Yujia Hu
Author directory2026
GPTKB 2.0: Browsing, Querying, and Auditing a Disambiguated LLM-Derived Knowledge Base
Yujia Hu | Tuan-Phong Nguyen | Simon Razniewski
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: System Demonstrations
Yujia Hu | Tuan-Phong Nguyen | Simon Razniewski
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: System Demonstrations
We present a web demo for exploring a large-scale disambiguated knowledge base materialized from a large language model (LLM). GPTKB 2.0 contains 38.4M triples over 1.6M canonical entities, together with 207.6K consolidated relations and 66K consolidated classes. Unlike prior LLM-derived knowledge bases that largely identify entities by surface strings, GPTKB 2.0 performs context-guided disambiguation during recursive KB construction, separating homonyms and merging synonymous mentions as facts are elicited. The demo makes this process inspectable: users can browse entities, follow links across the KB, and audit the provenance of individual facts, including surface forms, candidate matches, source triples, and disambiguation decisions. The interface further supports structured SPARQL queries, natural-language questions translated to SPARQL, and entity linking from user-provided text to canonical GPTKB 2.0 entries.
HateXScore: A Metric Suite for Evaluating Reasoning Quality in Hate Speech Explanations
Yujia Hu | Roy Ka-Wei Lee
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Yujia Hu | Roy Ka-Wei Lee
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Hateful speech detection is a key component of content moderation, yet current evaluation frameworks rarely assess why a text is deemed hateful. We introduce , a four-component metric suite designed to evaluate the reasoning quality of model explanations. It assesses (i) conclusion explicitness, (ii) faithfulness and causal grounding of quoted spans, (iii) protected group identification (policy-configurable), and (iv) logical consistency among these elements. Evaluated on six diverse hate speech datasets, reveals interpretability failures and annotation inconsistencies that are invisible to standard metrics like Accuracy or F1. Moreover, human evaluation shows strong agreement with , validating it as a practical tool for trustworthy and transparent moderation. Disclaimer: This paper contains sensitive content that may be disturbing to some readers.
Auditing a KB Elicitation of Frontier LLM Knowledge: A Multi-dimensional Analysis of GPTKB v1.5
Shrestha Ghosh | Luca Giordano | Yujia Hu | Tuan-Phong Nguyen | Simon Razniewski
Proceedings of the 11th Workshop on Automated Knowledge Base Construction (AKBC 2026)
Shrestha Ghosh | Luca Giordano | Yujia Hu | Tuan-Phong Nguyen | Simon Razniewski
Proceedings of the 11th Workshop on Automated Knowledge Base Construction (AKBC 2026)
LLMs are remarkable artifacts that have revolutionized a range of knowledge-intensive tasks. A significant contributor is their factual knowledge, which, to date, remains poorly understood, and is usually analyzed from biased samples. In this paper, we provide a framework and the results of a multi-dimensional analysis of GPTKB v1.5 (CITATION), a recursively elicited Knowledge Base (KB) of 100 million facts (or beliefs) of a frontier LLM, namely, GPT-4.1. Given the scale of the elicited facts, we provide a multi-dimensional approach to qualitatively and quantitatively analyze these facts as opposed to the mainstream fact completion benchmarks, which are prone to availability bias. We find that the models’ factual knowledge differs quite significantly from established knowledge bases, and that its accuracy is significantly lower than indicated by previous benchmarks. We also find that inconsistency, ambiguity and hallucinations are major issues, shedding light on future research opportunities in neuro-symbolic AI concerning extraction, consolidation and verification of factual LLM knowledge.
Epistemic Twins: Enabling a Symbolic Science of Language Model Knowledge
Simon Razniewski | Shrestha Ghosh | Luca Giordano | Yujia Hu | Josua Kowalzik | Tuan-Phong Nguyen
Proceedings of the 11th Workshop on Automated Knowledge Base Construction (AKBC 2026)
Simon Razniewski | Shrestha Ghosh | Luca Giordano | Yujia Hu | Josua Kowalzik | Tuan-Phong Nguyen
Proceedings of the 11th Workshop on Automated Knowledge Base Construction (AKBC 2026)
Large Language Models (LLMs) are impactful yet opaque artifacts. Subsymbolic by design, they are defined by billions of numeric weights that interact in a largely inscrutable manner. Current analysis paradigms are either black-box benchmarks that test model performance on pre-defined tasks, or mechanistic interpretability approaches that trace back outputs to specific weights. Both analysis methods are limited by the experimenter’s hypothesis space - one must know what to look for to find it. In this article, we argue for a third, radically different analysis paradigm: Epistemic Twins. We propose constructing large-scale symbolic approximations of LLMs in human-readable formats. This enables the comprehensive inspection of factual knowledge (or beliefs) inherent in the model without predefining hypotheses, facilitating large-scale auditing towards better understanding and explainability.
