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A GIS Approach to Archaeological Settlement Patterns and Predictive Modeling in Chihuahua, MexicoFerguson, Haylie Anne 01 December 2018 (has links)
In this study I analyzed the pattern of settlement for known Medio period (A.D. 1200–1450) sites in the Casas Grandes region of Chihuahua, Mexico. Locational data acquired from survey projects in the Casas Grandes region were evaluated within a Geographic Information Systems (GIS) framework to reveal patterns in settlement and site distribution. Environmental and cultural variables, including aspect, cost distance to nearest ballcourt, ecoregion, elevation, local relief, cost distance to nearest oven, cost distance to Paquimé, slope, soil, terrain texture, topographic position index, cost distance to nearest trincheras, vegetation, vegetation variety to 100 meters, vegetation variety to 500 meters, cost distance to nearest intermittent lake, cost distance to nearest intermittent stream, cost distance to nearest perennial lake, and cost distance to nearest perennial stream were calculated for each site in this region. It was expected that the relationships of correspondence between known sites and these variables would provide a quantitative framework that could be used to model the locational probability of unknown sites in the region. Through the use of GIS and statistical analyses, the results of this study were used to produce an archaeological site sensitivity map for this region of northern Mexico.
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Comparative study of neural networks and design of experiments to the classification of HIV status / Wilbert Sibanda.Sibanda, Wilbert January 2013 (has links)
This research addresses the novel application of design of experiment, artificial neural net-works and logistic regression to study the effect of demographic characteristics on the risk of acquiring HIV infection among the antenatal clinic attendees in South Africa. The annual antenatal HIV survey is the only major national indicator for HIV prevalence in South Africa. This is a vital technique to understand the changes in the HIV epidemic over time. The annual antenatal clinic data contains the following demographic characteristics for each pregnant woman; age (herein called mother's age), partner's age (herein father's age), population group (race), level of education, gravidity (number of pregnancies), parity (number of children born), HIV and syphilis status. This project applied a screening design of experiment technique to rank the effects of individual demographic characteristics on the risk of acquiring an HIV infection. There are a various screening design techniques such as fractional or full factorial and Plackett-Burman designs. In this work, a two-level fractional factorial design was selected for the purposes of screening. In addition to screening designs, this project employed response surface methodologies (RSM) to estimate interaction and quadratic effects of demographic characteristics using a central composite face-centered and a Box-Behnken design. Furthermore, this research presents the novel application of multi-layer perceptron’s (MLP) neural networks to model the demographic characteristics of antenatal clinic attendees. A review report was produced to study the application of neural networks to modelling HIV/AIDS around the world. The latter report is important to enhance our understanding of the extent to which neural networks have been applied to study the HIV/AIDS pandemic. Finally, a binary logistic regression technique was employed to benchmark the results obtained by the design of experiments and neural networks methodologies. The two-level fractional factorial design demonstrated that HIV prevalence was highly sensitive to changes in the mother's age (15-55 years) and level of her education (Grades 0-13). The central composite face centered and Box-Behnken designs employed to study the individual and interaction effects of demographic characteristics on the spread of HIV in South Africa, demonstrated that HIV status of an antenatal clinic attendee was highly sensitive to changes in pregnant mother's age and her educational level. In addition, the interaction of the mother's age with other demographic characteristics was also found to be an important determinant of the risk of acquiring an HIV infection. Furthermore, the central composite face centered and Box-Behnken designs illustrated that, individual-ally the pregnant mother's parity and her partner's age had no marked effect on her HIV status. However, the pregnant woman’s parity and her male partner’s age did show marked effects on her HIV status in “two way interactions with other demographic characteristics”. The multilayer perceptron (MLP) sensitivity test also showed that the age of the pregnant woman had the greatest effect on the risk of acquiring an HIV infection, while her gravidity and syphilis status had the lowest effects. The outcome of the MLP modelling produced the same results obtained by the screening and response surface methodologies. The binary logistic regression technique was compared with a Box-Behnken design to further elucidate the differential effects of demographic characteristics on the risk of acquiring HIV amongst pregnant women. The two methodologies indicated that the age of the pregnant woman and her level of education had the most profound effects on her risk of acquiring an HIV infection. To facilitate the comparison of the performance of the classifiers used in this study, a receiver operating characteristics (ROC) curve was applied. Theoretically, an ROC analysis provides tools to select optimal models and to discard suboptimal ones independent from the cost context or the classification distribution. SAS Enterprise MinerTM was employed to develop the required receiver-of-characteristics (ROC) curves. To validate the results obtained by the above classification methodologies, a credit scoring add-on in SAS Enterprise MinerTM was used to build binary target scorecards comprised of HIV positive and negative datasets for probability determination. The process involved grouping variables using weights-of-evidence (WOE), prior to performing a logistic regression to produce predicted probabilities. The process of creating bins for the scorecard enables the study of the inherent relationship between demographic characteristics and an in-dividual’s HIV status. This technique increases the understanding of the risk ranking ability of the scorecard method, while offering an added advantage of being predictive.
