Classification 4: Many Species Classification
This trial was focused on expanding the network to include
more species of birds than the previous networks. A similar network to the
basic network described above was built with the exception that the output
and hidden axons both contained eight neurons. This change was made to
accommodate the eight species selected for this trial. The birds selected
were the Black Cap Chickadee, Bewick's Wren, Northern Flicker, House Finch,
Purple Finch, Acadian Flycatcher, Dark-eyed Junco and Violet-green Swallow.
These birds were selected for the availability of sample recordings. The
testing of this network showed less favourable results than previous trials.
After several networks were trained and tested, perfect classification was
never observed. While the Northern Flicker proved the most difficult to
classify, the other species were misclassified in an apparently random
fashion from network to network.
In order to improve results, the number of neurons in
the hidden layer was increased to fifteen. The test results of this new
network showed that all species except the Northern Flicker and Black Cap
Chickadee were consistently classified correctly. The Northern Flicker
continued to be misclassified in most tests, but perfect classification
was seen in 10% of runs. Increasing the number of neurons in the hidden
layer to twenty allowed the network to train itself much faster than the
previous network as seen in, but the results obtained in the testing phase
Next the number of hidden layers in the network was
increased to two. The first hidden axon was given twenty neurons and
the second was given fifteen. Testing showed that perfect classification
was achieved in approximately 40% of the networks trained, with the same
two species as noted above being responsible for all misclassifications.
This required more epochs to train, and due to the greater number of
synapses, took longer to run each epoch.