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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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85169254338 · Jun 202019922001200920172026
48 results for stochastic corruption

We extend the model of stochastic bandits with adversarial corruption (Lykouriset al., 2018) to the stochastic linear optimization problem (Dani et al., 2008). Our algorithm is agnostic to the amount of corruption chosen by the adaptive adversary. The regret of the algorithm only increases linearly in the amount of cor…

2019-09-04abs ↗pdf ↗

Improved SGD for robust linear and ReLU regression with adversarial corruptions.

problem Robust regression with adversarial corruptions in streaming data.
method Stochastic gradient descent (SGD-exp) with exponentially decaying step size.
result Nearly linear convergence to true parameter with up to 50% Massart corruption rate.

We study the stochastic multi-armed bandits problem in the presence of adversarial corruption. We present a new algorithm for this problem whose regret is nearly optimal, substantially improving upon previous work. Our algorithm is agnostic to the level of adversarial contamination and can tolerate a significant amount…

2019-02-22abs ↗pdf ↗

We introduce a new model of stochastic bandits with adversarial corruptions which aims to capture settings where most of the input follows a stochastic pattern but some fraction of it can be adversarially changed to trick the algorithm, e.g., click fraud, fake reviews and email spam. The goal of this model is to encour…

2018-03-25abs ↗pdf ↗

New method generates clean data from corrupted observations.

problem Generating clean data from corrupted observations.
method Iterative update of a transport map using black-box corruption channel access.
result Converges to a self-consistent transport map that effectively inverts the corruption channel.

New algorithm detects communities even with corrupted data, reaching Kesten-Stigum threshold.

problem Robust community detection in stochastic block model with node corruptions.
method Polynomial-time algorithm using Grothendieck norm of principal submatrices.
result First algorithm to achieve weak recovery at Kesten-Stigum threshold with node corruptions.

Improved regret bounds for Tsallis-INF in adversarial bandits and corruptions.

problem Adversarial bandits and corruptions in multiarmed bandit problems.
method Improved regret bounds for Tsallis-INF algorithm.
result Achieves $\mathcal{O}\left(\left(\sum_{i eq i^*} \frac{1}{Δ_i} ight)\log_+\left(\frac{(K-1)T}{\left(\sum_{i eq i^*} \frac{1}{Δ_i} ight)^2} ight)+\sqrt{C\left(\sum_{i eq i^*}\frac{1}{Δ_i} ight)\log_+\left(\frac{(K-1)T}{C\sum_{i eq i^*}\frac{1}{Δ_i}} ight)} ight)$ regret bound.

We study a variant of the stochastic multi-armed bandit (MAB) problem in which the rewards are corrupted. In this framework, motivated by privacy preservation in online recommender systems, the goal is to maximize the sum of the (unobserved) rewards, based on the observation of transformation of these rewards through a…

2017-08-16abs ↗pdf ↗

Algorithm maximizes total reward in multi-agent bandits with adversarial corruptions.

problem Maximizing total reward in multi-agent bandits with adversarial corruptions.
method Proposes a cooperative learning algorithm robust to adversarial corruptions.
result Demonstrates an additive O((L/Lmin)C)O((L / L_{\min}) C) regret term for an adversary with unknown corruption budget.

Lattice investment projects support process model with corruption is formulated and analyzed. The model is based on the Ising lattice model of ferromagnetic but takes deal with the social phenomenon. Set of corruption agents is considered. It is supposed that agents are placed in sites of the lattice. Agents take decis…

2019-01-25abs ↗pdf ↗

Unified framework for corruption-robust linear bandits with optimal gap-dependent misspecification bounds.

problem Effective learning in linear bandits with corrupted rewards across different corruption models.
method Unified framework for analyzing strong and weak corruption, connection to gap-dependent misspecification, and specialized algorithm.
result Optimal bounds for gap-dependent misspecification in linear bandits.

