• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 298
  • 105
  • 94
  • 78
  • 68
  • 55
  • 21
  • 18
  • 18
  • 15
  • 13
  • 9
  • 7
  • 7
  • 5
  • Tagged with
  • 886
  • 164
  • 142
  • 133
  • 127
  • 105
  • 91
  • 79
  • 74
  • 71
  • 70
  • 68
  • 63
  • 62
  • 61
  • 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.
251

Systém pro správu klíčů pomocí RFID / The system for administration keys trough the using RFID

Veselý, Aleš January 2008 (has links)
This thesis dealing with description and system design for administration keys trough the using RFID technology. The main task of this thesis is create a complete controlling algorithms for this system include operating program for platform Windows. Practically output of this thesis is system controlled by microcontroller, which make a decision based on authorisation whether man in question have an accession to the system and which keys he can take.
252

902–928MHz UHF RFID Tag Antenna Design, Fabrication and Test

Kam, Chiweng 01 August 2011 (has links) (PDF)
Radio Frequency Identification (RFID) uses RF radiation to identify physical objects. With decreasing integrated circuit (IC) cost and size, RFID applications are becoming economically feasible and gaining popularity. Researchers at MIT suggest that RFID tags operating in the 900 MHz band (ultrahigh frequency, UHF) represent the best compromise of cost, read range, and capabilities [1]. Passive RFID tags, which exclude radio transmitters and internal power sources, are popular due to their small size and low cost [1]. This project produced Cal Poly’s first ever on-campus printed, assembled, and operational UHF (902 to 928 MHz) passive RFID tag. Project goals include RFID tag antenna design and simulation using the EMPro electromagnetic (EM) simulation tool [47], establishing the tag fabrication process, and testing, operational verification, and comparisons to commercial tag performance. The tag antenna design goal is to meet or exceed the read range performance of the commercial Sirit tag [23] while minimizing the required tag conductive area. This thesis provides an overview of the UHF passive RFID tag fabrication process. Cal Poly’s Graphic Communication Department Laboratory applied a screen‑printing process to print RFID tag antenna patterns onto plastic (PET) substrates. RFID IC-substrate packages were manually attached to tag antennas with conductive adhesives and functionally verified and compared to commercial tag performance. RFID tag antennas were impedance matched (using EMPro) to the Monza 3 RFID IC to maximize IC to antenna power transfer and RFID tag read range.Tag antenna read range (maximum reader-tag communication distance) was characterized in Cal Poly’s Anechoic Chamber, while RFID tag matching characteristics were measured using the differential probe method [33-41] and compared to simulations. Read range results indicate that one of the designs developed in this thesis outperforms a commercial UHF RFID tag.
253

Starker Entwicklungsmotor, aber kein Allheilmittel - Städtische Bibliotheken Dresden

Rabe, Roman 15 July 2010 (has links) (PDF)
Die Städtischen Bibliotheken Dresden sind eine der Stadtbibliotheken mit den höchsten Entleihungen pro Einwohner. Durch den geplanten Umzug der Zentralbibliothek in den Dresdener Kulturpalast wird die RFID-Technik eingeführt. Dadurch erhoffen sich die Städtischen Bibliotheken eine Erweiterung der Öffnungszeiten, eine höhere Nutzerzufriedenheit und natürlich die Gewinnung von Personalkapazität.
254

Starker Entwicklungsmotor, aber kein Allheilmittel - Stadtbibliothek Chemnitz

Müller, Steffi 15 July 2010 (has links) (PDF)
Die Stadtbibliothek Chemnitz setzte das RFID-System 2004 mit dem Neubau der Zentralbibliothek ein. Zusätzlich zu den Transpondern wurden Selbstverbuchungs- und Rückgabeautomaten eingesetzt. Um problemlos auch Medien außerhalb der Öffnungszeiten und aus anderen Teilbibliotheken abzugeben, werden alle neuen Medien mit dem Chip ausgestattet.
255

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.
256

Starker Entwicklungsmotor, aber kein Allheilmittel - Städtische Bibliotheken Dresden: RFID in sächsischen Bibliotheken

Rabe, Roman 15 July 2010 (has links)
Die Städtischen Bibliotheken Dresden sind eine der Stadtbibliotheken mit den höchsten Entleihungen pro Einwohner. Durch den geplanten Umzug der Zentralbibliothek in den Dresdener Kulturpalast wird die RFID-Technik eingeführt. Dadurch erhoffen sich die Städtischen Bibliotheken eine Erweiterung der Öffnungszeiten, eine höhere Nutzerzufriedenheit und natürlich die Gewinnung von Personalkapazität.
257

Starker Entwicklungsmotor, aber kein Allheilmittel - Stadtbibliothek Chemnitz: RFID in sächsischen Bibliotheken

Müller, Steffi 15 July 2010 (has links)
Die Stadtbibliothek Chemnitz setzte das RFID-System 2004 mit dem Neubau der Zentralbibliothek ein. Zusätzlich zu den Transpondern wurden Selbstverbuchungs- und Rückgabeautomaten eingesetzt. Um problemlos auch Medien außerhalb der Öffnungszeiten und aus anderen Teilbibliotheken abzugeben, werden alle neuen Medien mit dem Chip ausgestattet.
258

