Luo Xiao

Also known as: Luo

Functional data analysis; Longitudinal data analysis; Smoothing; Semiparametric regression; high di

I am a statistician interested in developing functional data methods for applications in biostatistics including neuroimaging, wearable computing and growth data.

Works (42)

Updated: April 4th, 2024 03:36

2023 journal article

BAYESIAN INFERENCE AND DYNAMIC PREDICTION FOR MULTIVARIATE LONGITUDINAL AND SURVIVAL DATA

ANNALS OF APPLIED STATISTICS, 17(3), 2574–2595.

By: H. Zou*, D. Zeng*, L. Xiao n & S. Luo*

author keywords: Alzheimer's disease; multivariate longitudinal data; functional mixed model; joint model; Bayesian method; dynamic prediction
TL;DR: This work proposes a joint model based on a multivariate functional mixed model framework (referred to as MFMM-JM) that simultaneously models the multiple longitudinal outcomes and the time to dementia onset and develops six functional forms to fully investigate the complex association between longitudinal outcome and dementia onset. (via Semantic Scholar)
Sources: Web Of Science, NC State University Libraries
Added: November 6, 2023

2023 article

Latent factor model for multivariate functional data

Li, R., & Xiao, L. (2023, September 4). BIOMETRICS, Vol. 9.

By: R. Li n & L. Xiao n

author keywords: covariance function; fPCA; functional data; model identifiability; penalized splines
TL;DR: For multivariate functional data, a functional latent factor model is proposed, extending the traditional latent factor model for multivariate data and may provide a more parsimonious and interpretable characterization of the otherwise complex dependencies between the functions. (via Semantic Scholar)
Sources: Web Of Science, NC State University Libraries
Added: September 11, 2023

2023 article

Multivariate functional mixed model with MRI data: An application to Alzheimer's disease

Zou, H., Xiao, L., Zeng, D., & Luo, S. (2023, February 20). STATISTICS IN MEDICINE, Vol. 2.

By: H. Zou*, L. Xiao n, D. Zeng* & S. Luo*

author keywords: Alzheimer's disease; Bayesian method; dynamic prediction; functional regression; magnetic resonance imaging
MeSH headings : Humans; Alzheimer Disease; Magnetic Resonance Imaging; Neuroimaging; Brain / diagnostic imaging; Brain / pathology; Disease Progression; Cognitive Dysfunction / diagnostic imaging
TL;DR: A dynamic prediction framework that provides accurate personalized predictions of longitudinal trajectories and survival probability is developed and applied to the ADNI study and significant associations among longitudinal outcomes, MRI data, and the risk of dementia onset are identified. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Sources: Web Of Science, NC State University Libraries
Added: March 20, 2023

2022 article

Fast Multilevel Functional Principal Component Analysis

Cui, E., Li, R., Crainiceanu, C. M., & Xiao, L. (2022, October 7). JOURNAL OF COMPUTATIONAL AND GRAPHICAL STATISTICS, Vol. 10.

By: E. Cui*, R. Li n, C. Crainiceanu* & L. Xiao n

author keywords: Functional principal component analysis; Mixed model equations; Multilevel models
TL;DR: This work introduces fast multilevel functional principal component analysis (fast MFPCA), which scales up to high dimensional functional data measured at multiple visits, and achieves comparable estimation accuracy with the originalMFPCA. (via Semantic Scholar)
UN Sustainable Development Goal Categories
2. Zero Hunger (OpenAlex)
Sources: Web Of Science, NC State University Libraries
Added: October 24, 2022

2022 article

Fixed-effects inference and tests of correlation for longitudinal functional data

Li, R., Xiao, L., Smirnova, E., Cui, E., Leroux, A., & Crainiceanu, C. M. (2022, May 1). STATISTICS IN MEDICINE, Vol. 5.

By: R. Li n, L. Xiao n, E. Smirnova*, E. Cui*, A. Leroux* & C. Crainiceanu*

author keywords: accelerometry data; covariance function; hypothesis test; mixed effects model
MeSH headings : Computer Simulation; Exercise; Humans; Longitudinal Studies; Research Design
UN Sustainable Development Goal Categories
Sources: Web Of Science, NC State University Libraries
Added: May 10, 2022

2022 article

Functional data analysis for longitudinal data with informative observation times

Weaver, C., Xiao, L., & Lu, W. (2022, March 28). BIOMETRICS, Vol. 3.

