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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

DEVELOPMENT AND COMPARATIVE ASSESSMENT OF CWT BASED DAMAGE DETECTION TECHNIQUES ON SIMULATED GEARBOX SIGNALS

RAGHUNATHAN, RAGHAVENDRAN 21 July 2006 (has links)
No description available.
2

Utveckling av provmetodik för HVAC på lastbil : Klimatprovning i klimatvindtunneln CD7 / Development of test methodology for truck HVAC : Climatic testing in the climatic wind tunnel CD7

Tedenäs, Jimmy, Jonsson, Björn-Emil January 2011 (has links)
The issue about how Scania shall perform HVAC tests in the climatic wind tunnel CD7, which Scania is about to complete by year 2013, has resulted in four test methods for truck HVAC and also a test method structure. The test methods have been chosen to focus on sun, snow and rain simulations. These are adapted and developed according to what should be tested and to what can be tested in CD7, which has been the object. With CD7 different climates can be simulated in a controlled environment for complete truck level, from desert with high sun load to arctic cold and snow. The test methods represents a basis to start from, for designers and test engineers which make the testing more repetitive as well as time eventually can be saved. Before the test methods can be applied they must be verified as they are based on theoretical and empirical assumptions. Test methods are not static and must be updated and developed continuously. By having a clear documentation with motivated choices for the methods, changes can easily be made. Another important part is for knowledge not to be lost over time. The aim with the master thesis has been that the study shall be basis for future testmethod development for HVAC at Scania. The structure makes an important component for documentation and the overview perspective. The structure is also flexible enough to be used for other test facilities, not only CD7, which should be a natural continuation. From the literature study in combination with interviews and observations, both internal and external, a modeling has emerged. Developed test methods have been discussed in a workshop with Scania personnel that gave feed-back to the methods. Performed interviews have demonstrated that explorative methods are usually made. At the same time the explorative testing evolve from established internal methods and requirement specifications. Requirement specification and testing are two subjects who have shown to be connected to each other. The interviews have also shown that solar simulations are among the most common tests concerning climate and HVAC.
3

Análise do comportamento dinâmico de ponte de concreto por meio de filtragem de sinais GPS / Analysis of the dynamic behavior of concrete bridges by GPS signals filtering

Oliveira, José Venâncio Marra 06 September 2018 (has links)
Esta pesquisa propôs uma contribuição aos procedimentos de inspeção de pontes por meio de um plano de monitoramento de curta duração do comportamento dinâmico do tabuleiro de pontes rodoviárias de concreto com a utilização de receptores GPS de 100 Hz associado à diversas técnicas de filtragem de sinais. O estudo foi conduzido em uma ponte em serviço localizada na rodovia Fernão Dias (BR-381). O procedimento de inspeção proposto baseou-se no uso de dois sinais de satélites GPS, por meio da aplicação do Método Residual de Fase (MRF), e da análise temporal dos resíduos da dupla diferença de fase a partir da Fast Fourier Transform (FFT), Continuous Wavelet Transform (CWT), Passa-Faixa Chebyshev do Tipo I. A descrição do comportamento dinâmico do tabuleiro do vão central da ponte se deu por meio da extração dos valores de frequência e amplitude das deflexões verticais a partir dos dados GPS filtrados (resíduos), em três períodos de amostragem de 1 minuto. Os valores de frequência variaram de 0,5 Hz a 8 Hz nos três períodos de amostragens e também nos filtros FFT, CWT e Passa-Faixa Chebyshev do Tipo I. Os valores de amplitude de deslocamento vertical máximo ficaram em torno de 6 mm. Estes valores coincidiram com os valores de frequência e amplitude de deslocamento vertical registrados pela instrumentação clássica com acelerômetros, transdutores de deslocamento vertical, modelagem por elementos finitos e prova de carga estática e dinâmica realizadas sobre tabuleiro do vão central da ponte instrumentado. Por fim, pode-se afirmar que os procedimentos propostos, além de poderem ser utilizados como uma etapa preliminar de inspeção de tabuleiro de pontes rígidas possibilitaram a detecção de deslocamentos dinâmicos verticais milimétricos e suas frequências de vibração. / This research proposed a contribution for bridge inspection procedures at of a short-term monitoring plan of the dynamic behavior of the concrete road bridge with the use of 100 Hz GPS receivers associated with various signal filtering techniques. The study was conducted in the service bridge located on the highway Fernão Dias (BR-381). The procedure inspection proposed was based on the use of two satellite GPS signals, by applying the Phase Residual Method (PRM), and the temporal analysis of the residuals of the double difference phase from the Fast Fourier Transform (FFT), Continuous Wavelet Transform (CWT), Type I Chebyshev Band-Pass. The dynamic behavior of the central span of the bridge was described by extracting the frequency and amplitude values of the vertical deflections from the filtered GPS data (residues), in three sampling periods of 1 minute. The frequency values found ranged from 0.5 Hz to 8 Hz in the three sampling periods as well as in the FFT, CWT and Chebyshev Type I Band-Pass filters. The maximum vertical displacement peak values were around 6 mm. These values coincided with the vertical displacement and amplitude values recorded by the classical instrumentation with accelerometers, vertical displacement transducers, finite element modeling and static and dynamic load test performed on the central span deck of the instrumented bridge. Finally, it could affirm that the procedures proposed, besides being able to be used as a preliminary step of inspection of the rigid bridge\'s deck enabled the detection of millimetric vertical dynamic displacements and their frequencies of vibration.
4

