• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 29
  • 18
  • 17
  • 8
  • 3
  • 3
  • 2
  • 2
  • Tagged with
  • 87
  • 87
  • 29
  • 28
  • 14
  • 14
  • 13
  • 13
  • 11
  • 11
  • 11
  • 11
  • 9
  • 8
  • 8
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Implementace rozhraní IO-Link do snímačů tlaku / IO/Link interface implementation to pressure sensors

Pešl, Jiří January 2014 (has links)
This thesis is concerned with the measurement of physical quantities. Thesis describes sensors in general terms and requirements, which delivers latest trends in the field of automation. The main theme of this thesis is sensors for meassuring pressure, and their connection to the automation chain. In the next part thesis describes the design of the converter for connecting SMART sensors for pressure measuring, that use HART communication protocol, to the automation systems managed by a communication protocol IO-link. First will be described in detail various communication standards by their ISO OSI model, and on this theoretical basis will be based design of converter between communication protocol HART and communication protocol IO-Link. The last part will be Designed software for this converter.
22

Malá testovací teplotní komora / Small Temperature Test Chamber

Wolfshörndl, Robert January 2014 (has links)
This diploma thesis deals with the design of a small temperature test chamber. The first chapter is a study of temperature sensors suitable for realization of temperature chambers. The conclusion of this chapter is devoted to digital temperature sensor DS18B20. The second chapter deals with the principles and basic parameters of Peltier cells. In the third chapter design of individual electronic components of the temperature chamber is realized (circuit diagrams and PCBs), including a description of basic features of the microcontroller firmware. The fourth chapter is devoted to a description of the basic properties of the application software and a description of the communication protocol. The last two chapters deal with the construction of the temperature chamber and the results of final functional test.
23

Návrh a implementace komponenty pro komunikaci s PCI rozhraním / Design and Implementation of the Component for Comunication with PCI Interface

Janoušek, Michal January 2011 (has links)
This masters thesis deals with design of the component facilitating communication between PCI bus and user component. Designed component is simplifying the communication protocol between designed and user components, while advanced functions of PCI bus are preserved. Target platform is COMBO6-PTM card containing FPGA with Spartan 3 technology. Communication with PCI bus is mediated by PLX component. Thesis also contains design of simplified communication protocol.
24

Optimalizace komumikačních protokolů / Communication Protocol Optimization

Buno, Petr January 2015 (has links)
This thesis deals with smart home issue, analyzes existing solutions and is focused on the system that is developed in collaboration with FIT VUT in Brno. The emphasis is on the description of client application for control and monitoring of smart home system. Furthermore, the work discussed base theoretical knowledge from internet communication field, which is closely related to these issues. The core of the work is to design a communication protocol between the server and a mobile device. Finally, the work also includes a description of a network layer at the device using this protocol. The last part is devoted to testing and evaluation of the final solution.
25

Jämförelse av OPS, MQTT och DDS med avseende på fördröjningstid och throughput / Comparison of OPS, MQTT and DDS with regards to latency and throughput

Nilsson, Kasper, Bergman, Alicia January 2023 (has links)
In this study a comparison of the publish-subscribe communication protocols OPS, MQTT and DDS were conducted. The implementation used for DDS was fastDDS and the client library Paho Eclipse MQTT C++ was used for MQTT with the broker implementation Eclipse Mosquitto. The goal was to see which out of these protocols performs best in a peer-to-peer communication scenario when it comes to latency and throughput with varying payload size. Two experiments were carried out. The first experiment measures the round-trip-time of a message and is realized by a ping-pong application. The latency was then calculated by taking half of the round-trip-time. The second experiment was publishing messages from one client and being retrieved by another and counting the amount of messages being retrieved in one second. To get bytes per second the payload size was multiplied by the amount of messages retrieved by the subscriber. The result of the first experiment showed that OPS with the underlying transport protocol TCP had the most favorable result. For the second experiment OPS with UDP as the transport protocol had the highest throughput in most cases however for the highest payload used in the experiment fastDDS with UDP had the highest throughput. However, the results gave substantial differences between the protocols in regards to throughput which indicate that the configuration might not be optimal for a fair comparison. Further research of this is recommended before making a final conclusion in regards to the overall results. / I denna studie genomfördes en jämförelse av kommunikationsprotokollen OPS, MQTT och DDS. Implementeringen som användes för DDS var fastDDS och klientbiblioteket Paho Eclipse MQTT C++ användes för MQTT med Eclipse Mosquitto som broker. Målet var att se vilket av dessa protokoll som fungerar bäst i ett peer-to-peer-kommunikationsscenario när det gäller fördröjningstid och throughput med varierande payloadstorlek. Två experiment utfördes. Det första experimentet mäter round-trip-time för ett meddelande och realiseras av en ping-pong-applikation. Fördröjningstiden beräknades sedan genom att ta hälften av round-trip-time. Det andra experimentet var att publicera meddelanden från en klient och mottas av en annan och räkna mängden meddelanden som mottas på en sekund. För att få byte per sekund multiplicerades payload storleken med mängden meddelanden som togs emot av prenumeranten. Resultatet av det första experimentet visade att OPS med det underliggande transportprotokollet TCP hade det mest gynnsamma resultatet. För det andra experimentet hade OPS med UDP som transportprotokoll den högsta throughput i de flesta fall, men för den största payloadstorleken som användes i experimentet hade fastDDS med UDP den högsta. Resultaten gav dock betydande skillnader mellan protokollen när det gäller throughput som indikerar att konfigurationen kanske inte är optimal för en rättvis jämförelse. Ytterligare forskning om detta rekommenderas för att utreda orsaken till dessa skillnader och därefter kunna skapa konfigurationer som ger rättvisa förutsättningar för en optimal jämförelse.
26

