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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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48 results for leverage scores

The statistical leverage scores of a complex matrix ACn×dA\in\mathbb{C}^{n\times d} record the degree of alignment between col(A)(A) and the coordinate axes in Cn\mathbb{C}^n. These score are used in random sampling algorithms for solving certain numerical linear algebra problems. In this paper we present a max-plus algebr…

2016-09-29abs ↗pdf ↗

We explain theoretically a curious empirical phenomenon: "Approximating a matrix by deterministically selecting a subset of its columns with the corresponding largest leverage scores results in a good low-rank matrix surrogate". To obtain provable guarantees, previous work requires randomized sampling of the columns wi…

2014-04-06abs ↗pdf ↗

Generalizes leverage score sampling for neural networks, accelerating kernel methods and deep learning.

problem Accelerating kernel methods and deep learning training.
method Generalizes leverage score sampling to neural networks and proves equivalence to neural tangent kernel ridge regression.
result Equivalence between regularized neural network and neural tangent kernel ridge regression under leverage score sampling initialization.

Leverage score sampling provides an appealing way to perform approximate computations for large matrices. Indeed, it allows to derive faithful approximations with a complexity adapted to the problem at hand. Yet, performing leverage scores sampling is a challenge in its own right requiring further approximations. In th…

2018-10-31abs ↗pdf ↗

Efficiently approximates statistical leverage scores for faster KRR.

problem Accurately estimating statistical leverage scores for fast KRR.
method Analytic formula for statistical leverage scores, leveraging kernel spectral density.
result Linear time approximation with theoretical guarantees, significantly faster than existing methods.

Binary testing for softmax models requires many samples, similar to leverage score models.

problem Binary hypothesis testing for softmax models and leverage score models.
method Analyzing sample complexity and drawing analogies between models.
result Sample complexity is asymptotically \(O(ε^{-2})\), where \(ε\) is the distance between model parameters.

Active learning aims to obtain a classifier of high accuracy by using fewer label requests in comparison to passive learning by selecting effective queries. Many active learning methods have been developed in the past two decades, which sample queries based on informativeness or representativeness of unlabeled data poi…

2015-07-15abs ↗pdf ↗

In many real-world machine learning applications, unlabeled data are abundant whereas class labels are expensive and scarce. An active learner aims to obtain a model of high accuracy with as few labeled instances as possible by effectively selecting useful examples for labeling. We propose a new selection criterion tha…

2018-12-06abs ↗pdf ↗

SALSA efficiently approximates leverage scores for big data, improving ARMA model fitting.

problem Efficiently approximating leverage scores for large matrices.
method Sequential approximate leverage-score algorithm (SALSA) using randomized numerical linear algebra.
result SALSA approximates leverage scores within (1+O(ε))(1 + O({\varepsilon})) with high probability.

We consider the problem of exact recovery of any m×nm\times n matrix of rank ϱ\varrho from a small number of observed entries via the standard nuclear norm minimization framework. Such low-rank matrices have degrees of freedom (m+n)ϱϱ2(m+n)\varrho - \varrho^2. We show that any arbitrary low-rank matrices can be recovered exa…

2015-03-22abs ↗pdf ↗

This paper improves matrix completion by leveraging element importance and non-uniform sampling.

problem The challenge of completing low-rank matrices from noisy, subsampled measurements.
method Employing leverage scores to characterize element importance and devising a biased sampling procedure.
result Theoretical and empirical evidence shows that a smaller number of entries (about O(nrlog2(n))O(nr\log^2(n))) can recover a low-rank matrix with noise.

BSAC improves credit scoring models by leveraging autoencoders and addressing imbalanced datasets.

problem Imbalanced and heterogeneous credit scoring datasets.
method Bagging Supervised Autoencoder Classifier (BSAC) that uses autoencoders and undersampling.
result BSAC improves classification of loan applicants, demonstrating robustness and effectiveness.

New algorithm samples matrix rows proportional to their ℓ_p norm in a turnstile data stream.

problem Sampling rows of a dynamic matrix efficiently in a turnstile data stream.
method Develops a novel algorithm for sampling rows proportional to their ℓ_p norm in a turnstile data stream, returning sampled row indexes and approximated sampling probabilities.
result Achieves (1+ε)(1+\varepsilon) approximation for logistic regression in a turnstile data stream with polynomial sketch size.

For any matrix A in R^(m x n) of rank ρ, we present a probability distribution over the entries of A (the element-wise leverage scores of equation (2)) that reveals the most influential entries in the matrix. From a theoretical perspective, we prove that sampling at most s = O ((m + n) ρ^2 ln (m + n)) entries of the ma…

2013-10-14abs ↗pdf ↗

ScoreMatchingRiesz improves debiased machine learning and policy effects estimation.

problem Improving debiased machine learning and policy effects estimation.
method Score matching and Riesz representer estimation.
result Estimates policy path for continuous treatments, improving interpretability.