Detecção de agrupamento de microcalcificações em imagens de mamogramas digitalizados usando a transformada wavelet complexa de árvore dupla

Sá, Amandia de Oliveira 26 February 2016 (has links)
Submitted by Luciana Sebin (lusebin@ufscar.br) on 2016-10-06T13:19:49Z No. of bitstreams: 1 DissAOS.pdf: 12231590 bytes, checksum: 0d013d4adc46d9e7c5828719c8c6951f (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-13T20:24:59Z (GMT) No. of bitstreams: 1 DissAOS.pdf: 12231590 bytes, checksum: 0d013d4adc46d9e7c5828719c8c6951f (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-13T20:25:09Z (GMT) No. of bitstreams: 1 DissAOS.pdf: 12231590 bytes, checksum: 0d013d4adc46d9e7c5828719c8c6951f (MD5) / Made available in DSpace on 2016-10-13T20:25:19Z (GMT). No. of bitstreams: 1 DissAOS.pdf: 12231590 bytes, checksum: 0d013d4adc46d9e7c5828719c8c6951f (MD5) Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Mammography is considered the “gold standard"in the early detection of breast cancer, being this disease one of the greatest health problems of women worldwide. Clustered microcalcifications detected on mammograms are very important findings in asymptomatic patients with early breast cancer and may be considered one of the first signs of malignancy. However, due to the small size of these structures, associated with the visual fatigue of radiologists resulting from the analysis of a large volume of images, clinical studies indicate that from 10 to 30% of microcalcifications presented in mammograms are lost during diagnosis. Within this scenario, this master thesis aims to develop an automatic system for the detection of clustered microcalcifications in digitized mammography images. To solve this problem, we use the transformed dua-three complex wavelet to detect the microcalsifications since this technique has some important characteristics for the signal analysis, for instance, good directional selectivity, approximate shift invariance and it provides both information - magnitude and phase. After the detection of isolated microcalcifications, a post-processing step is used to automatically demarcate regions containing clusters of microcalcifications. Furthermore, three techniques were investigated for the analysis of each clustered detection in order to identify false-positive clusters, such as: the Hessian matrix, the groups exclusion and the gray level co-occurrence matrix technique and SVM classifiers. For the development and testing of the algorithms one digitized mammogram database were used. The analysis of the results were performed by using ROC and FROC curves. The method achieved good results when compared to the mark made by experts. / A mamografia é considerada o "padrão ouro"na detecção precoce do câncer de mama, sendo essa doença um dos maiores problemas de saúde da mulher no mundo. Agrupamentos de microcalcificações detectados nos mamogramas são achados muito importantes em pacientes assintomáticas com câncer de mama e podem representar o primeiro sinal de malignidade. No entanto, devido ao reduzido tamanho dessas estruturas, associado à fadiga visual dos radiologistas resultante da análise de grandes volumes de imagens, estudos clínicos indicam que de 10 a 30% das microcalcificações presentes nos mamogramas são perdidas durante o diagnóstico. Diante deste quadro, este trabalho de mestrado tem por objetivo o desenvolvimento de um sistema automático para a detecção de agrupamentos de microcalcificações em imagens de mamogramas digitalizados. Para isso, utilizou-se a transformada wavelet complexa de árvore dupla (DT-CWT) para a detecção das microcalcificações, visto que essa técnica possui características importantes para a análise de sinais como, por exemplo, boa seletividade direcional, invariância aproximada ao deslocamento e fornece ambas informações – magnitude e fase. Após a detecção das microcalcificações isoladas, uma etapa de pós-processamento foi utilizada para demarcar automaticamente regiões contendo agrupamentos de microcalcificações. Além disso, três técnicas foram investigadas para a análise de cada agrupamento detectado, com o intuito de identificar agrupamentos falsopositivos, sendo elas: a matriz Hessiana, a exclusão de agrupamentos e a técnica de matriz de coocorrência de níveis de cinza e classificadores SVMs. Uma base de dados de mamogramas digitalizados foi utilizada para o desenvolvimento e testes dos algoritmos. A análise dos resultados foi realizada usando curvas ROC e FROC. O método obteve bons resultados quando comparado às marcações realizadas por especialistas e presentes na base de dados.
5

