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Nan Lu

9 accepted papers

2023

Generalizing Importance Weighting to A Universal Solver for Distribution Shift Problems

NeurIPS 2023spotlight

Distribution shift (DS) may have two levels: the distribution itself changes, and the support (i.e., the set where the probability density is non-zero) also changes. When considering the support change between the training and test distributions, there can be four cases: (i) they exactly match; (ii)…

2022

Federated Learning from Only Unlabeled Data with Class-conditional-sharing Clients

ICLR 2022poster

Supervised federated learning (FL) enables multiple clients to share the trained model without sharing their labeled data. However, potential clients might even be reluctant to label their own data, which could limit the applicability of FL in practice. In this paper, we show the possibility of unsu…

2021

Binary Classification from Multiple Unlabeled Datasets via Surrogate Set Classification

ICML 2021spotlight

To cope with high annotation costs, training a classifier only from weakly supervised data has attracted a great deal of attention these days. Among various approaches, strengthening supervision from completely unsupervised classification is a promising direction, which typically employs class prior…

2021

Pointwise Binary Classification with Pairwise Confidence Comparisons

ICML 2021spotlight

To alleviate the data requirement for training effective binary classifiers in binary classification, many weakly supervised learning settings have been proposed. Among them, some consider using pairwise but not pointwise labels, when pointwise labels are not accessible due to privacy, confidentiali…

Cited by 33SourcePDFScholar
2020

Mitigating Overfitting in Supervised Classification from Two Unlabeled Datasets: A Consistent Risk Correction Approach

AISTATS 2020poster

The recently proposed unlabeled-unlabeled (UU) classification method allows us to train a binary classifier only from two unlabeled datasets with different class priors. Since this method is based on the empirical risk minimization, it works as if it is a supervised classification method, compatible…

Cited by 71SourcePDFScholar
2020

Rethinking Importance Weighting for Deep Learning under Distribution Shift

NeurIPS 2020spotlight

Under distribution shift (DS) where the training data distribution differs from the test one, a powerful technique is importance weighting (IW) which handles DS in two separate steps: weight estimation (WE) estimates the test-over-training density ratio and weighted classification (WC) trains the cl…

2019

On the Minimal Supervision for Training Any Binary Classifier from Only Unlabeled Data

ICLR 2019poster

Empirical risk minimization (ERM), with proper loss function and regularization, is the common practice of supervised classification. In this paper, we study training arbitrary (from linear to deep) binary classifier from only unlabeled (U) data by ERM. We prove that it is impossible to estimate the…