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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

Nástroj pro modelování a simulaci technologických procesů / Tool for Modelling and Simulation of Technologic Processes

Skydánek, Libor January 2009 (has links)
This thesis focuses on the problem of technological process modelling and simulation. It is based on the realistic requirements of the Faculty of Mechanical Engineering, where they lacked an extensible and open simulation tool with the ability to model biomass processing. In this work we explain the main concepts in the field of (physical) chemistry, the systematic approach to process modelling and simulation and we discuss various problems of simulation methods. We also describe the differences between simulation and design specifications and give reasons for choosing the sequential modular approach. An important part of the work is aimed at the design of the simulation tool's architecture, where the main emphasis is laid on the extensibility of future application. The tool has been implemented and it is now sucessfully being used at the Faculty of Mechanical Engineering.
32

Study cases of energy, microclimate and aeraulic simulations at district scale:  engineering and management frameworks for smarter urban development

Pinol, Thomas January 2017 (has links)
With population growth and climate change issues, cities will face social, economic and environmental challenges. They are accountable for most of the energy consumption and GHG emissions, and the building sector represents roughly 40% of the final energy consumption worldwide. Still, cities transform by renewing or creating districts, which design comes with specific engineering and management methods. Simulations tools at district scale might lead to more sustainable urban development by considering phenomena at such scale. Energy, microclimate and aeraulic simulations are performed on two study cases from real estate projects in France. This thesis investigates whether the tools allow to unlock new development strategies, and which engineering and management frameworks they require. The benefits for urban planners and architects are discussed, and the replicability of the tools is assessed. The studies also provide academic knowledge, beneficial to the actors for qualitative analyses. The energy needs and potential of energy sharing are assessed. Sensitivity analyses on design characteristics such as windows or insulation provide insight on their respective impacts on energy needs and sharing. The microclimate and heat island effects in the district are investigated, thanks to the evolution of air temperature and comfort index PET, bringing knowledge on the effects of trees and buildings. The winds within several urban plans are also simulated, providing insight on comfort in the district as well as academic experience on the relations between architecture and winds. Those studies therefore provide assessment and recommendations for the district, as well as knowledge for future qualitative and quantitative analyses. Plus, modeling and management issues and their resolutions help to construct a framework to improve the efficiency of such studies in terms of time, and therefore cost. Eventually, a simplified aeraulic study tests the engineering and management frameworks. Finally, conclusions present the design strategies and the management requirements to replicate such studies. / Med befolkningstillväxt och klimatfrågor kommer städerna att möta sociala, ekonomiska och miljömässiga utmaningar. De är ansvariga för de flesta av energiförbrukningen och växthusgasutsläppen, och byggsektorn utgör ungefär 40% av den slutliga energiförbrukningen. Ändå, transformerar städerna genom att förnya eller skapa distrikt, vilken design kommer med specifika ingenjörsmetoder och hanteringsmetoder. Simuleringsverktyg i distriktskalan kan leda till en mer hållbar stadsutveckling genom att överväga fenomen i sådan skala. Energi, mikroklimat och aerauliska simuleringar utförs på två studiefall från fastighetsprojekt i Frankrike. Denna maggisteruppsats undersöker om verktygen tillåter att låsa upp nya utvecklingsstrategier, och vilka tekniska och ledande ramar de behöver. Fördelarna för stadsplanerare och arkitekter diskuteras, och verktygets replikerbarhet bedöms. Studierna ger också akademisk kunskap som är till nytta för aktörerna för kvalitativa analyser. Energianvändningen och potentialen för energidelning utvärderas. Känslighetsanalyser på designegenskaper som fönster eller isolering ger insikt om deras respektive inverkan på energibehov och delning. Mikroklimat och ”värme ö effekter” i distriktet undersöks tack vare utvecklingen av lufttemperaturen och komfortindex PET, vilket ger kunskap om effekterna av träd och byggnader. Vindarna inom flera stadsplaner simuleras också, vilket ger insikt om komfort i distriktet samt akademisk erfarenhet av relationerna mellan arkitektur och vindar. Dessa studier ger därför bedömning och rekommendationer för distriktet, samt kunskaper om framtida kvalitativa och kvantitativa analyser. Dessutom, modellerings- och hanteringsfrågor och deras resolutioner bidrar till att konstruera en ram för att förbättra effektiviteten av sådana studier i form av tid och därmed kosta. Så småningom tester en förenklad aeraulisk studie av konstruktions- och förvaltningsramarna. Slutligen presenterar slutsatserna designstrategierna och förvaltningskraven för att replikera sådana studier.
33

