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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.
11

Metodologia para quantificação e acompanhamento de indicadores-chave de desempenho operacional

Giaquinto, Cláudia Daniela Melo January 2017 (has links)
Indicadores-chave de desempenho (KPIs) exercem um papel de extrema importância na indústria de processos, auxiliando na tomada de decisão. No entanto, para serem representativos precisam ser calculados de forma confiável. O presente trabalho propôs uma metodologia para o cálculo destes KPIs com base em técnicas de detecção do estado estacionário, remoção de ruído, propagação de erros e análise de sensibilidade. Estes KPIs foram apresentados, de acordo com o que consta na literatura, em uma nova ferramenta gráfica de acompanhamento proposta pelos autores, denominada StatSSCandlePlot. O StatSSCandlePlot apresenta os KPIs no padrão candlestick, que é bastante utilizado no mercado de ações, incluindo informações adicionais. O grande diferencial do StatSSCandlePlot é que os indicadores e suas respectivas propriedades exibidas são calculadas a partir de técnicas que englobam o tratamento de dados e análises estatísticas. A metodologia proposta foi aplicada em um estudo de caso de um chuveiro contendo dois princípios de aquecimento, gás e energia elétrica. Para este estudo, foi criado o Índice de Qualidade do Banho (IQB), que é um indicador dependente da temperatura e da vazão de saída, cujos dados foram avaliados em três cenários distintos, o primeiro quando o sistema é submetido a distúrbios na vazão, no segundo ocorre uma queda na temperatura da água fria e no último, o IQB foi avaliado quando o sistema foi submetido a distúrbios na vazão sob uma nova estratégia de controle da planta. A partir do StatSSCandlePlot, foi possível identificar as tendências do indicador nos diferentes cenários, a parcela de cada janela no estado estacionário, os valores a serem considerados do indicador e, de forma complementar, identificar a variável que mais influenciou na variação do indicador, através da análise de sensibilidade. / Key performance indicators (KPIs) play an extremely important role in the process industry, aiding in decision-making. However, to be representative they need to be calculated reliably. The present work proposed a methodology for the calculation of these KPIs based on steady state detection, noise removal, error propagation and sensitivity analysis techniques. These KPIs were presented, as far as it is known, in a new graphical KPIs monitoring tool proposed by the authors, called StatSSCandlePlot. StatSSCandlePlot introduces KPIs in the candlestick standard, which is widely used in the stock market, including additional information. The major difference of StatSSCandlePlot is that the indicators and their respective displayed properties are calculated from techniques that encompass data processing and statistical analysis. The proposed methodology was applied in a case study of a shower containing two principles of heating, gas and electric energy. For this study the Bath Quality Index (BQI) was created, which is a temperature and output flow dependent indicator, whose data were evaluated in three different scenarios, the first one when the system was submitted to flow disturbances, in the second one, a decrease in the temperature of the cold water and in the last one, the IQB was evaluated when the system was submitted to disturbances in the flow under a new strategy of control of the plant. From the StatSSCandlePlot, it was possible to identify the trends of the indicator in the different scenarios, the portion of each window in the steady state, the values to be considered in the indicator and, in a complementary way, to identify the variable that most influenced the variation of the indicator, through the sensitivity analysis.
12

One-dimensional Real-time Signal Denoising Using Wavelet-based Kalman Filtering

Durmaz, Murat 01 April 2007 (has links) (PDF)
Denoising signals is an important task of digital signal processing. Many linear and non-linear methods for signal denoising have been developed. Wavelet based denoising is the most famous nonlinear denoising method lately. In the linear case, Kalman filter is famous for its easy implementation and real-time nature. Wavelet- Kalman filter developed lately is an important improvement over Kalman filter, in which the Kalman filter operates in the wavelet domain, filtering the wavelet coeffi- cients, and resulting in the filtered wavelet transform of the signal in real-time. The real-time filtering and multiresolution representation is a powerful feature for many real world applications. This study explains in detail the derivation and implementation of Real-Time Wavelet-Kalman Filter method to remove noise from signals in real-time. The filter is enhanced to use different wavelet types than the Haar wavelet, and also it is improved to operate on higer block sizes than two. Wavelet shrinkage is integrated to the filter and it is shown that by utilizing this integration more noise suppression is obtainable. A user friendly application is developed to import, filter and export signals in Java programming language. And finally, the applicability of the proposed method to suppress noise from seismic waves coming from eartquakes and to enhance spontaneous potentials measured from groundwater wells is also shown.
13

