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Multilink para determina??o da taxa de ocupa??o em ambientes internos utilizando uma rede de sensores sem fioFaria, Thiago Tortorelli de 23 June 2015 (has links)
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Previous issue date: 2015-06-23 / This work aims to obtain a mathematical model to determinate the occupancy rate in indoor environment based on signal strength of a wireless sensor network (WSN) in 915 MHz using four links at the environment. It was set a network with one sink and four node sensors in a laboratory in order to collect the RSSI (Received Signal Strength Indication) of each individual link for every different space occupation for each group of people. Based on the data collected, it was calculated the mean, standard deviation and the variance of each individual link and the overall average of links for each group of people. The data was used as input in mathematical models to determine the occupancy rate of the environment. Three mathematical models have been proposed to estimate the occupancy rate. All of them proved capable to estimate the number of people using the overall average of links. The results showed that the tendency is to decrease the RSSI and increase the standard deviation the greater the number of people in the environment. Some links analyzed individually showed a large variation and not following entirely the tendency mentioned. Nevertheless the overall average of links follows this tendency showing that despite a link shows a great variation, the other links tended to compensate this variation and with the overall average of links is possible to get a small error between the real number of people and the estimated number of people. To choose the best model it was used the MAE (Mean Absolute Error). The second order model was the best model with a MAE slightly below of a half people. The results obtained using multilink were compared with a work that used single-link to predict the number of people in a indoor environment. Multilink had a smaller error compared with single-link, which obtained an error of about two people. / Este trabalho tem por objetivo a obten??o de um modelo matem?tico para a determina??o da taxa de ocupa??o de ambientes internos baseado na intensidade de sinal de uma Rede de Sensores sem Fio em 915 MHz utilizando quatro links r?dio no ambiente. Foi montada uma rede com uma base e quatro n?s sensores em um laborat?rio como intuito de coletar a RSSI (Received Signal Strenght Indication) de cada link para cada diferente ocupa??o do espa?o para cada grupo de pessoas. Com base nos dados coletados, foram calculados a m?dia, desvio padr?o e vari?ncia de cada link e cada grupo de pessoas. Esses dados foram utilizados como entrada em modelos matem?ticos para a determina??o da taxa de ocupa??o do ambiente. Foram propostos tr?s modelos matem?ticos para tal estima??o. Os tr?s modelos se mostraram aptos a estimar o n?mero de pessoas utilizando a m?dia geral dos links. Os resultados iniciais mostraram que a tend?ncia ? de diminui??o da RSSI e o aumento do desvio padr?o quanto maior o n?mero de pessoas no ambiente. Alguns links analisados de forma individual se mostraram com uma varia??o grande e n?o seguindo inteiramente a tend?ncia mencionada, mas apesar disso a m?dia geral dos links segue essa tend?ncia, ou seja, apesar de um link demonstrar uma grande varia??o, os outros links tenderam a compensar essa varia??o. Com a m?dia geral ? poss?vel chegar a um erro pequeno entre o n?mero real de pessoas e o n?mero estimado de pessoas. Para a escolha do melhor modelo foi utilizado o RAM (Res?duo Absoluto M?dio) e para a m?dia geral dos links o modelo de segunda ordem foi o que se mostrou melhor com um res?duo abaixo de meia pessoa. Por fim os resultados obtidos com multilink foram comparados com resultados obtidos em um trabalho em que foi utilizado single-link para a obten??o da taxa de ocupa??o em um ambiente interno. Multilink, com um RAM de aproximadamente 0,5 pessoas, se mostrou com um erro menor comparado com o single-link, que obteve um erro de aproximadamente duas pessoas.