Análise do comportamento dinâmico de ponte de concreto por meio de filtragem de sinais GPS / Analysis of the dynamic behavior of concrete bridges by GPS signals filtering

José Venâncio Marra Oliveira 06 September 2018 (has links)
Esta pesquisa propôs uma contribuição aos procedimentos de inspeção de pontes por meio de um plano de monitoramento de curta duração do comportamento dinâmico do tabuleiro de pontes rodoviárias de concreto com a utilização de receptores GPS de 100 Hz associado à diversas técnicas de filtragem de sinais. O estudo foi conduzido em uma ponte em serviço localizada na rodovia Fernão Dias (BR-381). O procedimento de inspeção proposto baseou-se no uso de dois sinais de satélites GPS, por meio da aplicação do Método Residual de Fase (MRF), e da análise temporal dos resíduos da dupla diferença de fase a partir da Fast Fourier Transform (FFT), Continuous Wavelet Transform (CWT), Passa-Faixa Chebyshev do Tipo I. A descrição do comportamento dinâmico do tabuleiro do vão central da ponte se deu por meio da extração dos valores de frequência e amplitude das deflexões verticais a partir dos dados GPS filtrados (resíduos), em três períodos de amostragem de 1 minuto. Os valores de frequência variaram de 0,5 Hz a 8 Hz nos três períodos de amostragens e também nos filtros FFT, CWT e Passa-Faixa Chebyshev do Tipo I. Os valores de amplitude de deslocamento vertical máximo ficaram em torno de 6 mm. Estes valores coincidiram com os valores de frequência e amplitude de deslocamento vertical registrados pela instrumentação clássica com acelerômetros, transdutores de deslocamento vertical, modelagem por elementos finitos e prova de carga estática e dinâmica realizadas sobre tabuleiro do vão central da ponte instrumentado. Por fim, pode-se afirmar que os procedimentos propostos, além de poderem ser utilizados como uma etapa preliminar de inspeção de tabuleiro de pontes rígidas possibilitaram a detecção de deslocamentos dinâmicos verticais milimétricos e suas frequências de vibração. / This research proposed a contribution for bridge inspection procedures at of a short-term monitoring plan of the dynamic behavior of the concrete road bridge with the use of 100 Hz GPS receivers associated with various signal filtering techniques. The study was conducted in the service bridge located on the highway Fernão Dias (BR-381). The procedure inspection proposed was based on the use of two satellite GPS signals, by applying the Phase Residual Method (PRM), and the temporal analysis of the residuals of the double difference phase from the Fast Fourier Transform (FFT), Continuous Wavelet Transform (CWT), Type I Chebyshev Band-Pass. The dynamic behavior of the central span of the bridge was described by extracting the frequency and amplitude values of the vertical deflections from the filtered GPS data (residues), in three sampling periods of 1 minute. The frequency values found ranged from 0.5 Hz to 8 Hz in the three sampling periods as well as in the FFT, CWT and Chebyshev Type I Band-Pass filters. The maximum vertical displacement peak values were around 6 mm. These values coincided with the vertical displacement and amplitude values recorded by the classical instrumentation with accelerometers, vertical displacement transducers, finite element modeling and static and dynamic load test performed on the central span deck of the instrumented bridge. Finally, it could affirm that the procedures proposed, besides being able to be used as a preliminary step of inspection of the rigid bridge\'s deck enabled the detection of millimetric vertical dynamic displacements and their frequencies of vibration.
6

