Research
On-device research index

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.

168,742 papers · 148 categories

Trend · papers per month

154308461615 · Jun 202019922001200920172026
48 results for good samples

New algorithm identifies good arms with fewer samples when thresholds are close.

problem Good arm identification in bandit problems with small threshold gaps.
method Proposes lil'HDoC algorithm to improve GAI under small threshold gaps.
result Sample complexity of first λ output arm is nearly identical to HDoC algorithm when thresholds are close.

New method uses reinforcement learning to sample from complex data structures efficiently.

problem Constructing reliable samples from high-dimensional polytopes for goodness-of-fit tests.
method Markov decision process and reinforcement learning for sampling.
result Demonstrated scalable tools from linear algebra for theoretical guarantees in non-linear algebra context.

We consider a novel stochastic multi-armed bandit problem called {\em good arm identification} (GAI), where a good arm is defined as an arm with expected reward greater than or equal to a given threshold. GAI is a pure-exploration problem that a single agent repeats a process of outputting an arm as soon as it is ident…

2017-10-17abs ↗pdf ↗

In biospectroscopy, suitably annotated and statistically independent samples (e. g. patients, batches, etc.) for classifier training and testing are scarce and costly. Learning curves show the model performance as function of the training sample size and can help to determine the sample size needed to train good classi…

2012-11-06abs ↗pdf ↗

We propose a novel adaptive test of goodness-of-fit, with computational cost linear in the number of samples. We learn the test features that best indicate the differences between observed samples and a reference model, by minimizing the false negative rate. These features are constructed via Stein's method, meaning th…

2017-05-22abs ↗pdf ↗

The standard approach to compressive sampling considers recovering an unknown deterministic signal with certain known structure, and designing the sub-sampling pattern and recovery algorithm based on the known structure. This approach requires looking for a good representation that reveals the signal structure, and sol…

2016-02-01abs ↗pdf ↗

We study the task of finding good local optima in combinatorial optimization problems. Although combinatorial optimization is NP-hard in general, locally optimal solutions are frequently used in practice. Local search methods however typically converge to a limited set of optima that depend on their initialization. Sam…

2018-02-25abs ↗pdf ↗

Improved Thompson Sampling reduces regret in contextual bandits and reinforcement learning.

problem Thompson Sampling's exploration is insufficient in some contexts.
method Developed Feel-Good Thompson Sampling to address exploration issues.
result Feel-Good Thompson Sampling reduces regret compared to standard Thompson Sampling.

Active deep learning classification of hyperspectral images is considered in this paper. Deep learning has achieved success in many applications, but good-quality labeled samples are needed to construct a deep learning network. It is expensive getting good labeled samples in hyperspectral images for remote sensing appl…

2016-11-30abs ↗pdf ↗

Computable Stein discrepancies have been deployed for a variety of applications, ranging from sampler selection in posterior inference to approximate Bayesian inference to goodness-of-fit testing. Existing convergence-determining Stein discrepancies admit strong theoretical guarantees but suffer from a computational co…

2018-06-20abs ↗pdf ↗

This work optimizes identifying good arms in nonparametric multi-armed bandits.

problem Efficiently identifying arms with high means in nonparametric settings.
method Combining reward-maximizing sampling with a nonparametric sequential test for anytime-valid labeling.
result Achieves minimax optimal stopping times for identifying arms above a threshold.

New algorithm for contextual dueling bandits achieves nearly optimal regret.

problem Contextual dueling bandits with feedback on preferred options.
method Proposes FGTS.CDB, a Thompson sampling algorithm for linear contextual dueling bandits.
result Achieves nearly minimax-optimal regret of ildeO(dT) ilde{\mathcal{O}}(d\sqrt T).

We propose a nonparametric statistical test for goodness-of-fit: given a set of samples, the test determines how likely it is that these were generated from a target density function. The measure of goodness-of-fit is a divergence constructed via Stein's method using functions from a Reproducing Kernel Hilbert Space. O…

2016-02-09abs ↗pdf ↗

The paper analyzes how good initial guesses affect the amount of data needed for low-rank matrix recovery.

problem Theoretical guarantee of local optimization algorithms requires excessive data to prevent spurious local minima.
method Quantifies the relationship between initial guess quality and sample complexity using restricted isometry constant.
result A linear improvement in initial guess quality leads to a constant factor improvement in sample complexity.

Improved KSD test for better detection of differences in distributions.

problem Low power of KSD test when distributions have same modes but different mixing proportions.
method Perturb the observed sample using Markov transition kernels to improve KSD test power.
result Perturbed KSD test can lead to substantially higher power than the original KSD test.

GT estimator shows convergence for Markov samples, improving i.i.d. results.

problem Estimating missing mass in Markov samples.
method Analyzed convergence of Good-Turing estimator for Markov samples, considering spectral properties of transition matrices.
result The convergence of the GT estimator for Markov samples depends on the spectral properties of the transition matrices, leading to a new minimax rate of 1/(nβ5)1/(nβ^5) for rank-2 Markov chains.

The paper establishes conditions for optimal sampling configurations on complex manifolds.

problem Finding optimal sampling configurations on complex manifolds.
method Analyzes point configurations on compact complex manifolds using tensor powers of Hermitian ample line bundles.
result Necessary and sufficient conditions for the existence of asymptotically Fekete sequences.

New tools quantify deep generative models' performance.

problem Measuring the quality-diversity trade-off in deep generative models.
method Established non-asymptotic bounds on sample complexity and introduced frontier integrals.
result Smoothed estimators improve convergence rates of divergence frontiers.

New deep learning methods improve estimation and GOF assessment for large-scale IFA.

problem Estimating and assessing goodness-of-fit for large-scale confirmatory IFA models.
method Extended deep learning algorithm for parameter estimation and simulation-based tests for GOF assessment.
result Proposed methods provide comparable estimates and detect latent dimensionality misspecification.

