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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.
41

Memory Measurement and Message Usage Improvement on an Elevator Embedded System

Arleklint, Tomas January 2019 (has links)
All embedded systems are unique, a design that is suitable for one system can rarely be copied over to another. This inherently makes designing embedded systems difficult. The difficulty is only amplified by the uncertainty of the future requirements as it is developed over time. Being able to continuously validate the performance and the reliability is of great importance to be able to ensure fault proof execution.This thesis explores two areas. A method of tracking the static and dynamic memory usage of a system is crucial to ensure correct functionality under all conditions, and that the implemented hardware will suffice. Multiple possible tools, each functioning uniquely, were developed and tested to find the most suitable for measuring the memory usage of the elevator system. Additionally the message usage, i.e. the way the different units within the studied system communicate with each other, was scrutinized for possible performance and reliability enhancements. A study was made for the most optimal communication protocol, and for how the transmissions could be improved upon.The results show that for this specific system, the best way of calculating the memory usage is with a tool developed within this project. Using this tool it was found that none of the modules in the elevator system use more than 30 % of the available memory during execution. The message usage study shows the most optimal protocol is CAN with the ISO 15765-2 upperlevel protocol, which is the one currently in use. However, improvements to the message transmissions are suggested, such as taking full advantage of the CAN protocol and by implementing message buffers on the receiving end.An important conclusion is that just as there is no unique system design that fits all, there is no memory measurement tool or message usage implementation that fits all systems. Each system has to be analyzed to find the most optimal solution for that particular system. / Alla inbyggda system är unika, en design som passar ett system kan sällan kopieras över till ett annat. Detta leder till att det är svårt att designa inbyggda system. Osäkerheten över framtida systemkrav då systemet utvecklas över tid gör inte designproblemet lättare. Att kontinuerligt kunna validera prestandan och pålitligheten är viktigt för att kunna garantera felfri körning.Detta examensarbete utforskar två områden. En metod för att mäta den statiska och dynamiska minnesanvändningen av systemet är nödvändig för att kunna säkerställa att systemet alltid fungerar som det ska, och att den tillgängliga hårdvaran är tillräcklig. Flera olika verktyg utvecklades och testades för att hitta det som bäst mäter hissens minnesanvändning. Utöver det granskades meddelandeanvändningen, hur de olika enheterna inom det studerade systemet kommunicerar med varandra, för potentiella förbättringar av prestandan och pålitligheten. En studie utfördes för att hitta det mest optimala kommunikationsprotokollet, och för hur av överföringarna kunde förbättras.Resultatet visar att för det här specifika systemet är bästa sättet att räkna ut minnesanvändningen med ett verktyg utvecklat under projektet. Med hjälp av det här verktyget visas att ingen av modulerna i hissystemet använde mer än 30% av det tillgängliga minnet under körning. Studien över minnesanvändningen påvisar att det mest optimala protokollet var CAN och ISO 15765-2 för det övre lagret, vilket är det som används för nuvarande. Dock föreslås förbättringar till hur meddelandena överförs, till exempel genom att utnyttja CAN protokollet till fullo och genom att implementera meddelandebufferts på mottagarsidan.En betydelsefull slutsats som drogs var att på samma sätt som det inte finns en unik systemdesign som passar alla system, finns det inte heller ett minnesanvändningsverktyg eller en meddelandeanvändning som passar alla system. Varje enskilt system måste analyseras för att hitta den mest optimala lösningen för det specifika systemet.
42

Streamlining UAV Communication : Investigating and implementing an accessible communication interface between a ground control station and a companion computer

Gustafsson, Johan, Mogensen, Daniel January 2023 (has links)
In the future, the usage of UAVs (Unmanned Aerial Vehicles) will be applied in many different areas. Continued research in UAVs can benefit through its applications in disaster response, humanitarian aid, environmental monitoring, infrastructure inspection, improved transportation and delivery systems, and scientific research. By leveraging UAV technology and making the technology easier to get into, we can enhance efficiency, safety, and accessibility in various fields while addressing critical global challenges and improving the well-being of individuals and communities. The entry knowledge needed for starting development with UAVs can be high due to the complex communication needed between a ground station and the UAV. This report has the goal of lowering that entry barrier by doing an investigation of some available communication protocols, choosing a protocol and using said protocol to develop and implement an interface for communication between a ground control station and companion computer onboard an UAV. The investigation of communication protocols for UAVs indicated that the widely used Mavlink protocol is the best suited communication protocol for this implementation. The development and iterative process, carried out with the mentioned protocol and a UAV flight controller, resulted in the creation of an artifact that can serve as the desired interface.
43

