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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.
121

Tools assisted analog design, from reconfigurable design to analog design automation. / CUHK electronic theses & dissertations collection

January 2011 (has links)
To solve these issues, in this thesis the consistent effort in developing a quick tools assisted IC design platform is presented. First, a reconfigurable solution is proposed for some analog/mixed-signal (AMS) system which requires flexibility to a certain extent, such as a reconfigurable RFID solution for different communicating distances. Second, for further demand of increasing the flexibility, a novel approach for ADA is presented, which provides a highly automatic design flow for analog circuits to realize the "SPEC (Specification) in, GDS out" goal. Considering all kinds of higher order effects and uncertainties under deep submicron or even more advanced technologies, reliable design and fastness in processing are the two major concerns instead of the traditional pure optimization for best performance. To get a good balance among performance, reliability and turnaround time, an Application-Specific design flow with in-built knowledge-based algorithms is applied to deal with ADA issues under advanced technologies, which can quickly provide a reliable design with performance good enough to meet the SPECs for common use. / Unlike the highly automatic flow for digital circuits design, analog design automation (ADA) is still far from mature. For mixed-signal applications, analog circuit occupies only a small part on the layout, but the design requires a considerable amount of time and effort, making ADA extremely attractive. However, there are a lot more considerations to cover in analog design flow than its digital counterparts. In addition, the ever downscaling IC means analog circuits have to face more and more small-size effects, insufficient modelings, and the inaccuracy of classic formulas, which are quite difficult to handle. To solve the problem, various tools and methods have been proposed, but all in a digital-like flow, which are trying to develop general algorithms to realize circuit and layout synthesis. Up to now there is still a lot of problems. / Hong, Yang. / Adviser: C.S. Choy. / Source: Dissertation Abstracts International, Volume: 73-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 140-150). / 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.
122

Avaliação de projetos logísticos de RFID aplicados na indústria aeronáutica brasileira /

Castro, Jefferson Inácio de. January 2014 (has links)
Orientador: Jorge Muniz Junior / Coorientador: José Arnaldo Barra Montevechi / Banca: Valério Pamplona Salomon / Banca: Luis Alberto Ducan Rangel / Resumo: A tecnologia de Radio Frequency Identification (RFID) tornou-se um tema importante desde 2006, quando vários autores começaram a avaliá-la. A aplicação de RFID para processos industriais tem uma abordagem estratégica, objetivando a melhoria da satisfação dos clientes e criar novas oportunidades de negócios, bem como uma abordagem operacional com foco na eficiência operacional e na flexibilidade dos processos. A tecnologia é aplicada na logística e nos demais processos da cadeia de suprimentos com o objetivo do rastreamento dos materiais, aumento de visibilidade, aumento da eficiência operacional, redução dos desvios do processo e aumento da acessibilidade do inventário. Neste cenário, a presente dissertação tem como objetivo a avaliação de projetos logísticos aplicados à indústria aeronáutica brasileira com o uso do AHP - Analytic Hierarchy Process com ratings - passando pela identificação e avaliação das características que motivam e restringem a utilização da tecnologia através de uma revisão da literatura e pesquisa de campo / Abstract: Research on Radio Frequency Identification technology (RFID) has become an important issue since 2006 and several authors have begun to assess this technology. The application of RFID to industrial processes has a strategic approach, seeking to improve customer satisfaction and new business opportunities, and has an operational approach focusing on operational efficiency and flexibility of the processes. There is a great application of RFID in logistics, warehouse and supply chain processes seeking tracking materials, increase supply chain visibility, labor savings, shrinkage reduction and inventory visibility. In this scenario, this paper aims to evaluate logistics projects applied to the brazilian aircraft industry using the AHP - Analytic Hierarchy Process with ratings, in addition to the identification and evaluation of the characteristics that motivate and restrict the use of technology through a literature review and a survey / Mestre
123

Fast RFID counting under unreliable radio channels.

