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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

Nailfold capillary loop shape analysis and classification by using image processing and pattern recognition techniques

Oral, Mustafa January 1998 (has links)
Nailfold capillaroscopy is a useful tool to diagnose endocrine, cardiovascular, neuropsychiatric, rheumatic and other diseases. Diagnoses are made on the presence or absence of certain types of capillary loops which are classified according to their shape. We have surveyed six clinicians, asking them to classify 217 capillary loops, in order to establish quantitative nailfold capillary loop classification criteria. The participating clinicians were not unanimous about the classification of any capillary, and there was no consensus about the class of 17% of the capillary loops. Some of the clinicians classified two occurrences of the same shape differently. This clearly demonstrates the need for well established classification criteria. Nailfold capillary loop classes can be divided into two major groups: Descriptive Classes (DC); "cuticulis", "open", "tortuous", "crossed", "bizarre" and "bushy", and Label Classes; "enlarged", "elongated" and "giant". Furthermore label classes can be divided into two groups, Width Anomaly Classes (WAC); "enlarged" and "giant", and Length Anomaly Class (LAC), "elongated". While descriptive classes give information about the shape of a loop, label classes emphasise dimensional anomalities of a loop. Assignment of a loop with one the descriptive or label classes causes information loss about the dimensions or shape, respectively. In order to preserve as much information as possible within a class, we propose a new class system that contains 17 classes which are the combination of WAC, LAC and DC. We propose quantitative classification criteria for commonly used classes: "cuticulis", "open", "tortuous", "elongated" and "giant". Although the class "enlarged" can be expressed quantitatively, inappropriate assignments of "enlarged" by the paricipating clinicians have not allowed us to set quantitative classification criteria. While definition of the class "crossed" is purely qualitative, a classification mechanism that is neither qualitative nor quantitative is proposed for "bizarre" and "bushy" loops. We propose the use of pattern recognition algorithms that are based on the evaluation of the capillary shape parameters such as loop length, loop width, limb width, the curvature, orientation, etc., to classify capillaries. By the use of mathematical morphology, skeletonization, topological relations, feature vectors, in an hierarchical structure, the software TANCCAS (The Automated Nailfold Capillary Classification and Analysis System) has been developed to calculate the shape parameters and to classify the capillary loops. These algorithms have been implemented on a Pentium PC and have resulted in an 88% accuracy level which is compared to participating clinicians' overall classifications of the test images.
2

Concepts of Innovation for and from Emerging Markets

Albert, Martin 09 November 2016 (has links) (PDF)
A closer look at innovation for and from emerging markets respectively developing economies reveals that a variety of different terms and concepts related to this type of innovation exist. The goal of my conceptual paper is to present a comprehensive overview of related terms and concepts and to suggest theoretical based classification criteria in order to differentiate them. After a first investigation in relation to innovation for and from emerging markets the keywords ‘reverse’, ‘frugal’, ‘jugaad’, and ‘bottom of the pyramid / bottom of pyramid / bop’ were identified and used for searching the database of Google Scholar. For further investigation only texts were considered with at least eight various terms. 19 different texts were identified which classified for a further analysis. As results 33 identified terms in relation to innovation for and from emerging markets, various spellings and synonyms and references with at least two mentions in the identified texts are presented. As theoretical based classification criteria ‘market orientation’, ‘determinants’ (of innovation for and from emerging market)’, ‘nature’ (of innovation for and from emerging markets), sophistication’, ‘sustainability’, ‘novelty’ and ‘innovator type’ were identified.
3

Modelos Mistura de Regressão na Segmentação de Mercado: uma abordagem metodológica para a selecção do número adequado de segmentos. Estudo do comportamento do utente de transporte público urbano na área metropolitana do Porto

