# Monthly Archives: April 2014

## Shiny variance inflation factor sandbox

April 30, 2014
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In multiple regression, strong correlation among covariates increases the uncertainty or variance in estimated regression coefficients. Variance inflation factors (VIFs) are one tool that has been used as an indicator of problematic covariate collinearity. In teaching students about VIFs, it may be useful to have some interactive supplementary material so that they can manipulate factors affecting the uncertainty in...

## Registration now open for useR! 2014 in LA

April 30, 2014
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Join hundreds of other R users from around the world at the annual worldwide R user conference useR! 2014, to be held June 30 - July 3 at the UCLA campus in Los Angeles. Registration is now open for attendees. Advance registration for the conference is just $375 — and even less for academics ($250) and students (\$125). Register...

## How to do a silent install of R

April 30, 2014
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In this post, I’ll introduce how to do a silent install of R. Assume that you are a faculty member at an R course and need to prepare R environments for each students’ PC. In this case, you can install…Read more ›

## SMART Hackathon 2014

April 30, 2014
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Today is our SMART group's 2014 Hackathon! We will be at an undisclosed location, just plugging away at code/packages/apps. The mission statement: There's no structure except that you have to work on a software project and you have to present what you accomplished or didn't at a subsequent SMART meeting. We will be tweeting at

## A Shiny-app Serves as Shiny-server Load Balancer

April 30, 2014
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The Shiny-app on open-source edition Shiny-server has only one concurrent, which means it can run only for one user at a time point. But it can host multiple Shiny-apps, which can run synchronously. So, if we create severl Shiny-apps with different names but same function, then we can let more users use our service at same time. But users...

## Three Ways to Format R Code for Blogger

April 30, 2014
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Unformatted CodeIf you are like me originally then you might not think it is worth it to spend the extra energy to format your code.  After all people can just copy what you have and paste it into their preferred editor which will do its own forma...

## Decision making trees and machine learning resources for R

April 30, 2014
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I have recently come across Ricky Ho's blog "Pragmatic Programming Techniques", which seems to be excellent resource for all sorts of aspects regarding data exploration and predictive modelling. The post "Six steps in data science" provides a nice overview to some of the topics covered in the blog. For some reason, this blog does not seem to be...

## Automatically Scrape Flight Ticket Data Using R and Phantomjs

April 30, 2014
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I used to scrape static web pages with the R package RCurl. It’s a great package! When it comes to dynamic web pages, RCurl comes to be difficult to set up (actually, I never get it works). Then I met Phantomjs. PhantomJS is a headless WebKit scriptable with a JavaScript API. It has fast and native support for...

## colormap

April 30, 2014
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Introduction Over the past month or so I have been trying different ways of handling GMT-style colormaps in Oce. I think my present solution is on the right track, but I am posting here to get more eyes on the problem. Note that the function called Colormap() here will be called colormap() if I decided to incorporate it into Oce....