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  • Continued from Flat-start:

    Once we have trained decent seed models in the flat-start stage of the training process, we can then train the models on a larger training set. For this we simply need to replace the feature file list and the model label file with the appropriate files in the parameter file and use:

    hmm_train -p params.text -c CI

  • Creating the Short Pause Model:

    In the data preparation section of this tutorial, we saw that the short pause (sp) model was a dummy model. In this stage we train this model. Typically, the "sp" model has a single state and is tied to the middle state of the "sil" model. This can be simply done by setting the central state of the sp model in the model definition file to the central state of the silence model from the last step. The steps involved for our example follow:

    Assign a new transition matrix (index 30 is the next one in this case) for the "sp" model.

    In the transitions file generated at the end of the last training iteration increment the transition matrix count by one and add a new 3x3 matrix with index chose above (index 30). Initialize it to:

    0.000000e+00 5.000000e-01 5.000000e-01
    0.000000e+00 5.000000e-01 5.000000e-01
    0.000000e+00 0.000000e+00 0.000000e+00


  • Training with the Short Pause Model:

    Once the "sp" model has been initialized, we use word labels of the training data to train the models. Note that while training with word transcriptions, a couple of changes need to be made to the parameter file to be used with hmm_train.

    • Change the mlf_file tag to point to the word label file.

    • Set the mlf_mode tag to "word_mlf" instead of "model_mlf".


    With these changes made, the new parameter file should appear similar to this.

    Use hmm_train to start training. About four iterations of training should be done in this stage. The process is shown as a flow graph below.
    sp model



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