Pengzhi Gao


2024

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LLMs Assist NLP Researchers: Critique Paper (Meta-)Reviewing
Jiangshu Du | Yibo Wang | Wenting Zhao | Zhongfen Deng | Shuaiqi Liu | Renze Lou | Henry Peng Zou | Pranav Narayanan Venkit | Nan Zhang | Mukund Srinath | Haoran Ranran Zhang | Vipul Gupta | Yinghui Li | Tao Li | Fei Wang | Qin Liu | Tianlin Liu | Pengzhi Gao | Congying Xia | Chen Xing | Cheng Jiayang | Zhaowei Wang | Ying Su | Raj Sanjay Shah | Ruohao Guo | Jing Gu | Haoran Li | Kangda Wei | Zihao Wang | Lu Cheng | Surangika Ranathunga | Meng Fang | Jie Fu | Fei Liu | Ruihong Huang | Eduardo Blanco | Yixin Cao | Rui Zhang | Philip S. Yu | Wenpeng Yin
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing

Claim: This work is not advocating the use of LLMs for paper (meta-)reviewing. Instead, wepresent a comparative analysis to identify and distinguish LLM activities from human activities. Two research goals: i) Enable better recognition of instances when someone implicitly uses LLMs for reviewing activities; ii) Increase community awareness that LLMs, and AI in general, are currently inadequate for performing tasks that require a high level of expertise and nuanced judgment.This work is motivated by two key trends. On one hand, large language models (LLMs) have shown remarkable versatility in various generative tasks such as writing, drawing, and question answering, significantly reducing the time required for many routine tasks. On the other hand, researchers, whose work is not only time-consuming but also highly expertise-demanding, face increasing challenges as they have to spend more time reading, writing, and reviewing papers. This raises the question: how can LLMs potentially assist researchers in alleviating their heavy workload?This study focuses on the topic of LLMs as NLP Researchers, particularly examining the effectiveness of LLMs in assisting paper (meta-)reviewing and its recognizability. To address this, we constructed the ReviewCritique dataset, which includes two types of information: (i) NLP papers (initial submissions rather than camera-ready) with both human-written and LLM-generated reviews, and (ii) each review comes with “deficiency” labels and corresponding explanations for individual segments, annotated by experts. Using ReviewCritique, this study explores two threads of research questions: (i) “LLMs as Reviewers”, how do reviews generated by LLMs compare with those written by humans in terms of quality and distinguishability? (ii) “LLMs as Metareviewers”, how effectively can LLMs identify potential issues, such as Deficient or unprofessional review segments, within individual paper reviews? To our knowledge, this is the first work to provide such a comprehensive analysis.

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Mixture of Diverse Size Experts
Manxi Sun | Wei Liu | Jian Luan | Pengzhi Gao | Bin Wang
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing: Industry Track

The Sparsely-Activated Mixture-of-Experts (MoE) architecture has gained popularity for scaling large language models (LLMs) due to the sub-linearly increasing computational costs. Despite its success, most of the current structure designs face the challenge that the experts share the same size such that tokens have no chance to choose the experts with the most appropriate size to generate the next token. To migrate this defect, we propose Mixture of Diverse Size Experts (MoDSE), a new MoE architecture with designed layers where experts have different sizes. Analysis on difficult token generation tasks shows that experts with different sizes give better predictions, and the routing path of the experts tends to be stable after a period of training. The diversity of experts’ size will lead to load unbalancing. To tackle this limitation, we introduce an expert-pair allocation strategy to distribute the workload evenly across the GPUs. Comprehensive evaluations across multiple benchmarks demonstrate the effectiveness of MoDSE, surpassing existing MoEs by adaptively assigning the parameter budget to experts while maintaining the same total parameter size and number of experts.

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An Empirical Study of Consistency Regularization for End-to-End Speech-to-Text Translation
Pengzhi Gao | Ruiqing Zhang | Zhongjun He | Hua Wu | Haifeng Wang
Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)

Consistency regularization methods, such as R-Drop (Liang et al., 2021) and CrossConST (Gao et al., 2023), have achieved impressive supervised and zero-shot performance in the neural machine translation (NMT) field. Can we also boost end-to-end (E2E) speech-to-text translation (ST) by leveraging consistency regularization? In this paper, we conduct empirical studies on intra-modal and cross-modal consistency and propose two training strategies, SimRegCR and SimZeroCR, for E2E ST in regular and zero-shot scenarios. Experiments on the MuST-C benchmark show that our approaches achieve state-of-the-art (SOTA) performance in most translation directions. The analyses prove that regularization brought by the intra-modal consistency, instead of the modality gap, is crucial for the regular E2E ST, and the cross-modal consistency could close the modality gap and boost the zero-shot E2E ST performance.

