Research indicates that learning how to regulate one’s emotions is critical to successful child development and is associated with adaptive social functioning and psychological adjustment (Dunn & Brown, 1994; Eisenberg, Fabes, Guthrie, & Reiser, 2000; Eisenberg, Fabes, & Murphy, 1996). Children’s emotion regulation abilities are thought to be influenced by both child (e.g., age, temperament) and parent characteristics (e.g., parenting behaviors, parental regulation; Eisenberg, Cumberland, & Spinrad, 1998). Resting heart rate variability (HRV) has emerged as a potentially important biomarker associated with emotion regulation (Porges, 2007; Thayer & Lane, 2000); however, there are still significant gaps in research. In particular, research indicates genetic correlates associated with HRV as well as an important role of parents in children’s emotion socialization, but research has yet to establish a strong link between parent and child HRV. Theoretically, parent and child HRV may be linked but only in specific contexts. For example, parent and child resting HRV may become more or less strongly related in the context of specific parenting behaviors, but research has yet to test this hypothesis. The present study examined the association between parenting behaviors and child resting HF-HRV (i.e., high frequency HRV), the links between parent and child resting HF-HRV, and potential moderating effects of parenting behaviors on the association in youth. Additional analyses examined associations between parent and child vagal regulation. Ninety-seven youth (11-17 years) and their caregivers (n = 81) participated in a physiological assessment and completed questionnaires assessing parenting behaviors. Results indicated that parent’s inconsistent discipline and corporal punishment were negatively associated with their child’s resting HF-HRV while positive parenting and parental involvement were positively associated. Furthermore, parent’s inconsistent discipline and parent’s involvement moderated the relationship between parent and child resting HF-HRV, such that in the context of high inconsistent discipline and high parental involvement, high parent resting HF-HRV was associated with low child resting HF-HRV. Findings add to the literature by providing evidence for the role of parenting behaviors in shaping the development of children’s HF-HRV and indicating that inconsistent discipline and parental involvement may affect the entrainment of HF-HRV in parents and their adolescent children.

<p>The mouth, throat, and face contain numerous muscles that participate in a large variety of orofacial behaviors. The jaw and tongue can move independently, and thus require a high degree of coordination among the muscles that move them to prevent self-injury. However, different orofacial behaviors require distinct patterns of coordination between these muscles. The method through which motor control circuitry might coordinate this activity has yet to be determined. Electrophysiological, immunohistochemical, and retrograde tracing studies have attempted to identify populations of premotor neurons which directly send information to orofacial motoneurons in an effort to identify sources of coordination. Yet these studies have not provided a complete picture of the population of neurons which monosynaptically connect to jaw and tongue motoneurons. Additionally, while many of these studies have suggested that premotor neurons projecting to multiple motor pools may play a role in coordination of orofacial muscles, no clear functional roles for these neurons in the coordination of natural orofacial movements has been identified.</p><p>In this dissertation, I took advantage of the recently developed monosynaptic rabies virus to trace the premotor circuits for the jaw-closing masseter muscle and tongue-protruding genioglossus muscle in the neonatal mouse, uncovering novel premotor inputs in the brainstem. Furthermore, these studies identified a set of neurons which form boutons onto motor neurons in multiple motor pools, providing a premotor substrate for orofacial coordination. I then combined a retrogradely traveling lentivirus with a split-intein mediated split-Cre recombinase system to isolate and manipulate a population of neurons which project to both left and right jaw-closing motor nuclei. I found that these bilaterally projecting neurons also innervate multiple other orofacial motor nuclei, premotor regions, and midbrain regions implicated in motor control. I anatomically and physiologically characterized these