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Estimativa da PER, protocolo de coleta de RSSI e determina??o de melhores rotas em RSSF / Estimate PER, protocol for RSSI collection and determination of best routesPereira, Vitor Queiroz 23 June 2016 (has links)
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Previous issue date: 2016-06-23 / The characteristics of the Sensors Wireless Networks (WSNs) make this technology a solution for a variety of purposes, including when it comes to Internet of Things (IoT). Formed by sensor nodes, this type of network is responsible for monitoring and acting on various aspects of the environment to measure temperature or trigger an exhaust fan. However, wireless communication is vulnerable environment changes in which it operates, which could compromise the effectiveness of communication. Thus, this work presents a proposal for a methodology to determine optimal routes based on an estimate of the PER by the RSSI and a protocol for the collection of network RSSIs. The estimated PER was developed by experimental tests with FSK modulation. The collection protocol was implemented in a real network and RSSIs used to determine the best routes. The methodology for allocation of routes was developed with the classification premise of us according to the criticality of your application into two groups, high and low criticality. / As caracter?sticas das Redes de Sensores Sem Fio (RSSF) fazem desta tecnologia uma solu??o para diversas finalidades, inclusive quando se trata de Internet das Coisas (IoT). Formada por n?s sensores, este tipo de rede ? respons?vel por monitorar e atuar em diferentes aspectos do ambiente, como medir a temperatura ou acionar um exaustor. Entretanto, a comunica??o sem fio ? vulner?vel as mudan?as do ambiente em que est? inserida, podendo comprometer a efic?cia da comunica??o. Neste sentido, este trabalho apresenta uma proposta uma de metodologia para determina??o de melhores rotas baseada em uma estimativa da PER pela RSSI e um protocolo para a coleta das RSSIs da rede. A estimativa da PER foi desenvolvida por meio de testes experimentais com a modula??o FSK. O protocolo de coleta foi implementado em uma rede real e as RSSIs utilizadas na determina??o de melhores rotas. A metodologia para atribui??o de rotas foi desenvolvida baseada na classifica??o dos n?s em fun??o de sua criticidade.
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Lokalisering av skidor i lössnö : Självständigt arbete i Teknisk Fysik / Positioning of skis in powder snow : Independent Project in Engineering PhysicsTrella, Fredrik January 2011 (has links)
This report studies the possibility of using some sort of radio sender and transmitter in order to position skis lost in powder snow. It is concluded that a RF-solution on the 433 MHz frequency should be the most efficient. Different forms of directional antennas are examined and studies show that in theory the best suited is the so called “Yagi-Uda antenna”. A solution based on using a Receive Signal Strength Indicator value together with the above mentioned directional antenna is developed. To control these different components microprocessors from Atmel is used. These are programmed in C and compiled with Atmel’s own compiler AVR Studio. Despite all efforts it is proven that the prototype does not perform in an adequate way. An alternative solution based on “byte-loss-rate” is then developed and the results are slightly improved. Nevertheless, the directional properties of the antenna are still too poor why other alternatives are discussed. No fully functioning prototype is achieved but good grounds for further development of the prototype into something that fulfills the specifications are produced.
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Système antennaire directif et reconfigurable pour réseaux de capteurs sans fil / Directive and reconfigurable antenna system for wireless sensor networksDihissou, Akimu Ayan Niyi 06 April 2018 (has links)
Les études montrent généralement que la partie radio est l'une des plus grandes sources de consommation d'énergie dans un nœud de capteur. Cette source de consommation est directement liée au type d’antenne utilisé sur le module radio du nœud. Or, nombre de nœuds de capteurs sans fil sont généralement équipés d'antennes omnidirectionnelles provoquant ainsi un gaspillage de l'énergie dû à leur rayonnement. Face à un tel constat, ce mémoire présente des systèmes d'antennes directives et reconfigurables dédiés à ces nœuds capteurs en lieu et place des antennes omnidirectionnelles pour pallier à cette perte d’énergie. Il s’agit de petites antennes qui doivent respecter pleinement la gamme de fréquences nécessaire pour fonctionner correctement, mais aussi, dont le rayonnement peut être modifié en utilisant des composants actifs peu gourmands en énergie avec un contrôle actif qui doit également être simple. La première solution proposée est une solution antennaire directive inspirée d'une antenne imprimée Yagi/Uda dans la bande ISM-2,4 GHz. Elle offre, en simulation, un gain élevé avec une valeur de 7,3dB et un angle d’ouverture à -3dB de 57 ° dans le plan azimutal. La deuxième solution proposée est une antenne à plusieurs faisceaux (six) possibles dans le plan azimutal. Celle-ci se compose de six monopôles identiques, ayant chacun un port d’alimentation. De par la sélection du port alimenté, un diagramme