Komunikační systém malého mobilního robotu / Communication System of Small Mobile Robot

Petrov, David January 2012 (has links)
This thesis addresses the problem of wireless transmission between the operator station and the robot. There is a solution presented by way of testing the parameters of wireless modules, compare them in the environment and the draft protocol.
27

Protocolo de comunicação segura para plataforma de distribuição de vídeo em redes sobrepostas. / Protocol of secure communication for video distribution platform on overlay networks.

Pimentel, Hélcio Machado 07 July 2011 (has links)
As redes de distribuição de vídeo têm sido amplamente utilizadas na atualidade pela Internet. O sucesso de Portais de Vídeo evidencia tal uso. Por poderem ser redes de grande porte, há uma grande preocupação com as vulnerabilidades existentes nessas redes. A comunicação de seus elementos deve ser segura o bastante para garantir a disponibilidade, o sigilo e integridade de suas mensagens e a autenticidade dos seus elementos. Este trabalho apresenta um protocolo de comunicação segura que busca atender a tais necessidades de uma maneira eficiente - pois consegue atender aos requisitos de desempenho na entrega do conteúdo aos usuários - e genérica - pois pode ser utilizado em outras plataformas de distribuição. A validação do trabalho é feita de maneira a mostrar que a proposta consegue atender aos requisitos de um sistema de distribuição de vídeo seguro. / Video delivery network has been widely used across the Internet nowadays. The success of Video Portals is an evidence of this use. Due to its potential to turn into large infrastructures, there is a concern about its vulnerabilities. The communication among its elements must be secure enough to guarantee the availability, the secrecy and integrity of messages and the authenticity of its elements. We present in this work a secure communication protocol to meet such requisites in an efficient - since it meets the performance requisites for delivering the content to the users - and generic way - because it can be used by other distribution systems. The validity of this work is done in order to show that this proposal can meet the requisites of a secure video delivery system.
28

Ajuste baseado em dados de controladores : o método VRFT embarcado em um aplicativo móvel

Garcia, Cristiane Silva January 2017 (has links)
O método VRFT (Virtual Reference Feedback Tuning) é um método baseado em dados utilizado para ajustar os parâmetros de um controlador. Uma das vantagens deste método é que não é necessário um conhecimento detalhado do modelo do processo a ser controlado. Neste trabalho é apresentado o desenvolvimento de um aplicativo Android que utiliza o método VRFT, e uma versão recursiva do mesmo, para ajustar os parâmetros de um controlador PID com base nos dados de entrada e saída coletados de um experimento realizado no processo. O experimento pode ser configurado, inicializado, monitorado, e interrompido através da aplicação móvel. Para viabilizar a comunicação com o controlador também foram desenvolvidos um gateway Bluetooth-Modbus e um protocolo de comunicação simples, que opera sobre o serviço de comunicação serial do protocolo Bluetooth. A solução proposta foi validada através de experimentos realizados em processos simulados e em um processo real, mostrando bons resultados em ambos os casos. / The Virtual Reference Feedback Tuning (VRFT) method is a data-driven method employed to tune the parameters of a controller. An advantage of this method lies in the fact that it does not need a detailed knowledge of the process model. This work presents the development of an Android application which employs the VRFT method and a newly developed recursive version of it to tune a PID controller based upon the data collected from an experiment conducted on the process. The experiment can be set up, started, monitored, and stopped from inside the mobile application. To communicate with the controller a Bluetooth-Modbus gateway and an application layer protocol, designed over the Bluetooth serial communication service, are employed, both newly developed. Finally, the entire solution is verified in two steps: first some experiments were conducted on a simulated process, then another experiment was conducted to tune a real commercial controller, both showing good results.
29

Protocolo de comunicação segura para plataforma de distribuição de vídeo em redes sobrepostas. / Protocol of secure communication for video distribution platform on overlay networks.

