What is Knowledge Distillation? A Deep Dive.

Tags

Top Highlights

• The concept of knowledge distillation is based on the observation that a complex neural network not only learns to make accurate predictions but also learns to capture meaningful and useful representations of the data. These representations are learned by the hidden layers of the neural network and can be thought of as "knowledge" acquired by the network during the training process.

• The intuition behind this approach is that the teacher network's predictions are based on a rich and complex representation of the input data, which the student network can learn to replicate through the distillation process.

• One of the key benefits of knowledge distillation is that it can significantly reduce the memory and computational requirements of a model while maintaining similar performance to the larger model.

• Generally, there are three types of knowledge distillation, each with a unique approach to transferring knowledge from the teacher model to the student model. These include: Response-based distillation; Feature-based distillation, and; Relation-based distillation.

• However, response-based knowledge distillation has its limitations. For example, this technique only transfers knowledge related to the teacher model's predicted outputs and does not capture the internal representations learned by the teacher model. Therefore, it may not be suitable for tasks that require more complex decision-making or feature extraction.

• In feature-based knowledge distillation, the student model is trained to mimic the internal representations or features learned by the teacher model. The teacher model's internal representations are extracted from one or more intermediate layers of the model, which are then used as targets for the student model. During the distillation process, the teacher model is first trained on the training data to learn the task-specific features that are relevant to the task at hand. The student model is then trained to learn the same features by minimizing the distance between the features learned by the teacher model and those learned by the student model.

• One of the main advantages of feature-based knowledge distillation is that it can help the student model learn more informative and robust representations than it would be able to learn from scratch. This is because the teacher model has already learned the most relevant and informative features from the data, which can be transferred to the student model through the distillation process.

• In relation-based distillation, a student model is trained to learn a relationship between the input examples and the output labels. In contrast to feature-based distillation, which focuses on transferring the intermediate representations learned by the teacher model to the student model, relation-based distillation focuses on transferring the underlying relationships between the inputs and outputs.

• There are three primary techniques available for training student and teacher models: Offline; Online, and; Self Distillation

• less attention given to the design of the teacher network architecture. This approach has allowed for the transfer of knowledge from pre-trained and well-performing teacher models to student models, improving overall model performance.

• the teacher model is updated continuously with new data, and the student model is updated to reflect this new information. The process of online knowledge distillation involves the teacher model and the student model being trained simultaneously.