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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.
1

Gas turbine engine health monitoring by fault pattern matching method

Lee, Y. H. January 1998 (has links)
The gas turbine engine has a wide range of applications, these include industrial and aerospace applications on locomotive, ferry, compressor and power generation, and the most popular application will be for the air transportation. The application for air transportation including military and commercial aircraft is highly sensitive to safety concerns. The engine health monitoring system plays a major role for addressing this concern, a good engine monitoring system will not only to provide immediate and correct information to the engine user but also provide useful information for managing the maintenance activities. Without a reliable performance diagnosis module involved, there will be not possible to build a good health monitoring system. There are many methodologies had been proposed and studied during past three decades, and yet still struggling to search for some good techniques to handle instrumentation errors. In order to develop a reliable engine performance diagnosis technique, a fully understanding and proper handling of the instrumentation is essential. A engine performance fault pattern matching method has been proposed and developed in this study, two fault libraries contains a complete defined set of 51963 faults was created by using a newly serviced fighter engine component data. This pattern matching system had been verified by different approaches, such as compares with linear and nonlinear diagnosis results and compares with performance sensitivity analysis results by using LTF program engine data. The outcomes from the verications indicate an encouraging result for further exploring this method. In conclusion, this research has not only propose a feasible performance diagnosis techniques, but also developed and verified through different kind of approaches for this techniques. In addition to that, by proper manipulating the created fault library, a possible new tool for analyzing the application of instruments' implementation was discovered. The author believes there will be more to study by using this created fault pattern library. For instance, this fault pattern library can be treated as a very good initial training sets for neural networking to develop a neural diagnosis technique. This study has put a new milestone for further exploring gas turbine diagnosis technique by using fault pattern related methods.
2

Sistema remoto para análise automática de ECGs nos padrões HL7 AECG e DICOM-ECG

Lima, Marcelo Araújo January 2017 (has links)
LIMA, M. A. Sistema remoto para análise automática de ECGs nos padrões HL7 AECG e DICOM-ECG. 2017. 78 f. Dissertação (Mestrado em Engenharia de Teleinformática)–Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2017. / Submitted by Marlene Sousa (mmarlene@ufc.br) on 2017-09-25T17:22:14Z No. of bitstreams: 1 2017_dis_malima.pdf: 1997199 bytes, checksum: 6819aa354bd4c431de68f3bd5aca3b39 (MD5) / Approved for entry into archive by Marlene Sousa (mmarlene@ufc.br) on 2017-09-25T17:23:17Z (GMT) No. of bitstreams: 1 2017_dis_malima.pdf: 1997199 bytes, checksum: 6819aa354bd4c431de68f3bd5aca3b39 (MD5) / Made available in DSpace on 2017-09-25T17:23:17Z (GMT). No. of bitstreams: 1 2017_dis_malima.pdf: 1997199 bytes, checksum: 6819aa354bd4c431de68f3bd5aca3b39 (MD5) Previous issue date: 2017 / According to the World Health Organization, about 17.5 million people die each year from cardiovascular disease. The early diagnosis and treatment is crucial to reduce this high number of deaths from cardiovascular diseases. Due to the importance of the electrocardiogram (ECG) analysis, which represents one of the main tests for the detection of these cardiovascular diseases, in the present dissertation is proposed a remote system for automatic ECGs analysis based on webservices that can substantially assist the doctor, using the extracted ECGs information, with the purpose to generate reports. Hence, a Middleware is proposed to abstract the complexities and to facilitate the construction of tools that allow the ECGs automatic analysis. The proposed architecture consists on a server which provides the computational algorithms to identify the main waves present in ECGs such as QRS complex, P and T waves, and support the open standards of HL7 aECG and DICOM-ECG. In order to validate the proposed Middleware and contribute to the medical community, especially the Walter Cantídio University Hospital, a Web application for remotely accessible ECG report was developed. The proposed solution was tested using the database MITDB to simulate the patients of the system and produce the results presented in this dissertation. The proposed solution met the established requirements which makes the proposed solution viable financially and technically. / De acordo com a Organização Mundial da Saúde (OMS), cerca de 17,5 milhões de pessoas morrem todos os anos vítimas de doenças cardiovasculares. O diagnóstico e tratamento precoce às pessoas com doenças cardiovasculares é fundamental para reduzir este número elevado de óbitos. Devido à importância da análise de Eletrocardiograma (ECG), que representa um dos principais exames para detecção destas doenças cardiovasculares, na presente dissertação é proposto um sistema remoto para análise automática de Eletrocardiograma (ECG)s baseado em Web services que pode auxiliar substancialmente o médico especialista, a partir de informações extraídas de ECGs, na emissão de laudos. Neste sentido, propõe-se um Middleware para abstrair as complexidades e facilitar a construção de ferramentas que permitam a análise automática de ECGs. Na arquitetura proposta, um servidor disponibiliza os algoritmos computacionais para identificação das principais ondas presentes nos ECGs tais como complexo QRS, ondas P e T, e suporte aos padrões abertos de exames HL7 aECG e DICOM-ECG. Para validar o Middleware proposto e contribuir com a comunidade médica, em especial do Hospital Universitário Walter Cantídio, desenvolve-se uma aplicação Web para geração de laudos de ECGs acessível remotamente. Testes foram realizados com a solução proposta, utilizando-se a base de dados MIT-BIH Arrhythmia Database (MITDB) para simular os pacientes do sistema e produzir os resultados apresentados nesta dissertação. A solução proposta atendeu aos requisitos estabelecidos e representa uma solução viável, financeiramente e tecnicamente.
3