Metodologia para quantificação e acompanhamento de indicadores-chave de desempenho operacional

Giaquinto, Cláudia Daniela Melo January 2017 (has links)
Indicadores-chave de desempenho (KPIs) exercem um papel de extrema importância na indústria de processos, auxiliando na tomada de decisão. No entanto, para serem representativos precisam ser calculados de forma confiável. O presente trabalho propôs uma metodologia para o cálculo destes KPIs com base em técnicas de detecção do estado estacionário, remoção de ruído, propagação de erros e análise de sensibilidade. Estes KPIs foram apresentados, de acordo com o que consta na literatura, em uma nova ferramenta gráfica de acompanhamento proposta pelos autores, denominada StatSSCandlePlot. O StatSSCandlePlot apresenta os KPIs no padrão candlestick, que é bastante utilizado no mercado de ações, incluindo informações adicionais. O grande diferencial do StatSSCandlePlot é que os indicadores e suas respectivas propriedades exibidas são calculadas a partir de técnicas que englobam o tratamento de dados e análises estatísticas. A metodologia proposta foi aplicada em um estudo de caso de um chuveiro contendo dois princípios de aquecimento, gás e energia elétrica. Para este estudo, foi criado o Índice de Qualidade do Banho (IQB), que é um indicador dependente da temperatura e da vazão de saída, cujos dados foram avaliados em três cenários distintos, o primeiro quando o sistema é submetido a distúrbios na vazão, no segundo ocorre uma queda na temperatura da água fria e no último, o IQB foi avaliado quando o sistema foi submetido a distúrbios na vazão sob uma nova estratégia de controle da planta. A partir do StatSSCandlePlot, foi possível identificar as tendências do indicador nos diferentes cenários, a parcela de cada janela no estado estacionário, os valores a serem considerados do indicador e, de forma complementar, identificar a variável que mais influenciou na variação do indicador, através da análise de sensibilidade. / Key performance indicators (KPIs) play an extremely important role in the process industry, aiding in decision-making. However, to be representative they need to be calculated reliably. The present work proposed a methodology for the calculation of these KPIs based on steady state detection, noise removal, error propagation and sensitivity analysis techniques. These KPIs were presented, as far as it is known, in a new graphical KPIs monitoring tool proposed by the authors, called StatSSCandlePlot. StatSSCandlePlot introduces KPIs in the candlestick standard, which is widely used in the stock market, including additional information. The major difference of StatSSCandlePlot is that the indicators and their respective displayed properties are calculated from techniques that encompass data processing and statistical analysis. The proposed methodology was applied in a case study of a shower containing two principles of heating, gas and electric energy. For this study the Bath Quality Index (BQI) was created, which is a temperature and output flow dependent indicator, whose data were evaluated in three different scenarios, the first one when the system was submitted to flow disturbances, in the second one, a decrease in the temperature of the cold water and in the last one, the IQB was evaluated when the system was submitted to disturbances in the flow under a new strategy of control of the plant. From the StatSSCandlePlot, it was possible to identify the trends of the indicator in the different scenarios, the portion of each window in the steady state, the values to be considered in the indicator and, in a complementary way, to identify the variable that most influenced the variation of the indicator, through the sensitivity analysis.
14

Eliminação de ruído impulsivo em imagens coloridas usando um filtro mediano seletivo e retoque digital /

Almeida, Marcos Proença de. January 2010 (has links)
Orientador: Maurílio Boaventura / Banca: Adilson Gonzaga / Banca: Eliana Xavier Linhares de Andrade / Resumo: Neste trabalho propõe-se um filtro mediano seletivo e um filtro híbrido para eliminação de ruído impulsivo em imagens digitais monocromáticas. O primeiro é baseado em uma modificação do filtro mediano por meio de um detector de ruído impulsivo. O segundo é obtido combinando-se o filtro mediano seletivo com um modelo de retoque digital. A remoção de ruído impulsivo em uma imagem colorida é realizada por meio da extensão dos filtros propostos para cada canal de cor da imagem. Os experimentos realizados indicam que os métodos propostos são eficazes na restauração de imagens com grandes densidades de ruído. / Abstract: In this paper a selective median filter and a hybrid filter for removing impulsive noise in digital grayscale images are proposed. The first is a median filter modification based on impulsive noise detector. The second is obtained by combining the selective median filter with a digital inpainting model. The noise removal in color image is obtained by extending the proposed filters for each color channel of the image. The experiments indicated that the proposed methods are powerful in restoring images with high densities noise. / Mestre
15

