Category Archives: Classification

Convolutional neural networks

Neural networks have been around for a number of decades now and have seen their ups and downs. Recently they’ve proved to be extremely powerful for image recognition problems. Or, rather, a particular type of neural network called a convolutional … Continue reading

Posted in Classification, Feature extraction | 3 Comments

Precision, Recall, AUCs and ROCs

I occasionally like to look at the ongoing Kaggle competitions to see what kind of data problems people are interested in (and the discussion boards are a good place to find out what techniques are popular.) Each competition includes a way … Continue reading

Posted in Classification | 3 Comments

Optimization

Optimization is a topic that has come up in a number of posts on this blog, but that I’ve never really addressed directly. So, I though it was about time that I gave it its own post. The term “optimization” … Continue reading

Posted in Classification, Regression | 3 Comments

Random forests

In last week’s post, I described a classification algorithm called a decision tree that defines a model/distribution for a data set by cutting the data space along vertical and horizontal hyperplanes (or lines in the two-dimensional example that we looked … Continue reading

Posted in Classification | 6 Comments

Decision Trees

In the last few posts, we explored how neural networks combine basic classification schemes with relatively simple distributions, such as logistic distributions with line/plane/hyperplane decision boundaries, into much more complex and flexible distributions. In the next few posts, I plan … Continue reading

Posted in Classification | 5 Comments

Neural Networks 3: Training

Note: I’ve started announcing new posts on twitter (@jejomath) for anyone who wants updates when new posts appear. In the last two posts, I described how a single neuron in a neural network encodes a single, usually simple, classifier algorithm, … Continue reading

Posted in Classification | 5 Comments

Neural Networks 2: Evaluation

In last week’s post, I introduced the Artificial Neural Network (ANN) algorithm by explaining how a single neuron in a neural network behaves. Essentially, we can think of a neuron as a classification algorithm with a number of inputs that … Continue reading

Posted in Classification | 12 Comments