Motivated by the modeling of liquidity risk in fund management in a dynamic setting, we propose and investigate a class of time series models with generalized Pareto marginals: the autoregressive generalized Pareto process (ARGP), a modified ARGP (MARGP) and a thresholded ARGP (TARGP). These models are able to capture key data features apparent in fund liquidity data and reflect the underlying phenomena via easily interpreted, low-dimensional model parameters. We establish stationarity and ergodicity, provide a link to the class of shot-noise processes, and determine the associated interarrival distributions for exceedances. Moreover, we provide estimators for all relevant model parameters and establish consistency and asymptotic normality for all estimators (except the threshold parameter, which as usual must be dealt with separately). Finally, we illustrate our approach using real-world fund redemption data, and we discuss the goodness-of-fit of the estimated models.
Testing approximate normality of an estimator using the estimated MSE and bias with an application to the shape parameter of the generalized Pareto distribution
Testing for a δ-neighborhood of a generalized Pareto copula
一个多元分布函数F在一个极值分布的最大吸引区域中当且仅当这对于对应于F的Copula和它的单变量边缘是真的。Aulbach et al.（2012 a）证明了一个copula满足极值条件当且仅当它尾等价于广义Pareto copula（GPC）。本文提出了一种任意维的卡方拟合优度检验方法，用于检验copula是否在广义预测控制的某个邻域内。该检验也可以应用于随机过程，检验相应的Copula过程是否接近广义Pareto过程。由于所提出的检验的p值对适当选择某个阈值高度敏感，因此我们还提供了一个图形工具，可以更轻松地做出是否拒绝假设的决定。
This paper reviews generalized Pareto copulas (GPC), which turn out to be a key to multivariate extreme value theory. Any GPC can be represented in an easy analytic way using a particular type of norm on $\mathbb{R}^d$, called $D$-norm. The characteristic property of a GPC is its exceedance stability. GPC might help to end the debate: What is a multivariate generalized Pareto distribution? We present an easy way how to simulate data from an arbitrary GPC and, thus, from an arbitrary generalized Pareto distribution. As an application we derive nonparametric estimates of the probability that a r…
After Pareto distribution has been validated for sea clutter returns in varied scenarios, some heuristics of adaptive-thresholding appeared in the literature for constant false alarm rate (CFAR) criteria. These schemes used the same adaptive-thresholding form that was originally derived for detecting Swerling-I (exponential) target in exponentially distributed clutter. Statistical procedures obtained under such idealistic assumptions would affect the detection performance when applied to newer target and clutter models, esp. heavy tail distributions like Pareto. Further, in addition to the sea…
Local asymptotic normality in δ-neighborhoods of standard generalized Pareto processes
De Haan和Pereira（2006）提供了平稳性情况下的空间极值模型，该模型仅依赖于一个参数β > 0来衡量尾部依赖性，他们为该参数提出了不同的估计量。Falk（2011）通过建立高于高多元阈值的相应点过程的局部渐近正态性（LAN）对该框架进行了补充，特别是产生渐近有效估计。在这些论文中研究的估计量是基于点t1，.的有限集，td，在此进行观察。我们推广这种方法的背景下，功能极值理论（EVT）。这个更一般的框架允许在某个空间参数空间上进行估计，即，点t1，.的有限集在[a，b]中，td被t代替。特别地，我们基于C[0，1]中iid过程的样本中超过给定门限函数的过程，得到了β的有效估计.
