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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

Tamanho ideal de parcelas para avaliação da intensidade de infestação por broca da cana-de-açúcar /

Suzuki, Aline Namie. January 2018 (has links)
Orientador: Glaucia Amorim Faria / Resumo: Considerando que a intensidade de infestação (I.I.%) é um importante dado sobre o dano causado pela Diatraea saccharalis em cana-de-açúcar e que existem poucos trabalhos na literatura relacionados ao tamanho de ótimo de parcela para este tipo de amostragem, o objetivo deste trabalho foi estimar o tamanho ótimo de parcela em hectares e número de colmos que deverá ser utilizado no processo de amostragem de modo que represente a intensidade de infestação causada pelo ataque da D. saccharalis em cana-de-açúcar. Para os cálculos relativos ao tamanho da área a ser amostrada foram utilizados quatro métodos para o cálculo do tamanho de parcela: método de inspeção visual da curvatura máxima, método da máxima curvatura modificado, modelo linear segmentado com platô e modelo quadrático segmentado com platô. Para os cálculos referentes ao número de entrenós foi utilizado o método da estimativa da suficiência amostral. O método da máxima curvatura modificado foi o que proporcionou melhores resultados. De acordo com os resultados encontrados neste trabalho, podemos concluir que o número mínimo a ser amostrado é o de 36 entrenós por hectare e a área máxima a ser amostrada é a de 27,5 hectares. / Abstract: Infestation intensity (II%) is an important data on the damage caused by Diatraea saccharalis in sugarcane. There are few studies in the literature related to the optimal plot size for this type of sampling. The objective of this work is to estimate the optimal plot size in hectares and number of stems to be used in the sampling process to represent the intensity of infestation caused by D. saccharalis attack on sugarcane. For the calculation of the size of the minimum sampled area, four methods were used: 1. visual inspection method of maximum curvature; 2. modified maximum curvature method; 3. segmented linear model with plateau and; 4. quadratic segmented model with plateau. For the calculations referring to the number of internodes, the method of estimating the sample adequacy was used. The modified maximum curvature method presented the best results. According this study, the minimum number to be sampled is 36 trains per hectare and the maximum area to be sampled is 27.5 hectares. / Mestre
42

Contraintes et opportunités pour l'automatisation de l'inspection visuelle au regard du processus humain / Constraints and opportunities for automation of visual inspection with regard to the human process

Désage, Simon-Frédéric 24 November 2015 (has links)
Ces travaux de recherche ont pour ambition de contribuer à l'automatisation de l'inspection visuelle, dans le cadre du contrôle qualité de pièces métalliques à géométrie complexe. En soi, de nombreuses techniques d'optique, de numérisation, d'implémentation de rendu photo-réaliste, de classification d'images ou de données, et de reconnaissance de formes sont déjà fortement développées et appliquées chacune dans des domaines particuliers. Or, elles ne sont pas, ou rarement pour des cas particuliers, combinées pour obtenir une méthode complète de numérisation de l'apparence jusqu'à la reconnaissance, effective et perceptuelle, de l'objet et des anomalies esthétiques.Ces travaux ont profité des avancements des thèses précédentes sur la formalisation du contrôle qualité ainsi que sur un système agile de numérisation d'aspect de surface permettant la mise en évidence de toute la diversité d'anomalies esthétiques de surfaces. Ainsi, la contribution majeure réside dans l'adaptation des méthodes de traitement d'images à la structure formalisée du contrôle qualité, au format riche des données d'apparence et aux méthodes de classification pour réaliser la reconnaissance telle que le contrôleur humain.En ce sens, la thèse propose un décryptage des différentes méthodologies liées au contrôle qualité, au comportement du contrôleur humain, aux anomalies d'aspect de surface, aux managements et traitements de l'information visuelle, jusqu'à la combinaison de toutes ces contraintes pour obtenir un système de substitution partielle au contrôleur humain. L'objectif de la thèse, et du décryptage, est d'identifier et de réduire les sources de variabilité pour obtenir un meilleur contrôle qualité, notamment par l'automatisation intelligente et structurée de l'inspection visuelle. A partir d'un dispositif de vision par ordinateur choisi, la solution proposée consiste à analyser la texture visuelle. Celle est considérée en tant que signature globale de l'information d'apparence visuelle supérieure à une unique image contenant des textures images. L'analyse est effectuée avec des mécanismes de reconnaissance de formes et d'apprentissage machine pour établir la détection et l'évaluation automatiques d'anomalies d'aspect. / This research has the ambition to contribute to the automation of visual inspection, in the quality control of complex geometry metal parts. Firstly, many optical techniques, scanning, implementation of photorealistic rendering, classification of images or data, and pattern recognition are already highly developed and applied in each particular areas. But they are not, or rarely, in special cases, combined for a complete scanning method of appearance to the recognition, effective and perceptual, of object and aesthetic anomalies.This work benefited from the advancements of previous thesis on the formalization of quality control, as well as an agile system of surface appearance scanning to highlight the diversity of aesthetic anomalies surfaces. Thus, the major contribution lies in the adaptation of image processing methods to the formal structure of quality control, rich appearance data format and classification methods to achieve recognition as the human controller.In this sense, the thesis deciphers the different methodologies related to quality control, the human controller processes, surface appearance defects, the managements and processing of visual information, to the combination of all these constraints for a partial substitution system of the human controller. The aim of the thesis is to identify and reduce sources of variability to obtain better quality control, including through the intelligent and structured automation of visual inspection. From a selected computer vision device, the proposed solution is to analyze visual texture. This is regarded as a global signature of superior visual appearance information to a single image containing images textures. The analysis is performed with pattern recognition and machine learning mechanisms to develop automatic detection and evaluation of appearance defects.
43