Design and Development of a Passive Infra-Red-Based Sensor Platform for Outdoor Deployment

Upadrashta, Raviteja January 2017 (has links) (PDF)
This thesis presents the development of a Sensor Tower Platform (STP) comprised of an array of Passive Infra-Red (PIR) sensors along with a classification algorithm that enables the STP to distinguish between human intrusion, animal intrusion and clutter arising from wind-blown vegetative movement in an outdoor environment. The research was motivated by the aim of exploring the potential use of wireless sensor networks (WSNs) as an early-warning system to help mitigate human-wildlife conflicts occurring at the edge of a forest. While PIR sensors are in commonplace use in indoor settings, their use in an outdoor environment is hampered by the fact that they are prone to false alarms arising from wind-blown vegetation. Every PIR sensor is made up of one or more pairs of pyroelectric pixels arranged in a plane, and the orientation of interest in this thesis is one in which this plane is a vertical plane, i.e., a plane perpendicular to the ground plane. The intersection of the Field Of View (FOV) of the PIR sensor with a second vertical plane that lies within the FOV of the PIR sensor, is called the virtual pixel array (VPA). The structure of the VPA corresponding to the plane along which intruder motion takes place determines the form of the signal generated by the PIR sensor. The STP developed in this thesis employs an array of PIR sensors designed so as to result in a VPA that makes it easier to discriminate between human and animal intrusion while keeping to a small level false alarms arising from vegetative motion. The design was carried out in iterative fashion, with each successive iteration separated by a lengthy testing phase. There were a total of 5 design iterations spanning a total period of 14 months. Given the inherent challenges involved in gathering data corresponding to animal intrusion, the testing of the SP was carried out both using real-world data and through simulation. Simulation was carried out by developing a tool that employed animation software to simulate intruder and animal motion as well as some limited models of wind-blown vegetation. More specifically, the simulation tool employed 3-dimensional models of intruder and shrub motion that were developed using the popular animation software Blender. The simulated output signal of the PIR sensor was then generated by calculating the area of the 3-dimensional intruder when projected onto the VPA of the STP. An algorithm for efficiently calculating this to a good degree of approximation was implemented in Open Graphics Library (OpenGL). The simulation tool was useful both for evaluating various competing design alternatives as well as for developing an intuition for the kind of signals the SP would generate without the need for time-consuming and challenging animal-motion data collection. Real-world data corresponding to human motion was gathered on the campus of the Indian Institute of Science (IISc), while animal data was recorded at a dog-trainer facility in Kengeri as well as the Bannerghatta Biological Park, both located in the outskirts of Bengaluru. The array of PIR sensors was designed so as to result in a VPA that had good spatial resolution. The spatial resolution capabilities of the STP permitted distinguishing between human and animal motion with good accuracy based on low-complexity, signal-energy computations. Rejecting false alarms arising from vegetative movement proved to be more challenging. While the inherent spatial resolution of the STP was very helpful, an alternative approach turned out to have much higher accuracy, although it is computationally more intensive. Under this approach, the intruder signal, either human or animal, was modelled as a chirp waveform. When the intruder moves along a circular arc surrounding the STP, the resulting signal is periodic with constant frequency. However, when the intruder moves along a more likely straight-line path, the resultant signal has a strong chirp component. Clutter signals arising from vegetative motion does not exhibit this chirp behavior and an algorithm that exploited this difference turned in a classification accuracy in excess of 97%.
34

