• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 270
  • 93
  • 61
  • 55
  • 22
  • 11
  • 9
  • 8
  • 6
  • 4
  • 3
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 591
  • 136
  • 132
  • 123
  • 101
  • 92
  • 89
  • 88
  • 83
  • 67
  • 66
  • 58
  • 56
  • 51
  • 49
  • 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.
151

DMX-communication over Bluetooth low energy mesh network

Danielsson, Thomas January 2019 (has links)
With the addition of mesh capability to Bluetooth low energy(BLE) in 2017 new possibilities open up for the Internet of Things applications of Bluetooth. With the rapidly increasing number of connected devices a few new standards are competing for being the standard protocol for low power mesh communication. BLE is mostly aimed towards low bandwidth data such as sensor readings or light control. However, this thesis attempts to investigate the viability of adapting BLE mesh nodes to communicate DMX-data which is a protocol widely used in lightning and stage effects. The system is implemented on Bluetooth development kits and the latency and power consumption are measured. The results show that the latency is significant and with high variance if the full DMX frame is transmitted, rendering the application non-applicable on many real-time applications. It can however be justified in some applications due to Bluetooth's well established eco-system of devices and functionality where the nodes could extend their capabilities by implementing already established BLE models. By only transmitting the updated channels the latency can be lowered to values that would in some applications be indistinguishable from wired connection. The energy consumption of BLE mesh suffers greatly with the addition of mesh due to its constant scanning but by implementing low power nodes which keep the radio off during certain intervals this consumption could be greatly decreased. The results also show a high variance of latency depending on the node configuration regarding to the placements and the number of hops required to reach the intended recipient. / Bluetooth har länge varit standardprotokollet för kommunikation mellan två stycken enheter. 2017 kom tillägget med mesh till Bluetooth. Mesh innebär att andra enheten i närheten ska skicka vidare meddelanden och därigenom tillåta kommunikation mellan enheter som är utanför direkt radiokontakt. DMX är ett protokoll som används inom ljus- och sceneffekter. Bluetooth mesh är utformat för att skicka små datamängder som till exempel sensordata eller styra glödlampor. Denna uppsats kommer utvärdera om det är användbart att skicka DMX-data över Bluetooth mesh. En implementation gjordes på Bluetooth utvecklingskort och resultatet visar på en signifikant fördröjning och med hög varians vid överföring av alla DMX-kanaler, vilket innebär att denna implementation inte är användbar vid många användningsområden. Men trots det kan den vid vissa fall vara användningsbar, mycket till hjälp av Bluetooths billiga och utbyggda ekosystem av produkter och tilläggsfunktioner. Eftersom Bluetooth mesh byggs in i en del befintliga byggnader kan de uppoffringar man får göra vid överföringar av DMX-data vara acceptabel då man kan uttnyttja befintliga nät. Strömförbrukningen ökar avsevärt vid mesh jämfört med klassisk lågenergi Bluetooth då mesh måste skanna radiotrafiken konstant. Vid implementationen av lågenergi noder kan dock radio vara i stand-by och starta endast vid speciella tidpunkter och man kan därigenom få avsevärt lägre strömförbrukning, med uppoffringen att DMX-datan inte kan överföras omgående. Det visade sig också att noduppställningen kraftigt påverkade variansen i överföringshastighet och att detta måste ta i hänsyn vid valet om DMX över Bluetooth mesh är användbart i just det fallet.
152

Estimating the number of people in an area : Using Bluetooth and WiFi signals

Naga, Alex January 2019 (has links)
In this world of the digital era, a large percentage of the world population and almost everyone in Sweden today owns a smartphone, and possibly even a smartwatch. By using this to our advantage, it would be possible to check whether an area is currently very busy or not, based on how many smartphones or other wearables technology it is possible to discover in the area. The approach chosen to dig into this problem was to research suitable hardware devices with Bluetooth and WiFi compatibility, that could detect probe requests broadcasted by smartphones or wearable devices in the area. The knowledge gained from the research in this thesis set the foundation for implementing a prototype with the desired functionality. Testing of the prototype was then conducted in a university library and analysed how it performed. Through testing the developed prototype, it revealed that it is possible to obtain an indication of whether an area is currently very crowded or not using Bluetooth and WiFi signals. A suggestion on how to proceed in creating more fine-tuned improvements is also described.
153

