As you may now, Apple introduced Core ML for iOS 11 in this year's WWDC. This framework makes use of an already trained ML model in an specific format that you can convert if your source model doesn't match it. Apple also makes available for downloading and directly integratiing some already trained ML models here.
On the other hand, they also mentioned at the WWDC 2017 that you can train model by using tools such as Caffe or Keras.
I'd like to train a model with a more specific purpose than the ones already trained and provided by Apple, that look quite generic ones. But I'm not an ML expert and I'd appreciate an starting point for this.
Where can I find models that I can train? And then, how can I train them? I'm looking for some posts or tutorials for this with no success. I read some posts like this one, but it doesn't provide the guidelines I need.
You will find pretrained (CNN) Keras models documented here: https://keras.io/applications/
The Keras blog is a good starting point too: https://blog.keras.io/category/tutorials.html
And these are very good tutorials: http://machinelearningmastery.com/start-here/