i’m currently working on a project regarding isolated word recognition using svm model. But i’m struck by the scenario to decide an unknown word that put into the model belongs to my specific list of words or not. In more detail, i have a model that could recognize 5 vietnamese words, and the voice signal of words that aren’t in any of these classes will be classify into class 6 (non-key class), but the real training samples i could get for this class can’t cover all the real cases in real life. So my question is how to efficiently differentiate between this class and the others.