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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.
101

Paternal Ages and Genetic Diseases and Congenital Anomalies

Hamood, Neda 01 January 2021 (has links)
The purpose of this thesis is to investigate the link between advanced paternal ages (APA) (i.e., APA ≥ 35 years and APA ≥ 50 years) and genetic diseases and congenital anomalies. Currently, the relationship between both advanced paternal ages and genetic diseases and congenital anomalies remains unclear. However, there is room for improvement to systematically investigate the relationship between specific congenital anomalies in newborns and advanced paternal ages. More recently, the link between advanced paternal age (as opposed to existing studies analyzing advanced maternal age alone) and genetic diseases has been recognized by researchers, epidemiologists, and various health experts. Thus, this study serves to examine the effect of advanced paternal ages on the likelihood of birth defects using a new dataset intended to discover those relationships. I create three different datasets and utilize 12 statistical models to analyze the relationship between advanced paternal ages (APA ≥ 35 years and APA ≥ 50 years) (while including advanced maternal age or AMA [AMA ≥ 35 years]) and genetic diseases and congenital anomalies. I focus on Down syndrome, cleft lip with or without cleft palate, and meningocele/spina bifida and explore the relationship between both advanced parental ages. I explore whether (a) the advanced paternal ages and (b) the advanced maternal age increase the likelihood of newborn reproductive defects: (a) Down syndrome, (b) cleft lip with or without cleft palate, and (c) meningocele/spina bifida. This study includes all U.S. births between 2016 and 2019 using the CDC Natality Registry[1] database (2020). I perform the analyses using logistic regression models (to estimate odds ratios) that provide explanations of the relationship between each birth defect and advanced paternal ages. Analysis results suggest that advanced paternal ages (APA ≥ 35 years and APA ≥ 50 years) are positively associated with Down syndrome, whereas advanced paternal age (APA ≥ 35 years) is negatively associated with cleft lip with or without cleft palate. The results from the advanced paternal ages models do not suggest any causal relationship/effect on spina bifida. The results of this study are expected to offer some insight of the following reproductive defects: (a) Down syndrome, (b) cleft lip with or without cleft palate, and (c) meningocele/spina bifida. [1] Collection of data for all variables used in this research are obtained with full permission from: United States Department of Health and Human Services (US DHHS), Centers for Disease Control and Prevention" "(CDC), National Center for Health Statistics (NCHS), Division of Vital Statistics, Natality public-use data 2016-2019, on CDC" WONDER Online Database, October 2020. Accessed at http://wonder.cdc.gov/natality-expanded-current.html on Jun 6, 2021, 1:24:47 PM;" United States Department of Health and Human Services (US DHHS), Centers for Disease Control and Prevention" "(CDC), National Center for Health Statistics (NCHS), Division of Vital Statistics, Natality public-use data 2016-2019, on CDC" "WONDER Online Database, October 2020. Accessed at http://wonder.cdc.gov/natality-expanded-current.html on Jun 6, 2021, 1:29:36 PM;" And United States Department of Health and Human Services (US DHHS), Centers for Disease Control and Prevention""(CDC), National Center for Health Statistics (NCHS), Division of Vital Statistics, Natality public-use data 2016-2019, on CDC" "WONDER Online Database, October 2020. Accessed at http://wonder.cdc.gov/natality-expanded-current.html on Jun 6, 2021, 1:07:36 PM."
102

Detection and localization of link-level network anomalies using end-to-end path monitoring / Détection et localisation des anomalies réseau au niveau des liens en utilisant de la surveillance des chemins de bout-en-bout

