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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.

168,657 papers · 148 categories

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83166249332 · Jun 202019922001200920172026
48 results for quadratic losses

Paper develops methods for non-quadratic loss low-rank matrix recovery.

problem Recovery of low-rank matrices with non-quadratic losses.
method Projected gradient method with a regularity projection oracle.
result Projected gradient method converges globally and linearly.

Extends quadratic loss for SVM and deep learning to improve pattern correlation.

problem Improving generalization in supervised binary classification and regression tasks.
method Extends quadratic loss, restarts from problem (8) in [3], proposes new algorithms, uses multiple kernel learning.
result Comparable results with standard losses and parameterized quadratic loss.

Optimal algorithm for LQR control with improved regret bound.

problem Nonstochastic control with quadratic losses (LQR control).
method Online algorithm with optimal dynamic regret of ildeO(extmax{n1/3TV(M1:n)2/3,1}) ilde{O}( ext{max}\{n^{1/3} \mathcal{TV}(M_{1:n})^{2/3}, 1\}).
result Improves the best known rate of ildeO(n(TV(M1:n)+1)) ilde{O}(\sqrt{n (\mathcal{TV}(M_{1:n})+1)} ) for general convex losses.

This paper aims at refined error analysis for binary classification using support vector machine (SVM) with Gaussian kernel and convex loss. Our first result shows that for some loss functions such as the truncated quadratic loss and quadratic loss, SVM with Gaussian kernel can reach the almost optimal learning rate, p…

2017-02-28abs ↗pdf ↗

For semi-supervised techniques to be applied safely in practice we at least want methods to outperform their supervised counterparts. We study this question for classification using the well-known quadratic surrogate loss function. Using a projection of the supervised estimate onto a set of constraints imposed by the u…

2016-02-25abs ↗pdf ↗

Bayesian neural networks are shown to be minimax and admissible under certain conditions.

problem Optimality of Bayesian neural networks in deep learning models.
method Analysis of decision rules induced by BNNs in the normal location model under quadratic loss.
result A hyperprior on the effective output variance yields a minimax and admissible decision rule.

Q-SHAP efficiently calculates feature contributions in boosting trees.

problem Global evaluation of feature contributions in tree models.
method Q-SHAP, an efficient algorithm that reduces Shapley values calculation to polynomial time.
result Q-SHAP improves computational efficiency and enhances accuracy of feature-specific R2R^2 estimates.

Study on neural networks with quadratic activation functions, focusing on optimization and generalization.

problem Understanding the dynamics and generalization of neural networks with quadratic activation in the over-parametrized regime.
method Teacher-student scenario, empirical loss landscape analysis, gradient descent dynamics, numerical experiments.
result Conditions for the neural network to recover the teacher and achieve small generalization error.

One-pass SGD dynamics in overparameterized quadratic networks show slow escape from poor solutions.

problem Slow escape from poor generalization solutions in overparameterized neural networks.
method Analysis of one-pass SGD dynamics using ordinary differential equations for overlap matrices.
result Overparameterization only modestly accelerates escape from poor solutions.

Despite their practical success, a theoretical understanding of the loss landscape of neural networks has proven challenging due to the high-dimensional, non-convex, and highly nonlinear structure of such models. In this paper, we characterize the training landscape of the mean squared error loss for neural networks wi…

2019-12-31abs ↗pdf ↗

A new method automatically and dynamically sets learning rates in deep learning.

problem Determining the appropriate learning rate in deep learning tasks is challenging and often subjective.
method Local Quadratic Approximation (LQA) to automatically and dynamically set learning rates.
result The proposed method leads to nearly optimal learning rates in a computationally efficient way.

New analysis improves SGD for robust and quantile regression with sub-quadratic convergence.

problem Improving SGD for robust and quantile regression with sub-quadratic convergence.
method Piecewise Lyapunov function for first-order differentiable functions.
result First geometrical convergence result for sub-quadratic SGD.

New findings show GD converges to a linear interpolator even with quadratic loss function under certain conditions.

problem Understanding convergence of Gradient Descent with quadratic loss functions.
method Parameterized linear regression with quadratic loss function, empirical and theoretical analysis.
result Gradient Descent converges to a linear interpolator even with quadratic loss function under the Edge of Stability regime.

Sharp asymptotics reveal how network width controls learnability in quadratic neural networks.

problem Understanding learnability in overparameterized quadratic neural networks.
method Mapping ERM to convex matrix sensing with nuclear norm penalization.
result Characterization of global minima and precise generalization thresholds.

RFRBoost uses random features to boost deep residual neural networks, improving performance and computational efficiency.

problem Improving performance of deep residual neural networks (RFNNs) while preserving convex optimization benefits.
method Random Feature Representation Boosting (RFRBoost) using boosting theory and random features at each layer.
result RFRBoost significantly outperforms RFNNs and end-to-end trained MLP ResNets in small- to medium-scale tabular datasets.