A retrospective study of utilisation and uptake of visual inspection with acetic acid (VIA) as a cervical cancer screening method at a specific hospital in Zimbabwe

Thistle, Pedrinah 08 1900 (has links)
The purpose of this study was to describe the factors that determine the utilisation of VIA, and to investigate the socio-economic status of women who undergone VIA. A retrospective document analysis of 323 clinical records was conducted at a specific rural hospital in Zimbabwe. A retrospective, cross-sectional, non-experimental, descriptive, analysis of clinical records was conducted using a checklist to extract data from the records of women who have undergone VIA for cervical screening at the specific rural hospital. The results revealed that 70% (N=225) were from outside the catchment area, 73% (N=234) were poor, 54% (N=173) were of high parity, 85% (N=275) were ill with conditions that included lower back and abdominal pains, excessive vaginal discharge and vaginal bleeding after intercourse. The study further revealed that 72% (N=226) had no prior cervical cancer screening and 87% (N=277) were screened by chance. The conclusion drawn was that socio-economic and logistical constraints hinder cervical cancer screening among rural women. It is recommended that VIA screening and health education on cervical cancer be offered to all women visiting healthcare facilities. Furthermore, the government should consider funding in order to prioritise women’s health issues. / Health Studies / M.A. (Nursing Science)
44

Poruchy mostních vozovek a jejich příčiny / Defects of bridge pavement and cause of defects

Kubová, Simona January 2014 (has links)
As part of my master's thesis I have conducted a visual inspection and record failures of bridge roadway at selected highway bridges, roads D47, D3 and D8 and photographic documentation, which is included in Annex. Also I have based on their speeches and documents the results of control tests determine their causes and to propose appropriate repair or maintenance.
45

Um estudo das condi??es de percola??o e estabilidade em barragens de terra mediante m?todos geof?sicos: caso do dique de Sant Lloren? de Montgai - Espanha

