Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 34 for “"Cox Model"”.
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Modifications and extensions of the logistic regression and Cox model
In many statistical applications, the aim is to model the relationship between covariates and some outcomes. A choice of the appropriate model depends on the outcome and the research objectives, such as linear models for continuous outcomes, logistic models for binary outcomes and the Cox model for …
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DWCox: A density-weighted Cox model for outlier-robust prediction of prostate cancer survival
… provide hints about the disease mechanism. The Cox regression is currently a commonly accepted approach for such tasks in clinical applications. More complex methods, like ensemble approaches, have the potential of reaching better prediction accuracy at the cost of increased training difficulty …
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A Marginal Structural Cox Model Based Analysis Of The Comparative Effectiveness Of Two Dialysis Therapies
… modalities in the US, using marginal structural Cox models. The data set consists of 208,820 patients who initiated dialysis between January 1, 2007- December 31, 2011 at facilities owned by Davita corporation. Prior to presenting the data analysis, we provide a overview of the relevant concepts …
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Advances in Survival Analysis: Accurate Partial Likelihood Computation by Poisson-Binomial Distributions and Nonparametric Competing Risk Cox Model
… project revisits the partial likelihood in the Cox model, which traditionally approximates conditional probabilities using risk score ratios under a continuous-time assumption. We propose a new accurate partial likelihood computation method based on the Poisson-binomial distribution. Although …
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Statistical model on student performance in UTHM by using non-parametric, semi-parametric and parametric survival analysis
… performance, investigate the performance of Cox model based on the violation of the Proportional Hazard (PH) assumption, compare the model performance by using the survival and Accelerated Failure Time (AFT) models and estimate the time ratio (TR) of student performance in accordance to the …
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Application Of The Empirical Likelihood Method In Proportional Hazards Model
In survival analysis, proportional hazards model is the most commonly used and the Cox model is the most popular. These models are developed to facilitate statistical analysis frequently encountered in medical research or reliability studies. In analyzing real data sets, checking the validity of …
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A Cox proportional hazards-cash flow model for bank failure prediction
This research uses the Cox proportional hazard model and bank cash flow information to determine whether adding cash flow information will improve current bank failure prediction methods. In two published papers it has been shown that the Cox model performs as well as other models with respect to …
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Size and Power of Tests of Hypotheses on Parameters When Modeling Time-to-Event Data with the Lindley Distribution
… Such data are often analyzed by choosing a model that allows the covariate information to be utilized in the analyses. The analysis proceeds by estimating parameters in the model and testing hypotheses about the parameters based on their estimates; validity of inferences from tests of …
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Functional regression models in the frame work of reproducing kernel Hilbert space
… investigate some functional regression models for accurately quantifying the effect of functional predictors. In particular, three functional models are studied: functional linear regression model, functional Cox model, and function-on-scalar model. Both theoretical properties and …
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Longitudinal and survival statistical methods with applications in renal medicine
… on the subsequent kidney function. Joint modelling of longitudinal and time-to-event outcome and Cox model with time-varying covariate are considered to answer the first problem. Whilst parameters are estimated by maximum likelihood (ML) using an expectation-maximisation (EM) algorithm for …
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Credit Risk Modeling and Analysis Using Copula Method and Changepoint Approach to Survival Data
… and Student's t Copula as the main tools to model the credit risk in securitizations and re-securitizations. The second part proposes a statistical procedure to identify changepoints in Cox model of survival data. The recent 2007-2009 financial crisis has been regarded as the worst financial …
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Bayesian Hierarchical Frailty Models for Heterogeneity in Risk
… is most commonly estimated with the Cox model, which assumes proportional hazards. When heterogeneity in risk is present, the assumption of proportionality is violated and the Cox model's population-averaged estimate of the hazard ratio can underestimate the effect for an individual. …
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A Market-Based Approach for Valuing Ecosystem Services on Coastal Properties
… in Louisiana and Alabama using a hedonic price model. Understanding that tradeoffs must be made with limited resources, valuing ecosystem services is important for policy and decision making purposes, such as determining how much public and private financial resources should be put towards …
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Effectiveness of inhaled corticosteroids in preventing morbidity and mortality in individuals with chronic obstructive pulmonary disease and the impact of coexisting asthma
… individuals with COPD alone. We used an extended Cox model to estimate this association, with a time-varying measure of exposure to ICS. Results: We did not find any association between ICS and hazard of death or hospitalization among individuals with COPD alone (HR = 0.99; 95% CI: 0.94 – 1.05), …
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A Study of the Minimum p-value and Related Methods for the Identification of Treatment-Sensitive Groups
… under the framework of the generalized linear model with non-identity link function and the Cox model for respectively categorical and time to event clinical outcomes, bootstrap-based methods are proposed to adjust the profile methods for predictive classifications in both identifiable and …
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Essays on corporate bonds
… first chapter, I test the ability of structural models of default to price corporate bonds in the cross-section. I find that the Black-Cox model can explain 45% of the cross-sectional variation in yield spreads. The unexplained portion is correlated with proxies for credit risk and thus, cannot …
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Bayesian variable selection in high dimensional censored regression models
… in a high-dimensional censored regression model that can handle gene expression data with hundreds of thousands of features. We propose an EM-like iterative algorithm for accelerated failure models (AFT models) with censored survival data under no distributional assumption. Unlike existing …
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Modeling Mortality of Loblolly Pine Plantations
… Whole-stand and individual-tree mortality models were developed for loblolly pine plantations throughout its geographic range in the United States. The model for predicting stand mortality were developed using stand characteristics and biophysical variables. The models were constructed …
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Influence of missing explanatory variables and longitudinal assessments in breast cancer clinical trials
… data on explanatory variables in time-dependent Cox model analysis is explored, with application to breast cancer clinical trials. In particular, imputation in the context of time-dependent covariates that may be informative missing data which is described has not been studied in detail in the …
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Reframing Cox Proportional Hazards Model for Big Data and Neural Networks
… it is common to assume a proportional hazards model and fit a proportional hazards regression (or Cox regression). A log-concave objective function known as the “partial likelihood” is maximized to fit the Cox proportional hazards model. For moderate-sized datasets, an efficient Newton-Raphson …
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