We study the problem of controlling linear time-invariant systems with known noisy dynamics and adversarially chosen quadratic losses. We present the first efficient online learning algorithms in this setting that guarantee O(T)O(\sqrt{T}) regret under mild assumptions, where TT is the time horizon. Our algorithms rely …

2018-06-19abs ↗pdf ↗

Ensemble techniques are powerful approaches that combine several weak learners to build a stronger one. As a meta-learning framework, ensemble techniques can easily be applied to many machine learning methods. Inspired by ensemble techniques, in this paper we propose an ensemble loss functions applied to a simple regre…

2018-10-25abs ↗pdf ↗

The paper debiases mini-batch approximations in deep learning for more accurate optimization and uncertainty quantification.

problem Bias in mini-batch approximations distorts the shape of quadratic approximations used in deep learning.
method Developed and evaluated debiasing strategies for mini-batch approximations.
result Debiasing strategies improve the accuracy of second-order optimization and uncertainty quantification in deep learning.

We propose in this paper a differentiable learning loss between time series, building upon the celebrated dynamic time warping (DTW) discrepancy. Unlike the Euclidean distance, DTW can compare time series of variable size and is robust to shifts or dilatations across the time dimension. To compute DTW, one typically so…

2017-03-05abs ↗pdf ↗

Full-batch GD outperforms one-pass SGD in learning a single-index model with quadratic activation.

problem Learning a single-index model with quadratic activation using gradient descent.
method Full-batch gradient descent compared to one-pass stochastic gradient descent (SGD) on a correlation loss.
result Full-batch GD requires only ndn \simeq d samples for strong recovery, while one-pass SGD requires ndlogdn \gtrsim d\log d samples.

The paper develops methods for time-varying constrained online convex optimization.

problem Time-varying loss and constraint functions in online convex optimization.
method Model-based augmented Lagrangian methods (MALM) for time-varying and delayed feedback.
result Sublinear regret and constraint violation for both time-varying and delayed feedback scenarios.

Traditional dictionary learning methods are based on quadratic convex loss function and thus are sensitive to outliers. In this paper, we propose a generic framework for robust dictionary learning based on concave losses. We provide results on composition of concave functions, notably regarding super-gradient computati…

2017-11-02abs ↗pdf ↗

A new method improves adversarial robustness and interpretability with reduced training time.

problem Adversarial attacks on deep neural networks.
method A novel regularizer incorporating first and second order information via a quadratic approximation to the adversarial loss.
result Single iteration of the proposed regularizer achieves stronger robustness than prior methods.

Closed-form polynomial approximations replace MLPs in transformers, enabling new interpretability methods.

problem Replacing MLPs with polynomial approximations for transformer models.
method Theoretical derivation of closed-form least-squares approximations of MLPs and GLUs using polynomial functions.
result Polynomial approximations explain over 95% of MLP and GLU outputs' variance, enabling interpretability.

New bounds show linear predictors rarely overfit with certain optimization methods.

problem Bounding test error for linear predictors with stochastic optimization methods.
method Coupling argument for fixed point methods like stochastic and batch mirror descent.
result Locally-adapted rates that depend on predictor properties, not global problem structure.

The paper sets lower bounds for adversarial robustness in multiclass classification.

problem Adversarial robustness in multiclass classification with arbitrary loss functions.
method Dual and barycentric reformulations for robust risk minimization.
result Sharp lower bounds for adversarial risks are computed efficiently.

Method identifies shifts leading to large model performance differences.

problem Detecting shifts in distribution that affect model performance.
method Parametric changes in causal mechanisms define robustness sets; worst-case optimization problem approximated as non-convex quadratic.
result Second-order approximation of worst-case loss for small shifts, leading to efficient algorithms.

The least absolute shrinkage and selection operator (lasso) and ridge regression produce usually different estimates although input, loss function and parameterization of the penalty are identical. In this paper we look for ridge and lasso models with identical solution set. It turns out, that the lasso model with shri…

2014-01-10abs ↗pdf ↗

Bayes-optimal learning of a neural network with quadratic activations is achieved with GAMP-RIE.

problem Learning a neural network with quadratic activations from quadratic samples.
method Combining approximate message passing with rotationally invariant matrix denoising.
result Derives a closed-form expression for Bayes-optimal test error.

Self-test loss functions improve data-driven modeling of weak-form operators and gradient flows.

problem Challenges in selecting test functions for data-driven modeling involving weak-form operators and gradient flows.
method Introducing self-test loss functions that depend on unknown parameters and are quadratic.
result Self-test loss functions conserve energy for gradient flows and coincide with log-likelihood ratios for stochastic differential equations.

Study non-asymptotic bounds for robust estimators under misspecified models.

problem Evaluate performance of robust estimators under adversarial conditions.
method Propose a general approach to adversarial risk analysis, including investigations on generalization and approximation errors.
result Establish non-asymptotic upper bounds for adversarial excess risk under Lipschitz loss functions.

Fast classification for sparse models, even with correlated features.

problem Sparse classification with many correlated features.
method Linear and quadratic surrogate cuts, priority queue, and analytical solution for exponential loss.
result 2 to 5 times faster than previous approaches, interpretable models with comparable accuracy.