Hélcio Machado Pimentel 07 July 2011 (has links)
As redes de distribuição de vídeo têm sido amplamente utilizadas na atualidade pela Internet. O sucesso de Portais de Vídeo evidencia tal uso. Por poderem ser redes de grande porte, há uma grande preocupação com as vulnerabilidades existentes nessas redes. A comunicação de seus elementos deve ser segura o bastante para garantir a disponibilidade, o sigilo e integridade de suas mensagens e a autenticidade dos seus elementos. Este trabalho apresenta um protocolo de comunicação segura que busca atender a tais necessidades de uma maneira eficiente - pois consegue atender aos requisitos de desempenho na entrega do conteúdo aos usuários - e genérica - pois pode ser utilizado em outras plataformas de distribuição. A validação do trabalho é feita de maneira a mostrar que a proposta consegue atender aos requisitos de um sistema de distribuição de vídeo seguro. / Video delivery network has been widely used across the Internet nowadays. The success of Video Portals is an evidence of this use. Due to its potential to turn into large infrastructures, there is a concern about its vulnerabilities. The communication among its elements must be secure enough to guarantee the availability, the secrecy and integrity of messages and the authenticity of its elements. We present in this work a secure communication protocol to meet such requisites in an efficient - since it meets the performance requisites for delivering the content to the users - and generic way - because it can be used by other distribution systems. The validity of this work is done in order to show that this proposal can meet the requisites of a secure video delivery system.
30

Secure communications in wireless networks for biomedical EEG sensor networks applications. / Sécurisation des communications pour les réseaux de capteurs sans fil, application aux réseaux biomédicaux de type EEG.

Saleh, Mohammad 07 November 2018 (has links)
Le cadre général de la thèse concerne les réseaux de capteurs et la sécurisation des communications sans fil pour la mise en œuvre de systèmes fiables de surveillance orienté santé. Plus précisément, ce travail de thèse présente un nouveau système de surveillance biomédical à base de réseau de capteurs sans fil, pour la mesure de l'activité électrique du cerveau. Un réseau de capteurs sans fil de type EEG (électroencéphalogramme) permet de surveiller les ondes cérébrales spontanées, y compris les ondes normales et anormales, des patients souffrant de différents types d'épilepsie. Un capteur sans fil enregistre les signaux du patient (via le cuir chevelu) et filtre ces signaux et leurs données en parallèle selon un traitement approprié des ondes cérébrales. Il est dès lors possible de prédire la gravité d'une attaque épileptique à venir. Une première approche est proposée pour analyser les anomalies des ondes cérébrales et déclencher des alertes le cas échéant. De tels systèmes peuvent permettre de sauver de nombreux patients en prédisant l’arrivée les crises avant qu'elles ne surviennent et éviter ainsi les accidents et les comportements à risque lors d'une crise d'épilepsie. De plus, l’approche peut être utiliser pour d'autres mesures de diagnostic médical. Une autre approche basé sur l’apprentissage pour la prédiction en utilisant les réseaux de neurones de type FFNN (Feed Forward Neural Network ) est également présentée. Par ailleurs, Les approches de prédiction, exploitent la norme IEEE802.11n pour la transmission des données avec un protocole de confidentialité pour la sécurisation des communications. La mise en œuvre de la sécurité peut réduire considérablement le temps de la prédiction et retarder les signaux d’alerte des crises. Les mesures effectuées permettent la calibration des algorithmes de prédiction pour tenir compte des délais introduits par la sécurisation des communications. / The general framework of the thesis concerns sensor networks and the privacy protocols for wireless communications in the implementation of reliable healthcare systems. More precisely, it presents a novel biomedical wireless sensor Network monitoring system, as a predictor and advance sensitive portable electroencephalogram (EEG). The EEG wireless sensor network proposed to monitor spontaneous brain waves, including normal and abnormal waves, for the patients suffering from different types of epilepsy. The biomedical epilepsy wireless sensor Network monitoring system (WSN-EEG) read’s signals from a wireless sensor network on the patient scalp, and filter these signals to run parallel data processing for the brain waves. However, the predicting procedure for the severity of the forthcoming epileptic attack based on, a proposed mathematical model, which analyses the abnormality in the brain waves and alerts by giving signals for the patient. This method can save many patients by predicting the seizure before it occurs and helps them from different injuries and risky behavior arising during epilepsy attack. In addition, the proposed approaches can use the patient data for further medical diagnosis measures. Another approach is proposed as a learning-based approach for prediction using Feed Forward Neural Network (FFNN) for the alert system. The research used the IEEE802.11n as a communication method for the wireless sensor networks and measure the IEEE802.11n security performances as privacy protocol for data transmission of the proposed systems. The measurements indicated the calibration of the prediction algorithms to take account of the delays introduced by the security of the communications in the data transmission and seizure prediction which might significantly reduce prediction time and delay the alert signals.

Page generated in 0.157 seconds