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Kehai Chen

63 accepted papers

2026

CRPO: Character-centric Group Relative Policy Optimization for Role-aware Reasoning in Role-playing Agents

ICML 2026poster

Recent advancements in Reinforcement Learning (RL), particularly Group Relative Policy Optimization (GRPO), have significantly enhanced the reasoning capabilities of Large Language Models. However, applying these problem-centric optimization methods to role-playing agents often leads to a loss of ch…

Cited by 0SourceScholar
2026

Culture In a Frame: C$^3$B as a Comic-Based Benchmark for Multimodal Culturally Awareness

ICLR 2026poster

Cultural awareness capabilities has emerged as a critical capability for Multimodal Large Language Models (MLLMs). However, current benchmarks lack progressed difficulty in their task design and are deficient in cross-lingual tasks. Moreover, current benchmarks often use real-world images. Each real…

Cited by 0SourceScholar
2026

Decoupling Skeleton and Flesh: Efficient Multimodal Table Reasoning with Disentangled Alignment and Structure-aware Guidance

ICML 2026spotlight

Reasoning over table images remains challenging for Large Vision-Language Models (LVLMs) due to complex layouts and tightly coupled structure–content information. Existing solutions often depend on expensive supervised training, reinforcement learning, or external tools, limiting efficiency and scal…

Cited by 0SourceScholar
2026

DocOS: A Benchmark for Proactive Document-Guided Actions in GUI Agents

ICML 2026poster

While Graphical User Interface (GUI) agents have shown promising performance in automated device interaction, they primarily depend on static parametric knowledge from pre-training or instruction tuning. This reliance fundamentally limits their ability to handle long-tailed tasks that require explic…

Cited by 0SourceScholar
2026

Dynamics Within Latent Chain-of-Thought: An Empirical Study of Causal Structure

ICML 2026poster

Latent or continuous chain-of-thought methods replace explicit textual rationales with a number of internal latent steps, but these intermediate computations are difficult to evaluate beyond correlation-based probes. In this paper, we view latent chain-of-thought as a manipulable causal process in r…

Cited by 0SourceScholar
2026

Evaluating and Improving Cultural Awareness of Reward Models for LLM Alignment

ICLR 2026poster

Reward models (RMs) are crucial for aligning large language models (LLMs) with diverse cultures. Consequently, evaluating their cultural awareness is essential for further advancing global alignment of LLMs. However, existing RM evaluations fall short in assessing cultural awareness due to the scarc…

Cited by 0SourceScholar
2026

Evaluating and Steering Modality Preferences in Multi-modal LLMs

ICML 2026poster

Multi-modal large language models (MLLMs) have achieved remarkable success on complex multi-modal tasks. However, it remains insufficiently explored whether they exhibit \textit{modality preference}, a tendency to favor one modality over another when processing multi-modal contexts. To study this qu…

Cited by 0SourceScholar
2026

LoCoT2V-Bench: Benchmarking Long-Form and Complex Text-to-Video Generation

ICML 2026poster

Recent advances in text-to-video generation have achieved impressive performance on short clips, yet evaluating long-form generation under complex textual inputs remains a significant challenge. In response to this challenge, we present LoCoT2V-Bench, a benchmark for long video generation (LVG) feat…

Cited by 0SourceScholar
2026

Long-form RewardBench: Evaluating Reward Models for Long-form Generation

AAAI 2026technical

The widespread adoption of reinforcement learning-based alignment highlights the growing importance of reward models. Various benchmarks have been built to evaluate reward models in various domains and scenarios. However, a significant gap remains in assessing reward models for long-form generation,

Cited by 0SourcePDFScholar
2026

Lost in Benchmarks? Rethinking Large Language Model Benchmarking with Item Response Theory

AAAI 2026technical

The evaluation of large language models (LLMs) via benchmarks is widespread, yet inconsistencies between different leaderboards and poor separability among top models raise concerns about their ability to accurately reflect authentic model capabilities. This paper provides a critical analysis of ben

Cited by 0SourcePDFScholar
2026

Mitigating Translationese Bias in Multilingual LLM-as-a-Judge via Disentangled Information Bottleneck

ICML 2026poster

Large language models (LLMs) have emerged as a standard paradigm for automated multilingual evaluation, yet exhibit systematic biases. In this paper, we identify ``translationese bias'', in which LLMs systematically favor machine-translated text over human-authored references, and this bias is parti…