January 2009 (has links)
Sze, Wai Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 77-83). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.vi / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background and Related Work --- p.8 / Chapter 3 --- RFID Tag-set Cardinality estimation based on a Two-parameter implicit Channel Model --- p.13 / Chapter 3.1 --- System Model --- p.14 / Chapter 3.2 --- Number of Empty Slots Observed by the Reader --- p.16 / Chapter 3.3 --- Estimator Accuracy and Performance Analysis --- p.25 / Chapter 3.4 --- Results and Discussions --- p.32 / Chapter 3.5 --- Chapter Summary --- p.41 / Chapter 4 --- RFID Tag-set Cardinality estimation over Unknown Channel --- p.42 / Chapter 4.1 --- System Model --- p.43 / Chapter 4.2 --- Baseline: The Union-based approach --- p.45 / Chapter 4.2.1 --- Motivation --- p.46 / Chapter 4.2.2 --- Union Algorithm --- p.46 / Chapter 4.2.3 --- Analysis of the Union algorithm --- p.47 / Chapter 4.3 --- "Probabilistic Tag-counting over Lossy, Unknown channels via the Mh model" --- p.52 / Chapter 4.3.1 --- "Novel Interpretation of Mh for RFID Counting over Lossy, Unknown Channels" --- p.52 / Chapter 4.3.2 --- The Moment Estimator --- p.55 / Chapter 4.3.3 --- Sample Coverage Estimator --- p.57 / Chapter 4.3.4 --- Estimating the overall Tag population t --- p.59 / Chapter 4.4 --- Performance Validation and Comparison --- p.62 / Chapter 4.5 --- Chapter Summary --- p.65 / Chapter 5 --- Conclusions and Future Work --- p.73 / Chapter A --- Proof of Equation (3.6) in Chapter 3 --- p.75 / Bibliography --- p.77
124

Sensor systems for positioning and identification in ubiquitous computing

Jayabharath Kumar, Suri January 2006 (has links)
<p>Technologies for position sensing and identification are important to have in ubiquitous computing environments. These technologies can be used to track users, devices, and artefacts in the physical milieu, for example, locating the position of a cellular phone in av physical environment. The aim of this thesis was to survey and classify available technologies for location sensing and identification. </p><p>We have made a literature study on both commercial and research-oriented systems and technologies for use in indoor and outdoor environments. We compared the characteristics of the underlying sensing technologies with respect to physical size, sensing method, cost, and accuracy. We conclude the thesis with a set of recommendations to developers and discuss the requirements on future sensing technologies and their use in mobile devices and environments.</p>
125

Ubiquitous monitoring of distributed infrastructures /

Jiang, Bing, January 2006 (has links)
Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 134-141).
126

Crack detection using a passive wireless strain sensor

Lantz, Gabriel Antoine 29 August 2011 (has links)
Nearly one third of the 604,426 bridges in the United-States are either structurally deficient or functionally obsolete. Monitoring these bridges is essential to avoid catastrophic accidents. In steel bridges fatigue induced crack/rupture, which is one of the most common modes of failure, can be avoided if the crack is detected at the early stages of its formation. Cracks usually originate at stress concentration areas but their precise origin is random. Such strain concentration can be monitored with traditional strain gages, but their installation requires lengthy wires and equipment, which are expensive and labor intensive. Therefore wireless sensors are being developed to cope with these problems. In this work, a passive wireless strain sensor based on RFID technology is described. The sensor is a patch antenna that resonates at a certain frequency, which shifts in presence of strain. The relation between the resonance frequency and the strain is approximately linear. The slope of the relation is called sensitivity. The behavior of the sensor's sensitivity is studied using experimental work and simulations that couple electromagnetism and mechanics. The sensitivity measured in experiments and in simulations in presence of uniform strain is different. This difference is lower for the sensitivity in presence of a crack, probably due to a parameter variation that is currently not accurately modeled in the simulations.
127