Teixeira, Washington Luiz Evangelista 17 June 2013 (has links)
Made available in DSpace on 2015-02-24T19:48:45Z (GMT). No. of bitstreams: 1 WashingtonLET_TESE.pdf: 9876489 bytes, checksum: b0b53c16cdf88ab9e63cb1b22c08ab0f (MD5) Previous issue date: 2013-06-17 / The monitoring of Earth dam makes use of visual inspection and instrumentation to identify and characterize the deterioration that compromises the security of earth dams and associated structures. The visual inspection is subjective and can lead to misinterpretation or omission of important information and, some problems are detected too late. The instrumentation are efficient but certain technical or operational issues can cause restrictions. Thereby, visual inspections and instrumentation can lead to a lack of information. Geophysics offers consolidated, low-cost methods that are non-invasive, non-destructive and low cost. They have a strong potential and can be used assisting instrumentation. In the case that a visual inspection and strumentation does not provide all the necessary information, geophysical methods would provide more complete and relevant information. In order to test these theories, geophysical acquisitions were performed using Georadar (GPR), Electric resistivity, Seismic refraction, and Refraction Microtremor (ReMi) on the dike of the dam in Sant Lloren? de Montgai, located in the province of Lleida, 145 km from Barcelona, Catalonia. The results confirmed that the geophysical methods used each responded satisfactorily to the conditions of the earth dike, the anomalies present and the geological features found, such as alluvium and carbonate and evaporite rocks. It has also been confirmed that these methods, when used in an integrated manner, are able to reduce the ambiguities in individual interpretations. They facilitate improved imaging of the interior dikes and of major geological features, thus inspecting the massif and its foundation. Consequently, the results obtained in this study demonstrated that these geophysical methods are sufficiently effective for inspecting earth dams and they are an important tool in the instrumentation and visual inspection of the security of the dams / O monitoramento do comportamento de barragens de terra faz uso da inspe??o visual e da instrumenta??o para identificar e caracterizar danos no barramento ou estruturas auxiliares. A primeira ? subjetiva possibilitando erros de interpreta??o ou omiss?o, mesmo assim, alguns problemas s? podem ser detectados tardiamente. A instrumenta??o tem se mostrado satisfat?ria, mas pode apresentar restri??es por quest?es t?cnicas ou operacionais. Assim, pode existir defici?ncia nas informa??es produzidas pela inspe??o visual e pela instrumenta??o. A Geof?sica disp?e de m?todos consolidados, n?o invasivos, n?o destrutivos, e de baixo custo, com forte potencial para atuar auxiliando a instrumenta??o convencional, podendo, no caso de inexist?ncia ou falha geral desta, fornecer informa??es mais completas e relevantes que a inspe??o visual. Para fundamentar essas afirma??es, foram realizadas aquisi??es geof?sicas de Resistividade El?trica, Georadar (GPR), S?smica de refra??o, e Refraction Microtremor (ReMi) no dique da barragem de Sant Lloren? de Montgai, localizada na prov?ncia de Lleida, a 145 Km de Barcelona Catalunha. Os resultados obtidos confirmaram que os m?todos geof?sicos utilizados respondem individualmente de forma satisfat?ria ?s condi??es construtivas do dique de terra, ?s anomalias presentes, e ? geologia encontrada (aluvi?o, rochas carbon?ticas e evapor?ticas). Pode se afirmar ainda que esses m?todos, quando utilizados de forma integrada, s?o capazes de diminuir as ambiguidades nas interpreta??es individuais e permitem o imageamento satisfat?rio do interior do dique e das principais fei??es geol?gicas e dessa forma inspecionar o maci?o e sua funda??o. Dessa forma, os resultados apresentados por essa pesquisa demonstram que os m?todos geof?sicos constituem uma importante ferramenta que pode ser utilizada na verifica??o das condi??es do maci?o de uma barragem de terra
46

Evaluation and Structural Behavior of Deteriorated Precast, Prestressed Concrete Box Beams

Ryan T Whelchel (7874897) 22 November 2019 (has links)
Adjacent precast, prestressed box beam bridges have a history of poor performance and have been observed to exhibit common types of deterioration including longitudinal cracking, concrete spalling, and deterioration of the concrete top flange. The nature of these types of deterioration leads to uncertainty of the extent and effect of deterioration on structural behavior. Due to limitations in previous research and understanding of the strength of deteriorated box beam bridges, conservative assumptions are being made for the assessment and load rating of these bridges. Furthermore, the design of new box beam bridges, which can offer an efficient and economical solution, is often discouraged due to poor past performance. Therefore, the objective of this research is to develop improved recommendations for the inspection, load rating, and design of adjacent box beam bridges. Through a series of bridge inspections, deteriorated box beams were identified and acquired for experimental testing. The extent of corrosion was determined through visual inspection, non-destructive evaluation, and destructive evaluation. Non-destructive tests (NDT) included the use of connectionless electrical pulse response analysis (CEPRA), ground penetrating radar (GPR), and half-cell potentials. The deteriorated capacity was determined through structural testing, and an analysis procedure was developed to estimate deteriorated behavior. A rehabilitation procedure was also developed to restore load transfer of adjacent beams in cases where shear key failures are suspected. Based on the understanding of deterioration developed through study of deteriorated adjacent box beam bridges, improved inspection and load rating procedure are provided along with design recommendations for the next generation of box beam bridges.
47

Dlouhodobé posuzování vozovek opravených recyklací podkladů / Pavement Long-term Evaluation with Recycled Base Course

Kadlubiec, Janusz January 2012 (has links)
My work deals with monitoring communications sections, which were renovated zrecyklováním existing surface. I documented these communications and to assess their condition after the time of use. Subscribed sections I put into the database PMS.
48