Salhi, Emna 13 February 2013 (has links)
L'objectif de cette thèse est de trouver des techniques de détection et de localisation des anomalies au niveau des liens qui soient à faible coût, précises et rapides. La plupart des techniques de détection et de localisation des anomalies au niveau des liens qui existent dans la littérature calculent les solutions, c-à-d l'ensemble des chemins à monitorer et les emplacements des dispositifs de monitorage, en deux étapes. La première étape sélectionne un ensemble minimal d'emplacements des dispositifs de monitorage qui permet de détecter/localiser toutes les anomalies possibles. La deuxième étape sélectionne un ensemble minimal de chemins de monitorage entre les emplacements sélectionnés de telle sorte que tous les liens du réseau soient couverts/distinguables paire par paire. Toutefois, ces techniques ignorent l'interaction entre les objectifs d'optimisation contradictoires des deux étapes, ce qui entraîne une utilisation sous-optimale des ressources du réseau et des mesures de monitorage biaisées. L'un des objectifs de cette thèse est d'évaluer et de réduire cette interaction. A cette fin, nous proposons des techniques de détection et de localisation d'anomalies au niveau des liens qui sélectionnent les emplacements des moniteurs et les chemins qui doivent être monitorés conjointement en une seule étape. Par ailleurs, nous démontrons que la condition établie pour la localisation des anomalies est suffisante mais pas nécessaire. Une condition nécessaire et suffisante qui minimise le coût de localisation considérablement est établie. Il est démontré que les deux problèmes sont NP-durs. Des algorithmes heuristiques scalables et efficaces sont alors proposés. / The aim of this thesis is to come up with cost-efficient, accurate and fast schemes for link-level network anomaly detection and localization. It has been established that for detecting all potential link-level anomalies, a set of paths that cover all links of the network must be monitored, whereas for localizing all potential link-level anomalies, a set of paths that can distinguish between all links of the network pairwise must be monitored. Either end-node of each path monitored must be equipped with a monitoring device. Most existing link-level anomaly detection and localization schemes are two-step. The first step selects a minimal set of monitor locations that can detect/localize any link-level anomaly. The second step selects a minimal set of monitoring paths between the selected monitor locations such that all links of the network are covered/distinguishable pairwise. However, such stepwise schemes do not consider the interplay between the conflicting optimization objectives of the two steps, which results in suboptimal consumption of the network resources and biased monitoring measurements. One of the objectives of this thesis is to evaluate and reduce this interplay. To this end, one-step anomaly detection and localization schemes that select monitor locations and paths that are to be monitored jointly are proposed. Furthermore, we demonstrate that the already established condition for anomaly localization is sufficient but not necessary. A necessary and sufficient condition that minimizes the localization cost drastically is established. The problems are demonstrated to be NP-Hard. Scalable and near-optimal heuristic algorithms are proposed.
103

An analysis of monthly calendar anomalies in the Pakistani stock market : a study of the Gregorian and Islamic calendars

Halari, Anwar January 2013 (has links)
Most of the prior research in the area of monthly regularities has been based on the Gregorian calendar; by contrast, little attention has been given to other calendars based on different religions or cultures. This thesis examines monthly calendar anomalies in the Pakistani stock market for both the Gregorian calendar and its Islamic counterpart. This is one of the first studies to investigate both calendars for monthly seasonality in one investigation on the same dataset. Empirical studies of the Pakistani stock market that have examined monthly calendar anomalies are relatively sparse when compared with investigations from other emerging markets throughout the world. Even the findings from the small number of Pakistani investigations that have examined for the presence of monthly calendar anomalies have arrived at different conclusions about the predictability of equity returns at different times within a year. Since the conclusions of these findings have been mixed, the current study undertakes further work on this topic to offer some clarity in this area; this thesis arrives at a firm conclusion about the monthly calendar anomaly. For the purpose of this thesis, both qualitative and quantitative research methods were employed. Firstly, 19 face-to-face interviews were conducted with brokers, regulators and individual investors to ascertain their views about share price regularities with regards to monthly calendar anomalies and to gain some insights about the role of investor sentiment in the Pakistani stock markets. Secondly, share returns for a sample of 106 companies listed on the KSE over the 17 year period from 1995 to 2011 were analysed to determine whether Pakistani stock markets are weak-form efficient or whether security price changes can be predicted from knowledge of the month when the return is earned; it also investigates whether there is a change in the risk (volatility) of shares in different months which might explain any pattern in returns. To answer these questions various research methods were employed. The results of the interviews suggest that most respondents believed that share prices exhibit patterns in certain months of the year. The most common pattern highlighted by the interviewees related to the month of January for the Gregorian calendar and Ramadan for the Islamic calendar. Interviewees also argued that volatility declined during the religious month of Ramadan; they attributed these changes to investor sentiment and religious duties. Overall, the results suggested that monthly calendar anomalies may be present in the market and that these are studied by investors in an attempt to earn profit. The results from the quantitative analyses supported the findings from the interviews. Initial analyses suggested that returns varied significantly during certain months which indicate that the market might not be efficient. Further, investigations for seasonality in both the mean and volatility of returns offered conflicting evidence; very little statistical evidence of monthly seasonal anomalies was identified in average returns. However, monthly patterns were present in the variance of equity price changes in Pakistan. Overall, the results confirm that whatever monthly seasonality may be present in the equity prices of Pakistani companies, it is more pronounced in the volatility data than in the mean return numbers. These findings may have useful implications for trading strategies and investment decisions; investors may look to gain from managing the risk of their portfolios due to time varying volatility documented in the findings of this thesis. Further, the results of this thesis have interesting implications for our understanding of the dynamics of equity volatility in the Pakistani stock market.
104