Damage Detection In Beams By Wavelet Analysis

Yanilmaz, Huseyin 01 December 2007 (has links) (PDF)
In this thesis, a method proposed by Han et al. [40] for detecting and locating damage in a structural member was adapted. The method was based on the energies that were calculated from the CWT coefficients of vibrational response of a cantilever beam. A transverse cut at varying depths was introduced. The presence and location of crack was investigated by processing experimentally acquired acceleration signals. Results of modal analysis and wavelet analysis of the beam with different cut depths were compared. In addition, effect of using different mother wavelets in CWT analysis for damage detection capability was investigated. Acceleration data were analyzed through CWT at different scales and CWT coefficients were calculated. Those CWT coefficients obtained from different scales were evaluated from the standpoint of damage detection. Effectiveness of energy indices associated with CWT coefficients in damage detection was demonstrated as independent of the type of mother wavelet.
7

A Framework for policy-based Quality of Service for fixed broadband wireless networks

Parthasarathy, Rangaprabhu 10 July 2003 (has links)
This thesis describes an architecture for policy-based quality of service (QoS) for fixed broadband wireless systems. An implementation of the proposed architecture for the Local Multipoint Distribution Service (LMDS) wireless network in Blacksburg, Virginia is described in detail. The focus of the research work was to enable simpler management of the LMDS system and to design and enable network QoS. The thesis examines various means to provide QoS in the network. It highlights issues related to enabling QoS in the VT-LMDS network, like prioritized access, resource management, service differentiation, and lack of predictability in network performance. Quality of service assumes a definition based on the context and application of interest. This research focuses on enabling service differentiation and intelligent resource management based on network conditions and link utilization. A software application that serves as a model of the described architecture was developed using the C++ programming language. The tool uses the Simple Network Management Protocol (SNMP) for the network management operations. The design, implementation issues and the advantages and shortcomings of the tool are outlined and a short primer on the use of the tool is provided. Finally, possibilities for future work in this area especially towards enabling the tool to work with other vendor-specific LMDS systems and non-LMDS fixed broadband wireless systems are examined and the issues in implementing one such system are described. / Master of Science
8

Investigation of Factors Affecting Fertility: Chromosome Segregation Errors and Environmental Toxins

Jackson, Jodi Michelle 11 June 2007 (has links)
No description available.
9

Feature Extraction for the Cardiovascular Disease Diagnosis

Tang, Yu January 2018 (has links)
Cardiovascular disease is a serious life-threatening disease. It can occur suddenly and progresses rapidly. Finding the right disease features in the early stage is important to decrease the number of deaths and to make sure that the patient can fully recover. Though there are several methods of examination, describing heart activities in signal form is the most cost-effective way. In this case, ECG is the best choice because it can record heart activity in signal form and it is safer, faster and more convenient than other methods of examination. However, there are still problems involved in the ECG. For example, not all the ECG features are clear and easily understood. In addition, the frequency features are not present in the traditional ECG. To solve these problems, the project uses the optimized CWT algorithm to transform data from the time domain into the time-frequency domain. The result is evaluated by three data mining algorithms with different mechanisms. The evaluation proves that the features in the ECG are successfully extracted and important diagnostic information in the ECG is preserved. A user interface is designed increasing efficiency, which facilitates the implementation.
10

Digitální hudební efekt založený na waveletové transformaci jako plug-in modul / Digital musical effect as a plug-in module based on wavelet transform

Konczi, Róbert January 2011 (has links)
This work deals with theory of wavelet transform and Mallat’s algorithm. It also includes the programming method of creating VST plug-in modules and describes the developement of the plug-in module, witch uses the modificated coeficients of wavelet transform to applicate the music effect.

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