CRIMED optimizes regret in bandits with unbounded stochastic corruption.

problem Minimizing regret in bandits with arbitrary unbounded corruptions.
method Introduces CRIMED, an asymptotically-optimal algorithm for Gaussian distributions with known variance.
result Achieves exact lower bound on regret for Gaussian distributions with high corruption probability.

Efficient algorithm detects communities in noisy graphs with robustness.

problem Community detection in stochastic block models with adversarial corruptions.
method Efficient algorithm using semidefinite programming for robust clustering.
result Achieves error O(ε)+eC2(1±o(1))O(ε) + e^{-\frac{C}{2} (1 \pm o(1))} for εε-fraction of corruptions.

Improved linear regression with privacy and robustness guarantees.

problem Private and robust linear regression with adversarial corruption.
method Differentially private stochastic gradient descent with full-batch gradient descent and adaptive clipping.
result Near optimal sample complexity for both private and robust linear regression.

RILA learns HQMMs robustly against adversarial corruption.

problem Robustness of HQMM learning algorithms under adversarial perturbations.
method Adversarially Corrupted HQMM (AC-HQMM) and Robust Iterative Learning Algorithm (RILA).
result RILA outperforms existing algorithms in convergence stability, corruption resilience, and physical validity.

The paper shows optimal robustness against adversarial corruption in sequential decision-making problems.

problem Optimal robustness to adversarial corruption in online decision-making problems.
method Investigates prediction with expert advice and multi-armed bandit problems, focusing on algorithms with decreasing learning rates and second-order regret bounds.
result Optimal robustness can be expressed by a square-root dependency on the amount of corruption, achieving O(logNΔ+ClogNΔ)O(\frac{\log N}{\Delta} + \sqrt{\frac{C \log N}{\Delta}})-regret.

Develops a strategy to minimize loss in both stochastic and adversarial environments for linear contextual bandits.

problem Linear contextual bandits with adversarial corruption.
method Proposes a novel strategy called Best-of-Both-Worlds (BoBW) RealFTRL, extending RealLinExp3 and FTRL.
result Regret upper bound of $O\left(\min\left\{\frac{(\log(T))^3}{Δ_{*}} + \sqrt{\frac{C(\log(T))^3}{Δ_{*}}},\ \ \sqrt{T}(\log(T))^2 ight\} ight)$, showing effectiveness in both stochastic and adversarial environments.

Method estimates noise transition matrix from noisy labels without relying on unreliable class-posterior estimation.

problem Estimating noise transition matrix from noisy data.
method Total variation regularization to encourage distinguishable predicted probabilities.
result Consistent estimator of the noise transition matrix under mild assumptions.

We initiate the study of multi-stage episodic reinforcement learning under adversarial corruptions in both the rewards and the transition probabilities of the underlying system extending recent results for the special case of stochastic bandits. We provide a framework which modifies the aggressive exploration enjoyed b…

2019-11-20abs ↗pdf ↗

The paper tackles learning from imperfect human feedback, especially in dueling bandit problems.

problem Learning from human feedback that can be irrational or imperfect.
method Developed a Robustified Stochastic Mirror Descent for Imperfect Dueling (RoSMID) algorithm.
result Achieved nearly optimal regret for dueling bandit problems under imperfect human feedback.

This paper optimizes attacks on stochastic bandits and proposes defenses against them.

problem Optimizing adversarial attacks on stochastic bandit algorithms.
method Designs optimal attack strategies and proposes defense algorithms.
result Optimal attack strategies and defense algorithms achieve near perfect performance.

Paper shows how to use geometric median for robust SGD in high dimensions.

problem Robustifying SGD for high-dimensional optimization problems with gross corruption.
method Applying geometric median to only chosen blocks of coordinates at a time.
result Retains optimal breakdown point of 0.5 for smooth non-convex problems.

