization of the Thesis --- p.4 / Chapter 2 --- Background --- p.5 / Chapter 2.1 --- Best-effort Internet - The Lossy Network --- p.5 / Chapter 2.2 --- Effects of Packet Loss on Streamed Video --- p.7 / Chapter 2.3 --- Loss Recovery Schemes in Video Streaming --- p.8 / Chapter 3 --- Comparison of Two Packet-Loss Detection Schemes --- p.10 / Chapter 3.1 --- Gap Detection (GD) --- p.12 / Chapter 3.2 --- Time-Out (TO) Detection --- p.14 / Chapter 3.3 --- Mathematical Comparison --- p.17 / Chapter 4 --- The Combined Loss-Detection Algorithm --- p.21 / Chapter 4.1 --- System Architecture --- p.22 / Chapter 4.2 --- Loss Detection and Recovery --- p.23 / Chapter 4.2.1 --- Detecting Data Packet Losses Transmitted for First Time --- p.24 / Chapter 4.2.2 --- Detecting Losses of Retransmitted Packet --- p.28 / Chapter 4.3 --- Buffering Techniques --- p.32 / Chapter 4.3.1 --- Determining Packet-Loss Rate in Presentation --- p.33 / Chapter 4.4 --- Mapping Packet-Loss Rate to Degradation of Video Quality --- p.38 / Chapter 5 --- Experimental Results and Analysis --- p.40 / Chapter 5.1 --- Experimental Setup --- p.40 / Chapter 5.2 --- Small Delay Jitter Environment --- p.42 / Chapter 5.3 --- Large Delay Jitter Environment --- p.44 / Chapter 5.3.1 --- Using Low Bit-Rate Stream --- p.44 / Chapter 5.3.2 --- Using High Bit-Rate Stream --- p.44 / Chapter 6 --- Conclusions and Future Work --- p.47 / Chapter 6.1 --- Conclusions --- p.47 / Chapter 6.2 --- Future Work --- p.49 / Bibliography --- p.50

by Yip Chung Sun Danny. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 52-54). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Organization of Thesis --- p.5 / Chapter Chapter 2 --- Background --- p.6 / Chapter 2.1 --- Speech Codec --- p.6 / Chapter 2.2 --- RTP/UDP/IP Header Compression --- p.7 / Chapter 2.2.1 --- Real-Time Transport Protocol --- p.7 / Chapter 2.2.2 --- RTP/UDP/IP Header Compression --- p.8 / Chapter Chapter 3 --- Scenario and Assumptions --- p.10 / Chapter Chapter 4 --- Asynchronous Time Division Multiplexing Scheme --- p.14 / Chapter 4.1 --- Basic Idea --- p.14 / Chapter 4.1.1 --- Bandwidth Efficiency Improvement --- p.16 / Chapter 4.1.2 --- Delay Reduction --- p.18 / Chapter 4.2 --- Header Compression --- p.19 / Chapter 4.2.1 --- Header Compression Process --- p.21 / Chapter 4.2.2 --- Context Mapping Table --- p.23 / Chapter 4.3 --- Protocol --- p.28 / Chapter 4.3.1 --- UNCOMPRESSED_RTP Mini-Header --- p.30 / Chapter 4.3.2 --- SYNCHRONIZATION Mini-header --- p.31 / Chapter 4.3.3 --- COMPRESSED´ؤRTP Mini-header --- p.32 / Chapter 4.4 --- Connection Establishment --- p.33 / Chapter 4.4.1 --- Addressing Phase --- p.34 / Chapter 4.4.2 --- Connection Phase --- p.36 / Chapter 4.5 --- Software Implementation --- p.38 / Chapter Chapter 5 --- Simulation Results --- p.39 / Chapter 5.1 --- Simulation Model --- p.39 / Chapter 5.2 --- Voice Source Model --- p.41 / Chapter 5.3 --- Simulation Results --- p.43 / Chapter 5.3.1 --- Network Utilization and Delay Performance --- p.43 / Chapter 5.3.2 --- Number of Supported Connections --- p.45 / Chapter Chapter 6 --- Conclusion and Future Work --- p.49 / Bibliography --- p.52