neurons and used optogenetic and chemicogenetic approaches to assess their role in natural jaw-closing behavior, specifically with reference to bilateral masseter muscle electromyogram (EMG) activity. These studies identified a population of bilaterally projecting neurons in the supratrigeminal nucleus as essential for maintenance of an appropriate level of masseter activation during natural chewing behavior in the freely moving mouse. Moreover, these studies uncovered two distinct roles of supratrigeminal bilaterally projecting neurons in bilaterally synchronized activation of masseter muscles, and active balancing of bilateral masseter muscle tone against an excitatory input. Together, these studies identify neurons which project to multiple motor nuclei as a mechanism by which the brain coordinates orofacial muscles during natural behavior.</p> / Dissertation

Introdução: Os motociclistas estão expostos tanto ao ruído ambiental como ao ruído gerado pela própria motocicleta. Tal exposição ao ruído pode provocar lesões na orelha interna, de modo que o registro das emissões otoacústicas por produto de distorção (EOAEPD) pode evidenciar as alterações de forma precoce. Objetivo: Verificar as variações das amplitudes das emissões otoacústicas evocadas por produto de distorção nos carteiros motociclistas normo-ouvintes de acordo com o tempo de exposição a ruído e analisar com trabalhadores normo-ouvintes não expostos a ruído ocupacional. Método: Foram avaliados 148 trabalhadores normo-ouvintes, distribuídos em quatro grupos: grupo I com exposição a ruído menor ou igual a dois anos, o grupo II com mais de dois anos e menos de cinco anos e o grupo III maior ou igual a cinco anos de exposição e o grupo IV não exposto ao ruído. Todos os trabalhadores selecionados foram submetidos ao registro das EOAEPD. Resultados: O grupo I apresentou amplitudes mais elevadas em 7250 Hz e 5128 Hz (p < 0,05), em comparação aos grupos II, III e IV. As menores respostas de amplitudes das EOAEPD ocorreram no grupo controle (grupo IV), sendo estatisticamente significativo nas freqüências entre 5128 Hz e 2588 Hz (p < 0,05). Conclusão: Os resultados sugerem que o monitoramento no início da exposição ao ruído ocupacional, por meio das emissões otoacústicas por produto de distorção, possibilita a detecção de alterações fisiopatológicas precoces da orelha interna por causa da presença de incrementos no registro da amplitude das EOAEPD. Estes incrementos precedem as alterações na audiometria tonal liminar e a ausência ou diminuição na amplitude das EOAEPD / Introduction: The motorcyclists are exposed as much to the environmental noise as to the noise generated by the own motorcycle. Such exposition to noise can provoke lesions in the internal ear and the registration of the distortion product otoacoustic emissions (DPOAEs) can evidence the alterations in a precocious way. Objective: To verify the variations of the amplitudes of the otoacoustic emissions evoked by distortion product in the postmen normo-listeners motorcyclists\' in agreement with the time of exposition to noise and to analyze with normo-listeners workers not exposed to occupational noise. Method: Hundred and forty-eight normo-listeners workers has been evaluated, distributed into four groups: group I - exposed to a smaller noise equivalent to two years noise-exposition; group II - equivalent to more than two years exposition and less than five years; group III - larger or equal to five years exposition; and the group IV - workers not exposed to noise being assigned to the control group. All selecioned workers were submitted to DPOAEs registration. Results: The group I presented higher amplitudes for 7250 Hz and 5128 Hz frequencies (p < 0.05), in comparison with the groups II, III and IV. The lowest values of DPOAEs amplitudes were observed in the control group (group IV), being statistically significantive for frequencies between 5128 Hz and 2588 Hz (p < 0.05). Conclusion: The results suggest that early monitoring of the exposition to occupational noise, through the distortion product otoacoustic emissions, makes possible the detection of precocious physiopathologic alterations of the internal ear due to the presence of increments in the amplitude registration of the DPOAEs. These increments precede the alterations in the preliminary tonal audiometry and the absence or decrease in the amplitude of the DPOAEs