Sårbarhetsanalys av IKEA TRÅDFRI rörelsesensor / Vulnerability analysis of IKEA TRÅDFRI motion sensor

Hyrkäs, Nathalie, Karlsson, Erik January 2021 (has links)
Arbetet utvärderar Ikea TRÅDFRI rörelsesensors kommunikationsprotokoll utifrån ett säkerhetsperspektiv. Internet of Things expanderar och i takt med utvecklingen är det viktigt att granska produkter på marknaden för att se hur säkerhet är implementerat. I rapporten utforskas flera olika sätt att utvärdera produkten för att få en god helhetsbild. Detta innefattar metoder kring hur en obehörig kan få tillgång till information genom avlyssning, ifall en obehörig skulle kunna ta över kommunikationen genom att parkoppla till en ljuskälla på ett långt avstånd samt en bedömning av sårbarhetsgrad utifrån Totalförsvarets forskningsinstituts kartläggning. Resultatet påvisar möjligheten att utnyttja enheten genom en sidokanalsattack samt hur parkoppling kan ske på ett längre avstånd än vad som enligt specifikationen ska vara möjligt. / This report evaluates the Ikea TRÅDFRI motion sensor communication protocol from a security point of view. Internet of Things is constantly expanding and with its growth it is important to examine products on the market to see how security is implemented. Different options on ways to evaluate the product is explored in the report. That includes methods of how an unauthorized person could gain access to information through eavesdropping, if they could take over the communication by pairing to a light source from a long distance, and an assessment of the degree of vulnerability by Totalförsvarets forskningsinstitut. The results show that it is possible to exploit the device through a side-channel attack and also how pairing is enabled on a longer distance than what is specified.
44

Solbil : Designundersökning av övervakningssystem och automatisk energiförbrukningsprognos för en solbil / Solar car : Design study of a monitoring system and automatic energy consumption forecasting for a solar car

Eriksson, Klas-Göran, Peterson, Andreas January 2017 (has links)
Jönköping University Solar Team deltog år 2015 i tävlingen World Solar Challenge som körs vartannat år i Australien. Team från hela världen deltar i denna tävling där de konstruerar solbilar som de sedan tävlar med i ett race på ca 3000 km från Darwin till Adelaide. En solbil är en elbil som även är utrustad med solpaneler för att ge en teoretiskt oändlig körsträcka så länge bilen har tillgång till solenergi. Jönköping University kom på 15 plats i detta race och ville till nästa race förbättra sin konkurrenskraft. Eftersom det var ett race och varje teams mål var att använda sin bil så effektivt som möjligt behövdes ett system för att övervaka och logga batteridata och presentera det för teamet. Det var även fördelaktigt om teamet kunde få någon form av energiprognos för att kunna bestämma vilken hastighet som solbilen bör hålla. Ett system som loggar och överför denna information från solbilen till en följebil utvecklades och utvärderades. Syftet med denna studie var således: Öka Jönköping University Solar Teams konkurrenskraft genom att förse följebilen med ett beslutsstöd som i realtid övervakar och loggar solbilens batterinivå och energiförbrukning. Design Science Research användes som metod för att genomföra detta syfte, vilket gav möjligheten att utveckla systemet som en artefakt och använda denna för att presentera resultatet. Tre olika experiment utfördes för att konstatera funktionaliten på den trådlösa kommunikationen, hur rättvisande systemet var samt hur väl energiförbrukningen kunde förutsägas. I resultatet beskrivs hela artefakten och tillsammans med experimenten konstaterades att systemet kommer att ge Jönköping University Solar Team en högre konkurrenskraft i nästa race. / Jönköping University Solar Team participated in the 2015 edition of World Solar Challenge, which is held every other year in Australia. Teams from all around the world participates in the competition in which they construct a solar car and competes in a 3000 km long race from Darwin to Adelaide. A solar car is an electric car equipped with solar panels to give it a theoretical infinite mileage as long as the car have access to solar energy. Jönköping University came in 15th place in this race and would like to improve their competitiveness in the next race. Because it is a competition and the goal for every team is to use their car as efficiently as possible a system to log and monitor the battery and present the information to the team was needed. It would also be good to have some kind of energy consumption forecast that would be used to decide the speed the solar car should keep. A system that collect, stores and transmits the information from the solar car to an escort vehicle was developed and evaluated. Thus, the pursues of this studies were: Improve Jönköping University Solar Teams competitiveness by provide a decision support which in real time monitor and log the solar car battery level and energy consumption. Design Science Research was used as a method to realize this purpose, which gave the opportunity to develop the system as an artifact and use this to present the result. Three different experiments were constructed to determine the functionality of the wireless communication, how accurate the system was and how well the energy consumption could be predicted. In the results the artifact is described as a whole and together with the experiments it is found that the system will give Jönköping University Solar Team a higher competitiveness in the next race.
45

