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Rafael Izbicki

8 accepted papers

2025

Epistemic Uncertainty in Conformal Scores: A Unified Approach

UAI 2025

Conformal prediction methods create prediction bands with distribution-free guarantees but do not explicitly capture epistemic uncertainty, which can lead to overconfident predictions in data-sparse regions. Although recent conformal scores have been developed to address this limitation, they are ty

2025

PersonalizedUS: Interpretable Breast Cancer Risk Assessment with Local Coverage Uncertainty Quantification

AAAI 2025technical

Correctly assessing the malignancy of breast lesions identified during ultrasound examinations is crucial for effective clinical decision-making. However, the current "gold standard" relies on manual BI-RADS scoring by clinicians, often leading to unnecessary biopsies and a significant mental health…

2024

Classification under Nuisance Parameters and Generalized Label Shift in Likelihood-Free Inference

ICML 2024poster

An open scientific challenge is how to classify events with reliable measures of uncertainty, when we have a mechanistic model of the data-generating process but the distribution over both labels and latent nuisance parameters is different between train and target data. We refer to this type of dist…

2023

Simulator-Based Inference with WALDO: Confidence Regions by Leveraging Prediction Algorithms and Posterior Estimators for Inverse Problems

AISTATS 2023poster

Prediction algorithms, such as deep neural networks (DNNs), are used in many domain sciences to directly estimate internal parameters of interest in simulator-based models, especially in settings where the observations include images or complex high-dimensional data. In parallel, modern neural densi…

2021

Diagnostics for conditional density models and Bayesian inference algorithms

UAI 2021poster

There has been growing interest in the AI community for precise uncertainty quantification. Conditional density models f(y|x), where x represents potentially high-dimensional features, are an integral part of uncertainty quantification in prediction and Bayesian inference. However, it is challenging…

2020

Confidence Sets and Hypothesis Testing in a Likelihood-Free Inference Setting

ICML 2020poster

Parameter estimation, statistical tests and confidence sets are the cornerstones of classical statistics that allow scientists to make inferences about the underlying process that generated the observed data. A key question is whether one can still construct hypothesis tests and confidence sets with p…

2020

Flexible distribution-free conditional predictive bands using density estimators

AISTATS 2020poster

Conformal methods create prediction bands that control average coverage assuming solely i.i.d. data. Besides average coverage, one might also desire to control conditional coverage, that is, coverage for every new testing point. However, without strong assumptions, conditional coverage is unachievab…

2020

Validation of Approximate Likelihood and Emulator Models for Computationally Intensive Simulations

AISTATS 2020poster

Complex phenomena in engineering and the sciences are often modeled with computationally intensive feed-forward simulations for which a tractable analytic likelihood does not exist. In these cases, it is sometimes necessary to estimate an approximate likelihood or fit a fast emulator model for effic…