1. Speech recognition Koen en Hraban
Vowel.arff
Speech recognition
Koen en Hraban

2. Problem!
How do we make a computer recognize vowels in speech?

3. Let’s solve…
We record fifteen different people pronouncing 10 different vowels each.
We note features, like gender and more technical things.
After that, we store all the data in our extremely intriguing vowel.arff
We call in our little bird-friend WEKA, and let him do all the work for us…

4. We try:
Our decision stump didn’t really succeed quite well, so to speak… 11% accuracy.
How about a J48 then? We use 66% of the data to learn, and the rest to test. Nice: 71% accuracy.
BUT! We choose the best solution of course, as we are pioneers of the new knowledge!! It is:

5. CROSS-VALIDATION!!!
Now listen up, for the two people presenting this sheet will explain all the basics of this fine new genuine invention!!!

6. Results:
The decision stump was, of course, not the best way of predicting vowels. Though this was quite obvious from the beginning off.
The decision table, which we tried out in the mean time, did relatively well (68%) but far not enough for our research.
In the end we tried a few J48 trees:
Percentage split, 66%: it was 71% accurate. Nice, just not enough.
Cross validation? 10 folds: 81%!! That is very nice, don’t you agree? 4 out of 5 vowels are recognized correctly, all through ones and zeros… ain’t the technology just wonderful?!