We consider high dimensional sparse regression, and develop strategies able to deal with arbitrary -- possibly, severe or coordinated -- errors in the covariance matrix XX. These may come from corrupted data, persistent experimental errors, or malicious respondents in surveys/recommender systems, etc. Such non-stochas…

2013-01-12abs ↗pdf ↗

In supervised learning one wishes to identify a pattern present in a joint distribution PP, of instances, label pairs, by providing a function ff from instances to labels that has low risk EP(y,f(x))\mathbb{E}_{P}\ell(y,f(x)). To do so, the learner is given access to nn iid samples drawn from PP. In many real world problem…

2015-04-01abs ↗pdf ↗

SGD-trained neural networks generalize well even with adversarial label noise.

problem Generalization of neural networks trained on adversarial label noise.
method Training a one-hidden-layer neural network with SGD on arbitrary width networks.
result SGD-trained networks achieve classification accuracy competitive with the best halfspace over adversarial label noise.

Efficiently learns distributions corrupted by both global and local adversarial modifications.

problem Learning distributions with both global and local adversarial corruptions.
method Develops an efficient algorithm to minimize Wasserstein distance with orthogonal projections.
result Achieves optimal risk bounds with error εk+ρ+ildeO(dkn1/(k2))\sqrt{\varepsilon k} + ρ+ ilde{O}(d\sqrt{k}n^{-1/(k \lor 2)}).

Stochastic gradient descent is a simple approach to find the local minima of a cost function whose evaluations are corrupted by noise. In this paper, we develop a procedure extending stochastic gradient descent algorithms to the case where the function is defined on a Riemannian manifold. We prove that, as in the Eucli…

2011-11-22abs ↗pdf ↗

Study cooperative bandit learning with imperfect communication, achieving near-optimal performance.

problem Real-world distributed decision-making with imperfect communication.
method Proposed decentralized algorithms for three communication scenarios: stochastic networks, random delays, and adversarially corrupted rewards.
result Achieved competitive performance and near-optimal guarantees on group regret.

Develops a comprehensive theory of corruption in supervised learning.

problem Widespread corruption in data collection affects supervised learning problems.
method Introduces a general theory of corruption using Markov kernels, distinguishing and comparing corruption types.
result Establishes a unified framework for corruption types and develops mitigation strategies.

In high dimensions, most machine learning methods are brittle to even a small fraction of structured outliers. To address this, we introduce a new meta-algorithm that can take in a base learner such as least squares or stochastic gradient descent, and harden the learner to be resistant to outliers. Our method, Sever, p…

2018-03-07abs ↗pdf ↗

New method to recover over-parameterized models corrupted during estimation.

problem Recovering statistical models corrupted after initial estimation.
method Robust estimation using over-parameterized models and redundancy.
result Stochastic gradient descent is well-suited for model repair, but sparsity is generally not repairable.

New algorithm robust to label corruptions in active learning.

problem Active learning under unknown adversarial label corruptions.
method Proposed a new active learning algorithm that is provably correct without assumptions on corruptions.
result Achieves minimax label complexity in non-corrupted setting and only requires additional labels to achieve desired accuracy in corrupted setting.

Study improves image classifier robustness to random p-norm corruptions.

problem Improving robustness of image classifiers to real-world imperceptible corruptions.
method Training and testing with random p-norm corruptions, evaluating robustness against different p-norms.
result Training with a combination of p-norm corruptions significantly improves robustness.

A method to prevent image representation collapse through data-dependent augmentation.

problem Representation collapse due to image augmentations that damage information.
method Formalizing a stochastic encoding process with a tug-of-war between corruption and preserved information, using infoMax objective.
result Learning a data-dependent distribution of augmentations to avoid representation collapse.

We report quantitative relations between corruption level and economic factors, such as country wealth and foreign investment per capita, which are characterized by a power law spanning multiple scales of wealth and investments per capita. These relations hold for diverse countries, and also remain stable over differen…

2007-05-01abs ↗pdf ↗

CUTS removes corruption from models without clean data, improving utility and security.

problem Removing corruption from models without access to clean training data.
method CUTS uses a proxy set to amplify corruption and subtract it from model weights.
result CUTS recovers a large fraction of lost utility and nearly eliminates attacks with minimal damage.