760 research outputs found

    An MILP-Based Cross-Layer Optimization for a Multi-Reader Arbitration in the UHF RFID System

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    In RFID systems, the performance of each reader such as interrogation range and tag recognition rate may suffer from interferences from other readers. Since the reader interference can be mitigated by output signal power control, spectral and/or temporal separation among readers, the system performance depends on how to adapt the various reader arbitration metrics such as time, frequency, and output power to the system environment. However, complexity and difficulty of the optimization problem increase with respect to the variety of the arbitration metrics. Thus, most proposals in previous study have been suggested to primarily prevent the reader collision with consideration of one or two arbitration metrics. In this paper, we propose a novel cross-layer optimization design based on the concept of combining time division, frequency division, and power control not only to solve the reader interference problem, but also to achieve the multiple objectives such as minimum interrogation delay, maximum reader utilization, and energy efficiency. Based on the priority of the multiple objectives, our cross-layer design optimizes the system sequentially by means of the mixed-integer linear programming. In spite of the multi-stage optimization, the optimization design is formulated as a concise single mathematical form by properly assigning a weight to each objective. Numerical results demonstrate the effectiveness of the proposed optimization design

    A Review on Missing Tags Detection Approaches in RFID System

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    Radio Frequency Identification (RFID) system can provides automatic detection on very large number of tagged objects within short time. With this advantage, it is been using in many areas especially in the supply chain management, manufacturing and many others. It has the ability to track individual object all away from the manufacturing factory until it reach the retailer store. However, due to its nature that depends on radio signal to do the detection, reading on tagged objects can be missing due to the signal lost. The signal lost can be caused by weak signal, interference and unknown source. Missing tag detection in RFID system is truly significant problem, because it makes system reporting becoming useless, due to the misleading information generated from the inaccurate readings. The missing detection also can invoke fake alarm on theft, or object left undetected and unattended for some period. This paper provides review regarding this issue and compares some of the proposed approaches including Window Sub-range Transition Detection (WSTD), Efficient Missing-Tag Detection Protocol (EMD) and Multi-hashing based Missing Tag Identification (MMTI) protocol. Based on the reviews it will give insight on the current challenges and open up for a new solution in solving the problem of missing tag detection