Dynamic Categorization: What We Can Learn from the Emergent Arrangement of Physical Artifacts in Libraries

Krauss, Armin Martin 07 January 2011 (has links)
Radio frequency identification (RFID) is a technology used in many applications for the identification of objects. This thesis presents a concept of how libraries could use RFID technology to locate physical items within the library. The ability to locate items within the library changes the way users interact with physical material, creates new ways of user collaboration, and influences the ability to browse the shelves for physical items. Several implementation scenarios are presented in detail and implications on collaboration and browsing are analyzed.
128

Dynamic Categorization: What We Can Learn from the Emergent Arrangement of Physical Artifacts in Libraries

Krauss, Armin Martin 07 January 2011 (has links)
Radio frequency identification (RFID) is a technology used in many applications for the identification of objects. This thesis presents a concept of how libraries could use RFID technology to locate physical items within the library. The ability to locate items within the library changes the way users interact with physical material, creates new ways of user collaboration, and influences the ability to browse the shelves for physical items. Several implementation scenarios are presented in detail and implications on collaboration and browsing are analyzed.
129

Improved Performance of a Radio Frequency Identification Tag Antenna on a Metal Ground Plane

Prothro, Joel Thomas 18 May 2007 (has links)
Simulation and experiments quantify the effect of moving a horizontal dipole antenna close to a metal ground plane. Solutions to the radiation problems are offered.
130

Relationship between Frequency of RFID Tags and Its Ability to Penetrate Fresh Concrete

Sridharan, Rajasekaran 2010 May 1900 (has links)
The concrete maturity method can be utilized to determine in situ strength of concrete. It uses the temperature of concrete to determine a maturity index that can then be used to determine strength of concrete. However, monitoring the concrete temperature using thermocouples brings up a wiring issue, which is not advisable in an equipment and human intensive area like a construction site. One of the ways to get around this wiring issue is to use Radio Frequency Identification (RFID) technology, which is capable of transmitting information wirelessly. Previous research implemented using ultra high frequency RFID tags embedded in fresh concrete found that water could be the impediment for transmitting RFID signal from within concrete during early stages of curing. From literature it was found that lower the frequency, better the chances of the wave penetrating water. The objective of the research was to figure out whether the frequency of RFID tags has any relationship with the readability of RFID tags embedded in fresh concrete. For this investigation, low frequency, high frequency, and ultra high frequency RFID tags were tested within fresh concrete to see any difference between tags in terms of transmitting information. This experiment was carried out in a controlled space to reduce the number of variables affecting the experiment outcome. The low frequency, high frequency, and ultra high frequency RFID tags were placed within 2 in x 3 in x 2 in wooden formwork at a depth of 4 in, 8 in, and 12 in. Ready mix concrete was poured into the formwork and 3 concrete cubes were cast with the tags embedded within them. Readers that could be connected to a laptop were used to monitor and collect the time at which these RFID tags can be detected. The test showed that the RFID signals from the low frequency tags at all depths were detected as soon as concrete was poured. The Ultra High Frequency tags placed at the 4" level could be detected 15 minutes after concrete was poured. The UHF tags at the 8" level could be detected after 30 minutes. The UHF tags at the 12" level took on an average 2 hours to be detected from the vicinity of the formwork. The greater the depth at which the ultra high frequency tag was buried the longer it took for it to be detected. The high frequency tags could be detected only at the 4" level. The reason the performance of the HF card degraded in concrete could be because it uses an aluminum foil antenna which is more susceptible to the environment changing the relative permeability. A copper wire antenna could have fared better in this condition, increasing the chances of detecting the tag. Moreover a passive tag was used. The read range and chances of detection could have been increased had an active tag been used. The power of the reader that was used was also very less which might have contributed to the tag not being detected. Among the tags that were used in the experiment it was found that low frequency tags was the tag that could be detected the earliest after concrete was poured into the forms. However, the maximum read range of the tag observed in the experiment was 20" which is too small a distance to be used on an actual construction site.

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