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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.
81

Alias-free signal processing of nonuniformly sampled signals

Bland, Denise January 1998 (has links)
No description available.
82

Radio Frequency IDentification: : Challenges and opportunities in a marketing context

Hansen, Kim, Penasa, Laura January 2014 (has links)
An extensive amount of research has been conducted on Radio Frequency IDentification (RFID) in the context of logistics, supply chain and manufacturing. Additionally, marketing opportunities related to RFID usage have been argued to exist. Despite this, limited research has focused on RFID in a marketing context which constitutes the research gap for this study.  A literature review on the subject area yielded an overview of the existing literature within the field. The literature review identified a research gap that constitutes the purpose of this study. The purpose is to investigate the factors influencing the adoption of Radio Frequency IDentification technology and whether it enhances retailers’ marketing opportunities. The study was of a qualitative nature and was conducted through a multiple case study. Data was gathered through semi-structured interviews with four companies. An archival analysis was performed in addition to the interviews. The interview data reveals that RFID technology adoption still has barriers to overcome, especially in regards to the identified marketing opportunities. Based on the conclusions of this study recommendations for managerial implications were formed. The findings of the study were able to support previous research stating that the main challenge for RFID adoption is the cost of the equipment. However, the previously identified marketing opportunities were not fully supported by the interviewed companies, thus, this area of research needs to be developed further.
83

A follow-up study on wireless power transmission for unmanned air vechicles [sic vehicles] / follow-up study on wireless power transmission for unmanned air vehicles

Toh, Leng Huei 12 1900 (has links)
This thesis was a continuation in part of a NPS project relating to microwave wireless power transmission for micro air vehicles (MAVs). The concept of using microwaves for transferring power in free space has existed since the beginning of the 20th century. The emphasis of this thesis is the experimental study of powering micro air vehicles via the use of using a microstrip rectenna (rectifying antenna) at 10 GHz. A microstrip rectenna was built and experiments were conducted to measure the efficiency of the rectenna elements. The conversion of radio frequency (RF) power into usable DC power was performed by a rectenna. Its function could be broken down into the following four stages: reception of radio frequency (RF) power, prerectification filtering, rectification, and post-rectification filtering. A rectenna model based on past research by NPS students was simulated, built, and tested. The analysis and findings of the rectenna model were presented, with suggested improvements highlighted. / Technology Agency author (civilian).
84

An Analysis of the Radio Frequency Identification (RFID) Technology Implementation within an Independent Public Library System: A Case Study of the North Canton, Ohio Public Library

Lyons, Keith P. 01 January 2010 (has links)
An Analysis of the Radio Frequency Identification (RFID) Technology Implementation within an Independent Public Library System: A Case Study of the North Canton, Ohio Public Library by Keith P. Lyons June 2010 Public libraries require efficient control systems to maintain accurate inventories, statistics, and records of patron borrowing. Generally, public libraries use barcode technology to accomplish these tasks. Radio frequency identification (RFID) has gained the attention of public library personnel in recent years as a replacement for barcodes. RFID implementation contributes to improved staff productivity, increased operational efficiency, and improved item security as well. While potential benefits are significant, issues to consider prior to adoption include system costs, as well as privacy and security concerns. As a consequence of increased patron use and limited budgets, the role of RFID in the public library is promoted as a solution to many of today's challenges. RFID in the public library can assist by improving inventory tracking, improving customer service, and decreasing theft. Using the case study methodology in conjunction with the System Development Life Cycle (SDLC), the author examined RFID use at the North Canton Public Library and its capabilities in improving inventory tracking, providing item security, and supporting customer service. Qualitative data were collected using focused interviews, documentation, direct observation, and participant observation. Findings from this investigation revealed a significant decrease in time required to perform inventory tasks and an increase in time available for library staff to assist patrons. Additionally, evidence demonstrated an increase in the efficiency of patron records due to the automation of the checkout process. Patron privacy and data security were maintained by adherence to RFID implementation guidelines established by the American Library Association (ALA). The findings from this investigation provide public library administrators considering adoption of RFID with a thorough understanding of pre-implementation considerations and the benefits, drawbacks, logistical concerns, and privacy issues that must be addressed for successful results.
85

