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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.
251

How to Solve the Problem of Inactivity Amongst Preschool Children with IoT / Hur man löser problemet med inaktivitet bland dagisbarn med hjälp av IoT

Leander, Malin January 2024 (has links)
WHO has set up activity guidelines for children between 0-5 years of age. If children fail to follow the guidelines they risk developing NCD diseases in the future as a consequence. Several children in the age group fail to follow these guidelines all over the world. Adults have used IoT solutions to track and maintain their activity. There have been IoT devices developed for kids but none focus on the age group of 0-5 year old’s. Therefore the objective for this study was to examine how the age group could reach the guidelines for physical activity with the assistance of an IoT device. To study this the goal was to design an application that will assist parents in tracking their children’s activity and giving them suitable exercises. To investigate the subject a theoretical framework was created. It focused on investigating how physicalactivity can be measured, what sensors could be used, how could the data be visualized effectively, what motivates children to move and what research method and data collection methods that could be used throughout the project. The method chosen was the double diamond method which consisted of the stages discover, define, develop and deliver. During the discover phase an interview was performed with a key-informant with expertise in sports medicine and activity tracking with 3-5 yearold’s. A survey was also sent out to parents to investigate the population. In the define phase a concept was formed from the collected data. In the develop stage a Lo-fi Figma prototype was created and tested on both the key-informant and expertswithin UX and/or IT-consulting. The Lo-fi prototype contained graphs showcasing the family’s activity, activities to perform with their child, a reward page were children could gain rewards for activity and much more. The results showed that the rewards system introduced confused the participants and some thought it would berisky to introduce rewards for activity to children. This since they might then only be active for the reward, not for the fun of the activity itself. In the deliver phasea Mid-fi prototype was created from the feedback received through Lo-fi usabilitytesting. The Mid-fi removed the rewards and added a calendar page. At the calendar page the family could plan and wish for activities. The Mid-fi was tested on parents and the results showed that several of them had a hard time finding the wish-list functionality. There were also many participants who wanted to interact with thegraphs to read more specific information. The discussion evaluated the Mid-fi inrelation to the test results and the theoretical framework. Through the analysis it was concluded that improvements can be made for future versions of the prototype. The conclusions evaluated the Mid-fi in relation to the objective and found that the prototype needed further testing with children to conclude if it would be able to help them follow the WHO’s guidelines. It was also concluded that the application would help parents track their child’s movements as many parents would want to use the application and they all understood the used data visualizations. It was lastly concluded that further research with child care practitioners would have to be performed to identify suitable exercises for the children. However, as the app