directif de gain simulé de 4,6 dB et d’angle d’ouverture à -3dB de 55° est obtenu, permettant ainsi une couverture globale du plan azimutal. De plus, une carte électronique dotée d’un switch de type SP6T dédiée à cette antenne a été conçue pour contrôler ces six diagrammes de rayonnement de manière automatique. Afin de réduire le nombre d'éléments rayonnants tout en améliorant les performances radio électriques obtenues, une troisième solution a été proposée. Elle se compose d'un monopôle alimenté et d'un monopôle parasite chargé par une inductance de 9,6 nH. La nature et la valeur de la charge ont été obtenues en utilisant les équations d'Uzkov qui permettent de calculer les coefficients de pondérations dans le cas de deux antennes monopôles alimentées séparément afin de maximiser le gain et la directivité dans une direction privilégiée. Contrairement à l’usage de la carte électronique pour le contrôle de diagramme de rayonnement dans le cas de la structure antennaire à six monopôles, l’aspect reconfigurable en diagramme est obtenu dans ce cas en utilisant des éléments réflecteurs et directeurs activés par des diodes PIN. Elle procure en simulation un gain maximal de 5,2 dB en azimut pour un angle d’ouverture à -3dB de 52°, dans les directions 90° et 270° selon les diodes sélectionnées. Enfin, une application directe de cette structure est proposée pour couvrir plus de deux directions en azimut. Elle consiste en un ensemble de quatre monopôles dans lequel deux d’entre eux sont alimentés et les deux autres sont chargés par des inductances identiques. Il est capable de diriger son rayonnement dans le plan azimutal couvrant des directions sur 360 ° (0 °, 90 °, 180 ° et 270 °). Le gain total réalisé simulé est de 4 dB pour chaque diagramme de rayonnement dans le plan azimutal avec un angle d’ouverture à 3dB d’environ 60°. Des campagnes de mesures ont été effectuées pour chacune des antennes présentées dans ce mémoire. L’indicateur de la puissance du signal reçu (RSSI) a été la grandeur métrique utilisée pour quantifier les performances des antennes proposées. Suite à ces campagnes, nous avons pu remarquer que l’utilisation d’antennes directives seules, améliorant la portée de communication entre deux nœuds de capteurs s’avère insuffisante dans le cas d’un déploiement aléatoire de nœuds capteurs. / Studies have shown that the communication subsystem is one of the greatest sources of energy consumption in wireless sensor networks. This subsystem is directly bounded to the type of antenna used on the radio module. Several sensor nodes are equipped with omnidirectional antennas leading to a waste of energy due to the shape of their beam. Instead of using omnidirectional antennas, directive and reconfigurable antennas system dedicated to wireless sensor networks are presented in this work so as to alleviate the waste of energy. On one hand, such dedicated antennae should be small in size and particularly designed by taking into consideration the frequency bandwidth of the node. On the other hand, their radiation pattern should also be reconfigurable by using powerless active components with a simple active control. To reach these objectives, we have in a first time proposed a directive solution inspired of a Printed-Yagi antenna in the ISM band (2.4-2.485) GHz. It provides high gain with a value of 7.3dB and a half power beam width BW−3dB of 57° in the azimuth plane. Secondly, we have proposed a multiple directional antenna in the ISM band. This antenna consists of six identical monopole antennas arranged in the same structure, having each one feeding port. Due to the selection of each feeding port, the proposed antenna covers the whole azimuthal plane with a simulated beam of 4.6 dB along with a half power beam width BW−3dB of 55°. Moreover, an electronic card equipped with an SP6T switch dedicated to that antenna has been developed to control the radiation pattern of the six identical antennas automatically. Willing to reduce the number of radiating elements while enhancing the radio performance, a third antenna has been proposed. It consists of a fed monopole and a loaded parasitic one having an inductance component of 9.6nH. The nature and the value of this inductance are obtained using the Uzkov equations that calculate the current weighting coefficients in the case of two separately fed antennas to maximize the gain and the directivity in the desired direction. Contrary to the use of electronic card in the control of radiation pattern prior to the conception of the third antenna, the reconfigurable aspect is obtained by using reflectors and director’s elements activated by PIN diodes. It offers a maximum gain of 5.2 dB in simulation at 2.4GHz along with a half power beam width BW−3dB of 52°, in both the 270° and +90° azimuthal directions depending on the selection of the set of PIN diodes. Finally, a straight application of this structure has been proposed in order to cover more than two directions in the azimuth plane. It is an array of four monopole antennas in which two of them are fed and the two others are loaded. Such antenna is capable to steer its radiation pattern in the azimuth plane covering 360° directions (0°, 90°, 180° and 270°). The achieved simulated realized total gain is 4 dB for each radiation pattern in the azimuth plane along with a half power beam width of about 60°. Measurement campaign test has been carried out for each proposed antenna in this work. During these measurements, the received signal strength indicator (RSSI) has been the paramount value to estimate the antenna performance in connection with the sensor node. Following this measurement campaign, we have been able to notice that the use of only directive antennas is not sufficient in a random deployment of sensor nodes. Hence, the reconfigurable aspect of the beam pattern by use of powerless active components should be taken into consideration. Such kind of antennas provide an improvement of the RSSI, which is a key factor in the reduction of collisions drastically on one hand, and on the other hand related to a reduction of power consumption