Implementation of a VANET Geo-Fence Based Adaptive Traffic Light Control Scheme

Unknown Date (has links)
In this thesis we extend the VANET-based approach to counting vehicles at a traffic light by implementing a Geo-fence Based Vehicle Counting Algorithm which supports the use of RFID technology. This implementation utilizes the concept of geo-fencing to create a Zone of Interest (ZOI) that sections off a roadway that is relevant to a traffic intersection. All vehicles in this ZOI are used to determine the required length of the green-cycle time. By utilizing vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) technologies, we broadcast beacons that are propagated to all vehicles in the ZOI from the infrastructure which in this case is the traffic light controller. These beacons are used to determine the last vehicle location in the ZOI. A timing algorithm ensures that the last vehicle broadcasts first. The beacons are sent using the IEEE 1609.4 Wireless Access in Vehicular Environments Standard Vendor Specific Action (VSA) frames on the Smart Drive Initiative Vehiclular Ad Hoc Networks testbed. This work is implemented in conjunction with the Vehicular Multi-technology Communication Device (VMCD) supported by the National Science Foundation. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
86

Spectrum sharing in large-scale and random geometric wireless networks / CUHK electronic theses & dissertations collection

January 2014 (has links)
The demand for larger user traffic capacity and better service quality for wireless communications has been increasing drastically in the past decade due to the widespread use of internet and smart phones. However, such demand is severely limited by the shortage of radio spectrum. One of the key enabling techniques to enhance spectrum utilization efficiency is spectrum sharing, which allows unlicensed secondary users to access the spectrum of a licensed primary network under interference constraints. Traditional spectrum sharing strategies developed for finite and deterministic networks require accurate information on user locations or channel gains. It is trivial that acquiring such information consumes substantial resources in large-scale and randomly deployed wireless networks. In this thesis, innovative spectrum sharing techniques for large-scale and random geometric wireless networks are explored by utilizing stochastic geometry models. Our study covers situations where each node of both primary and secondary networks is equipped with one or more than one antenna. We also consider the scenario when multiple secondary networks are present in the communication system. / We first review the various important aspects of spectrum sharing between one primary network and one secondary network where each node is equipped with only one single antenna. We analyze the successful transmission probability of each network in this case, and derive the corresponding optimal transmit power for the secondary network. The main technical challenge is to manage intra-network and inter-network interference caused by the stochastic nature of channel propagation and node distribution. Given a decrement limit for the successful transmission probability of each network, the optimal transmit power of the secondary network is determined to boost the spectrum sharing throughput while preventing individual networks from experiencing severe performance degradation. / Secondly, two multiple-input single-output networks are investigated to further improve the performance of spectrum sharing. Multiple transmit antennas manage aggregate interference by strengthening the desired signal and nulling undesired interferers, as far as possible. Partial zero-forcing beamforming is applied to spectrum sharing networks to quantify the possible density increase in the secondary users while meeting the outage requirements of other spectrum sharing users. Furthermore, we analyze the effects of the nulled interferers, and show how spectrum sharing opportunities can be enhanced in large-scale and random geometric wireless networks by wisely allocating the degrees of freedom for interference nulling. / Lastly, motivated by the evolution of wireless networks toward heterogeneity, we study spectrum sharing between one primary network and multiple secondary networks that are distinguished by system parameters, such as network densities and target data rates. A power allocation strategy is developed for the secondary networks to improve the overall spectrum sharing throughput while guaranteeing the quality-of-service of each network. The joint power allocation problem is transformed into a power ratio allocation strategy, and a quasi-closed form solution that allows for water-filling interpretation is obtained. / 由於互网和智能手機的廣泛應用,對於無線通信中更大的用戶傳輸容量以及更好的服務質量的需求在過去十年得到了長足的增長。但是,這些需求嚴重受限于無線頻譜的不足。作為提升頻譜利用率的主要技術之一,頻譜共享允許無執照的次級用戶在干擾受限的條件下使用屬於有執照的主用戶的頻譜。傳統的頻譜共享策略針對于有限的、確定性的網絡,需要準確的用戶位置信息或信道增益信息。在大規模隨機分佈的無線網絡中,獲取這些信息會消耗大量的資源。本論文利用隨機幾何模型對於大規模隨機幾何無線網絡中的頻譜共享新技術進行了探索。我們的研究涵蓋主用戶和次用戶網絡的每個節點配置單天線和多天線的多種情況。我們還考慮了系統中有多個次用戶的情況。 / 我們首先考慮的是一個主要網絡和一個次級網絡之間的頻譜共享問題,其中每個節點配置單天線。我們分析了這個場景中每個網絡的成功傳輸概率,並提出了最優化的次級用戶傳輸功率。主要的技術挑戰是管理由於信道傳播和節點分佈的隨機性而造成的網絡內部和網絡之間的干擾。為了提升頻普共享的吞吐量並且同時防止個體網絡的性能嚴重下降,次級用戶傳輸功率在給定每個網絡的成功傳輸概率的下降限制的情況下進行優化。 / 為了進一步提高頻譜共享的性能,我們進而研究了多輸入單輸出傳輸的雙網絡頻譜共享問題。發送端利用多個天線可以盡量增加倍號強度和削減干擾,從而管理整體的干擾。在符合用戶中斷概率的要求下,利用頻譜共享網絡中的部份迫零波束成形,我們量化了次級用戶的分佈密度增長。我們進一步分析了干擾源消去的影響,其結果顯示合理分配用於干擾消去的自由度可以增加大規模隨機幾何無線網絡中的頻譜共享機會。 / 最後,基於異構無線網絡的發展趨勢,我們考慮了一個主要網絡和多個次要網絡之間的頻譜共享問題。這些網絡的系統參數,如網絡密度和目標數據速率等,不盡相同。在保證個體網絡服務質量的前提下,為了加強頻譜共享的整體吞吐量,我們提出了多個次級網絡間的功率分配策略。我們把功率分配問題轉化為功率比例分配問題,從而得到了基於注水算法的近似解析解。 / Cai, Ran. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 143-155). / Abstracts also in Chinese. / Title from PDF title page (viewed on 09, December, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.
87

