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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.
221

Heterogeneous RFID framework design, analysis and evaluation

Botero, Oscar 14 May 2012 (has links) (PDF)
The Internet of Things paradigm establishes interaction and communication with a huge amount of actors. The concept is not a new-from-scratch one; actually, it combines a vast number of technologies and protocols and surely adaptations of pre-existing elements to offer new services and applications. One of the key technologies of the Internet of Things is the Radio Frequency Identification just abbreviated RFID. This technology proposes a set of solutions that allow tracking and tracing persons, animals and practically any item wirelessly. Considering the Internet of Things concept, multiple technologies need to be linked in order to provide interactions that lead to the implementation of services and applications. The challenge is that these technologies are not necessarily compatible and designed to work with other technologies. Within this context, the main objective of this thesis is to design a heterogeneous framework that will permit the interaction of diverse devices such as RFID, sensors and actuators in order to provide new applications and services. For this purpose in this work, our first contribution is the design and analysis of an integration architecture for heterogeneous devices. In the second contribution, we propose an evaluation model for RFID topologies and an optimization tool that assists in the RFID network planning process. Finally, in our last contribution, we implemented a simplified version of the framework by using embedded hardware and performance metrics are provided as well as the detailed configuration of the test platform
222

無線射頻識別(RFID)應用於檔案典藏單位庫房管理可行性之研究 / A feasibility study of RFID application in archival repository management

王鈺蕙, Wang, Yu Hui Unknown Date (has links)
檔案是產生者因其業務活動而產生,視該文件所具有的重要價值、稽憑價值與特殊價值等而被留存於各機關庫房內,當保存期限屆滿時,再將其移轉至適當的檔案典藏單位中典藏,並賦予法律、文化和研究等功用,讓社會大眾加以應用。因此檔案典藏單位是蒐集、整理、儲存與提供檔案資訊之處所,以妥善典藏檔案,並維護檔案安全為主要目的。其中庫房則是檔案典藏單位的中樞命脈。為能達到有效運用人力資源、減少找尋檔案所耗費的時間、即時掌握檔案動態、加速庫房清查等效能,檔案典藏單位可採取無線射頻識別(Radio Frequency Identification, RFID)協助管理工作。 本研究之目的主要分析檔案典藏單位與圖書館兩者於應用RFID之異同及探究國內檔案典藏單位運用RFID之可行性,以提出RFID應用於檔案典藏單位庫房管理之建議。本研究採用「深度訪談法」,主要訪談六所建置單位,以瞭解建置動機、使用成效及建置單位對RFID的看法等。並訪談五間檔案典藏單位對RFID應用之看法。 根據訪談結果,提出結論如下:一、圖書館運用RFID情形:RFID建置之初多以資訊背景人員為負責人,以提供多元服務予讀者為主要目的,且承辦RFID單位名稱多元化,使用時認為RFID於流通成效最佳,手持式讀寫器之成效則有待改善;二、檔案典藏單位庫房管理現況及RFID導入之可行性:研究結果發現金屬檔案架對RFID會產生干擾,且檔案典藏單位經費緊縮、需求性不如圖書館、政府推動電子化公文,無紙化世界即將來臨,將導致載體改變,會影響RFID應用。 由研究結果針對RFID應用於檔案典藏單位庫房管理可行性之研究歸納檔案使用率(utility rate)、館藏數量、庫房管理及撥用經費等四部分建議:一、建議優先使用RFID於檔案使用頻率較高的單位;二、建議優先使用RFID於館藏量較大的典藏單位;三、將RFID控管溫濕度功能應用至庫房管理;四、撥用經費建置RFID於部分檔案。 / Records are created in the process of executing various tasks and activities, whose intrinsic, evidential and special value is used to determine if such items require archiving. Upon expiration of records from these archives, subsequent appraisal and transfer to more suitable public archives allows society to use these records in legal, cultural, or research studies and fields, and also for other future uses. Thus, an archival repository is the ideal entity for the acquisition, organization, storage, and public access supplier for records, as well as serving a primary purpose of maintaining both a proper storage location and the security and preservation of records. Among the various responsibilities in an archival institute, storage is the most important aspect. In order to most efficiently utilize human resources and costs associated with searching and moving records, as well as to reduce collection inventory times, archival repositories can utilize RFID technology to aid in their administration responsibilities. This study analyzes and compares similarities and differences between RFID in archives and libraries, and also investigates RFID feasibility, and makes appropriate recommendations for RFID usage, applications, administration and usage models in archival repository management. This study used in-depth interviews, six from libraries, compiling their factors for RFID usage, results with the technology, and opinions regarding this new technology. In addition, five archives were interviewed regarding RFID applications and opinions. Based on these interviews, it can be concluded: First, in libraries, initial deployment of this technology used employees well-versed in information technology fields, RFID enables provision of multiple new user services, implementing department titles varied from place to place, circulation departments benefitted the most from RFID usage, and RFID handheld reader usage needs improved methods and results. Second, regarding current RFID usage in an archives institution, RFID usage in metal storage shelves has shown signal interference, RFID faces significantly higher cost barriers, funding issues show RFID is better suited for library usage models, government is shifting towards e-documents, and a global information paradigm shift from a physical paper medium to a paperless medium, will effect RFID applications. From these conclusions, four recommendations arise regarding the utilization rate of RFID, quantity of departments, storage administration, and sufficient funding: 1. RFID is more suitable in higher usage archival institutions. 2. RFID is more suitable in repositories with larger quantities of records. 3. RFID temperature and humidity features can be enabled for greater control and management in storage administration. 4. Sufficient funds must be allocated to implement RFID for important records.
223