    Advances in analytical models and applications for RFID, WSN and AmI systems

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    Experimentos llevados a cabo con el equipo de división de honor UCAM Volleyball Murcia.[SPA] Internet de las cosas (IoT) integra distintos elementos que actúan tanto como fuentes, como sumideros de información, a diferencia de la percepción que se ha tenido hasta ahora de Internet, centrado en las personas. Los avances en IoT engloban un amplio número de áreas y tecnologías, desde la adquisición de información hasta el desarrollo de nuevos protocolos y aplicaciones. Un concepto clave que subyace en el concepto de IoT, es el procesamiento de forma inteligente y autónoma de los flujos de información que se dispone. En este trabajo, estudiamos tres aspectos diferentes de IoT. En primer lugar, nos centraremos en la infraestructura de obtención de datos. Entre las diferentes tecnologías de obtención de datos disponibles en los sistemas IoT, la Identificación por Radio Frecuencia (RFID) es considerada como una de las tecnologías predominantes. RFID es la tecnología detrás de aplicaciones tales como control de acceso, seguimiento y rastreo de contenedores, gestión de archivos, clasificación de equipaje o localización de equipos. Con el auge de la tecnología RFID, muchas instalaciones empiezan a requerir la presencia de múltiples lectores RFID que operan próximos entre sí y conjuntamente. A estos escenarios se les conoce como dense reader environments (DREs). La coexistencia de varios lectores operando simultáneamente puede causar graves problemas de interferencias en el proceso de identificación. Uno de los aspectos claves a resolver en los RFID DREs consiste en lograr la coordinación entre los lectores. Estos problemas de coordinación son tratados en detalle en esta tesis doctoral. Además, dentro del área de obtención de datos relativa a IoT, las Redes de Sensores Inalámbricas (WSNs) desempeñan un papel fundamental. Durante la última década, las WSNs han sido estudiadas ampliamente de forma teórica, y la mayoría de problemas relacionados con la comunicación en este tipo de redes se han conseguido resolver de forma favorable. Sin embargo, con la implementación de WSNs en proyectos reales, han surgido nuevos problemas, siendo uno de ellos el desarrollo de estrategias realistas para desplegar las WSN. En este trabajo se estudian diferentes métodos que resuelven este problema, centrándonos en distintos criterios de optimización, y analizando las diferentes ventajas e inconvenientes que se producen al buscar una solución equilibrada. Por último, la Inteligencia Ambiental (AmI) forma parte del desarrollo de aplicaciones inteligentes en IoT. Hasta ahora, han sido las personas quienes han tenido que adaptarse al entorno, en cambio, AmI persigue crear entornos de obtención de datos capaces de anticipar y apoyar las acciones de las personas. AmI se está introduciendo progresivamente en diversos entornos reales tales como el sector de la educación y la salud, en viviendas, etc. En esta tesis se introduce un sistema AmI orientado al deporte que busca mejorar el entrenamiento de los atletas, siendo el objetivo prioritario el desarrollo de un asistente capaz de proporcionar órdenes de entrenamiento, basadas tanto en el entorno como en el rendimiento de los atletas. [ENG] Internet of Things (IoT) is being built upon many different elements acting as sources and sinks of information, rather than the previous human-centric Internet conception. Developments in IoT include a vast set of fields ranging from data sensing, to development of new protocols and applications. Indeed, a key concept underlying in the conception of IoT is the smart and autonomous processing of the new huge data flows available. In this work, we aim to study three different aspects within IoT. First, we will focus on the sensing infrastructure. Among the different kind of sensing technologies available to IoT systems, Radio Frequency Identification (RFID) is widely considered one of the leading technologies. RFID is the enabling technology behind applications such as access control, tracking and tracing of containers, file management, baggage sorting or equipment location. With the grow up of RFID, many facilities require multiple RFID readers usually operating close to each other. These are known as Dense Reader Environments (DREs). The co-existence of several readers operating concurrently is known to cause severe interferences on the identification process. One of the key aspects to solve in RFID DREs is achieving proper coordination among readers. This is the focus of the first part of this doctoral thesis. Unlike previous works based on heuristics, we address this problem through an optimization-based approach. The goal is identifying the maximum mean number of tags while network constraints are met. To be able to formulate these optimization problems, we have obtained analytically the mean number of identifications in a bounded -discrete or continuous- time period, an additional novel contribution of our work. Results show that our approach is overwhelmingly better than previous known methods. Along sensing technologies of IoT, Wireless Sensor Networks (WSNs) plays a fundamental role. WSNs have been largely and theoretically studied in the past decade, and many of their initial problems related to communication aspects have been successfully solved. However, with the adoption of WSNs in real-life projects, new issues have arisen, being one of them the development of realistic