Chan Kwun-chung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 71-73). / Abstracts in English and Chinese. / 摘要 --- p.II / ABSTRACT --- p.III / ACKNOWLEDGEMENT --- p.V / TABLE OF CONTENTS --- p.VI / LIST OF FIGURES --- p.X / LIST OF SYMBOLS --- p.XII / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Contributions --- p.3 / Chapter 1.2 --- Organization of the Thesis --- p.4 / Chapter 1.3 --- Publications --- p.5 / Chapter 2. --- RELATED WORKS --- p.6 / Chapter 2.1 --- Previous VOD System --- p.7 / Chapter 2.1.1 --- Service Model --- p.7 / Chapter 2.1.1.1 --- Unicast VOD --- p.7 / Chapter 2.1.1.2 --- Multicast VOD --- p.8 / Chapter 2.1.2 --- Architecture --- p.9 / Chapter 2.1.2.1 --- Centralized Architecture --- p.9 / Chapter 2.1.2.2 --- Distributed Architecture --- p.10 / Chapter 2.1.3 --- Interactive Function --- p.11 / Chapter 2.1.3.1 --- Limited Interactive Function --- p.11 / Chapter 2.1.3.2 --- Unlimited Interactive Function --- p.11 / Chapter 2.1.4 --- Split and Merge Operation --- p.12 / Chapter 2.1.4.1 --- SAM Scheme (Split and Merge) --- p.12 / Chapter 2.1.4.2 --- SRMDRU Scheme (Single Rate Multicast Double Rate Unicast) --- p.14 / Chapter 2.2 --- Previous Caching Algorithm --- p.15 / Chapter 2.2.1 --- LFU (Least Frequently Used) --- p.15 / Chapter 2.2.2 --- LRU (Least Recently Used) --- p.15 / Chapter 2.2.3 --- Media Stream Caching --- p.15 / Chapter 3. --- DESIGN OFA NOVEL VOD SYSTEM --- p.17 / Chapter 3.1 --- System Architecture --- p.18 / Chapter 3.1.1 --- Multicast Video Server Cluster (MVSC) --- p.19 / Chapter 3.1.2 --- Unicast Video Server Cluster (UVSC) --- p.20 / Chapter 3.1.3 --- Multicast Backbone Network (MBN) --- p.20 / Chapter 3.1.4 --- Local Distribution Network (LDN) --- p.21 / Chapter 3.1.5 --- Distributed Interactive Server (DIS) --- p.21 / Chapter 3.1.6 --- Distributed Proxy Server (DPS) --- p.22 / Chapter 3.1.7 --- Client Station (CS) --- p.22 / Chapter 3.2 --- Batched Multicast Transmission --- p.24 / Chapter 3.3 --- Split and Merge Operation --- p.26 / Chapter 3.4 --- Interactive Function --- p.31 / Chapter 3.4.1 --- Pause --- p.31 / Chapter 3.4.2 --- Slow Motion --- p.35 / Chapter 3.4.3 --- Various Speed Fast Forward / Fast Rewind (FF/REW) --- p.37 / Chapter 3.4.4 --- Jump Forward/Jump Backward (JF/JB) --- p.42 / Chapter 3.5 --- Performance Analysis --- p.46 / Chapter 3.5.1 --- Model --- p.46 / Chapter 3.5.2 --- System Parameters --- p.49 / Chapter 3.5.3 --- Results --- p.49 / Chapter 4. --- DESIGN OF A VIDEO PROXY SYSTEM --- p.57 / Chapter 4.1 --- Video Proxy System --- p.58 / Chapter 4.1.1 --- Priority Function --- p.59 / Chapter 4.1.2 --- Two-Stage Replacement Policy --- p.60 / Chapter 4.1.3 --- Caching Policy --- p.61 / Chapter 4.2 --- Performance Evaluation --- p.63 / Chapter 4.2.1 --- Simulation Environment --- p.63 / Chapter 4.2.2 --- Performance Metric --- p.64 / Chapter 4.2.3 --- Results --- p.64 / Chapter 5. --- CONCLUSION --- p.69 / BIBLIOGRAPHY --- p.71

by Ng Chi Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 64-65). / Abstracts in English and Chinese. / ABSTRACT --- p.I / ACKNOWLEDGEMENT --- p.II / TABLE OF CONTENTS --- p.III / LIST OF TABLES --- p.VI / LIST OF FIGURES --- p.VII / LIST OF ABBREVIATIONS --- p.X / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Overview --- p.1 / Chapter 1.2 --- Related works --- p.5 / Chapter 1.3 --- Organization of this Thesis --- p.6 / Chapter CHAPTER 2 --- BACKGROUND --- p.7 / Chapter 2.1 --- Introduction to VOD Systems --- p.7 / Chapter 2.1.1 --- Pure unicast VOD System --- p.8 / Chapter 2.1.2 --- Pure multicast VOD System --- p.9 / Chapter 2.1.3 --- Centralized VOD System --- p.9 / Chapter 2.1.4 --- Distributed VOD System --- p.10 / Chapter 2.1.5 --- Hybrid VOD System (DINA) --- p.11 / Chapter 2.1.6 --- Comparisons --- p.12 / Chapter 2.2 --- Interactive Functions --- p.14 / Chapter 2.2.1 --- Speedup --- p.14 / Chapter 2.2.2 --- Split and merge (I and S streams) --- p.14 / Chapter 2.2.3 --- Prerecord --- p.15 / Chapter 2.3 --- Error Recovery --- p.16 / Chapter 2.3.1 --- Pure FEC --- p.17 / Chapter 2.3.2 --- Pure ARQ --- p.17 / Chapter 2.3.3 --- Hybrid ARQ --- p.18 / Chapter 2.3.4 --- Rate-Compatible Punctured Convolutional Codes --- p.18 / Chapter CHAPTER 3 --- HYBRID MULTICAST-UNICAST VOD SYSTEM --- p.21 / Chapter 3.1 --- System Overview --- p.21 / Chapter 3.1.1 --- VSC (Video Server Cluster) --- p.22 / Chapter 3.1.2 --- DIS (Distributed Interactive Server) --- p.24 / Chapter 3.1.3 --- NAK (Negative Acknowledgement Server) --- p.25 / Chapter 3.1.4 --- CS (Client Stations) --- p.26 / Chapter 3.1.5 --- MBN (Multicast Backbone Network) --- p.27 / Chapter 3.1.6 --- LDN (Local Distribution Network) --- p.27 / Chapter 3.2 --- Interactive Functions --- p.28 / Chapter 3.2.1 --- Hybrid Multicast- Unicast --- p.28 / Chapter 3.2.2 --- Pause --- p.30 / Chapter 3.2.3 --- Slow Forward (SF) --- p.33 / Chapter 3.2.4 --- Slow Backward (SB) --- p.35 / Chapter 3.2.5 --- Fast Forward (FF) / Fast Backward (FB) --- p.38 / Chapter 3.2.6 --- Jump Forward (JF) / Jump Backward (JB) --- p.41 / Chapter 3.3 --- System Performance --- p.46 / Chapter 3.3.1 --- System Model --- p.46 / Chapter 3.3.2 --- Simulation Results --- p.47 / Chapter 3.3.3 --- Trade off --- p.53 / Chapter CHAPTER 4 --- DISTRIBUTED TYPE-II HARQ --- p.54 / Chapter 4.1 --- Algorithm Description --- p.54 / Chapter 4.1.1 --- Design details --- p.54 / Chapter 4.1.2 --- Simulation Results --- p.59 / Chapter CHAPTER 5 --- CONCLUSION --- p.62 / BIBLIOGRAPHY --- p.64

Leung Wai Tak. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 58-60). / Abstracts in English and Chinese. / Acknowledgement --- p.I / Abstract --- p.II / 摘要 --- p.III / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Related Works --- p.5 / Chapter 2.1 --- Previous Works --- p.5 / Chapter 2.2 --- Contributions of this Study --- p.7 / Chapter Chapter 3 --- Architecture --- p.9 / Chapter 3.1 --- Data Placement Policy --- p.10 / Chapter 3.2 --- Retrieval and Transmission Scheduling --- p.13 / Chapter 3.3 --- Fault Tolerance --- p.20 / Chapter Chapter 4 --- Performance Modeling --- p.22 / Chapter 4.1 --- Storage Requirement --- p.22 / Chapter 4.2 --- Network Bandwidth Requirement --- p.23 / Chapter 4.3 --- Buffer Requirement --- p.24 / Chapter 4.4 --- System Response Time --- p.27 / Chapter Chapter 5 --- System Reliability --- p.29 / Chapter 5.1 --- System Failure Model --- p.29 / Chapter 5.2 --- Minimum System Repair Capability --- p.32 / Chapter 5.3 --- Redundancy Configuration --- p.35 / Chapter Chapter 6 --- System Dimensioning --- p.37 / Chapter 6.1 --- Storage Capacity --- p.38 / Chapter 6.2 --- Network Capacity --- p.38 / Chapter 6.3 --- Disk Access Bandwidth --- p.39 / Chapter 6.4 --- Buffer Requirement --- p.41 / Chapter 6.5 --- System Response Time --- p.43 / Chapter Chapter 7 --- Multiple Parity Groups --- p.45 / Chapter 7.1 --- System Failure Model --- p.47 / Chapter 7.2 --- Buffer Requirement --- p.47 / Chapter 7.3 --- System Response Time --- p.49 / Chapter 7.4 --- Redundancy Configuration --- p.49 / Chapter 7.5 --- Scalability --- p.51 / Chapter Chapter 8 --- Conclusions and Future Works --- p.53 / Appendix --- p.55 / Chapter A. --- Derivation of the Artificial Admission Delay --- p.55 / Chapter B. --- Derivation of the Receiver Buffer Requirement --- p.56 / Bibliography --- p.58

To Ka Ki. / Thesis submitted in: August 2005. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 55-56). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abstract --- p.ii / 摘要 --- p.iii / Chapter Chapter 1 --- INTRODUCTION --- p.5 / Chapter Chapter 2 --- related WORKS --- p.12 / Chapter Chapter 3 --- Decentralization of Periodic Broadcasting --- p.16 / Chapter 3.1 --- Staggered Broadcasting --- p.16 / Chapter 3.2 --- Modified Staggered Broadcasting --- p.17 / Chapter Chapter 4 --- PEERS SYNCHRONIZATION --- p.21 / Chapter 4.1 --- Integrating PCS with Periodic Broadcasting --- p.22 / Chapter 4.2 --- Distributed PCS --- p.23 / Chapter Chapter 5 --- Performance Evaluations of Decentralized Periodic Broadcasting Architecture --- p.27 / Chapter 5.1 --- Sensitivity to Clock Drift --- p.28 / Chapter 5.2 --- System Dynamic Behavior --- p.30 / Chapter Chapter 6 --- P-NICE --- p.33 / Chapter 6.1 --- The Original NICE Protocol --- p.34 / Chapter 6.2 --- Parallel Overlay Architecture --- p.35 / Chapter 6.3 --- Control Overheads --- p.37 / Chapter Chapter 7 --- Performance Evaluations of P-NICE --- p.39 / Chapter 7.1 --- End-to-End Packet Delivery Ratio --- p.40 / Chapter 7.2 --- Utilization of Network Links --- p.41 / Chapter 7.3 --- Convergence Time of End-to-End Packet Delivery Ratio --- p.44 / Chapter 7.4 --- Effect of Number of Overlays --- p.45 / Chapter 7.5 --- End-to-End Data Delivery Delay --- p.47 / Chapter 7.6 --- Load Balance of Overlays --- p.47 / Chapter 7.7 --- Peers Reception Quality --- p.48 / Chapter 7.8 --- Control Overheads --- p.51 / Chapter Chapter 8 --- Conclusions --- p.53 / Bibliography --- p.55

