Continual Learning for Speech Event Detection: Overcoming Catastrophic Forgetting and Disentangling Semantic and Acoustic Events

Core Concepts

A novel method called "Double Mixture" that combines a mixture of speech experts and a mixture of memory to effectively mitigate catastrophic forgetting and enhance the model's ability to generalize across different types of speech events.

Abstract

The paper introduces a new task called "Continual Event Detection from Speech" (CEDS), which aims to sequentially learn and recognize new speech event types while retaining previously learned knowledge. This task presents two key challenges: catastrophic forgetting and the disentanglement of semantic and acoustic events.
To address these challenges, the authors propose a novel method called "Double Mixture". This approach combines:

A mixture of speech experts, where each expert focuses on a specific task and the overall model dynamically adjusts the weights of each expert to maintain past knowledge during the learning process.

A mixture of memory, where the model stores mixed speech samples containing both semantic and acoustic events, and uses these samples during training to strengthen the collaboration between different speech experts and improve the model's generalization ability.

The authors conduct extensive experiments on three benchmark datasets (Speech-ACE05, Speech-MAVEN, and ESC-50) and two combined datasets (Speech Splicing and Speech Overlaying) to evaluate the performance of the proposed method. The results show that the Double Mixture approach outperforms various continual learning baselines in terms of average accuracy and forgetting rate, demonstrating its effectiveness in overcoming catastrophic forgetting and managing complex real-world speech scenarios with varying event combinations.

Stats

The average duration of audio files in the Speech Splicing dataset is 9.18 seconds for semantic events and 6.16 seconds for sound events.
The average duration of audio files in the Speech Overlaying dataset is 19.86 seconds for semantic events and 13.34 seconds for sound events.

Quotes

"The continual speech event detection task aims to sequentially learn and recognize new tasks from a speech stream."
"We introduce a novel strategy called Double Mixture. This approach combines a mixture of experts with automatically assigning a dedicated expert to each task for accruing new knowledge, and a mixture of memory, which is a simple yet effective method for replaying speech experiences."

Key Insights Distilled From

Double Mixture: Towards Continual Event Detection from Speech

by Jingqi Kang,... at arxiv.org 04-23-2024

https://arxiv.org/pdf/2404.13289.pdf

Deeper Inquiries

How can the proposed Double Mixture method be extended to handle more complex speech scenarios, such as multilingual or multi-speaker environments

The proposed Double Mixture method can be extended to handle more complex speech scenarios by incorporating techniques that address multilingual or multi-speaker environments. For multilingual scenarios, the model can be trained on diverse datasets containing multiple languages, allowing it to learn and distinguish between different languages during the continual learning process. This can involve incorporating language-specific experts within the mixture of experts framework to handle language-specific nuances and variations in speech patterns. Additionally, leveraging pre-trained multilingual models or incorporating language embeddings can enhance the model's ability to generalize across different languages.
In the case of multi-speaker environments, the model can be adapted to recognize and differentiate between different speakers by incorporating speaker-specific features or embeddings. By training the model on datasets with diverse speakers, it can learn to identify speaker characteristics and adapt its predictions accordingly. Techniques such as speaker diarization can be integrated to segment speech signals based on speaker identities, enabling the model to focus on individual speakers during training and inference. Furthermore, incorporating speaker embeddings or speaker-specific adaptation mechanisms can improve the model's performance in multi-speaker scenarios.
By extending the Double Mixture method to handle multilingual and multi-speaker environments, the model can enhance its robustness and adaptability in complex speech scenarios, enabling it to effectively extract events from diverse speech data.

What are the potential limitations of the current approach, and how could it be further improved to handle more challenging cases of event disentanglement

One potential limitation of the current approach is the challenge of event disentanglement in cases where events are closely intertwined or overlapping, leading to ambiguity in event extraction. To address this limitation and further improve the model's performance in handling complex cases of event disentanglement, several enhancements can be considered:

Fine-grained Event Representation: Enhance the model's ability to capture fine-grained event representations by incorporating hierarchical or attention mechanisms that focus on specific event components. This can help the model disentangle complex events with multiple sub-events or attributes.

Contextual Information Integration: Integrate contextual information from surrounding events or speech segments to provide additional context for disentangling events. Leveraging contextual embeddings or memory mechanisms can improve the model's understanding of event relationships and dependencies.

Adaptive Learning Strategies: Implement adaptive learning strategies that dynamically adjust the model's focus on different event components based on the complexity of the input data. Techniques such as reinforcement learning or meta-learning can help the model adapt its disentanglement process to varying scenarios.

Multi-modal Fusion: Incorporate multi-modal information, such as text or visual cues, to provide complementary signals for event disentanglement. Fusion techniques like multi-modal attention or cross-modal embeddings can enhance the model's ability to separate overlapping events.

By addressing these limitations and incorporating advanced techniques for event disentanglement, the Double Mixture method can achieve greater accuracy and robustness in handling challenging cases of event extraction from speech data.

Given the importance of continual learning in real-world applications, how could the insights from this work be applied to other speech-related tasks beyond event detection, such as speech recognition or synthesis

The insights from this work on continual event detection from speech can be applied to other speech-related tasks beyond event detection, such as speech recognition or synthesis, to improve their performance in dynamic and evolving environments. Here are some ways in which these insights can be leveraged:

Continual Speech Recognition: By adapting the Double Mixture method to the task of continual speech recognition, models can continuously learn new words, accents, or languages without forgetting previously learned speech patterns. This can enhance the accuracy and adaptability of speech recognition systems in diverse linguistic environments.

Continual Speech Synthesis: Applying the principles of continual learning to speech synthesis tasks can enable models to generate more natural and contextually relevant speech output over time. By incorporating memory mechanisms and adaptive learning strategies, models can improve the quality and fluency of synthesized speech across various domains and styles.

Multi-task Speech Processing: Extending the Double Mixture method to multi-task speech processing scenarios can allow models to perform multiple speech-related tasks simultaneously, such as event detection, recognition, and synthesis. This holistic approach can enhance the model's overall understanding of speech data and improve its performance across a range of speech processing applications.

By transferring the insights and methodologies from continual event detection to other speech-related tasks, researchers and practitioners can advance the capabilities of speech processing systems and create more robust and adaptive solutions for real-world applications.