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Comparative study of neural networks and design of experiments to the classification of HIV status / Wilbert Sibanda.Sibanda, Wilbert January 2013 (has links)
This research addresses the novel application of design of experiment, artificial neural net-works and logistic regression to study the effect of demographic characteristics on the risk of acquiring HIV infection among the antenatal clinic attendees in South Africa. The annual antenatal HIV survey is the only major national indicator for HIV prevalence in South Africa. This is a vital technique to understand the changes in the HIV epidemic over time. The annual antenatal clinic data contains the following demographic characteristics for each pregnant woman; age (herein called mother's age), partner's age (herein father's age), population group (race), level of education, gravidity (number of pregnancies), parity (number of children born), HIV and syphilis status. This project applied a screening design of experiment technique to rank the effects of individual demographic characteristics on the risk of acquiring an HIV infection. There are a various screening design techniques such as fractional or full factorial and Plackett-Burman designs. In this work, a two-level fractional factorial design was selected for the purposes of screening. In addition to screening designs, this project employed response surface methodologies (RSM) to estimate interaction and quadratic effects of demographic characteristics using a central composite face-centered and a Box-Behnken design. Furthermore, this research presents the novel application of multi-layer perceptron’s (MLP) neural networks to model the demographic characteristics of antenatal clinic attendees. A review report was produced to study the application of neural networks to modelling HIV/AIDS around the world. The latter report is important to enhance our understanding of the extent to which neural networks have been applied to study the HIV/AIDS pandemic. Finally, a binary logistic regression technique was employed to benchmark the results obtained by the design of experiments and neural networks methodologies. The two-level fractional factorial design demonstrated that HIV prevalence was highly sensitive to changes in the mother's age (15-55 years) and level of her education (Grades 0-13). The central composite face centered and Box-Behnken designs employed to study the individual and interaction effects of demographic characteristics on the spread of HIV in South Africa, demonstrated that HIV status of an antenatal clinic attendee was highly sensitive to changes in pregnant mother's age and her educational level. In addition, the interaction of the mother's age with other demographic characteristics was also found to be an important determinant of the risk of acquiring an HIV infection. Furthermore, the central composite face centered and Box-Behnken designs illustrated that, individual-ally the pregnant mother's parity and her partner's age had no marked effect on her HIV status. However, the pregnant woman’s parity and her male partner’s age did show marked effects on her HIV status in “two way interactions with other demographic characteristics”. The multilayer perceptron (MLP) sensitivity test also showed that the age of the pregnant woman had the greatest effect on the risk of acquiring an HIV infection, while her gravidity and syphilis status had the lowest effects. The outcome of the MLP modelling produced the same results obtained by the screening and response surface methodologies. The binary logistic regression technique was compared with a Box-Behnken design to further elucidate the differential effects of demographic characteristics on the risk of acquiring HIV amongst pregnant women. The two methodologies indicated that the age of the pregnant woman and her level of education had the most profound effects on her risk of acquiring an HIV infection. To facilitate the comparison of the performance of the classifiers used in this study, a receiver operating characteristics (ROC) curve was applied. Theoretically, an ROC analysis provides tools to select optimal models and to discard suboptimal ones independent from the cost context or the classification distribution. SAS Enterprise MinerTM was employed to develop the required receiver-of-characteristics (ROC) curves. To validate the results obtained by the above classification methodologies, a credit scoring add-on in SAS Enterprise MinerTM was used to build binary target scorecards comprised of HIV positive and negative datasets for probability determination. The process involved grouping variables using weights-of-evidence (WOE), prior to performing a logistic regression to produce predicted probabilities. The process of creating bins for the scorecard enables the study of the inherent relationship between demographic characteristics and an in-dividual’s HIV status. This technique increases the understanding of the risk ranking ability of the scorecard method, while offering an added advantage of being predictive.