MMAC: A Multilingual, Multimodal Alignment Framework for Cultural Grounding Evaluation
Weihua Zheng | Zhengyuan Liu | Tanmoy Chakraborty | Weiwen Xu | Xiaoxue Gao | Bryan Chen Zhengyu Tan | Bowei Zou | Chang Liu | Yujia Hu | Xing Xie | Xiaoyuan Yi | Jing Yao | Chaojun Wang | Long Li | Rui Liu | Huiyao Liu | Koji Inoue | Ryuichi Sumida | Tatsuya Kawahara | Fan Xu | Lingyu Ye | Wei Tian | Dongjun Kim | Jimin Jung | Jaehyung Seo | Nadya Yuki Wangsajaya | Pham Minh Duc | Ojasva Saxena | Palash Nandi | Xiyan Tao | Wiwik Karlina | Tuan Luong | Keertana Arun Vasan | Roy Ka-Wei Lee | Nancy F. Chen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Weihua Zheng | Zhengyuan Liu | Tanmoy Chakraborty | Weiwen Xu | Xiaoxue Gao | Bryan Chen Zhengyu Tan | Bowei Zou | Chang Liu | Yujia Hu | Xing Xie | Xiaoyuan Yi | Jing Yao | Chaojun Wang | Long Li | Rui Liu | Huiyao Liu | Koji Inoue | Ryuichi Sumida | Tatsuya Kawahara | Fan Xu | Lingyu Ye | Wei Tian | Dongjun Kim | Jimin Jung | Jaehyung Seo | Nadya Yuki Wangsajaya | Pham Minh Duc | Ojasva Saxena | Palash Nandi | Xiyan Tao | Wiwik Karlina | Tuan Luong | Keertana Arun Vasan | Roy Ka-Wei Lee | Nancy F. Chen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
The global deployment of Large Language Models (LLMs) underscores the urgent need to evaluate their cultural alignment. However, assessing genuine “cultural awareness” across modalities (text, vision, speech) and languages remains a significant challenge. To comprehensively investigate this domain, we propose MMAC, a systematic framework that encompasses a tri-modally aligned cultural benchmark creation pipeline and a five-dimensional evaluation protocol to assess cross-country awareness disparities, evaluate cross-lingual and cross-modal consistency, and verify cultural knowledge generalization and grounding validity. Given the prevailing Western cultural bias in current models, we focus on 8 Asian countries as our dataset foundation to more acutely reveal potential cultural deficiencies in LLMs. Our dataset, MMAC-bench, features 27,000 human-curated questions across 10 languages. Crucially, it is the first dataset aligned at the input level across text, image, and speech, enabling direct cross-modal transfer tests. Each question consists of multiple-choice options accompanied by open-ended generated explanations, where 79% require multi-step reasoning grounded in cultural context, moving beyond simple memorization. We probe the causes of modal divergence, offering insights into fostering culturally robust MLLMs.
Constructing Disambiguated Knowledge Bases from Large Language Models at Scale
Yujia Hu | Tuan-Phong Nguyen | Simon Razniewski
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Yujia Hu | Tuan-Phong Nguyen | Simon Razniewski
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Automated Knowledge Base Construction (AKBC) is a core NLP task, and recent work proposes generating knowledge bases directly from large language models (LLMs), treating the model itself as the knowledge source. However, LLMs natively possess no representation of entities, leading to duplicate entries as well as conflations.
We propose DisamKB, a methodology for constructing disambiguated KBs directly from LLMs. DisamKB incorporates on-the-fly disambiguation of entities, relations and classes, and is meticulously designed to satisfy both scalability and disambiguation accuracy. We analyze the central design decisions and characterize the trade-offs between accuracy, scale, and cost. We execute DisamKB at scale, obtaining a materialized KB containing over 1M disambiguated entities and 38.4M triples. This represents the first million-scale LLM-native KB with explicit internal canonicalization of entities, relations, and classes, a significant departure from prior Wikimedia-centric works. DisamKB is anonymously available at https://gptkb.org/.
We propose DisamKB, a methodology for constructing disambiguated KBs directly from LLMs. DisamKB incorporates on-the-fly disambiguation of entities, relations and classes, and is meticulously designed to satisfy both scalability and disambiguation accuracy. We analyze the central design decisions and characterize the trade-offs between accuracy, scale, and cost. We execute DisamKB at scale, obtaining a materialized KB containing over 1M disambiguated entities and 38.4M triples. This represents the first million-scale LLM-native KB with explicit internal canonicalization of entities, relations, and classes, a significant departure from prior Wikimedia-centric works. DisamKB is anonymously available at https://gptkb.org/.
2025
Toxicity Red-Teaming: Benchmarking LLM Safety in Singapore’s Low-Resource Languages
Yujia Hu | Ming Shan Hee | Preslav Nakov | Roy Ka-Wei Lee
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Yujia Hu | Ming Shan Hee | Preslav Nakov | Roy Ka-Wei Lee
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
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 framework for benchmarking LLM safety in Singapore’s diverse linguistic context, including Singlish, Chinese, Malay, and Tamil. SGToxicGuard adopts a red-teaming approach to systematically probe LLM vulnerabilities in three real-world scenarios: conversation, question-answering, and content composition. We conduct extensive experiments with state-of-the-art multilingual LLMs, and the results uncover critical gaps in their safety guardrails. By offering actionable insights into cultural sensitivity and toxicity mitigation, we lay the foundation for safer and more inclusive AI systems in linguistically diverse environments. Disclaimer: This paper contains sensitive content that may be disturbing to some readers.