此論文旨在探究對稱技巧在十二音創作概念與實踐之間的關係。前者抽象、後者具體。我先在第一章指出十二音系統内的對稱潛質，再在其後兩章分析對稱技巧在荀白克的《摩西與亞倫》及魏本的交響曲作品21第二樂章内的展現。荀白克“音樂意念及“發展變奏這兩個概念，在《摩西與亞倫》扮演着重要的角式，大大影響了作品内對稱的處理；而魏本對音樂的“一體性“及“可瞭解性“的堅持，亦決定了交響曲第二樂章中對稱的演譯。最後一章總括十二音作曲概念及實踐的關係，並展望日後的研究方向。 / Through an analytical study of Schoenberg’s Moses und Aron and Webern’s Symphony Op.21, second movement, my thesis aims at exploring a central issue in interpreting symmetry in twelve-tone music: the relationship between abstract conception and concrete realization. / In Chapter one, I endeavour to contextualize the uses of symmetry in twelve-tone music within contemporary theoretical perspectives. After defining my methodology, subsequent chapters are analytical examinations of two pieces. Chapter two explores how Schoenberg’s uses of symmetry in the opening of Moses und Aron might be closely associated with his conception of “idea and “developing variation. Chapter three considers the ways in which the symmetrical manifestations in Webern’s variation movement demonstrate his concern for “unity and “comprehensibility. After studying the two composers’ different symmetrical treatments Chapter 4 revisits the relationship between abstract conception and concrete realization in twelve-tone composition, and suggests implications for further research. / Detailed summary in vernacular field only. / Liu, Man Yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Abstract --- p.i / Abstract (Chinese) --- p.ii / Acknowledgements --- p.iii / List of Figures --- p.vi / List of Music Examples --- p.viii / Chapter Chapter 1 --- Abstract Conception versus Concrete Realization in Twelve-Tone Music --- p.1 / The Twelve-Tone System and its Symmetrical Potentials --- p.5 / Methodology, Selection of Pieces and Overview of Chapters --- p.8 / Chapter Chapter 2 --- Schoenberg’s "Idea" and Twelve-Tone Symmetry --- p.11 / Compositional Concerns / Row Design, Motive, Developing Variation and "Idea" --- p.14 / Moses und Aron: The Idea of God and the Twelve-Tone System --- p.20 / Pre-Compositional Plan / Schoenberg’s Divine Order --- p.28 / Compositional Practice / Realization of Unimaginable God --- p.33 / Realizations of Basic Set (P₉) and its Inversion (I₀) --- p.38 / Implications: Manifestation of Divine Order --- p.44 / First "Image": Musical Representation of the Row by Aron --- p.47 / Second "Image": Musical Representation of God by Aron in the Golden Calf scene --- p.53 / Schoenberg’s Allegory: Irreconcilability in Realizing "Idea" --- p.58 / Chapter Chapter 3 --- Webern’s Variationen and Twelve-Tone Symmetry --- p.64 / Compositional Concerns / Webern and Symmetry --- p.69 / Analytical Perspectives on Symphony Op.21, Second movement --- p.70 / Pre-Compositional Plan / Webern’s Statement on Symphony Op.21, Second movement --- p.73 / Compositional Practice / Thema --- p.77 / Variation I --- p.81 / Variation II --- p.85 / Variation III --- p.92 / Variation IV --- p.96 / Variation V --- p.101 / Variation VI --- p.105 / Variation VII --- p.107 / Coda --- p.110 / Summary --- p.112 / Chapter Chapter 4 --- Epilogue --- p.115 / Pre-Compositional Row Designs --- p.116 / Presentations of Rows in Their Music --- p.116 / Implications for Further Research --- p.119 / Select Bibliography --- p.121

點對點視頻點播是架構于互網上的熱門應用，旨在提供高質視頻服務。應用點對點技術的優勢在於，系統可用用戶資源以滿足其他用戶的觀賞需求，從而提高系統可擴展性并低運營成本。在該系統中存在以下關鍵設計因素。其一，在給定用戶資源時，如何以分佈式和動態性方法有效用這些資源；其二，考慮用戶自私性，如何激他們貢獻本地資源。 / 點對點視頻點播系統具有高動態性，非同步性及質性；相比文件共享系統還需大帶寬支持。這些特性使得解決以上技術問題充滿挑戰，因而激發我們的研究。我們試圖回答以下問題： / 如何確定存儲空間對各視頻的最佳分配比，從而最小化服務器負擔？ / 如何設計高效激機制使用戶於貢獻他們的本地資源？ / 我們首先關注最佳複製策。我們回答（1）在給定視頻條件下，如何確定視頻最佳複製比；（2）如何通過分佈式動態算法獲得這樣的最佳複製比。我們將視頻複製技術表達為最優化問題，显示傳統比複製法并非最優，而最優比應正比于文中定義的“欠缺帶寬。我們通過“被動替換算法與“主動推送算法以達到最優複製比，顯示我們的算法可使得服務器負擔大幅下以及服務質素顯著提高。 / 我們而後關注激機制設計。系統運營商需激用戶貢獻上載帶寬以傳輸據，以及本地存儲空間以存儲視頻。我們分解這個設計問題，并為它們逐一設計基於獎賞的激機制。（1）上載帶寬激。用戶根據貢獻帶寬受到獎賞。我們用博弈模型分析運營商與用戶之間的交互。我們推導出博弈均衡，分析系統高效性并研究多重博弈設定下的長期交互特性。（2）分佈存儲激。用戶根據緩存視頻受到獎賞。我們以優化模型刻畫視頻最佳獎賞價格。我們在漸進系統中推導出最優獎賞價格，然後將結果推廣至多種系統環境。 / 總而言之，該文從學建模、博弈分析、算法設計與性能評估等諸多角，解決點對點視頻點播系統中的資源獲取與分配策。 / Peer-to-Peer Video-on-Demand (P2P-VoD) is a popular Internet application which aims to provide a high quality video service to users. The advantage of using the P2P technology is that the system can utilize peers’ resources so as to satisfy other peers’ viewing requirement, thereby improving the system scalability and reducing the operating cost. There are two key design issues in P2P-VoDs. First, given the distributed resources of peers, what is the most efficient manner to utilize them in a distributed and dynamic fashion. Second, given the selfish nature of peers, how to incentivize the peers to contribute their local resources. / A P2P-VoD system is highly dynamic, asynchronous and heterogenous in nature. In addition, it requires a much higher bandwidth resource as compared with file sharing applications. These features make it challenging to solve the above technical problems, and