In this paper, we study the multi-objective bandits (MOB) problem, where a learner repeatedly selects one arm to play and then receives a reward vector consisting of multiple objectives. MOB has found many real-world applications as varied as online recommendation and network routing. On the other hand, these applications typically contain contextual information that can guide the learning process which, however, is ignored by most of existing work. To utilize this information, we associate each arm with a context vector and assume the reward follows the generalized linear model (GLM). We adop…
We revisit multivariate extreme value theory modeling by emphasizing multivariate regular variations and the multivariate Breiman Lemma. This allows us to recover in a simple framework the most popular multivariate extreme value distributions, such as the logistic, negative logistic, Dirichlet, extremal-$t$ and Hüsler-Reiss models. In a second part of the paper, we focus on the Hüsler-Reiss Pareto model and its surprising exponential family property. After a thorough study of this exponential family structure, we focus on maximum likelihood estimation. We also consider the generalized Hüsler-R…
A coupling method is developed for univariate extreme value theory , providing an alternative to the use of the tail empirical/quantile processes. Emphasizing the Peak-over-Threshold approach that approximates the distribution above high threshold by the Generalized Pareto distribution, we compare the empirical distribution of exceedances and the empirical distribution associated to the limit Generalized Pareto model and provide sharp bounds for their Wasser-stein distance in the second order Wasserstein space. As an application , we recover standard results on the asymptotic behavior of the H…
Institute for AI & Fundamental Interactions（人工智能与基础交互研究所）；Theiss Research
We present an improved method for symbolic regression that seeks to fit data to formulas that are Pareto-optimal, in the sense of having the best accuracy for a given complexity. It improves on the previous state-of-the-art by typically being orders of magnitude more robust toward noise and bad data, and also by discovering many formulas that stumped previous methods. We develop a method for discovering generalized symmetries (arbitrary modularity in the computational graph of a formula) from gradient properties of a neural network fit. We use normalizing flows to generalize our symbolic regre…
Renewable sources of energy such as wind power have become a sustainable alternative to fossil fuel-based energy. However, the uncertainty and fluctuation of the wind speed derived from its intermittent nature bring a great threat to the wind power production stability, and to the wind turbines themselves. Lately, much work has been done on developing models to forecast average wind speed values, yet surprisingly little has focused on proposing models to accurately forecast extreme wind speeds, which can damage the turbines. In this work, we develop a flexible spliced Gamma-Generalized Pareto …
Likelihood-Free Inference for Multivariate Generalized Pareto Models
LSCE（气候与环境科学实验室）；ESSEC Business School, IDO Dep. and CREAR（欧洲高等商业学院，创新与决策系及CREAR）；Université Paris Saclay & ESSEC Business School CREAR（巴黎萨克雷大学及欧洲高等商业学院CREAR）；Laboratoire des Sciences du Climat et de l’Environnement, CNRS-CEA-UVSQ-IPSL（气候与环境科学实验室，CNRS-CEA-UVSQ-IPSL）
In recent years several attempts have been made to extend tail modelling towards the modal part of the data. Frigessi et al. (2002) introduced dynamic mixtures of two components with a weight function π = π(x) smoothly connecting the bulk and the tail of the distribution. Recently, Naveau et al. (2016) reviewed this topic, and, continuing on the work by Papastathopoulos and Tawn (2013), proposed a statistical model which is in compliance with extreme value theory and allows for a smooth transition between the modal and tail part. Incorporating second order rates of convergence for distribution…
When assessing the impact of extreme events, it is often not just a single component, but the combined behaviour of several components which is important. Statistical modelling using multivariate generalized Pareto (GP) distributions constitutes the multivariate analogue of univariate peaks over thresholds modelling, which is widely used in finance and engineering. We develop general methods for construction of multivariate GP distributions and use them to create a variety of new statistical models. A censored likelihood procedure is proposed to make inference on these models, together with a …
Extreme quantile regression provides estimates of conditional quantiles outside the range of the data. Classical quantile regression performs poorly in such cases since data in the tail region are too scarce. Extreme value theory is used for extrapolation beyond the range of observed values and estimation of conditional extreme quantiles. Based on the peaks-over-threshold approach, the conditional distribution above a high threshold is approximated by a generalized Pareto distribution with covariate dependent parameters. We propose a gradient boosting procedure to estimate a conditional genera…
Accuracy estimation of neural networks by extreme value theory
Department of Mathematics, Ludwig-Maximilians Universität（数学系，路易斯-马克西米利安大学）；Stuttgart Center for Simulation Science (SC SimTech) and Institute for Stochastics and Applications（斯图加特模拟科学中心（SC SimTech）和应用概率研究所）；University of Stuttgart（斯图加特大学）
In this survey we present an extensive research of the vast literature about the Generalized Lambda Distribution (GLD) and propose a hurdle, or two-way, model whose associated distribution is the GLD in order to meet the demand for a highly flexible model of heavy-tailed data with excess of zeros. We apply the developed models to a dataset consisting of yearly healthcare expenses, a typical example of heavy-tailed data with excess of zeros. The fitted models are compared with models based on the Generalised Pareto Distribution and it is established that the GLD models perform best.