Brochado, Ana Margarida Mendes Camelo Oliveira 10 October 2007 (has links)
Ciências Empresariais (sem parte escolar) / Esta dissertação enquadra-se na problemática da segmentação de mercado e da selecção do número de grupos quando são utilizados modelos mistura de regressão para variáveis normais. Apesar do frequente uso destes modelos, o problema da selecção do número de segmentos continua em aberto, quer na literatura de Marketing, quer Estatística. Determinar o número de segmentos é essencial, na medida em que várias decisões estratégicas de Marketing em mercados heterogéneos dependem dela, existindo custos para as empresas de uma incorrecta definição do número de segmentos de mercado. Esta dissertação possui dois objectivos de investigação: (i) identificação, descrição e organização dos critérios, dispersos na literatura, que podem ser usados na selecção do número de segmentos; (ii) avaliação da eficácia dos critérios revistos e da influência de um conjunto de condições experimentais na selecção do número de segmentos. Os critérios foram classificados em dois grandes grupos, critérios de informação (estimadores da distância Kullback-Leibler, bayesianos e consistentes) e critérios de classificação (índices probabilísticos e índices difusos). A avaliação do desempenho dos 26 critérios seleccionados foi efectuada através de um conjunto de 17 designs experimentais. Na sua concepção deu-se particular relevância ao problema de nichos de mercado e à questão da robustez dos resultados à distribuição de probabilidade assumida (normal versus uniforme). As simulações foram realizadas no programa Gauss 6.0. Os melhores desempenhos foram dos critérios AIC3, AIC4, HQ, ICLBIC e ICOMPLBIC. Na presença de amostras de grande dimensão e um grande número de grupos são igualmente recomendáveis os critérios BIC e CAIC. / This dissertation is developed in the context of market segmentation and market segments retention when mixture regression models for normal data are used. Despite the popularity of these models, the decision of how many segments to keep is an open issue, both in Marketing and Statistics literature. To determine the correct number of market segments is essential, because many strategic Marketing decisions in heterogeneous markets depend on it and an incorrect selection of the number of market segments results in monetary costs for any company. This dissertation has two main objectives: (i) identification, description and classification of the criteria that could be used to select the number of market segments (ii) evaluation of how the reviewed criteria perform and the influence of a set of experimental conditions on the selection of the number of market segments. The reviewed criteria were classified into two groups, namely information criteria (Kullback-Leibler, bayesian and consistent) and classification criteria (probabilistic and fuzzy indices). The performance evaluation of the 26 selected criteria was accomplished through a set of 17 experimental designs. In these experimental designs we considered the problem of market niches and the robustness of the results to the probability assumed (normal versus uniform). The simulations were implemented with Gauss 6.0 package. The best results were obtained for the criteria AIC3, AIC4, HQ, ICLBIC and ICOMPLBIC. BIC and CAIC also perform well with large samples and a large number of market segments.
4

Concepts of Innovation for and from Emerging Markets

Albert, Martin 09 November 2016 (has links)
A closer look at innovation for and from emerging markets respectively developing economies reveals that a variety of different terms and concepts related to this type of innovation exist. The goal of my conceptual paper is to present a comprehensive overview of related terms and concepts and to suggest theoretical based classification criteria in order to differentiate them. After a first investigation in relation to innovation for and from emerging markets the keywords ‘reverse’, ‘frugal’, ‘jugaad’, and ‘bottom of the pyramid / bottom of pyramid / bop’ were identified and used for searching the database of Google Scholar. For further investigation only texts were considered with at least eight various terms. 19 different texts were identified which classified for a further analysis. As results 33 identified terms in relation to innovation for and from emerging markets, various spellings and synonyms and references with at least two mentions in the identified texts are presented. As theoretical based classification criteria ‘market orientation’, ‘determinants’ (of innovation for and from emerging market)’, ‘nature’ (of innovation for and from emerging markets), sophistication’, ‘sustainability’, ‘novelty’ and ‘innovator type’ were identified.
5

Toward new criteria for systemic lupus erythematosus: a standpoint

Aringer, M., Dörner, T., Leuchten, N., Johnson, S. R. 27 September 2019 (has links)
While clearly different in their aims and means, classification and diagnosis both try to accurately label the disease patients are suffering from. For systemic lupus erythematosus (SLE), this is complicated by the multi-organ nature of the disease and by our incomplete understanding of its pathophysiology. Hallmarks of SLE are the presence of antinuclear antibodies (ANA), and multiple immune-mediated organ symptoms that are largely independent. In an attempt to overcome limitations of the current sets of SLE classification criteria, a new fourphase approach is being developed, which is jointly supported by the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR). This review attempts to delineate the performance of the current sets of criteria, the reasons for the decision for classification, and not diagnostic, criteria, and to provide a background of the current approach taken.

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