Cited by 0SourceScholar
2026

The Secret Engine Behind RLHF: It's Contarstive Learning All Along

ICML 2026poster

Alignment of large language models (LLMs) with human values has recently garnered significant attention, with prominent examples including the canonical yet costly Reinforcement Learning from Human Feedback (RLHF) and the simple Direct Preference Optimization (DPO). In this work, we demonstrate that…

Cited by 0SourceScholar
2026

User-Aware Active Knowledge Acquisition for Emotional Support Dialogue

ICML 2026poster

Emotional support plays an important role in dialogue systems, and its success depends on adapting to a user’s evolving and implicit needs across multi-turn interactions while leveraging the strong reasoning capacity of large language models (LLMs). However, since user needs are often weakly supervi…

Cited by 0SourceScholar
2025

A Survey on the Feedback Mechanism of LLM-based AI Agents

IJCAI 2025

Large language models (LLMs) are increasingly being adopted to develop general-purpose AI agents. However, it remains challenging for these LLM-based AI agents to efficiently learn from feedback and iteratively optimize their strategies. To address this challenge, tremendous efforts have been dedica

2025

Benchmarking LLMs for Translating Classical Chinese Poetry: Evaluating Adequacy, Fluency, and Elegance

EMNLP 2025

Large language models (LLMs) have shown remarkable performance in general translation tasks. However, the increasing demand for high-quality translations that are not only adequate but also fluent and elegant. To assess the extent to which current LLMs can meet these demands, we introduce a suitable

2025

Benchmarking and Improving Large Vision-Language Models for Fundamental Visual Graph Understanding and Reasoning

ACL 2025long

Large Vision-Language Models (LVLMs) have demonstrated remarkable performance across diverse tasks. Despite great success, recent studies show that LVLMs encounter substantial limitations when engaging with visual graphs. To study the reason behind these limitations, we propose VGCure, a comprehensi…

2025

Efficient Safety Alignment of Large Language Models via Preference Re-ranking and Representation-based Reward Modeling

ACL 2025long

Reinforcement Learning (RL) algorithms for safety alignment of Large Language Models (LLMs), such as Direct Preference Optimization (DPO), encounter the challenge of distribution shift. Current approaches typically address this issue through online sampling from the target policy, which requires sig…

Cited by 0SourcePDFScholar
2025

Exploring the Translation Mechanism of Large Language Models

NeurIPS 2025poster

While large language models (LLMs) demonstrate remarkable success in multilingual translation, their internal core translation mechanisms, even at the fundamental word level, remain insufficiently understood. To address this critical gap, this work introduces a systematic framework for interpreting…

Cited by 0SourceScholar
2025

From Awareness to Adaptability: Enhancing Tool Utilization for Scientific Reasoning

ACL 2025finding

As large language models (LLMs) are increasingly applied to complex scientific problem-solving, their effectiveness is often limited by unconscious or failed tool usage. To address this issue, we introduce the Tool-Awareness Training (TAT) method, designed to enhance scientific reasoning. This appro…

2025

Generative Reward Modeling via Synthetic Criteria Preference Learning

ACL 2025long

Generative Reward Models (GenRMs) leverage synthesized Chains of Thought (CoT) to reduce the need for massive labeled data, but this approach introduces risks of overoptimization due to the inability to guarantee the correctness of the CoTs. Identifying and optimizing unexpected behaviors within the…

2025

Generator-Assistant Stepwise Rollback Framework for Large Language Model Agent

EMNLP 2025

Large language model (LLM) agents typically adopt a step-by-step reasoning framework, in which they interleave the processes of thinking and acting to accomplish the given task. However, this paradigm faces a deep-rooted one-pass issue whereby each generated intermediate thought is plugged into the

2025

InImageTrans: Multimodal LLM-based Text Image Machine Translation

ACL 2025finding

Multimodal large language models (MLLMs) have shown remarkable capabilities across various downstream tasks. However, when MLLMs are transferred to the text image machine translation (TiMT) task, preliminary experiments reveal that MLLMs suffer from serious repetition and omission hallucinations. To…

2025

LLM-based Translation Inference with Iterative Bilingual Understanding

ACL 2025finding

The remarkable understanding and generation capabilities of large language models (LLMs) have greatly improved translation performance. However, incorrect understanding of the sentence to be translated can degrade translation quality. To address this issue, we proposed a novel Iterative Bilingual Un…

2025

Look Before You Leap: Enhance Attention and Vigilance Regarding Harmful Content with GuidelineLLM