by Chan Ho Chow. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 65-67). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Background --- p.5 / Chapter 2.1. --- Packet Loss in the Internet --- p.5 / Chapter 2.2. --- Shared Internet --- p.7 / Chapter 2.3. --- Video Streaming --- p.10 / Chapter 2.4. --- Real-time video transmission criteria --- p.11 / Chapter 2.5. --- Existing Video Streaming Protocol --- p.13 / Chapter Chapter 3 --- Transmission Control Protocol (TCP) --- p.16 / Chapter Chapter 4 --- Variable-rate Streaming TCP (VarS-TCP) --- p.22 / Chapter 4.1. --- General Idea --- p.22 / Chapter 4.2. --- Assumptions --- p.25 / Chapter 4.3. --- VarS-TCP Algorithm --- p.26 / Chapter 4.3.1. --- Connection Initialization --- p.26 / Chapter 4.3.2. --- Normal Data Transfer --- p.27 / Chapter 4.4. --- Skipping packets in TCP --- p.32 / Chapter 4.4.1. --- Types of skipped packet --- p.32 / Chapter 4.4.2. --- Acknowledging skipped packets --- p.34 / Chapter 4.4.3. --- Maintaining Normal Data Flow --- p.35 / Chapter 4.4.4. --- Congestion Control --- p.37 / Chapter 4.4.5. --- Packets skipped by receiver --- p.41 / Chapter 4.5. --- Rebuffering --- p.44 / Chapter Chapter 5 --- Simulation Result --- p.45 / Chapter 5.1. --- Accumulating Data --- p.46 / Chapter 5.2. --- Delay Constraints --- p.48 / Chapter 5.3. --- Adapting network situation --- p.50 / Chapter 5.4. --- Sharing bandwidth with TCP --- p.52 / Chapter 5.5. --- Random Traffic --- p.58 / Chapter 5.6. --- Effect of packet skip threshold --- p.59 / Chapter 5.7. --- Effect of round-trip-time --- p.61 / Chapter Chapter 6 --- Conclusion and Future Works --- p.63 / Bibliography --- p.65

by Hung King Fai Kevin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 82-85 (2nd gp.)). / Abstracts in English and Chinese. / ACKNOWLEDGEMENT --- p.ii / ABSTRACT --- p.iii / 摘要 --- p.v / TABLE OF CONTENTS --- p.vi / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- OBJECTIVES --- p.1 / Chapter 1.2 --- NEED FOR PATIENT-MONITORING SYSTEM --- p.1 / Chapter 1.2.1 --- Aging Population --- p.1 / Chapter 1.2.2 --- Increasing Population with Heart Diseases --- p.2 / Chapter 1.3 --- ECG BASICS --- p.3 / Chapter 1.4 --- EXISITING ECG-MONITORING TECHNOLOGIES --- p.4 / Chapter 1.5 --- CHALLENGES IN PATIENT-MONITORING --- p.5 / Chapter 1.6 --- DEVELOPMENT OF AN ECG-MONITORING SYSTEM --- p.6 / Chapter 1.6.1 --- Overall Structure --- p.6 / Chapter 1.6.2 --- Considerations --- p.7 / Chapter CHAPTER 2 --- EMI FILTERS IN ECG ACQUISITION CIRCUIT --- p.8 / Chapter 2.1 --- OVERVIEW OF NOISE SOURCES IN ECG ACQUISITION --- p.8 / Chapter 2.1.1 --- Other Biopotentials --- p.8 / Chapter 2.1.2 --- Motion Artifact --- p.8 / Chapter 2.1.3 --- Power-line Interference --- p.10 / Chapter 2.1.4 --- High-Frequency Electromagnetic Interference --- p.15 / Chapter 2.2 --- EMI FILTERS --- p.16 / Chapter 2.2.1 --- Introduction to EMI Filters --- p.16 / Chapter 2.2.2 --- Types of EMI Filter --- p.17 / Chapter 2.2.3 --- EMI Filters in ECG Monitoring --- p.21 / Chapter 2.3 --- MODELING OF INTERFERENCE IN ECG-MONITORING SYSTEM --- p.22 / Chapter 2.3.1 --- Model and Parameters --- p.22 / Chapter 2.3.2 --- Method --- p.24 / Chapter 2.3.2 --- Results --- p.27 / Chapter 2.3.3 --- Discussion --- p.30 / Chapter 2.4 --- BUILDING AN ECG ACQUISITION CIRCUIT WITH EMI FILTERS --- p.30 / Chapter 2.4.1 --- Purpose --- p.30 / Chapter 2.4.2 --- Experimental Setup and Method --- p.30 / Chapter 2.4.3 --- Results --- p.32 / Chapter 2.4.4 --- Discussion --- p.46 / Chapter CHAPTER 3 --- ADAPTIVE FILTER --- p.48 / Chapter 3.1 --- OBJECTIVE --- p.48 / Chapter 3.2 --- INTRODUCTION TO ADAPTIVE FILTER --- p.48 / Chapter 3.3 --- METHOD --- p.50 / Chapter 3.4 --- RESULTS --- p.52 / Chapter 3.5 --- DISCUSSION --- p.57 / Chapter