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. / Petroleum Technology Development Fund (PTDF) and National Space Research and Development Agency (NASRDA).
259

Développement d'un capteur de déformation MEMS sans fil

Merdassi, Adel January 2011 (has links)
Il y a un besoin de mesures de vibration, tel que dans l'automobile pour le contrôle actif du bruit acoustique. Les microsystèmes électromécaniques (MEMS) et les technologies sans fils sont des technologies de plus en plus répandues pour l'implémentation de capteurs. Ce projet vise donc le développement de capteurs de déformation en utilisant une solution sans fil pour l'acquisition des mesures de la vibration, avec les technologies MEMS. Ce projet de recherche utilise la technologie des systèmes RFID passifs pour la communication, intégrée avec un transducteur de déformation MEMS pour la mesure. Le capteur consiste en une antenne reliée à un transducteur MEMS capacitif par l'entremise d'une ligne de transmission avec des discontinuités. Les déformations de la structure sur laquelle le capteur est fixé sont traduites en changement de capacité du transducteur, ce qui engendre un retard dans le signal réfléchi par l'antenne. Une étude de l'état de l'art des principes de communication et de transduction a permis de comparer les avantages et inconvénients des approches. Une modélisation analytique faite sur différents types de transduction a conduit à une combinaison optimale faisant intervenir un transducteur type capacitif. Pour atteindre une taille du capteur de l'ordre du centimètre, le système travaille à une fréquence micro-onde fixée à 24,125 GHz. Un dispositif fût alors conçu, incluant la ligne de transmission avec des discontinuités pour l'identification du capteur ainsi que le transducteur capacitif avec peignes interdigités et ressorts en silicium. La conception d'un tel capteur permet d'aboutir à une sensibilité de 11ps/[epsilon] avec une bonne linéarité sur une plage de mesure [0..2500[micro][epsilon]]. Un procédé de microfabrication du transducteur MEMS est aussi proposé, ainsi qu'une approche pour la fabrication pour les éléments RF sur un substrat d'alumine et leur intégration.
260

Konsumentens möte med teknologi i butik : Den digitaliserade köpprocessen

Falck, Ewelina, Nordström, Klara January 2016 (has links)
Konsumenter födda i generation Y är mer digitalt kompetenta i jämförelse med tidigare generationer. De har växt upp i takt med teknologins utveckling och ser inga hinder med att använda den. Denna studie behandlar därför hur olika teknologiska lösningar kan användas i fysiska modebutiker för att undersöka hur detta påverkar konsumenternas köpprocess. Personlig service utgörs vanligtvis av att personalen tar kontakt med en konsument och riktar sin uppmärksamhet gentemot denne och försöker få personen i fråga att fullfölja köpprocessen. Med olika teknologiska lösningar tillåts konsumenter däremot att genomföra denna köpprocess mer självständigt och därför har denna studie även ett serviceperspektiv där vi undersöker hur den personliga servicen förändras av teknologins inverkan. Den teknologi som specifikt har undersökts har bestått av RFID- och NFC- tekniker via pekskärmar i provrum och betalstationer. Vidare har studien innefattat dels hur konsumenter upplever dessa typer av teknologier i en fysisk modebutik och dels hur konsumenter vill erhålla personlig service. Detta har gjorts genom en enkätundersökning via Internet och en kundundersökning med intervjuer i en labbmiljö. Vårt resultat visar att konsumenterna upplever teknologin som ett uppskattat och underlättande verktyg i köpprocessen då de föredrar att genomföra köp på ett effektivt sätt och på egen hand. Fortsättningsvis ser vi att konsumenterna efterfrågar en personlig service men däremot önskas överhuvudtaget ingen mänsklig kontakt med personalen i butik.Engelsk titel (kopiera från uppsats) *: Consumer´s meeting with technology in storesEngelska nyckelord *: Technology, RFID, NFC, Omni, In-store, Buying Process, Personalized ServiceSustainable development anges som nyckelord på engelska?: NEJEngelsk sammanfattning *: Consumers born in generation Y are more digitally literate than people born in previous generations. They have grown up in pace with the development of technology and sees no obstacles with using it. This study therefore addresses how technological solutions can be used in physical fashion stores to investigate how this affects the consumer´s buying process. Personalized service usually consists of that the staff will contact a consumer and direct her attention towards the costumer in attempt to complete their buying process. With different technological solutions the consumer is allowed to perform this process more independently and therefore this study also holds a service perspective, where we examine how the personalized service is affected by the technology´s impact. The technologies that have been studied specifically consisted of RFID and NFC technologies via touch screens in fitting rooms and pay stations. Furthermore, this study includes both how consumers experience these types of technologies in a physical fashion store and also how consumers want to receive personalized service. This has been done through a survey via the Internet and through a customer survey with interviews in a lab environment. Our results show that consumers perceive the technology as a valued and facilitative tool in the buying process since they prefer to make purchases in an efficient way and by their selves. Henceforth, we can see that consumers want a personalized service but no human contact at all is desired with the staff in the fashion store.

Page generated in 0.0447 seconds