Metodologia para quantificação e acompanhamento de indicadores-chave de desempenho operacional

Giaquinto, Cláudia Daniela Melo January 2017 (has links)
Indicadores-chave de desempenho (KPIs) exercem um papel de extrema importância na indústria de processos, auxiliando na tomada de decisão. No entanto, para serem representativos precisam ser calculados de forma confiável. O presente trabalho propôs uma metodologia para o cálculo destes KPIs com base em técnicas de detecção do estado estacionário, remoção de ruído, propagação de erros e análise de sensibilidade. Estes KPIs foram apresentados, de acordo com o que consta na literatura, em uma nova ferramenta gráfica de acompanhamento proposta pelos autores, denominada StatSSCandlePlot. O StatSSCandlePlot apresenta os KPIs no padrão candlestick, que é bastante utilizado no mercado de ações, incluindo informações adicionais. O grande diferencial do StatSSCandlePlot é que os indicadores e suas respectivas propriedades exibidas são calculadas a partir de técnicas que englobam o tratamento de dados e análises estatísticas. A metodologia proposta foi aplicada em um estudo de caso de um chuveiro contendo dois princípios de aquecimento, gás e energia elétrica. Para este estudo, foi criado o Índice de Qualidade do Banho (IQB), que é um indicador dependente da temperatura e da vazão de saída, cujos dados foram avaliados em três cenários distintos, o primeiro quando o sistema é submetido a distúrbios na vazão, no segundo ocorre uma queda na temperatura da água fria e no último, o IQB foi avaliado quando o sistema foi submetido a distúrbios na vazão sob uma nova estratégia de controle da planta. A partir do StatSSCandlePlot, foi possível identificar as tendências do indicador nos diferentes cenários, a parcela de cada janela no estado estacionário, os valores a serem considerados do indicador e, de forma complementar, identificar a variável que mais influenciou na variação do indicador, através da análise de sensibilidade. / Key performance indicators (KPIs) play an extremely important role in the process industry, aiding in decision-making. However, to be representative they need to be calculated reliably. The present work proposed a methodology for the calculation of these KPIs based on steady state detection, noise removal, error propagation and sensitivity analysis techniques. These KPIs were presented, as far as it is known, in a new graphical KPIs monitoring tool proposed by the authors, called StatSSCandlePlot. StatSSCandlePlot introduces KPIs in the candlestick standard, which is widely used in the stock market, including additional information. The major difference of StatSSCandlePlot is that the indicators and their respective displayed properties are calculated from techniques that encompass data processing and statistical analysis. The proposed methodology was applied in a case study of a shower containing two principles of heating, gas and electric energy. For this study the Bath Quality Index (BQI) was created, which is a temperature and output flow dependent indicator, whose data were evaluated in three different scenarios, the first one when the system was submitted to flow disturbances, in the second one, a decrease in the temperature of the cold water and in the last one, the IQB was evaluated when the system was submitted to disturbances in the flow under a new strategy of control of the plant. From the StatSSCandlePlot, it was possible to identify the trends of the indicator in the different scenarios, the portion of each window in the steady state, the values to be considered in the indicator and, in a complementary way, to identify the variable that most influenced the variation of the indicator, through the sensitivity analysis.
16

雲端筆記之混合式文字切割與辨識 / Segmentation and recognition of mixed characters for cloud-based notes

王冠智, Wang, Guan Jhih Unknown Date (has links)
文字辨識為常見的電腦視覺應用之一,隨著正確率逐漸的上升,許多新的服務相繼出現,本論文改善了筆記管理軟體最主要的問題-文字切割,並提出兩種新的中文印刷體及手寫體的分類方法。我們將筆記文件中較常見的重點標記過濾後,再使用新核心的文字結構濾波取得筆記文件中的文字區塊,新的核心數據大幅降低原始核心的計算時間。本論文也使用文字結構濾波作為分辨印刷體、手寫體的特徵值,由於文字結構濾波會依據筆畫結構給予能量回饋,使得較工整的印刷體與手寫體能有所區別,此外也使用Sobel搭配不同角度範圍進行字體辨識,實驗結果證實了本論文所提出的文字切割及字體分類方法對於筆記文件資訊的處理是有效的。 / Character recognition is an important and practical application of computer vision. With the advance of this technology, more and more services embedding text recognition functionality have become available. However, segmentation is still the central issue in many situations. In this thesis, we tackle the character segmentation problem in note taking and management applications. We propose novel methods for the discrimination of handwritten and machine-printed Chinese characters. First, we perform noise removal using heuristics and apply a stroke filter with modified kernels to efficiently compute the bounding box for the text area. The responses of the stroke filter also serve as clues for differentiating machine-printed and handwritten texts. They are further enhanced using a SVM-based classifier that employs aggregated directional responses of edge detectors as input. Experiment results have validated the efficacy of the proposed approaches in terms of text localization and style recognition.
17

