Yik-Cheung Tam


2025

pdf bib
Predicate-Guided Generation for Mathematical Reasoning
Jiajun Chen | Yik-Cheung Tam
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing

We present Prolog-MATH, a curated corpus designed to support mathematical reasoning in large language models (LLMs) through logic programming. Each verbal math problem in the dataset is paired with a chain-of-thought explanation to generate Prolog program via a two-stage automated pipeline. In the first stage, an LLM (e.g., Deepseek-V3) predicts a set of relevant mathematical predicates that could be useful in solving the problem. In the second stage, the LLM uses these suggested predicates along with the expected answer type to gen- erate a complete Prolog program. To improve coverage, we fine-tune an open-source LLM us- ing supervised fine-tuning, followed by GRPO (Group Relative Policy Optimization) training to address problems that Deepseek-V3 fails to solve. To support this training, we propose a predicate-aware reward function that evaluates how well the generated solution incorporates the suggested predicates, complementing the standard binary reward. Experimental results show that: 1) Our two-stage pipeline achieves 81.3% solution coverage on the MATH training set; 2) GRPO training with the predicate-aware reward function enables a series of base models to correctly solve additional problems missed by Deepseek-V3, further increasing solution coverage to 97.4%. Data and source code can be obtained at the Github repository.

pdf bib
VLA-Mark: A cross modal watermark for large vision-language alignment models
Shuliang Liu | Zheng Qi | Jesse Jiaxi Xu | Yibo Yan | Junyan Zhang | He Geng | Aiwei Liu | Peijie Jiang | Jia Liu | Yik-Cheung Tam | Xuming Hu
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing

Vision-language models demand watermarking solutions that protect intellectual property without compromising multimodal coherence. Existing text watermarking methods disrupt visual-textual alignment through biased token selection and static strategies, leaving semantic-critical concepts vulnerable. We propose VLA-Mark, a vision-aligned framework that embeds detectable watermarks while preserving semantic fidelity through cross-modal coordination. Our approach integrates multiscale visual-textual alignment metrics, combining localized patch affinity, global semantic coherence, and contextual attention patterns, to guide watermark injection without model retraining. An entropy-sensitive mechanism dynamically balances watermark strength and semantic preservation, prioritizing visual grounding during low-uncertainty generation phases. Experiments show 7.4% lower PPL and 26.6% higher BLEU than conventional methods, with near-perfect detection (98.8% AUC). The framework demonstrates 96.1% attack resilience against attacks such as paraphrasing and synonym substitution, while maintaining text-visual consistency, establishing new standards for quality-preserving multimodal watermarking.

2024

pdf bib
Arithmetic Reasoning with LLM: Prolog Generation & Permutation
Xiaocheng Yang | Bingsen Chen | Yik-Cheung Tam
Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 2: Short Papers)

Instructing large language models (LLMs) to solve elementary school math problems has shown great success using Chain of Thought (CoT). However, the CoT approach relies on an LLM to generate a sequence of arithmetic calculations which can be prone to cascaded calculation errors. We hypothesize that an LLM should focus on extracting predicates and generating symbolic formulas from the math problem description so that the underlying calculation can be done via an external code interpreter. We investigate using LLM to generate Prolog programs to solve mathematical questions. Experimental results show that our Prolog-based arithmetic problem-solving outperforms CoT generation in the GSM8K benchmark across three distinct LLMs. In addition, given the insensitive ordering of predicates and symbolic formulas in Prolog, we propose to permute the ground truth predicates for more robust LLM training via data augmentation.

2019

pdf bib
Rhetorically Controlled Encoder-Decoder for Modern Chinese Poetry Generation
Zhiqiang Liu | Zuohui Fu | Jie Cao | Gerard de Melo | Yik-Cheung Tam | Cheng Niu | Jie Zhou
Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics

Rhetoric is a vital element in modern poetry, and plays an essential role in improving its aesthetics. However, to date, it has not been considered in research on automatic poetry generation. In this paper, we propose a rhetorically controlled encoder-decoder for modern Chinese poetry generation. Our model relies on a continuous latent variable as a rhetoric controller to capture various rhetorical patterns in an encoder, and then incorporates rhetoric-based mixtures while generating modern Chinese poetry. For metaphor and personification, an automated evaluation shows that our model outperforms state-of-the-art baselines by a substantial margin, while human evaluation shows that our model generates better poems than baseline methods in terms of fluency, coherence, meaningfulness, and rhetorical aesthetics.

2018

pdf bib
Read and Comprehend by Gated-Attention Reader with More Belief
Haohui Deng | Yik-Cheung Tam
Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Student Research Workshop

Gated-Attention (GA) Reader has been effective for reading comprehension. GA Reader makes two assumptions: (1) a uni-directional attention that uses an input query to gate token encodings of a document; (2) encoding at the cloze position of an input query is considered for answer prediction. In this paper, we propose Collaborative Gating (CG) and Self-Belief Aggregation (SBA) to address the above assumptions respectively. In CG, we first use an input document to gate token encodings of an input query so that the influence of irrelevant query tokens may be reduced. Then the filtered query is used to gate token encodings of an document in a collaborative fashion. In SBA, we conjecture that query tokens other than the cloze token may be informative for answer prediction. We apply self-attention to link the cloze token with other tokens in a query so that the importance of query tokens with respect to the cloze position are weighted. Then their evidences are weighted, propagated and aggregated for better reading comprehension. Experiments show that our approaches advance the state-of-theart results in CNN, Daily Mail, and Who Did What public test sets.

2015

pdf bib
Morphological Modeling for Machine Translation of English-Iraqi Arabic Spoken Dialogs
Katrin Kirchhoff | Yik-Cheung Tam | Colleen Richey | Wen Wang
Proceedings of the 2015 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

2007

pdf bib
Bilingual-LSA Based LM Adaptation for Spoken Language Translation
Yik-Cheung Tam | Ian Lane | Tanja Schultz
Proceedings of the 45th Annual Meeting of the Association of Computational Linguistics

2003

pdf bib
PLASER: Pronunciation Learning via Automatic Speech Recognition
Brian Mak | Manhung Siu | Mimi Ng | Yik-Cheung Tam | Yu-Chung Chan | Kin-Wah Chan | Ka-Yee Leung | Simon Ho | Jimmy Wong | Jacqueline Lo
Proceedings of the HLT-NAACL 03 Workshop on Building Educational Applications Using Natural Language Processing