• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 1
  • Tagged with
  • 7
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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

Maria Jane McIntosh a woman in her time : a biographical and critical study.

Akili, Bashar. January 1990 (has links)
Thesis (doctoral)--University of Technology, Loughborough, 1990.
2

The Automated Solar Activity Prediction System (ASAP) Update Based on Optimization of a Machine Learning Approach

Abed, Ali K., Qahwaji, Rami S.R. 15 March 2022 (has links)
No / Quite recently, considerable attention has been paid to solar flare prediction because extreme solar eruptions could affect our daily life activities and on different technologies. Therefore, this paper presents a novel method of the development of improved second-generation of the Automated Solar Activity Prediction system (ASAP). The suggested algorithm improves the ASAP system by expanding a period of training vector and generating new machine learning rules to be more successful. Two neural networks are responsible for determining whether the sunspots group will release flare as well as determining if the flare is an M-class or X-class. Several measurement criteria are applied to determine the extent of system performance also all results are provided in this paper. Furthermore, the quadratic score (QR) is used as a metric criterion to compare between the prediction of the proposed algorithm with the Space Weather Prediction Center (SWPC) between 2012 and 2013. The results exhibit that the proposed algorithm outperforms the old ASAP system. Keywords: Solar flares, Machine Learning, Neural network, Space, Prediction, weather.
3

CLASSIFICAÇÃO DE TECIDOS DA MAMA A PARTIR DE IMAGENS MAMOGRÁFICAS EM MASSA E NÃO MASSA USANDO ÍNDICE DE DIVERSIDADE DE MCINTOSH E MÁQUINA DE VETORES DE SUPORTE / CLASSIFICATION OF TISSUE BREAST FROM MAMMOGRAPHIC IMAGES IN MASS AND NOT MASS USING INDEX OF DIVERSITY OF MCINTOSH AND SUPPORT VECTOR MACHINE

Carvalho, Péterson Moraes de Sousa 20 April 2012 (has links)
Made available in DSpace on 2016-08-17T14:53:21Z (GMT). No. of bitstreams: 1 Peterson.pdf: 1362910 bytes, checksum: 963fec328036941a0790b198cc0d6187 (MD5) Previous issue date: 2012-04-20 / FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTIFICO E TECNOLÓGICO DO MARANHÃO / Breast cancer is the second most common in the world and which more affects women. In recent years, several Computer Aided Detection/Diagnosis Systems has been developed in order to assist health specialists in the detection and diagnosis of cancer, serving as a second opinion. The aim of this paper is to present a methodology for discrimination and classification of regions extracted from mammograms in mass and non-mass. In this study, Digital Database for Screening Mammography (DDSM) is used. To describe the texture of the region of interest is applied McIntosh Diversity Index, commonly used in ecology. The calculation of this index is proposed in four approaches: through the Histogram, through the Gray Level Co-occurrence Matrix, through the Gray Level Run Length Matrix and through the Gray Level Gap Length Matrix. For the classification of regions in mass and non-mass, is used the supervised classificator Support Vector Machine (SVM). The methodology shows promising results for the classification of masses and non-masses, reaching an accuracy of 93,68%. / O câncer de mama é o segundo tipo de câncer mais frequente no mundo e o que mais acomete as mulheres. Nos últimos anos, vários Sistemas de Detecção e Diagnóstico auxiliados por Computador (Computer Aided Detection/Diagnosis) têm sido desenvolvidos no intuito de auxiliar especialistas da área da saúde na detecção e diagnóstico de câncer, servindo como uma segunda opnião. O objetivo deste trabalho é apresentar uma metodologia de discriminação e classificação de regiões extraídas de mamografias em massa e não massa. Neste estudo, o Digital Database for Screening Mammography (DDSM) é usado. Para descrever a textura da região de interesse é aplicado o Índice de Diversidade de McIntosh, comumente usado em ecologia. O cálculo deste índice é proposto em quatro abordagens: através do Histograma, da Matriz de Co-ocorrência de Níveis de Cinza, da Matriz de Comprimentos de Corrida de Cinza e da Matriz de Comprimentos de Lacuna de Cinza. Para classificação das regiões em massa e não massa, é utilizado o classificador supervisionado Support Vector Machine (SVM). A metodologia apresenta resultados promissores para a classificação de massas e não massas, alcançando uma acurácia de 93,68%.
4

Automatic Short-Term Solar Flare Prediction Using Machine Learning and Sunspot Associations.