provides a template to sort and recommend activities, it will help parents choose suitable activities for their child when the library has been built up. / WHO har upprättat riktlinjer för fysisk aktivitet för barn mellan 0-5 år. Om barn inte följer riktlinjerna riskerar de att utveckla icke-smittsamma sjukdomar (NCD) i framtiden som en konsekvens. Flera barn i denna åldersgrupp misslyckas medatt följa dessa riktlinjer över hela världen. Vuxna har använt IoT-lösningar för attspåra och upprätthålla sin egen aktivitet. Det har utvecklats IoT-enheter för barn, men ingen av dem fokuserar på åldersgruppen 0-5 år. Därför var syftet med denna studie att undersöka hur åldersgruppen kan följa riktlinjerna för fysisk aktivitet med hjälp av en IoT-enhet. För att studera detta var målet att designa en applikation som hjälper föräldrar att spåra sina barns aktivitet och ge dem lämpliga aktiviteter. För att undersöka ämnet skapades ett teoretisk ramverk. Det fokuserade på att undersöka hur fysisk aktivitet kan mätas, vilka sensorer som kan användas, hur data kan visualiseras effektivt, vad som motiverar barn att röra sig och vilka forsknings- och datainsamlingsmetoder som kan användas under projektet. Den valda metoden var Double Diamond, som bestod av faserna upptäcka, definiera, utveckla och leverera. Under upptäcktsfasen genomfördes en intervju med en nyckelinformant med expertis inom idrottsmedicin och aktivitetsspårning för barn mellan 3-5 år. En enkät skickades också ut till föräldrar för att undersöka populationen. I definieringsfasen formades ett koncept utifrån de insamlade datat. I utvecklings-fasen skapades och testades en Lo-fi Figma prototyp på både nyckelinformantenoch experter inom UX och/eller IT-konsulting. Lo-fi prototypen innehöll grafer som visade familjens aktivitet, aktiviteter att utföra med deras barn, en belöningssida där barn kunde få belöningar för aktivitet och mycket mer. Resultaten visade att belöningssystemet förvirrade deltagarna och vissa ansåg att det skulle vara riskabelt att införa belöningar för aktivitet till barn. Detta eftersom de då kanske bara skulle vara aktiva för belöningen och inte för aktivitetens egen skull. I leveransfasenskapades en Mid-fi prototyp utifrån den feedback som erhölls genom användbarhet-stester av Lo-fi prototypen. Mid-fi prototypen tog bort belöningarna och lade till en kalendersida. På kalendersidan kunde familjen planera och önska aktiviteter. Mid-fi prototypen testades på föräldrar och resultaten visade att flera av dem hade svårt att hitta önskelistefunktionen. Det var också många deltagare som ville interagera med graferna för att läsa mer specifik information. Diskussionen utvärderade Mid-fi pro-totypen i relation till testresultaten och det teoretiska ramverket. Genom analysen konstaterades det att förbättringar kan göras för framtida versioner av prototypen. Slutsatserna utvärderade Mid-fi prototypen i relation till målet med studien och fann att prototypen behövde ytterligare testning med barn för att fastställa om den skulle kunna hjälpa dem att följa WHO:s riktlinjer. Det konstaterades också att applikationen skulle hjälpa föräldrar att spåra sina barns rörelser då många föräldrar ville använda applikationen och alla förstod de använda datavisualiseringarna. Slutligen konstaterades det att ytterligare forskning med barnomsorgspersonal måste genomföras för att identifiera lämpliga övningar för barnen. Men eftersom appen tillhandahåller en mall för att sortera och rekommendera aktiviteter, kommer den att hjälpa föräldrar att välja lämpliga aktiviteter för sina barn när bibloteket byggts upp.
252