By: C. Weaver n, L. Xiao n & W. Lu n

author keywords: functional data analysis; informative observation times; longitudinal data; penalized splines
MeSH headings : Models, Statistical; Longitudinal Studies; Computer Simulation
UN Sustainable Development Goal Categories
Sources: Web Of Science, NC State University Libraries, ORCID
Added: February 22, 2022

2022 journal article

Joint model for survival and multivariate sparse functional data with application to a study of Alzheimer's Disease

BIOMETRICS, 78(2), 435–447.

By: C. Li*, L. Xiao n & S. Luo*

author keywords: EM algorithm; functional mixed model; multivariate longitudinal data; smoothing; survival
MeSH headings : Alzheimer Disease / diagnostic imaging; Databases, Factual; Disease Progression; Humans; Neuroimaging / methods
TL;DR: A multivariate functional mixed model is proposed to identify the shared progression pattern and outcome‐specific progression patterns of the outcomes, which enables more interpretable modeling of associations between outcomes and AD onset. (via Semantic Scholar)
Sources: Web Of Science, NC State University Libraries
Added: March 1, 2021

2022 article

Two-stage linked component analysis for joint decomposition of multiple biologically related data sets

Chen, H., Caffo, B., Stein-O'Brien, G., Liu, J., Langmead, B., Colantuoni, C., & Xiao, L. (2022, March 31). BIOSTATISTICS, Vol. 3.

author keywords: Integrative methods; Joint decomposition; Low rank models; Multiview data; Principal component analysis
MeSH headings : Computer Simulation; Humans; Transcriptome
UN Sustainable Development Goal Categories
Sources: Web Of Science, NC State University Libraries
Added: May 2, 2022

2021 journal article

A functional mixed model for scalar on function regression with application to a functional MRI study

BIOSTATISTICS, 22(3), 439–454.

By: W. Ma n, L. Xiao n, B. Liu n & M. Lindquist*

author keywords: fMRI; Functional data analysis; Functional mixed model; Functional principal component; Repeated measurements; Variance component testing
MeSH headings : Brain / diagnostic imaging; Computer Simulation; Humans; Magnetic Resonance Imaging; Principal Component Analysis
TL;DR: The model extends the standard scalar on function regression for repeated outcomes by incorporating subject-specific random functional effects and can be reformulated as a mixed effects model and thus easily fit. (via Semantic Scholar)
Sources: Web Of Science, NC State University Libraries, ORCID
Added: January 15, 2020

2021 journal article

Fetal growth velocity standards from the Fetal Growth Longitudinal Study of the INTERGROWTH-21 st Project

AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY, 224(2).

By: E. Ohuma*, J. Villar*, Y. Feng n, L. Xiao n, L. Salomon*, F. Barros*, L. Ismail*, W. Stones* ...

MeSH headings : Abdomen / diagnostic imaging; Abdomen / embryology; Adult; Crown-Rump Length; Female; Femur / diagnostic imaging; Femur / embryology; Fetal Development; Gestational Age; Growth Charts; Head / diagnostic imaging; Head / embryology; Humans; Infant, Newborn; Internationality; Longitudinal Studies; Male; Pregnancy; Ultrasonography, Prenatal; Young Adult
TL;DR: The fetal skeleton and abdomen have different velocity growth patterns during intrauterine life and this study provides an application that can be used easily in clinical practice to evaluate changes in fetal size as conditional velocity for a more refined assessment of fetal growth than is possible at present. (via Semantic Scholar)
Sources: Web Of Science, NC State University Libraries
Added: March 15, 2021

2021 article

Single-index models with functional connectivity network predictors

Weaver, C., Xiao, L., & Lindquist, M. A. (2021, May 5). BIOSTATISTICS, Vol. 5.