CHAPTER 4 --- WAP-BASED TELEMEDICINE APPLICATIONS --- p.59 / Chapter 4.1 --- INTRODUCTION TO TELEMEDICINE --- p.59 / Chapter 4.2 --- INTRODUCTION TO WAP --- p.59 / Chapter 4.3 --- WAP APPLICATIONS --- p.60 / Chapter 4.4 --- SYSTEM IMPLEMENTATION --- p.63 / Chapter 4.4.1 --- Overall Structure --- p.63 / Chapter 4.4.2 --- Relational Database --- p.63 / Chapter 4.4.3 --- Program Flow --- p.64 / Chapter 4.4.4 --- ECG Browsing and Feature Extraction --- p.70 / Chapter 4.5 --- EMULATION --- p.72 / Chapter 4.6 --- EXPERIENCE WITH WAP PHONE --- p.74 / Chapter 4.7 --- DISCUSSION AND CONCLUSION --- p.75 / Chapter CHAPTER 5: --- CONCLUSION AND FUTURE WORK --- p.77 / Chapter 5.1 --- CONCLUSION --- p.77 / Chapter 5.2 --- FUTURE WORK --- p.77 / Chapter 5.3 --- MARKET ANALYSIS --- p.79 / BIBLIOGRAPHY --- p.80

Hua Cunqing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 53-56). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Congestion Control in the IP Network --- p.1 / Chapter 1.2 --- Quality of Service in the IP network --- p.2 / Chapter 1.3 --- Structure of Thesis --- p.3 / Chapter 2 --- Background --- p.4 / Chapter 2.1 --- TCP and Congestion Control --- p.4 / Chapter 2.1.1 --- Slow Start --- p.4 / Chapter 2.1.2 --- Congestion Avoidance --- p.5 / Chapter 2.1.3 --- "Fast Retransmit, Fast Recovery and Timeout" --- p.5 / Chapter 2.2 --- Active Queue Management --- p.7 / Chapter 2.3 --- Integrated Services and Differentiated Services --- p.8 / Chapter 3 --- The Fairness of TCP Vegas in Networks with Multiple Congested Gate- ways --- p.10 / Chapter 3.1 --- Introduction --- p.10 / Chapter 3.2 --- TCP Vegas and related works --- p.11 / Chapter 3.3 --- Analysis --- p.13 / Chapter 3.4 --- Simulation Results --- p.15 / Chapter 3.4.1 --- Throughput for different number of active cross connections --- p.16 / Chapter 3.4.2 --- Throughput for different number of flows in each connection --- p.17 / Chapter 3.4.3 --- Multiple congestion vs Single congestion --- p.17 / Chapter 3.5 --- Summary --- p.19 / Chapter 4 --- The Joint Congestion Control for TCP/IP Networks --- p.21 / Chapter 4.1 --- Background --- p.21 / Chapter 4.2 --- The Joint Congestion Control --- p.23 / Chapter 4.2.1 --- Path Load Reduction Factor --- p.23 / Chapter 4.2.2 --- The Congestion Control Algorithm --- p.24 / Chapter 4.2.3 --- Probing Interval --- p.26 / Chapter 4.2.4 --- Parameter Setting --- p.26 / Chapter 4.2.5 --- Encoding of R --- p.27 / Chapter 4.3 --- Simulation Results --- p.28 / Chapter 4.3.1 --- Congestion Window Behavior --- p.28 / Chapter 4.3.2 --- Throughput Stability --- p.31 / Chapter 4.3.3 --- Packet Loss Ratio --- p.31 / Chapter 4.3.4 --- Fairness Index --- p.32 / Chapter 4.3.5 --- Fairness in Multiple-hop Network --- p.32 / Chapter 4.3.6 --- Parameter Sensitivity --- p.33 / Chapter 4.3.7 --- Interaction between JCC and Reno flows --- p.35 / Chapter 4.4 --- Summary --- p.35 / Chapter 5 --- S-WTP : Shifted Waiting Time Priority Scheduling for Delay Differ- entiated Services --- p.37 / Chapter 5.1 --- Introduction --- p.37 / Chapter 5.2 --- Scheduling Algorithms for Delay Differentiated Services --- p.38 / Chapter 5.3 --- Shifted Waiting Time Priority Scheduling --- p.41 / Chapter 5.3.1 --- Local Update --- p.42 / Chapter 5.3.2 --- Global Update --- p.42 / Chapter 5.3.3 --- Computational overhead --- p.42 / Chapter 5.4 --- Simulation Results --- p.43 / Chapter 5.4.1 --- Microscopic View of Individual Packet Delay of S-WTP and WTP --- p.43 / Chapter 5.4.2 --- Delay Ratios in Different Timescales --- p.44 / Chapter 5.4.3 --- Effects of aggregate traffic and class load distribution on delay ratio --- p.44 / Chapter 5.4.4 --- Delay Ratios with More Classes --- p.48 / Chapter 5.5 --- Summary --- p.48 / Chapter 6 --- Conclusions --- p.50 / Chapter 6.1 --- Congestion Control --- p.50 / Chapter 6.2 --- Quality of Service Provision --- p.51 / Chapter 6.3 --- Final Remarks --- p.51

