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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.
31

Efficient super-peer-based coordinated service provision

Liu, M. (Meirong) 05 April 2014 (has links)
Abstract Peer-to-Peer (P2P) networks have been applied in many applications for sharing resources such as storage space, media files or network bandwidth. Their main benefits include decentralization, self-organization, and scalability. Moreover, P2P technologies are evolving towards hybrid systems, where P2P networks are used in those parts of a larger system to leverage the decentralization most efficiently. The examples include cloud computing, where P2P networks are used in sharing computing resources, and Machine-to-Machine communication, where P2P networks are used for resource discovery. In super-peer overlays, the nodes are either regular nodes or super nodes that are located higher in the node hierarchy. This type of overlay explores the heterogeneity of peers in the overlay network to enable applications to run more efficiently. Leveraging the advantage of a super-peer overlay for service provision is an important issue. This thesis contributes to the research and development of super-peer-based coordination service provision from three aspects. Firstly, a super-peer-based coordinated service provision framework is proposed to coordinate different service groups and service peers in resource sharing, aiming to enable service groups to adapt to dynamic service demands. The proposed framework is evaluated using the following performance metrics: service response time, scalability, robustness, and communication traffic, in comparison to related work. Secondly, an efficient algorithm for rapidly constructing a robust super-peer overlay is proposed. The algorithm introduces a super-peer candidate based method for super-peer selection and a two-hop search method for finding client peers. Performance evaluation takes into account the convergence time of building a super-peer overlay, communication overhead, scalability, robustness. A comparison to related work is also conducted. Thirdly, the architecture of distributed resource discovery based on P2P overlay for Machine-to-Machine service provision is proposed. The architecture supports heterogeneous devices using different communication protocols in resource registration and discovery for achieving interoperability. As a part of the thesis, a functional real-world prototype is implemented and verified with a simple demonstration. Preliminary evaluation on the prototype indicates that caching can improve the response time of resource lookup dramatically. / Tiivistelmä Vertaisverkkoja on hyödynnetty resurssien kuten tallennustilan, mediasisältöjen ja tietoliikennekapasiteetin jakamisessa. Niiden etuja perinteisiin keskitettyihin järjestelmiin verrattuna ovat hajautettu arkkitehtuuri, itseorganisoituvuus ja skaalautuvuus. Vertaisverkkoja käytetään yhä useammin järjestelmän osien toteuttamisessa, joissa hajautettujen resurssien hyödyntämisellä saavutetaan suurimmat edut. Esimerkkeinä ovat pilvilaskenta, jossa vertaisverkkoa käytetään laskentaresurssien jakamiseen, sekä laitteidenvälinen kommunikaatio, jossa vertaisverkkoja käytetään resurssien löytämiseen. Hierarkkisissa vertaisverkoissa niihin kytkeytyneet laitteet jaotellaan laitteiden kapasiteetin mukaan tavallisiin noodeihin ja näiden yläpuolella hierarkiassa toimiviin ylinoodeihin. Ylinoodeihin perustuva vertaisverkon kuoriverkko hyödyntää yksittäisten verkon noodien eli laitteiden erilaisuutta, jotta verkko voisi toimia tehokkaammin. Tämän ominaisuuden hyödyntäminen on erityisen tärkeää palvelun tarjonnassa. Tässä työssä on tutkittu ylinoodeihin perustuvan vertaisverkon palvelun tarjontaa kolmesta näkökulmasta. Ensimmäiseksi, työssä ehdotetaan ylinoodien koordinoimaa palveluntarjonnan toimintamallia resurssien jakamisessa. Toimintamallissa palveluryhmät ja palvelunoodit adaptoituvat dynaamisesti palvelupyyntöjen tarpeisiin. Tämän ratkaisun suorituskykyä arvioidaan palvelun vasteajan, skaalautuvuuden, robustisuuden ja tietoliikennemäärän suhteen verrattuna aiempiin ratkaisuihin. Toiseksi, työssä esitellään tehokas algoritmi robustin ylinoodikuoriverkon nopeaan muodostamiseen. Algoritmi käyttää ylinoodiehdokasmenetelmää ja kahden hypyn hakumetodia asiakasnoodien etsimisessä. Suorituskyvyn arvioinnissa otetaan huomioon ylinoodikuoriverkon konvergoitumisaika, tietoliikenneviestinnän aiheuttama ylimääräinen kuormitus, sekä järjestelmän skaalautuvuus ja robustisuus. Esitetyn algoritmin tehokkuutta arvioidaan vertaamalla näitä suorituskykymittareita aiempiin ratkaisuihin. Kolmanneksi, työssä esitellään hajautettu resurssihakemiston arkkitehtuuri, joka perustuu laitteiden välisen kuoriverkon palveluntarjontaan. Arkkitehtuuri tukee erilaisten laitteiden ja niiden käyttämien protokollien resurssien rekisteröintiä ja löytämistä yhteensopivuuden saavuttamiseksi. Väitöskirjatyön osana on toteutettu toimiva prototyyppi, jonka toimivuus on todennettu demonstraation avulla. Prototyypillä tehdyt mittaukset antavat perustellun syyn olettaa, että esitetyn ratkaisun mukainen välimuistin käyttö voi merkittävästi lyhentää resurssien etsimisen vasteaikaa.
32

