Zihao Li

May refer to several people

Other people with similar names: Zihao Li (Helsinki)


2025

pdf bib
Can Graph Neural Networks Learn Language with Extremely Weak Text Supervision?
Zihao Li | Lecheng Zheng | Bowen Jin | Dongqi Fu | Baoyu Jing | Yikun Ban | Jingrui He | Jiawei Han
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

While great success has been achieved in building vision models with Contrastive Language-Image Pre-training (CLIP) over Internet-scale image-text pairs, building transferable Graph Neural Networks (GNNs) with CLIP pipeline is challenging because of the scarcity of labeled data and text supervision, different levels of downstream tasks, and the conceptual gaps between domains. In this work, to address these issues, we propose a multi-modal prompt learning paradigm to effectively adapt pre-trained GNN to downstream tasks and data, given only a few semantically labeled samples, each with extremely weak text supervision. Our new paradigm embeds the graphs directly in the same space as the Large Language Models (LLMs) by learning both graph prompts and text prompts simultaneously. We demonstrate the superior performance of our paradigm in few-shot, multi-task-level, and cross-domain settings. Moreover, we build the first CLIP-style zero-shot classification prototype that can generalize GNNs to unseen classes with extremely weak text supervision.

pdf bib
Feature Extraction and Steering for Enhanced Chain-of-Thought Reasoning in Language Models
Zihao Li | Xu Wang | Yuzhe Yang | Ziyu Yao | Haoyi Xiong | Mengnan Du
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing

Large Language Models (LLMs) demonstrate the ability to solve reasoning and mathematical problems using the Chain-of-Thought (CoT) technique. Expanding CoT length, as seen in models such as DeepSeek-R1, significantly enhances this reasoning for complex problems, but requires costly and high-quality long CoT data and fine-tuning. This work, inspired by the deep thinking paradigm of DeepSeek-R1, utilizes a steering technique to enhance the reasoning ability of an LLM without external datasets. Our method first employs Sparse Autoencoders (SAEs) to extract interpretable features from vanilla CoT. These features are then used to steer the LLM’s internal states during generation. Recognizing that many LLMs do not have corresponding pre-trained SAEs, we further introduce a novel SAE-free steering algorithm, which directly computes steering directions from the residual activations of an LLM, obviating the need for an explicit SAE. Experimental results demonstrate that both our SAE-based and subsequent SAE-free steering algorithms significantly enhance the reasoning capabilities of LLMs.

pdf bib
Model Unlearning via Sparse Autoencoder Subspace Guided Projections
Xu Wang | Zihao Li | Benyou Wang | Yan Hu | Difan Zou
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing

Large language models (LLMs) store vast amounts of information, making them powerful yet raising privacy and safety concerns when selective knowledge removal is required. Existing unlearning strategies, ranging from gradient-based fine-tuning and model editing to sparse autoencoder (SAE) steering, either lack interpretability or fail to provide a robust defense against adversarial prompts. We propose **S**AE–Guided **S**ubspace **P**rojection **U**nlearning (**SSPU**), a novel framework that leverages SAE features to drive targeted updates in the model’s parameter space, enabling precise, interpretable, and robust unlearning. SSPU’s three-stage pipeline performs data-driven layer and feature selection, subspace construction via QR decomposition, and constrained optimization that controls activations into an “irrelevant” subspace while preserving retained knowledge. Overall, we use SAE features to construct a subspace that supervises unlearning, refining the loss and adding a regularization term to guide interpretable parameter updates. In experiments on the WMDP–Cyber forget set and three utility benchmarks (MMLU, TruthfulQA, GSM8K), SSPU reduces harmful knowledge accuracy by 3.22% compared to the strongest baseline. It also improves adversarial robustness, lowering malicious accuracy under jailbreak prompts compared to baselines. Our findings expose the limitations of prior unlearning methods and demonstrate how interpretable subspace-guided optimization can achieve robust, controllable model behavior.

pdf bib
Scaling Low-Resource MT via Synthetic Data Generation with LLMs
Ona de Gibert | Joseph Attieh | Teemu Vahtola | Mikko Aulamo | Zihao Li | Raúl Vázquez | Tiancheng Hu | Jörg Tiedemann
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing

We investigate the potential of LLM-generated synthetic data for improving low-resource Machine Translation (MT). Focusing on seven diverse target languages, we construct a document-level synthetic corpus from English Europarl, and extend it via pivoting to 147 additional language pairs. Automatic and human evaluation confirm its overall high quality. We study its practical application by (i) identifying effective training regimes, (ii) comparing our data with the HPLT dataset, (iii) studying the effect of varying training data size, and (iiii) testing its utility beyond English-centric MT. Finally, we introduce SynOPUS, a public repository for synthetic parallel datasets. Our findings show that LLM-generated synthetic data, even when noisy, can substantially improve MT performance for low-resource languages.

pdf bib
GlotEval: A Test Suite for Massively Multilingual Evaluation of Large Language Models
Hengyu Luo | Zihao Li | Joseph Attieh | Sawal Devkota | Ona de Gibert | Xu Huang | Shaoxiong Ji | Peiqin Lin | Bhavani Sai Praneeth Varma Mantina | Ananda Sreenidhi | Raúl Vázquez | Mengjie Wang | Samea Yusofi | Fei Yuan | Jörg Tiedemann
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing: System Demonstrations

