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Linfeng Song

38 accepted papers

2026

CDE: Curiosity-Driven Exploration for Efficient Reinforcement Learning in Large Language Models

ICLR 2026poster

Reinforcement Learning with Verifiable Rewards (RLVR) is a powerful paradigm for enhancing the reasoning ability of Large Language Models (LLMs). Yet current RLVR methods often explore poorly, leading to premature convergence and entropy collapse. Moreover, they tend to produce poorly calibrated pol…

Cited by 0SourcecodeScholar
2026

DeepMath-103K: A Large-Scale, Challenging, Decontaminated, and Verifiable Mathematical Dataset for Advancing Reasoning

ICLR 2026poster

Reinforcement learning (RL) with large language models shows promise in complex reasoning. However, its progress is hindered by the lack of large-scale training data that is sufficiently challenging, contamination-free and verifiable. To this end, we introduce DeepMath-103K, a large-scale mathematic…

Cited by 0SourcecodeScholar
2025

Do NOT Think That Much for 2+3=? On the Overthinking of Long Reasoning Models

ICML 2025poster

The remarkable performance of long reasoning models can be attributed to their ability to emulate human-like long-time thinking during inference. These models employ extended chain-of-thought (CoT) processes, exploring multiple strategies to enhance problem-solving capabilities. However, a critical…

2025

Don’t Get Lost in the Trees: Streamlining LLM Reasoning by Overcoming Tree Search Exploration Pitfalls

ACL 2025long

Recent advancements in tree search algorithms guided by verifiers have significantly enhanced the reasoning capabilities of large language models (LLMs), but at the cost of increased computational resources. In this work, we identify two key challenges contributing to this inefficiency: over-explora…

2025

Entropy Guided Extrapolative Decoding to Improve Factuality in Large Language Models

COLING 2025main

Large language models (LLMs) exhibit impressive natural language capabilities but suffer from hallucination – generating content ungrounded in the realities of training data. Recent work has focused on decoding techniques to improve factuality in decoding by leveraging LLMs’ hierarchical representat…

2025

Improving LLM General Preference Alignment via Optimistic Online Mirror Descent

NeurIPS 2025spotlight

Reinforcement learning from human feedback (RLHF) has demonstrated remarkable effectiveness in aligning large language models (LLMs) with human preferences. Many existing alignment approaches rely on the Bradley-Terry (BT) model assumption, which assumes the existence of a ground-truth reward for ea…

Cited by 0SourceScholar
2025

Iterative Nash Policy Optimization: Aligning LLMs with General Preferences via No-Regret Learning

ICLR 2025oral

Reinforcement Learning with Human Feedback (RLHF) has achieved great success in aligning large language models (LLMs) with human preferences. Prevalent RLHF approaches are reward-based, following the Bradley-Terry (BT) model assumption, which may not fully capture the complexity of human preferences…

Cited by 4SourcePDFScholar
2025

LiteSearch: Efficient Tree Search with Dynamic Exploration Budget for Math Reasoning

AAAI 2025technical

Recent research suggests that tree search algorithms (e.g. Monte Carlo Tree Search) can dramatically boost LLM performance on complex mathematical reasoning tasks. However, they often require more than 10 times the computational resources of greedy decoding due to wasteful search strategies, making…

Cited by 0SourcePDFScholar
2025

MPS-Prover: Advancing Stepwise Theorem Proving by Multi-Perspective Search and Data Curation

NeurIPS 2025poster

Automated Theorem Proving (ATP) in formal languages remains a formidable challenge in AI, demanding rigorous logical deduction and navigating vast search spaces. While large language models (LLMs) have shown promising performance, existing stepwise provers often suffer from biased search guidance, l…

Cited by 0SourceScholar
2025

SR-LLM: Rethinking the Structured Representation in Large Language Model

ACL 2025long

Structured representations, exemplified by Abstract Meaning Representation (AMR), have long been pivotal in computational linguistics. However, their role remains ambiguous in the Large Language Models (LLMs) era. Initial attempts to integrate structured representation into LLMs via a zero-shot sett…