Выявление аномалий технологического процесса на примере макета очистной установки воды SWaT (Secure Water Treatment) : магистерская диссертация / Identification of technological process anomalies using the example of a mock-up of a SWaT (Secure Water Treatment) water treatment plant

Жериборова, Е. В., Zheriborova, E. V. January 2023 (has links)
Цель работы – анализ моделей машинного обучения, направленных на обнаружение аномалий на промышленных предприятиях, использующих автоматизированные системы управления технологическим процессом, а также выявление причин аномалий. Объектом исследования является выявление аномалий во время работы технологического оборудования, агрегатов, установок, отдельных производств – выявление атак на датчик или группу датчиков. Рассматриваются основные модели машинного обучения, позволяющие выявлять аномалии, которые могут возникать при попытках внешнего воздействия, так и при технологических неисправностях промышленного производства. Рассмотрена модель – AutoEncoder. Оценена точность предсказания применяемой модели ML. / The purpose of the work is to analyze machine learning models aimed at detecting anomalies at industrial enterprises using automated process control systems, as well as identifying the causes of anomalies. The object of the study is to identify anomalies during the operation of technological equipment, units, installations, individual industries - identifying attacks on a sensor or group of sensors. The main models of machine learning are considered, allowing to identify anomalies that can arise during attempts of external influence, as well as during technological malfunctions of industrial production. The model considered is AutoEncoder. The prediction accuracy of the applied ML model is assessed.
105

Effect of market anomalies on expected returns on the JSE: A cross-sector analysis

Mahlophe, Mpho Innocentia January 2015 (has links)
The efficient market hypothesis and behavioural finance have been the cause of much debate for decades, with one theory advocating market efficiency and the other opposing it. The efficient market hypothesis (EMH) assumes that investors always act rationally and stock prices adjust rapidly to new information and should reflect all available information. In contrast, behavioural finance suggests that markets are not rational and investors make irrational decisions, which may lead them to over- or under-price stocks. Researchers for years have been empirically testing these assumptions in stock markets. However, there has been no consensus on which asset-pricing models perform better in capturing the effect of market anomalies and what impact these market anomalies have on the expected returns of different stock market’s sectors. The aim of the study was to test the effect of selected market anomalies on expected return in different sectors of the Johannesburg Stock Exchange (JSE). More specifically, the study aimed to compare the performance of different asset-pricing models and their ability to account for market anomalies in different sectors of the JSE. Additionally, this study tested the applicability of the recent Fama and French five (FF5-factor) model, in estimating the expected return on the JSE. The study used a quantitative approach with secondary data over a period of 12 years starting from January 2002 to December 2014. The sample used in the study consists of monthly data obtained from McGregor BFA and the South African Reserve Bank. The study examined for the effects of size, value, January and momentum variables across six sectors of the JSE. This was accomplished by the use of various asset-pricing models such as the Capital asset pricing model (CAPM), the Fama and French three-factor model (FF3-factor), the Carhart four-factor model (C4F) and the recent five-factor model of Fama and French (FF5-factor). The study showed that whenever the asset-pricing models were not restricted, they tend to capture the market anomalies in four out of the six sectors examined. However, no market anomalies were found present in two of the six sectors analysed. In contrast, when the asset-pricing models are restricted, the asset-pricing models only seem to capture the effects of market anomalies in one of the six examined sectors. The findings in this study suggest that market anomalies are sensitive to model specifications, as restricting the models tends to capture the different market anomalies across the sectors of the JSE. The study also found that market anomalies differ across sectors and that some sectors are more efficient than others. The study also reveals that the FF5-factor model is able to account for expected returns on the JSE. In addition, the FF5-factor model tends to perform better when the model is restricted. It is also evident from the findings presented in this study, that the value anomaly loses its predictive power when profitability and investment variables are included in the model. Overall, the study illustrated that market anomalies have an effect on returns of the JSE, that the model specifications play an important role in an asset-pricing model and that the FF5-factor model is applicable on the JSE, however, it is not certain whether four or five factors apply to the South African market.
106