Silenciador regulable con control inalámbrico

Arce Cigüeñas, Diego Martin 09 September 2014 (has links)
Los silenciadores son componentes utilizados para reducir las emisiones sonoras emitidas por los automóviles. Para lograrlo se reduce la efectividad del motor debido al efecto denominado contrapresión. Esto ocurre puesto que para reducir la intensidad de las emisiones sonoras se reduce la velocidad de circulación de los gases de escape provocando que se interrumpa la libre circulación del flujo y se tenga que destinar parte de la potencia del motor en expulsar correctamente gases de combustión. Por esta razón se ha diseñado un sistema que permite modificar los modos de operación del silenciador (denominado en inglés Muffler). Con este sistema mecatrónico se brinda la posibilidad de mantener la reducción de las emisiones sonoras para lugares urbanos respetando las normas legales que permiten un límite máximo de 88 dB para vehículos livianos; pero también se ofrece la posibilidad de modificar el sistema para que la salida de los gases de escape sea libre. Con la expulsión libre del flujo de gases se logra aumentar la eficiencia del motor del automóvil y a la vez disminuir el consumo de gasolina cuando el usuario se encuentre en carreteras o pistas de carreras. También se brindan otros tipos de configuraciones que permiten combinar ambas características buscando un equilibrio entre el sonido y la eficiencia. El sistema es controlado mediante una aplicación instalada en un dispositivo móvil inteligente (Smartphone). Esta aplicación permite realizar la conexión con el silenciador mediante la tecnología inalámbrica Bluetooth. Mediante la aplicación se puede seleccionar uno de los cuatro estados en los que se puede configurar al silenciador. Además se muestra en la pantalla del Smartphone la animación de la configuración interna del sistema, la cual corresponde al estado de funcionamiento que selecciona el usuario. Finalmente el sistema está diseñado para que su instalación sea sencilla, para que sea alimentado desde la batería y para que sea compatible con todo tipo de automóvil. / Tesis
154

Augmented reality for high-throughput phenotyping

Wu, Shanshan January 1900 (has links)
Master of Science / Department of Computer Science / Mitchell L. Neilsen / Smart glasses, like smart phones, have separate operating systems, and can execute many different kinds of software and games. Smart glasses can be used to add a schedule, map navigation, interact with friends, take photos and videos, and make video calls with friends through voice control. They can support wireless network access through a mobile communication network. Bluetooth is a radio technology that supports short-range communication between of the devices. It can exchange information between devices including mobile phones, wireless headsets, laptops, etc. Bluetooth technology can effectively simplify the communication between mobile devices. This thesis focuses on smart glasses applications for high-throughput phenotyping which requires a data monitor, data synchronization, Bluetooth service, and voice control between devices. On the Android side, the application, which is extended, is called Field Book. The new software called Field Book AR, includes a data monitor module and a Bluetooth server module to achieve data exchange with smart glasses. On the smart glasses side, the application is called DataReceiver. It receives voice commands from users and controls the actions of Field Book AR. Also, when Field Book detects data changing, it accepts new data and shows changes to the users.
155

RSSI based self-adaptive algorithms targeting indoor localisation under complex non-line of sight environments

Hou, Xiaoyue January 2018 (has links)
Location Based Services (LBS) are a relatively recent multidisciplinary field which brings together many aspects of the fields of hardware design, digital signal processing (DSP), digital image processing (DIP), algorithm design in mathematics, and systematic implementation. LBS provide indirect location information from a variety of sensors and present these in an understandable and intuitive way to users by employing theories of data science and deep learning. Indoor positioning, which is one of the sub-applications of LBS, has become increasingly important with the development of sensor techniques and smart algorithms. The aim of this thesis is to explore the utilisation of indoor positioning algorithms under complex Non-Line of sight (LOS) environments in order to meet the requirements of both commercial and civil indoor localisation services. This thesis presents specific designs and implementations of solutions for indoor positioning systems from signal processing to positioning algorithms. Recently, with the advent of the protocol for the Bluetooth 4.0 technique, which is also called Bluetooth Low Energy (BLE), researchers have increasingly begun to focus on developing received signal strength (RSS) based indoor localisation systems, as BLE based indoor positioning systems boast the advantages of lower cost and easier deployment condition. At the meantime, information providers of indoor positioning systems are not limited by RSS based sensors. Accelerometer and magnetic field sensors may also being applied for providing positioning information by referring to the users' motion and orientation. With regards to this, both indoor localisation accuracy and positioning system stability can be increased by using hybrid positioning information sources in which these sensors are utilised in tandem. Whereas both RSS based sensors, such as BLE sensors, and other positioning information providers are limited by the fact that positioning information cannot be observed or acquired directly, which can be summarised into the Hidden Markov Mode (HMM). This work conducts a basic survey of indoor positioning systems, which include localisation platforms, using different hardware and different positioning algorithms based on these positioning platforms. By comparing the advantages of different hardware platforms and their corresponding algorithms, a Received Signal Strength Indicator (RSSI) based positioning technique using BLE is selected as the main carrier of the proposed positioning systems in this research. The transmission characteristics of BLE signals are then introduced, and the basic theory of indoor transmission modes is detailed. Two filters, the smooth filter and the wavelet filter are utilised to de-noise the RSSI sequence in order to increase localisation accuracy. The theory behind these two filter types is introduced, and a set of experiments are conducted to compare the performance of these filters. The utilisation of two positioning systems is then introduced. A novel, off-set centroid core localisation algorithm is proposed firstly and the second one is a modified Monte Carlo localisation (MCL) algorithm based system. The first positioning algorithm utilises BLE as a positioning information provider and is implemented with a weighted framework for increasing localisation accuracy and system stability. The MCL algorithm is tailor-made in order to locate users' position in an indoor environment using BLE and data received by sensors locating user position in an indoor environment. The key features in these systems are summarised in the following: the capacity of BLE to compute user position and achieve good adaptability in different environmental conditions, and the compatibility of implementing different information sources into these systems is very high. The contributions of this thesis are as follows: Two different filters were tailor-made for de-nosing the RSSI sequence. By applying these two filters, the localisation error caused by small scale fading is reduced significantly. In addition, the implementation for the two proposed are described. By using the proposed centroid core positioning algorithm in combination with a weighted framework, localisation inaccuracy is no greater than 5 metres under most complex indoor environmental conditions. Furthermore, MCL is modified and tailored for use with BLE and other sensor readings in order to compute user positioning in complex indoor environments. By using sensor readings from BLE beacons and other sensors, the stability and accuracy of the MCL based indoor position system is increased further.
156