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Incorporating survey weights into logistic regression modelsWang, Jie 24 April 2013 (has links)
Incorporating survey weights into likelihood-based analysis is a controversial issue because the sampling weights are not simply equal to the reciprocal of selection probabilities but they are adjusted for various characteristics such as age, race, etc. Some adjustments are based on nonresponses as well. This adjustment is accomplished using a combination of probability calculations. When we build a logistic regression model to predict categorical outcomes with survey data, the sampling weights should be considered if the sampling design does not give each individual an equal chance of being selected in the sample. We rescale these weights to sum to an equivalent sample size because the variance is too small with the original weights. These new weights are called the adjusted weights. The old method is to apply quasi-likelihood maximization to make estimation with the adjusted weights. We develop a new method based on the correct likelihood for logistic regression to include the adjusted weights. In the new method, the adjusted weights are further used to adjust for both covariates and intercepts. We explore the differences and similarities between the quasi-likelihood and the correct likelihood methods. We use both binary logistic regression model and multinomial logistic regression model to estimate parameters and apply the methods to body mass index data from the Third National Health and Nutrition Examination Survey. The results show some similarities and differences between the old and new methods in parameter estimates, standard errors and statistical p-values.
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Atributos que influyen en la decisión de compra de autos híbridos de la marca Toyota y Hyundai en comparación a adquirir autos convencionales en la zona 7 de Lima MetropolitanaObregon Corbella, Andres, Condor Sotil, Trilce 03 September 2019 (has links)
Esta investigación tiene como propósito identificar cuáles son los factores más determinantes para un posible comprador de un auto híbrido en comparación a un auto convencional en Lima Metropolitana, es por esto que se han utilizado herramientas cualitativas y cuantitativas para obtener un resultado; esto permitirá a las marcas de autos saber que factor es más importante para el consumidor y potenciarlo a través de estrategias de marketing directo e indirecto. En el análisis cualitativo desarrollado a través de un focus group se encontraron diferentes afirmaciones y negaciones que son respaldadas a través del análisis cuantitativo con el modelo estadístico logístico binario; en este caso se demostró que todas las variables son importantes para un posible comprador de un auto híbrido; pero unas tienen mayor importancia que otras y esto determinaría que se deben llevar a cabo estrategias que estén relacionadas al precio y diseño del auto; ya que son las variables que obtuvieron mayor importancia en el análisis. / This investigation has as purpose identify which are the factors more important for a possible buyer of a hybrid car in comparison of a conventional car in Lima Metropolitana, that is why qualitative and quantitative tools have been used to get a result; this will allow car brands to know which factor is more important for the consumer and to empower it through direct and indirect marketing strategies. In the qualitative analysis developed through a focus group, different affirmations and negations were found that are supported through quantitative analysis with the statistical binary logistic model; in this case it was shown that all the variables are important for a possible buyer of a hybrid car; but some are more important than others and this would determine that price and design should be the ones that have to have the focus of the strategies because they are the variables that obtained more importance in the statistical analysis. / Tesis
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台灣地區老年人健康與住宅所有權之關係張雅婷 Unknown Date (has links)
本文利用1999年,行政院衛生署家庭計畫研究所之「臺灣地區老人保健與生活問題長期追蹤調查系列研究調查資料」探討台灣地區老年人健康與住宅所有權之關係。實證方法採用binary logistic regression來探討模型一與模型二。模型一以三個健康指標來衡量老人健康狀態,第一個指標為主觀健康,即老年人認為本身是否健康,第二個指標為日常生活活動之限制 (ADLs),第三個指標為日常生活工具性活動 (IADLs)。得出結果若健康指標為IADLs和 ADLs則住宅所有權屬於自己和配偶的會比較健康。但是若以主觀健康衡量之,則住宅所有權對健康沒有顯著影響。模型二將住宅所有權分為二類,第一類為廣義自有屋,第二類為狹義自有屋。若是住宅所有權為廣義自有屋,則健康狀況對住宅所有權並沒有顯著影響。住宅所有權為狹義自有屋時,ADLs和IADLs方面越健康者,則越可能持有狹義自有屋。
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Analysis of the effectiveness of social protection as a means of alleviating poverty in South AfricaKhumalo, Mandla Lindsay 07 October 2016 (has links)
