# Blog Archives

## Weekend at Bernoulli’s

June 1, 2014
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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...

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

October 16, 2013
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(This article was first published on David Chudzicki's Blog, and kindly contributed to R-bloggers) This post will describe a way I came up with of fitting a function that’s constrained to be increasing, using Stan. If you want practical help, standard statistical approaches, or expert research, this isn’t the place for you (look up “isotonic regression” or “Bayesian isotonic...

## Weak Learners

August 20, 2013
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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...

## Fun with Fremont Bridge Bicyclists

June 27, 2013
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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...

## Visualize a random forest that classifies digits

August 5, 2012
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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...

## Visualizing ChaLearn Gestures Test Data

December 19, 2011
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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...

## Visualizing Gestures as Paths

December 11, 2011
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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...

## pre-generate pictures of your knitting

April 18, 2011
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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...

## Installing R on Amazon Linux

February 13, 2011
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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...

## Animation from Kaggle traffic prediction competition

January 2, 2011
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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...