Internet of Things zařízení s podporou ZigBee a 6LoWPAN / Internet of Things Device Based on ZigBee and 6LoWPAN

Halász, Dávid January 2016 (has links)
Internet of Things is the latest phenomenon in the computing industry. Even if it has not been completely defined yet, we are already surrounded by various devices connected to the Internet. This thesis project focuses on low cost and low-power wireless solutions and on the on-line backend behind the architecture. At the same time the present work also deals with Cloud Computing which can provide a highly scalable runtime environment for this backend without building an infrastructure. To handle the huge amount of data collected by billions of devices, BigData services could be used in the same cloud space. The project is a collection of the theoretical background of the Internet of Things; so as a result, it provides the reader with an overview of the concept. It also provides a walktrough of the design, implementation and testing process of a complex agricultural Internet of Things solution.
33

Internet of Things / Internet of Things

Piškula, David January 2019 (has links)
This thesis focuses on the Internet of Things and some of the most important problems it faces today. Among these are the overdependence on the Cloud and lack of autonomy, poor security and privacy, complicated initialization and power consumption. The work aims to implement a complex IoT solution that solves the discussed problems. The project is part of a collaboration with NXP Semicondutors and will be used to showcase the company's technologies.
34

Modular MiniTest Tester

Kallsäby, Mattias January 2017 (has links)
RealTest is a company located in V¨aster˚as, Sweden, that works with embedded systems and test systems. RealTest had a need for a new test system for one of their products, the MiniTester (MT) mk2 that is used to test Drive Control Units (DCUs) used on trains. The problems that had to be solved were, finding out the most common faults of the product, make the test system modifiable and scalable, have a software running on a Windows PC with a working GUI and test logic and design a hardware component measurement unit to generate and measure signals. The system described in this report is the software parts of the developed MiniTest tester that runs on a Windows PC as well as the hardware design. The programming of the measurement unit and the testing of that unit is not covered by this report. The hardware consist of custom PCBs and Arduino boards. The Windows PC programs implemented a GUI and test logic according to the goals with a few exceptions left for further work. These programs have been evaluated by emulating the hardware. The system is shown to be modifiable in practice by implementation and scalable in theory
35

Design and evaluation of a visual rapid prototyping environment in an existing smart home platform

Hamada, Skander January 2017 (has links)
Recent advances in the field of Internet of Things (IoT) are placing its own vision, as a platform of interconnected services and devices, at the heart of the smart home concept. This consolidation promises a new wave of innovative products designed in the open, and in which the user takes center stage starting from the very first steps. Therefore, researchers as well as product designers in these increasingly related fields are now tasked with a more complex mission when investigating user behavior. In this thesis we consider rapid prototyping as the upcoming standard process for investigating user interactions in the future smart home. Although past research contributed with several self-contained solutions (built from scratch) to allow such investigations, no accounts were found tackling the problem from our perspective, in which the focus is on how to enable rapid prototyping in an existing proprietary smart home platform by using open standards, software and hardware. To answer this question, we conducted our research with participation of academic researchers and professional designers in the context of an academic and industrial partnership, in an ongoing smart home research project. We used an approach based on the design science research process in combination with the user centered design (UCD) and agile software development methodologies. During this thesis we performed an end to end design process starting from ideation to implementation and evaluation; an architectural blueprint was proposed and a working prototype of our visual smart home rapid prototyping environment (SHRPE) was implemented and tested. The obtained results demonstrate the feasibility of enabling visual rapid prototyping capabilities in an existing smart home platform, by using the system integration process to introduce available open standards, software and hardware tools into the platform. In addition, evaluation results of user testing confirmed that using UCD to iteratively capture user needs in such complex context is a solid approach.

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