Effect of market anomalies on expected returns on the JSE: A cross-sector analysis

Mahlophe, Mpho Innocentia January 2015 (has links)
The efficient market hypothesis and behavioural finance have been the cause of much debate for decades, with one theory advocating market efficiency and the other opposing it. The efficient market hypothesis (EMH) assumes that investors always act rationally and stock prices adjust rapidly to new information and should reflect all available information. In contrast, behavioural finance suggests that markets are not rational and investors make irrational decisions, which may lead them to over- or under-price stocks. Researchers for years have been empirically testing these assumptions in stock markets. However, there has been no consensus on which asset-pricing models perform better in capturing the effect of market anomalies and what impact these market anomalies have on the expected returns of different stock market’s sectors. The aim of the study was to test the effect of selected market anomalies on expected return in different sectors of the Johannesburg Stock Exchange (JSE). More specifically, the study aimed to compare the performance of different asset-pricing models and their ability to account for market anomalies in different sectors of the JSE. Additionally, this study tested the applicability of the recent Fama and French five (FF5-factor) model, in estimating the expected return on the JSE. The study used a quantitative approach with secondary data over a period of 12 years starting from January 2002 to December 2014. The sample used in the study consists of monthly data obtained from McGregor BFA and the South African Reserve Bank. The study examined for the effects of size, value, January and momentum variables across six sectors of the JSE. This was accomplished by the use of various asset-pricing models such as the Capital asset pricing model (CAPM), the Fama and French three-factor model (FF3-factor), the Carhart four-factor model (C4F) and the recent five-factor model of Fama and French (FF5-factor). The study showed that whenever the asset-pricing models were not restricted, they tend to capture the market anomalies in four out of the six sectors examined. However, no market anomalies were found present in two of the six sectors analysed. In contrast, when the asset-pricing models are restricted, the asset-pricing models only seem to capture the effects of market anomalies in one of the six examined sectors. The findings in this study suggest that market anomalies are sensitive to model specifications, as restricting the models tends to capture the different market anomalies across the sectors of the JSE. The study also found that market anomalies differ across sectors and that some sectors are more efficient than others. The study also reveals that the FF5-factor model is able to account for expected returns on the JSE. In addition, the FF5-factor model tends to perform better when the model is restricted. It is also evident from the findings presented in this study, that the value anomaly loses its predictive power when profitability and investment variables are included in the model. Overall, the study illustrated that market anomalies have an effect on returns of the JSE, that the model specifications play an important role in an asset-pricing model and that the FF5-factor model is applicable on the JSE, however, it is not certain whether four or five factors apply to the South African market.
107

An Analysis and Interpretation of Gravity and Magnetic Anomalies of the Butte District, Montana

