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Probability density estimation from observed data constitutes a central task in statistics. In this brief, we focus on the problem of estimating the copula density associated to any observed data, as it fully describes the dependence…

Machine Learning · Computer Science 2025-07-09 Nunzio A. Letizia , Nicola Novello , Andrea M. Tonello

Bi-factor and second-order models based on copulas are proposed for item response data, where the items can be split into non-overlapping groups such that there is a homogeneous dependence within each group. Our general models include the…

Methodology · Statistics 2021-02-23 Sayed H. Kadhem , Aristidis K. Nikoloulopoulos

We consider functional linear regression models where functional outcomes are associated with scalar predictors by coefficient functions with shape constraints, such as monotonicity and convexity, that apply to sub-domains of interest. To…

Methodology · Statistics 2025-05-09 Kyunghee Han , Yeonjoo Park , Soo-Young Kim

We propose a procedure for imputing missing values of time-dependent covariates in a survival model using fully conditional specification. Specifically, we focus on imputing missing values of a longitudinal marker in joint modeling of the…

Methodology · Statistics 2024-03-29 Havi Murad , Nirit Agay , Rachel Dankner

Continuous proportions measured on the same experimental unit often pose two challenges: interior outliers that inflate variance beyond the beta ceiling and residual dependence that invalidates independent-margin models. We introduce a…

Methodology · Statistics 2025-11-14 Divan A. Burger , Janet van Niekerk , Peter C. le Roux , Morgan J. Raath-Krüger

Copulas allow to learn marginal distributions separately from the multivariate dependence structure (copula) that links them together into a density function. Vine factorizations ease the learning of high-dimensional copulas by constructing…

Methodology · Statistics 2013-02-19 David Lopez-Paz , José Miguel Hernández-Lobato , Zoubin Ghahramani

Several studies on heritability in twins aim at understanding the different contribution of environmental and genetic factors to specific traits. Considering the National Merit Twin Study, our purpose is to correctly analyse the influence…

Methodology · Statistics 2017-07-04 Luciana Dalla Valle , Fabrizio Leisen , Luca Rossini

The majority of model-based clustering techniques is based on multivariate Normal models and their variants. In this paper copulas are used for the construction of flexible families of models for clustering applications. The use of copulas…

Methodology · Statistics 2018-02-16 Ioannis Kosmidis , Dimitris Karlis

In this paper we build a joint model which can accommodate for binary, ordinal and continuous responses, by assuming that the errors of the continuous variables and the errors underlying the ordinal and binary outcomes follow a multivariate…

Methodology · Statistics 2024-11-06 Laura Vana-Gür , Rainer Hirk

Observational studies of treatment effects require adjustment for confounding variables. However, causal inference methods typically cannot deliver perfect adjustment on all measured baseline variables, and there is often ambiguity about…

Methodology · Statistics 2024-02-16 Lauren D. Liao , Yeyi Zhu , Amanda L. Ngo , Rana F. Chehab , Samuel D. Pimentel

Multivariate bounded discrete data arises in many fields. In the setting of dementia studies, such data is collected when individuals complete neuropsychological tests. We outline a modeling and inference procedure that can model the joint…

Methodology · Statistics 2026-02-10 Daniel Suen , Yen-Chi Chen

Joint models for longitudinal and time-to-event data have seen many developments in recent years. Though spatial joint models are still rare and the traditional proportional hazards formulation of the time-to-event part of the model is…

Methodology · Statistics 2024-06-25 Anja Rappl , Thomas Kneib , Stefan Lang , Elisabeth Bergherr

Intensive longitudinal biomarker data are increasingly common in scientific studies that seek temporally granular understanding of the role of behavioral and physiological factors in relation to outcomes of interest. Intensive longitudinal…

Methodology · Statistics 2024-01-17 Mingyan Yu , Zhenke Wu , Margaret Hicken , Michael R. Elliott

There has been a lot of work fitting Ising models to multivariate binary data in order to understand the conditional dependency relationships between the variables. However, additional covariates are frequently recorded together with the…

Machine Learning · Statistics 2012-09-28 Jie Cheng , Elizaveta Levina , Pei Wang , Ji Zhu

We propose a single neural probabilistic model based on variational autoencoder that can be conditioned on an arbitrary subset of observed features and then sample the remaining features in "one shot". The features may be both real-valued…

Machine Learning · Statistics 2019-07-01 Oleg Ivanov , Michael Figurnov , Dmitry Vetrov

Classical models for multivariate or spatial extremes are mainly based upon the asymptotically justified max-stable or generalized Pareto processes. These models are suitable when asymptotic dependence is present, i.e., the joint tail…

Methodology · Statistics 2021-05-13 Zhongwei Zhang , Raphaël Huser , Thomas Opitz , Jennifer L. Wadsworth

In this paper, we propose a novel approach for estimating Archimedean copula generators in a conditional setting, incorporating endogenous variables. Our method allows for the evaluation of the impact of the different levels of covariates…

Methodology · Statistics 2024-04-12 Marie Michaelides , Hélène Cossette , Mathieu Pigeon

The development of statistical approaches for the joint modelling of the temporal changes of imaging, biochemical, and clinical biomarkers is of paramount importance for improving the understanding of neurodegenerative disorders, and for…

Applications · Statistics 2018-02-16 Marco Lorenzi , Maurizio Filippone , Daniel C. Alexander , Sebastien Ourselin

We present a Bayesian approach for modeling multivariate, dependent functional data. To account for the three dominant structural features in the data--functional, time dependent, and multivariate components--we extend hierarchical dynamic…

Methodology · Statistics 2019-07-02 Daniel R. Kowal , David S. Matteson , David Ruppert

This paper presents a method for fitting a copula-driven generalized linear mixed models. For added flexibility, the skew-normal copula is adopted for fitting. The correlation matrix of the skew-normal copula is used to capture the…

Methodology · Statistics 2017-08-01 Kalyan Das , Mohamad Elmasri , Arusharka Sen