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3. A robust adaptive-to-model enhancement test for parametric single-index models

Author

Niu, Cuizhen and Zhu, Lixing

Subjects
Statistics - Methodology
Abstract

In the research on checking whether the underlying model is of parametric single-index structure with outliers in observations, the purpose of this paper is two-fold. First, a test that is robust against outliers is suggested. The Hampel's second-order influence function of the test statistic is proved to be bounded. Second, the test fully uses the dimension reduction structure of the hypothetical model and automatically adapts to alternative models when the null hypothesis is false. Thus, the test can greatly overcome the dimensionality problem and is still omnibus against general alternative models. The performance of the test is demonstrated by both Monte Carlo simulation studies and an application to a real dataset.

Published
2015

4. Enhancements of nonparametric generalized likelihood ratio test: Bias-correction and dimension reduction

Author

Niu, Cuizhen, Guo, Xu, and Zhu, Lixing

Subjects
Statistics - Methodology
Abstract

Nonparametric generalized likelihood ratio test is popularly used for model checking for regressions. However, there are two issues that may be the barriers for its powerfulness. First, the bias term in its liming null distribution causes the test not to well control type I error and thus Monte Carlo approximation for critical value determination is required. Second, it severely suffers from the curse of dimensionality due to the use of multivariate nonparametric function estimation. The purpose of this paper is thus two-fold: a bias-correction is suggested to this test and a dimension reduction-based model-adaptive enhancement is recommended to promote the power performance. The proposed test still possesses the Wilks phenomenon, and the test statistic can converge to its limit at a much faster rate and is much more sensitive to alternative models than the original nonparametric generalized likelihood ratio test as if the dimension of covariates were one. Simulation studies are conducted to evaluate the finite sample performance and to compare with other popularly used tests. A real data analysis is conducted for illustration.

Published
2015

14. Pembrolizumab in Chinese patients with advanced melanoma: 3-year follow-up of the KEYNOTE-151 study

Author

Si, Lu, primary, Zhang, Xiaoshi, additional, Shu, Yongqian, additional, Pan, Hongming, additional, Wu, Di, additional, Liu, Jiwei, additional, Mao, Lili, additional, Wang, Xuan, additional, Wen, Xizhi, additional, Gu, Yanhong, additional, Zhu, Lingjun, additional, Lan, Shijie, additional, Cai, Xin, additional, Diede, Scott J., additional, Dai, Haiyan, additional, Niu, Cuizhen, additional, Li, Jianfeng, additional, and Guo, Jun, additional

Published
2022
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17. KEYNOTE-991: pembrolizumab plus enzalutamide and androgen deprivation for metastatic hormone-sensitive prostate cancer.

Author

Gratzke, Christian, Kwiatkowski, Mariusz, De Giorgi, Ugo, Martins da Trindade, Karine, De Santis, Maria, Armstrong, Andrew J, Niu, Cuizhen, Liu, Yingjie, and Poehlein, Christian Heinrich

Abstract

Current treatment for patients with metastatic hormone-sensitive prostate cancer (mHSPC) delays disease progression and improves survival, but resistance is inevitable. Additional therapies that prolong survival are needed. Androgen deprivation therapy (ADT) combined with next-generation hormonal agents, such as enzalutamide, is standard-of-care for men with mHSPC. Emerging evidence suggests potential synergism between enzalutamide and the PD-1 inhibitor pembrolizumab in prostate cancer. The phase III randomized, placebo-controlled, double-blind KEYNOTE-991 trial will investigate the efficacy and safety of pembrolizumab versus placebo in combination with enzalutamide when initiating ADT in participants with mHSPC naive to next-generation hormonal agents. Approximately 1232 patients will be randomly assigned 1:1 to receive pembrolizumab 200 mg every 3 weeks or placebo every 3 weeks, both with enzalutamide 160 mg once daily and ADT. Dual primary end points are overall survival and radiographic progression-free survival. Secondary end points include time to first subsequent therapy, time to symptomatic skeletal related event, objective response rate and safety and tolerability. Clinical Trial Registration:NCT04191096 (ClinicalTrials.gov). The randomized, double-blind, phase III KEYNOTE-991 study will investigate the efficacy and safety of pembrolizumab versus placebo in combination with enzalutamide when initiating androgen deprivation therapy in participants with metastatic hormone sensitive prostate cancer naive to next-generation hormonal agents. [ABSTRACT FROM AUTHOR]

Published
2022
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21. Standard-Dose Pembrolizumab Plus Alternate-Dose Ipilimumab in Advanced Melanoma: KEYNOTE-029 Cohort 1C, a Phase 2 Randomized Study of Two Dosing Schedules

Author

Long, Georgina V., primary, Robert, Caroline, additional, Butler, Marcus O., additional, Couture, Felix, additional, Carlino, Matteo S., additional, O'Day, Steven, additional, Atkinson, Victoria, additional, Cebon, Jonathan S., additional, Brown, Michael P., additional, Dalle, Stéphane, additional, Hill, Andrew G., additional, Gibney, Geoffrey T., additional, McCune, Steven, additional, Menzies, Alexander M., additional, Niu, Cuizhen, additional, Ibrahim, Nageatte, additional, Moreno, Blanca Homet, additional, and Diab, Adi, additional

Published
2021
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22. Pembrolizumab plus enzalutamide for enzalutamide-resistant metastatic castration-resistant prostate cancer (mCRPC): Updated analyses after one additional year of follow-up from cohorts 4 and 5 of the KEYNOTE-199 study.

