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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

臺北水源特定區協建經費政策績效評估研究

藍瑞珉 Unknown Date (has links)
水資源保護區與國土開發利用,都是國家重要政策,但兩者在本質上會有衝突,限制水資源保護區的土地開發利用,對受限制區的經濟、產業發展有一定程度的負面影響,為了讓全國的水源區及保護區,都有公平的回饋,並且落實「使用者付費、限制者受益」的社會公平正義暨有效的水資源管理及違法取締,於民國九十三年六月十一日,立法院三讀通過「自來水法」第十二條之一修正。臺北水源特定區居民希望將現行由台北市自來水水費每度徵收兩毛錢做為協助地方建設經費之「協建經費」名稱改為「回饋金」,因為水源特定區內的地方建設項目,本來就是政府應該做的工作,目前的「協建經費」是把應拿來補償水源區居民受到權益限制及損失的回饋金,用來做政府本來應該做的地方建設,等於變相剝削了水源特定區居民的權益。而依照水利署對目前自來水法修正的解釋中說明,自來水法於九十三年六月修正通過後屆時將訂定施行細則,並在各地成立運用小組,可依各地方需求在保育費使用上,於社福、文化、教育、產業推廣、土地徵收補償等相關項目上各自訂立適當使用比例,而未來保育費的徵收,在施行細則中回饋金的徵收費率將是隨水費附徵百分之五到百分之十五,若以百分之五徵收比例計算,目前每年協建經費的金額約一億多元,而未來開徵的「水源保育與回饋費」預期可達目前金額一倍以上。而一旦「水源保育與回饋收費辦法」暨相關施行細則通過後,開徵後經費的使用,更需有效率的執行與管理與監督功能,才能落實水資源回饋金的功用,達到政府照顧臺北水源特定區內居民的美意。 臺北水源特定區協建經費政策於臺北水源特定區內實施,從民國八十七年第一期經費撥入至今的這段期間,協建經費使用的績效是否能達到當初政策目的,符合多元利益相關人的期待,值得做相關的研究與探討,期能透過此研究讓國人更瞭解協建經費之意涵及效益。
22

Laboratory and field trials evaluation of transmit delay diversity applied to DVB-T/H networks

Di Bari, Raffaele January 2010 (has links)
The requirements for future DVB-T/H networks demand that broadcasters design and deploy networks that provide ubiquitous reception in challenging indoors and other obstructed situations. It is essential that such networks are designed cost-effectively and with minimized environmental impact. The use of transmit diversity techniques with multiple antennas have long been proposed to improve the performance and capacity of wireless systems. Transmit diversity exploits the scattering effect inherent in the channel by means of transmitting multiple signals in a controlled manner from spatially separated antennas, allowing independently faded signals to arrive at the receiver and improves the chances of decoding a signal of acceptable quality. Transmit diversity can complement receive diversity by adding an additional diversity gain and in situations where receiver diversity is not practical, transmit diversity alone delivers a comparable amount of diversity gain. Transmit Delay Diversity (DD) can be applied to systems employing the DVB standard without receiver equipment modifications. Although transmit DD can provide a gain in NLOS situations, it can introduce degradation in LOS situation. The aim of this thesis is to investigate the effectiveness in real-word applications of novel diversity techniques for broadcast transmitter networks. Tests involved laboratory experiments using a wireless MIMO channel emulator and the deployment of a field measurement campaign dedicated to driving, indoor and rooftop reception. The relationship between the diversity gain, the propagation environment and several parameters such as the transmit antenna separation, the receiver speed and the Forward Error Correction Codes (FEC) configuration are investigated. Results includes the effect of real-word parameter usually not modeled in the software simulation analysis, such as antenna radiation patterns and mutual coupling, scattering vegetation impact, non-Gaussian noise sources and receiver implementation. Moreover, a practical analysis of the effectiveness of experimental techniques to mitigate the loss due to transmit DD loss in rooftop reception is presented. The results of this thesis confirmed, completed and extended the existing predictions with real word measurement results.
23

Measuring Bond Mutual Fund Performance with Portfolio Characteristics

Moneta, Fabio January 2009 (has links)
Thesis advisor: Pierluigi Balduzzi / Employing a novel data set of portfolio weights from 1997 to 2006, the performance of taxable bond mutual funds is studied. The timing ability of fund managers is examined considering different asset allocation choices such as asset class, credit quality allocation, and portfolio maturity decisions. I show that active managers engage in strategies of rotating their portfolios across fixed-income sectors and bond characteristics. Some bond funds exhibit successful timing ability by adopting these strategies. Comparing fund returns plus expenses and transaction costs with the returns of a portfolio that is invested in the previously disclosed holdings, I document that active managers exhibit some ability to select securities that deliver better returns than the securities in the indices. In particular, on average, active managers generate gross returns of 1% per annum over the benchmark portfolio constructed using past holdings. / Thesis (PhD) — Boston College, 2009. / Submitted to: Boston College. Carroll School of Management. / Discipline: Finance.
24