Cited by 0SourcePDFScholar
2025

Thoughts Are All Over the Place: On the Underthinking of Long Reasoning Models

NeurIPS 2025spotlight

Long reasoning models (LRMs) such as OpenAI's o1 and DeepSeek's R1 have demonstrated remarkable abilities in complex reasoning tasks by scaling test-time compute and exhibiting human-like deep thinking. However, we identify a phenomenon we term underthinking, where LRMs frequently switch between dif…

Cited by 0SourcecodeScholar
2024

A Knowledge Plug-and-Play Test Bed for Open-domain Dialogue Generation

COLING 2024main

Knowledge-based, open-domain dialogue generation aims to build chit-chat systems that talk to humans using mined support knowledge. Many types and sources of knowledge have previously been shown to be useful as support knowledge. Even in the era of large language models, response generation grounded…

2024

Improving LLM Generations via Fine-Grained Self-Endorsement

ACL 2024findings

This work studies mitigating fact-conflicting hallucinations for large language model (LLM) at inference time.Particularly, we propose a self-endorsement framework that leverages the fine-grained fact-level comparisons across multiple sampled responses.Compared with prior ensemble methods (e.g., sel…

Cited by 2SourcePDFScholar
2024

Mitigating Catastrophic Forgetting in Large Language Models with Self-Synthesized Rehearsal

ACL 2024long

Large language models (LLMs) suffer from catastrophic forgetting during continual learning. Conventional rehearsal-based methods rely on previous training data to retain the model’s ability, which may not be feasible in real-world applications. When conducting continual learning based on a publicly-…

2024

Response Enhanced Semi-supervised Dialogue Query Generation

AAAI 2024technical

Leveraging vast and continually updated knowledge from the Internet has been considered an important ability for a dialogue system. Therefore, the dialogue query generation task is proposed for generating search queries from dialogue histories, which will be submitted to a search engine for retrievi…

2024

Self-Alignment for Factuality: Mitigating Hallucinations in LLMs via Self-Evaluation

ACL 2024long

Despite showing impressive abilities, large language models (LLMs) often struggle with factual inaccuracies, i.e., ”hallucinations”, even when they hold relevant knowledge. To mitigate these hallucinations, current approaches typically necessitate high-quality human factuality annotations. In this w…

Cited by 35SourcePDFScholar
2024

The Trickle-down Impact of Reward Inconsistency on RLHF

ICLR 2024poster

Standard practice within Reinforcement Learning from Human Feedback (RLHF) involves optimizing against a Reward Model (RM), which itself is trained to reflect human preferences for desirable generations. A notable subject that is understudied is the (in-)consistency of RMs --- whether they can recog…

2024

Toward Self-Improvement of LLMs via Imagination, Searching, and Criticizing

NeurIPS 2024poster

Despite the impressive capabilities of Large Language Models (LLMs) on various tasks, they still struggle with scenarios that involves complex reasoning and planning. Self-correction and self-learning emerge as viable solutions, employing strategies that allow LLMs to refine their outputs and learn…

2023

A Survey on Zero Pronoun Translation

ACL 2023long

Zero pronouns (ZPs) are frequently omitted in pro-drop languages (e.g. Chinese, Hungarian, and Hindi), but should be recalled in non-pro-drop languages (e.g. English). This phenomenon has been studied extensively in machine translation (MT), as it poses a significant challenge for MT systems due to…

2023

Bi-level Finetuning with Task-dependent Similarity Structure for Low-resource Training

ACL 2023findings

Training a large language model in low-resource settings is challenging since they are susceptible to overfitting with limited generalization abilities. Previous work addresses this issue by approaches such as tunable parameters reduction or data augmentation. However, they either limit the trained…

2023

Domain Adaptation for Conversational Query Production with the RAG Model Feedback

EMNLP 2023long findings

Conversational query production is an emerging fundamental task for the dialogue system, where search queries are generated to explore the vast and continually updating knowledge from a search engine. To accelerate this line of research, previous studies have released several datasets with human-ann…

Cited by 0SourceScholar
2023

SafeConv: Explaining and Correcting Conversational Unsafe Behavior

ACL 2023long

One of the main challenges open-domain end-to-end dialogue systems, or chatbots, face is the prevalence of unsafe behavior, such as toxic languages and harmful suggestions. However, existing dialogue datasets do not provide enough annotation to explain and correct such unsafe behavior. In this work,…