This research was conducted at Tsakane, Kwa-Thema, and Duduza, Ekurhuleni Metropolitan Municipality of Gauteng Province in South Africa. The objective of the study was to determine the effectiveness of social protection as a way of alleviating poverty in the study areas. The study was expected to contribute to the body of knowledge in social protection services as a way of alleviating poverty in the study areas. The study attempted to contribute to answers to the following research questions: (i) What are the socio-economic characteristics of the recipients of social protection measures in the three areas of study? (ii) What are the perceptions of the respondents about the South African government’s social protection in their areas? (iii) What are the factors that influence the effectiveness of social protection? Stratified random sampling with a proportional representation method was employed to select 200 respondents. The data collection tool used was simple closed-ended questionnaires. Interviews were conducted face-to-face with respondents. Statistical Package for Social Sciences (SPSS) version 21 of 2012 was used to analyse the data. Both descriptive statistics and binary logistic regression were employed. The results of the analysis revealed that the significant variables that had an effect on social protection were: the location of the respondents; their gender; their level of education; the type of dwelling of the respondents; and their income outside farming. The study recommends that the significant variables that had an effect on social protection be considered when measures of social protection measures are implemented / College of Agriculture and Environmental Sciences / M. Sc. (Agriculture)
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Influencia do uso de lubrificantes no processo de estampagem profunda com chapas espessas de aço / Influence of the lubricant use in the process of deep drawing with thick steel sheeet metalsSilva, Marco Fabricio Lopes Pereira da 14 August 2018 (has links)
Orientador: Sergio Tonini Button / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-14T01:25:30Z (GMT). No. of bitstreams: 1
Silva_MarcoFabricioLopesPereirada_M.pdf: 6009072 bytes, checksum: 9390e6123ad97adcd3ad0d0f7f347dc6 (MD5)
Previous issue date: 2007 / Resumo: O objetivo deste trabalho foi avaliar a influência da lubrificação sobre os esforços do processo e produto durante o embutimento profundo de corpos com chapas metálicas, conforme ABNT NBR 5906: 1984 grau EPA de espessura 3,5mm e entender as causas da fratura no produto durante o embutimento sobre condições específicas de processo. Ocorrências de defeitos como trincas, acabamentos indesejáveis, estrangulamentos, entre outros, em componentes estampados desse gênero e nessa ordem de espessura, justificam avaliar como o lubrificante atua sobre as características do processo de embutimento e quais são seus efeitos sobre as características dimensionais do produto. Para avaliar a ocorrência da fratura dos corpos de prova, foi realizado o primeiro conjunto de experimentos (sem lubrificantes) planejados pelo método fatorial, com a intenção de selecionar os corpos de prova para a segunda fase de experimentos. Os resultados foram coletados e analisados, podendo-se concluir nessa primeira fase que a probabilidade de fraturar o corpo de prova é maior em função do diâmetro externo do blanque do que em função do raio da ferramenta e que, a partir dos testes estatísticos não foi evidenciada a influência do prensa chapa sobre a probabilidade de fraturar o corpo de prova. Também nota-se que a não atuação do prensa chapa favorece a diminuição da força máxima de embutimento pela maior influência do raio da ferramenta. Quanto à ocorrência da fratura dos corpos de prova no segundo conjunto de experimentos planejados pelo método fatorial, com o objetivo de avaliar o desempenho de cinco lubrificantes, verificou-se que não houve influência da lubrificação sobre os resultados de fratura. Novamente foi identificada a relação com o raio da ferramenta (R) e com a atuação do prensa chapa, reforçando a hipótese de sensibilidade do produto em função da geometria da ferramenta. Avaliando-se os tipos de lubrificantes sobre a estricção da parede do produto em pontos específicos, observou-se uma deformação significativa quanto comparada com os resultados sem a aplicação de lubrificantes. Os cinco lubrificantes selecionados para os ensaios não minimizaram o efeito de fraturas nos corpos de prova, porém foi evidenciado efeito nos esforços de embutimento, destacando-se dos demais o lubrificante semi-sintético Extrudoil 319 HT. / Abstract: The objective of this work was to evaluate the influence of the lubrication on the process and product during the deep drawing of metallic cups, as Brazilian standard ABNT NBR 5906:1984, degree EPA to thickness 3,5mm and to understand the causes of the cracking during deep drawing, on specific conditions of this process. Occurrences of defects as crack, undesirable finishing, necking, among others, in stamped components in this level