strategies to deploy WSNs. We have studied different ways of solving this aspect by focusing on different optimality criteria and evaluating the different trade-offs that occur when a balanced solution must be selected. On the one hand, deterministic placements subject to conflicting goals have been addressed. Results can be obtained in the form of Pareto-frontiers, allowing proper solution selection. On the other hand, a number of situations correspond to deployments were the nodes¿ position is inherently random. We have analyzed these situations leading first to a theoretical model, which later has been particularized to a Moon WSN survey. Our work is the first considering a full model with realistic properties such as 3D topography, propellant consumptions or network lifetime and mass limitations. Furthermore, development of smart applications within IoT is the focus of the Ambient Intelligence (AmI) field. Rather than having people adapting to the surrounding environment, AmI pursues the development of sensitive environments able to anticipate support in people¿s actions. AmI is progressively being introduced in many real-life environments like education, homes, health and so forth. In this thesis we develop a sport-oriented AmI system designed to improve athletes training. The goal is developing an assistant able to provide real-time training orders based on both environment and athletes¿ biometry, which is aimed to control the aerobic and the technical-tactical training. Validation experiments with the honor league UCAM Volleyball Murcia team have shown the suitability of this approach.[ENG] Internet of Things (IoT) is being built upon many different elements acting as sources and sinks of information, rather than the previous human-centric Internet conception. Developments in IoT include a vast set of fields ranging from data sensing, to development of new protocols and applications. Indeed, a key concept underlying in the conception of IoT is the smart and autonomous processing of the new huge data flows available. In this work, we aim to study three different aspects within IoT. First, we will focus on the sensing infrastructure. Among the different kind of sensing technologies available to IoT systems, Radio Frequency Identification (RFID) is widely considered one of the leading technologies. RFID is the enabling technology behind applications such as access control, tracking and tracing of containers, file management, baggage sorting or equipment location. With the grow up of RFID, many facilities require multiple RFID readers usually operating close to each other. These are known as Dense Reader Environments (DREs). The co-existence of several readers operating concurrently is known to cause severe interferences on the identification process. One of the key aspects to solve in RFID DREs is achieving proper coordination among readers. This is the focus of the first part of this doctoral thesis. Unlike previous works based on heuristics, we address this problem through an optimization-based approach. The goal is identifying the maximum mean number of tags while network constraints are met. To be able to formulate these optimization problems, we have obtained analytically the mean number of identifications in a bounded -discrete or continuous- time period, an additional novel contribution of our work. Results show that our approach is overwhelmingly better than previous known methods. Along sensing technologies of IoT, Wireless Sensor Networks (WSNs) plays a fundamental role. WSNs have been largely and theoretically studied in the past decade, and many of their initial problems related to communication aspects have been successfully solved. However, with the adoption of WSNs in real-life projects, new issues have arisen, being one of them the development of realistic strategies to deploy WSNs. We have studied different ways of solving this aspect by focusing on different optimality criteria and evaluating the different trade-offs that occur when a balanced solution must be selected. On the one hand, deterministic placements subject to conflicting goals have been addressed. Results can be obtained in the form of Pareto-frontiers, allowing proper solution selection. On the other hand, a number of situations correspond to deployments were the nodes¿ position is inherently random. We have analyzed these situations leading first to a theoretical model, which later has been particularized to a Moon WSN survey. Our work is the first considering a full model with realistic properties such as 3D topography, propellant consumptions or network lifetime and mass limitations. Furthermore, development of smart applications within IoT is the focus of the Ambient Intelligence (AmI) field. Rather than having people adapting to the surrounding environment, AmI pursues the development of sensitive environments able to anticipate support in people¿s actions. AmI is progressively being introduced in many real-life environments like education, homes, health and so forth. In this thesis we develop a sport-oriented AmI system designed to improve athletes training. The goal is developing an assistant able to provide real-time training orders based on both environment and athletes¿ biometry, which is aimed to control the aerobic and the technical-tactical training. Validation experiments with the honor league UCAM Volleyball Murcia team have shown the suitability of this approach.Universidad Politécnica de CartagenaPrograma de doctorado en Tecnología de la Información y de las Comunicacione