Given a matrix ARn×d\mathbf{A}\in\mathbb{R}^{n\times d} and a vector bRdb \in\mathbb{R}^{d}, we show how to compute an εε-approximate solution to the regression problem minxRd12Axb22 \min_{x\in\mathbb{R}^{d}}\frac{1}{2} \|\mathbf{A} x - b\|_{2}^{2} in time O~((n+dκsum)slogε1) \tilde{O} ((n+\sqrt{d\cdotκ_{\text{sum}}})\cdot s\cdot\logε^{-1}) where …

2017-11-22abs ↗pdf ↗

Neural score matching improves high-dimensional causal inference by using neural networks for balancing scores.

problem Impracticality of traditional matching methods in high-dimensional datasets due to the curse of dimensionality.
method Develops neural networks to create non-trivial, multivariate balancing scores for high-dimensional causal inference.
result Neural score matching outperforms other methods in treatment effect estimation and reducing imbalance on high-dimensional datasets.

Although deep learning has been applied to successfully address many data mining problems, relatively limited work has been done on deep learning for anomaly detection. Existing deep anomaly detection methods, which focus on learning new feature representations to enable downstream anomaly detection methods, perform in…

2019-11-19abs ↗pdf ↗

Study improves denoising score matching under relaxed manifold assumptions.

problem Improving denoising score matching under relaxed manifold assumptions.
method Model density with nonparametric Gaussian mixtures, relax manifold assumption, derive non-asymptotic bounds.
result Non-asymptotic bounds on approximation and generalization errors, rates of convergence determined by intrinsic dimension.

Proposes SD-KDE for density estimation using debiased kernel density with score-based adjustments.

problem Density estimation with bias in kernel density estimation.
method Adjusts data points by taking a step along the estimated score function, then applies standard KDE with modified bandwidth.
result Significantly reduces mean integrated squared error compared to standard Silverman KDE, especially with noisy score function estimates.

Knowledge graph based simple question answering (KBSQA) is a major area of research within question answering. Although only dealing with simple questions, i.e., questions that can be answered through a single knowledge base (KB) fact, this task is neither simple nor close to being solved. Targeting on the two main ste…

2019-04-04abs ↗pdf ↗

Paper proposes a method to reduce hallucinations in diffusion models using Laplacian score sharpening.

problem Hallucinations in diffusion models create incoherent or unrealistic samples.
method Post-hoc adjustment to the score function during inference using Laplacian approximation.
result Significantly reduces the rate of hallucinated samples across various data types.

Semi-Implicit Variational Inference (SIVI) is improved with SIVI-SM using score matching.

problem Intractable densities in variational distributions hinder SIVI training.
method SIVI-SM uses score matching to handle intractable densities in a minimax formulation.
result SIVI-SM outperforms ELBO-based SIVI methods in Bayesian inference tasks.

We study the problem of interpreting trained classification models in the setting of linguistic data sets. Leveraging a parse tree, we propose to assign least-squares based importance scores to each word of an instance by exploiting syntactic constituency structure. We establish an axiomatic characterization of these i…

2019-02-11abs ↗pdf ↗

Paper proposes a new method for estimating treatment effects using interpretable deep learning models.

problem Estimating treatment effects from observational data with interpretability.
method Proposes a novel objective function using energy distance balancing score and neural additive models for improved interpretability.
result Demonstrates superior performance over state-of-the-art methods in semi-synthetic experiments.

Paper tackles transparency and auditability of machine learning in credit scoring.

problem Missed potential in using modern machine learning for credit scoring due to lack of transparency.
method Develops a framework for making black box machine learning models transparent, auditable, and explainable.
result Comparable interpretability can be achieved with machine learning while maintaining predictive power.

We give the first algorithm for kernel Nyström approximation that runs in *linear time in the number of training points* and is provably accurate for all kernel matrices, without dependence on regularity or incoherence conditions. The algorithm projects the kernel onto a set of ss landmark points sampled by their *rid…

2016-05-24abs ↗pdf ↗

This paper enhances uplift modeling for multi-treatment marketing campaigns.

problem Optimizing marketing strategies by selecting individuals likely to respond to different treatments.
method Leveraging score ranking and calibration techniques.
result Improves overall performance of marketing campaigns.

New method assesses individual training points' privacy risk without retraining.

problem Privacy vulnerability of individual training points in membership inference attacks.
method Derives a closed-form decomposition of individual black-box MIA vulnerability, extending to deep networks.
result Proposes a surrogate score operating on last-layer representations that requires only a single trained model.