Received signal strength calibration for wireless local area network localization

Felix, Diego 11 August 2010 (has links)
Terminal localization for indoor Wireless Local Area Networks (WLAN) is critical for the deployment of location-aware computing inside of buildings. The purpose of this research work is not to develop a novel WLAN terminal location estimation technique or algorithm, but rather to tackle challenges in survey data collection and in calibration of multiple mobile terminal Received Signal Strength (RSS) data. Three major challenges are addressed in this thesis: first, to decrease the influence of outliers introduced in the distance measurements by Non-Line-of-Sight (NLoS) propagation when a ultrasonic sensor network is used for data collection; second, to obtain high localization accuracy in the presence of fluctuations of the RSS measurements caused by multipath fading; and third, to determine an automated calibration method to reduce large variations in RSS levels when different mobile devices need to be located. In this thesis, a robust window function is developed to mitigate the influence of outliers in survey terminal localization. Furthermore, spatial filtering of the RSS signals to reduce the effect of the distance-varying portion of noise is proposed. Two different survey point geometries are tested with the noise reduction technique: survey points arranged in sets of tight clusters and survey points uniformly distributed over the network area. Finally, an affine transformation is introduced as RSS calibration method between mobile devices to decrease the effect of RSS level variation and an automated calibration procedure based on the Expectation-Maximization (EM) algorithm is developed. The results show that the mean distance error in the survey terminal localization is well within an acceptable range for data collection. In addition, when the spatial averaging noise reduction filter is used the location accuracy improves by 16% and by 18% when the filter is applied to a clustered survey set as opposed to a straight-line survey set. Lastly, the location accuracy is within 2m when an affine function is used for RSS calibration and the automated calibration algorithm converged to the optimal transformation parameters after it was iterated for 11 locations.
18

Eliminação de ruído impulsivo em imagens coloridas usando um filtro mediano seletivo e retoque digital

Almeida, Marcos Proença de [UNESP] 26 February 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-26Bitstream added on 2014-06-13T19:47:27Z : No. of bitstreams: 1 almeida_mp_me_sjrp.pdf: 4937582 bytes, checksum: 4d9c67bc8dda1a2e1a742ee59be238fa (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Neste trabalho propõe-se um filtro mediano seletivo e um filtro híbrido para eliminação de ruído impulsivo em imagens digitais monocromáticas. O primeiro é baseado em uma modificação do filtro mediano por meio de um detector de ruído impulsivo. O segundo é obtido combinando-se o filtro mediano seletivo com um modelo de retoque digital. A remoção de ruído impulsivo em uma imagem colorida é realizada por meio da extensão dos filtros propostos para cada canal de cor da imagem. Os experimentos realizados indicam que os métodos propostos são eficazes na restauração de imagens com grandes densidades de ruído. / In this paper a selective median filter and a hybrid filter for removing impulsive noise in digital grayscale images are proposed. The first is a median filter modification based on impulsive noise detector. The second is obtained by combining the selective median filter with a digital inpainting model. The noise removal in color image is obtained by extending the proposed filters for each color channel of the image. The experiments indicated that the proposed methods are powerful in restoring images with high densities noise.
19

Noise-free distortion pedal for electric guitars : Designing and constructing a unique distortion pedal for live playing guitarists