hence motivate our work. In particular, we aim to answer: / How to determine the optimal ratios of storage space that should be assigned to each video, such that the content server’s workload can be minimized? / How to design effective and efficient incentive mechanisms so as to stimulate the peers to contribute their local resources? / We first focus on the optimal replication strategy. In particular, we answer (a) what is the optimal replication ratio of a video in terms of its popularity, and (b) how to achieve these optimal ratios in a distributed and dynamic fashion. We formulate the video replication as an optimization problem, and show that the conventional wisdom of using the proportional replication strategy is “sub-optimal“. The optimal replication ratios should be proportional to the “deficit bandwidth which we define in the thesis. We utilize “passive replacement policy“ and “active push policy“ to achieve the optimal replication ratios and show how to greatly reduce server’s workload and improve streaming quality via our distributed algorithms. / We next focus on incentive mechanisms design. The content providers need to incentivize the peers to contribute their upload capacity to delivery data, and local storage space to cache the videos. We decompose the problems and design reward-based incentive mechanisms for them respectively. (a) Incentivizing upload capacity. Each peer is rewarded based on its dedicated upload bandwidth. We analyze the interaction between a content provider and the peers using game theory. We derive a unique equilibrium, analyze the system efficiency and study the long term interactions under a repeated game setting. (b) Incentivizing distributed caching. Each peer is rewarded based on the videos they cache. We characterizes the optimal reward price using optimization. In particular, we first derive the optimal prices to obtain the desired amount of replicas in an asymptotic system, and then extend our results to adapt to various system environments. / To summarize, this thesis addresses the resource acquisition and allocation problems in P2P-VoD systems via mathematical modeling, game analysis, algorithms design and performance evaluations. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wu, Weijie. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 129-138). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract --- p.i / Acknowledgement --- p.v / Contents --- p.ix / List of Figures --- p.xiii / List of Tables --- p.xv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Peer-to-Peer Networks --- p.2 / Chapter 1.1.1 --- Classification of P2P Networks --- p.2 / Chapter 1.1.2 --- Applications of P2P Services --- p.4 / Chapter 1.2 --- P2P Video-on-Demand Systems --- p.4 / Chapter 1.2.1 --- General Architecture --- p.4 / Chapter 1.2.2 --- Key Advantages of P2P-VoDs --- p.6 / Chapter 1.3 --- Motivation --- p.7 / Chapter 1.4 --- Challenges --- p.8 / Chapter 1.5 --- Contributions --- p.10 / Chapter 1.6 --- A General System Model on P2P-VoDs --- p.12 / Chapter 1.7 --- Thesis Structure and Organization --- p.15 / Chapter 2 --- Optimal Replication Strategies in P2P-VoD Systems --- p.17 / Chapter 2.1 --- Chapter Overview --- p.17 / Chapter 2.2 --- Mathematical Model --- p.19 / Chapter 2.2.1 --- Basic System Assumptions and Peer Scheduling Policy --- p.19 / Chapter 2.2.2 --- Server’s Workload --- p.22 / Chapter 2.2.3 --- Discussion on Peer Operations --- p.26 / Chapter 2.2.4 --- Impact of Replication on Reducing the Server’s Workload --- p.27 / Chapter 2.3 --- Optimal Replication Ratios to Minimize Server’s Workload --- p.30 / Chapter 2.3.1 --- Operation Modes --- p.30 / Chapter 2.3.2 --- Characteristics of Deficit Bandwidth --- p.31 / Chapter 2.3.3 --- Characterizing the Optimal Replication Strategy --- p.34 / Chapter 2.3.4 --- Discussion on Heterogeneous Video Playback Rates --- p.36 / Chapter 2.4 --- Algorithms to Control Replication Ratios --- p.38 / Chapter 2.4.1 --- Passive Adjustment via Replacement Algorithm --- p.39 / Chapter 2.4.2 --- Active Adjustment via Push Strategy --- p.40 / Chapter 2.5 --- Performance Evaluation --- p.43 / Chapter 2.5.1 --- Performance of Replacement Algorithm --- p.43 / Chapter 2.5.2 --- Performance of Push Algorithm --- p.49 / Chapter 2.6 --- Chapter Summary --- p.51 / Chapter 3 --- Incentivizing Upload Capacity in P2P-VoD Systems --- p.53 / Chapter 3.1 --- Chapter Overview --- p.53 / Chapter 3.2 --- Peers’ Viewing Behavior and Reward-based Scheme --- p.55 / Chapter 3.2.1 --- Peers’ Viewing Behavior --- p.55 / Chapter 