Introduction



Data & Labeling



Feature Extraction



Models



Application



Results










Summary of Results: 

The following values indicate percentage of correctly classified messages given all the available data. We have acquired these percentages using leave-one-out cross validation testing on all the data.

 

model 

Happy(40) Sad(27) Calm(84) Excited(77) Urgent(46) Not Urgent(140) Formal(98) Informal(150)
GMM         N=1 Diagonal 75 44 76 52 35 70 73 44
GMM         N=1 Full 87 11 79 68 17 92 60 59
GMM         N=2 Diagonal 65 37 75 67.5 37 63.5 49 68
GMM         N=4 Diagonal 70 37 74 62 37 68.5 64 57
GMM         N=2 Full NA NA 74 57 NA NA 37 65
HMM N=3 Fully Connected 79 73 67 67 66 76 68 64

* We have experimented with HMMs with different states and saw that 3 states provided optimal results. Due to the lengthy process of cross-validation, we did not perform tests on all the data for these cases.

 

Conclusions:

  • Happy, Sad and Urgent, Not Urgent were not separable using the global features and GMMs. HMMs were able to discriminate the data in these cases.

 

  • Both the GMM and HMM were able separate formal and informal, with HMMs performing slightly better. (5%)

 

  • GMM with 2 mixtures or single mixture with full covariance was able to separate the activation axis (calm, excited) slightly better than the HMM. This hints at the fact that formality and activation are somewhat related to global characteristics of the speech signal , while urgency and valence are reflected in local transitions.