Anti-collision techniques for RFID systems.

January 2006 (has links)
Chiang Kong Wa. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 74-79). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Technology Overview --- p.4 / Chapter 2.1 --- Components of RFID Systems --- p.5 / Chapter 2.1.1 --- Tag --- p.6 / Chapter 2.1.2 --- Reader --- p.9 / Chapter 2.1.3 --- Software systems --- p.10 / Chapter 2.1.4 --- Communication infrastructure --- p.11 / Chapter 2.2 --- Frequency Regulations and Standards --- p.11 / Chapter 2.2.1 --- RFID frequency bands --- p.11 / Chapter 2.2.2 --- Standards --- p.12 / Chapter 2.3 --- Advantages and Limitations of RFID Technology --- p.14 / Chapter 2.4 --- Applications --- p.17 / Chapter 3 --- Background of Research --- p.20 / Chapter 3.1 --- Anti-collision methods for RFID systems --- p.22 / Chapter 3.1.1 --- Stochastic Anti-collision Protocols --- p.25 / Chapter 3.1.2 --- Deterministic Anti-collision Protocols --- p.27 / Chapter 4 --- Even-Odd Binary Tree Protocol --- p.30 / Chapter 4.1 --- Protocol Description --- p.31 / Chapter 4.2 --- Time Complexity Analysis --- p.34 / Chapter 4.3 --- Performance Evaluation --- p.37 / Chapter 4.4 --- Summary --- p.41 / Chapter 5 --- Prefix-Randomized Query-Tree Protocol --- p.44 / Chapter 5.1 --- Tag Identification - Known Tag Set Size --- p.45 / Chapter 5.1.1 --- Protocol Description --- p.45 / Chapter 5.1.2 --- Time Complexity Analysis --- p.47 / Chapter 5.1.3 --- Optimal Initial Prefix Length --- p.50 / Chapter 5.1.4 --- Optimal Number of Level-1 Nodes --- p.52 / Chapter 5.2 --- Tag Identification - Unknown Tag Set Size --- p.53 / Chapter 5.2.1 --- Initial Prefix Length Adaptation Algorithm --- p.54 / Chapter 5.2.2 --- Computing r*Δ(l) --- p.55 / Chapter 5.2.3 --- Optimal Choice of Step Size Δ --- p.56 / Chapter 5.3 --- Performance Evaluation --- p.59 / Chapter 5.4 --- Summary --- p.64 / Chapter 6 --- Conclusion and Future Work --- p.68 / Chapter 6.1 --- Conclusion --- p.68 / Chapter 6.2 --- Future Work --- p.70 / Bibliography --- p.74
88

