Seeing how one might construct a Signal Quality Index for ECG using data from the CinC 2011 challenge. A culminating project showing how one of the latest nonlinear dimensionality reduction techniques, the Diffusion Map or Laplacian Eigenmap, performs on short windows of real life signal data. Click here for the summary presentation. The plots are fully interactive! The presentation brings a lot of data to the table, so please give it a few seconds to get ready before going forward through the slides.