By: C. Weaver n, L. Xiao n & M. Lindquist*

author keywords: fMRI; Networks; Nonparametric regression; Penalized splines; Sparsity
MeSH headings : Humans; Nerve Net / diagnostic imaging; Nerve Net / physiology; Connectome / methods; Magnetic Resonance Imaging / methods; Brain / diagnostic imaging; Brain / physiology; Computer Simulation
TL;DR: A single-index model wherein response variables and sparse functional connectivity network valued predictors are linked by an unspecified smooth function in order to accommodate potentially nonlinear relationships is proposed. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Sources: Web Of Science, NC State University Libraries, ORCID
Added: July 5, 2021

2020 journal article

Asymptotic properties of penalized splines for functional data

BERNOULLI, 26(4), 2847–2875.

By: L. Xiao n

author keywords: L-2 convergence; functional data analysis; nonparametric regression; penalized splines; uniform convergence
UN Sustainable Development Goal Categories
Sources: Web Of Science, NC State University Libraries
Added: September 14, 2020

2020 journal article

Correlation models for monitoring fetal growth

STATISTICAL METHODS IN MEDICAL RESEARCH, 29(10), 2795–2813.

By: Y. Feng n, L. Xiao n, C. Li n, S. Chen n & E. Ohuma*

author keywords: Fetal health; longitudinal study; correlation; reference chart
MeSH headings : Female; Femur / diagnostic imaging; Fetal Development; Gestational Age; Humans; Longitudinal Studies; Pregnancy; Ultrasonography, Prenatal
TL;DR: Using data from the Fetal Growth Longitudinal Study of the INTERGROWTH-21st project, the longitudinal dependence of fetal head circumference, biparietal diameter, occipito-frontal diameter, abdominal circumference, and femur length is modelled using a two-stage approach. (via Semantic Scholar)
UN Sustainable Development Goal Categories
5. Gender Equality (Web of Science)
Sources: Web Of Science, NC State University Libraries
Added: April 20, 2020

2020 journal article

Fast covariance estimation for multivariate sparse functional data

STAT, 9(1).

By: C. Li n, L. Xiao n & S. Luo*

author keywords: bivariate smoothing; covariance function; functional principal component analysis; longitudinal data; multivariate functional data; prediction
TL;DR: A fast algorithm for selecting the smoothing parameters in covariance smoothing using leave‐one‐subject‐out cross‐validation is derived and applied to an Alzheimer's disease study with multiple longitudinal outcomes. (via Semantic Scholar)
Sources: Web Of Science, NC State University Libraries
Added: March 1, 2021

2020 journal article

Uniform convergence of penalized splines

STAT, 9(1).

By: L. Xiao n & Z. Nan*

author keywords: nonparametric regression; penalized splines; rate optimality; uniform convergence
UN Sustainable Development Goal Categories
Sources: Web Of Science, NC State University Libraries
Added: March 1, 2021

2019 journal article

A smoothing-based goodness-of-fit test of covariance for functional data

BIOMETRICS, 75(2), 562–571.

By: S. Chen n, L. Xiao n & A. Staicu n

author keywords: functional data analysis; Functional principal components analysis; hypothesis testing; linear mixed effects models; longitudinal data analysis
MeSH headings : Analysis of Variance; Computer Simulation; Data Interpretation, Statistical; Humans; Longitudinal Studies; Models, Statistical
TL;DR: A goodness‐of‐fit test for comparing parametric covariance functions against general nonparametric alternatives for both irregularly observed longitudinal data and densely observed functional data is proposed. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Sources: Web Of Science, NC State University Libraries, ORCID
Added: September 23, 2019

2019 journal article

Asymptotic theory of penalized splines

ELECTRONIC JOURNAL OF STATISTICS, 13(1), 747–794.

By: L. Xiao*

author keywords: Nonparametric regression; penalized splines; L-infinity convergence; L-2 convergence; local asymptotics; rate optimality
UN Sustainable Development Goal Categories
16. Peace, Justice and Strong Institutions (OpenAlex)
Sources: Web Of Science, ORCID, NC State University Libraries
Added: May 13, 2019

2019 journal article

Optimal design for classification of functional data

Canadian Journal of Statistics, 12.