Un environnement pour le calcul intensif pair à pair / An environment for peer-to-peer high performance computing

Nguyen, The Tung 16 November 2011 (has links)
Le concept de pair à pair (P2P) a connu récemment de grands développements dans les domaines du partage de fichiers, du streaming vidéo et des bases de données distribuées. Le développement du concept de parallélisme dans les architectures de microprocesseurs et les avancées en matière de réseaux à haut débit permettent d'envisager de nouvelles applications telles que le calcul intensif distribué. Cependant, la mise en oeuvre de ce nouveau type d'application sur des réseaux P2P pose de nombreux défis comme l'hétérogénéité des machines, le passage à l'échelle et la robustesse. Par ailleurs, les protocoles de transport existants comme TCP et UDP ne sont pas bien adaptés à ce nouveau type d'application. Ce mémoire de thèse a pour objectif de présenter un environnement décentralisé pour la mise en oeuvre de calculs intensifs sur des réseaux pair à pair. Nous nous intéressons à des applications dans les domaines de la simulation numérique et de l'optimisation qui font appel à des modèles de type parallélisme de tâches et qui sont résolues au moyen d'algorithmes itératifs distribués or parallèles. Contrairement aux solutions existantes, notre environnement permet des communications directes et fréquentes entre les pairs. L'environnement est conçu à partir d'un protocole de communication auto-adaptatif qui peut se reconfigurer en adoptant le mode de communication le plus approprié entre les pairs en fonction de choix algorithmiques relevant de la couche application ou d'éléments de contexte comme la topologie au niveau de la couche réseau. Nous présentons et analysons des résultats expérimentaux obtenus sur diverses plateformes comme GRID'5000 et PlanetLab pour le problème de l'obstacle et des problèmes non linéaires de flots dans les réseaux. / The concept of peer-to-peer (P2P) has known great developments these years in the domains of file sharing, video streaming or distributed databases. Recent advances in microprocessors architecture and networks permit one to consider new applications like distributed high performance computing. However, the implementation of this new type of application on P2P networks gives raise to numerous challenges like heterogeneity, scalability and robustness. In addition, existing transport protocols like TCP and UDP are not well suited to this new type of application. This thesis aims at designing a decentralized and robust environment for the implementation of high performance computing applications on peer-to-peer networks. We are interested in applications in the domains of numerical simulation and optimization that rely on tasks parallel models and that are solved via parallel or distributed iterative algorithms. Unlike existing solutions, our environment allows frequent direct communications between peers. The environment is based on a self adaptive communication protocol that can reconfigure itself dynamically by choosing the most appropriate communication mode between any peers according to decisions concerning algorithmic choice made at the application level or elements of context at transport level, like topology. We present and analyze computational results obtained on several testeds like GRID’5000 and PlanetLab for the obstacle problem and nonlinear network flow problems.
46

Desenvolvimento e implementação de um sistema de controle de posição e velocidade de uma esteira transportadora usando inversor de frequência e microcontrolador /