    Reliable Communication in Wireless Networks

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    Wireless communication systems are increasingly being used in industries and infrastructures since they offer significant advantages such as cost effectiveness and scalability with respect to wired communication system. However, the broadcast feature and the unreliable links in the wireless communication system may cause more communication collisions and redundant transmissions. Consequently, guaranteeing reliable and efficient transmission in wireless communication systems has become a big challenging issue. In particular, analysis and evaluation of reliable transmission protocols in wireless sensor networks (WSNs) and radio frequency identification system (RFID) are strongly required. This thesis proposes to model, analyze and evaluate self-configuration algorithms in wireless communication systems. The objective is to propose innovative solutions for communication protocols in WSNs and RFID systems, aiming at optimizing the performance of the algorithms in terms of throughput, reliability and power consumption. The first activity focuses on communication protocols in WSNs, which have been investigated, evaluated and optimized, in order to ensure fast and reliable data transmission between sensor nodes. The second research topic addresses the interference problem in RFID systems. The target is to evaluate and develop precise models for accurately describing the interference among readers. Based on these models, new solutions for reducing collision in RFID systems have been investigated

    An Approach for Removing Redundant Data from RFID Data Streams

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    Radio frequency identification (RFID) systems are emerging as the primary object identification mechanism, especially in supply chain management. However, RFID naturally generates a large amount of duplicate readings. Removing these duplicates from the RFID data stream is paramount as it does not contribute new information to the system and wastes system resources. Existing approaches to deal with this problem cannot fulfill the real time demands to process the massive RFID data stream. We propose a data filtering approach that efficiently detects and removes duplicate readings from RFID data streams. Experimental results show that the proposed approach offers a significant improvement as compared to the existing approaches

    Building efficient wireless infrastructures for pervasive computing environments

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    Pervasive computing is an emerging concept that thoroughly brings computing devices and the consequent technology into people\u27s daily life and activities. Most of these computing devices are very small, sometimes even invisible , and often embedded into the objects surrounding people. In addition, these devices usually are not isolated, but networked with each other through wireless channels so that people can easily control and access them. In the architecture of pervasive computing systems, these small and networked computing devices form a wireless infrastructure layer to support various functionalities in the upper application layer.;In practical applications, the wireless infrastructure often plays a role of data provider in a query/reply model, i.e., applications issue a query requesting certain data and the underlying wireless infrastructure is responsible for replying to the query. This dissertation has focused on the most critical issue of efficiency in designing such a wireless infrastructure. In particular, our problem resides in two domains depending on different definitions of efficiency. The first definition is time efficiency, i.e., how quickly a query can be replied. Many applications, especially real-time applications, require prompt response to a query as the consequent operations may be affected by the prior delay. The second definition is energy efficiency which is extremely important for the pervasive computing devices powered by batteries. Above all, our design goal is to reply to a query from applications quickly and with low energy cost.;This dissertation has investigated two representative wireless infrastructures, sensor networks and RFID systems, both of which can serve applications with useful information about the environments. We have comprehensively explored various important and representative problems from both algorithmic and experimental perspectives including efficient network architecture design and efficient protocols for basic queries and complicated data mining queries. The major design challenges of achieving efficiency are the massive amount of data involved in a query and the extremely limited resources and capability each small device possesses. We have proposed novel and efficient solutions with intensive evaluation. Compared to the prior work, this dissertation has identified a few important new problems and the proposed solutions significantly improve the performance in terms of time efficiency and energy efficiency. Our work also provides referrable insights and appropriate methodology to other similar problems in the research community

