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arXiv research

A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,878 papers · 148 categories

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48 results for covariance boosting

GBMixed boosts mixed models for clustered data, estimating mean and variance flexibly.

problem Flexible estimation of mean and variance components in clustered data.
method Gradient Boosting framework for linear mixed models with likelihood-based gradients.
result GBMixed accurately recovers complex nonlinear fixed effects and covariances.

CBGP boosts GP covariance to model spatiotemporal irregularities.

problem Overfitting and overconfident uncertainty in nonstationary GP models.
method Boosting covariance priors, partially-whitened observations, gradient descent-like procedure.
result Accurate and reliable SBAS ionospheric corrections in challenging space weather.

Improved portfolio optimization method yields better risk-adjusted returns.

problem Optimizing global minimum variance portfolios with reduced risk.
method k-fold boosted kk-BAHC covariance cleaning procedure for correlation matrices.
result Our method outperforms other filtering methods in Sharpe ratios, despite higher turnover.

BoXHED boosts hazard estimation for dynamic health risk scores.

problem Analyzing time-varying health vitals for disease onset prediction.
method Gradient boosting for nonparametric hazard function estimation with time-dependent covariates.
result Novel interaction effects among risk factors identified in cardiovascular disease onset data.

Gradient Boosted Mixed Models estimate mean and variance components for clustered data.

problem Limited flexibility in linear mixed models for complex settings.
method Gradient Boosting extended to mixed models with likelihood-based gradients and flexible base learners.
result Accurate recovery of variance components and improved predictive accuracy.

Machine learning boosts RCT efficiency by controlling type I error and improving statistical power.

problem Improving statistical efficiency in RCTs with complex covariate adjustments.
method Machine learning-assisted adjustment under Rosenbaum's framework for exact tests.
result The proposed method robustly controls type I error and significantly boosts statistical efficiency.

Develop gradient boosting for estimating covariate-dependent GP distributions in insurance.

problem Estimating covariate-dependent Generalized Pareto distributions in insurance.
method Developing a statistical learning theory for gradient boosting.
result Deriving non-asymptotic error bounds for the boosting estimator.

Enhances GBDT robustness with one-hot encoding and regularization.

problem Low robustness of GBDT models against covariate perturbation.
method One-hot encoding to linear framework, risk decomposition, L1L_1 or L2L_2 regularization.
result Regularization enhances GBDT robustness.

Stagewise boosting improves gradient boosting for distributional regression.

problem Vanishing gradient in gradient boosting for distributional regression leads to suboptimal models.
method Proposes a stagewise boosting-type algorithm for distributional regression, combining stagewise regression ideas with gradient boosting and incorporating a novel regularization method, correlation filtering.
result The proposed algorithm provides better results, especially for complex distributions, by reducing the risk of being trapped in a local optimum.

Given functional data from a survival process with time-dependent covariates, we derive a smooth convex representation for its nonparametric log-likelihood functional and obtain its functional gradient. From this, we devise a generic gradient boosting procedure for estimating the hazard function nonparametrically. An i…

2017-01-27abs ↗pdf ↗

The paper analyzes boosting and minimum-1\ell_1-norm classifiers in high dimensions.

problem Understanding the generalization error and optimal Bayes error in boosting.
method High-dimensional asymptotic theory, Gaussian comparison techniques, uniform deviation argument.
result Precise characterizations of boosting test error and optimal Bayes error.

Unified probabilistic gradient boosting for entire conditional distribution modeling.

problem Creating accurate probabilistic forecasts from regression tasks.
method Unified probabilistic gradient boosting framework using XGBoost and LightGBM, modeling conditional moments or CDF via Normalizing Flows.
result Achieves state-of-the-art forecast accuracy.

We propose a black-box variational inference method to approximate intractable distributions with an increasingly rich approximating class. Our method, termed variational boosting, iteratively refines an existing variational approximation by solving a sequence of optimization problems, allowing the practitioner to trad…

2016-11-20abs ↗pdf ↗

sgboost reduces variable selection bias in boosting with balanced group selection.

problem Reduces variable selection bias in boosting algorithms.
method Simulation-based approach to balance selection frequencies of base-learners.
result Demonstrates efficacy through simulations and flexible group variable selection.

Boosting ridge regression for high-dimensional data classification reduces computational cost and improves learning time.

problem High computational demand of inverting regularised covariance matrix in ridge regression for high-dimensional problems.
method Train an ensemble of ridge regressors in randomly projected subspaces, then combine them using adaptive boosting.
result Effective in terms of learning time and improved predictive performance in some cases.

NeurT-FDR controls FDR by incorporating auxiliary covariates in deep learning.

problem Controlling FDR in complex large-scale problems with indirect relations among covariates.
method NeurT-FDR uses a deep Black-Box framework that parametrizes test-level covariates as a neural network and adjusts auxiliary covariates through a regression framework.
result NeurT-FDR makes substantially more discoveries in real datasets compared to competitive baselines.

