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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.

168,695 papers · 148 categories

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48 results for sparse intervals

Novel confidence intervals improve convergence rates for sparse kernel-based models.

problem High computational cost in kernel-based learning models.
method Novel confidence intervals for Nyström method and sparse variational Gaussian process approximation.
result Improved performance bounds in regression and optimization problems.

Origin-destination (OD) matrices are often used in urban planning, where a city is partitioned into regions and an element (i, j) in an OD matrix records the cost (e.g., travel time, fuel consumption, or travel speed) from region i to region j. In this paper, we partition a day into multiple intervals, e.g., 96 15-min …

2018-11-13abs ↗pdf ↗

Conformal prediction improves prediction intervals for PCEs, especially in sparse cases.

problem Quantifying local model errors in PCEs for small datasets.
method Integration of conformal prediction methods (full and Jackknife+) into full and sparse PCEs.
result Better-calibrated prediction intervals for both full and sparse PCEs.

Post-processes deep networks with StoNet to quantify uncertainty.

problem Uncertainty quantification in predictions from large-scale deep neural networks.
method Feeds DNN output into StoNet, trains StoNet with sparse penalty, constructs prediction intervals.
result Proposed approach constructs honest confidence intervals with shorter lengths and better calibration.

In this article the package High-dimensional Metrics (\texttt{hdm}) is introduced. It is a collection of statistical methods for estimation and quantification of uncertainty in high-dimensional approximately sparse models. It focuses on providing confidence intervals and significance testing for (possibly many) low-dim…

2016-08-01abs ↗pdf ↗

The paper improves ranking by integrating covariates and sparse intrinsic scores.

problem Ranking items with incomplete preference scores explained by covariates.
method Extends BTL model with covariate information and sparse intrinsic scores, using penalized MLE.
result Developed debiased estimator for penalized MLE with distributional properties.

The package High-dimensional Metrics (\Rpackage{hdm}) is an evolving collection of statistical methods for estimation and quantification of uncertainty in high-dimensional approximately sparse models. It focuses on providing confidence intervals and significance testing for (possibly many) low-dimensional subcomponents…

2016-03-05abs ↗pdf ↗

Proposes a method for forecasting large-scale interval-valued time series.

problem Modeling and forecasting large-scale interval-valued time series.
method Feature extraction procedure involving auto-segmentation, clustering, and precision matrix estimation.
result The method enhances forecasting performance for large-scale interval-valued time series.

Random Forests provide interpretable prediction intervals with theoretical guarantees.

problem Lack of uncertainty estimates in machine learning point predictions.
method Out-of-Bag procedure for generating parametric and non-parametric prediction intervals.
result Proposed prediction intervals deliver correct coverage rates and narrow lengths.

Study improves confidence measures in medical imaging pipelines by addressing bias.

problem Bias in metric-based imaging pipelines compromises the efficiency of prediction intervals.
method Formalized symmetric and asymmetric CP formulations, analyzed bias effects, and validated empirically.
result Symmetric intervals are inflated by bias, while asymmetric intervals remain unaffected.

Conformal predictors, introduced by Vovk et al. (2005), serve to build prediction intervals by exploiting a notion of conformity of the new data point with previously observed data. In the present paper, we propose a novel method for constructing prediction intervals for the response variable in multivariate linear mod…

2009-02-11abs ↗pdf ↗

Most of the existing methods for sparse signal recovery assume a static system: the unknown signal is a finite-length vector for which a fixed set of linear measurements and a sparse representation basis are available and an L1-norm minimization program is solved for the reconstruction. However, the same representation…

2013-06-14abs ↗pdf ↗

The group of C1\mathcal C^1-diffeomorphisms of any sparse Cantor subset of a manifold is countable and discrete (possibly trivial). Thompson's groups come out of this construction when we consider central ternary Cantor subsets of an interval. Brin's higher dimensional generalizations nVnV of Thompson's group VV arise…

2014-11-18abs ↗pdf ↗

We develop a novel method for counterfactual analysis based on observational data using prediction intervals for units under different exposures. Unlike methods that target heterogeneous or conditional average treatment effects of an exposure, the proposed approach aims to take into account the irreducible dispersions …

2017-05-19abs ↗pdf ↗

Proposes two-stage robust and sparse distributed inference for large-scale data.

problem Statistical inference in large-scale, high-dimensional, and outlier-contaminated data.
method Two-stage approach: model selection with robust Lasso, fusion of local selections, and bootstrap methods for inference.
result Robust and computationally efficient inference procedures for variable selection, confidence intervals, and standard deviation approximations.

New estimators improve Rasch model item parameter estimation for sparse data.

problem Estimating item parameters in sparse Rasch model data.
method Random pairing maximum likelihood estimator (RP-MLE) and its bootstrapped variant (MRP-MLE).
result RP-MLE and MRP-MLE are minimax optimal and provide precise item parameter estimates.

Bayesian framework predicts aerodynamic uncertainty from sparse measurements.

problem Calibrating aerodynamic models with sparse and uncertain measurements.
method Bayesian latent Gaussian process for surrogate model calibration.
result Calibrated surrogate model accurately predicts aerodynamic uncertainty.