Passive antenna systems printable on conformable supports / Système passif antennaire imprimable sur support conformable

Nguyen, Hong Duc 23 May 2018 (has links)
Au cours des dernières années, en raison de la demande croissante de produits de plus enplus légers, plus petits et moins chers à l'intérieur des appareils portables, l'électronique flexible émerge sur le marché commercial comme une nouvelle génération d'électroniques. Les substrats rigides conventionnels sont remplacés par des matériaux plus minces, flexibles et à faible coût tels que papier, polymère, plastique pour la fabrication des composants et circuits. En même temps, les futurs boîtiers électroniques demandent de plus en plus de nombreux systèmes sans fil afin d'offrir de multiples services et applications (ZigBee/Z-Wave, WLAN, DECT, Bluetooth, RF4CE, 3G/4G, etc.). À cause de l'intégration d'un très grand nombre d'antennes pour satisfaire l'opération de toutes ces applications, les connectivités deviennent donc un grand défi pour les exigences de coût. C'est pourquoi on voudrait remplacer l'ensemble du système d'alimentation/d'interconnexion à la carte mère PCB par une technologie homogène, collective. Ce travail de thèse vise à développer une nouvelle technologie "verte" et faible coût dédiée à la conception et réalisation de systèmes antennaires et d'interconnexions sur les matériaux flexibles (tels que papier) à base d'encres conductrices et de procédés de fabrication additifs comme impression. Le défi scientifique est de concevoir des systèmes antennaires répartis spatialement sur les faces internes en plastique du boîtier électronique sous forme des stickers RF 3D et connectés directement à la carte PCB par une solution innovante, à faible coût pour des applications multimédia sans fil dans la gamme de fréquences de 1.8-6 GHz. / In recent years, due to the growing demand for lighter, smaller and cheaper electronic products Inside portable devices, clothing and packaging materials, flexible electronics is emerging on the commercial market as a new generation of electronics. Conventional rigid substrates will be replaced by thin, flexible, low-cost materials such as paper, polymer, and plastic for the manufacturing of components and circuits. Concurrently with the powerful development of flexible electronics, the future electronic devices have drastically demanded more wireless systems in order to offer multiple services and applications (ZigBee/Z-Wave, WLAN, DECT, Bluetooth, RF4CE, 3G/4G, etc.). Because of the integration of a great number of antennas to satisfy the operation of all these applications, the connectivities thus become a big challenge for cost constraints. This is the reason why we would like to replace the entire interconnection system with the PCB mainboard by a homogeneous, collective technology.This thesis work aims at developing "green", low-cost and innovative technology devoted to the design and realization of antenna systems and interconnections on flexible materials (such as paper) based on conductive inks and additive manufacturing processes like printing. The scientific challenge lies on the design of spatially distributed antenna systems on the internal plastic sidewall of the electronics box in the form of 3D RF stickers and directly connected to the PCB mainboard by an innovative, low-cost solution for wireless multimedia applications in the frequency range of 1.8-6 GHz.
253

Utopia Trek : utopibegreppets resa genom Star Trek / Utopia Trek : a travel through Star Trek with the concept of utopia

Schön, Anna January 2004 (has links)
<p>Humanity has always dreamed about a better world. These dreams has manifested themselves in the vision of Utopia - the good place, but also the non-existing place. Up until World War II man still wrote optimistic descriptions of this ideal world, and spread the idea through literature. In the aftermath of the atomic bomb and under the influence of the cold war, these publications seized to surface in literary surroundings. Despite this utopia did not die - it has only changed. Today you can find utopia, not primarily in books, but in Science Fiction. TV’s biggest Science Fiction-series, Star Trek, is perhaps the best example of this. The Master's thesis "Utopia Trek - a travel through Star Trek with the concept of utopia" takes you through the history of utopia and into its new habitat, Star Trek, where the essence of a utopia for the 21th century is found, discussed and reevaluated.</p> / <p>Mänskligheten har alltid drömt om en bättre värld. Dessa drömmar har manifesterats i visionen om Utopia - den goda platsen, men också platsen som inte existerar. Fram till andra världskriget skrev man fortfarande optimistiska beskrivningar av denna idealvärld, och spred idén via litteraturen. Efter hotet från atombomben och under påverkan av det kalla kriget, slutade dessa publikationer att dyka uppi litterära sammanhang. Trots detta dog inte drömmen utopia - det har bara förändrats. Idag kan man finna utopia, inte företrädesvis i böcker, utan i science fiction. Tv:s största science fiction-serie, Star Trek, är kanske det bästa exemplet på detta. Magisteruppsatsen "Utopia Trek - utopibegreppets resa genom Star Trek" tar dig genom utopias historia och in i dess nya hemvist, Star Trek, där essensen av ett utopia för 2000-talet upptäcks, diskuteras och omvärderas. </p>
254

