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Roy Ka-Wei Lee

33 accepted papers

2026

AdaMCoT: Rethinking Cross-Lingual Factual Reasoning Through Adaptive Multilingual Chain-of-Thought

AAAI 2026technical

Large language models (LLMs) have shown impressive multilingual capabilities through pretraining on diverse corpora. While these models show strong reasoning abilities, their performance varies significantly across languages due to imbalanced training data distribution. Existing approaches using sam

Cited by 11SourcePDFScholar
2026

Beyond I’m Sorry, I Can’t: Dissecting Large-Language-Model Refusal

AAAI 2026technical

Refusal on harmful prompts is a key safety behaviour in instruction‑tuned large language models (LLMs), yet the internal causes of this behaviour remain poorly understood. We study two public instruction tuned models—Gemma‑2-2B‑IT and LLaMA‑3.1-8B‑IT using sparse autoencoders (SAEs) trained on resid

Cited by 0SourcePDFScholar
2026

LongWriter-Zero: Mastering Ultra-Long Text Generation via Reinforcement Learning

ICLR 2026oral

Ultra-long generation by large language models (LLMs) is a widely demanded scenario, yet it remains a significant challenge due to their maximum generation length limit and overall quality degradation as sequence length increases. Previous approaches, exemplified by LongWriter, typically rely on ''t…

Cited by 0SourceScholar
2026

Multi-Agent VLMs Guided Self-Training with PNU Loss for Low-Resource Offensive Content Detection

AAAI 2026technical

Accurate detection of offensive content on social media demands high-quality labeled data; however, such data is often scarce due to the low prevalence of offensive instances and the high cost of manual annotation. To address this low-resource challenge, we propose a self-training framework that lev

Cited by 0SourcePDFScholar
2026

SafeLens: Segment-Level Hate Speech Detection in Online Videos

AAAI 2026technical

We present SafeLens, a lightweight segment-level video moderation system that fuses speech, text, and visual frames to produce hateful content detection for each segment. For every segment, SafeLens returns a structured prediction: label, prediction confidence, reasons for flag, harm categories. The

Cited by 0SourcePDFScholar
2025

CCL-XCoT: An Efficient Cross-Lingual Knowledge Transfer Method for Mitigating Hallucination Generation

EMNLP 2025

Multilingual Large Language Models (MLLMs) demonstrate strong generalization across languages, yet they remain prone to hallucinations, especially in low-resource languages, due to training data imbalances. These hallucinations, which include inaccurate or fabricated outputs, are particularly proble

Cited by 0SourcePDFScholar
2025

Finding the Sweet Spot: Preference Data Construction for Scaling Preference Optimization

ACL 2025long

Iterative data generation and model retraining are widely used to align large language models (LLMs).It typically involves a policy model to generate on-policy responses and a reward model to guide training data selection. Direct Preference Optimization (DPO) further enhances this process by constru…

Cited by 0SourcePDFScholar
2025

Humor in Pixels: Benchmarking Large Multimodal Models Understanding of Online Comics

EMNLP 2025

Understanding humor is a core aspect of social intelligence, yet it remains a significant challenge for Large Multimodal Models (LMMs). We introduce PixelHumor, a benchmark dataset of 2,800 annotated multi-panel comics designed to evaluate LMMs’ ability to interpret multimodal humor and recognize na

Cited by 0SourcePDFScholar
2025

Is LLM an Overconfident Judge? Unveiling the Capabilities of LLMs in Detecting Offensive Language with Annotation Disagreement

ACL 2025finding

Large Language Models (LLMs) have become essential for offensive language detection, yet their ability to handle annotation disagreement remains underexplored. Disagreement samples, which arise from subjective interpretations, pose a unique challenge due to their ambiguous nature. Understanding how…

2025

LongGenBench: Benchmarking Long-Form Generation in Long Context LLMs

ICLR 2025poster

Current benchmarks like ``$\textit{Needle-in-a-Haystack}$'' ($\textit{NIAH}$), $\textit{Ruler}$, and $\textit{Needlebench}$ focus on models' ability to understand long-context input sequences but fail to capture a critical dimension: the generation of high-quality long-form text. Applications such a…

Cited by 6SourcePDFScholar
2025

Persuasion Dynamics in LLMs: Investigating Robustness and Adaptability in Knowledge and Safety with DuET-PD

EMNLP 2025

Large Language Models (LLMs) can struggle to balance gullibility to misinformation and resistance to valid corrections in persuasive dialogues, a critical challenge for reliable deployment. We introduce **DuET-PD** (**Du**al **E**valuation for **T**rust in **P**ersuasive **D**ialogues), a framework

2025

Resolving Conflicting Evidence in Automated Fact-Checking: A Study on Retrieval-Augmented LLMs

IJCAI 2025

Large Language Models (LLMs) augmented with retrieval mechanisms have demonstrated significant potential in fact-checking tasks by integrating external knowledge. However, their reliability decreases when confronted with conflicting evidence from sources of varying credibility. This paper presents t

2025

Toxicity Red-Teaming: Benchmarking LLM Safety in Singapore’s Low-Resource Languages

EMNLP 2025

The advancement of Large Language Models (LLMs) has transformed natural language processing; however, their safety mechanisms remain under-explored in low-resource, multilingual settings. Here, we aim to bridge this gap. In particular, we introduce SGToxicGuard, a novel dataset and evaluation framew

Cited by 0SourcePDFScholar
2025

Understanding Refusal in Language Models with Sparse Autoencoders

EMNLP 2025

Refusal is a key safety behavior in aligned language models, yet the internal mechanisms driving refusals remain opaque. In this work, we conduct a mechanistic study of refusal in instruction-tuned LLMs using sparse autoencoders to identify latent features that causally mediate refusal behaviors. We