By: C. Li n & L. Xiao n

author keywords: Covariance function; linear discriminant analysis; longitudinal data
TL;DR: The goal is to select sampling time points so that functional data observed at these time points can be classified accurately and the design objectives are formulated as explicit functions of the sampling points. (via Semantic Scholar)
UN Sustainable Development Goal Categories
10. Reduced Inequalities (OpenAlex)
Source: ORCID
Added: January 15, 2020

2019 journal article

Using data from multiple studies to develop a child growth correlation matrix

STATISTICS IN MEDICINE, 38(19), 3540–3554.

By: C. Anderson*, L. Xiao n & W. Checkley*

author keywords: child health; correlation; growth; SDS
MeSH headings : Body Height / physiology; Body Weight / physiology; Child; Child Development / physiology; Child, Preschool; Female; Growth / physiology; Growth Charts; Humans; Longitudinal Studies; Male; Meta-Analysis as Topic
TL;DR: This paper uses data from multiple longitudinal growth studies to construct a common correlation matrix that can be used in estimation and prediction of child growth, and proposes a novel 2‐stage approach. (via Semantic Scholar)
UN Sustainable Development Goal Categories
1. No Poverty (Web of Science)
2. Zero Hunger (Web of Science)
Sources: Web Of Science, NC State University Libraries, ORCID
Added: August 5, 2019

2018 journal article

A joint design for functional data with application to scheduling ultrasound scans

COMPUTATIONAL STATISTICS & DATA ANALYSIS, 122, 101–114.

By: S. Park*, L. Xiao n, J. Willbur*, A. Staicu n & N. Jumbe*

author keywords: Covariance function; Functional data analysis; Fetal growth; Longitudinal data; Prediction
TL;DR: A joint design for sampling functional data is proposed to achieve optimal prediction of both functional data and a scalar outcome and is formulated using an optimization criterion and implemented in a pilot study. (via Semantic Scholar)
Sources: Web Of Science, ORCID, NC State University Libraries
Added: August 6, 2018

2018 journal article

Asymptotics of bivariate penalised splines

Journal of Nonparametric Statistics, 31(2), 289–314.

By: L. Xiao n

author keywords: B-splines; P-splines; regression spline; smoothing; tensor product splines
UN Sustainable Development Goal Categories
Sources: ORCID, Crossref, NC State University Libraries
Added: January 15, 2020

2018 journal article

Dynamic prediction in functional concurrent regression with an application to child growth

STATISTICS IN MEDICINE, 37(8), 1376–1388.

author keywords: covariance function; face; fPCA; longitudinal data; mixed effects; penalized splines; sparse functional data
MeSH headings : Anthropometry; Body Height; Body Weight; Child Development; Child, Preschool; Computer Simulation; Data Interpretation, Statistical; Female; Forecasting / methods; Growth; Growth Charts; Humans; Infant; Infant, Newborn; Male; Peru; Regression Analysis
TL;DR: A dynamic functional concurrent regression model is proposed to handle the case where both the functional response and the functional predictors are irregularly measured, and shows that it provides more accurate estimation and inference than existing methods. (via Semantic Scholar)
Sources: Web Of Science, ORCID, NC State University Libraries
Added: August 6, 2018

2018 journal article

Fast covariance estimation for sparse functional data

STATISTICS AND COMPUTING, 28(3), 511–522.

By: L. Xiao n, C. Li n, W. Checkley* & C. Crainiceanu*

author keywords: Bivariate smoothing; FACEs; fPCA
TL;DR: The proposed method is a bivariate spline smoother that is designed for covariance smoothing and can be used for sparse functional or longitudinal data and compares favorably against several commonly used methods. (via Semantic Scholar)
Sources: Web Of Science, ORCID, NC State University Libraries
Added: August 6, 2018

2018 article

Fast covariance estimation for sparse functional data (vol 28, pg 511, 2017)

Xiao, L., Li, C., Checkley, W., & Crainiceanu, C. (2018, May). STATISTICS AND COMPUTING, Vol. 28, pp. 523–523.

