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Cam-Tu Nguyen

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5 papers

1 author row

AAAI Conference 2026 Conference Paper

Learning to Compress: Unlocking the Potential of Large Language Models for Text Representation

Yeqin Zhang
Yizheng Zhao
Chen Hu
Binxing Jiao
Daxin Jiang
Ruihang Miao
Cam-Tu Nguyen

Text representation plays a critical role in tasks like clustering, retrieval, and other downstream applications. With the emergence of large language models (LLMs), there is increasing interest in harnessing their capabilities for this purpose. However, most of the LLMs are inherently causal and optimized for next-token prediction, making them suboptimal for producing holistic representations. To address this, recent studies introduced pretext tasks to adapt LLMs for text representation. Most of these tasks, however, rely on token-level prediction objectives, such as the masked next-token prediction (MNTP) used in LLM2Vec. In this work, we explore the untapped potential of context compression as a pretext task for unsupervised adaptation of LLMs. During compression pre-training, the model learns to generate compact memory tokens, which substitute the whole context for downstream sequence prediction. Experiments demonstrate that a well-designed compression objective can significantly enhance LLM-based text representations, outperforming models trained with token-level pretext tasks. Further improvements through contrastive learning produce a strong representation model (LLM2Comp) that outperforms contemporary LLM-based text encoders on a wide range of tasks while being more sample-efficient, requiring significantly less training data.

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AAAI Conference 2024 Conference Paper

Mitigating the Impact of False Negative in Dense Retrieval with Contrastive Confidence Regularization

Shiqi Wang
Yeqin Zhang
Cam-Tu Nguyen

In open-domain Question Answering (QA), dense text retrieval is crucial for finding relevant passages to generate answers. Typically, contrastive learning is used to train a retrieval model, which maps passages and queries to the same semantic space, making similar ones closer and dissimilar ones further apart. However, training such a system is challenging due to the false negative problem, where relevant passages may be missed during data annotation. Hard negative sampling, commonly used to improve contrastive learning, can introduce more noise in training. This is because hard negatives are those close to a given query, and thus more likely to be false negatives. To address this, we propose a novel contrastive confidence regularizer for Noise Contrastive Estimation (NCE) loss, a commonly used contrastive loss. Our analysis shows that the regularizer helps make the dense retrieval model more robust against false negatives with a theoretical guarantee. Additionally, we propose a model-agnostic method to filter out noisy negative passages in the dataset, improving any downstream dense retrieval models. Through experiments on three datasets, we demonstrate that our method achieves better retrieval performance in comparison to existing state-of-the-art dense retrieval systems.

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IJCAI Conference 2017 Conference Paper

AGRA: An Analysis-Generation-Ranking Framework for Automatic Abbreviation from Paper Titles

Jianbing Zhang
Yixin Sun
Shujian Huang
Cam-Tu Nguyen
Xiaoliang Wang
Xinyu Dai
Jiajun Chen
Yang Yu

People sometimes choose word-like abbreviations to refer to items with a long description. These abbreviations usually come from the descriptive text of the item and are easy to remember and pronounce, while preserving the key idea of the item. Coming up with a nice abbreviation is not an easy job, even for human. Previous assistant naming systems compose names by applying hand-written rules, which may not perform well. In this paper, we propose to view the naming task as an artificial intelligence problem and create a data set in the domain of academic naming. To generate more delicate names, we propose a three-step framework, including description analysis, candidate generation and abbreviation ranking, each of which is parameterized and optimizable. We conduct experiments to compare different settings of our framework with several analysis approaches from different perspectives. Compared to online or baseline systems, our framework could achieve the best results.

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AAAI Conference 2014 Conference Paper

Labeling Complicated Objects: Multi-View Multi-Instance Multi-Label Learning

Cam-Tu Nguyen
Xiaoliang Wang
Jing Liu
Zhi-Hua Zhou

Multi-Instance Multi-Label (MIML) is a learning framework where an example is associated with multiple labels and represented by a set of feature vectors (multiple instances). In the formalization of MIML learning, instances come from a single source (single view). To leverage multiple information sources (multi-view), we develop a multi-view MIML framework based on hierarchical Bayesian Network, and derive an effective learning algorithm based on variational inference. The model can naturally deal with examples in which some views could be absent (partial examples). On multi-view datasets, it is shown that our method is better than other multi-view and single-view approaches particularly in the presence of partial examples. On single-view benchmarks, extensive evaluation shows that our method is highly competitive or better than other MIML approaches on labeling examples and instances. Moreover, our method can effectively handle datasets with a large number of labels.

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IJCAI Conference 2013 Conference Paper

Multi-Modal Image Annotation with Multi-Instance Multi-Label LDA

Cam-Tu Nguyen
De-Chuan Zhan
Zhi-Hua Zhou

This paper studies the problem of image annotation in a multi-modal setting where both visual and textual information are available. We propose Multimodal Multi-instance Multi-label Latent Dirichlet Allocation (M3LDA), where the model consists of a visual-label part, a textual-label part and a labeltopic part. The basic idea is that the topic decided by the visual information and the topic decided by the textual information should be consistent, leading to the correct label assignment. Particularly, M3LDA is able to annotate image regions, thus provides a promising way to understand the relation between input patterns and output semantics. Experiments on Corel5K and ImageCLEF validate the effectiveness of the proposed method.

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