The dynamic impact of monetary policy on regional housing prices in the United States

Fischer, Manfred M., Huber, Florian, Pfarrhofer, Michael, Staufer-Steinnocher, Petra 16 November 2018 (has links) (PDF)
This paper uses a factor-augmented vector autoregressive model to examine the impact of monetary policy shocks on housing prices across metropolitan and micropolitan regions. To simultaneously estimate the model parameters and unobserved factors we rely on Bayesian estimation and inference. Policy shocks are identified using high-frequency suprises around policy announcements as an external instrument. Impulse reponse functions reveal differences in regional housing price responses, which in some cases are substantial. The heterogeneity in policy responses is found to be significantly related to local regulatory environments and housing supply elasticities. Moreover, housing prices responses tend to be similar within states and adjacent regions in neighboring states. / Series: Working Papers in Regional Science
224

Design and modelling of passive UHF RFID tags for energy efficient liquid level detection applications : a study of various techniques in the design, modelling, optimisation and deployment of RFID reader and passive UHF RFID tags to achieve effective performance for liquid sensing applications

Atojoko, Achimugu A. January 2016 (has links)
Sewer and oil pipeline spillage issues have become major causes of pollution in urban and rural areas usually caused by blockages in the water storage and drainage system, and oil spillage of underground oil pipelines. An effective way of avoiding this problem will be by deploying some mechanism to monitor these installations at each point in time and reporting unusual liquid activity to the relevant authorities for prompt action to avoid a flooding or spillage occurrence. This research work presents a low cost energy efficient liquid level monitoring technique using Radio Frequency Identification Technology. Passive UHF RFID tags have been designed, modelled and optimized. A simple rectangular tag, the P-shaped tag and S-shaped tag with UHF band frequency of operation (850-950 MHz) has been designed and modelled. Detailed parametric analysis of the rectangular tag is made and the optimised design results analysed and presented in HFSS and Matlab. The optimised rectangular tag designs are then deployed as level sensors in a gully pot. Identical tags were deployed to detect 4 distinct levels in alternate positions and a few inches in seperation distance within the gully pot height (Low, Mid, High and Ultra high). The radiation characteristic of tag sensors in deployment as modelled on HFSS is observed to show consistent performance with application requirements. An in-manhole chamber antenna for an underground communication system is analysed, designed, deployed and measured. The antenna covers dual-band impedance bandwidths (i.e. 824 to 960 MHz, and 1710 to 2170 MHz). The results show that the antenna prototype exhibits sufficient impedance bandwidth, suitable radiation characteristics, and adequate gains for the required underground wireless sensor applications. Finally, a Linearly Shifted Quadrifilar Helical Antenna (LSQHA) designed using Genetic Algorithm optimisation technique for adoption as an RFID reader antenna is proposed and investigated. The new antenna confirms coverage of the RFID bandwidth 860-960 MHz with acceptable power gain of 13.1 dBi.
225

Etude de qualité et de stabilité des réseaux aéronautiques embarqués HVDC / Quality and stability studies of aircraft embedded networks HVDC

