Thong Nguyen
Author directoryAlso published as: Thong Thanh Nguyen
Other people with similar names: Thong Nguyen
Unverified author pages with similar names: Thong Nguyen
2026
When In-Distribution Gains Fail: Evaluating Weak-to-Strong Reward Models under Preference Shift
Khoi M. Le | Tri Cao | Phong Nam Huu Nguyen | Cong-Duy T Nguyen | Anh Tuan Luu | Chunyan Miao | See-Kiong Ng | Thong Thanh Nguyen
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Khoi M. Le | Tri Cao | Phong Nam Huu Nguyen | Cong-Duy T Nguyen | Anh Tuan Luu | Chunyan Miao | See-Kiong Ng | Thong Thanh Nguyen
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Weak-to-strong (W2S) generalization is a promising framework for scalable oversight, yet existing evaluations often test students under matched train-test distributions. Therefore, we study W2S preference learning under zero-shot distribution shift and find that strong students trained on weak preference labels can appear successful in-distribution while failing to transfer across preference datasets. We provide evidence consistent with a representational failure mode in which weak-supervised fine-tuning may move the strong model toward source-domain features instead of maintaining broadly transferable preference representations. To mitigate this, we propose *Representation Anchoring* (Anchor), a simple yet effective regularizer that constrains excessive drift from the pretrained strong model’s representation space during fine-tuning, while still allowing task-relevant adaptation. Across preference domains, datasets, and model families, Anchor improves out-of-distribution transfer while maintaining competitive in-distribution performance. Together, our evaluation protocol, transfer-aware metrics, and method expose hidden brittleness in current W2S reward modeling and provide a practical path toward more robust preference transfer.
Don’t Read Everything: A Curvature-Conditioned Query for Linear Attention
Dong Le | Thong Thanh Nguyen | Cong-Duy T Nguyen | Anh Tuan Luu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Dong Le | Thong Thanh Nguyen | Cong-Duy T Nguyen | Anh Tuan Luu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Linear attention reduces the quadratic cost of softmax attention by maintaining a recurrent fast-weight state, but it consistently lags on in-context retrieval and long-context tasks. Existing remedies act on the write side of memory through gating, delta updates, or kernel feature maps, but the read step is left unchanged: every past key contributes additively to the output, so useful targets are diluted by the bulk of stored vectors. We borrow one specific piece of softmax’s geometry to construct a cheap read-time contraction of the query. A second-order Taylor expansion of the softmax log-partition at the isotropic-attention point gives a local quadratic model whose curvature coincides with the running key covariance, a quantity that can be maintained with the same recurrent/chunkwise mechanism as the linear-attention state. The associated linear operator contracts the query along the high-variance directions of memory before it reads the state. We call this mechanism Curvature-Conditioned Query (CCQ). CCQ modifies only the read step and is composable with any linear-attention backbone. Attached to GLA and Gated DeltaNet, it improves perplexity, zero-shot downstream accuracy, S-NIAH retrieval at and beyond the training context, length-extrapolation perplexity from 4K to 20K, and LongBench accuracy.
2025
Enhancing Multimodal Entity Linking with Jaccard Distance-based Conditional Contrastive Learning and Contextual Visual Augmentation
Cong-Duy T Nguyen | Xiaobao Wu | Thong Thanh Nguyen | Shuai Zhao | Khoi M. Le | Nguyen Viet Anh | Feng Yichao | Anh Tuan Luu
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Cong-Duy T Nguyen | Xiaobao Wu | Thong Thanh Nguyen | Shuai Zhao | Khoi M. Le | Nguyen Viet Anh | Feng Yichao | Anh Tuan Luu
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Previous research on multimodal entity linking (MEL) has primarily employed contrastive learning as the primary objective. However, using the rest of the batch as negative samples without careful consideration, these studies risk leveraging easy features and potentially overlook essential details that make entities unique. In this work, we propose JD-CCL (Jaccard Distance-based Conditional Contrastive Learning), a novel approach designed to enhance the ability to match multimodal entity linking models. JD-CCL leverages meta-information to select negative samples with similar attributes, making the linking task more challenging and robust. Additionally, to address the limitations caused by the variations within the visual modality among mentions and entities, we introduce a novel method, CVaCPT (Contextual Visual-aid Controllable Patch Transform). It enhances visual representations by incorporating multi-view synthetic images and contextual textual representations to scale and shift patch representations. Experimental results on benchmark MEL datasets demonstrate the strong effectiveness of our approach.
