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Peter J. Liu

12 accepted papers

2025

LiPO: Listwise Preference Optimization through Learning-to-Rank

NAACL 2025long

Aligning language models (LMs) with curated human feedback is critical to control their behaviors in real-world applications. Several recent policy optimization methods, such as DPO and SLiC, serve as promising alternatives to the traditional Reinforcement Learning from Human Feedback (RLHF) approac…

Cited by 44SourcePDFScholar
2024

Scaling Exponents Across Parameterizations and Optimizers

ICML 2024poster

Robust and effective scaling of models from small to large width typically requires the precise adjustment of many algorithmic and architectural details, such as parameterization and optimizer choices. In this work, we propose a new perspective on parameterization by investigating a key assumption i…

Cited by 21SourcePDFScholar
2024

Small-scale proxies for large-scale Transformer training instabilities

ICLR 2024oral

Teams that have trained large Transformer-based models have reported training instabilities at large scale that did not appear when training with the same hyperparameters at smaller scales. Although the causes of such instabilities are of scientific interest, the amount of resources required to repr…

Cited by 79SourcePDFScholar
2024

Statistical Rejection Sampling Improves Preference Optimization

ICLR 2024poster

Improving the alignment of language models with human preferences remains an active research challenge. Previous approaches have primarily utilized online Reinforcement Learning from Human Feedback (RLHF). Recently, offline methods such as Sequence Likelihood Calibration (SLiC) and Direct Preference…

Cited by 199SourcePDFScholar
2023

Calibrating Sequence likelihood Improves Conditional Language Generation

ICLR 2023poster

Conditional language models are predominantly trained with maximum likelihood estimation (MLE), giving probability mass to sparsely observed target sequences. While MLE trained models assign high probability to plausible sequences given the context, the model probabilities often do not accurately ra…

Cited by 140SourcePDFScholar
2023

Improving the Robustness of Summarization Models by Detecting and Removing Input Noise

EMNLP 2023long findings

The evaluation of abstractive summarization models typically uses test data that is identically distributed as training data. In real-world practice, documents to be summarized may contain input noise caused by text extraction artifacts or data pipeline bugs. The robustness of model performance unde…

Cited by 0SourceScholar
2023

Investigating Efficiently Extending Transformers for Long Input Summarization

EMNLP 2023long main

While large pretrained Transformer models have proven highly capable at tackling natural language tasks, handling long sequence inputs still poses a significant challenge. One such task is long input summarization, where inputs are longer than the maximum input context of most models. Through an ext…

Cited by 0SourcecodeScholar
2023

Out-of-Distribution Detection and Selective Generation for Conditional Language Models

ICLR 2023top-25%

Machine learning algorithms typically assume independent and identically distributed samples in training and at test time (IID). Much work has shown that high-performing ML classifiers can degrade significantly and provide overly-confident, wrong classification predictions, particularly for out-of-…

Cited by 106SourcePDFScholar
2019

Likelihood Ratios for Out-of-Distribution Detection

NeurIPS 2019poster

Discriminative neural networks offer little or no performance guarantees when deployed on data not generated by the same process as the training distribution. On such out-of-distribution (OOD) inputs, the prediction may not only be erroneous, but confidently so, limiting the safe deployment of class…

2018

Beyond Word Importance: Contextual Decomposition to Extract Interactions from LSTMs

ICLR 2018oral

The driving force behind the recent success of LSTMs has been their ability to learn complex and non-linear relationships. Consequently, our inability to describe these relationships has led to LSTMs being characterized as black boxes. To this end, we introduce contextual decomposition (CD), an inte…

2017

Online and Linear-Time Attention by Enforcing Monotonic Alignments

ICML 2017poster

Recurrent neural network models with an attention mechanism have proven to be extremely effective on a wide variety of sequence-to-sequence problems. However, the fact that soft attention mechanisms perform a pass over the entire input sequence when producing each element in the output sequence prec…