Raniel, Thiago. January 2011 (has links)
Orientador: Jozué Vieira Filho / Banca: Carlos Antonio Alves / Banca: Tony Inácio da Silva / Resumo: A automação de esteiras rolantes é algo comum e importante em sistemas industriais, mas problemas práticos ainda representam desafios. Um dos desses desafios é manter a precisão em sistemas que exigem paradas sistemáticas, pois folgas mecânicas tendem a provocar variações nas posições de paradas ao longo do tempo. A aplicação de motores de indução têm se tornado comum e soluções eficientes e de baixo custo têm sido pesquisadas. Neste trabalho foi desenvolvido e implementado um sistema de controle de posição e velocidade aplicado em esteiras transportadoras utilizando inversor de frequência, microcontrolador, encoder óptico incremental e sensor indutivo. O movimento da esteira transportadora é efetuado por um motor de indução trifásico, que é acionado pelo conjunto microcontrolador - inversor de frequência. Este conjunto impõe uma frequência no estator do motor através de uma troca de mensagens entre microcontrolador e inversor de frequência (Sistema Mestre-Escravo). Para o envio e recebimento das mensagens, utilizou-se o protocolo de comunicação serial USS® (Universal Serial Interface Protocol) através do padrão RS-485. Os controles de posição e velocidade de rotação do eixo do motor fundamentam-se no sinal gerado pelo encoder óptico incremental, responsável por informar a posição do eixo do motor ao longo da trajetória, e no sensor indutivo que determina uma referência externa importante para a esteira transportadora. Para o funcionamento automático da esteira, elaborou-se um software em linguagem de programação C. Como resultado obteve-se um sistema de controle de posição e velocidade do eixo do motor de indução trifásico que apresenta bons resultados / Abstract: Automated conveyors system have been largely used in industrial applications. However, there are still practical issues to be overcome. One of them is due to the system mechanical limitation which can lead to low accuracy for applications based on "stop-and-go" movements. Induction motors have been largely used in such applications and low costs solutions have been searched. In this work it was developed and implemented a system of positioning and velocity control applied to conveyors which is based on frequency inverter, microcontroller, optical incremental encoder and inductive sensor. The conveyor's movement is made by means of a three-phase induction motor, which is driven by the couple microcontroller-frequency inverter. There are messages exchange between the microcontroller and the frequency inverter (Master - Slave configuration) which is based on the communication serial protocol USS through the RS-485 standard. The position and velocity of the motor spindle are controlled using an optical incremental encoder, which is responsible to provide the position of the trajectory, and an inductive sensor which determines the initial reference to the conveyor. The software used to control the system was developed in C language. The results show a low cost system with good results / Mestre
47

Design and Analysis of Real-time Message Scheduling under FlexRay Protocol

Sunil Kumar, P R January 2017 (has links) (PDF)
A typical automobile system consists of many Electronic Control Units (ECUs) for the purposes of safety, comfort, and entertainment applications. FlexRay is a high bandwidth protocol for such automotive requirements, which facilitates communication between distributed ECUs. This thesis addresses some of the issues associated with the design and implementation of the FlexRay protocol. The number of ECUs that are used in automobiles has an increasing trend to implement more functionality, which demands more bandwidth. By minimizing bandwidth requirements for servicing a given workload of periodic and sporadic real-time tasks, one can connect more ECUs to the same FlexRay bus. With this motivation, the first part of this thesis proposes new algorithms for minimizing bandwidth usage of ECUs in both the static and the dynamic segments of FlexRay. FlexRay provides a time-triggered static segment for the transmission of time critical periodic messages. The static segment consists of a fixed number of static slots each with a fixed duration. The duration of the static slot and the number of slots are design parameters which need to be fixed so as to meet all the deadline requirements of the workload in the application. The static slot duration can be minimized by packing the signals into message frames, while respecting scheduling constraints. Since message frames also contain overhead information, the duration of message frames can be optimized by proper signal packing, based on the network utilization constraints of individual ECUs. The thesis proposes a novel algorithm for packing of signals into message frames and fixing the static slot duration so that the total duration of the static segment is minimized. The dynamic segment of FlexRay caters to the transmission of event-triggered signals. A novel algorithm has been proposed to obtain the minimum duration of the dynamic segment while meeting the deadline constraints of all sporadic messages in their worst-case arrival instances. We also extend all these algorithms to the case of slot multiplexing scheme provided by FlexRay 3.0. Modern automobiles provide infotainment and in-car telemetry functions, which produce a high volume of soft deadline messages. This makes the problem of analyzing scheduling algorithms for such traffic important. The dynamic segment of the FlexRay cycle is used for transmission of such soft deadline messages. The second part of this thesis addresses the issue of analyzing the quality of performance in servicing of the soft deadline tasks in the FlexRay protocol. Two quality measures, namely, the average delay in servicing of the soft deadline tasks and the fraction of tasks that miss their deadlines, are considered. The generation of different soft deadline messages is modeled as independent Poisson processes. The generated messages are queued in different queues and are serviced according to pre-assigned priorities for different queues as per the FlexRay protocol. By analyzing this multiple queue model under some mild assumptions, upper bounds on the arrival rates for different messages are derived so that all the queues are stable. Analytical expressions are also derived for average delay and for deadline miss ratio. The correctness of these approximate analytical expressions are demonstrated through simulation studies.
48

Interoperabilitet: En väg till samordnade transporter? / Interoperability: An approach to coordinated transports?

