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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.

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23466992 · Jun 202019922001200920172026
48 results for Mahalanobis acceptance region

New method calibrates reference distributions for bounded support.

problem Lack of principled method for bounded-support statistical reference distributions.
method Formulated maximum entropy on projective space of nonnegative measures.
result Prescribed acceptance region uniquely determines deformation parameter.

Proposes a method to estimate acceptance regions for many classes, including new ones.

problem Lack of methods to handle new classes in set-valued classification.
method Generalized Prediction Set (GPS) approach to estimate acceptance regions.
result Achieves a good balance between accuracy, efficiency, and anomaly detection.

Proposes a text perturbation method using a Mahalanobis metric to balance privacy and utility.

problem Low utility of text analysis when using spherical noise for privacy-preserving text embedding.
method Regularized Mahalanobis metric to add elliptical noise, accounting for embedding space density.
result Improves privacy statistics while maintaining utility, outperforming Laplace mechanism.

The paper develops a theory for speculative decoding acceptance criteria.

problem Speculative decoding's acceptance criteria and their rejection regions.
method Characterization of rejection regions as lower level sets of the target distribution, derivation of exact and margin-based certificates.
result Relaxed and tree-based acceptance criteria substantially enlarge the region of certified acceptance.

Develops a method for stress testing correlations of financial portfolios.

problem Stress testing correlations in financial asset portfolios.
method Parametric representation of correlations, Bayesian variable selection, joint distribution of stress scenarios.
result Inference of worst-case correlation scenarios using stress tests.

Flexible classifier using Mahalanobis distances for non-elliptical distributions.

problem Classifying non-elliptical and multimodal distributions.
method Semiparametric classifier based on Mahalanobis distances and generalized additive models.
result The proposed classifiers outperform traditional methods in high-dimensional, low-sample-size scenarios.

Extends Mahalanobis distance to Banach spaces for anomaly detection.

problem Anomaly detection in infinite-dimensional spaces.
method Generalizes Mahalanobis distance to Banach spaces via Cameron-Martin norm and variance norm.
result Kernelized nearest-neighbour Mahalanobis distance outperforms traditional methods for time series novelty detection.

Mahalanobis distance detects anomalies well, but not for classification.

problem Detecting anomalies in neural classifier outputs.
method Analyzes Mahalanobis distance-based anomaly detection method, revealing its reliance on information not useful for classification.
result Combining Mahalanobis and ODIN methods improves anomaly detection performance and robustness.

ECPv2 optimizes Lipschitz functions efficiently and scalably.

problem Global optimization of Lipschitz-continuous functions with unknown Lipschitz constants.
method Adapting the Every Call is Precious (ECP) framework, ECPv2 introduces adaptive lower bounds, Worst-m memory, and random projections to reduce computational cost and improve acceptance regions.
result ECPv2 retains ECP's no-regret guarantees with optimal finite-time bounds and expands the acceptance region with high probability.

Compressing data helps learn Mahalanobis metrics effectively.

problem Learning Mahalanobis metrics in high-dimensional spaces.
method Randomly compress data to train a full-rank metric in a reduced feature space.
result Theoretical guarantees on error for Mahalanobis metric learning, independent of ambient dimension.

Clustering and classification critically rely on distance metrics that provide meaningful comparisons between data points. We present mixed-integer optimization approaches to find optimal distance metrics that generalize the Mahalanobis metric extensively studied in the literature. Additionally, we generalize and impro…

2018-03-28abs ↗pdf ↗

We propose a low-rank approach to learning a Mahalanobis metric from data. Inspired by the recent geometric mean metric learning (GMML) algorithm, we propose a low-rank variant of the algorithm. This allows to jointly learn a low-dimensional subspace where the data reside and the Mahalanobis metric that appropriately f…

2018-06-14abs ↗pdf ↗

Previous work shows that adversarially robust generalization requires larger sample complexity, and the same dataset, e.g., CIFAR-10, which enables good standard accuracy may not suffice to train robust models. Since collecting new training data could be costly, we focus on better utilizing the given data by inducing t…

2019-05-25abs ↗pdf ↗

The study proposes a framework to accept OOD data based on competence scores.

problem Silent failures in Domain Generalization where models reject OOD data without proper justification.
method A learning to reject framework using proxy incompetence scores to predict trustworthiness.
result Increasing incompetence scores are predictive of reduced accuracy, but not always favorable for accuracy/rejection trade-off.

Timely detection of abrupt anomalies is crucial for real-time monitoring and security of modern systems producing high-dimensional data. With this goal, we propose effective and scalable algorithms. Proposed algorithms are nonparametric as both the nominal and anomalous multivariate data distributions are assumed unkno…

2018-09-14abs ↗pdf ↗

Bayesian nonparametric models improve OOD detection, especially with complex covariance structures.

problem Improving out-of-distribution detection methods, especially in complex scenarios.
method Proposes Bayesian nonparametric mixture models with hierarchical priors that generalize the Mahalanobis distance score.
result Bayesian nonparametric methods outperform existing OOD methods, especially in complex scenarios.