    Evaluation of a UHF RFID system for livestock

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    A structural change could be observed within German animal production in recent years. Whereas the number of livestock holdings decreased, the number of animals per livestock holding increased. Because bigger livestock holdings are also often in a conflict of aims between sustainability, animal welfare and economy, a well-functioning and cost-effective management assistance is even more important. The collection of animal-related data and data from their environment with simple, innovative and low-cost techniques to improve animal welfare, animal health and animal performance, as well as the housing conditions, is a main part of so-called precision livestock farming (PLF). A possible solution for implementation of these thoughts is a technology called radio-frequency identification (RFID). The suitability of an UHF RFID system for simultaneous pig and cattle detection could be evaluated during a three year project, which was funded by the Federal Office of Agriculture and Food. Therefore, several UHF transponder ear tags had to be developed and tested in laboratory and practical experiments. Additionally, a cost-benefit analysis of the UHF system based on four example barns had to be carried out to estimate the potential of the system for use in practice. Thereby, not only the costs and benefits of simultaneous animal detection were calculated, but also the costs and benefits of hotspot monitoring of the animals in their husbandry environment were estimated. Nine different transponder types for each animal species were developed within the duration of the project. During the development process, the antenna structure, antenna length and label material had to be varied to adjust the transponder to its immediate surroundings as optimally as possible. The grouting process of the transponder into the ear tag was also continuously improved. Before testing the UHF transponder ear tag types in practice, they were all tested on a dynamic test bench. Using this test bench, a preliminarily assessment of the in-house developed transponder types by themselves, with foreign and commercially available UHF transponder types under various conditions was possible. The number of readings per round was recorded and used to identify differences between the transponder types. The UHF transponder ear tag types were tested with the aid of driving experiments using pigs and cattle with a focus on their suitability and durability under practical conditions. While one gate in a stall environment was built in the driving experiments for the fattening pigs, with cattle, reader output power, reader orientation and the test environment were varied. In these experiments, the number of readings per round and the reading rates, which were the more decisive value in practice, were calculated. In the last stage of development, a suitable, well-functioning UHF transponder ear tag type and good average reading rates could be achieved for both animal species (pigs: ø 98 %; cattle: ø 99 %) While performing the cost-benefit analysis, it could be calculated that, at the present state of development of the UHF system, the benefits do not exceed the costs of the system in the fattening pig husbandry. In dairy cattle husbandry, a positive result could be reached only under the best estimations and the larger farm. However, the costs arising per animal are still too high to implement the systems on the market. Because of the early stage of development, the calculation of the costs and benefits was difficult and still holds uncertainties. Following the assumption that the UHF system will be developed to practical maturity, the costs calculated would be lower and an advantageousness of the system would be also expected for other farms. This work was sensible and necessary to get a first assessment of the costs and benefits. Great development progress could be achieved for the UHF RFID system and a large potential for PLF could be shown within this project, even if the system is not yet ready for market.Innerhalb der deutschen Tierproduktion konnte in den vergangenen Jahren ein Strukturwandel festgestellt werden. Während die Anzahl der landwirtschaftlichen Betriebe stetig sank, nahm die Anzahl an Tieren pro Betrieb zu. Da jedoch auch große tierhaltende landwirtschaftliche Betriebe häufig im Zielkonflikt zwischen Nachhaltigkeit, Tiergerechtheit und Wirtschaftlichkeit stehen, ist eine gut funktionierende und kostengünstige Managementhilfe umso wichtiger. Das Sammeln von tier- und umweltbezogenen Daten mit einfachen, innovativen und günstigen Techniken zur Verbesserung von Tierwohl, -gesundheit und -leistung sowie Haltungsbedingungen, stellt den hauptsächlichen Teil des sogenannten Precision Livestock Farming (PLF) dar. Eine Möglichkeit zur technischen Umsetzung stellt die sogenannte Radiofrequenzidentifikation dar (RFID). Während eines dreijährigen, von der Bundesanstalt für Landwirtschaft und Ernährung finanzierten, Verbundprojektes wurde die Eignung eines UHF-RFID-Systems zur Simultanerfassung von Schweinen und Rindern getestet und bewertet. Hierfür wurden verschiedenste UHF-Transponderohrmarken entwickelt, an Prüfständen und in Praxisanwendungen getestet. Zusätzlich wurde eine Kosten-Nutzen-Analyse des UHF-RFID-Systems anhand von vier Beispielställen durchgeführt um das Potential des Systems für den Einsatz in der Praxis abzuschätzen. Hierfür wurden nicht nur die Kosten und der Nutzen des Systems zur simultanen Tiererfassung berücksichtigt, sondern auch eine Überwachung der Tiere an verschiedensten Punkten ihrer Haltungsumwelt. In der gesamten Projektlaufzeit wurden für beide Tierarten neun unterschiedliche Transpondertypen entwickelt. Während des Entwicklungsprozesses wurden die Antennenstruktur, -länge und das Trägermaterial des Transponders verändert und somit der Transponder an seine unmittelbare Umgebung so gut wie möglich angepasst. Auch der Prozess des Eingießens wurde stetig verbessert. Bevor die UHF-Transponderohrmarken in der Praxis getestet wurden, wurden sie auf einem dynamischen Prüfstand beurteilt, sowie mit anderen eigens entwickelten, projektfremden und kommerziell erhältlichen UHF-Transponderohrmarken unter verschiedenen Bedingungen verglichen. Es wurde die Anzahl an Lesungen pro Runde aufgenommen um Unterschiede zwischen den Transpondertypen festzustellen. Mit Hilfe von Treibeversuchen an Schweinen und Rindern wurde die Eignung und Haltbarkeit der Transponderohrmarken in der Praxis untersucht. Während für die Versuche mit Schweinen ein Lesegerätgate, mit in allen Versuchen gleichen Einstellungen, im Stall aufgebaut wurde, wurden bei den Rindern die Lesegerätleistung, die Lesegerätausrichtung und die Versuchsumgebung variiert. Bei diesen Experimenten wurden sowohl die Anzahl an Lesungen pro Runde als auch die Erfassungsquoten, welche den für die praktische Anwendung wichtigeren Wert darstellen, berechnet. Mit dem letzten Entwicklungsschritt konnte eine funktionsfähige und haltbare UHF-Transponderohrmarke mit guten durchschnittlichen Erfassungsquoten für beide Tierarten entwickelt werden (Schwein: ø 98 %; Rind: ø 99 %). Bei der Durchführung der Kosten-Nutzen-Analyse konnte gezeigt werden, dass, zum jetzigen Entwicklungszeitpunkt des Systems, der Nutzen die Kosten im Bereich der Mastschweinehaltung nicht übersteigt. In der Milchviehhaltung konnte nur unter den günstigsten Annahmen und für den größten Betrieb ein positives Ergebnis erzielt werden. Die entstehenden Kosten pro Tier sind vermutlich jedoch zu hoch für die Etablierung des Systems auf dem Markt. Allerdings war, aufgrund des frühen Entwicklungsstadiums des Systems, eine Kosten- und Nutzenabschätzung des Systems schwierig und ist mit Unsicherheiten behaftet. Unter der Voraussetzung der Praxistauglichkeit des Systems würden die Kosten sinken und auch für andere Betriebe ließe sich eine Vorteilhaftigkeit des Systems erwarten. Die vorliegende Arbeit war sinnvoll und wichtig um eine erste Beurteilung der Kosten und Nutzen des Systems zu bekommen. Innerhalb des Projektes konnte ein großer Entwicklungsfortschritt des UHF-RFID-Systems erreicht und das große Potential für PLF gezeigt werden, auch wenn das System bis jetzt noch nicht marktreif ist