2025

Unmasking Implicit Bias: Evaluating Persona-Prompted LLM Responses in Power-Disparate Social Scenarios

NAACL 2025long

Large language models (LLMs) have demonstrated remarkable capabilities in simulating human behaviour and social intelligence. However, they risk perpetuating societal biases, especially when demographic information is involved. We introduce a novel framework using cosine distance to measure semantic…

Cited by 0SourcePDFScholar
2024

Bridging Modalities: Enhancing Cross-Modality Hate Speech Detection with Few-Shot In-Context Learning

EMNLP 2024main

The widespread presence of hate speech on the internet, including formats such as text-based tweets and multimodal memes, poses a significant challenge to digital platform safety. Recent research has developed detection models tailored to specific modalities; however, there is a notable gap in trans…

Cited by 2SourcePDFScholar
2024

Math-LLaVA: Bootstrapping Mathematical Reasoning for Multimodal Large Language Models

EMNLP 2024finding

Large language models (LLMs) have demonstrated impressive reasoning capabilities, particularly in textual mathematical problem-solving. However, existing open-source image instruction fine-tuning datasets, containing limited question-answer pairs per image, do not fully exploit visual information to…

2024

Recent Advances in Online Hate Speech Moderation: Multimodality and the Role of Large Models

EMNLP 2024finding

Moderating hate speech (HS) in the evolving online landscape is a complex challenge, compounded by the multimodal nature of digital content. This survey examines recent advancements in HS moderation, focusing on the burgeoning role of large language models (LLMs) and large multimodal models (LMMs) i…

Cited by 1SourcePDFScholar
2024

ToxiCloakCN: Evaluating Robustness of Offensive Language Detection in Chinese with Cloaking Perturbations

EMNLP 2024main

Detecting hate speech and offensive language is essential for maintaining a safe and respectful digital environment. This study examines the limitations of state-of-the-art large language models (LLMs) in identifying offensive content within systematically perturbed data, with a focus on Chinese, a…

2023

Adapter-TST: A Parameter Efficient Method for Multiple-Attribute Text Style Transfer

EMNLP 2023long findings

Adapting a large language model for multiple-attribute text style transfer via fine-tuning can be challenging due to the substantial amount of computational resources and labeled data required for the specific downstream task. In this paper, we address this challenge by introducing \textsf{Adapter-T…

Cited by 0SourceScholar
2023

Decoding the Underlying Meaning of Multimodal Hateful Memes

IJCAI 2023poster

Recent studies have proposed models that yielded promising performance for the hateful meme classification task. Nevertheless, these proposed models do not generate interpretable explanations that uncover the underlying meaning and support the classification output. A major reason for the lack of ex…

2023

Evaluating GPT-3 Generated Explanations for Hateful Content Moderation

IJCAI 2023poster

Recent research has focused on using large language models (LLMs) to generate explanations for hate speech through fine-tuning or prompting. Despite the growing interest in this area, these generated explanations' effectiveness and potential limitations remain poorly understood. A key concern is tha…

2023

Improving the Detection of Multilingual Online Attacks with Rich Social Media Data from Singapore

ACL 2023long

Toxic content is a global problem, but most resources for detecting toxic content are in English. When datasets are created in other languages, they often focus exclusively on one language or dialect. In many cultural and geographical settings, however, it is common to code-mix languages, combining…

2023

LLM-Adapters: An Adapter Family for Parameter-Efficient Fine-Tuning of Large Language Models

EMNLP 2023long main

The success of large language models (LLMs), like GPT-4 and ChatGPT, has led to the development of numerous cost-effective and accessible alternatives that are created by finetuning open-access LLMs with task-specific data (e.g., ChatDoctor) or instruction data (e.g., Alpaca). Among the various fine…

Cited by 0SourcecodeScholar
2023

Language Guided Visual Question Answering: Elevate Your Multimodal Language Model Using Knowledge-Enriched Prompts

EMNLP 2023short findings

Visual question answering (VQA) is the task of answering questions about an image. The task assumes an understanding of both the image and the question to provide a natural language answer. VQA has gained popularity in recent years due to its potential applications in a wide range of fields, includi…

Cited by 0SourcecodeScholar
2023

Plan-and-Solve Prompting: Improving Zero-Shot Chain-of-Thought Reasoning by Large Language Models

ACL 2023long

Large language models (LLMs) have recently been shown to deliver impressive performance in various NLP tasks. To tackle multi-step reasoning tasks, Few-shot chain-of-thought (CoT) prompting includes a few manually crafted step-by-step reasoning demonstrations which enable LLMs to explicitly generate…

2023

Who Wrote it and Why? Prompting Large-Language Models for Authorship Verification

EMNLP 2023short findings

Authorship verification (AV) is a fundamental task in natural language processing (NLP) and computational linguistics, with applications in forensic analysis, plagiarism detection, and identification of deceptive content. Existing AV techniques, including traditional stylometric and deep learning ap…

Cited by 0SourceScholar
2021

On Orthogonality Constraints for Transformers

ACL 2021short

Orthogonality constraints encourage matrices to be orthogonal for numerical stability. These plug-and-play constraints, which can be conveniently incorporated into model training, have been studied for popular architectures in natural language processing, such as convolutional neural networks and re…

Cited by 24SourcePDFScholar
2020

Teacher-Student Networks with Multiple Decoders for Solving Math Word Problem

IJCAI 2020poster

Math word problem (MWP) is challenging due to the limitation in training data where only one “standard” solution is available. MWP models often simply fit this solution rather than truly understand or solve the problem. The generalization of models (to diverse word scenarios) is thus limited. To add…