3.2.2 --- Reward-based Incentive Scheme --- p.57 / Chapter 3.3 --- Peers’ Contribution and Content Provider’s Cost --- p.58 / Chapter 3.3.1 --- Distribution of Peers in Different Video Segments --- p.58 / Chapter 3.3.2 --- Content Provider’s Upload Cost --- p.61 / Chapter 3.4 --- Game Theoretic Analysis on Incentive Scheme --- p.62 / Chapter 3.4.1 --- Stackelberg Game Model --- p.63 / Chapter 3.4.2 --- Existence and Uniqueness of Stackelberg Equilibrium --- p.64 / Chapter 3.4.3 --- Efficiency of Stackelberg Equilibrium --- p.67 / Chapter 3.4.4 --- General Reward Scheme --- p.72 / Chapter 3.4.5 --- Repeated Game Model --- p.73 / Chapter 3.5 --- Performance Evaluation --- p.77 / Chapter 3.6 --- Discussion on Practical Issues --- p.82 / Chapter 3.6.1 --- System Heterogeneity --- p.82 / Chapter 3.6.2 --- P2P-VoD System with Caching --- p.83 / Chapter 3.6.3 --- Cheating Prevention Guarantee --- p.84 / Chapter 3.7 --- Chapter Summary --- p.84 / Chapter 4 --- Incentivizing Distributed Caching in P2P-VoD Systems --- p.86 / Chapter 4.1 --- Chapter Overview --- p.86 / Chapter 4.2 --- Mathematical Model --- p.88 / Chapter 4.2.1 --- Preliminaries --- p.88 / Chapter 4.2.2 --- Peers’ Caching Behaviors --- p.91 / Chapter 4.2.3 --- Cache state distribution of peers of type m --- p.93 / Chapter 4.2.4 --- Cache State of the System --- p.95 / Chapter 4.2.5 --- Design Objectives of Pricing Schemes --- p.96 / Chapter 4.3 --- Asymptotic Analysis --- p.98 / Chapter 4.3.1 --- Cache State of Peers --- p.99 / Chapter 4.3.2 --- Conservative Pricing Problem --- p.102 / Chapter 4.3.3 --- Strategic Pricing Problem --- p.105 / Chapter 4.4 --- Generalizations and Extensions --- p.106 / Chapter 4.4.1 --- Viewing-Caching Decoupling --- p.107 / Chapter 4.4.2 --- General Sensitivity Model --- p.108 / Chapter 4.4.3 --- Non-Asymptotic System --- p.111 / Chapter 4.4.4 --- Pricing before Reaching the Steady State --- p.113 / Chapter 4.5 --- Performance Evaluation --- p.115 / Chapter 4.6 --- Chapter Summary --- p.119 / Chapter 5 --- Related Work --- p.120 / Chapter 5.1 --- Related Work on Replication Strategy --- p.120 / Chapter 5.2 --- Related Work on Incentive Mechanisms Design --- p.122 / Chapter 6 --- Conclusion and FutureWork --- p.125 / Chapter 6.1 --- Conclusion --- p.125 / Chapter 6.2 --- Future work --- p.126 / Chapter 6.2.1 --- Extensions for Various Practical Issues --- p.126 / Chapter 6.2.2 --- Incentive and Resource Allocation in Other Applications --- p.127 / Bibliography --- p.129

点对点网络是今年兴起的一个热门研究课题。 点对点网络有非常好的文件分发能力， 在传统的服务器客模式下， 服务器需要为每位客建立独立的链接。随着用的增加服务器的能力很快会变成瓶颈。点对点网络的优势在于能够通过下载相同内容的客共享交换内容， 从而利用每位客的上传带宽.基于这个特点,即使没有服务器的帮助， 只要客都无私的共享自己的内容， 点对点网络可以以非常高的效率分发大文件。 目前已经有很对研究成果是关于点对点网络的体系结构设计和网络协议设计。但随着文件大小和数量的快速增长， 客除了贡献带宽还会贡献一块硬盘来缓存一些自己并不感兴趣的内容来增加客间互相帮助的概率。尤其是视频点播应用的兴起给点对点网络的内容传输带来了新的挑战。例如如何能保证所有客流畅的点播视频，以及如何优化每个客缓存的内容来最小化服务器带宽需求。在本篇论文中， 我们将集中讨论点对点视频点播系统并解决以下问题： / 我们的目的是节省服务器带宽。一个最基本的问题是客节点的最优缓存替换策略问题。首先我们定义了完美请求调度策略，在这个调度策略的基础上提出RLB 缓存替换策略从而得到最小化服务器带宽。 / 第二个问题是不同的请求调度策略和最优的缓存替换策略之间是如何相互影响的。我们提出了FSBD 模型。通过研究每个客能发出的请求数目，我们恩能够比较不同的缓存替换策略和不同的调度策略之间的关系。 / 最后一个问题，我们研究了点对点视频点播系统在电影数量远远多于客数量的极端情况。在这种情况下， 由于客只能贡献非常少量的硬盘来缓存电影， 提供电影的覆盖和提高视频点播系统的吞吐量是一个互相矛盾的问题。两者不能同时达到最优。 / 除了以上的理论分析， 我们通过模拟试验来验证理论模型的正确性。 此外我们还提出了非常简单有效的分布式缓存替换策略用于实际系统的实现。相信以上的研究工作对于点对点视频系统的设计和实现有重要的帮助。 / Peer-to-Peer (P2P) systems become a hot research topic in recent years because of their excellent ability for content distribution. In traditional Client/Server(C/S) mode, the server must serve each user directly. The server capacity is the bottleneck when user population becomes large. The power of P2P network is to encourage peers to share common content with each other to offload server. The P2P systems distribute content very efficiently if all peers help others selflessly with minimal support from the server. There are many works dedicated to the architecture and protocol design for P2P systems. These works study how to organize peers to exchange content efficiently. As content size and content population are growing very fast today, P2P networks are used to support Video on Demand (VoD) streaming service. For VoD streaming, besides bandwidth, the peers are required to contribute storage to cache some content that they may not be interested in. The new challenges include how to guarantee that all peers can play video smoothly and how to cache the content at different peers to minimize server load . In this thesis, we study the following problems in a P2P VoD streaming system: / What the optimal movie replication strategy to minimize server load is. To