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Polynomial spline estimation of panel count data model with an unknown link function. Stat Pap (Berl) 2022. [DOI: 10.1007/s00362-022-01364-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2022]
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2
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Generalized Additive Model Reveals Nonlinear Trade-Offs/Synergies between Relationships of Ecosystem Services for Mountainous Areas of Southwest China. REMOTE SENSING 2022. [DOI: 10.3390/rs14122733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ecosystem services (ESs) are an essential link between ecosystems and human well-being, and trade-offs/synergies happen in ESs at different temporal and spatial scales. It is crucial to explore patterns of trade-offs/synergies among ESs, and their nonlinear relationships with changes in ESs. The primary objective of this study was to evaluate five ESs in 2000 and 2018: namely, water yield, food production, carbon sequestration, soil conservation, and habitat quality in mountainous regions of Southwest China. The mean values of the five ESs increased by 365.8 m3/ha, 13.92 t/hm2, 497.09 TgC/yr2, 138.48 t/km2, and 0.002, respectively. Using spatial statistics and analysis, an ES trade-off synergy model (ESTD) was constructed for the five ESs change values. Overall, soil conservation has a trade-off with all five ESs, except habitat quality; this trade-off is increasing slightly. Water yield is in synergy with all ESs except soil conservation, with decreasing synergy; habitat quality is in synergy with all ESs except food production, with increasing synergy. Finally, the nonlinear relationship between the value of the change in the ES and ESTD was analyzed using a generalized additive model. Changes in water yield showed the greatest impact on ESTD except for food production, wherein changes in all three ESs had minimal impacts on ESTD. Food production dominates its trade-offs/synergies relationship with soil conservation; carbon sequestration is the dominant player in its trade-offs/synergies relationship with soil conservation. Habitat quality has a secondary position of influence, except in the trade-offs/synergies involving food production. By exploring the drivers of trade-offs/synergies among ESs, this study can provide guidance for the effective implementation of policies related to ecological protection and restoration.
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Wang Y, Kim M, Yu S, Li X, Wang G, Wang L. Nonparametric estimation and inference for spatiotemporal epidemic models. J Nonparametr Stat 2021. [DOI: 10.1080/10485252.2021.1988084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Yueying Wang
- Department of Statistics, Iowa State University, Ames, IA, USA
| | - Myungjin Kim
- Department of Statistics, Iowa State University, Ames, IA, USA
| | - Shan Yu
- Department of Statistics, University of Virginia, Charlottesville, VA, USA
| | - Xinyi Li
- School of Mathematical and Statistical Sciences, Clemson University, Clemson, SC USA
| | - Guannan Wang
- Department of Mathematics, William & Mary College, Williamsburg, VA, USA
| | - Li Wang
- Department of Statistics, Iowa State University, Ames, IA, USA
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Liu R, Zhao Y. Empirical likelihood inference for generalized additive partially linear models. TEST-SPAIN 2021. [DOI: 10.1007/s11749-020-00731-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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5
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Cao G, Wang S, Wang L. Estimation and inference for functional linear regression models with partially varying regression coefficients. Stat (Int Stat Inst) 2020. [DOI: 10.1002/sta4.286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Guanqun Cao
- Department of Mathematics and Statistics Auburn University Auburn 36849 AL USA
| | - Shuoyang Wang
- Department of Mathematics and Statistics Auburn University Auburn 36849 AL USA
| | - Lily Wang
- Department of Statistics Iowa State University Ames 50011 IA USA
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Kinson C, Tang X, Zuo Z, Qu A. Longitudinal Principal Component Analysis With an Application to Marketing Data. J Comput Graph Stat 2019. [DOI: 10.1080/10618600.2019.1677244] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Christopher Kinson
- Department of Statistics, University of Illinois at Urbana-Champaign, Champaign, IL
| | - Xiwei Tang
- Department of Statistics, University of Virginia, Charlottesville, VA
| | - Zhen Zuo
- Department of Quantitative and Computational Biosciences, Baylor College of Medicine, Houston, TX
| | - Annie Qu
- Department of Statistics, University of Illinois at Urbana-Champaign, Champaign, IL
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Xiong X, Li R, Lian H. On nonparametric randomized sketches for kernels with further smoothness. Stat Probab Lett 2019. [DOI: 10.1016/j.spl.2019.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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8
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Yu S, Wang G, Wang L, Liu C, Yang L. Estimation and Inference for Generalized Geoadditive Models. J Am Stat Assoc 2019. [DOI: 10.1080/01621459.2019.1574584] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Shan Yu
- Department of Statistics, Iowa State University, Ames, IA
| | - Guannan Wang
- Department of Mathematics, College of William & Mary, Williamsburg, VA
| | - Li Wang
- Department of Statistics, Iowa State University, Ames, IA
| | - Chenhui Liu
- Turner-Fairbank Highway Research Center, Federal Highway Administration, McLean, VA
| | - Lijian Yang
- Center for Statistical Science and Department of Industrial Engineering, Tsinghua University, Beijing, China
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Lu M, Lu T, Li CS. Efficient estimation of partially linear additive Cox model under monotonicity constraint. J Stat Plan Inference 2018. [DOI: 10.1016/j.jspi.2017.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Liu R, Härdle WK, Zhang G. Statistical inference for generalized additive partially linear models. J MULTIVARIATE ANAL 2017. [DOI: 10.1016/j.jmva.2017.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Lu M. Spline-based quasi-likelihood estimation of mixed Poisson regression with single-index models. METRIKA 2017. [DOI: 10.1007/s00184-017-0631-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Lu M, Li CS. Penalized estimation for proportional hazards models with current status data. Stat Med 2017; 36:4893-4907. [PMID: 28872695 DOI: 10.1002/sim.7489] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/12/2017] [Accepted: 08/16/2017] [Indexed: 11/07/2022]
Abstract
We provide a simple and practical, yet flexible, penalized estimation method for a Cox proportional hazards model with current status data. We approximate the baseline cumulative hazard function by monotone B-splines and use a hybrid approach based on the Fisher-scoring algorithm and the isotonic regression to compute the penalized estimates. We show that the penalized estimator of the nonparametric component achieves the optimal rate of convergence under some smooth conditions and that the estimators of the regression parameters are asymptotically normal and efficient. Moreover, a simple variance estimation method is considered for inference on the regression parameters. We perform 2 extensive Monte Carlo studies to evaluate the finite-sample performance of the penalized approach and compare it with the 3 competing R packages: C1.coxph, intcox, and ICsurv. A goodness-of-fit test and model diagnostics are also discussed. The methodology is illustrated with 2 real applications.