AAAI 2025technical

Despite being empowered with alignment mechanisms, large language models (LLMs) are increasingly vulnerable to emerging jailbreak attacks that can compromise their alignment mechanisms. This vulnerability poses significant risks to real-world applications. Existing work faces challenges in both tra…

2025

MASTER: Enhancing Large Language Model via Multi-Agent Simulated Teaching

NeurIPS 2025poster

Instruction fine-tuning is crucial in NLP tasks, enhancing pretrained models' instruction-following capabilities and task-specific performance. However, obtaining high-quality fine-tuning data for large models is challenging due to data collection difficulties and high production costs. To address t…

Cited by 0SourceScholar
2025

MDIT-Bench: Evaluating the Dual-Implicit Toxicity in Large Multimodal Models

ACL 2025finding

The widespread use of Large Multimodal Models (LMMs) has raised concerns about model toxicity. However, current research mainly focuses on explicit toxicity, with less attention to some more implicit toxicity regarding prejudice and discrimination. To address this limitation, we introduce a subtler…

2025

Make Imagination Clearer! Stable Diffusion-based Visual Imagination for Multimodal Machine Translation

ACL 2025long

Visual information has been introduced for enhancing machine translation (MT), and its effectiveness heavily relies on the availability of large amounts of bilingual parallel sentence pairs with manual image annotations. In this paper, we introduce a stable diffusion-based imagination network into a…

2025

Memory-augmented Query Reconstruction for LLM-based Knowledge Graph Reasoning

ACL 2025finding

Large language models (LLMs) have achieved remarkable performance on knowledge graph question answering (KGQA) tasks by planning and interacting with knowledge graphs. However, existing methods often confuse tool utilization with knowledge reasoning, harming readability of model outputs and giving r…

2025

Merge then Realign: Simple and Effective Modality-Incremental Continual Learning for Multimodal LLMs

EMNLP 2025

Recent advances in Multimodal Large Language Models (MLLMs) have enhanced their versatility as they integrate a growing number of modalities. Considering the heavy cost of training MLLMs, it is efficient to reuse the existing ones and extend them to more modalities through Modality-incremental Conti

Cited by 0SourcePDFScholar
2025

MoDification: Mixture of Depths Made Easy

NAACL 2025long

Long-context efficiency has recently become a trending topic in serving large language models (LLMs). And mixture of depths (MoD) is proposed as a perfect fit to bring down both latency and memory. In this paper, however, we discover that MoD can barely transform existing LLMs without costly trainin…

Cited by 2SourcePDFScholar
2025

ORPP: Self-Optimizing Role-playing Prompts to Enhance Language Model Capabilities

EMNLP 2025

High-quality prompts are crucial for eliciting outstanding performance from large language models (LLMs) on complex tasks. Existing research has explored model-driven strategies for prompt optimization. However, these methods often suffer from high computational overhead or require strong optimizati

Cited by 0SourcePDFScholar
2025

The Rise of Darkness: Safety-Utility Trade-Offs in Role-Playing Dialogue Agents

ACL 2025finding

Large Language Models (LLMs) have made remarkable advances in role-playing dialogue agents, demonstrating their utility in character simulations. However, it remains challenging for these agents to balance character portrayal utility with content safety because this essential character simulation of…

2025

Thinking in Character: Advancing Role-Playing Agents with Role-Aware Reasoning

NeurIPS 2025poster

The advancement of Large Language Models (LLMs) has spurred significant interest in Role-Playing Agents (RPAs) for applications such as emotional companionship and virtual interaction. However, recent RPAs are often built on explicit dialogue data, lacking deep, human-like internal thought processes…

Cited by 0SourceScholar
2025

Tool learning via Inference-time Scaling and Cycle Verifier

ACL 2025finding

In inference-time scaling, Chain-of-Thought (CoT) plays a crucial role in enabling large language models (LLMs) to exhibit reasoning capabilities. However, in many scenarios, high-quality CoT data is scarce or even unavailable. In such cases, STaR-like methods can help LLMs synthesize CoT based on u…

2025

Understanding the RoPE Extensions of Long-Context LLMs: An Attention Perspective

COLING 2025main

Enabling LLMs to handle lengthy context is currently a research hotspot. Most LLMs are built upon rotary position embedding (RoPE), a popular position encoding method. Therefore, a prominent path is to extrapolate the RoPE trained on comparably short texts to far longer texts. A heavy bunch of effor…