Ahrens, Gary Louis January 1976 (has links)
An interpretation of gravity and magnetic anomalies of the Butte district, Montana, is based on the analysis of five gravity profiles constructed from Bouguer gravity data of the Butte district observed during the summer of 1974 and give concurrent magnetic profiles constructed from U.S. Geological Survey high-level aeromagnetic data of the district. Of primary concern in this analysis is the interpretation of the Bouguer gravity high and aeromagnetic low associated with the Butte orebody. Results of this interpretation yield a configuration for the Butte orebody characterized by vertical contacts extending from the surface or directly beneath Cenozoic basin fill to 4,500 feet below sea level, with a central core, elongate in the north -south direction, surrounded by a variable outer zone, which is more pronounced in the southern and western portions of the district. The central core is interpreted as a region of zero magnetic susceptibility with three density distributions, all of which are of higher densities than the surrounding host rock and are related to the varying degrees of mineralization and alteration present in this region. The laterally variable outer zone is interpreted as a zone of low magnetic susceptibility with a density equal to that of the host rock. This zone is related to the peripheral mineralization and alteration of the Butte orebody.
108

Multivariate GLS meta-analysis on ambient air pollution and congenital heart anomalies

Wang, Ni 09 October 2014 (has links)
The effects of air pollutants CO, NO₂, O₃, PM₁₀ and SO₂ on congenital heart anomalies are represented by the odds ratio of each disease per unit increase in the concentration of each pollutant. In this study, the effects of air pollutants are summarized using multivariate GLS approach with correlation between outcomes being taken into account, where the correlations are sampled from uniform [-1,1]. Meta-analysis conducted here found no statistically significant increase in odds ratio of any disease. This result is different from what Vrijheid et al. 2011 suggested when correlation is not considered using the same set of data. The difference in conclusions from the two meta-analysis indicate that correlation between outcomes may play an important role when synthesizing effect sizes. Thus, before conduct meta-analysis, a thorough consideration about whether to incorporate the correlation in synthesizing should be given. / text
109

Gravity anomalies, flexure and the thermo-mechanical evolution of the West Iberia Margin and its conjugate of Newfoundland

Cunha, Tiago January 2008 (has links)
The West Iberia (WIM) and Newfoundland (NFM) continental margins formed over a succession of rift events related to the opening of the North Atlantic between the Late Triassic and the Early Cretaceous. They are characterized by a variable width Ocean- Continent Transition (Zone) where exhumed and serpentinized mantle has been cored. Results from 1-D well backstripping along the Portuguese shelf suggest 40-45% greater extension factors (β) than previous estimates. In addition, the age and duration of both the Late Triassic-earliest Jurassic and the Late Jurassic rifting episodes have been better constrained. It appears, for example, that the Late Jurassic rift propagates northwards along the margin, as inferred for the continental break-up during the Early Cretaceous. Combined backstripping and gravity modelling techniques (POGM), together with new bathymetry and sediment thickness grids, have been used to estimate the effective elastic thickness, T<sub>e</sub>, of the lithosphere. Results along closely space profiles in the WIM reveal that T<sub>e</sub> decreases from 15-40 km over unthinned Variscan basement to ≤ 15 km over stretched continental and transitional crust. Along strike, a good correlation is found between the modelled mechanical structure and the segmentation of the Variscan basement onshore. Discrepancies between observed and calculated anomalies are discussed in terms of other processes that affected the margin, such as serpentinization and inversion. Thermo-mechanical rheological modelling techniques have also been tested. The compiled software inputs the β's constrained from POGM to determine the thermal structure of the margin, which, in turn, has been used to construct models of rheology and, hence, T<sub>e</sub>. The models predict an increase in the T<sub>e</sub> of thinned continental lithosphere with age since rifting, between < 20 and > 35 km, and suggest that processes such as ductile shearing and mantle serpentinization might have permanently weakened the lithosphere. Results from POGM along conjugate profiles off WI and NF reveal a greater longterm strength of extended continental and transitional basement in the NFM (T<sub>e</sub>'s of 10-40 km). This analysis further supports the hypothesis that the low T<sub>e</sub>'s modelled in the WIM might be related to its complex structural framework. In order to explain the large asymmetries observed in the amount of basement subsidence (500-1300 in) between the WI and NF margins a lithospheric-scale "simple shear" rift model is proposed for the latest stages of rifting and continental break-up.
110

Effets de l'amnioinfusion en présence de liquide amniotique méconial épais sur les anomalies du rythme cardiaque foetal

Calvet, Marie January 2005 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

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