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Main Authors: Ihsan, Md. Tawfique, Rafi, Md. Rakibul Hasan, Raihan, Ahmed Shoyeb, Ahmed, Imtiaz, Azeem, Abdullahil
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2511.16571
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author Ihsan, Md. Tawfique
Rafi, Md. Rakibul Hasan
Raihan, Ahmed Shoyeb
Ahmed, Imtiaz
Azeem, Abdullahil
author_facet Ihsan, Md. Tawfique
Rafi, Md. Rakibul Hasan
Raihan, Ahmed Shoyeb
Ahmed, Imtiaz
Azeem, Abdullahil
contents Severe class imbalance is common in real-world tabular learning, where rare but important minority classes are essential for reliable prediction. Existing generative oversampling methods such as GANs, VAEs, and diffusion models can improve minority-class performance, but they often struggle with tabular heterogeneity, training stability, and privacy concerns. We propose a family of latent-space, tree-driven diffusion methods for minority oversampling that use conditional flow matching with gradient-boosted trees as the vector-field learner. The models operate in compact latent spaces to preserve tabular structure and reduce computation. We introduce three variants: PCAForest, which uses linear PCA embedding; EmbedForest, which uses a learned nonlinear embedding; and AttentionForest, which uses an attention-augmented embedding. Each method couples a GBT-based flow with a decoder back to the original feature space. Across 11 datasets from healthcare, finance, and manufacturing, AttentionForest achieves the best average minority recall while maintaining competitive precision, calibration, and distributional similarity. PCAForest and EmbedForest reach similar utility with much faster generation, offering favorable accuracy-efficiency trade-offs. Privacy evaluated with nearest-neighbor distance ratio and distance-to-closest-record is comparable to or better than the ForestDiffusion baseline. Ablation studies show that smaller embeddings tend to improve minority recall, while aggressive learning rates harm stability. Overall, latent-space, tree-driven diffusion provides an efficient and privacy-aware approach to high-fidelity tabular data augmentation under severe class imbalance.
format Preprint
id arxiv_https___arxiv_org_abs_2511_16571
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Boosting Predictive Performance on Tabular Data through Data Augmentation with Latent-Space Flow-Based Diffusion
Ihsan, Md. Tawfique
Rafi, Md. Rakibul Hasan
Raihan, Ahmed Shoyeb
Ahmed, Imtiaz
Azeem, Abdullahil
Machine Learning
Severe class imbalance is common in real-world tabular learning, where rare but important minority classes are essential for reliable prediction. Existing generative oversampling methods such as GANs, VAEs, and diffusion models can improve minority-class performance, but they often struggle with tabular heterogeneity, training stability, and privacy concerns. We propose a family of latent-space, tree-driven diffusion methods for minority oversampling that use conditional flow matching with gradient-boosted trees as the vector-field learner. The models operate in compact latent spaces to preserve tabular structure and reduce computation. We introduce three variants: PCAForest, which uses linear PCA embedding; EmbedForest, which uses a learned nonlinear embedding; and AttentionForest, which uses an attention-augmented embedding. Each method couples a GBT-based flow with a decoder back to the original feature space. Across 11 datasets from healthcare, finance, and manufacturing, AttentionForest achieves the best average minority recall while maintaining competitive precision, calibration, and distributional similarity. PCAForest and EmbedForest reach similar utility with much faster generation, offering favorable accuracy-efficiency trade-offs. Privacy evaluated with nearest-neighbor distance ratio and distance-to-closest-record is comparable to or better than the ForestDiffusion baseline. Ablation studies show that smaller embeddings tend to improve minority recall, while aggressive learning rates harm stability. Overall, latent-space, tree-driven diffusion provides an efficient and privacy-aware approach to high-fidelity tabular data augmentation under severe class imbalance.
title Boosting Predictive Performance on Tabular Data through Data Augmentation with Latent-Space Flow-Based Diffusion
topic Machine Learning
url https://arxiv.org/abs/2511.16571