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Model-based clustering imposes a finite mixture modelling structure on data for clustering. Finite mixture models assume that the population is a convex combination of a finite number of densities, the distribution within each population is…

统计方法学 · 统计学 2017-10-09 Cristina Tortora , Paul D. McNicholas , Ryan P. Browne

This paper studies the distributed optimization problem under the influence of heavy-tailed gradient noises. Here, a heavy-tailed noise means that the noise does not necessarily satisfy the bounded variance assumption. Instead, it satisfies…

最优化与控制 · 数学 2025-05-12 Chao Sun , Huiming Zhang , Bo Chen , Li Yu

Long-tailed classification poses a challenge due to its heavy imbalance in class probabilities and tail-sensitivity risks with asymmetric misprediction costs. Recent attempts have used re-balancing loss and ensemble methods, but they are…

机器学习 · 计算机科学 2023-03-22 Bolian Li , Ruqi Zhang

We propose a novel Bayesian model selection technique on linear mixed-effects models to compare multiple treatments with a control. A fully Bayesian approach is implemented to estimate the marginal inclusion probabilities that provide a…

应用统计 · 统计学 2015-09-28 Lei Gong , James M. Flegal , Stephen R. Spindler , Patricia L. Mote

Modern risk modelling approaches deal with vectors of multiple components. The components could be, for example, returns of financial instruments or losses within an insurance portfolio concerning different lines of business. One of the…

概率论 · 数学 2021-05-12 Miriam Hägele , Jaakko Lehtomaa

Let $X_1, \ldots, X_n$ be some i.i.d. observations from a heavy tailed distribution $F$, i.e. such that the common distribution of the excesses over a high threshold $u_n$ can be approximated by a Generalized Pareto Distribution…

统计理论 · 数学 2010-08-23 Julien Worms , Rym Worms

In risk management, tail risks are of crucial importance. The assessment of risks should be carried out in accordance with the regulatory authority's requirement at high quantiles. In general, the underlying distribution function is…

风险管理 · 定量金融 2020-07-15 Ingo Hoffmann , Christoph J. Börner

We propose a flexible formulation of the multivariate non-central skew t (NCST) distribution, defined by scaling skew-normal random vectors with independent chi-squared variables. This construction extends the classical multivariate t…

统计方法学 · 统计学 2025-07-15 Abeer M. Hasan , Ying-Ju Chen

It has been shown that some macroeconomic time series, especially those where outliers could be present, can be well modelled using heavy tailed distributions for the noise components. Methods for deciding when and where heavy-tailed models…

统计理论 · 数学 2007-06-13 J. A. D. Aston

We propose the notion of sub-Weibull distributions, which are characterised by tails lighter than (or equally light as) the right tail of a Weibull distribution. This novel class generalises the sub-Gaussian and sub-Exponential families to…

统计理论 · 数学 2020-12-04 Mariia Vladimirova , Stephane Girard , Hien Nguyen , Julyan Arbel

Because of its mathematical tractability, the Gaussian mixture model holds a special place in the literature for clustering and classification. For all its benefits, however, the Gaussian mixture model poses problems when the data is skewed…

应用统计 · 统计学 2020-11-19 Michael P. B. Gallaugher , Paul D. McNicholas , Volodymyr Melnykov , Xuwen Zhu

We extend the construction principle of phase-type (PH) distributions to allow for inhomogeneous transition rates and show that this naturally leads to direct probabilistic descriptions of certain transformations of PH distributions. In…

概率论 · 数学 2019-07-01 Hansjörg Albrecher , Mogens Bladt

In clinical trials, studies often present longitudinal data or clustered data. These studies are commonly analyzed using linear mixed models (LMMs), usually considering Gaussian assumptions for random effect and error terms. Recently,…

统计方法学 · 统计学 2021-09-28 Fernanda L. Schumacher , Larissa A. Matos , Celso R. B. Cabral

Graphical models are ubiquitous tools to describe the interdependence between variables measured simultaneously such as large-scale gene or protein expression data. Gaussian graphical models (GGMs) are well-established tools for…

统计方法学 · 统计学 2020-01-09 Nilabja Guha , Veera Baladandayuthapani , Bani K. Mallick

For large model spaces, the potential entrapment of Markov chain Monte Carlo (MCMC) based methods with spike-and-slab priors poses significant challenges in posterior computation in regression models. On the other hand, maximum a posteriori…

统计方法学 · 统计学 2026-02-25 Shamriddha De , Joyee Ghosh

Risk assessment for rare events is essential for understanding systemic stability in complex systems. As rare events are typically highly correlated, it is important to study heavy-tailed multivariate distributions of the relevant…

统计金融 · 定量金融 2025-12-02 Efstratios Manolakis , Anton J. Heckens , Benjamin Köhler , Thomas Guhr

Clustering high-dimensional data is especially challenging when cluster distributions are heavy tailed and only approximately elliptical. Existing high-dimensional methods are largely built for Gaussian or other light-tailed models, whereas…

统计方法学 · 统计学 2026-05-12 Long Feng , Dan Zhuang

The Yule--Simon distribution has been out of the radar of the Bayesian community, so far. In this note, we propose an explicit Gibbs sampling scheme when a Gamma prior is chosen for the shape parameter. The performance of the algorithm is…

统计方法学 · 统计学 2017-07-04 Fabrizio Leisen , Luca Rossini , Cristiano Villa

We consider the task of heavy-tailed statistical estimation given streaming $p$-dimensional samples. This could also be viewed as stochastic optimization under heavy-tailed distributions, with an additional $O(p)$ space complexity…

机器学习 · 计算机科学 2022-02-28 Che-Ping Tsai , Adarsh Prasad , Sivaraman Balakrishnan , Pradeep Ravikumar

We introduce a mixture of generalized hyperbolic distributions as an alternative to the ubiquitous mixture of Gaussian distributions as well as their near relatives of which the mixture of multivariate t and skew-t distributions are…

统计方法学 · 统计学 2017-10-09 Ryan P. Browne , Paul D. McNicholas