Performance Evaluation of QUIC protocol under Network Congestion

Srivastava, Amit 18 April 2017 (has links)
TCP is a widely used protocol for web traffic. However, TCP€™s connection setup and congestion response can impact web page load times, leading to higher page load times for users. In order to address this issue, Google came out with QUIC (Quick UDP Internet Connections), a UDP-based protocol that runs in the application layer. While already deployed, QUIC is not well-studied, particularly QUIC€™s congestion response as compared to TCP€™s congestion response which is critical for stability of the Internet and flow fairness. To study QUIC€™s congestion response we conduct three sets of experiments on a wired testbed. One set of our experiments focused on QUIC and TCP throughput under added delay, another set compared QUIC and TCP throughput under added packet loss, and the third set had QUIC and TCP flows share a bottleneck link to study the fairness between TCP and QUIC flows. Our results show that with random packet loss QUIC delivers higher throughput compared to TCP. However, when sharing the same link, QUIC can be unfair to TCP. With an increase in the number of competing TCP flows, a QUIC flow takes a greater share of the available link capacity compared to TCP flows.
25

Application Performance Evaluation for IBeacon In-Room Localization Technology Using CRLB

Yang, Yang 04 May 2016 (has links)
This thesis is a part of a research project performed by two MS students, Zhouchi Li and the author. The overall objective of the project is the design, implementation and performance evaluation of algorithms for newborns localization and tracking in hospitals using Apple iBeacon technology. Although we were working on the project together, I lead performance evaluation of the in-room localization system using Cramer Rao Lower Bound (CRLB). My partner, Zhouchi Li, leads modeling the path-loss of iBeacons and presence detection algorithms. This thesis describes the project with a focus on my individual contributions in CRLB analysis under different iBeacon deployment patterns as well as performance evaluation using practical characteristics of shadow fading. Today, Wi-Fi localization is the most popular indoor localization technique, which provides an accuracy of a few meters to distinguish the presences in different rooms of a building. With the recent introduction of iBeacon by Apple, possibility of more accurate in-room localization has emerged for specific applications such as locating newborns inside a hospital. The iBeacon uses Bluetooth Low Energy (BLE) technology that broadcasts beacons with unique information to the nearby receivable devices such as iPhone and android smart phones. The RSS of these beacons can be used to estimate the location and to construct an in-room localization system. In this thesis, we investigate in-room localization system using iBeacon for the newborns in hospitals with an accuracy of about 1 meter. We firstly present an in-room localization system using RSS from iBeacon. Then, based on the traditional Cramer-Rao Lower Bound (CRLB) we analyze the optimal deployment strategy for different iBeacon deployment patterns in the nursery room. Finally, we introduce a novel approach for calculation of the CRLB which includes practical conditions to analyze the influence of variable variance of shadow fading and coverage probability.
26

Video Streaming and Multimedia Broadcasting Over Vehicular Ad Hoc Networks

Naeimipoor, Farahnaz 30 January 2013 (has links)
Video dissemination capabilities are crucial for the deployment of many services over VANETs. These services range from enhancing safety via the dissemination of video from the scene of an accident, to advertisement of local services or businesses. This work considers the infrastructure-less scenario of VANETs and dissemination of video content over this network environment, which is extremely challenging mainly due to its dynamic topology and stringent requirements for video streaming. This study discusses issues and challenges that need to be tackled for disseminating high-quality video over VANETs. Furthermore it surveys and analyzes the suitability of different existing solutions aimed towards effective and efficient techniques for video dissemination in vehicular networks. As a result, a set of the most promising techniques are selected, described in detail and evaluated based on standard terms in quality of service. This thesis also discusses efficiency and suitability of these techniques for video dissemination and compares their performance over the same network condition. In addition, a detailed study on the effect of network coding on video dissemination protocols has been conducted to guide how to employ this technique properly for video streaming over VANETs. From this study, a summary of the observations was obtained and used to design a new hybrid solution by deploying robust and efficient techniques in number of existing protocols in an optimal manner. The proposed hybrid video dissemination protocol outperforms other protocols in term of delivery ratio and complies with other quality-of-service requirements for video broadcasting over vehicular environments.
27