Almqvist, Tobias, Nordberg, David January 2019 (has links)
Guitarists using effect pedals to alter the way their guitar sounds often face the problem of loud noise when they want their guitars to be completely silent. This can be the result of using a distortion pedal which works well when you’re playing, but not when you have a brief pause. This project focuses on developing a complete prototype of a distortion pedal that has an adjustable mute circuit, also known as a noise gate, built into it. The project pedal consists of some functions which commercially available effect pedals have; 6.3 mm input jack, on and off switch, both a battery connector and a DC-jack, and adjustable knobs for the different effects like drive, tone and volume. The distortion circuit is inspired by the BOSS SD1 SUPER OVERDRIVE pedal and the muting function is constructed with Junction Field Effect Transistors.Two prototypes were constructed; one with hole mounted components, and one with surface mounted components. They both work largely as imagined. When the guitar is played, the desired distorted sound can be heard and adjusted with a drive, tone and volume control. When the guitar is not played, all unwanted noise is completely muted. A sensitivity adjusting knob allows for different signal strengths to be muted.The chosen method for muting the signal introduces a short and faint unwanted noise during the muting process. While it would have been better to eliminate this noise too, the prototype introduces something new and helpful for guitarists using distortion pedals. With more work, this way of integrating a mute circuit in distortion pedals could potentially set a new standard. / Gitarrister som använder effektpedaler för att ändra hur deras gitarr låter stöter ofta på problemet där oönskat brus uppstår när de vill att gitarren ska vara helt tyst. Detta kan vara resultatet av att använda en distortionspedal som fungerar väl när man spelar på gitarren, men inte när man tar en kort paus. Detta projekt fokuserar på att utveckla en fulländad prototyp av en distortionspedal som har en justerbar mutefunktion, också kallad en brusgrind. Pedalen har några funktioner som vanligtvis finns hos de kommersiellt tillgängliga pedalerna; 6.3 mm ingångsoch utgångskontakter, av-/påknapp, strömförsörjning via både ett batteri och vägguttag, och justerbara kontroller för förvrängning, ton och volym. Distortionskretsen är inspirerad av pedalen BOSS SD1 SUPER OVERDRIVE och mute-funktionen använder sig av Junction Field Effect Transistorer.Två prototyper konstruerades; en med hålmonterade komponenter, och en med ytmonterade komponenter. De både prototyperna fungerar i stort sett enligt de uppsatta målen. När gitarren spelas så hörs det önskade förvrängda ljudet som kan justeras med kontrollerna. När gitarren inte spelas dämpas allt oönskat brus till en ohörbar nivå. En känslighetskontroll tillåter olika signalstyrkor att tystas.Den valda metoden för mute-funktionen introducerar ett kort och svagt oönskat ljud som uppstår under själva dämpningsprocessen. Medan detta oljud är något som bör lösas så ger prototypen fortfarande något unikt och hjälpsamt för gitarrister. Med mer arbete skulle detta kunna förbli en ny standard inom distortionspedaler.
20

Uma técnica multimalhas para eliminação de ruídos e retoque digita\" / An-edge preserving multigrid-like for image denoising and inpainting

Ferraz, Carolina Toledo 14 September 2006 (has links)
Técnicas baseadas na Equação de Fluxo Bem-Balanceada têm sido muitas vezes empregadas como eficientes ferramentas para eliminação de ruídos e preservação de arestas em imagens digitais. Embora efetivas, essas técnicas demandam alto custo computacional. Este trabalho objetiva propor uma técnica baseada na abordagem multigrid para acelerar a solução numérica da Equação de Fluxo Bem-Balanceada. A equação de difusão é resolvida em uma malha grossa e uma correção do erro na malha grossa para as mais finas é aplicada para gerar a solução desejada. A transferência entre malhas grossas e finas é feita pelo filtro de Mitchell, um esquema bem conhecido que é projetado para preservação de arestas. Além disso, a equação do transporte e a Equação do Fluxo de Curvatura são adaptadas à nossa técnica para retoque em imagens e eliminação de ruí?dos. Resultados numéricos são comparados quantitativamente e qualitativamente com outras abordagens, mostrando que o método aqui introduzido produz qualidade de imagens similares com muito menos tempo computacional. / Techniques based on the Well-Balanced Flow Equation have been employed as an efficient tool for edge preserving noise removal. Although effective, this technique demands high computational effort, rendering it not practical in several applications. This work aims at proposing a multigrid-like technique for speeding up the solution of the Well- Balanced Flow equation. In fact, the diffusion equation is solved in a coarse grid and a coarse-to-fine error correction is applied in order to generate the desired solution. The transfer between coarser and finer grids is made by the Mitchell-Filter, a well known interpolation scheme that is designed for preserving edges. Furthermore, the solution of the transport and the Mean Curvature Flow equations is adapted to the multigrid like technique for image inpainting and denoising. Numerical results are compared quantitative and qualitatively with other approaches, showing that our method produces similar image quality with much lower computational time.

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