Author

Graff, Julie N, primary, Tagawa, Scott T., additional, Hoimes, Christopher J., additional, Gerritsen, Winald R., additional, Vaishampayan, Ulka N., additional, Elliott, Tony, additional, Hwang, Clara, additional, Ten Tije, A. J., additional, Omlin, Aurelius, additional, McDermott, Raymond S., additional, Fradet, Yves, additional, Kilari, Deepak, additional, Ferrario, Cristiano, additional, Uemura, Hiroji, additional, Niu, Cuizhen, additional, Poehlein, Christian Heinrich, additional, De Wit, Ronald, additional, Schloss, Charles, additional, De Bono, Johann S., additional, and Antonarakis, Emmanuel S., additional

Published
2021
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23. Second-line (2L) pembrolizumab (pembro) in Chinese patients (pts) with advanced melanoma: Three-year follow up (FU) of the phase 1 KEYNOTE-151 study.

Author

Guo, Jun, primary, Zhang, Xiaoshi, additional, Shu, Yongqian, additional, Pan, Hongming, additional, Wu, Di, additional, Liu, Jiwei, additional, Mao, Lili, additional, Wang, Xuan, additional, Wen, Xizhi, additional, Gu, Yanhong, additional, Zhu, Lingjun, additional, Lan, Shijie, additional, Cai, Xin, additional, Diede, Scott J., additional, Dai, Haiyan, additional, Niu, Cuizhen, additional, and Si, Lu, additional

Published
2021
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27. Standard-dose pembrolizumab (pembro) plus alternate-dose ipilimumab (ipi) in advanced melanoma: Initial analysis of KEYNOTE-029 cohort 1C.

Author

Long, Georgina V., primary, Robert, Caroline, additional, Butler, Marcus O., additional, Couture, Felix, additional, Carlino, Matteo S., additional, O'Day, Steven, additional, Atkinson, Victoria, additional, Cebon, Jonathan S., additional, Brown, Michael Paul, additional, Dalle, Stéphane, additional, Hill, Andrew Graham, additional, Gibney, Geoffrey Thomas, additional, McCune, Steven L., additional, Menzies, Alexander M., additional, Niu, Cuizhen, additional, Ibrahim, Nageatte, additional, Homet Moreno, Blanca, additional, and Diab, Adi, additional

Published
2019
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30. Theory and Application of an Economic Performance Measure of Risk

Author

Niu, Cuizhen, Guo, Xu, McAleer, Michael, and Wong, Wing-keung

Subjects
Economic performance measure, Bootstrap-based confidence interval, Estadística matemática, Matemáticas, Asymptotic confidence interval, ddc:330, C15, Econometría, Method of variance estimates recovery, C12
Abstract

Homm and Pigorsch (2012a) use the Aumann and Serrano index to develop a new economic performance measure (EPM), which is well known to have advantages over other measures. In this paper, we extend the theory by constructing a one-sample confidence interval of EPM, and construct confidence intervals for the difference of EPMs for two independent samples. We also derive the asymptotic distribution for EPM and for the difference of two EPMs when the samples are independent. We conduct simulations to show the proposed theory performs well for one and two independent samples. The simulations show that the proposed approach is robust in the dependent case. The theory developed is used to construct both onesample and two-sample confidence intervals of EPMs for Singapore and USA stock indices.

Published
2017

31. Estimation of the error distribution function for partial linear single-index models.

Author

Zhang, Jun, Niu, Cuizhen, Lu, Tao, and Wei, Zhenghong

Subjects
*DISTRIBUTION (Probability theory), *ERROR functions, *GAUSSIAN processes, *EMPIRICAL research
Abstract

We consider the estimation of the error distribution function of partial linear single-index models. The estimation methods for the error distribution function based on the classical empirical distribution function as well as empirical likelihood method are discussed, the latter method allows for incorporation of additional information on the error distribution function into estimation. We show weak convergence of the corresponding empirical processes to Gaussian processes and compare both approaches with the asymptotic theory and by means of simulation studies. [ABSTRACT FROM AUTHOR]

Published
2020
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42. Quantile regression estimation for distortion measurement error data.

Author

Zhang, Jun, Wang, Jiefei, Niu, Cuizhen, and Sun, Ming

Subjects
MATHEMATICAL variables, DIFFERENTIAL equations, MATHEMATICAL models, LINEAR algebra, MATRICES (Mathematics)
Abstract

We study the quantile estimation methods for the distortion measurement error data when variables are unobserved and distorted with additive errors by some unknown functions of an observable confounding variable. After calibrating the error-prone variables, we propose the quantile regression estimation procedure and composite quantile estimation procedure. Asymptotic properties of the proposed estimators are established, and we also investigate the asymptotic relative efficiency compared with the least-squares estimator. Simulation studies are conducted to evaluate the performance of the proposed methods, and a real dataset is analyzed as an illustration. [ABSTRACT FROM AUTHOR]

Published
2018
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50. Empirical likelihood for single index model with missing covariates at random.

Author

Guo, Xu, Niu, Cuizhen, Yang, Yiping, and Xu, Wangli

Subjects
*EMPIRICAL research, *CONFIDENCE intervals, *PARAMETER estimation, *CHI-squared test, *PERFORMANCE evaluation
Abstract

In this paper, we investigate the empirical-likelihood-based inference for the construction of confidence intervals and regions of the parameters of interest in single index models with missing covariates at random. An augmented inverse probability weighted-type empirical likelihood ratio for the parameters of interest is defined such that this ratio is asymptotically standard chi-squared. Our approach is to directly calibrate the empirical log-likelihood ratio, and does not need multiplication by an adjustment factor for the original ratio. Our bias-corrected empirical likelihood is self-scale invariant and no plug-in estimator for the limiting variance is needed. Some simulation studies are carried out to assess the performance of our proposed method. [ABSTRACT FROM AUTHOR]

Published
2015
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