By: L. Xiao n, C. Li n, W. Checkley* & C. Crainiceanu*

TL;DR: The article, “Fast covariance estimation for sparse functional data”, written by Luo Xiao, Cai Li, William Checkley and Ciprian Crainiceanu, was originally published electronically on the publisher’s Internet portal (currently SpringerLink) on 11 April 2017 without open access. (via Semantic Scholar)
Sources: Web Of Science, NC State University Libraries
Added: August 6, 2018

2018 journal article

Novel metrics for growth model selection

Emerging Themes in Epidemiology, 15.

By: M. Grigsby, J. Di, A. Leroux, V. Zipunnikov, L. Xiao, C. Crainiceanu, W. Checkley

Source: NC State University Libraries
Added: August 6, 2018

2018 personal communication

Total volume of physical activity: TAC, TLAC or TAC(lambda)

Varma, V. R., Dey, D., Leroux, A., Di, J., Urbanek, J., Xiao, L., & Zipunnikov, V. (2018, January).

author keywords: Physical activity
MeSH headings : Accelerometry; Exercise
TL;DR: The main issue is whether TLAC or TAC is the most appropriate measure of total volume of PA, and it is argued that 1) TAC most closely reflects moderate-to-vigorous PA (MVPA) while TLACmost closely reflects light-intensity PA (LiPA); and 2) Tac(λ) as a unifying measure to appropriately capture totalVolume of PA. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Sources: Web Of Science, ORCID, NC State University Libraries
Added: August 6, 2018

2017 journal article

AN ACTIVITY INDEX FOR RAW ACCELEROMETRY DATA AND ITS APPLICATION IN OLDER ADULTS

Innovation in Aging, 1(suppl_1), 1239–1239.

By: J. Bai*, C. Di*, L. Xiao n, K. Evenson*, A. LaCroix*, C. Crainiceanu*, D. Buchner*

Source: ORCID
Added: January 15, 2020

2017 journal article

Re-evaluating the effect of age on physical activity over the lifespan

PREVENTIVE MEDICINE, 101, 102–108.

author keywords: Accelerometer; Diurnal; Lifespan; NHANES; Physical activity; Sex differences; Gender
MeSH headings : Adolescent; Aged; Aging / physiology; Cross-Sectional Studies; Exercise; Female; Humans; Male; Nutrition Surveys; Sedentary Behavior; Sex Factors
TL;DR: It is found that from childhood to adolescence across sex, PA is sharply lower by age partially due to a later initiation of morning PA, and males compared to females have an earlier lowering in PA by age at midlife and lower total PA, higher sedentary behavior, and lower light intensity PA in older adulthood. (via Semantic Scholar)
UN Sustainable Development Goal Categories
2. Zero Hunger (OpenAlex)
Sources: Web Of Science, ORCID, NC State University Libraries
Added: August 6, 2018

2017 journal article

Simple fixed-effects inference for complex functional models

Biostatistics, 19(2), 137–152.

By: S. Park n, A. Staicu n, L. Xiao n & C. Crainiceanu*

author keywords: Bootstrap/resampling; Functional data; Measurement error; Smoothing and nonparametric regression
MeSH headings : Accelerometry / statistics & numerical data; Aged; Aged, 80 and over; Aging / physiology; Baltimore; Data Interpretation, Statistical; Exercise / physiology; Female; Humans; Longitudinal Studies; Middle Aged; Models, Statistical
TL;DR: Simple inferential approaches for the fixed effects in complex functional mixed effects models are proposed and motivated by and applied to the Baltimore Longitudinal Study of Aging, though they are applicable to other studies that collect correlated functional data. (via Semantic Scholar)
Sources: Web Of Science, ORCID, NC State University Libraries, Crossref
Added: August 6, 2018

2017 journal article

Two-way principal component analysis for matrix-variate data, with an application to functional magnetic resonance imaging data

Biostatistics (Oxford, England), 18(2), 214–229.

By: L. Huang, P. Reiss, L. Xiao, V. Zipunnikov, M. Lindquist & C. Crainiceanu

Source: NC State University Libraries
Added: August 6, 2018

2016 journal article

An Activity Index for Raw Accelerometry Data and Its Comparison with Other Activity Metrics

PLOS ONE, 11(8), 1–14.