SGMs fail to generate samples from complex distributions even when the score function is learned well.

problem Score-based Generative Models fail to produce high-quality samples from complex distributions.
method Score-based Generative Models (SGMs) are evaluated under conditions where the score function is learned well.
result SGMs can only generate Gaussian blurring of training data points, not complex distributions.

LA-MCTS learns search space partition for black-box optimization using Monte Carlo Tree Search.

problem High-dimensional black-box optimization challenges.
method LA-MCTS recursively splits search space into regions with high/low function values, learns nonlinear partition and local models online.
result LA-MCTS achieves strong performance in black-box optimization and reinforcement learning benchmarks, especially for high-dimensional problems.

New method for identifying best arm in batched multi-armed bandit problems.

problem Identifying the best arm in multi-armed bandit problems where arms are sampled in batches.
method General linear programming framework for best arm identification in batched multi-armed bandit problems.
result Demonstrated good performance in numerical studies compared to UCB-type or Thompson sampling methods.

Bayesian neural networks show good correlation between out-of-sample performance and Bayesian evidence.

problem Improving the out-of-sample performance of Bayesian neural networks.
method Numerical sampling of Bayesian posterior, ensembling over architectures, analysis of evidence vs. model size.
result Good correlation between out-of-sample performance and Bayesian evidence; ensembling improves performance.

The paper explores learning good policies from past data in large state spaces.

problem Learning good policies from historical data in large state spaces.
method Introduces expressivity assumptions and data coverage for function approximation and algorithmic design.
result A variety of algorithms and their guarantees are presented based on assumptions and desired complexity.

Neural Architecture Search (NAS) has emerged as a promising technique for automatic neural network design. However, existing MCTS based NAS approaches often utilize manually designed action space, which is not directly related to the performance metric to be optimized (e.g., accuracy), leading to sample-inefficient exp…

2019-06-17abs ↗pdf ↗

A new method for assessing Bayesian sampling quality, PSD, is proposed and shown to be more powerful and efficient.

problem Scalability and convergence assessment of Bayesian sampling algorithms, especially for high-dimensional problems.
method Polynomial Stein Discrepancy (PSD) for measuring discrepancy between samples and posterior distributions.
result PSD detects differences in the first r moments for Gaussian targets and is more powerful and efficient than competitors.

This paper explores how effective sample size, dimensionality, and model performance are related in covariate shift adaptation.

problem Understanding the relationship between effective sample size, dimensionality, and generalization in covariate shift adaptation.
method Building a unified theory connecting effective sample size, data dimensionality, and generalization in the context of covariate shift adaptation.
result Dimensionality reduction or feature selection can increase effective sample size, supporting the practice of reducing dimensionality before covariate shift adaptation.

Improving scalability and stability of Stein discrepancies for scalable goodness-of-fit testing

problem Improving scalability and stability of Stein discrepancies for scalable goodness-of-fit testing
method Reformulating Stein discrepancy construction as an explicit SNR^2 maximisation problem
result Avoiding exponential SNR^2 collapse and achieving stable SNR^2

We propose a novel autoencoding model called Pairwise Augmented GANs. We train a generator and an encoder jointly and in an adversarial manner. The generator network learns to sample realistic objects. In turn, the encoder network at the same time is trained to map the true data distribution to the prior in latent spac…

2018-10-11abs ↗pdf ↗

We study the problem of ranking a set of items from nonactively chosen pairwise preferences where each item has feature information with it. We propose and characterize a very broad class of preference matrices giving rise to the Feature Low Rank (FLR) model, which subsumes several models ranging from the classic Bradl…

2017-02-09abs ↗pdf ↗

Reinforcement learning (RL) algorithms have made huge progress in recent years by leveraging the power of deep neural networks (DNN). Despite the success, deep RL algorithms are known to be sample inefficient, often requiring many rounds of interaction with the environments to obtain satisfactory performance. Recently,…

2018-05-19abs ↗pdf ↗

We determine the sample complexity of pure exploration bandit problems with multiple good answers. We derive a lower bound using a new game equilibrium argument. We show how continuity and convexity properties of single-answer problems ensures that the Track-and-Stop algorithm has asymptotically optimal sample complexi…

2019-02-09abs ↗pdf ↗

Efficient Reinforcement Learning usually takes advantage of demonstration or good exploration strategy. By applying posterior sampling in model-free RL under the hypothesis of GP, we propose Gaussian Process Posterior Sampling Reinforcement Learning(GPPSTD) algorithm in continuous state space, giving theoretical justif…

2018-12-11abs ↗pdf ↗

This thesis argues for learning representations from multiple similar tasks for better generalization.

problem Insufficient information in a single task for good generalization.
method Introduces the concept of an environment of a learner and uses a sample from it to learn a representation.
result Learning a representation from nn tasks reduces the number of examples required for each task by a factor of nn.

FGTSVA improves Thompson Sampling for contextual bandits with optimal variance-aware regret.

problem Optimizing regret bounds for Thompson Sampling in contextual bandits.
method Developed FGTSVA, a variance-aware Thompson Sampling algorithm for contextual bandits with a new decoupling coefficient.
result Achieved optimal regret bound of ildeO(dclogFt=1Tσt2+dc) ilde{O}(\sqrt{\mathrm{dc}\cdot\log|\mathcal{F}|\sum_{t=1}^Tσ_t^2}+\mathrm{dc}).

Adaptive importance sampling is a class of techniques for finding good proposal distributions for importance sampling. Often the proposal distributions are standard probability distributions whose parameters are adapted based on the mismatch between the current proposal and a target distribution. In this work, we prese…

2019-06-20abs ↗pdf ↗