Charrada, Madiha 21 February 2013 (has links)
Dans le contexte du concept de l’avion «plus électrique », l’électricité prend une part croissante dans les systèmes embarqués aéronautiques. Ainsi, de nombreuses évolutions ont eu lieu, concernant les réseaux de bord, notamment l’architecture du réseau qui est devenue de plus en plus complexe, intégrant de nombreux équipements de différentes natures ; ceci entraîne de multiples questions relatives à la qualité et la stabilité du réseau. C’est dans ce contexte que s’inscrivent ces travaux de thèse, qui aboutissent d’une part à la mise en œuvre de méthodes d’analyse de la stabilité et de la qualité du réseau aéronautique embarqué et d’autre part à l’analyse de couplage entre plusieurs équipements connectés sur un seul réseau. Les études menées au cours de ces travaux reposent sur l’utilisation des expressions analytiques représentant le comportement fréquentiel de réseaux continus. Une méthode de calcul basée sur les lois de la physique a été développée et validée par des approches de simulation et d’expérimentation. Par ailleurs, en absence d’un modèle analytique, nous choisissons de déterminer l'expression littérale du modèle équivalent du réseau à partir de l'identification des données issues de l’approche expérimentale en se basant sur des algorithmes d'optimisation. Ces modèles analytiques sont associés aux critères mathématiques de stabilité (Routh-Hurwitz, MiddleBrook), et aux contraintes de qualité imposées par les standards aéronautiques, dans le but de dimensionner les éléments de filtrage à placer entre le réseau et l’équipement. Le calcul des composants assurant le filtrage repose sur la recherche d’une solution optimale : nous introduisons les algorithmes d’optimisation utilisés en première étape, et nous proposons par la suite une formulation de la procédure de calcul des paramètres du filtre pour une meilleure illustration des résultats intéressants pour un concepteur de réseau. Enfin, nous clôturons ce travail par une analyse des couplages entre plusieurs équipements connectés sur un réseau continu et nous concluons par une approche expérimentale afin d’appuyer les résultats théoriques. / In the concept of the "more electric" aircraft, power takes an increasing proportion in aeronautic embedded systems. So many changes have occurred on board networks, including the network architecture that has become more and more complex, integrating many different types of equipment that causes quality and stability issues on the network. In this context that this thesis is inscribed, firstly it leads to the implementation of methods for stability and quality analyzing of the embedded network and secondly to coupling analysis of several devices connected to a single network. Studies conducted in this work are based on analytical expressions representing the frequency behavior of networks. A compute based on fundamental physical laws has been developed and validated by simulation and experimental approaches. Moreover, in the absence of an analytical model, we choose to determine the literal expression of the equivalent model of the network by identifying data, come from the experimental approach, using optimization algorithms. These analytical models are associated with mathematical criteria: Routh-Hurwitz, Middlebrook, and quality constraints imposed by aeronautic standards, in order to size the elements of the filter cell placed between the voltage source and the equipment to ensure the stability and quality of the entire system. The sizing of cell parameters based on optimal search by means of optimization algorithms in the first step, and then we propose a formulation of the calculation procedure of the filter parameters to illustrate some interesting results for designer’s network. Finally, we close this work with a coupling analysis of several devices connected to a single DC bus and we conclude by an experimental approach to support the theoretical results.
226

Extensões ao protocolo de comunicações EPCGloboal para tags Classe 1 utilizando autenticação com criptografia de baixo custo para segurança em identificação por radiofrequencia.

Mota, Rafael Perazzo Barbosa 31 May 2006 (has links)
Made available in DSpace on 2016-06-02T19:05:17Z (GMT). No. of bitstreams: 1 DissRPBM.pdf: 1011856 bytes, checksum: 715ebb8b484f0962fc766a3efbebb601 (MD5) Previous issue date: 2006-05-31 / Financiadora de Estudos e Projetos / EPCGlobal communication protocol for RFID (Radio Frequency Identification) does not ensure security and privacy for its system users. This fact makes possible several kinds of security problems on RFID technology usage justifying that security mechanisms should be added to communication protocol preserving the existing standards. This work proposal is based on communication authentication usage making use of low-cost cryptography with the TEA algorithm. The proposed mutual authentication mechanism was specified and proved using BAN logic. All protocol specification has considered the EPCGlobal standard for Class 1 tags as base adding security and privacy extensions to data communication to get protection against several attacks. The results from this work include an authentication protocol formal specification with cryptography allowing this way the protocol standardization using as base the current Class 1 protocol. / O protocolo de comunicação para a Identificação por Radiofreqüência (RFID- Radio Frequency Identification), definido como padrão pela EPCGlobal, não oferece mecanismos para a garantia de segurança e privacidade aos usuários do sistema. Esta característica possibilita a presença de diversos tipos de problemas no emprego da tecnologia justificando que novos mecanismos de segurança sejam incorporados diretamente ao protocolo de comunicação, preservando os padrões existentes. A proposta deste trabalho baseia-se na utilização de autenticação da comunicação com emprego de criptografia de baixo custo utilizando o algoritmo TEA. O mecanismo de autenticação mútua proposto foi especificado e validado com lógica BAN. Toda a especificação do protocolo considerou o padrão EPCGlobal para tags Classe 1 como base, adicionando extensões visando combater as possibilidades de ataques relacionados à segurança e privacidade na comunicação dos dados. Os resultados obtidos com este trabalho incluem a especificação formal de um protocolo de autenticação com criptografia, permitindo a padronização deste protocolo baseado no padrão para tags Classe 1 e preservando a especificação padrão base.
227