應用Wi-Fi與GPS技術於室外定位之研究 / Study on Outdoor Positioning With Wi-Fi/GPS

郭清智 Unknown Date (has links)
由於可攜式行動裝置近年來快速成長,隨著行動裝置與地理資訊的結合發展出的適地性服務 (Location-Based Service, LBS),也呈現越來越多的應用方式。LBS最基本的功能為定位,定位精度好壞也影響著LBS的應用面,越高的定位精度應用面越廣。常見的定位方式便是用GPS導航定位,但是在都會地區越是繁榮的地方往往過多的建物使衛星訊號被阻擋,導致GPS的定位會受到影響,造成平面誤差量會在15公尺以上,或是無法定位。利用都市區域有Wi-Fi訊號分布的特性,藉由區分不同的Wi-Fi訊號來源與接收強度,做出定位判斷,可以使原本GPS無法定位的區域,也可以利用Wi-Fi訊號來做定位。本研究嘗試使用高感度GPS接收器,在建物周邊定位,及在GPS無法運作時使用Wi-Fi訊號來做定位依據,提高整體的定位成功率,並嘗試利用Wi-Fi定位與GPS協同運作來提高整體精度。Wi-Fi定位採用訊號紋辨識法,欲使用訊號紋辨識法必先建立Wi-Fi訊號資料庫,包含地理坐標與對應的訊號來源與強度分布。實驗區為政治大學山下校區綜合院館四周面積約1.76公頃區域,模擬被遮蔽狀況下的GPS導航定位精度,配合Wi-Fi定位來輔助GPS定位結果。結果顯示利用兩種定位系統,可使平面平均定位誤差小於10公尺,高程平均定位誤差小於1.5公尺。 / The positioning accuracy is an important issue for Location-Based Service (LBS). LBS has many products, and its applications are usually based on Global Positioning System (GPS), because GPS navigation has been very mature. GPS has a typical outdoor positioning error of up to 15 meters for civilian users. Hence it has become a viable method for civilian to carry out coarse positioning. However, it has its shortcomings. GPS is available only in outdoors with a clear view of the sky. Since Wi-Fi (Wireless Fidelity) has become another positioning technology which is capable of performing positioning in indoor environments and urban canyons. Wi-Fi positioning is using fingerprinting in this study. This study is desirable to integrate GPS and Wi-Fi positioning technologies for ubiquitous positioning. The related issues of Wi-Fi/GPS technologies, such as database quality, analysis of algorithms, and database processing procedures were studied. Test data sets from National Chengchi University (NCCU) campus will be used to test the proposed algorithms. By using those two positioning system , it is revealed that the positioning accuracy made at the test sites resulted that the 2D coordinate average error is less than 10 meters, elevation positioning average error is less than 1.5 meters.
255

Internet of Things &amp; Kommunikationsprotokoll / Internet of Things &amp; Communication Protocol

Sabel, Ida January 2015 (has links)
Genom att studera olika kommunikationsprotokoll kunna svara på vad det är som gör att ett visst protokoll är bäst anpassat för att användas mellan mobila enheter och IoT-enheter. I arbetet användes en kvalitativ litteraturstudie för att ge en grundlig teoretisk bakgrund samt en experimentell studie där ett par teorier undersökts ifall de stämmer med resultaten ifrån verkligheten. De fem faktorerna kompatibilitet, batteritid, frekvens, räckvidd och tillförlitlighet undersöktes hos kommunikationsprotokollen Bluetooth Low Energy (BLE), Närfältskommunikation (NFC) och Wi-Fi. Dessa tre valdes eftersom de stöds av nyare mobila plattformar idag. Kommunikations-protokollen analyserades sedan gentemot olika användningsområden inom IoT, eftersom påståendet vad som är bäst anpassat beror på vad situationen kräver för egenskaper. En systemutvecklare som ska välja kommunikationsprotokoll till en IoT-tillämpning och läser denna rapport bör själv jämföra de olika protokollen mot varandra inom de fem faktorerna för att kunna avgöra vilket protokoll som passar bäst inom dennes situation. I arbetet utfördes endast experimentella studier på BLE på grund av begränsningar inom utrustningen. Ytterligare experiment inom NFC och Wi-Fi skulle ge ett bredare perspektiv med fler infallsvinklar. / By studying different communication protocols respond to what it is that makes a certain protocol best suited for use between mobile devices and IoT devices. This study used a qualitative literature study to create a proper theoretical background and an experimental study where two theories were investigated in whether they matched wih the results from the reality. The five factors compatibility, battery loss, frequency, range and reliability were investigated in the communication protocols Bluetooth Low Energy (BLE), Near field communication (NFC) and Wi-Fi, these three because they are supported by newer mobile platforms today. The communication protocols were then analysed against various uses in the IoT, since the claim what it is that makes it best suited depends on what the situation requires. A system developer that is about to select the communication protocol to use in an IoT application and reads this study should compare the different protocols to each other within the five factors to determine which protocol is best suited for his situation. This study only performed experimental studies on BLE because of limitations in the equipment. Additional experiments on NFC and Wi-Fi would provide a wider perspective.
256