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Inomhuspositioneringssystem : Personlig navigation inomhus via mobiltelefon / Indoor Positioning System : Personal indoor navigation via mobile phoneJohansson, Charlie, Frid, Martin January 2015 (has links)
GPS används idag för personlig navigering men dessvärre är GPS beroende av fri sikt och presterar sämre i en inomhusmiljö. Ett IPS, inomhuspositioneringssystem, skulle komplet-tera GPS:ens funktion samt öppna dörrar för nya användningsområden inom positionering. I detta examensarbete studerades metoder och tekniker för att möjliggöra ett IPS för en mo-bil enhet. Där teknikerna och metoderna verifieras för att kunna implementeras i en mobil-telefon.En prototyp för ett IPS framställdes för att utreda möjligheterna att navigera i en inomhus-miljö. En radiofingeravtrycksmetod baserat på RSSI-mätningar från Bluetooth-enheter im-plementerades och integrerades med en dödräkningsmetod som använder en IMU för att positionera användaren. Utefter tester och simuleringar utförts presenteras resultatet i form av figurer och tabeller. Med hjälp av prototypen går det att navigera med ett medelfel på 0,26m. Resultatet visar också på att en integrering av två metoder är att föredra då de kan komplettera varandras svagheter. / The GPS is used today for personal navigation, however GPS performs less well in an in-door environment due to the dependency of line of sight. The IPS, Indoor Positioning Sys-tem, will complement the function of the GPS and open doors for new applications. In this thesis studies of methods and techniques are made to enable IPS for a portable device. These techniques and methods are verified that they could be implemented in a smartphone.A prototype was designed to examine the possibility to navigate in an indoor environment. The prototype was built on a RSSI-based radio fingerprinting method over Bluetooth. This method was integrated with a dead reckoning system using an IMU to follow the motions of the user. Tests and simulations are performed along with the results presented in tables and figures. The result shows that it is possible to navigate using the prototype with a mean error of 0.26m. Results are also showing that two methods are to prefer, as they will com-plement each other’s weaknesses.
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The precision of RSSI-fingerprinting based on connected Wi-Fi devicesÖhrström, Tobias, Olsson, Christoffer January 2017 (has links)
Received Signal Strength Indication (RSSI) fingerprinting is a popular technique in the fieldof indoor positioning. Many studies on the subject exist acknowledging Wi-Fi signal variationconnected to Wi-Fi signals, but does not discuss possible signal variation created byconnected devices nor consequential precision loss.Understanding more about the origins of signal variation in received signal strength indication(RSSI) fingerprinting would help deal with or prevent them as well as provide moreknowledge for applications based on such signals. Environments with a varying number ofconnected devices would benefit from knowing changes in localization precision resultingfrom the devices connecting and disconnecting from the access point because it wouldindicate whether workarounds for such circumstances would be necessary.To address this issue, the work presented here focuses on how the precision of RSSIfingerprinting vary given different levels of connected Wi-Fi devices. It was carried out byconducting real world experiments at times of low- and normal levels of connected devices toaccess points on two separate locations and evaluating precision changes between statedactivity levels. These experiments took place at the University of Borås as well as at Ericssonin Borås.Experimental findings indicate that the accuracy does deteriorate in higher levels of activitythan in low activity, even though not enough evidence to determine the precision ofdeterioration. The experiments thereby provide a foundation for location-based applicationsand services that can communicate the level of positional error that exist in differentenvironments which would make the users aware but also make the applications adaptaccordingly to different environments. Based on the precision achieved, we identify variousapplications that would benefit from our proposed model. These were applications that wouldtrack mobile resources, find immobile resources, find the movement flows of users as well asnavigation- and Wi-Fi coverage applications.Further research for investigating the exact correlation between access point stress andprecision loss is proposed to fully understand the implications connected devices have onRSSI fingerprinting.