2024
Topic-Aware Causal Intervention for Counterfactual Detection
Thong Thanh Nguyen | Truc-My Nguyen
Proceedings of the 4th International Conference on Natural Language Processing for Digital Humanities
Thong Thanh Nguyen | Truc-My Nguyen
Proceedings of the 4th International Conference on Natural Language Processing for Digital Humanities
Counterfactual statements, which describe events that did not or cannot take place, are beneficial to numerous NLP applications. Hence, we consider the problem of counterfactual detection (CFD) and seek to enhance the CFD models. Previous models are reliant on clue phrases to predict counterfactuality, so they suffer from significant performance drop when clue phrase hints do not exist during testing. Moreover, these models tend to predict non-counterfactuals over counterfactuals. To address these issues, we propose to integrate neural topic model into the CFD model to capture the global semantics of the input statement. We continue to causally intervene the hidden representations of the CFD model to balance the effect of the class labels. Extensive experiments show that our approach outperforms previous state-of-the-art CFD and bias-resolving methods in both the CFD and other bias-sensitive tasks.
Encoding and Controlling Global Semantics for Long-form Video Question Answering
Thong Thanh Nguyen | Zhiyuan Hu | Xiaobao Wu | Cong-Duy T Nguyen | See-Kiong Ng | Anh Tuan Luu
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Thong Thanh Nguyen | Zhiyuan Hu | Xiaobao Wu | Cong-Duy T Nguyen | See-Kiong Ng | Anh Tuan Luu
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Seeking answers effectively for long videos is essential to build video question answering (videoQA) systems. Previous methods adaptively select frames and regions from long videos to save computations. However, this fails to reason over the whole sequence of video, leading to sub-optimal performance. To address this problem, we introduce a state space layer (SSL) into multi-modal Transformer to efficiently integrate global semantics of the video, which mitigates the video information loss caused by frame and region selection modules. Our SSL includes a gating unit to enable controllability over the flow of global semantics into visual representations. To further enhance the controllability, we introduce a cross-modal compositional congruence objective to encourage global semantics aligned with the question. To rigorously evaluate long-form videoQA capacity, we construct two new benchmarks Ego-QA and MAD-QA featuring videos of considerably long length, i.e. 17.5 minutes and 1.9 hours, respectively. Extensive experiments demonstrate the superiority of our framework on these new as well as existing datasets.
2023
Gradient-Boosted Decision Tree for Listwise Context Model in Multimodal Review Helpfulness Prediction
Thong Nguyen | Xiaobao Wu | Xinshuai Dong | Cong-Duy Nguyen | Zhen Hai | Lidong Bing | Anh Tuan Luu
Findings of the Association for Computational Linguistics: ACL 2023
Thong Nguyen | Xiaobao Wu | Xinshuai Dong | Cong-Duy Nguyen | Zhen Hai | Lidong Bing | Anh Tuan Luu
Findings of the Association for Computational Linguistics: ACL 2023
Multimodal Review Helpfulness Prediction (MRHP) aims to rank product reviews based on predicted helpfulness scores and has been widely applied in e-commerce via presenting customers with useful reviews. Previous studies commonly employ fully-connected neural networks (FCNNs) as the final score predictor and pairwise loss as the training objective. However, FCNNs have been shown to perform inefficient splitting for review features, making the model difficult to clearly differentiate helpful from unhelpful reviews. Furthermore, pairwise objective, which works on review pairs, may not completely capture the MRHP goal to produce the ranking for the entire review list, and possibly induces low generalization during testing. To address these issues, we propose a listwise attention network that clearly captures the MRHP ranking context and a listwise optimization objective that enhances model generalization. We further propose gradient-boosted decision tree as the score predictor to efficaciously partition product reviews’ representations. Extensive experiments demonstrate that our method achieves state-of-the-art results and polished generalization performance on two large-scale MRHP benchmark datasets.