MeSH headings : Accelerometry / instrumentation; Accelerometry / methods; Accelerometry / standards; Aged; Aged, 80 and over; Energy Metabolism; Exercise; Female; Humans; Middle Aged; ROC Curve; Software
TL;DR: The proposed physical activity index (AI) provides a novel and transparent way to summarize densely sampled raw accelerometry data, and may serve as an alternative to AC. (via Semantic Scholar)
Sources: ORCID, NC State University Libraries, NC State University Libraries
Added: August 6, 2018

2016 journal article

CollocInfer: Collocation Inference in Differential Equation Models

Journal of Statistical Software, 75(2).

By: G. Hooker*, J. Ramsay* & L. Xiao n

author keywords: differential equation; collocation; profiled estimation; smoothing
TL;DR: The implementation and use of the CollocInfer package in R for smoothing-based estimation of continuous-time nonlinear dynamic systems and an interface to the fda package is included. (via Semantic Scholar)
Sources: ORCID, NC State University Libraries, NC State University Libraries
Added: August 6, 2018

2016 journal article

Convex Banding of the Covariance Matrix

Journal of the American Statistical Association, 111(514), 834–845.

By: J. Bien, F. Bunea & L. Xiao*

author keywords: Adaptive; Hierarchical group lasso; High-dimensional; Structured sparsity
TL;DR: A new sparse estimator of the covariance matrix for high-dimensional models in which the variables have a known ordering and is minimax rate adaptive in Frobenius and operator norms, up to log factors, over commonly studied classes of covariance matrices, and over more general classes. (via Semantic Scholar)
UN Sustainable Development Goal Categories
10. Reduced Inequalities (OpenAlex)
Sources: ORCID, Crossref, NC State University Libraries
Added: January 15, 2020

2016 journal article

Fast covariance estimation for high-dimensional functional data

Statistics and Computing, 26(1-2), 409–421.

By: L. Xiao*, V. Zipunnikov*, D. Ruppert* & C. Crainiceanu*

author keywords: FACE; fPCA; Penalized splines; Sandwich smoother; Smoothing; Singular value decomposition
TL;DR: A fast implementation of the sandwich smoother for covariance smoothing and a two-step procedure that first obtains the singular value decomposition of the data matrix and then smoothes the eigenvectors are introduced. (via Semantic Scholar)
Sources: Crossref, NC State University Libraries, ORCID
Added: January 15, 2020

2016 journal article

Movement prediction using accelerometers in a human population

BIOMETRICS, 72(2), 513–524.

author keywords: Accelerometer; Activity type; Movelets; Prediction
MeSH headings : Accelerometry / statistics & numerical data; Activities of Daily Living; Forecasting; Humans; Movement / physiology; Posture; Supervised Machine Learning
TL;DR: Analysis of statistical methods for predicting the types of human activity at sub‐second resolution using triaxial accelerometry data indicates that prediction of activity types for data collected during natural activities of daily living may actually be possible. (via Semantic Scholar)
Sources: Web Of Science, ORCID, NC State University Libraries
Added: August 6, 2018

2016 journal article

Two-way principal component analysis for matrix-variate data, with an application to functional magnetic resonance imaging data

Biostatistics, 8, kxw040.

By: L. Huang*, P. Reiss, L. Xiao n, V. Zipunnikov*, M. Lindquist* & C. Crainiceanu*

author keywords: fMRI; Latent process modeling; Matrix-variate; Principal component analysis; Separability
MeSH headings : Brain Mapping / methods; Humans; Magnetic Resonance Imaging / methods; Principal Component Analysis
TL;DR: This work introduces a class of separable processes using explicit latent process modeling to account for the size and two-way structure of the data, and extends principal component analysis to achieve dimensionality reduction at the individual level. (via Semantic Scholar)
Source: ORCID
Added: January 15, 2020

2015 journal article

On tests of activation map dimensionality for fMRI-based studies of learning

Frontiers in Neuroscience, 9.

By: J. Yang*, L. Shmuelof*, L. Xiao*, J. Krakauer* & B. Caffo*

author keywords: canonical variates analysis; cognitive learning; BOLD fMRI; statistical parametric mapping; interaction test
TL;DR: The development of the framework, a large scale simulation study, and the subsequent application to a study of motor learning in healthy adults found that the study of linear dimensionality is able to capture learning effects. (via Semantic Scholar)
Source: ORCID
Added: January 15, 2020

2015 journal article

On the sample covariance matrix estimator of reduced effective rank population matrices, with applications to fPCA

Bernoulli, 21(2), 1200–1230.