For many tasks and data types, there are natural transformations to which the data should be invariant or insensitive. For instance, in visual recognition, natural images should be insensitive to rotation and translation. This requirement and its implications have been important in many machine learning applications, a…

2015-02-04abs ↗pdf ↗

A visualization aids in comparing regression models by highlighting errors and correlations.

problem Comparing regression models is difficult due to varying hyper-parameters and metrics.
method Introduces a novel visualization approach using 2D residual space, Mahalanobis distance, and colormaps.
result Enhanced understanding of regression model performance differences and error distributions.

NUTS mixing time scales as d^(1/4) for Gaussian distributions.

problem Improving the efficiency of the No-U-Turn Sampler (NUTS) for Gaussian distributions.
method Coupling argument leveraging geometric structure of Gaussian concentration, uniformity analysis of NUTS transitions.
result The mixing time of NUTS scales as d^(1/4) for Gaussian distributions, up to logarithmic factors.

Proposes ridge regression on Riemannian manifolds for time-series prediction.

problem Time-series prediction on Riemannian manifolds.
method Combines Riemannian least-squares fitting via Bézier curves, empirical covariance on manifolds, and Mahalanobis distance regularization.
result Significant error reduction in synthetic spherical experiments and hurricane forecasting.

Study robustness of early-stopping GD for linear regression attacks.

problem Robustness of gradient-descent methods to adversarial attacks.
method Early-stopping strategies, gradient-descent, Mahalanobis attacks, feature-dependent learning rates, data transformations.
result Early-stopped GD is optimally robust to Euclidean-norm attacks but sub-optimal for Mahalanobis attacks.

This paper quantifies how hard it is to identify specific data points in machine learning models.

problem Quantifying the difficulty of identifying specific data points in machine learning models.
method Characterizing optimal attacks and privacy defences, deriving impacts of noise and misspecification, and proposing a new covariance attack.
result The Mahalanobis distance explains the hardness of fixed-target membership inference attacks.

New method combines neural networks with Monte Carlo for complex system reliability.

problem Estimating small failure probabilities in complex systems.
method Subset Simulation with Hamiltonian Neural Networks.
result High acceptance rates and computational efficiency in low-probability regions.

Develops a computationally tractable differentially private mean estimator called the balloon mean.

problem Robust mean estimation in the presence of outliers and heavy-tailed distributions.
method Iterative clipping procedure over Mahalanobis balls.
result Balloon mean is robust to outliers and outperforms existing estimators in contaminated settings.

2L-FUSE enhances feature sparsity through kernel learning.

problem Sparsity and feature selection in regression tasks.
method 2-Layered kernel machines for learning a shape matrix and feature direction identification.
result Minimal yet informative feature sets are identified without losing predictive performance.

We derive a new radial link for binary classification under shared elliptical distributions.

problem Binary classification under shared-generator elliptical class-conditional distributions.
method We derive the Bayes radial-link family from the within-class radius law and estimate it by a finite fractional-power stochastic-polynomial projection.
result The derived link is asymptotically Bayes-optimal and significantly better than QDA on various benchmarks.

A new algorithm estimates mean adaptively to covariance, faster and more flexible than existing methods.

problem Estimating mean of a distribution with unknown covariance efficiently and privately.
method Adaptive differentially private algorithm with optimal convergence rates and near-linear sample complexity.
result Achieves optimal rates of convergence with respect to the Mahalanobis norm Σ||\cdot||_Σ.

A new test validates ensemble models against the null hypothesis.

problem Validating ensemble models against the null hypothesis of a constant response.
method Randomized permutation test on SVEM model predictions.
result The test maintains Type I error rate even with more parameters than observations.

Simple conditions for comonotonic additive risk measures from acceptance sets.

problem Conditions for comonotonic additive risk measures from acceptance sets.
method Conditions on acceptance sets for induced comonotonic additive risk measures.
result Acceptance sets induce comonotonic additive risk measures if and only if the acceptance sets and their complements are stable under convex combinations of comonotonic random variables.

Single particle reconstruction (SPR) from cryo-electron microscopy (EM) is a technique in which the 3D structure of a molecule needs to be determined from its contrast transfer function (CTF) affected, noisy 2D projection images taken at unknown viewing directions. One of the main challenges in cryo-EM is the typically…

2016-11-10abs ↗pdf ↗

A new algorithm reduces online exp-concave optimization runtime.

problem Minimizing regret in online learning with exponentially concave losses.
method LightONS, a variant of Online Newton Step (ONS), reduces runtime to O(d2T+dωTlogT)O(d^2 T + d^ω\sqrt{T \log T}).
result Optimal regret with reduced runtime to O(d2T+dωTlogT)O(d^2 T + d^ω\sqrt{T \log T}).