July 2012

Linear programming in R: an lpSolveAPI example

July 14, 2012 | Bart

First of all, a shout out to R-bloggers for adding my feed to their website! Linear programming is a valuable instrument when it comes to decision making. This post shows how R in conjunction with the lpSolveAPI package, can be used to build a linear programming model and to analyse  ... [Read more...]

Processing Public Data with R

July 13, 2012 | pssguy

I use R aplenty in analysis and thought it might be worthwhile for some to see the typical process a relative newcomer goes through in extracting and analyzing public datasets In this instance I happen to be looking at Canadian air pollution statistics. The data I am interested in is ... [Read more...]

Applications of R at Google

July 13, 2012 | David Smith

At a talk I saw at the useR!2012 conference last month, Googler Karl Millar estimated that there are at least 200 active R users at Google, plus another 300+ occasional users participating in Google's internal R support list. But what are all these Google employees doing with R? A post from the ... [Read more...]

influence.ME updated to version 0.9

July 13, 2012 | Rense Nieuwenhuis

Influence.ME is an R extension package for R that provides tools for detecting influential data in multilevel regression models. It is developed by Rense Nieuwenhuis (that’s me), Manfred te Grotenhuis, and Ben Pelzer. Recently, a new version (0.9) was uploaded ... [Read more...]

Dynamical systems: Mapping chaos with R

July 13, 2012 | Corey Chivers

Chaos. Hectic, seemingly unpredictable, complex dynamics. In a word: fun. I usually stick to the warm and fuzzy world of stochasticity and probability distributions, but this post will be (almost) entirely devoid of randomness. While chaotic dynamics are entirely deterministic, their sensitivity to initial conditions can trick the observer into ... [Read more...]

1-Month Reversal Strategy

July 12, 2012 | systematicinvestor

Today I want to show a simple example of the 1-Month Reversal Strategy. Each month we will buy 20% of loosers and short sell 20% of winners from the S&P 500 index. The loosers and winners are measured by prior 1-Month returns. I will use this post to set the stage for ... [Read more...]

RcppArmadillo 0.3.2.4

July 12, 2012 | Thinking inside the box

Conrad released version 3.2.4 of Armadillo yesterday. It contains a workaround for g++ 4.7.0 and 4.7.1 which have a regression triggered by the Armadillo codebase for small fixed-sized matrices. The corresponding RcppArmadillo package 0.3.2.4 arrived ... [Read more...]

Napa Valley wine tasting map: interactive version

July 12, 2012 | David Smith

Got some great reactions to the Napa Valley wine tasting map made with the ggmap package I posted on Monday. A couple of people asked if similar maps could be made for other wine regions (like Australia's Hunter Valley, or the Walla Walla region in Washington): provided you have a ... [Read more...]

Using discrete-event simulation to simulate hospital processes

July 12, 2012 | Bart

Discrete-event simulation is a very useful tool when it comes to simulating alternative scenario’s for current of future business operations. Let’s take the following case; Patients of an outpatient diabetes clinic are complaining about long waiting times, this seems to have an adverse effect on patient satisfaction and ... [Read more...]

R scripts for downloading iButton Thermochron dataloggers

July 11, 2012 | Luke Miller

Last time, I posted some R code to help quickly launch many iButton Thermochron temperature dataloggers with the same mission parameters. The R code makes use of a publicly-available command line utility released by the iButton’s manufacturer, Maxim.  Of course, Maxim also has a command line utility for downloading ... [Read more...]

Rcpp is smoking fast for agent-based models in data frames

July 11, 2012 | gary

In a previous post, I discussed different approaches to speeding up some loops in data frames. In particular, R data frames provide a simple framework for representing large cohorts of agents in stochastic epidemiological models, such as those representing disease … Continue reading → [Read more...]

Bridget Riley exhibition in London

July 11, 2012 | Markus Gesmann

The other day I saw a fantastic exhibition of work by Bridget Riley. Karsten Schubert, who is Riley's main agent, has a some of her most famous and influential artwork from 1960 - 1966 on display, including the seminal Moving Squares from 1961.Photo of...
[Read more...]
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