Larsson, Niklas, Carlsson, Alexander, Levin Brunell, Alexander January 2017 (has links)
Digitaliseringens utveckling genomsyrar stora delar av samhället där informationsteknologi bidragit till tidigare otänkbara möjligheter och fördelar. I dagsläget har organisationer rationaliserat flertalet affärsprocesser där teknologin anses utgöra en fundamental utgångspunkt. Informationsteknologins framfart medför förändringar kring kommunikation där begreppet interoperabilitet introduceras som: samverkan mellan två eller fler system med motivet att utbyta information. Vidare har cirkulär ekonomi erhållit mer uppmärksamhet under senare år där motivet är att förbättra problematiken kring resurshantering och återvinning. Den här studien syftar till att skapa grunden för utformningen av ett informationssystem med stöd av ett interoperabilitetsramverk där motivet är att understödja verksamheter vid sambokningstransporter. Det här har genomförts med hjälp av en kvalitativ forskningsansats där intervjuer har nyttjats som datainsamlingsmetod där studien har avgränsats till mikro-, små- och medelstora organisationer. Dessa är belägna inom en glest befolkad kommun i Sverige där företagsrepresentanter från Orust kommun bidragit med empirisk data. / The evolution of digitization permeates large parts of society where information technology has contributed to previously unthinkable possibilities and benefits. At present, organizations have rationalized most business processes where technology is considered to be a fundamental starting point. The advancement of information technology brings about changes in communication where the concept of interoperability is introduced as: collaboration between two or more systems with the purpose of exchanging information. In addition, circular economics have gained more attention in recent years, the purpose of which is to improve the problem of resource management and recycling. This study aims to provide the basis for the design of an information system, supported by an interoperability framework, with the purpose of supporting co-transport activities. This has been done using a qualitative research effort where interviews have been used as a data collection method in which the study has been delimited to micro, small and medium-sized organizations. These are located within a sparsely populated municipality in Sweden, where business representatives from Orust Municipality contributed empirical data.
49

Improving medium access for dynamic wireless sensor networks / Améliorations de l'accès au medium dans les réseaux dynamiques de capteurs sans fils

Papadopoulos, Georgios 28 September 2015 (has links)
L’Internet des objets amène des contraintes uniques et une immense variété d’applications. Ceci oblige à être capable d’établir des communications efficaces en énergie (et néanmoins à faible délai) au sein de réseaux fortement dynamiques. Nous nous sommes concentrés sur l'amélioration du contrôle d'accès au medium (MAC), afin d’optimiser la gestion des communications sans fils,principale source de consommation d'énergie dans ces réseaux. Cette thèse discute de l’auto adaptation de solutions MAC asynchrones et montre qu’une coopération localisée entre objets communicants permet de maintenir un partage efficace de la ressource de communication face à une forte dynamique (trafic, mobilité, pannes). Outre une réflexion menée sur les outils de simulation et d'expérimentation, nous avons conduit des campagnes d'évaluations complètes de nos contributions qui traitent tant des changements de trafic que de la mobilité dans les réseaux très denses. / The Internet of Things brings unique constraints and a huge variety of applications. This forces to be able to establish energy efficient communications (and never the less low-delay) within highly dynamic networks. We focused on improving the medium access control (MAC) to optimize the management of wireless communications, the main source of energy consumption in these networks. This thesis discusses the self-adaptation of asynchronous MAC solutions and shows that a localized cooperation between communicating objects can maintain an efficient sharing of the communication resource in highly dynamic networks (traffic, mobility, failures). In addition to a reasoning on the tools of simulation and experimentation, we conducted comprehensive evaluation campaigns of our contributions that address traffic changes and mobility in dense networks.
50

Flight Software Development for Demise Observation Capsule

Zamouril, Jakub January 2017 (has links)
This work describes the process of the design of a flight software for a space-qualified device, outlines the development and testing of the SW, and provides a description of the final product. The flight software described in this work has been developed for the project Demise Observation Capsule (DOC). DOC is a device planned to be attached to an upper stage of a launch vehicle and observe its demise during atmospheric re-entry at the end of its mission. Due to constraint on communication time during the mission and the need to maximize the amount of transferred data, a custom communication protocol has been developed. / Demise Observation Capsule

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