of thickness, justify evaluating the lubricant on the characteristics of the deep drawing process and the effect on the dimensional characteristics of the product. To evaluate the occurrence of cracking in the cups, it was planned the first set of experiments (without lubricant) with the factorial design, to select the cups for the second phase of experiments. The results had been collected and analyzed, being able to conclude in this first phase that the probability to crack the cup is bigger in function of the external diameter of blank, in function of the diameter of the tool, and according to the statistical tests, there were not evidences of the influence of the blank holder on the probability for cracking. Also without the blank holder there was a reduction of the maximum force of deep drawing because the biggest influence of the diameter of the tool. To evaluate the occurrence of cracking of the cups a second phase of experiments was planned with the factorial design, with the objective to evaluate the performance of five lubricants. It was verified that there was not influence of the lubrication on the cracking results; however it was again identified the relation with the diameter of the tool and with the performance of the blank holder, strengthening the hypothesis of sensitivity of the product in function of the geometry of the tool. Evaluating the five lubricants influence on the reduction of area of the cup wall in specific points, it was observed a significant deformation when compared with the results without lubricant. The five lubricants selected for the tests had not minimized the effect of cracking, however evidenced the effect in the deep drawing load, being the semi-synthetic lubricant Extrudoil 319 HT the best of these five lubricants. / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica
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Odhalení klíčových faktorů vzniku neshodných kusů v sériové výrobě / Detection of key factors of non-standard pieces in series productionBeňo, Tomáš January 2020 (has links)
The presented thesis deals with the issue of statistical quality control of a specific production process. The thesis presents a range of statistical tools that can be used to identify the factors causing a high proportion of non-standard pieces. The diploma thesis practically introduces the application of these quality management tools to the production process characterized by an increased proportion of non-standard pieces, in which the factors causing their occurrence are unknown, and as following the thesis in detail introduces the approach how to detect these factors. The last part of the work summarizes the recommendations handed over to the company in order to verify the conclusions of the thesis.
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Employing mHealth Applications for the Self-Assessment of Selected Eye Functions and Prediction of Chronic Major Eye Diseases among the Aging PopulationAbdualiyeva, Gulnara 24 May 2019 (has links)
In the epoch of advanced mHealth (mobile health) use in ophthalmology, there is a scientific call for regulating the validity and reliability of eye-related apps. For a positive health outcome that works towards enhancing mobile-application guided diagnosis in joint decision-making between eye specialists and individuals, the aging population should be provided with a reliable and valid tool for assessment of their eye status outside the physician office. This interdisciplinary study aims to determine through hypothesis testing validity and reliability of a limited set of five mHealth apps (mHAs ) and through binary logistic regression the prediction possibilities of investigated apps to exclude the four major eye diseases in the particular demographic population.
The study showed that 189 aging adults (45- 86 years old) who did complete the mHAs’ tests were able to produce reliable results of selected eye function tests through four out of five mHAs measuring visual acuity, contrast sensitivity, red desaturation, visual field and Amsler grid in comparison with a “gold standard” - comprehensive eye examination. Also, part of the participants was surveyed for assessing the Quality of Experience on mobile apps.
Understanding of current reliability of existing eye-related mHAs will lead to the creation of ideal mobile application’ self-assessment protocol predicting the timely need for clinical assessment and treatment of age-related macular degeneration, diabetic retinopathy, glaucoma and cataract. Detecting the level of eye function impairments by mHAs is cost-effective and can contribute to research methodology in eye diseases’ prediction by expanding the system of clear criteria specially created for mobile applications and provide returning significant value in preventive ophthalmology.
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