2022

Augmenting Multi-Turn Text-to-SQL Datasets with Self-Play

EMNLP 2022finding

The task of context-dependent text-to-SQL aims to convert multi-turn user utterances to formal SQL queries. This is a challenging task due to both the scarcity of training data from which to learn complex contextual dependencies and to generalize to unseen databases. In this paper we explore augment…

2022

Cross-lingual Text-to-SQL Semantic Parsing with Representation Mixup

EMNLP 2022finding

We focus on the cross-lingual Text-to-SQL semantic parsing task,where the parsers are expected to generate SQL for non-English utterances based on English database schemas.Intuitively, English translation as side information is an effective way to bridge the language gap,but noise introduced by the…

2022

Getting the Most out of Simile Recognition

EMNLP 2022finding

Simile recognition involves two subtasks: simile sentence classification that discriminates whether a sentence contains simile, and simile component extraction that locates the corresponding objects (i.e., tenors and vehicles).Recent work ignores features other than surface strings and suffers from…

2022

GuoFeng: A Benchmark for Zero Pronoun Recovery and Translation

EMNLP 2022main

The phenomenon of zero pronoun (ZP) has attracted increasing interest in the machine translation (MT) community due to its importance and difficulty. However, previous studies generally evaluate the quality of translating ZPs with BLEU scores on MT testsets, which is not expressive or sensitive enou…

2022

Hierarchical Context Tagging for Utterance Rewriting

AAAI 2022technical

Utterance rewriting aims to recover coreferences and omitted information from the latest turn of a multi-turn dialogue. Recently, methods that tag rather than linearly generate sequences have proven stronger in both in- and out-of-domain rewriting settings. This is due to a tagger's smaller search s…

2022

Learning a Grammar Inducer from Massive Uncurated Instructional Videos

EMNLP 2022main

Video-aided grammar induction aims to leverage video information for finding more accurate syntactic grammars for accompanying text. While previous work focuses on building systems for inducing grammars on text that are well-aligned with video content, we investigate the scenario, in which text and…

2022

Variational Graph Autoencoding as Cheap Supervision for AMR Coreference Resolution

ACL 2022long

Coreference resolution over semantic graphs like AMRs aims to group the graph nodes that represent the same entity. This is a crucial step for making document-level formal semantic representations. With annotated data on AMR coreference resolution, deep learning approaches have recently shown great…

2021

A Structure Self-Aware Model for Discourse Parsing on Multi-Party Dialogues

IJCAI 2021poster

Conversational discourse structures aim to describe how a dialogue is organized, thus they are helpful for dialogue understanding and response generation. This paper focuses on predicting discourse dependency structures for multi-party dialogues. Previous work adopts incremental methods that take th…

2021

Domain-Adaptive Pretraining Methods for Dialogue Understanding

ACL 2021short

Language models like BERT and SpanBERT pretrained on open-domain data have obtained impressive gains on various NLP tasks. In this paper, we probe the effectiveness of domain-adaptive pretraining objectives on downstream tasks. In particular, three objectives, including a novel objective focusing on…

Cited by 25SourcePDFScholar
2021

Instance-adaptive training with noise-robust losses against noisy labels

EMNLP 2021main

In order to alleviate the huge demand for annotated datasets for different tasks, many recent natural language processing datasets have adopted automated pipelines for fast-tracking usable data. However, model training with such datasets poses a challenge because popular optimization objectives are…

Cited by 10SourcePDFScholar
2021

RAST: Domain-Robust Dialogue Rewriting as Sequence Tagging

EMNLP 2021main

The task of dialogue rewriting aims to reconstruct the latest dialogue utterance by copying the missing content from the dialogue context. Until now, the existing models for this task suffer from the robustness issue, i.e., performances drop dramatically when testing on a different dataset. We addre…

2021

Video-aided Unsupervised Grammar Induction

NAACL 2021long

We investigate video-aided grammar induction, which learns a constituency parser from both unlabeled text and its corresponding video. Existing methods of multi-modal grammar induction focus on grammar induction from text-image pairs, with promising results showing that the information from static i…