Modelagem e simulação do deslocamento de pessoas para estimativa de formação de grupos

Véras, Frank César Lopes 25 February 2013 (has links)
Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2016-02-05T15:54:58Z No. of bitstreams: 1 arquivototal.pdf: 4833402 bytes, checksum: 88ffcf3db8082fc50d986d744b72fd34 (MD5) / Made available in DSpace on 2016-02-05T15:54:58Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4833402 bytes, checksum: 88ffcf3db8082fc50d986d744b72fd34 (MD5) Previous issue date: 2013-02-25 / The use of Wireless Sensor Networks (WSN) has been widespread in many areas of research and application. The purpose of this work is a study on how to use sensors to monitor people on the move, having a WSN as a way in which the search will occur, but in order to predict the formation of groups in certain regions. For this work the network was designed and tested in the simulator Ptolemy II, using the ZigBee Communication protocol, where the sensors were positioned according to a Cartesian coordinate system. The WSN will detect people and identify common patterns of movement, such as speed, direction and type of movement, using parameters set in the simulator. People involved in the groups will be identified by RFID (Radio Frequency Identification) attached to his body. The movement of the crowd had its mathematical formalization based on parameters such as position of the group, number of people per group and duration of movement that define the characteristics necessary to simulate this scenario. From the formalization of the movement of the crowd, many data are collected at predetermined time intervals and interpreted by an algorithm, through the exchange of messages between sensors, estimates the crowd forming in the region defined as the target. In this work, were inserted charts and graphs that reflect the actual number of people moving towards the real target. These data are generated from the intense exchange of messages between sensors, obeying some parameters that favor established and the algorithm that estimates the crowd at the target formation at any given time. The accuracy of the prediction was measured by the amount of alarms issued that estimate and the formation of agglomerations of people in a given region. Thus, the identification of individuals by sensors is interpreted according to the possibility of formation of groups and their values disseminated by the network. The proposal is that this action will facilitate the process of decision making and thus help to characterize the formation of crowds. / O uso das Redes de Sensores sem Fio (RSSF) tem sido difundido em diversas áreas de pesquisa e aplicação. A proposta deste trabalho é um estudo sobre como utilizar sensores para monitorar pessoas em movimento, tendo uma RSSF como meio no qual a pesquisa deverá ocorrer, porém com o intuito de prever a formação de grupos em determinadas regiões. Para a realização deste trabalho a rede foi projetada e testada no simulador Ptolemy II, usando o protocolo ZigBee de comunicação, e os sensores foram posicionados de acordo com um sistema de coordenadas cartesianas. A RSSF deverá detectar as pessoas e identificar características comuns de movimento, como velocidade, direção e tipo de movimento, por meio de parâmetros configurados no simulador. As pessoas envolvidas nos grupos serão identificadas por etiquetas RFID (Radio Frequency Identification) presas ao seu corpo. O movimento de multidão teve sua formalização matemática baseada em parâmetros como posição do grupo, quantidade de pessoas por grupo e duração do movimento, que definem as características necessárias para a simulação desse cenário. A partir da formalização do movimento da multidão, vários dados foram coletados em intervalos de tempo previamente determinados e interpretados por um algoritmo que, por meio da troca de mensagens entre sensores, estima a formação de multidão na região definida como alvo. Neste trabalho, foram inseridos tabelas e gráficos que refletem o número real de pessoas que se deslocam em direção ao alvo real. Esses dados foram gerados a partir da intensa troca de mensagens entre os sensores, obedecendo alguns parâmetros estabelecidos e que favorecem o algoritmo que estima a formação de multidão no alvo, em determinado tempo. A acurácia da previsão foi medida pela quantidade de alarmes emitidos e que estimam a formação de aglomerações de pessoas em determinada região. Assim, a detecção de pessoas pelos sensores é interpretada de acordo com a possibilidade de formação de grupos, tendo seus valores disseminados pela rede. A proposta é que essa ação facilite o processo de tomada de decisão e, consequentemente, ajude na caracterização da formação de multidões
228