Video extraction for fast content access to MPEG compressed videos

Jiang, Jianmin, Weng, Y. 09 June 2009 (has links)
No / As existing video processing technology is primarily developed in the pixel domain yet digital video is stored in compressed format, any application of those techniques to compressed videos would require decompression. For discrete cosine transform (DCT)-based MPEG compressed videos, the computing cost of standard row-by-row and column-by-column inverse DCT (IDCT) transforms for a block of 8 8 elements requires 4096 multiplications and 4032 additions, although practical implementation only requires 1024 multiplications and 896 additions. In this paper, we propose a new algorithm to extract videos directly from MPEG compressed domain (DCT domain) without full IDCT, which is described in three extraction schemes: 1) video extraction in 2 2 blocks with four coefficients; 2) video extraction in 4 4 blocks with four DCT coefficients; and 3) video extraction in 4 4 blocks with nine DCT coefficients. The computing cost incurred only requires 8 additions and no multiplication for the first scheme, 2 multiplication and 28 additions for the second scheme, and 47 additions (no multiplication) for the third scheme. Extensive experiments were carried out, and the results reveal that: 1) the extracted video maintains competitive quality in terms of visual perception and inspection and 2) the extracted videos preserve the content well in comparison with those fully decompressed ones in terms of histogram measurement. As a result, the proposed algorithm will provide useful tools in bridging the gap between pixel domain and compressed domain to facilitate content analysis with low latency and high efficiency such as those applications in surveillance videos, interactive multimedia, and image processing.
49

An Unmanned Aerial Systems Evaluation Chamber for Bridge Inspection

Jose Capa Salinas (11178285) 26 July 2021 (has links)
<p>Civil engineering structures must provide an adequate and safe performance during their time of service, and the owners of these structures must have a reliable inspection strategy to ensure time-dependent damage does not become excessive. Visual inspection is the first step in every structural inspection; however, many elements in the majority of structures are difficult to access and require specialized personal and equipment. In an attempt to reduce the risk of the inspector and the cost of additional equipment, the use of Unmanned Aircraft Systems (UAS) has been increasing in the last years. The absence of standards and regulations regarding the use of UAS in inspection of structures has allowed the market to widely advertise Unmanned Aerial Vehicles (UAV) without protocols or qualifications that prove their effectiveness, leaving the owners of the structures to solely rely on claims of the vendors before deciding which technology suits their particular inspection needs. Focusing primarily on bridge inspection, this research aimed to address the lack of performance-based evaluation and standards for UAS, developing a validation criterion to evaluate a given UAS based on a repeatable test that resembles typical conditions in a structure. </p><p><br></p><p>Current applications of UAS in inspection of structures along with its advantages and limitations were studied to determine the current status of UAS technologies. A maximum typical rotor-tip-to-rotor-tip distance of an UAV was determined based on typical UAVs used in bridge inspection, and two main parameters were found to be relevant when flying close to structures: proximity effects in the UAV and availability of visual line of sight. Distances where proximity effects are relevant were determined based on several field inspections and flights close to structures. In addition, the use of supplementary technologies such as Global Positioning System (GPS) and Inertial Measurement Units (IMU) was studied to understand their effect during inspection. </p><p><br></p><p>Following the analysis, the author introduces the idea of a series of obstacles and elements inside an enclosed space that resemble components of bridge structures to be inspected using UAVs, allowing repeatability of the test by controlling outside parameters such as lighting condition, wind, precipitation, temperature, and GPS signal. Using distances based on proximity effects, maximum typical rotor-tip-to-rotor-tip distance, and a gallery of bridges and situations when flying close to bridge structures, a final arrangement of elements is presented as the evaluation chamber. Components inside the evaluation chamber include both “real” steel and concrete specimens as well as those intended to simulate various geometric configurations on which other features are mounted. Pictures of damages of steel and concrete elements have been placed in the internal faces of the obstacles that can be assessed either in real-time flight or in post-processing work. A detailed comparison between the objectives of this research project and the results obtained by the evaluation chamber was performed using visual evaluation and resolution charts for the images obtained, the availability of visual line of sight during the test, and the absence of GPS signal.</p><p><br></p><p>From the comparison and analysis conducted and based on satisfactory flight results as images obtained during flights, the evaluation chamber is concluded to be a repeatable and reliable tool to apply to any UAS prior to inspect bridges and other structures, and the author recommends to refrain from conducting an inspection if the UAS does not comply with the minimum requirements presented in this research work. Additionally, this research provided a clearer understanding of the general phenomenon presented when UAVs approach structures and attempts to fill the gap of knowledge regarding minimum requirements and criterion for the use of UAS technologies in inspection of structures.</p>

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