Cited by 7SourcePDFScholar
2025

Unified Transferability Metrics for Time Series Foundation Models

NeurIPS 2025poster

With the increasing number of time series pre-trained models, designing transferability evaluation metrics for time series has become an urgent problem to address. While transferability evaluation has been extensively studied in computer vision, we aim to address a critical gap by developing tailor…

Cited by 0SourceScholar
2025

XIFBench: Evaluating Large Language Models on Multilingual Instruction Following

NeurIPS 2025poster

Large Language Models (LLMs) have demonstrated remarkable instruction-following capabilities across various applications. However, their performance in multilingual settings lacks systematic investigation, with existing evaluations lacking fine-grained constraint analysis across diverse linguistic c…

Cited by 0SourcecodeScholar
2025

ZigZagKV: Dynamic KV Cache Compression for Long-context Modeling based on Layer Uncertainty

COLING 2025main

Large Language models (LLMs) have become a research hotspot. To accelerate the inference of LLMs, storing computed caches in memory has become the standard technique. However, as the inference length increases, growing KV caches might lead to out-of-memory issues. Many existing methods address this…

Cited by 0SourcePDFScholar
2024

Adaptive Feature-based Low-Rank Compression of Large Language Models via Bayesian Optimization

EMNLP 2024finding

In recent years, large language models (LLMs) have driven advances in natural language processing. Still, their growing scale has increased the computational burden, necessitating a balance between efficiency and performance. Low-rank compression, a promising technique, reduces non-essential paramet…

2024

Context Consistency between Training and Inference in Simultaneous Machine Translation

ACL 2024long

Simultaneous Machine Translation (SiMT) aims to yield a real-time partial translation with a monotonically growing source-side context.However, there is a counterintuitive phenomenon about the context usage between training and inference: *e.g.*, in wait-k inference, model consistently trained with…

Cited by 1SourcePDFScholar
2024

DUAL-REFLECT: Enhancing Large Language Models for Reflective Translation through Dual Learning Feedback Mechanisms

ACL 2024short

Recently, large language models (LLMs) enhanced by self-reflection have achieved promising performance on machine transla004 tion. The key idea is guiding LLMs to generate translation with human-like feedback. However, existing self-reflection methods lack effective feedback information, limiting th…

2024

Dynamic Planning for LLM-based Graphical User Interface Automation

EMNLP 2024finding

The advent of large language models (LLMs) has spurred considerable interest in advancing autonomous LLMs-based agents, particularly in intriguing applications within smartphone graphical user interfaces (GUIs). When presented with a task goal, these agents typically emulate human actions within a G…

2024

Efficient Domain Adaptation for Non-Autoregressive Machine Translation

ACL 2024findings

Domain adaptation remains a challenge in the realm of Neural Machine Translation (NMT), even in the era of large language models (LLMs). Existing non-parametric approaches like nearest neighbor machine translation have made small Autoregressive Translation (AT) models achieve efficient domain genera…

2024

On the Hallucination in Simultaneous Machine Translation

ACL 2024short

It is widely known that hallucination is a critical issue in Simultaneous Machine Translation (SiMT) due to the absence of source-side information. While many efforts have been made to enhance performance for SiMT, few of them attempt to understand and analyze hallucination in SiMT.Therefore, we con…

2024

Paying More Attention to Source Context: Mitigating Unfaithful Translations from Large Language Model

ACL 2024findings

Large language models (LLMs) have showcased their remarkable capabilities to handle various downstream tasks, including multilingual machine translation ability. Despite their impressive performance, decoder-only LLMs lack an explicit alignment between source and target contexts, leading to translat…

2024

Question-guided Knowledge Graph Re-scoring and Injection for Knowledge Graph Question Answering

EMNLP 2024finding

Knowledge graph question answering (KGQA) involves answering natural language questions by leveraging structured information stored in a knowledge graph. Typically, KGQA initially retrieve a targeted subgraph from a large-scale knowledge graph, which serves as the basis for reasoning models to addre…

2024

Speech Sense Disambiguation: Tackling Homophone Ambiguity in End-to-End Speech Translation

ACL 2024long

End-to-end speech translation (ST) presents notable disambiguation challenges as it necessitates simultaneous cross-modal and cross-lingual transformations. While word sense disambiguation is an extensively investigated topic in textual machine translation, the exploration of disambiguation strategi…