study this problem, we first make an assumption to simplify the P2P service model. We assume that all peers follow a Perfect Fair Sharing (PFS) scheduling strategy. Based on this setup, we proposed Random Load Balance (RLB) algorithm to achieve minimum server load. We derive analytical bounds on the achieved server load. / Next, We observe that different P2P scheduling strategies lead to different “optimal replication strategies. Our second setup is to relax the assumption of perfect fair sharing scheduling by proposing a Fair Sharing with Bounded Degree (FSBD) model, parameterized by the maximum number of peers that can be used to serve a single request. PFS is a special case of FSBD. We compare different replication strategies for different in-degree bounds and see how and why different replication strategies are favored depending on the in-degree. / For the last problem, we let the movie population become large and assume that there is some skewness in movie popularity. Then peers can’t reduce server load and provide availability of all movies at the same time. In other words, peers must be selective in replicating sufficiently popular movies. It is a tradeoff between coverage of movies and streaming throughput provided by the P2P system. / Besides analysis, we also use simulation to validate our models. As a robust solution under different P2P service models, we proposed a simple adaptive movie replication algorithm with computation efficiency. Our study leads to several fundamental insights for the design of P2P VoD systems in practice. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Zhou, Yipeng. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 162-170). / Abstract also in Chinese. / Abstract --- p.i / Acknowledgement --- p.i / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.2 / Chapter 1.2 --- P2P VoD Streaming System --- p.6 / Chapter 1.3 --- Contribution --- p.11 / Chapter 1.4 --- Organization --- p.12 / Chapter 2 --- Model --- p.14 / Chapter 2.1 --- Assumptions and Notations --- p.15 / Chapter 2.2 --- User Behavior Model --- p.19 / Chapter 2.3 --- Movie Popularity --- p.22 / Chapter 2.4 --- Optimizing Server Load --- p.25 / Chapter 3 --- Analysis --- p.30 / Chapter 3.1 --- Request Scheduling Strategy --- p.31 / Chapter 3.2 --- Fixed Bandwidth Allocation --- p.33 / Chapter 3.2.1 --- FBA with Homogeneous Peers --- p.33 / Chapter 3.2.2 --- FBA with Heterogeneous Peers --- p.37 / Chapter 3.3 --- Perfect Fair Sharing --- p.37 / Chapter 3.3.1 --- PFS with Homogeneous Peers --- p.41 / Chapter 3.3.2 --- PFS with Heterogeneous Peers --- p.48 / Chapter 3.4 --- Fair Sharing with Fixed Degree --- p.50 / Chapter 3.5 --- FBA v.s. PFS v.s. FSFD --- p.53 / Chapter 3.6 --- Fair Sharing with Bounded Degree --- p.55 / Chapter 4 --- Adaptive Movie Replication Algorithms --- p.62 / Chapter 4.1 --- Adaptive RLB Algorithm --- p.63 / Chapter 4.2 --- Distributed Adaptive Replication Algorithm --- p.66 / Chapter 4.2.1 --- Other Algorithms --- p.70 / Chapter 5 --- Simulation --- p.73 / Chapter 5.1 --- Simulation Setting --- p.74 / Chapter 5.2 --- Simulation for PFS --- p.76 / Chapter 5.2.1 --- Stationary demand and static replication assignment --- p.77 / Chapter 5.2.2 --- Evaluate adaptive replication algorithms --- p.81 / Chapter 5.2.3 --- Performance analysis and discussion --- p.85 / Chapter 5.2.4 --- Copy Distribution of ARLB --- p.89 / Chapter 5.3 --- Simulation for FBA, FSFD and FSBD --- p.91 / Chapter 5.3.1 --- Model Validation --- p.91 / Chapter 5.3.2 --- Test of DAR Algorithm --- p.93 / Chapter 5.3.3 --- Robustness Validation --- p.96 / Chapter 6 --- Division of Labor --- p.102 / Chapter 6.1 --- Background: models and algorithms --- p.103 / Chapter 6.2 --- Availability versus Throughput --- p.106 / Chapter 6.2.1 --- ATD and its Drawbacks --- p.107 / Chapter 6.2.2 --- Coverage Assured Replication --- p.110 / Chapter 6.2.3 --- Automatic Division of Labor --- p.113 / Chapter 6.3 --- Optimal Coverage --- p.115 / Chapter 6.3.1 --- Save Most Popular Movies for P2P --- p.115 / Chapter 6.3.2 --- The Value of Optimal K --- p.118 / Chapter 6.3.3 --- Performance with or without CA --- p.121 / Chapter 6.4 --- Sensitivity --- p.122 / Chapter 6.4.1 --- θ versus K* --- p.122 / Chapter 6.4.2 --- The Effect of Popularity Skewness:θ --- p.123 / Chapter 6.4.3 --- System Parameters versus K* --- p.124 / Chapter 6.4.4 --- The Effect of System Parameters --- p.126 / Chapter 7 --- Related Work --- p.131 / Chapter 8 --- Conclusion --- p.141 / Chapter A --- Equation Derivation --- p.144 / Bibliography --- p.162