Articles by David

Weekend at Bernoulli’s

June 1, 2014 |

I have been doing some background reading on group sequential trials for an upcoming project. One of the papers I came across in terms of the required numerical methods is "Repeated Significance Tests on Accumulating Data" (Armitage, et al, 1969). In t... [Read more...]

A Bayesian Model for a Function Increasing by Chi-Squared Jumps (in Stan)

October 16, 2013 |

Weak Learners

August 20, 2013 |

Tonight's session of R bore just enough fruit that I finally am writing my sophomore entry. I was browsing the slides from a machine learning lecture given by Leo Breiman and came across a relatively simple example he used to introduce the notions... [Read more...]

Fun with Fremont Bridge Bicyclists

June 27, 2013 |

Given the title of this post and its proximity to the Solstice, you will be disappointed to know that I am not writing about naked bicyclists. I apologize for any false hope I may have instilled in you.On October 11th, 2012, the city of Seattle, WA beg... [Read more...]

Visualize a random forest that classifies digits

August 5, 2012 |

My last post uses random forest proximity to visualize a set of diamond shapes (the random forest is trained to distinguish diamonds from non-diamonds).This time I looked at the digits data set that Kaggle is using as the basis of a competition for "ge... [Read more...]

Visualizing ChaLearn Gestures Test Data

December 19, 2011 |

The colored paths are labeled training data, just like in my last post on this.The title gives the "answer" for a test video:Could you tell from just this what the sequence of gestures was?Not perfectly, but way better than chance.See a couple more exa... [Read more...]

Visualizing Gestures as Paths

December 11, 2011 |

Kaggle is hosting an exciting new competition in which the object is to learn to identify sequences of gestures from just one example of each gesture. I would bet this competition has a lot of potential to attract academics interested in machine learni... [Read more...]

April 18, 2011 |

[Update: I've made a website for this: http://www.plannedpooling.com/.]This was a birthday present for my spouse. (Don't worry--I also covered a lot of things -- fruit/nuts/cocoa puffs/etc -- in chocolate. But I think both were appreciated!)Sometimes p... [Read more...]

Installing R on Amazon Linux

February 13, 2011 |

When I wanted to run R (statistical software) on the Amazon "cloud", the first thing I found was this post explaining how to launch an Amazon EC2 "instance" (virtual machine) and pointing to an "image" (contains operating system and whatever else you w... [Read more...]

Animation from Kaggle traffic prediction competition

January 2, 2011 |

Below: two animations (same one twice, just as different speeds) I made from the highway data for the Kaggle traffic prediction competition.The data are travel times for 61 different sections of Sydney's M4 freeway, in both directions. The data comes i... [Read more...]