Análise e desenvolvimento de comunicação e computação móvel em sistemas de automação

Fernandes, Gustavo Manuel Ferreira January 2004 (has links)
Tese de mestrado. Faculdade de Engenharia. Universidade do Porto. 2004
157

Aplicações bluetooth e perspectivas de evolução : um novo serviço de emergência em plataformas open-source

Couto, Adelino António Vale Vieira do January 2008 (has links)
Tese de mestrado. Redes e Serviços de comunicação. Faculdade de Engenharia. Universidade do Porto. 2008
158

Evaluating Bluetooth Radio for Physiological Monitoring

AL-Ramadan, Aymen January 2018 (has links)
Globally, population numbers are growing, and the lifespan of the elderly is increasing. Therefore, this phenomenon requires that society commit more money, facilities, and staff for health care. The Internet of Things (IoT) can be employed to cover the financial shortfall in healthcare resources by using sensors for remote health monitoring such as the Shimmer device. The Shimmer physiological sensor is a Bluetooth-enabled radio device designed and used for monitoring various human health conditions. Using a sufficient number of the Shimmer devices with proper sampling rate can affect the provision of health and related information in realtime. Moreover, this type of sensor can sometimes be attached to the human body, which can create an inference between the sensors and the human body. The high-noise environment may also impact the sensor. This thesis reviews and analyses several scenarios in which Shimmer devices can be used by medical practitioners to offer reliable physiological measurements, such as ECG and movement. This study found that the Shimmers device can provide reliable data by using a specific configuration when the maximum number of sensors participate in a piconet network.
159

Simulator Oriented Control of Power in Bluetooth Wireless Sensor Networks

García, Manuel, Chicharro, Francisco Javier January 2009 (has links)
<p>Create our own simulator much more oriented to Bluetooth networks, we will program the simulator in Java language and a graphical environment through Java. Fully modular and open so it can be expanded with more tools that we could develop. Initially the simulator will not work with all the specifications of Bluetooth, we will focus on the Bluetooth 2.0+EDR version. It will be only a demo version with several features working properly.</p>
160

En kombination av Bluetooth och LabVIEW för ett universellt mätdatorsystem inom medicinsk teknik / A combination of Bluetooth and LabVIEW for a universal data acquisition system within medical science

Hjelm-Andersson, Alexander January 2004 (has links)
<p>Examensarbetet är utfört på Linköpings Universitet, Institutionen för Medicinsk Teknik och bygger på att undersöka möjligheterna för trådlös överföring av mätvärden via Bluetooth. Mätningarna gäller två olika hårdvaror som med metoden PPG mäter blodflöde, en ny förenklad hårdvara och en mer avancerad och tidigare utvecklad hårdvara. Arbetet är tvådelat, under första delen upprättades en kommunikation med Bluetooth och två metoder för överföring av data undersöktes. Under andra delen togs ett gränssnitt fram i utvecklingsmiljön LabVIEW för styrning av hårdvarorna samt för åskådliggörandet av mätdata. Metoderna som undersöktes för dataöverföring är att antingen kontinuerligt skicka samplat data direkt från en AD-omvandlare eller att fylla bluetoothmodulens minne för att därefter skicka samtliga värden samtidigt. För utvärdering av vilken metod som passar bäst för ändamålet diskuteras för- och nackdelar, samplingshastigheter undersöks och redovisas med hjälp av tabeller och grafer. Examensarbetet har resulterat i en grund för fortsatt utveckling av trådlös anpassning av mättekniska ändamålinom medicinsk teknik.</p>

Page generated in 0.3505 seconds