TU-Spektrum 2/2009, Magazin der Technischen Universität Chemnitz

Steinebach, Mario, Thehos, Katharina, Häckel-Riffler, Christine, Stromer, Anett, Chlebusch, Michael, Rupp, Tanja, Friedrich, Sissy, Michel, Stefanie 24 September 2009 (has links)
dreimal im Jahr erscheinende Zeitschrift über aktuelle Themen der TU Chemnitz
229

TU-Spektrum 2/2009, Magazin der Technischen Universität Chemnitz

Steinebach, Mario, Thehos, Katharina, Häckel-Riffler, Christine, Stromer, Anett, Chlebusch, Michael, Rupp, Tanja, Friedrich, Sissy, Michel, Stefanie 30 October 2009 (has links) (PDF)
dreimal im Jahr erscheinende Zeitschrift über aktuelle Themen der TU Chemnitz
230

Antenne hélice compacte directive à polarisation circulaire pour dispositif RFID / High directivity and circularly polarized low profile helix antenna for RFID devices

Raimbault, Narcisse 19 March 2015 (has links)
La technologie RFID (Radio Frequency Identification) prend une place de plus en plus importante dans la société d'aujourd'hui notamment dans des domaines aussi variés que la santé, la sécurité, la logistique... Le développement de cette technologie met en évidence de nouvelles contraintes comme la réduction des zones de lecture et la géo-localisation pour le stockage et le suivi de marchandises. Dans ce contexte, la thèse s'est focalisée sur le développement d'antennes pour lecteur RFID dans le cadre du projet SPINNAKER piloté par TAGSYS RFID et soutenu par OSEO. L'objectif de cette étude est de concevoir des antennes compactes et directives à polarisation circulaire en bande UHF et SHF. L'antenne hélice présente toutes ces caractéristiques à l'exception de la hauteur, très importante dès que l'on souhaite obtenir des performances élevées surtout en gain. Dans ce manuscrit, trois solutions sont proposées pour réduire la hauteur de l'antenne hélice tout en répondant aux cahiers des charges. La première solution consiste à utiliser un réflecteur de forme cylindrique ou conique qui permet de réduire la hauteur d'une antenne hélice classique d'un facteur quatre pour atteindre 0,9λ. La réduction de la hauteur se traduit par une augmentation de la surface autour de l'antenne avec une dimension latérale de 2,3λ. La seconde solution consiste à utiliser l'antenne hélice avec une cavité Fabry-pérot. La hauteur du système antennaire obtenue est de 0,5λ avec un diamètre de 2λ. La dernière solution développée dans la thèse introduit une surface CMA à la solution précédente qui permet de réduire la hauteur à 0,25λ. Toutes les solutions proposées ont été validées expérimentalement. / Over the past 20 years, the RFID (Radio Frequency Identification) technology is having a huge expansion. Nowadays, it is frequently used in different areas as the health, the security and the logistic. A lot of researches are ongoing on this topic, especially in order to reduce the reading zone of the readers and to locate the tags. This thesis focuses on the development of new antennas for Readers RFID devices and is part of the SPINNAKER project supported by OSEO. The antennas requirements are circular polarization, high directivity and gain with low profile. The helix antennas meet all these requirements except the axial length. In this manuscript, we propose three solutions to reduce the helix antenna axial length. The first one uses a cylindrical or conical optimal reflector to reduce the length by four. This reduction affects directly the surface witch increases up to 2.3λ. The second solution uses the helix antenna as a circular polarization feed for a Fabry-Perot (FP) cavity. The final antenna presents a cavity height of 0.5λ and a 2λ diameter. The last solution conserves the FP cavity in which we include an Artificial Magnetic Conductor (AMC) to reduce the cavity height to 0.25λ. All these solutions are validated by measurements.

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