Matemática discreta: aplicações do Princípio de Inclusão e Exclusão

Bezerra Neto, Sebastião Alves 17 August 2016 (has links)
Submitted by ANA KARLA PEREIRA RODRIGUES (anakarla_@hotmail.com) on 2017-09-05T16:47:02Z No. of bitstreams: 1 arquivototal.pdf: 1153647 bytes, checksum: a384e4d5e2acf05cec52ece972237c23 (MD5) / Approved for entry into archive by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2017-09-06T10:49:22Z (GMT) No. of bitstreams: 1 arquivototal.pdf: 1153647 bytes, checksum: a384e4d5e2acf05cec52ece972237c23 (MD5) / Made available in DSpace on 2017-09-06T10:49:22Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1153647 bytes, checksum: a384e4d5e2acf05cec52ece972237c23 (MD5) Previous issue date: 2016-08-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The process of teaching and learning of mathematics is closely related to the resolution of theoretical and practical problems, which often involve situations of everyday life in our society. This work aims to present the Inclusion and Exclusion Principle as a tool for solving many problems involving counting elements, especially those that appear double, triple counting, among others. It also seeks to relate it with the determination of prime numbers of a number and the Sieve of Eratosthenes, use it to systematize the Formula of the function Fi ( Phi) Euler, as well as for determining the number of permutations Chaotic and number of Sobrejetoras functions. / O processo de ensino aprendizagem da Matemática está intimamente relacionado com a resolução de problemas teóricos e práticos, os quais geralmente envolvem situações do cotidiano de nossa sociedade. Esse trabalho tem como objetivo apresentar o Princípio da Inclusão e Exclusão como ferramenta para resolução de vá- rios modelos de problemas que envolvem a contagem de elementos, principalmente aquelas que aparecem contagem duplas, triplas, dentre outras. Além disso, busca relacioná-lo com a determinação de números primos de um número e com o Crivo de Eratóstenes, utilizá-lo para sistematizar a Fórmula da Função Fi ( ) de Euler, bem como para a determinação do Número de Permutações Caóticas e do Número de Funções Sobrejetoras.
257

Utopia Trek : utopibegreppets resa genom Star Trek / Utopia Trek : a travel through Star Trek with the concept of utopia

Schön, Anna January 2004 (has links)
Humanity has always dreamed about a better world. These dreams has manifested themselves in the vision of Utopia - the good place, but also the non-existing place. Up until World War II man still wrote optimistic descriptions of this ideal world, and spread the idea through literature. In the aftermath of the atomic bomb and under the influence of the cold war, these publications seized to surface in literary surroundings. Despite this utopia did not die - it has only changed. Today you can find utopia, not primarily in books, but in Science Fiction. TV’s biggest Science Fiction-series, Star Trek, is perhaps the best example of this. The Master's thesis "Utopia Trek - a travel through Star Trek with the concept of utopia" takes you through the history of utopia and into its new habitat, Star Trek, where the essence of a utopia for the 21th century is found, discussed and reevaluated. / Mänskligheten har alltid drömt om en bättre värld. Dessa drömmar har manifesterats i visionen om Utopia - den goda platsen, men också platsen som inte existerar. Fram till andra världskriget skrev man fortfarande optimistiska beskrivningar av denna idealvärld, och spred idén via litteraturen. Efter hotet från atombomben och under påverkan av det kalla kriget, slutade dessa publikationer att dyka uppi litterära sammanhang. Trots detta dog inte drömmen utopia - det har bara förändrats. Idag kan man finna utopia, inte företrädesvis i böcker, utan i science fiction. Tv:s största science fiction-serie, Star Trek, är kanske det bästa exemplet på detta. Magisteruppsatsen "Utopia Trek - utopibegreppets resa genom Star Trek" tar dig genom utopias historia och in i dess nya hemvist, Star Trek, där essensen av ett utopia för 2000-talet upptäcks, diskuteras och omvärderas.
258

