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We give an explicit algorithm and source code for constructing risk models based on machine learning techniques. The resultant covariance matrices are not factor models. Based on empirical backtests, we compare the performance of these…

Portfolio Management · Quantitative Finance 2019-04-10 Zura Kakushadze , Willie Yu

Structural equation models are commonly used to capture the relationship between sets of observed and unobservable variables. Traditionally these models are fitted using frequentist approaches but recently researchers and practitioners have…

Methodology · Statistics 2023-02-22 Khue-Dung Dang , Luca Maestrini

Generative models are increasingly deployed as substitutes for real data in downstream scientific workflows, yet standard evaluation criteria remain focused on marginal distribution matching. We argue that this represents a fundamental gap:…

Machine Learning · Statistics 2026-05-19 Nazia Riasat

Estimation of Markov Random Field and covariance models from high-dimensional data represents a canonical problem that has received a lot of attention in the literature. A key assumption, widely employed, is that of {\em sparsity} of the…

Optimization and Control · Mathematics 2018-05-16 Davoud Ataee Tarzanagh , George Michailidis

In observational studies, treatment may be adapted to covariates at several times without a fixed protocol, in continuous time. Treatment influences covariates, which influence treatment, which influences covariates, and so on. Then even…

Statistics Theory · Mathematics 2015-09-02 Judith J. Lok

Cumulant mapping employs a statistical reconstruction of the whole by sampling its parts. The theory developed in this work formalises and extends ad hoc methods of `multi-fold' or `multi-dimensional' covariance mapping. Explicit formulae…

Data Analysis, Statistics and Probability · Physics 2023-11-06 Leszek J. Frasinski

This work explores new classes of nonstationary stochastic sequences associated with polynomial hypergroups. Their covariance structures are analyzed through positive definite kernels and corresponding Hilbert spaces. Novel consistent…

Functional Analysis · Mathematics 2024-11-27 Volker Hösel

Covariance estimation is ubiquitous in functional data analysis. Yet, the case of functional observations over multidimensional domains introduces computational and statistical challenges, rendering the standard methods effectively…

Methodology · Statistics 2022-11-02 Soham Sarkar , Victor M. Panaretos

The least-squares support vector machine is a frequently used kernel method for non-linear regression and classification tasks. Here we discuss several approximation algorithms for the least-squares support vector machine classifier. The…

Machine Learning · Computer Science 2017-03-24 M. Andrecut

Deep learning has enjoyed tremendous success in a variety of applications but its application to quantile regressions remains scarce. A major advantage of the deep learning approach is its flexibility to model complex data in a more…

Statistics Theory · Mathematics 2021-06-14 Qixian Zhong , Jane-Ling Wang

Quantile regression permits describing how quantiles of a scalar response variable depend on a set of predictors. Because a unique definition of multivariate quantiles is lacking, extending quantile regression to multivariate responses is…

Methodology · Statistics 2021-04-22 Silvia Columbu , Paolo Frumento , Matteo Bottai

Multivariate extreme-value analysis is concerned with the extremes in a multivariate random sample, that is, points of which at least some components have exceptionally large values. Mathematical theory suggests the use of max-stable models…

Probability · Mathematics 2012-04-03 Johan Segers

The basic Kriging's model assumes a Gaussian distribution with stationary mean and stationary variance. In such a setting, the joint distribution of the spatial process is characterized by the common variance and the correlation matrix or,…

Statistics Theory · Mathematics 2016-12-12 Giovanni Pistone , Grazia Vicario

We develop a model-based method for evaluating heterogeneity among several p x p covariance matrices in the large p, small n setting. This is done by assuming a spiked covariance model for each group and sharing information about the space…

Methodology · Statistics 2019-10-22 Alexander Franks , Peter Hoff

Beta regression models provide an adequate approach for modeling continuous outcomes limited to the interval (0,1). This paper deals with an extension of beta regression models that allow for explanatory variables to be measured with error.…

Methodology · Statistics 2013-04-11 Jalmar M. F. Carrasco , Silvia L. P. Ferrari , Reinaldo B. Arellano-Valle

Motivated by recent work studying massive imaging data in the neuroimaging literature, we propose multivariate varying coefficient models (MVCM) for modeling the relation between multiple functional responses and a set of covariates. We…

Statistics Theory · Mathematics 2013-02-19 Hongtu Zhu , Runze Li , Linglong Kong

The use of covariance kernels is ubiquitous in the field of spatial statistics. Kernels allow data to be mapped into high-dimensional feature spaces and can thus extend simple linear additive methods to nonlinear methods with higher order…

Machine Learning · Statistics 2017-11-16 Jean-Francois Ton , Seth Flaxman , Dino Sejdinovic , Samir Bhatt

Machine learning (ML) applications have automated numerous real-life tasks, improving both private and public life. However, the black-box nature of many state-of-the-art models poses the challenge of model verification; how can one be sure…

Machine Learning · Computer Science 2022-01-19 Ioannis Papantonis , Vaishak Belle

Estimating the conditional quantile of the interested variable with respect to changes in the covariates is frequent in many economical applications as it can offer a comprehensive insight. In this paper, we propose a novel semiparametric…

Statistics Theory · Mathematics 2022-06-08 Jing Lv

The multivariate linear regression model is an important tool for investigating relationships between several response variables and several predictor variables. The primary interest is in inference about the unknown regression coefficient…

Statistics Theory · Mathematics 2017-09-13 Daniel J. Eck