Model order reduction techniques for PEEC modeling of RF & high-speed multi-layer circuits.

January 2006 (has links)
by Hu Hai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references. / Abstracts in English and Chinese. / Author's Declaration --- p.ii / Abstract --- p.iii / Acknowledgements --- p.vi / Table of Contents --- p.viii / List of Figures --- p.xi / List of Tables --- p.xiv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Overview of This Work --- p.2 / Chapter 1.3 --- Original Contributions in the Thesis --- p.3 / Chapter 1.4 --- Thesis Organization --- p.4 / Chapter Chapter 2 --- PEEC Modeling Background --- p.5 / Chapter 2.1 --- Introduction --- p.5 / Chapter 2.2 --- PEEC Principles --- p.6 / Chapter 2.3 --- Meshing Scheme --- p.10 / Chapter 2.4 --- Formulae for Calculating the Partial Elements --- p.12 / Chapter 2.4.1 --- Partial Inductance --- p.12 / Chapter 2.4.2 --- Partial Capacitance --- p.14 / Chapter 2.5 --- PEEC Application Example --- p.15 / Chapter 2.6 --- Summary --- p.17 / References --- p.18 / Chapter Chapter 3 --- Mathematical Model Order Reduction --- p.20 / Chapter 3.1 --- Introduction --- p.20 / Chapter 3.2 --- Modified Nodal Analysis --- p.21 / Chapter 3.2.1 --- Standard Nodal Analysis Method Review --- p.22 / Chapter 3.2.2 --- General Theory of Modified Nodal Analysis --- p.23 / Chapter 3.2.3 --- Calculate the System Poles Using MNA --- p.27 / Chapter 3.2.4 --- Examples and Comparisons --- p.28 / Chapter 3.3 --- Krylov Subspace MOR Method --- p.30 / Chapter 3.4 --- Examples of Krylov Subspace MOR --- p.32 / Chapter 3.5 --- Summary --- p.34 / References --- p.35 / Chapter Chapter 4 --- Physical Model Order Reduction --- p.38 / Chapter 4.1 --- Introduction --- p.38 / Chapter 4.2 --- Gaussian Elimination Method --- p.39 / Chapter 4.3 --- A Lossy PEEC Circuit Model --- p.44 / Chapter 4.3.1 --- Loss with Capacitance --- p.44 / Chapter 4.3.2 --- Loss with Inductance --- p.46 / Chapter 4.4 --- Conversion of Mutual Inductive Couplings --- p.47 / Chapter 4.5 --- Model Order Reduction Schemes --- p.50 / Chapter 4.5.1 --- Taylor Expansion Based MOR Scheme (Type I) --- p.51 / Chapter 4.5.2 --- Derived Complex-valued MOR Scheme (Type II) --- p.65 / Chapter 4.6 --- Summary --- p.88 / References --- p.88 / Chapter Chapter 5 --- Concluding Remarks --- p.92 / Chapter 5.1 --- Conclusion --- p.92 / Chapter 5.2 --- Future Improvement --- p.93 / Author's Publication --- p.95
89

Advanced power saving technologies for UHF band active RFID systems.

