Search Results for author: Rafael Izbicki

Found 32 papers, 21 papers with code

Regression Trees for Fast and Adaptive Prediction Intervals

2 code implementations12 Feb 2024 Luben M. C. Cabezas, Mateus P. Otto, Rafael Izbicki, Rafael B. Stern

Our approach is based on pursuing the coarsest partition of the feature space that approximates conditional coverage.

Prediction Intervals regression +1

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

no code implementations8 Feb 2024 Luca Masserano, Alex Shen, Michele Doro, Tommaso Dorigo, Rafael Izbicki, Ann B. Lee

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.

Domain Adaptation Uncertainty Quantification +1

Distribution-Free Conformal Joint Prediction Regions for Neural Marked Temporal Point Processes

1 code implementation9 Jan 2024 Victor Dheur, Tanguy Bosser, Rafael Izbicki, Souhaib Ben Taieb

A primary objective is to generate a distribution-free joint prediction region for the arrival time and mark, with a finite-sample marginal coverage guarantee.

Conformal Prediction Point Processes +1

Expertise-based Weighting for Regression Models with Noisy Labels

no code implementations12 May 2023 Milene Regina dos Santos, Rafael Izbicki

In summary, this method offers a simple, fast, and effective solution for training regression models with noisy labels derived from diverse expert opinions.

regression

Is augmentation effective to improve prediction in imbalanced text datasets?

no code implementations20 Apr 2023 Gabriel O. Assunção, Rafael Izbicki, Marcos O. Prates

Imbalanced datasets present a significant challenge for machine learning models, often leading to biased predictions.

Data Augmentation

RFFNet: Large-Scale Interpretable Kernel Methods via Random Fourier Features

1 code implementation11 Nov 2022 Mateus P. Otto, Rafael Izbicki

Kernel methods provide a flexible and theoretically grounded approach to nonlinear and nonparametric learning.

Stochastic Optimization Variable Selection

Model interpretation using improved local regression with variable importance

1 code implementation12 Sep 2022 Gilson Y. Shimizu, Rafael Izbicki, Andre C. P. L. F. de Carvalho

A fundamental question on the use of ML models concerns the explanation of their predictions for increasing transparency in decision-making.

Decision Making regression

A unified framework for dataset shift diagnostics

2 code implementations17 May 2022 Felipe Maia Polo, Rafael Izbicki, Evanildo Gomes Lacerda Jr, Juan Pablo Ibieta-Jimenez, Renato Vicente

It is versatile, suitable for regression and classification tasks, and accommodates diverse data forms - tabular, text, or image.

Transfer Learning

A new LDA formulation with covariates

no code implementations18 Feb 2022 Gilson Shimizu, Rafael Izbicki, Denis Valle

This model allows the identification of mixed-membership clusters in discrete data and provides inference on the relationship between covariates and the abundance of these clusters.

regression Topic Models

Detecting Distributional Differences in Labeled Sequence Data with Application to Tropical Cyclone Satellite Imagery

1 code implementation4 Feb 2022 Trey McNeely, Galen Vincent, Kimberly M. Wood, Rafael Izbicki, Ann B. Lee

We prove that type I error control is guaranteed as long as the distribution of the label series is well-estimated, which is made easier by the extensive historical data for binary TC event labels.

Time Series Time Series Analysis

Hierarchical clustering: visualization, feature importance and model selection

1 code implementation30 Nov 2021 Luben M. C. Cabezas, Rafael Izbicki, Rafael B. Stern

We propose methods for the analysis of hierarchical clustering that fully use the multi-resolution structure provided by a dendrogram.

Clustering Feature Importance +1

Identifying Distributional Differences in Convective Evolution Prior to Rapid Intensification in Tropical Cyclones

no code implementations24 Sep 2021 Trey McNeely, Galen Vincent, Rafael Izbicki, Kimberly M. Wood, Ann B. Lee

Tropical cyclone (TC) intensity forecasts are issued by human forecasters who evaluate spatio-temporal observations (e. g., satellite imagery) and model output (e. g., numerical weather prediction, statistical models) to produce forecasts every 6 hours.

Likelihood-Free Frequentist Inference: Bridging Classical Statistics and Machine Learning for Reliable Simulator-Based Inference

2 code implementations8 Jul 2021 Niccolò Dalmasso, Luca Masserano, David Zhao, Rafael Izbicki, Ann B. Lee

In this work, we propose a unified and modular inference framework that bridges classical statistics and modern machine learning providing (i) a practical approach to the Neyman construction of confidence sets with frequentist finite-sample coverage for any value of the unknown parameters; and (ii) interpretable diagnostics that estimate the empirical coverage across the entire parameter space.