    RFID Reader for 13.56 MHz Band

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    Cieľom tejto práce je navrhnúť RFID čítačku pre pásmo 13.56 MHz a zostaviť k nej riadiaci program. V prvej časti je najskôr práca smerovaná k oboznámeniu sa s princípom fungovania technológií RFID a NFC, spolu s tým súvisiacimi medzinárodnými štandardami a k oboznámeniu sa s rôznymi dostupnými čipmi na obsluhu týchto technológií. Keďže čip s ktorým sa bude pokračovať je jasne zadaný v návode, ich porovnanie slúži čisto oboznamovaciemu účelu. V praktickej časti je úloha navrhnúť a oživiť prototyp RFID čítačky. Základom je doska sprostredkúvajúca RFID komunikáciu, audiovizuálnu odozvu a pripojenie k OLED displeju. Táto doska je pripojená na mikrokontrolér na ktorý riadi celé ovládanie zariadenia. Súčasťou projektu je aj set rôznych antén, ktoré je možné na dosku pripojiť a zároveň ich vymieňať. Vyrobené antény sú podrobené testovaniu ako dve rozdielne metódy ladenia ovplyvnia ich chod. Testujú sa maximálna vzdialenosť čítania, úspech prevedených čítaní a hodnota prúdu, ktorá sa vznesie pri kalibračnom procese. Výstupom práce je RFID čítač s riadiacim programom.The aim of this thesis is to design an RFID reader for the 13.56 MHz band and to compile a control program. In the first part, the work is aimed at getting acquainted with the principle of operation of RFID and NFC technologies, together with the related international standard, and at getting familiarized with the various transceivers available to operate these technologies. Because the transceiver for the further evaluation is clearly specified in the assignment, their comparison serves a purely informational purpose. In the practical part, the task is to design and revive a prototype RFID reader. The base of the project is a reader board carrying out RFID communication, audiovisual response, and connection to an OLED display. This board is connected to a microcontroller, which controls the whole device. Another part of the project is set of different antennas that can be connected to the reader board and replaced at any time. The manufactured antennas are subject to a testing of how two different tuning methods affect their operation. The maximum reading distance, success of the performed readings and value of the electrical current that is a result of the calibration process are being tested. The output of the thesis is an RFID reader with a control program.
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