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Knowledge distillation

Training a student model using behavioural information from a teacher model or an ensemble of models.

Machine learning

What does the smaller model learn from its teacher?

Knowledge distillation trains a target model using behavioural information from a teacher model or group of models. This can include outputs or probability distributions. The target, also called a student model, is often smaller and is intended to perform the required task with lower operating demands. What transfers is behaviour for the chosen training tasks; a complete, identical body of knowledge does not follow. Quantisation instead changes the numerical representation of model values.

In a fictional project, a teacher model is to produce short routing notes for service messages, stating the request and missing information. The notes are checked against the original messages before being used as training material. If the teacher invents information or overlooks an existing detail, the target model could inherit that error. Later assessment uses different messages excluded from training. Their expected results are defined for the business task. This allows reviewers to examine whether required content is preserved and missing information continues to be treated as missing.

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