Etude par simulation et mesure d'un système d'exposition d'animaux aux ondes radioélectriques induites par les systèmes wi-fi / Study by simulation and measure of a system of exhibition of animals in the radio waves led by the Wi-Fi systems

Wu, Tongning 20 February 2009 (has links)
Ce travail de thèse consiste en la conception et l'analyse d’un système d'exposition des animaux in vivo avec les signaux Wi-Fi dans une chambre réverbérante. La nouvelle méthode d'excitation est appliquée avec 6 antennes qui fonctionnent aléatoirement pour avoir un champ plus homogène et des ondes venant de toutes les directions. Cette configuration permet d'éviter une grande taille du brasseur de la chambre réalisée. La répartition de puissance chez les rats est étudiée par la méthode hybride de simulation-mesure. La puissance incidente est enregistrée de même que le champ au centre de la chambre. Le rapport de la puissance incidente sur E carré moyenné est déterminé. La méthode FDTD est choisie pour la simulation et permet d’analyser la répartition de la puissance absorbée par les rats. La distribution du champ dans la chambre suit une statistique de Rayleigh comme il a été prouvé par les études et les mesures. Donc, la boîte de Huygens est utilisée pour émettre des ondes planes aléatoires (avec les paramètres suivant distribution Rayleigh) et exposer les rats. On peut alors obtenir le rapport de DAS pour le corps entier chez les rats sur E carré moyenné dans la chambre. Donc il est possible de relier le DAS corps entier chez les rats et la puissance d’entrée dans la chambre à E carré moyenné. Une autre méthode de simulation est aussi appliquée pour vérifier ce résultat. L’évaluation de la variabilité des résultats pour plusieurs paramètres à différents âges des rats est effectuée. En générale, les sources de variabilité sont classifiées selon trois parties : simulation, mesure, et interface entre les deux. Le DAS corps entier chez les rats pendant toute la période d’exposition avec le domaine de variabilité sont présentés dans ce travail. Cette étude pourra être utilisée afin d'évaluer des résultats d’une exposition à long terme des animaux. Elle pourra aussi servir à caractériser le champ dans des environnements domestiques et urbains / This thesis dedicates to design and analysis for the animal in vivo Wi-Fi exposure system by reverberation chamber. 6 random functioned antennas are deployed in the reverberation chamber to radiate the rats with homogenous field and Omni-direction waves. So, there is no significant size stirrer in the system. Power absorption by rats is studied by the simulation-measurement hybrid method. In this method, by measurement, incident power and the mean squared E in the system are recorded. The ratio these factors are obtained. For simulation, FDTD is chosen to analyse the power absorption by the rats. E distribution in reverberation chamber is proved as Rayleigh statistics by studies and measurements. One Huygens box is constructed to radiate the rats. There is no need to realise the wall, the antennas and the accessories of the system. So the whole body averaged SAR can be obtained with the mean squared E in the chamber. Then whole body averaged SAR is linked with the incident power. One other method has also been applied to verify the results. Evaluation of the result variability depending on different parameters of rats with different ages is performed. The variability comes from simulation, measurement and interface between these two parts. Whole body averaged SAR with the variability domain on function of the rat's age is presented in this thesis. This work can be used to evaluate the long term animal exposition. It can also serve to characterise the field in modern domestic and urban environments
259