Estimation of geometric properties of three-component signals for condition monitoring / Estimation des propriétés géométriques de signaux à trois composantes pour la surveillance des systèmes

Phua, Gailene 07 January 2016 (has links)
La plupart des méthodes de surveillance des systèmes sont basées sur l'analyse et la caractérisation de grandeurs physiques qui sont par nature tridimensionnelles. Tracées dans un repère euclidien à trois dimensions, ces grandeurs parcourent en fonction du temps une trajectoire dont les caractéristiques géométriques sont représentatives de l'état du système surveillé. Les techniques classiques de surveillance des systèmes étudient les grandeurs mesurées composante par composante, sans prendre en compte leur nature tridimensionnelle et les propriétés géométriques de leur trajectoire. Une part importante de l'information est ainsi ignorée. Dans le cadre de ce travail de recherche, on se propose de développer une méthode d'analyse et de traitement de grandeurs à trois composantes permettant de mettre en évidence les spécificités géométriques des données et de fournir une information complémentaire pour la surveillance des systèmes. La méthode proposée a été appliquée à deux cas différents : la surveillance des creux de tension des réseaux de puissance triphasés et la surveillance des défauts de roulement des machines électriques tournantes. Dans ces deux cas, les résultats obtenus sont prometteurs et montrent que les indicateurs géométriques estimés mènent à de l'information complémentaire qui peut être utile pour la surveillance des systèmes. / Most methods for condition monitoring are based on the analysis and characterization of physical quantities that are three-dimensional in nature. Plotted in a three-dimensional Euclidean space as a function of time, these quantities follow a trajectory whose geometric characteristics are representative of the state of the monitored system. Usual techniques of condition monitoring study the measured quantities component by component, without taking into account their three-dimensional nature and the geometric properties of their trajectory. A significant part of the information is thus ignored. In this research work, we would therefore like to develop a method for the analysis and processing of three-component quantities capable of highlighting the special geometric features of such data and providing complementary information for condition monitoring. The proposed method has been applied to two different cases: voltage dips monitoring in three-phase power networks and bearing faults monitoring in rotating electrical machines. In this two cases, the results obtained are promising and show that the estimated geometric indicators lead to complementary information that can be useful for condition monitoring.

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