Anisotropic local constant smoothing for change-point regression function estimation
John R. J. Thompson, W. John Braun
备注:
30 pages, 12 figures. Parts of this Original Manuscript are in an article published by Taylor & Francis in the Journal of Applied Statistics on April 20th 2024, available at https://doi.org/10.1080/02664763.2024.2352759
Understanding forest fire spread in any region of Canada is critical to promoting forest health, and protecting human life and infrastructure. Quantifying fire spread from noisy images, where regions of a fire are separated by change-point boundaries, is critical to faithfully estimating fire spread rates. In this research, we develop a statistically consistent smooth estimator that allows us to denoise fire spread imagery from micro-fire experiments. We develop an anisotropic smoothing method for change-point data that uses estimates of the underlying data generating process to inform smoothing. We show that the anisotropic local constant regression estimator is consistent with convergence rate $O\left(n^{-1/{(q+2)}}\right)$. We demonstrate its effectiveness on simulated one- and two-dimensional change-point data and fire spread imagery from micro-fire experiments.
Starting with the Fourier integral theorem, we present natural Monte Carlo estimators of multivariate functions including densities, mixing densities, transition densities, regression functions, and the search for modes of multivariate density functions (modal regression). Rates of convergence are established and, in many cases, provide superior rates to current standard estimators such as those based on kernels, including kernel density estimators and kernel regression functions. Numerical illustrations are presented.
$\ell_1$-penalized quantile regression is widely used for analyzing high-dimensional data with heterogeneity. It is now recognized that the $\ell_1$-penalty introduces non-negligible estimation bias, while a proper use of concave regularization may lead to estimators with refined convergence rates and oracle properties as the signal strengthens. Although folded concave penalized $M$-estimation with strongly convex loss functions have been well studied, the extant literature on quantile regression is relatively silent. The main difficulty is that the quantile loss is piecewise linear: it is non…
We introduce a highly efficient fully Bayesian approach for anisotropic multidimensional smoothing. The main challenge in this context is the Markov chain Monte Carlo update of the smoothing parameters as their full conditional posterior comprises a pseudo-determinant that appears to be intractable at first sight. As a consequence, most existing implementations are computationally feasible only for the estimation of two-dimensional tensor product smooths, which is, however, too restrictive for many applications. In this paper, we break this barrier and derive closed-form expressions for the lo…
Censored broken adaptive ridge rank regression via induced smoothing
School of Mathematics, Statistics and Data Science, Sungshin Women’s University(成均馆大学数学、统计与数据科学学院);Sungshin Women’s University(诚信女子大学);Department of Biostatistics, Virginia Commonwealth University(弗吉尼亚联邦大学生物统计系);Virginia Commonwealth University(弗吉尼亚联邦大学);Center for Data Science, Sungshin Women’s University(诚信女子大学数据科学中心)
This paper studies the estimation and inference for the isotonic regression at the boundary point, an object that is particularly interesting and required in the analysis of monotone regression discontinuity designs. We show that the isotonic regression is inconsistent in this setting and derive the asymptotic distributions of boundary corrected estimators. Interestingly, the boundary corrected estimators can be bootstrapped without subsampling or additional nonparametric smoothing which is not the case for the interior point. The Monte Carlo experiments indicate that shape restrictions can im…
Efficient Estimation in Single Index Models through Smoothing splines
本文研究了具有未知光滑连接函数的单指标回归模型的估计和推断问题。与使用核函数或回归样条函数的标准方法相比,我们使用平滑样条函数来估计平滑连接函数。在独立同分布(independent and identical distributed,i.i.d.)~(?)的情况下,我们给出了一种计算参数和非参数分量的惩罚最小二乘估计(penalized least squares estimator,PLSE)的方法。数据我们证明的一致性,并找到估计的收敛速度。在较弱的假设下建立了参数分量的渐近正态性,并证明了参数分量在同方差误差下的渐近有效性。有限样本模拟证实了我们的渐近理论。我们还分析了汽车里程数据集和臭氧浓度数据集。最后,研究了偏最小二乘估计的可辨识性和存在性。
Turku School of Economics, University of Turku(图尔库经济学院,图尔库大学);Miguel Hernández University of Elche(埃尔切米格尔·埃尔南德斯大学);Surrey Business School, University of Surrey(萨里商学院,萨里大学)
我们提出了一种新的框架,用于拟合添加剂分位数回归模型,它提供了良好的校准推断的条件分位数和快速自动估计的平滑参数,模型结构不同的分布GAM,同时保持相同的数值效率和稳定性。所提出的方法在统计上是严格的,在计算上是有效的,因为它们是基于Bissiri et al.(2016)的一般信念更新框架,以基于损失的推理,但通过调整Wood et al.(2016)的稳定拟合方法来计算。我们展示了弹球损失是如何统计次优相对于一个新的平滑概括,这也提供了快速估计方法。此外,我们提供了一种新的校准方法,有效地选择“学习率”平衡损失与平滑先验在推理过程中,从而获得可靠的分位数不确定性估计。我们的工作是出于概率电力负荷预测的应用程序,在这里使用,以证明所提出的方法。这里描述的方法由qgam R包实现,该包可在Comprehensive R Archive Network(CRAN)上获得。
The focus of modern biomedical studies has gradually shifted to explanation and estimation of joint effects of high dimensional predictors on disease risks. Quantifying uncertainty in these estimates may provide valuable insight into prevention strategies or treatment decisions for both patients and physicians. High dimensional inference, including confidence intervals and hypothesis testing, has sparked much interest. While much work has been done in the linear regression setting, there is lack of literature on inference for high dimensional generalized linear models. We propose a novel and c…
In this article, we propose a novel spatial global-local spike-and-slab selection prior for image-on-scalar regression. We consider a Bayesian hierarchical Gaussian process model for image smoothing, that uses a flexible Inverse-Wishart process prior to handle within-image dependency, and propose a general global-local spatial selection prior that extends a rich class of well-studied selection priors. Unlike existing constructions, we achieve simultaneous global (i.e, at covariate-level) and local (i.e., at pixel/voxel-level) selection by introducing `participation rate' parameters that measur…
This paper deals with a general class of transformation models that contains many important semiparametric regression models as special cases. It develops a self-induced smoothing for the maximum rank correlation estimator, resulting in simultaneous point and variance estimation. The self-induced smoothing does not require bandwidth selection, yet provides the right amount of smoothness so that the estimator is asymptotically normal with mean zero (unbiased) and variance-covariance matrix consistently estimated by the usual sandwich-type estimator. An iterative algorithm is given for the varia…
We address the problem of how to achieve optimal inference in distributed quantile regression without stringent scaling conditions. This is challenging due to the non-smooth nature of the quantile regression (QR) loss function, which invalidates the use of existing methodology. The difficulties are resolved through a double-smoothing approach that is applied to the local (at each data source) and global objective functions. Despite the reliance on a delicate combination of local and global smoothing parameters, the quantile regression model is fully parametric, thereby facilitating interpretat…
Estimating the spectral density function $f(w)$ for some $w\in [-π, π]$ has been traditionally performed by kernel smoothing the periodogram and related techniques. Kernel smoothing is tantamount to local averaging, i.e., approximating $f(w)$ by a constant over a window of small width. Although $f(w)$ is uniformly continuous and periodic with period $2π$, in this paper we recognize the fact that $w=0$ effectively acts as a boundary point in the underlying kernel smoothing problem, and the same is true for $w=\pm π$. It is well-known that local averaging may be suboptimal in kernel regression a…