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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

Modeling, Analysis, and Efficient Resource Allocation in Cyber-Physical Systems and Critical Infrastructure Networks

January 2016 (has links)
abstract: The critical infrastructures of the nation are a large and complex network of human, physical and cyber-physical systems. In recent times, it has become increasingly apparent that individual critical infrastructures, such as the power and communication networks, do not operate in isolation, but instead are part of a complex interdependent ecosystem where a failure involving a small set of network entities can trigger a cascading event resulting in the failure of a much larger set of entities through the failure propagation process. Recognizing the need for a deeper understanding of the interdependent relationships between such critical infrastructures, several models have been proposed and analyzed in the last few years. However, most of these models are over-simplified and fail to capture the complex interdependencies that may exist between critical infrastructures. To overcome the limitations of existing models, this dissertation presents a new model -- the Implicative Interdependency Model (IIM) that is able to capture such complex interdependency relations. As the potential for a failure cascade in critical interdependent networks poses several risks that can jeopardize the nation, this dissertation explores relevant research problems in the interdependent power and communication networks using the proposed IIM and lays the foundations for further study using this model. Apart from exploring problems in interdependent critical infrastructures, this dissertation also explores resource allocation techniques for environments enabled with cyber-physical systems. Specifically, the problem of efficient path planning for data collection using mobile cyber-physical systems is explored. Two such environments are considered: a Radio-Frequency IDentification (RFID) environment with mobile “Tags” and “Readers”, and a sensor data collection environment where both the sensors and the data mules (data collectors) are mobile. Finally, from an applied research perspective, this dissertation presents Raptor, an advanced network planning and management tool for mitigating the impact of spatially correlated, or region based faults on infrastructure networks. Raptor consolidates a wide range of studies conducted in the last few years on region based faults, and provides an interface for network planners, designers and operators to use the results of these studies for designing robust and resilient networks in the presence of spatially correlated faults. / Dissertation/Thesis / Doctoral Dissertation Computer Science 2016
22

RFID Emergency System for Tumble Detection of Solitary People

Ge, Quanyi, Chai, Yi January 2012 (has links)
RFID (Radio Frequency Identification) system is a wireless system without any kinds of mechanical or optical connection between identifying and detected objects. It consists of two basic devices: a reader and tag. Recently with the development of the technology, SAW-RFID (Surface Acoustic Wave Radio Frequency Identification) tags come into market with acceptable price, as well as its size tends to miniaturization. We propose to use 3D wireless indoor localization system to detect the position of the tags. The reader converts radio waves returned from the SAW-RFID tag into a form, which can be useful to process the information. The system consists of SAW-RFID tags placed on the object and several RF Readers in the room. The readers sequentially transmit the impulse signals which are then reflected from different tags and received by readers. Then a signal round-trip TOA (Time of Arrival) between tags and readers can be estimated. We define a 3D coordinate system of the readers and calculate the positions of the tags using suitable specific algorithm. Our system is design to monitor a human body position. The goal is to detect a tumble of solitary living people. A case when the tag positions are identified to be below a per-set threshold means that something happened, and maybe a man has fallen on the ground. This emergency situation can be detected by the monitoring system which then sends information to an alarm system which can call the health centre to take care of the patient. In this paper, a 5 m×5 m×3 m indoor localization system is implemented in Matlab. The simulation results show a correct identification of a fallen man and accuracy of the high measurement below 30 cm. / 0762770008
23

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.
24

Conception d’antennes et méthode de caractérisation des systèmes RFID UHF en champ proche et en champ lointain / Antenna design and characterization method of near-field and far-field UHF RFID systems

Souza, Aline Coelho de 07 October 2015 (has links)
La technologie d'identification par radiofréquence (RFID) a eu un essor très important ces dernières années notamment grâce à sa configuration polyvalente et aux innombrables possibilités d'intégration offertes par cette technologie notamment avec l'apparition d'un nouveau contexte applicatif celui des objets connectés. Depuis quelques années, des applications de la RFID UHF en champ proche ont été notamment développées afin de surmonter les problèmes liés à la dégradation de lecture des tags lorsqu'ils sont placés dans des milieux fortement perturbateurs. Les travaux de recherche présentés dans cette thèse s'intéressent à l'étude de la technologie RFID UHF en zones de champ proche et de champ lointain. Les études portent plus particulièrement sur la conception d'antennes lecteur et d'antennes tag ainsi que sur les méthodes de caractérisation des systèmes RFID en zones de champ proche et de champ lointain. Une étude sur les caractéristiques des champs rayonnées par une antenne est réalisée afin de souligner les critères les plus pertinents en vue de concevoir des antennes pour les lecteurs RFID, performantes en zone de champ proche. A partir de l'état de l'art sur les antennes tags et les méthodologies de conception classiques, une nouvelle approche de conception est développée qui vise à améliorer la conception d'antennes tags en intégrant une vision appropriée pour tenir compte du niveau de puissance espéré dans une application donnée. Enfin avec pour objectif la caractérisation des tags RFID UHF, d'une part une approche est proposée permettant l'identification de familles de tags, et d'autre part, une procédure innovante pour la mesure de l'efficacité du transfert de puissance est proposée et validée expérimentalement. / The Radiofrequency Identification technology (RFID) has had a huge growth these last years, due to its versatility and the uncountable possibilities to integrate this technology in many different application (tracking and inventory of goods, access control, supply chain, etc.), and in particular the brand new context of internet of things projects. For some years, the near field UHF RFID applications has been developed in order to overcome the problems related to degradations of tag's read range when needing to use it in a perturbing environment. The research work presented in this thesis come as a study of the UHF RFID in near field and far field zones. This study focus more particularly on the design of reader and tag antennas and on the characterization method in near field and far field zones. A study on the characteristics of fields outgoing from an antenna has been made, in order to underline the important criteria for the design of performant UHF RFID reader antennas in near field zone. From the state of art about tag antennas design and classical methodologies, we propose a new approach that aims improving the design of tag antennas in a more suitable point of view that is getting the expected power level in a given application. Finally, with an objective to characterize UHF RFID tags, we first propose a new approach enabling the identification of tag families, and then propose a new innovating power transfer efficiency measurement procedure, that has been validated experimentally.

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