BayesBoost combines boosting and Bayesian methods for linear mixed models, improving uncertainty estimation and variable selection.

problem Lack of straightforward uncertainty estimation for parameters in high-dimensional linear mixed models.
method BayesBoost: Combines boosting and Bayesian inference for linear mixed models.
result Improves uncertainty estimation and variable selection in linear mixed models.

Proposes a new Q-learning method for survival outcomes in clinical trials.

problem Incomplete follow-up data and nonlinear covariate effects in clinical trials.
method Combines Buckley-James boosting with flexible base learners for estimating optimal treatment regimes.
result Improves treatment decision accuracy and stability in longitudinal clinical trials.

Parallel gradient boosting speeds up multi-output regression.

problem Efficiently predicting entire conditional distributions.
method Modification of gradient boosting to use a common descent direction.
result Significantly faster and comparable performance to state-of-the-art boosting libraries.

Spectral deconfounding improves machine learning models by reducing hidden confounding effects.

problem Machine learning models can be misled by hidden confounders, leading to unreliable predictions.
method Develops a nonlinear spectral deconfounding framework for gradient boosting that modifies boosting dynamics to slow down in confounding-aligned directions.
result Spectrally deconfounded boosting improves estimation of the target function under hidden confounding and is more scalable.

NeurT-FDR controls FDR by incorporating feature hierarchy.

problem Controlling FDR in complex, large-scale hypothesis testing problems.
method NeurT-FDR uses a neural network to parametrize test-level covariates and a regression framework to adjust feature hierarchy.
result NeurT-FDR makes substantially more discoveries than competitive baselines.

Machine learning improves sub-seasonal climate forecasting, especially gradient boosting and deep learning.

problem Predicting climate variables like temperature and precipitation in 2-week to 2-month time scales.
method Carefully constructed feature representations and ML approaches including gradient boosting and deep learning.
result ML methods can outperform climatological baselines and improve prediction accuracy.

Variational inference (VI) provides fast approximations of a Bayesian posterior in part because it formulates posterior approximation as an optimization problem: to find the closest distribution to the exact posterior over some family of distributions. For practical reasons, the family of distributions in VI is usually…

2016-11-17abs ↗pdf ↗

A new method boosts survival analysis by stratifying patients and removing noise covariates.

problem Weak detection of treatment differences in randomized clinical trials due to patient heterogeneity.
method 5-Step Stratified Testing and Amalgamation Routine (5-STAR) using elastic net Cox regression and conditional inference trees.
result The 5-STAR routine significantly improves power in detecting treatment effects compared to traditional methods.

Boosted Control Functions improve prediction under distributional shifts.

problem Prediction under distributional shifts in the presence of hidden confounding.
method Boosted Control Function (BCF) and ControlTwicing algorithm.
result BCF allows for distribution generalization and invariance under nonlinear, non-identifiable structural functions.

Technology and collaboration enable dramatic increases in the size of psychological and psychiatric data collections, but finding structure in these large data sets with many collected variables is challenging. Decision tree ensembles like random forests (Strobl, Malley, and Tutz, 2009) are a useful tool for finding st…

2015-11-06abs ↗pdf ↗

The paper forecasts joint electricity demand across 14 British regions using additive models.

problem Forecasting regional electricity demand with cross-regional dependencies.
method Modified Cholesky parametrisation for multivariate Gaussian model, gradient boosting for model selection.
result The proposed model outperforms non-Gaussian copula-based models in forecasting.

Paper compares feature selection methods using GCM and LOCO, showing GCM methods generally outperform LOCO.

problem Feature selection and importance estimation in model-agnostic settings.
method Comparison of feature selection methods related to GCM and LOCO under three model settings.
result GCM-related methods generally outperform LOCO under suitable regularity conditions, as shown by theoretical and empirical results.

Proposes a two-stage method for estimating heterogeneous treatment effects using gradient boosting trees.

problem Estimating heterogeneous treatment effects in randomized clinical trials with high-dimensional predictive markers.
method Two-stage statistical learning procedure using gradient boosting trees (XGBoost) to estimate main effects and HTE.
result Improves efficiency in estimating heterogeneous treatment effects through nonparametric function estimation.

Integrates ML with operations knowledge to improve distributional forecasts in healthcare.

problem Challenges of ML in operational settings, especially lack of distributional information and integration of operations literature.
method Introduces Boosted Generalized Normal Distribution (bbGND) using gradient boosting with tree learners.
result Improves wait and service time forecasting by 6% and 9% compared to ML benchmarks.

A new model integrates claim history and covariates for non-life insurance reserving.

problem Lack of information in traditional reserving models for non-life insurance claims.
method Hierarchical reserving model integrating claim history and covariates.
result Flexibility and robustness of the hierarchical reserving model demonstrated.