Large language models (LLMs) are advancing at an unprecedented pace globally, with regions increasingly adopting these models for applications in their primary languages. Evaluating these models in diverse linguistic environments, especially in low-resource languages, has become a major challenge for academia and industry. Existing evaluation frameworks suffer from inconsistency across different benchmarks, being disproportionately focused on English and a handful of high-resource languages, thereby overlooking the realistic performance of LLMs in multilingual and lower-resource scenarios. To address this critical challenge of fragmented and inconsistent multilingual evaluation, we introduce GlotEval, a unified and lightweight framework that systematically integrates 27 benchmarks under a standardized ISO 639-3 language identifier system, allowing for seamless incorporation of new benchmarks. Supporting nine key tasks (machine translation, text classification, summarization, open-ended generation, reading comprehension, sequence labeling, intrinsic evaluation, instruction following and reasoning), spanning over dozens to hundreds of languages, GlotEval uniquely enables language-specific, cross-benchmark analysis and non-English-centric evaluations at a scale previously less practical for many researchers. This enables a precise diagnosis of model strengths and weaknesses in diverse linguistic contexts. A multilingual translation case study demonstrates GlotEval’s applicability for multilingual and language-specific evaluations.

pdf bib
Token-level Preference Self-Alignment Optimization for Multi-style Outline Controllable Generation
Zihao Li | Xuekong Xu | Ziyao Chen | Lixin Zou | Ethanhjwu Ethanhjwu | Qiang Chen | Chenliang Li
Findings of the Association for Computational Linguistics: ACL 2025

Multi-style outline controllable generation is crucial for multiple applications, including document semantic structuring and retrieval-augmented generation.The great success of preference alignment approaches encourages their application in controllable generation tasks.However, these attempts encounter several limitations: (1) response pair requirements, (2) substantial computation costs, and (3) insufficient exploitation of fine-grained preference signals.To address these problems, we propose a token-level preference self-alignment optimization, named TKPO, for outline controllable generation. TKPO extends the Bradley-Terry model from pair-wise to list-wise comparison, which is further applied at the token level for fine-grained preference signal utilization. In comparison to the representative methods, e.g., DPO, TKPO does not require response pairs; instead, we propose a controllable attributes-driven method to construct reject samples for self-alignment. Additionally, TKPO optimizes only the base model, thereby avoiding additional memory usage and substantial computational costs.We curate two outline controllable generation datasets with regard to language style and level-of-detail.Extensive experiments demonstrate that TKPO outperforms DPO by up to 19.28% in performance while requiring only 56.25% in training time.We release the code and datasets resources at https://github.com/WHUIR/TKPO.

pdf bib
Efficient On-Device Text Simplification for Firefox with Synthetic Data Fine-Tuning
Pablo Romero | Zihao Li | Matthew Shardlow
Proceedings of the Fourth Workshop on Text Simplification, Accessibility and Readability (TSAR 2025)

This work presents a system for on-device text simplification that enables users to process sensitive text without relying on cloud-based services. Through the use of quantization techniques and a novel approach to controllable text simplification we reduce model size by up to 75 percent with minimal performance degradation. Our models demonstrate efficient state-of-the-art results using a synthetic dataset of 2909 examples outperforming prior work trained on 300K examples. This efficiency stems from (1) a single control token strategy that precisely targets specific reading levels (2) a contrastive training approach that enriches model understanding through exposure to multiple simplification levels and (3) individual models that dedicate full parameter capacity to specific reading level transformations. Our best models achieve up to 82.18 BLEU at the Advanced level and 46.12 SARI at the Elementary level on standard benchmarks with performance preserved even after aggressive quantization. This work is implemented as a collaboration with the Mozilla AI team to process text entirely locally ensuring sensitive information never leaves the users device. We have a demonstration video https//youtu.be/TzmaxnARMzg and a web demo available at https//pablorom2004.github.io/Simplification-Web-Demo

2024

pdf bib
Efficient Sparse Attention needs Adaptive Token Release
Chaoran Zhang | Lixin Zou | Dan Luo | Xiangyang Luo | Zihao Li | Min Tang | Chenliang Li
Findings of the Association for Computational Linguistics: ACL 2024

2023

pdf bib
Comparing Generic and Expert Models for Genre-Specific Text Simplification
Zihao Li | Matthew Shardlow | Fernando Alva-Manchego
Proceedings of the Second Workshop on Text Simplification, Accessibility and Readability

We investigate how text genre influences the performance of models for controlled text simplification. Regarding datasets from Wikipedia and PubMed as two different genres, we compare the performance of genre-specific models trained by transfer learning and prompt-only GPT-like large language models. Our experiments showed that: (1) the performance loss of genre-specific models on general tasks can be limited to 2%, (2) transfer learning can improve performance on genre-specific datasets up to 10% in SARI score from the base model without transfer learning, (3) simplifications generated by the smaller but more customized models show similar performance in simplicity and a better meaning reservation capability to the larger generic models in both automatic and human evaluations.

2022

pdf bib
An Investigation into the Effect of Control Tokens on Text Simplification
Zihao Li | Matthew Shardlow | Saeed Hassan
Proceedings of the Workshop on Text Simplification, Accessibility, and Readability (TSAR-2022)

Recent work on text simplification has focused on the use of control tokens to further the state of the art. However, it is not easy to further improve without an in-depth comprehension of the mechanisms underlying control tokens. One unexplored factor is the tokenisation strategy, which we also explore. In this paper, we (1) reimplemented ACCESS, (2) explored the effects of varying control tokens, (3) tested the influences of different tokenisation strategies, and (4) demonstrated how separate control tokens affect performance. We show variations of performance in the four control tokens separately. We also uncover how the design of control tokens could influence the performance and propose some suggestions for designing control tokens, which also reaches into other controllable text generation tasks.