Modélisation et optimisation de la consommation énergétique d'un système de communication Wi-Fi / Modeling and optimization of the energy consumption of a Wi-Fi communication system

Benali, Wissem 17 October 2017 (has links)
La forte augmentation du nombre de terminaux connectés ces dernières années et l'utilisation croissante des technologies de communication impacte de manière non négligeable la facture énergétique. Pour enrayer cette augmentation de la consommation énergétique, il devient primordial de pouvoir comparer en termes de consommation les algorithmes de communications numériques, afin de développer l'architecture de transmission la moins énergivore. Dans cette thèse, la couche physique des standards Wi-Fi IEEE 802.11ac est analysée sous un angle énergétique. La puissance dissipée dans les circuits pour faire fonctionner les algorithmes de traitement de signal est prise en compte en plus de la puissance d'émission d'antenne classique. La méthodologie mise en œuvre inclut à la fois des simulations et des développements sur plateforme matérielle (FPGA), permettant d'obtenir des évaluations de la consommation plus réalistes. Nous avons dans un premier temps analysé de façon isolée les éléments composant les chaines de communications numériques. Puis nous avons intégré les périodes d'activité et d'inactivité de chaque élément dans le calcul de la consommation énergétique globale des chaines. Nous proposons une méthode pratique et efficace d'estimation de la consommation, incluant une base de données issue de simulations, et une analyse théorique des taux d'activité de chaque élément de la chaine. Ces résultats permettent d'analyser la répartition de la consommation en puissance des éléments composant les émetteurs et les récepteurs, et de comparer diverses architectures et jeux de paramètres. En particulier, nous avons évalué l'impact de deux architectures de Transformées de Fourier Rapides sur la consommation globale du système. / The strong increase of the number of connected devices in recent years and the increasing use of communication technologies has a significant impact on the energy bill. To stop the increase in energy consumption, it is essential to be able to compare the digital communication algorithms in terms of consumption, in order to develop the most energy-efficient transmission architecture.In this thesis, the IEEE 802.11ac Wi-Fi standard of physical layer is analyzed at an energy point of view. The power dissipated in the circuits for operating the signal processing algorithms is taken into account in addition to the antenna transmission power. The implemented methodology includes both simulations and developments on a hardware platform (FPGAs), resulting in more realistic consumption assessments.First, we analyzed separately the components of the digital communications chains. Then we integrated the periods of activity and inactivity of each element in the calculation of the global energy consumption of the chains. We propose a practical and efficient method of estimating consumption, including a database derived from simulations, and a theoretical analysis of the activity rates of each element of the chain.These results make it possible to analyze the distribution of the power consumption of the elements composing transmitters and receivers, and to compare various architectures and sets of parameters. In particular, we evaluated the impact of two Fast Fourier Transform architectures on overall system consumption.
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Metodika měření kvality služeb ve Wi-Fi sítích / Methods for Quality of Service measurement in Wi-Fi networks

Bachan, Jiří January 2008 (has links)
This work deals with the wireless Wi-Fi networks, that used unlicenced ISM frequency band 2,4 GHz. These wireless networks are very extended in these days and used mainly for the Internet connection. With the multimedia data transfers expanding it’s necessary to ensure the specific quality of service QoS in wireless networks mainly for applications, which are sensitive to delay or packets lost. The main aim of this work is to describe Wi-Fi networks based on IEEE 802.11b/g/n standards, description of QoS techniques according to IEEE 802.11e standard and description of parameters describing QoS for the VoIP services. The practical part is divided on a two parts. The problems of measuring the radio link quality and the creation of simple program for quality of wireless connection analysis are solved in the first part. The second part incluledes measuring of the lost packets number in Wi-Fi network with the commercial application AirMagnet Laptop Wireless LAN Analyzer and measuring of the signal noise influence with the help of spectrum analyzer and vector signal generator.

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