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Affiliation(s)
- Minggen Lu
- School of Community Health Sciences, University of Nevada, Reno, NV, U.S.A
| | - Chin-Shang Li
- Division of Biostatistics, Department of Public Health Sciences, University of California, Davis, CA, U.S.A
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Song X, Wang L. Partially time-varying coefficient proportional hazards models with error-prone time-dependent covariates—an application to the AIDS Clinical Trial Group 175 data. Ann Appl Stat 2017. [DOI: 10.1214/16-aoas1003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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14
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Lu M. Efficient estimation of quasi-likelihood models using B-splines. ANN I STAT MATH 2016. [DOI: 10.1007/s10463-016-0575-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Li Z, Owzar K. Fitting Cox Models with Doubly Censored Data Using Spline-Based Sieve Marginal Likelihood. Scand Stat Theory Appl 2015; 43:476-486. [PMID: 27239090 DOI: 10.1111/sjos.12186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In some applications, the failure time of interest is the time from an originating event to a failure event, while both event times are interval censored. We propose fitting Cox proportional hazards models to this type of data using a spline-based sieve maximum marginal likelihood, where the time to the originating event is integrated out in the empirical likelihood function of the failure time of interest. This greatly reduces the complexity of the objective function compared with the fully semiparametric likelihood. The dependence of the time of interest on time to the originating event is induced by including the latter as a covariate in the proportional hazards model for the failure time of interest. The use of splines results in a higher rate of convergence of the estimator of the baseline hazard function compared with the usual nonparametric estimator. The computation of the estimator is facilitated by a multiple imputation approach. Asymptotic theory is established and a simulation study is conducted to assess its finite sample performance. It is also applied to analyzing a real data set on AIDS incubation time.
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Affiliation(s)
- Zhiguo Li
- Department of Biostatistics and Bioinformatics, Duke University
| | - Kouros Owzar
- Department of Biostatistics and Bioinformatics, Duke University
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Shujie MA, Carroll RJ, Liang H, Xu S. Estimation and Inference in Generalized Additive Coefficient Models for Nonlinear Interactions with High-Dimensional Covariates. Ann Stat 2015; 43:2102-2131. [PMID: 26412908 DOI: 10.1214/15-aos1344] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In the low-dimensional case, the generalized additive coefficient model (GACM) proposed by Xue and Yang [Statist. Sinica16 (2006) 1423-1446] has been demonstrated to be a powerful tool for studying nonlinear interaction effects of variables. In this paper, we propose estimation and inference procedures for the GACM when the dimension of the variables is high. Specifically, we propose a groupwise penalization based procedure to distinguish significant covariates for the "large p small n" setting. The procedure is shown to be consistent for model structure identification. Further, we construct simultaneous confidence bands for the coefficient functions in the selected model based on a refined two-step spline estimator. We also discuss how to choose the tuning parameters. To estimate the standard deviation of the functional estimator, we adopt the smoothed bootstrap method. We conduct simulation experiments to evaluate the numerical performance of the proposed methods and analyze an obesity data set from a genome-wide association study as an illustration.
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Ryu WS, Lee SH, Kim CK, Kim BJ, Kwon HM, Yoon BW. High serum alkaline phosphatase in relation to cerebral small vessel disease. Atherosclerosis 2014; 232:313-8. [DOI: 10.1016/j.atherosclerosis.2013.11.047] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 10/09/2013] [Accepted: 11/14/2013] [Indexed: 10/26/2022]
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21
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Park BU, Mammen E, Lee YK, Lee ER. Varying Coefficient Regression Models: A Review and New Developments. Int Stat Rev 2013. [DOI: 10.1111/insr.12029] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Lu M, Loomis D. Spline-based semiparametric estimation of partially linear Poisson regression with single-index models. J Nonparametr Stat 2013. [DOI: 10.1080/10485252.2013.817576] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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23
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Liu R, Yang L, Härdle WK. Oracally Efficient Two-Step Estimation of Generalized Additive Model. J Am Stat Assoc 2013. [DOI: 10.1080/01621459.2013.763726] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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24
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Li J, Gu M, Hu T. General partially linear varying-coefficient transformation models for ranking data. J Appl Stat 2012. [DOI: 10.1080/02664763.2012.658357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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