2024

Unsupervised Sign Language Translation and Generation

ACL 2024findings

Motivated by the success of unsupervised neural machine translation (UNMT), we introduce an unsupervised sign language translation and generation network (USLNet), which learns from abundant single-modality (text and video) data without parallel sign language data. USLNet comprises two main componen…

2023

INFORM : Information eNtropy based multi-step reasoning FOR large language Models

EMNLP 2023long main

Large language models (LLMs) have demonstrated exceptional performance in reasoning tasks with dedicated Chain-of-Thought (CoT) prompts. Further enhancing CoT prompts with exquisite exemplars can significantly improve reasoning performance.However, the effectiveness of CoT prompts may fluctuate dram…

Cited by 0SourceScholar
2023

Improving Low-resource Question Answering by Augmenting Question Information

EMNLP 2023short findings

In the era of large models, low-resource question-answering tasks lag, emphasizing the importance of data augmentation - a key research avenue in natural language processing. The main challenges include leveraging the large model's internal knowledge for data augmentation, determining which QA data…

Cited by 0SourceScholar
2023

Improving Translation Quality Estimation with Bias Mitigation

ACL 2023long

State-of-the-art translation Quality Estimation (QE) models are proven to be biased. More specifically, they over-rely on monolingual features while ignoring the bilingual semantic alignment. In this work, we propose a novel method to mitigate the bias of the QE model and improve estimation performa…

Cited by 5SourcePDFScholar
2023

PromptST: Abstract Prompt Learning for End-to-End Speech Translation

EMNLP 2023long main

An end-to-end speech-to-text (S2T) translation model is usually initialized from a pre-trained speech recognition encoder and a pre-trained text-to-text (T2T) translation decoder. Although this straightforward setting has been shown empirically successful, there do not exist clear answers to the res…

Cited by 0SourcecodeScholar
2022

Document-Level Relation Extraction with Sentences Importance Estimation and Focusing

NAACL 2022long

Document-level relation extraction (DocRE) aims to determine the relation between two entities from a document of multiple sentences. Recent studies typically represent the entire document by sequence- or graph-based models to predict the relations of all entity pairs. However, we find that such a m…

2022

Effective Graph Context Representation for Document-level Machine Translation

IJCAI 2022poster

Document-level neural machine translation (DocNMT) universally encodes several local sentences or the entire document. Thus, DocNMT does not consider the relevance of document-level contextual information, for example, some context (i.e., content words, logical order, and co-occurrence relation) is…

Cited by 2SourcePDFScholar
2022

Synchronous Refinement for Neural Machine Translation

ACL 2022findings

Machine translation typically adopts an encoder-to-decoder framework, in which the decoder generates the target sentence word-by-word in an auto-regressive manner. However, the auto-regressive decoder faces a deep-rooted one-pass issue whereby each generated word is considered as one element of the…

Cited by 3SourcePDFScholar
2021

Self-Training for Unsupervised Neural Machine Translation in Unbalanced Training Data Scenarios

NAACL 2021long

Unsupervised neural machine translation (UNMT) that relies solely on massive monolingual corpora has achieved remarkable results in several translation tasks. However, in real-world scenarios, massive monolingual corpora do not exist for some extremely low-resource languages such as Estonian, and UN…

Cited by 12SourcePDFScholar
2020

Data-dependent Gaussian Prior Objective for Language Generation

ICLR 2020talk

For typical sequence prediction problems such as language generation, maximum likelihood estimation (MLE) has commonly been adopted as it encourages the predicted sequence most consistent with the ground-truth sequence to have the highest probability of occurring. However, MLE focuses on once-to-all…

Cited by 69SourceScholar
2020

Neural Machine Translation with Universal Visual Representation

ICLR 2020spotlight

Though visual information has been introduced for enhancing neural machine translation (NMT), its effectiveness strongly relies on the availability of large amounts of bilingual parallel sentence pairs with manual image annotations. In this paper, we present a universal visual representation learned…

Cited by 141SourcecodeScholar
2020

Robust Machine Reading Comprehension by Learning Soft labels

COLING 2020main

Neural models have achieved great success on the task of machine reading comprehension (MRC), which are typically trained on hard labels. We argue that hard labels limit the model capability on generalization due to the label sparseness problem. In this paper, we propose a robust training method for…

2020

Robust Unsupervised Neural Machine Translation with Adversarial Denoising Training

COLING 2020main

Unsupervised neural machine translation (UNMT) has recently attracted great interest in the machine translation community. The main advantage of the UNMT lies in its easy collection of required large training text sentences while with only a slightly worse performance than supervised neural machine…