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1 Why Machine Learning Strategy

Machine learning is the foundation of countless important applications, including web
search, email anti-spam, speech recognition, product recommendations, and more. I assume
that you or your team is working on a machine learning application, and that you want to
make rapid progress. This book will help you do so.

Example: Building a cat picture startup

Say you’re building a startup that will provide an endless stream of cat pictures to cat lovers.

You use a neural network to build a computer vision system for detecting cats in pictures.

But tragically, your learning algorithm’s accuracy is not yet good enough. You are under

tremendous pressure to improve your cat detector. What do you do?

Your team has a lot of ideas, such as:

• Get more data: Collect more pictures of cats.

• Collect a more diverse training set. For example, pictures of cats in unusual positions; cats

with unusual coloration; pictures shot with a variety of camera settings; ….

• Train the algorithm longer, by running more gradient descent iterations.

• Try a bigger neural network, with more layers/hidden units/parameters.

Page 6 Machine Learning Yearning-Draft Andrew Ng