By: F. Bunea* & L. Xiao*

author keywords: covariance matrix; eigenvalue; eigenvector; fPCA; high dimensions; minimax rate; optimal rate of convergence; PCA; scree plot; sparsity
TL;DR: It is shown that identifying jumps in the empirical spectrum that consistently estimate jumped in the spectrum of $\Sigma$ is not necessarily informative for other goals, for instance for the selection of those sample eigenvalues and eigenvectors that are consistent estimates of their population counterparts. (via Semantic Scholar)
Source: ORCID
Added: January 15, 2020

2014 journal article

Bayesian Models for Multiple Outcomes in Domains With Application to the Seychelles Child Development Study

Journal of the American Statistical Association, 109(505), 1–10.

By: L. Xiao*, S. Thurston*, D. Ruppert*, T. Love* & P. Davidson*

author keywords: Bayesian variable selection; Latent variable model; Markov chain Monte Carlo; Methylmercury; Sparsity
Source: ORCID
Added: January 15, 2020

2014 journal article

Learning regulatory programs by threshold SVD regression

Proceedings of the National Academy of Sciences, 111(44), 15675–15680.

By: X. Ma, L. Xiao* & W. Wong*

author keywords: regulatory program; SVD; sparse; multivariate; regression
MeSH headings : Computer Simulation; Gene Expression Regulation, Neoplastic; Humans; MicroRNAs / biosynthesis; MicroRNAs / genetics; Models, Genetic; Neoplasms / genetics; Neoplasms / metabolism; RNA, Neoplasm / biosynthesis; RNA, Neoplasm / genetics
TL;DR: It is shown that by formulating the regulatory programs as hidden-intermediate nodes in a linear network, a sparsity-inducing modeling and inference approach is effective in extracting the regulatory relations among very high-dimensional responses and predictors, even when the sample size is much lower. (via Semantic Scholar)
Source: ORCID
Added: January 15, 2020

2014 journal article

Quantifying the lifetime circadian rhythm of physical activity: a covariate-dependent functional approach

Biostatistics, 16(2), 352–367.

author keywords: Accelerometer; Bivariate smoothing; Covariance; Sandwich smoother; Trivariate smoothing
MeSH headings : Accelerometry / statistics & numerical data; Adult; Aged; Aged, 80 and over; Aging / physiology; Circadian Rhythm / physiology; Female; Humans; Male; Middle Aged; Motor Activity / physiology; Principal Component Analysis; Sex Factors
TL;DR: A practical and very fast trivariate spline smoother is proposed to estimate covariate-dependent covariances and their spectra and several interesting, previously unknown, circadian patterns associated with human aging and gender are revealed. (via Semantic Scholar)
Source: ORCID
Added: January 15, 2020

2013 journal article

Fast bivariateP-splines: the sandwich smoother

Journal of the Royal Statistical Society: Series B (Statistical Methodology), 75(3), 577–599.

By: L. Xiao*, Y. Li* & D. Ruppert*

author keywords: Asymptotics; Bivariate smoothing; Covariance function; Generalized linear array model; Non-parametric regression; Penalized splines; Sandwich smoother; Thin plate splines
TL;DR: The sandwich smoother is orders of magnitude faster to compute than other bivariate spline smoothers, even when the latter are computed by using a fast generalized linear array model algorithm, and comparable with them in terms of mean integrated squared errors. (via Semantic Scholar)
Source: ORCID
Added: January 15, 2020

Employment

Updated: November 27th, 2017 22:41

2015 - present

North Carolina State University Raleigh, NC, US
Assistant Professor Department of Statistics

2012 - 2015

Johns Hopkins University Baltimore, MD, US
Postdoctoral Fellow Deparment of Biostatistics

Education

Updated: November 27th, 2017 22:38

2007 - 2012

Cornell University Ithaca, NY, US
PhD Department of Statistics

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