January 2006 (has links)
Wei Dacheng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references. / Abstracts in English and Chinese. / Table of Contents --- p.VIII / List of Tables --- p.XI / List of Figures --- p.XII / List of Abbreviations --- p.XV / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Introduction to RFID system --- p.1 / Chapter 1.2 --- Why we choose Active RFID system --- p.4 / Chapter 1.3 --- Objective of the research --- p.6 / Chapter 1.3.1 --- Requirement analysis --- p.7 / Chapter 1.3.2 --- Selection of RFID system and standard --- p.8 / Chapter 1.4 --- Original contribution of this dissertation --- p.9 / Chapter 1.5 --- Organization of the dissertation --- p.9 / Reference --- p.10 / Chapter Chapter 2 --- Implementation of An Active RFID System / Chapter 2.1 --- RFID System hardware design and related protocol --- p.1 / Chapter 2.2 --- Introduction to ISO 18000-7 --- p.7 / Chapter 2.3 --- Microcontroller specification --- p.12 / Chapter 2.4 --- RF model specifications --- p.14 / Chapter 2.5 --- Communication between a PC and a Reader --- p.15 / Chapter 2.6 --- Programming --- p.16 / Chapter 2.6.1 --- Procedure sequences of Reader and Tag --- p.17 / Chapter 2.6.2 --- Sequence of data transmission and reception --- p.24 / Chapter 2.6.3 --- CRC implementation --- p.28 / Chapter 2.7 --- Testing result --- p.31 / Reference --- p.35 / Chapter Chapter 3 --- Novel Power Saving Methods for an Active RFID System / Chapter 3.1 --- Some drawbacks of the existing Active RFID protocol --- p.1 / Chapter 3.1.1 --- Power consumption problem --- p.1 / Chapter 3.1.2 --- Multi-Reader problem --- p.9 / Chapter 3.2 --- Solutions of the Multi-Reader problem and power saving problem --- p.10 / Chapter 3.2.1 --- A solution to the power saving problem --- p.11 / Chapter 3.2.2 --- A solution to the Multi-Reader problem --- p.16 / Reference --- p.21 / Chapter Chapter 4 --- A Probe-fed Compact Half-wave Length Dipole Antenna for Active RFID System / Chapter 4.1 --- Requirement of an antenna for Active RFID system --- p.1 / Chapter 4.2 --- A probe-fed half-wave length dipole EE shape antenna for metallic object application --- p.2 / Chapter 4.3 --- Electromagnetic simulation results --- p.5 / Chapter 4.4 --- Operating principle analysis --- p.9 / Chapter 4.5 --- Using V shape structure to increase the bandwidth --- p.19 / Chapter 4.6 --- Prototyping and measurement results --- p.22 / Chapter 4.7 --- Conclusion --- p.28 / Reference --- p.29 / Chapter Chapter 5 --- Conclusion
90

A theory of RFID anti-collision mechanisms. / CUHK electronic theses & dissertations collection

January 2010 (has links)
Due to the recent advances in semiconductor technology, the Radio Frequency Identification (RFID) technology is approaching the critical point for inventory application in global supply chain logistics. Its unique advantage to identify multiple tags simultaneously can remove large amount of labor-intensive scanning for inventory control and checkout process. To realize multiple-tag-identification, the tag collision problem, which is due to the signal collision of simultaneous transmission by multiple tags, needs to be solved. / Over the years, many different RFID systems and anti-collision algorithms were proposed, but a uniform theory which fully analyzes the anti-collision system is still lacking. Most of the previous work treated the RFID system as a special kind of Random Access (RA) system and designed anti-collision algorithms to maximize the temporary throughput. In this thesis, we provide a theoretical framework for the RFID anti-collision system. We differentiate the RFID system with the RA system and propose a general model for all types of the RFID systems. We also provide a general method for algorithm optimization in different RFID systems. As special examples, we analyze some popular RFID systems and derive the optimal algorithms under the system constraints. These optimal results are verified by computer simulation. / Zhu, lei. / Adviser: Tak-shing Peter Yum. / Source: Dissertation Abstracts International, Volume: 73-03, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 152-156). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

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