Enabling LLM Knowledge Analysis via Extensive Materialization
Yujia Hu | Tuan-Phong Nguyen | Shrestha Ghosh | Simon Razniewski
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Yujia Hu | Tuan-Phong Nguyen | Shrestha Ghosh | Simon Razniewski
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Large language models (LLMs) have majorly advanced NLP and AI, and next to their ability to perform a wide range of procedural tasks, a major success factor is their internalized factual knowledge. Since (Petroni et al., 2019), analyzing this knowledge has gained attention. However, most approaches investigate one question at a time via modest-sized pre-defined samples, introducing an “availability bias” (Tverski and Kahnemann, 1973) that prevents the analysis of knowledge (or beliefs) of LLMs beyond the experimenter’s predisposition.To address this challenge, we propose a novel methodology to comprehensively materialize an LLM’s factual knowledge through recursive querying and result consolidation. Our approach is a milestone for LLM research, for the first time providing constructive insights into the scope and structure of LLM knowledge (or beliefs).As a prototype, we extract a knowledge base (KB) comprising 101 million relational triples for over 2.9 million entities from GPT-4o-mini. We use GPTKB to exemplarily analyze GPT-4o-mini’s factual knowledge in terms of scale, accuracy, bias, cutoff and consistency, at the same time. Our resource is accessible at https://gptkb.org.
2024
ToxiCloakCN: Evaluating Robustness of Offensive Language Detection in Chinese with Cloaking Perturbations
Yunze Xiao | Yujia Hu | Kenny Tsu Wei Choo | Roy Ka-Wei Lee
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Yunze Xiao | Yujia Hu | Kenny Tsu Wei Choo | Roy Ka-Wei Lee
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
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 language particularly susceptible to such perturbations. We introduce ToxiCloakCN, an enhanced dataset derived from ToxiCN, augmented with homophonic substitutions and emoji transformations, to test the robustness of LLMs against these cloaking perturbations. Our findings reveal that existing models significantly underperform in detecting offensive content when these perturbations are applied. We provide an in-depth analysis of how different types of offensive content are affected by these perturbations and explore the alignment between human and model explanations of offensiveness. Our work highlights the urgent need for more advanced techniques in offensive language detection to combat the evolving tactics used to evade detection mechanisms.
2023
Who Wrote it and Why? Prompting Large-Language Models for Authorship Verification
Chia-Yu Hung | Zhiqiang Hu | Yujia Hu | Roy Lee
Findings of the Association for Computational Linguistics: EMNLP 2023
Chia-Yu Hung | Zhiqiang Hu | Yujia Hu | Roy Lee
Findings of the Association for Computational Linguistics: EMNLP 2023
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 approaches, face limitations in terms of data requirements and lack of explainability. To address these limitations, this paper proposes PromptAV, a novel technique that leverages Large-Language Models (LLMs) for AV by providing step-by-step stylometric explanation prompts. PromptAV outperforms state-of-the-art baselines, operates effectively with limited training data, and enhances interpretability through intuitive explanations, showcasing its potential as an effective and interpretable solution for the AV task.
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Co-authors
- Tuan-Phong Nguyen 5
- Simon Razniewski 5
- Roy Ka-Wei Lee 4
- Shrestha Ghosh 3
- Luca Giordano 2
- Tanmoy Chakraborty 1
- Nancy Chen 1
- Kenny Tsu Wei Choo 1
- Pham Minh Duc 1
- Xiaoxue Gao 1
- Ming Shan Hee 1
- Zhiqiang Hu 1
- Chia-Yu Hung 1
- Koji Inoue 1
- Jimin Jung 1
- Wiwik Karlina 1
- Tatsuya Kawahara 1
- Dongjun Kim 1
- Josua Kowalzik 1
- Roy Lee 1
- Long Li 1
- Chang Liu 1
- Huiyao Liu 1
- Rui Liu 1
- Zhengyuan Liu 1
- Tuan Luong 1
- Preslav Nakov 1
- Palash Nandi 1
- Ojasva Saxena 1
- Jaehyung Seo 1
- Ryuichi Sumida 1
- Bryan Chen Zhengyu Tan 1
- Xiyan Tao 1
- Wei Tian (田巍) 1
- Keertana Arun Vasan 1
- Chaojun Wang 1
- Nadya Yuki Wangsajaya 1
- Zheng Weihua 1
- Yunze Xiao 1
- Xing Xie 1
- Fan Xu (徐凡) 1
- Weiwen Xu 1
- Jing Yao 1
- Lingyu Ye 1
- Xiaoyuan Yi 1
- Bowei Zou (邹博伟) 1