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DC FieldValueLanguage
dc.contributorDepartment of Applied Mathematicsen_US
dc.contributor.advisorWong, Kin Yau (AMA)en_US
dc.contributor.advisorZhao, Xingqiu (AMA)en_US
dc.creatorNg, Hoi Min-
dc.identifier.urihttps://theses.lib.polyu.edu.hk/handle/200/13196-
dc.languageEnglishen_US
dc.publisherHong Kong Polytechnic Universityen_US
dc.rightsAll rights reserveden_US
dc.titleA study of semiparametric survival models with varying coefficientsen_US
dcterms.abstractSurvival analysis comprises a set of statistical tools for analyzing time-to-event outcomes. In biomedical studies, it is crucial to understand the association between risk factors and event times, such as death time or disease progression time. This understanding aids in identifying prognostic factors, predicting disease outcomes, and determining appropriate treatment strategies. Because the relationship between risk factors and event times is often complex, conventional survival models that assume a constant covariate effect could be inadequate. Varying-coefficient models have emerged as a flexible class of models that capture the intricate interaction effects among risk factors by allowing the covariate effects to depend on an index variable.en_US
dcterms.abstractThis research focuses on kernel-based estimation methods for varying-coefficient survival models, including the varying-coefficient additive hazards model and the varying-coefficient transformation model. While many existing kernel-based estimation methods rely on local neighborhoods of subjects to estimate the varying-coefficient functions, such local estimation methods may suffer efficiency loss when there exists a nuisance parameter that does not vary with the index variable. To improve efficiency, we propose a novel global approach that takes into account the shared nature of the nuisance parameter across subjects. In addition, we investigate a penalization method that combines the group lasso penalty with kernel smoothing techniques. This approach allows for the selection of important covariate effects, thereby enhancing the interpretability and predictive performance of the resulting model. Finally, we discuss an extension of the global approach to accommodate multiple index variables, enabling a more comprehensive analysis of the relationships between risk factors and event times.en_US
dcterms.extentxi, 91 pages : illustrationsen_US
dcterms.isPartOfPolyU Electronic Thesesen_US
dcterms.issued2024en_US
dcterms.educationalLevelPh.D.en_US
dcterms.educationalLevelAll Doctorateen_US
dcterms.LCSHFailure time data analysisen_US
dcterms.LCSHSurvival analysis (Biometry)en_US
dcterms.LCSHTime-series analysisen_US
dcterms.LCSHRegression analysisen_US
dcterms.LCSHHong Kong Polytechnic University -- Dissertationsen_US
dcterms.accessRightsopen accessen_US

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Please use this identifier to cite or link to this item: https://theses.lib.polyu.edu.hk/handle/200/13196