In this study, we analyzed the activity of monkey V1 neurons responding to grating stimuli of different orientations using inference methods for a time-dependent Ising model. The method provides optimal estimation of time-dependent neural interactions with credible intervals according to the sequential Bayes estimation…

2018-07-24abs ↗pdf ↗

Proposes an efficient method for sparse index tracking with 0\ell_0-norm constraints.

problem Constructing a sparse portfolio to track a financial index.
method Formulates a new problem using 0\ell_0-norm constraints, develops an efficient algorithm based on primal-dual splitting.
result Demonstrates effectiveness through experiments on S&P500 and Russell3000 datasets.

The paper proposes a method to infer Q-values online with Q-Learning.

problem High variance and instability in reinforcement learning algorithms.
method Adapting FCLT for a modified Q-learning approach and constructing confidence intervals.
result The proposed method provides more stable and reliable inference of Q-values.

Paper extends sparse alternatives to softmax for continuous domains, enabling efficient attention mechanisms.

problem Efficiently assigning zero probability to irrelevant categories in continuous domains.
method Extend alpha-entmax to continuous domains, introducing continuous-domain attention mechanisms.
result Continuous attention allows attending to time intervals and compact regions, improving text classification, machine translation, and visual question answering.

In modeling multivariate time series, it is important to allow time-varying smoothness in the mean and covariance process. In particular, there may be certain time intervals exhibiting rapid changes and others in which changes are slow. If such time-varying smoothness is not accounted for, one can obtain misleading inf…

2012-10-07abs ↗pdf ↗

Optimal multitask learning method for sparse heterogeneous datasets.

problem Efficiently learning from multiple related datasets with sparse task-specific differences.
method MOLAR estimator, combining weighted median and shrinkage.
result Improves estimation error dependence on data dimension compared to task-wise least squares.

New method predicts aphasia severity with narrower uncertainty intervals.

problem Predicting aphasia severity in stroke patients using neuroimages.
method Sparse heteroscedastic Bayesian high-dimensional regression with H-PROBE algorithm.
result H-PROBE provides narrower prediction intervals for aphasia severity.

Hypothesis testing in the linear regression model is a fundamental statistical problem. We consider linear regression in the high-dimensional regime where the number of parameters exceeds the number of samples (p>np> n). In order to make informative inference, we assume that the model is approximately sparse, that is th…

2017-04-26abs ↗pdf ↗

Develops a new method for uncertainty quantification in high-dimensional learning.

problem Challenges in uncertainty quantification in high-dimensional regression or learning problems.
method Data-driven approach for UQ that corrects bias terms from training data.
result Non-asymptotic confidence intervals that avoid overestimating uncertainty.

We address challenges in estimating parameters from adaptively collected data.

problem Estimating parameters from data collected adaptively leads to non-normal asymptotic distributions.
method We develop semi-parametric estimators that account for adaptivity in data collection.
result Our estimators are asymptotically normal under certain conditions.

We study parameter estimation and asymptotic inference for sparse nonlinear regression. More specifically, we assume the data are given by y=f(xβ)+εy = f( x^\top β^* ) + ε, where ff is nonlinear. To recover ββ^*, we propose an 1\ell_1-regularized least-squares estimator. Unlike classical linear regression, the correspondin…

2015-11-14abs ↗pdf ↗

Low-rank framework for task-specific LLM ranking from sparse comparisons.

problem Challenges in reliable task-specific ranking of LLMs under sparse, imbalanced comparisons.
method Low-rank modeling of task-by-model ability matrix, max-norm accurate estimator, task-wise top-K recovery guarantees, uncertainty quantification framework.
result Improves sample efficiency and produces tighter, better-calibrated ranking certificates.

This paper develops sparse alternatives to continuous distributions, including new types of Gaussians and attention mechanisms.

problem Creating flexible continuous distributions with varying support for machine learning applications.
method Defining ΩΩ-regularized prediction maps and Fenchel-Young losses for arbitrary domains, and deriving new types of Gaussians and attention mechanisms.
result Sparse alternatives to continuous distributions, including deformed exponential families and ββ-Gaussians, are introduced.

New bootstraps improve speed and accuracy for graph count functionals.

problem Efficiently counting subgraphs in large graphs.
method Developed two types of multiplier bootstraps: a fast, approximate linear one and a quadratic one for denser graphs.
result Both bootstraps provide valid inference and higher-order accuracy under different graph sparsity conditions.

EPICSCORE improves conformal scores by explicitly accounting for epistemic uncertainty.

problem Overconfident predictions in data-sparse regions due to lack of epistemic uncertainty.
method Model-agnostic approach using Bayesian techniques like Gaussian Processes, Dropout, and Regression Trees.
result Enhanced predictive intervals that adaptively expand in sparse data regions and maintain compact intervals in abundant data.

Having a regression model, we are interested in finding two-sided intervals that are guaranteed to contain at least a desired proportion of the conditional distribution of the response variable given a specific combination of predictors. We name such intervals predictive intervals. This work presents a new method to fi…

2014-02-24abs ↗pdf ↗