Qahwaji, Rami S.R., Colak, Tufan January 2007 (has links)
Yes / In this paper, a machine-learning-based system that could provide automated short-term solar flare prediction is presented. This system accepts two sets of inputs: McIntosh classification of sunspot groups and solar cycle data. In order to establish a correlation between solar flares and sunspot groups, the system explores the publicly available solar catalogues from the National Geophysical Data Center to associate sunspots with their corresponding flares based on their timing and NOAA numbers. The McIntosh classification for every relevant sunspot is extracted and converted to a numerical format that is suitable for machine learning algorithms. Using this system we aim to predict whether a certain sunspot class at a certain time is likely to produce a significant flare within six hours time and if so whether this flare is going to be an X or M flare. Machine learning algorithms such as Cascade-Correlation Neural Networks (CCNNs), Support Vector Machines (SVMs) and Radial Basis Function Networks (RBFN) are optimised and then compared to determine the learning algorithm that would provide the best prediction performance. It is concluded that SVMs provide the best performance for predicting whether a McIntosh classified sunspot group is going to flare or not but CCNNs are more capable of predicting the class of the flare to erupt. A hybrid system that combines a SVM and a CCNN is suggested for future use. / EPSRC
5

Automated McIntosh-Based Classification of Sunspot Groups Using MDI Images

Colak, Tufan, Qahwaji, Rami S.R. 2007 December 1916 (has links)
yes / This paper presents a hybrid system for automatic detection and McIntosh-based classification of sunspot groups on SOHO/MDI white-light images using active-region data extracted from SOHO/MDI magnetogram images. After sunspots are detected from MDI white-light images they are grouped/clustered using MDI magnetogram images. By integrating image-processing and neural network techniques, detected sunspot regions are classified automatically according to the McIntosh classification system. Our results show that the automated grouping and classification of sunspots is possible with a high success rate when compared to the existing manually created catalogues. In addition, our system can detect and classify sunspot groups in their early stages, which are usually missed by human observers. / EPSRC
6

Engineering system design for automated space weather forecast : designing automatic software systems for the large-scale analysis of solar data, knowledge extraction and the prediction of solar activities using machine learning techniques

Alomari, Mohammad Hani January 2009 (has links)
Coronal Mass Ejections (CMEs) and solar flares are energetic events taking place at the Sun that can affect the space weather or the near-Earth environment by the release of vast quantities of electromagnetic radiation and charged particles. Solar active regions are the areas where most flares and CMEs originate. Studying the associations among sunspot groups, flares, filaments, and CMEs is helpful in understanding the possible cause and effect relationships between these events and features. Forecasting space weather in a timely manner is important for protecting technological systems and human life on earth and in space. The research presented in this thesis introduces novel, fully computerised, machine learning-based decision rules and models that can be used within a system design for automated space weather forecasting. The system design in this work consists of three stages: (1) designing computer tools to find the associations among sunspot groups, flares, filaments, and CMEs (2) applying machine learning algorithms to the associations' datasets and (3) studying the evolution patterns of sunspot groups using time-series methods. Machine learning algorithms are used to provide computerised learning rules and models that enable the system to provide automated prediction of CMEs, flares, and evolution patterns of sunspot groups. These numerical rules are extracted from the characteristics, associations, and time-series analysis of the available historical solar data. The training of machine learning algorithms is based on data sets created by investigating the associations among sunspots, filaments, flares, and CMEs. Evolution patterns of sunspot areas and McIntosh classifications are analysed using a statistical machine learning method, namely the Hidden Markov Model (HMM).
7

Engineering System Design for Automated Space Weather Forecast. Designing Automatic Software Systems for the Large-Scale Analysis of Solar Data, Knowledge Extraction and the Prediction of Solar Activities Using Machine Learning Techniques.

Alomari, Mohammad H. January 2009 (has links)
Coronal Mass Ejections (CMEs) and solar flares are energetic events taking place at the Sun that can affect the space weather or the near-Earth environment by the release of vast quantities of electromagnetic radiation and charged particles. Solar active regions are the areas where most flares and CMEs originate. Studying the associations among sunspot groups, flares, filaments, and CMEs is helpful in understanding the possible cause and effect relationships between these events and features. Forecasting space weather in a timely manner is important for protecting technological systems and human life on earth and in space. The research presented in this thesis introduces novel, fully computerised, machine learning-based decision rules and models that can be used within a system design for automated space weather forecasting. The system design in this work consists of three stages: (1) designing computer tools to find the associations among sunspot groups, flares, filaments, and CMEs (2) applying machine learning algorithms to the associations¿ datasets and (3) studying the evolution patterns of sunspot groups using time-series methods. Machine learning algorithms are used to provide computerised learning rules and models that enable the system to provide automated prediction of CMEs, flares, and evolution patterns of sunspot groups. These numerical rules are extracted from the characteristics, associations, and time-series analysis of the available historical solar data. The training of machine learning algorithms is based on data sets created by investigating the associations among sunspots, filaments, flares, and CMEs. Evolution patterns of sunspot areas and McIntosh classifications are analysed using a statistical machine learning method, namely the Hidden Markov Model (HMM).

Page generated in 0.0445 seconds