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Webové rozhraní pro sledování provozu v bezdrátových sítích / Web Interface for Wireless Network MonitoringGábor, Martin Unknown Date (has links)
The aim of this diploma thesis is to analyze, design and create the architecture of the WSageNt system web interface. The main focus of the system will be traffic monitoring and topology control of the network. The work describes basic technologies, design principles and implementation methods.
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Bluetooth IPS med en mottagare och Kalmanfiltrering / Bluetooth IPS with one reciever and Kalman filteringJohansson, Alfred January 2019 (has links)
This study aims at investigating a central mounted Indoor Positioning System based onBluetooth RSSI values and Kalman filtering where the Bluetooth module is mounted on arotating arm around an axle. The purpose is to investigate how the length of the arm and therotational speed influence on the possible positioning accuracy of the artefact. As requested bythe company Combitech AB, the artefact will also be evaluated whether the design is areasonable alternative to de most common Bluetooth based Indoor Positioning Systems. Thecase study is performed using design science as an artefact is developed and evaluated. Theartefact is tested in a predetermined test environment, in this case an office room. In the testenvironment, measurements will be realized on the different iterations of the artefact. Theresult of the study is the achieved positioning accuracy for the artefact in two and threedimensions. Linear equations describing the relationship between the length of the arm andthe achieved accuracy of the artefact will also be proposed. The best accuracy achieved in twodimensions was 510 centimeters. The best achieved accuracy in three dimensions was 730 centimeters. The observed relationship between the length of the arm and the uncertainty ofthe trilaterated position is that when the length of the arm increases the uncertainty decreasesin both two and three dimensions.
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Evaluation of Software Defined Radio platform with respect to implementation of 802.15.4 ZigbeeDabcevic, Kresimir January 2011 (has links)
With the development of powerful computational resources such as Digital Signal Processors and Field Programmable Gate Arrays, It has become possible to utilize many radio functions via software. This is the main concept of an up-and-coming technology of Software Defined Radio. In the Thesis, a number of platforms for implementation of Software Defined Radio has been evaluated. Platform that proved to be most suitable for the project was Ettus’ USRP N210. Using the platform, implementation of 802.15.4 Zigbee’s physical layer was done, where experiments whose outputs can later be used to compare performance with respect to "hardware radios" were performed. / Med utvecklingen av enheter med kraftfulla beräkningsegenskaper som “Digital Signal Processors” och “Field Programmable Gate Arrays” har det blivit möjligt att implementera flera radiofunktioner i mjukvara. Det är huvudkonceptet i den uppåtgående teknologin mjukvaru definierad radio.I det här examensarbetet har ett flertal plattformar för mjukvaru definierad radioutvärderats. Plattformen som visade sig vara mest lämplig för projektet var Ettus USRP N210. En implementation av IEEE 802.15.4 Zigbees fysiska lager har realiserats till plattformen. Experiment, vars utdata senare kan användas för att jämföra prestanda mellan mjukvaru definierad radio och hårdvaru baserad radio, har även utförts. / TESLA - Time-critical and Safe wireLess Automation communication / GAUSS - Guaranteed Automation communication Under Severe disturbanceS
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Enhanced Hole Punching For Rssi Location Tracking In HospitalsPecel, Deniz 01 March 2008 (has links) (PDF)
With the enhancement of the Radio signal communication systems, Wi-Fi technology become a &ldquo / de facto&rdquo / standard used in Campus areas such as hospitals and universities. Besides being used as a data communication method, Received Signal Strength Indicator (RSSI) is also used as a location tracking method. There are lots of studies enhancing the RSSI based location tracking.
In this thesis we tried to generate a test environment as close to a real Wi-Fi network scenario as possible. Our aim is to implement a simple moving client among different wireless local area networks, which is tracked across the internet by a
stationary client. We also assumed that there is a Network Address Translation (NAT) at both LAN internet edges.
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