Joint-Centric Dual Contrastive Alignment with Structure-Preserving and Information-Balanced Regularization
Summary
Researchers introduce HILBERT (HIerarchical Long-sequence Balanced Embedding with Reciprocal contrastive Training), a novel cross-attentive multimodal framework designed for learning document-level audio-text representations from long, segmented sequences, particularly in low-resource data environments. HILBERT utilizes frozen pre-trained speech and language encoders to extract segment-level features, which are then combined using cross-modal attention and self-attentive pooling to create modality-specific document representations and a unified cross-attentive embedding. To address severe audio-text dimensional imbalance and align modalities while maintaining individual modality structure, the framework employs a reciprocal dual contrastive objective that aligns audio-to-joint and text-to-joint representations. Additionally, HILBERT incorporates a Centered Kernel Alignment (CKA) loss for structural consistency and a mutual information balancing loss to prevent modality dominance. For downstream tasks, it uses a Mixture-of-Experts (MoE) classifier over concatenated representations, demonstrating superior performance in imbalanced multi-class settings.
Key takeaway
For research scientists developing multimodal models for long audio-text sequences, HILBERT offers a robust approach to learning balanced representations, especially in low-resource scenarios. You should consider implementing its reciprocal dual contrastive objective and auxiliary regularization techniques, such as CKA loss and mutual information balancing, to improve alignment and prevent modality dominance in your own models.
Key insights
HILBERT aligns audio-text representations using dual contrastive learning and regularization for long sequences in low-resource settings.
Principles
- Align to a joint embedding, not directly.
- Preserve modality structure with CKA loss.
- Balance information flow across modalities.
Method
HILBERT extracts segment features, aggregates them via cross-modal attention, and uses a reciprocal dual contrastive objective with CKA and mutual information balancing losses for alignment.
In practice
- Use frozen pre-trained encoders.
- Employ MoE for heterogeneous labels.
- Apply CKA for structural consistency.
Topics
- HILBERT Framework
- Multimodal Representation Learning
- Dual Contrastive Alignment
- Centered Kernel Alignment
- Information-Balanced Regularization
Best for: Research Scientist, AI Scientist, Machine Learning Engineer, NLP Engineer
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Editorial summary, takeaway, and curation by AIssential. Original article published by Artificial Intelligence.