Modifikace struktury křemíkových solárních článků / Modification of silicon solar cells structure

Strachala, Dávid January 2014 (has links)
The aim of the work is to create a coherent overview of the silicon monocrystaline solar cell in terms of the physical principle of the structure and sequence of technological operations necessary for its production. The effect of individual manufacturing steps is discussed in relation to the requirement of decreasing recombination, optical and ohmic losses of the monocrystalline solar cell. Due to a theoretical assumption, one-dimensional model of solar cell was created in a PC1D software that was later optimized to achieve the highest possible efficiency. Using the available technologies, final model of the solar cell is manufactured in Solartec company and in the end of the work compared with the output of simulation.
35

[en] SIMULATION AND PERFORMANCE OF INTEGRATED DATA AND SPEECH SERVICE IN CELULAR SISTEMS USING GSM/HSCSD / [pt] SIMULAÇÃO E DESEMPENHO DE SERVIÇO INTEGRADO DE VOZ E DADOS EM SISTEMAS CELULARES UTILIZANDO O PADRÃO GSM/HSCSD

TALLES ALEXANDRE CAMILO 16 May 2003 (has links)
[pt] Com o crescimento da utilização das redes celulares para a transmissão de dados, as operadoras de telefonia móvel estão enfrentando um aumento dramático na utilização do recurso rádio para suprir esta nova necessidade. Com isto, estão sendo obrigadas a migrarem para novas tecnologias que propiciem uma alta eficiência espectral, permitindo assim uma melhor utilização do espectro disponível. Este trabalho descreve uma ferramenta de simulação desenvolvida para analisar o gerenciamento dos recursos de rádio, além de propor um novo algoritmo de alocação de canais de dados para sistemas móveis pessoais, permitindo a transmissão de voz e dados sobre a mesma interface aérea. É sabido que é extremamente difícil levar em conta todos os parâmetros que devem ser considerados em um sistema móvel real. Procurou-se então adotar os mais conhecidos modelos de propagação, de mobilidade e de tráfego de voz e de dados disponíveis na literatura, de forma a tentar aproximar a ferramenta de simulação o máximo possível do caso real. A contribuição deste trabalho é oferecer uma ferramenta de simulação para as redes GSM/HSCSD que permita a otimização da eficiência no uso do espectro disponível para transmissão. Esta ferramenta possibilita ao usuário, além de analisar a capacidade do sistema, o controle de potência e estratégias de handover, avaliar novos algoritmos de alocação de canal para o tráfego de voz e dados em conjunto. Ao final desta dissertação serão apresentados os resultados obtidos com a utilização de um novo algoritmo de alocação de canais para o tráfego de dados, além de realizar algumas outras simulações buscando maximizar a eficiência espectral do sistema utilizando deste novo algoritmo. / [en] Due to the increasing use of cellular networks for data transmission, mobile telephone operators are facing a dramatic raise in using radio resources to supply their demand. As a result, they are being forced to migrate to new technologies that provide high spectral efficiency, allowing an optimized use of available spectrum. This work describes the development of an advanced tool to analyze the operator management of radio transmission for personal mobile systems. The model was built considering well-known propagation, mobility, voice and data traffic for transmission assumptions, in order to approximate the developed tool to the real world mobile systems. The simulation tool is suited for GSM/HSCSD networks allowing engineers to optimize the efficient use of the available spectrum. It also permits the evaluation of system capacity as well as the analysis of power control and handover strategies. Another application exploited in this work is the investigation of resource allocation algorithms. A new algorithm for resource allocation in integrated voice and data environments was proposed and its performance was evaluated using the simulation tool.

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