by Pan Jiao Feng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 89-93). / Abstract also in Chinese. / Abstract --- p.i / Acknowledgments --- p.v / List of Tables --- p.x / List of Figures --- p.xi / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Graph definitions --- p.2 / Chapter 1.2 --- The S box graph --- p.2 / Chapter 1.3 --- The file transfer graph --- p.4 / Chapter 1.4 --- "(g, f)-factor and (g, f)-factorization" --- p.5 / Chapter 1.5 --- Thesis contributions --- p.6 / Chapter 1.6 --- Organization of the thesis --- p.7 / Chapter Chapter 2. --- On the Optimal Four-way Switch Box Routing Structures of FPGA Greedy Routing Architectures --- p.8 / Chapter 2.1 --- Introduction --- p.9 / Chapter 2.1.1 --- FPGA model and S box model --- p.9 / Chapter 2.1.2 --- FPGA routing --- p.10 / Chapter 2.1.3 --- Problem formulation --- p.10 / Chapter 2.2 --- Definitions and terminology --- p.12 / Chapter 2.2.1 --- General terminology --- p.12 / Chapter 2.2.2 --- Graph definitions --- p.15 / Chapter 2.2.3 --- The S box graph --- p.15 / Chapter 2.3 --- Properties of the S box graph and side-to-side graphs --- p.16 / Chapter 2.3.1 --- On the properties of the S box graph --- p.16 / Chapter 2.3.2 --- The properties of side-to-side graphs --- p.19 / Chapter 2.4 --- Conversion of the four-way FPGA routing problem --- p.23 / Chapter 2.4.1 --- Conversion of the S box model --- p.24 / Chapter 2.4.2 --- Conversion of the DAAA model --- p.26 / Chapter 2.4.3 --- Conversion of the DADA model --- p.27 / Chapter 2.4.4 --- Conversion of the DDDA model --- p.28 / Chapter 2.5 --- Low bounds of routing switches --- p.28 / Chapter 2.5.1 --- The lower bound of the DAAA model --- p.29 / Chapter 2.5.2 --- The lower bound of the DADA model --- p.30 / Chapter 2.5.3 --- The lower bound of the DDDA model --- p.31 / Chapter 2.6 --- Optimal structure of one-side predetermined four-way FPGA routing --- p.32 / Chapter 2.7 --- Optimal structures of two-side and three-side predetermined four-way FPGA routing --- p.45 / Chapter 2.7.1 --- Optimal structure of two-side predetermined four-way FPGA routing --- p.46 / Chapter 2.7.2 --- Optimal structure of three-side predetermined four-way FPGA routing --- p.47 / Chapter 2.8 --- Conclusion --- p.49 / Appendix --- p.50 / Chapter Chapter 3. --- "Application of (0, f)-Factorization on the Scheduling of File Transfers" --- p.53 / Chapter 3.1 --- Introduction --- p.53 / Chapter 3.1.1 --- "(0,f)-factorization" --- p.54 / Chapter 3.1.2 --- File transfer model and its graph --- p.54 / Chapter 3.1.3 --- Previous results --- p.56 / Chapter 3.1.4 --- Our results and outline of the chapter --- p.56 / Chapter 3.2 --- NP-completeness --- p.57 / Chapter 3.3 --- Some lemmas --- p.58 / Chapter 3.4 --- Bounds of file transfer graphs --- p.59 / Chapter 3.5 --- Comparison --- p.62 / Chapter 3.6 --- Conclusion --- p.68 / Chapter Chapter 4. --- "Decomposition Graphs into (g,f)-Factors" --- p.69 / Chapter 4.1 --- Introduction --- p.69 / Chapter 4.1.1 --- "(g,f)-factors and (g,f)-factorizations" --- p.69 / Chapter 4.1.2 --- Previous work --- p.70 / Chapter 4.1.3 --- Our results --- p.72 / Chapter 4.2 --- Proof of Theorem 2 --- p.73 / Chapter 4.3 --- Proof of Theorem 3 --- p.79 / Chapter 4.4 --- Proof of Theorem 4 --- p.80 / Chapter 4.5 --- Related previous results --- p.82 / Chapter 4.6 --- Conclusion --- p.84 / Chapter Chapter 5. --- Conclusion --- p.85 / Chapter 5.1 --- About graph-based approaches --- p.85 / Chapter 5.2 --- FPGA routing --- p.87 / Chapter 5.3 --- The scheduling of file transfer --- p.88 / Bibliography --- p.89 / Vita --- p.94

This thesis looks in depth at telephony server clusters, the modern switchboards at the core of a packet-based telephony service. The most widely used de facto standard protocols for telecommunications are the Session Initiation Protocol (SIP) and the Real Time Protocol (RTP). SIP is a signaling protocol used to establish, maintain, and tear down communication channel between two or more parties. RTP is a media delivery protocol that allows packets to carry digitized voice, video, or text. SIP telephony server clusters that provide communications services, such as an emergency calling service, must be scalable and highly available. We evaluate existing commercial and open source telephony server clusters to see how they differ in scalability and high availability. We also investigate how a scalable SIP server cluster can be built on a cloud computing platform. Elasticity of resources is an attractive property for SIP server clusters because it allows the cluster to grow or shrink organically based on traffic load. However, simply deploying existing clusters to cloud computing platforms is not good enough to take full advantage of elasticity. We explore the design and implementation of clusters that scale in real-time. The database tier of our cluster was modified to use a scalable key-value store so that both the SIP proxy tier and the database tier can scale separately. Load monitoring and reactive threshold-based scaling logic is presented and evaluated. Server clusters also need to reduce processing latency. Otherwise, subscribers experience low quality of service such as delayed call establishment, dropped calls, and inadequate media quality. Cloud computing platforms do not guarantee latency on virtual machines due to resource contention on the same physical host. These extra latencies from resource contention are temporary in nature. Therefore, we propose and evaluate a mechanism that temporarily distributes more incoming calls to responsive SIP proxies, based on measurements of the processing delay in proxies. Availability of SIP server clusters is also a challenge on platforms where a node may fail anytime. We investigated how single component failures in a cluster can lead to a complete system outage. We found that for single component failures, simply having redundant components of the same type are enough to mask those failures. However, for client-facing components, smarter clients and DNS resolvers are necessary. Throughout the thesis, a prototype SIP proxy cluster is re-used, with variations in the architecture or configuration, to demonstrate and address issues mentioned above. This allows us to tie all of our approaches for different issues into one coherent system that is dynamically scalable, is responsive despite latency varations of virtual machines, and is tolerant of single component failures in cloud platforms.