Performance of data aggregation for wireless sensor networks

Feng, Jie 02 July 2010
This thesis focuses on three fundamental issues that concern data aggregation protocols for periodic data collection in sensor networks: <i>which</i> sensor nodes should report their data, <i>when</i> should they report it, and should they use <i>unicast</i> or <i>broadcast</i> based protocols for this purpose. <p> The issue of when nodes should report their data is considered in the context of real-time monitoring applications. The first part of this thesis shows that asynchronous aggregation, in which the time of each nodes transmission is determined adaptively based on its local history of past packet receptions from its children, outperforms synchronous aggregation by providing lower delay for a given end-to-end loss rate. <p> Second, new broadcast-based aggregation protocols that minimize the number of packet transmissions, relying on multipath delivery rather than automatic repeat request for reliability, are designed and evaluated. The performance of broadcast-based aggregation is compared to that of unicast-based aggregation, in the context of both real-time and delay-tolerant data collection. <p> Finally, this thesis investigates the potential benefits of dynamically, rather than semi-statically, determining the set of nodes reporting their data, in the context of applications in which coverage of some monitored region is to be maintained. Unicast and broadcast-based coverage-preserving data aggregation protocols are designed and evaluated. The performance of the proposed protocols is compared to that of data collection protocols relying on node scheduling.
28

Structural Performance Evaluation of Interlocking Concrete Pavement Crosswalk Designs

Adhikari,Sudip 05 December 2008 (has links)
Interlocking Concrete Pavements (ICP) have been successfully used in many pavement applications all across the world. ICP design and analysis methods, construction practices and materials specifications have been developed. However, there is very limited field data to quantify structural performance with respect to traffic and environmental loadings. The interaction between traffic loadings and environmental factors needs to be explored in order to improve relationships between pavement performance and response. Pavement performance prediction in terms of fatigue cracking and surface rutting are essential for any mechanistically-based pavement design method. The estimation of the expected fatigue performance in the field is based on the quantification of the maximum tensile strain in bound base layers and the expected rutting performance is based on maximum vertical stress/strain in granular layers. This thesis presents an innovative research project involving the design, construction, instrumentation, performance modeling and distress evaluation of seven ICP crosswalks with four different design assemblies. The research projects were constructed at the Centre for Pavement and Transportation Technology (CPATT) test track and at the University of Waterloo ring road. Each of the test sections is instrumented with structural and environmental sensors of sensors to monitor the pavement performance under heavy truck traffic, typical municipal loadings and to quantify environmental effects. A database is generated and the measured stress, strain, temperature and moisture measurements are analysed to evaluate the expected long-term performance of the structural components of ICP crosswalk designs.
29

Structural Performance Evaluation of Interlocking Concrete Pavement Crosswalk Designs

Adhikari,Sudip 05 December 2008 (has links)
Interlocking Concrete Pavements (ICP) have been successfully used in many pavement applications all across the world. ICP design and analysis methods, construction practices and materials specifications have been developed. However, there is very limited field data to quantify structural performance with respect to traffic and environmental loadings. The interaction between traffic loadings and environmental factors needs to be explored in order to improve relationships between pavement performance and response. Pavement performance prediction in terms of fatigue cracking and surface rutting are essential for any mechanistically-based pavement design method. The estimation of the expected fatigue performance in the field is based on the quantification of the maximum tensile strain in bound base layers and the expected rutting performance is based on maximum vertical stress/strain in granular layers. This thesis presents an innovative research project involving the design, construction, instrumentation, performance modeling and distress evaluation of seven ICP crosswalks with four different design assemblies. The research projects were constructed at the Centre for Pavement and Transportation Technology (CPATT) test track and at the University of Waterloo ring road. Each of the test sections is instrumented with structural and environmental sensors of sensors to monitor the pavement performance under heavy truck traffic, typical municipal loadings and to quantify environmental effects. A database is generated and the measured stress, strain, temperature and moisture measurements are analysed to evaluate the expected long-term performance of the structural components of ICP crosswalk designs.
30

Performance of data aggregation for wireless sensor networks

Feng, Jie 02 July 2010 (has links)
This thesis focuses on three fundamental issues that concern data aggregation protocols for periodic data collection in sensor networks: <i>which</i> sensor nodes should report their data, <i>when</i> should they report it, and should they use <i>unicast</i> or <i>broadcast</i> based protocols for this purpose. <p> The issue of when nodes should report their data is considered in the context of real-time monitoring applications. The first part of this thesis shows that asynchronous aggregation, in which the time of each nodes transmission is determined adaptively based on its local history of past packet receptions from its children, outperforms synchronous aggregation by providing lower delay for a given end-to-end loss rate. <p> Second, new broadcast-based aggregation protocols that minimize the number of packet transmissions, relying on multipath delivery rather than automatic repeat request for reliability, are designed and evaluated. The performance of broadcast-based aggregation is compared to that of unicast-based aggregation, in the context of both real-time and delay-tolerant data collection. <p> Finally, this thesis investigates the potential benefits of dynamically, rather than semi-statically, determining the set of nodes reporting their data, in the context of applications in which coverage of some monitored region is to be maintained. Unicast and broadcast-based coverage-preserving data aggregation protocols are designed and evaluated. The performance of the proposed protocols is compared to that of data collection protocols relying on node scheduling.

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