2023

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Improving Zero-shot Multilingual Neural Machine Translation by Leveraging Cross-lingual Consistency Regularization
Pengzhi Gao | Liwen Zhang | Zhongjun He | Hua Wu | Haifeng Wang
Findings of the Association for Computational Linguistics: ACL 2023

The multilingual neural machine translation (NMT) model has a promising capability of zero-shot translation, where it could directly translate between language pairs unseen during training. For good transfer performance from supervised directions to zero-shot directions, the multilingual NMT model is expected to learn universal representations across different languages. This paper introduces a cross-lingual consistency regularization, CrossConST, to bridge the representation gap among different languages and boost zero-shot translation performance. The theoretical analysis shows that CrossConST implicitly maximizes the probability distribution for zero-shot translation, and the experimental results on both low-resource and high-resource benchmarks show that CrossConST consistently improves the translation performance. The experimental analysis also proves that CrossConST could close the sentence representation gap and better align the representation space. Given the universality and simplicity of CrossConST, we believe it can serve as a strong baseline for future multilingual NMT research.

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Learning Multilingual Sentence Representations with Cross-lingual Consistency Regularization
Pengzhi Gao | Liwen Zhang | Zhongjun He | Hua Wu | Haifeng Wang
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing: Industry Track

Multilingual sentence representations are the foundation for similarity-based bitext mining, which is crucial for scaling multilingual neural machine translation (NMT) system to more languages. In this paper, we introduce MuSR: a one-for-all Multilingual Sentence Representation model that supports 223 languages. Leveraging billions of English-centric parallel corpora, we train a multilingual Transformer encoder, coupled with an auxiliary Transformer decoder, by adopting a multilingual NMT framework with CrossConST, a cross-lingual consistency regularization technique proposed in Gao et al. (2023). Experimental results on multilingual similarity search and bitext mining tasks show the effectiveness of our approach. Specifically, MuSR achieves superior performance over LASER3 (Heffernan et al., 2022) which consists of 148 independent multilingual sentence encoders.

2022

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Bi-SimCut: A Simple Strategy for Boosting Neural Machine Translation
Pengzhi Gao | Zhongjun He | Hua Wu | Haifeng Wang
Proceedings of the 2022 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

We introduce Bi-SimCut: a simple but effective training strategy to boost neural machine translation (NMT) performance. It consists of two procedures: bidirectional pretraining and unidirectional finetuning. Both procedures utilize SimCut, a simple regularization method that forces the consistency between the output distributions of the original and the cutoff sentence pairs. Without leveraging extra dataset via back-translation or integrating large-scale pretrained model, Bi-SimCut achieves strong translation performance across five translation benchmarks (data sizes range from 160K to 20.2M): BLEU scores of 31.16 for ende and 38.37 for deen on the IWSLT14 dataset, 30.78 for ende and 35.15 for deen on the WMT14 dataset, and 27.17 for zhen on the WMT17 dataset. SimCut is not a new method, but a version of Cutoff (Shen et al., 2020) simplified and adapted for NMT, and it could be considered as a perturbation-based method. Given the universality and simplicity of Bi-SimCut and SimCut, we believe they can serve as strong baselines for future NMT research.

2021

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Mixup Decoding for Diverse Machine Translation
Jicheng Li | Pengzhi Gao | Xuanfu Wu | Yang Feng | Zhongjun He | Hua Wu | Haifeng Wang
Findings of the Association for Computational Linguistics: EMNLP 2021

Diverse machine translation aims at generating various target language translations for a given source language sentence. To leverage the linear relationship in the sentence latent space introduced by the mixup training, we propose a novel method, MixDiversity, to generate different translations for the input sentence by linearly interpolating it with different sentence pairs sampled from the training corpus during decoding. To further improve the faithfulness and diversity of the translations, we propose two simple but effective approaches to select diverse sentence pairs in the training corpus and adjust the interpolation weight for each pair correspondingly. Moreover, by controlling the interpolation weight, our method can achieve the trade-off between faithfulness and diversity without any additional training, which is required in most of the previous methods. Experiments on WMT’16 en-ro, WMT’14 en-de, and WMT’17 zh-en are conducted to show that our method substantially outperforms all previous diverse machine translation methods.

2020

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A Data-Centric Framework for Composable NLP Workflows
Zhengzhong Liu | Guanxiong Ding | Avinash Bukkittu | Mansi Gupta | Pengzhi Gao | Atif Ahmed | Shikun Zhang | Xin Gao | Swapnil Singhavi | Linwei Li | Wei Wei | Zecong Hu | Haoran Shi | Xiaodan Liang | Teruko Mitamura | Eric Xing | Zhiting Hu
Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing: System Demonstrations

Empirical natural language processing (NLP) systems in application domains (e.g., healthcare, finance, education) involve interoperation among multiple components, ranging from data ingestion, human annotation, to text retrieval, analysis, generation, and visualization. We establish a unified open-source framework to support fast development of such sophisticated NLP workflows in a composable manner. The framework introduces a uniform data representation to encode heterogeneous results by a wide range of NLP tasks. It offers a large repository of processors for NLP tasks, visualization, and annotation, which can be easily assembled with full interoperability under the unified representation. The highly extensible framework allows plugging in custom processors from external off-the-shelf NLP and deep learning libraries. The whole framework is delivered through two modularized yet integratable open-source projects, namely Forte (for workflow infrastructure and NLP function processors) and Stave (for user interaction, visualization, and annotation).