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 165 for “"Proportional Hazards"”.
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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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Extending Sample Size Calculation for the Cox Proportional Hazards Model
… used sample size formula derived under the Cox proportional hazards (PH) model may not be proper to design a survival trial with a cure fraction, since the PH model assumption may be violated. To account for a cure fraction, the PH cure model is widely used in practice, where a PH model is used …
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Reframing Cox Proportional Hazards Model for Big Data and Neural Networks
… outcome. To do this, 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 …
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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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Statistical model selection techniques for the cox proportional hazards model: a comparative study
… variable. In this dissertation, common Cox proportional hazards model selection techniques and a random survival forest technique were compared using five performance criteria measures. These performance measures were concordance index, integrated area under the curve, and , and R2 . To …
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Unified Approach to Partially Linear Model and Cox Proportional Hazards Model with Missing Covariates
… linear model (Engle et al., 1986) and Cox proportional hazards model (Cox, 1972) with missing covariates. The unified approach possesses some superior characteristics in dealing with regression models with missing data. First, the unified approach requires less extra assumptions to be …
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The analysis of limit orders using the Cox proportional hazards model with independent competing risks
I apply the Cox proportional hazards model with independent competing risks to study the hazard rates of executed, cancelled, and partially executed limit orders submitted for Microsoft to the Island ECN for one day. The instantaneous probability of execution increases with decreases in the buy …
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Optimal replacement in the proportional hazards model and its applications in a product-service system
… information into risk estimation is by the proportional hazards model (PHM), which explicitly includes both the age and the condition information in the calculation of the hazard function. This dissertation consists of three papers, in which the optimal replacement policies for systems whose …
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Optimal and Robust Designs of Step-stress Accelerated Life Testing Experiments for Proportional Hazards Models
… a product within a limited time frame. The Cox s proportional hazards (PH) model is often utilized for reliability prediction. My master thesis research focuses on designing accelerated life testing experiments for reliability estimation. We consider multiple step-stress ALT plans with censoring. …
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Modelling hepatotoxicity in HIV/TB co-infected patients: extensions of the Cox Proportional Hazards Model
Hepatotoxicity which is also known as liver damage is mainly caused by intake of medicine. It is common among patients who are co-administering Tuberculosis (TB) treatment and the antiretroviral therapy (ART) for the Human Immunodeficiency Viruses (HIV). If severe, hepatotoxicity sometimes …
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Sample Size Calculation Based on the Semiparametric Analysis of Short-term and Long-term Hazard Ratios
… sample size formulae for survival data with non-proportional hazard functions under both fixed and contiguous alternatives. Sample size determination has been widely discussed in literature for studies with failure-time endpoints. Many researchers have developed methods with the assumption of …
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A comparison of methods for analysing interval-censored and truncated survival data
… for analysing right-censored data: the Cox proportional hazards model (Cox, 1972), the Buckley-James regression model (Buckley and James, 1979) and the accelerated failure time model. These models are extended to incorporate the analysis of interval-censored and left-truncated data. The …
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Quantile Regression With Censored Data
… Quantile Regression; Kaplan-Meier; the Cox Proportional Hazards Model; Accelerated Failure Time Model.
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Survival Model and Estimation for Lung Cancer Patients.
… for the baseline hazard function and combine Cox proportional hazard regression for the survival study of a group of lung cancer patients. The covariates in the hazard function are estimated by maximum likelihood estimation following the proportional hazards regression analysis. Although the …
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Nuisance Parameter Estimation in Survival Models
The Cox proportional hazards model is the most commonly used method for right-censored data. Unfortunately, the interpretation of the hazard ratio is non-intuitive and it is commonly misinterpreted as a relative risk. This motivates alternative methods with more intuitive interpretations that avoid …
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Improving applicability of the non-monotone unified estimate for missing data
… unified estimate and its application to the Cox proportional hazards model for survival data. We present a new R program which can be used to easily fit the unified estimate for generalized linear models or Cox proportional hazards models. Possible hypothesis tests for the fit of the unified …
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Application of dynamic prediction models for longitudinal biomarkers and clinical outcomes in low and middle-income settings
… over traditional approaches such as the Cox proportional hazards-based prediction model. In addition to applying an extension of existing models to correctly model semicontinuous biomarker data (two-part joint model), this thesis challenges this assumption by applying dynamic prediction …
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The Competing Risks of Prepayment and Default on the Single-Family Mortgage Market
… characteristics.</p> <p>In earlier studies, the proportional hazards model becomes a popular method to analyze the single (prepayment or default) risk of mortgages. This model has been developed into a competing risks model and been widely used to analyze the prepayment and default risks …
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Modeling Mortality of Loblolly Pine Plantations
… structure of the data. Semiparametric proportional hazards regression was also used to develop model for individual-tree mortality. Shared frailty model, mixed model extension of Cox proportional hazards model, was used to account for unobserved heterogeneity not explained by the …
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Topics in Bayesian models with ordered parameters : response misclassification, covariate misclassification, and sample size determination.
… We examine a parametric Bayesian Weibull proportional hazards model with ordered covariate misclassification and provide an adjustment for it. Finally, we consider informative hypotheses (Hoijtink, 2012) and perform sample size determination for this problem using the two priors approach …
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