Open-Ended Question Answering valid

MeLIME: Meaningful Local Explanation for Machine Learning Models

1 code implementation12 Sep 2020 Tiago Botari, Frederik Hvilshøj, Rafael Izbicki, Andre C. P. L. F. de Carvalho

Additionally, we introduce modifications to standard training algorithms of local interpretable models fostering more robust explanations, even allowing the production of counterfactual examples.

BIG-bench Machine Learning counterfactual

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

2 code implementations ICML 2020 Niccolò Dalmasso, Rafael Izbicki, Ann B. Lee

In this paper, we present $\texttt{ACORE}$ (Approximate Computation via Odds Ratio Estimation), a frequentist approach to LFI that first formulates the classical likelihood ratio test (LRT) as a parametrized classification problem, and then uses the equivalence of tests and confidence sets to build confidence regions for parameters of interest.

Two-sample testing

Flexible distribution-free conditional predictive bands using density estimators

1 code implementation12 Oct 2019 Rafael Izbicki, Gilson T. Shimizu, Rafael B. Stern

In order to obtain this property, these methods require strong conditions on the dependence between the target variable and the features.

NLS: an accurate and yet easy-to-interpret regression method

1 code implementation11 Oct 2019 Victor Coscrato, Marco Henrique de Almeida Inácio, Tiago Botari, Rafael Izbicki

We develop NLS (neural local smoother), a method that is complex enough to give good predictions, and yet gives solutions that are easy to be interpreted without the need of using a separate interpreter.

BIG-bench Machine Learning regression

Distance Assessment and Hypothesis Testing of High-Dimensional Samples using Variational Autoencoders

no code implementations16 Sep 2019 Marco Henrique de Almeida Inácio, Rafael Izbicki, Bálint Gyires-Tóth

Given two distinct datasets, an important question is if they have arisen from the the same data generating function or alternatively how their data generating functions diverge from one another.

Two-sample testing

Conditional Density Estimation Tools in Python and R with Applications to Photometric Redshifts and Likelihood-Free Cosmological Inference

5 code implementations30 Aug 2019 Niccolò Dalmasso, Taylor Pospisil, Ann B. Lee, Rafael Izbicki, Peter E. Freeman, Alex I. Malz

We provide sample code in $\texttt{Python}$ and $\texttt{R}$ as well as examples of applications to photometric redshift estimation and likelihood-free cosmological inference via CDE.

Astronomy Density Estimation +2

Conditional independence testing: a predictive perspective

1 code implementation31 Jul 2019 Marco Henrique de Almeida Inácio, Rafael Izbicki, Rafael Bassi Stern

Conditional independence testing is a key problem required by many machine learning and statistics tools.

BIG-bench Machine Learning

The NN-Stacking: Feature weighted linear stacking through neural networks

1 code implementation24 Jun 2019 Victor Coscrato, Marco Henrique de Almeida Inácio, Rafael Izbicki

We show that while our approach keeps the interpretative features of Breiman's method at a local level, it leads to better predictive power, especially in datasets with large sample sizes.

Validation of Approximate Likelihood and Emulator Models for Computationally Intensive Simulations

1 code implementation27 May 2019 Niccolò Dalmasso, Ann B. Lee, Rafael Izbicki, Taylor Pospisil, Ilmun Kim, Chieh-An Lin

At the heart of our approach is a two-sample test that quantifies the quality of the fit at fixed parameter values, and a global test that assesses goodness-of-fit across simulation parameters.

Quantification under prior probability shift: the ratio estimator and its extensions

1 code implementation11 Jul 2018 Afonso Fernandes Vaz, Rafael Izbicki, Rafael Bassi Stern

The quantification problem consists of determining the prevalence of a given label in a target population.

ABC-CDE: Towards Approximate Bayesian Computation with Complex High-Dimensional Data and Limited Simulations

1 code implementation14 May 2018 Rafael Izbicki, Ann B. Lee, Taylor Pospisil

Approximate Bayesian Computation (ABC) is typically used when the likelihood is either unavailable or intractable but where data can be simulated under different parameter settings using a forward model.

Density Estimation

Converting High-Dimensional Regression to High-Dimensional Conditional Density Estimation

1 code implementation26 Apr 2017 Rafael Izbicki, Ann B. Lee

There is a growing demand for nonparametric conditional density estimators (CDEs) in fields such as astronomy and economics.

Astronomy Density Estimation +2

A Spectral Series Approach to High-Dimensional Nonparametric Regression

no code implementations1 Feb 2016 Ann B. Lee, Rafael Izbicki

We expand the unknown regression on the data in terms of the eigenfunctions of a kernel-based operator, and we take advantage of orthogonality of the basis with respect to the underlying data distribution, P, to speed up computations and tuning of parameters.

regression Vocal Bursts Intensity Prediction

Learning with many experts: model selection and sparsity

no code implementations13 May 2014 Rafael Izbicki, Rafael Bassi Stern

Next, we discuss how this loss can be used to tune a penalization which introduces sparsity in the parameters of a traditional class of models.

Model Selection

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