## highlight 0.2-0

May 31, 2010
By

I've released version 0.2-0 of highlight to CRAN This version brings some more additions to the sweave driver that uses highlight to produce nice looking vignettes with color coded R chunks The driver gains new arguments boxes, bg and border to c...

## Bike The Drive 2010

Memorial Day weekend is also time for the annual Bike The Drive in Chicago. This time only half the household got up bright and early and enjoyed Lakeshore Drive free of cars. A highly recommended event.

## Betting on Pi

May 31, 2010
By

I was reading over at math-blog.com about a concept called numeri ritardatari. This sounds a lot like “retarded numbers” in Italian, but apparently “retarded” here is used in the sense of “late” or “behind” and not in the short bus sense. I barely scanned the page, but I think I got the gist of it:

## A data visualization manifesto

May 31, 2010
By

Details matter (at least, they do for me), but we don't yet have a systematic way of going back and forth between the structure of a graph, its details, and the underlying questions that motivate our visualizations. (Cleveland, Wilkinson, and....

## JPM Chase Corporate Challenge 2010

It's Memorial Day weekend so it was time for the Chicago's JP Morgan Chase Corporate Challenge on Thursday. The weather was glorious, the usual 20-some thousand runners participated and a good time was had. Work had arranged for a nice tent, food, mu...

## Example 7.39: Nelson-Aalen estimate of cumulative hazard

May 31, 2010
By

In our previous example, we demonstrated how to calculate the Kaplan-Meier estimate of the survival function for time to event data. A related quantity is the Nelson-Aalen estimate of cumulative hazard. In addition to summarizing the hazard incurred ...

## Simulating a Queue in R

May 30, 2010
By

In the GCaP class earlier this month, we talked about the meaning of the load average (in Unix and Linux) and simulating a grocery store checkout lane, but I didn't actually do it. So, I decided to take a shot at constructing a discrete-event simulatio...

## Talk at CRiSM

May 30, 2010
By

This is the talk I am giving at the workshop on model uncertainty organised by the Centre for Research in Statistical Methodology (CRiSM) at the University of Warwick, on May 30-June 1. Careful readers will notice there is not much difference with my previous talk on the topic, as I only included the Savage-Dickey slides

## Dynamic Modeling 2: Our First Substantive Model

May 30, 2010
By

(This is the second of a series of ongoing posts on using Graph Algebra in the Social Sciences.) First-order linear difference equations are powerful, yet simple modeling tools.  They can provide access to useful substantive insights to real-world phenomena.  They can have powerful predictive ability when used appropriately.  Additionally, they may be classified in any number

## Notice that even though output is in a log scale, output is…

May 29, 2010
By

Notice that even though output is in a log scale, output is shooting up in an exponential way. DATA from Brad DeLong

## Source Code Files in R

May 29, 2010
By

R's interactive programming style is similar to what I have seen in other environments (e.g. ruby's irb and Oracle's SQL*Plus, etc). There are a few commands that you need to be aware of to get up and running with developing R programs.To identify yo...

## Weekend art in R (part 1?)

May 29, 2010
By

As usual click on the image for a full-size version. Code: par(bg="black") par(mar=c(0,0,0,0)) plot(c(0,1),c(0,1),col="white",pch=".",xlim=c(0,1),ylim=c(0,1)) iters = 500 for(i in 1:iters) { center = runif(2) size = rbeta(2,1,50)   # Let's create random HTML-style colors color = sample(c(0:9,"A","B","C","D","E","F"),12,replace=T) fill = paste("#", paste(color[1:6],collapse=""),sep="") brdr = paste("#", paste(color[7:12],collapse=""),sep="")   rect(center[1]-size[1], center[2]-size[2], center[1]+size[1], center[2]+size[2], col=fill, border=brdr, density=NA, lwd=1.5) }

## highlight 0.1-9

May 29, 2010
By

The version 0.1-8 of highlight introduced a small bug in the latex renderer. This is now fixed in version 0.1-9 and the latex renderer also gains an argument "minipage" which wraps the latex code in a minipage environment. I've used this to make...

## Syncing files across computers using DropBox

May 29, 2010
By

Motivation In the past few months I have been using DropBox for syncing my work files between my home and work computer. It has saved me from numerous mistakes and from sending the files to myself via e-mail. Recently I found this service highly useful for sharing files with 4 other people with whom I am working on a...

## An XML Representation of the Keys to Soil Taxonomy?

May 28, 2010
By

Western Fresno Soil Hierarchy: partial view of the hierarchy within the US Soil Taxonomic system Maybe this is just craziness, but wouldn't be neat to have an XML formatted version of the Keys to Soil Taxonomy? The format might look something like the ...

## R: More plotting fun with Poission

May 28, 2010
By

Coded as follows: x = seq(.001,50,.001) par(bg="black") par(mar=c(0,0,0,0)) plot(x,sin(1/x)*rpois(length(x),x),pch=20,col="blue")

## Tuesday’s child is full of probability puzzles

May 28, 2010
By

COUNTERINTUITIVE PROBLEM, INTUITIVE REPRESENTATION Blog posts about counterintuitive probability problems generate lots of opinions with a high probability. Andrew Gelman and readers have been having a lot of fun with the following probability problem: I have two children. One is a boy born on a Tuesday. What is the probability I have two boys? The

## Dynamic Modeling 1: Linear Difference Equations

May 28, 2010
By

(This is the first in a series on the use of Graph Algebraic models for Social Science.) Linear Difference models are a hugely important first step in learning Graph Algebraic modeling.  That said, linear difference equations are a completely independent thing from Graph Algebra.  I’ll get into the Graph algebra stuff in the next post or

## Must Have Software

May 28, 2010
By

Having worked with Unix (BSD, HPUX, IRIX, Linux and OSX), Windows (NT4, 2000, XP, Vista and 7) for quite a while I have seen a lot of different software tools. I would like to quickly exhibit my “must have” list. These are the packages that I find to be the single “must have offerings” in Related posts:

## Creating surface plots

May 28, 2010
By

A 3d wireframe plot is a type of graph that is used to display a surface – geographic data is an example of where this type of graph would be used or it could be used to display a fitted model with more than one explanatory variable. These plots are related to contour plots which

## Because it’s Friday: The dating equation

May 28, 2010
By

According to internet lore, there's a mathematical equation that governs the lower bound for the socially acceptable age of a potential dating partner: half your age plus 7, or, in mathematical terms, if x is your age then the lower bound is f(x) = x/2 + 7. Seems simple, right? if you're 20, then the minimum socially acceptable age...

May 28, 2010
By

## Rmetrics 2010

May 28, 2010
By

The 4th User/Developer Meeting on computational Finance and Financial Engineering (Rmetrics 2010) will take place once again in Meielisalp. This is the first time I'll attend the conference, but I'm not coming empty handed. I'll present the wo...

## A repulsive random walk

May 28, 2010
By
$A repulsive random walk$

Matt Asher posted an R experiment on R-bloggers yesterday simulating the random walk which has the property of avoiding zero by quickly switching to a large value as soon as is small. He was then wondering about the “convergence” of the random walk given that it moves very little once is large enough. The values

## The guessing game in R (with a twist, of course)

May 27, 2010
By

Maybe you remember playing this one as a kid. If you are about my age, you may have even created a version of this game as one of your first computer programs. You guess a number, the computer tells you if you if you are too low or high. I’ve limited the number of maximum

## Getting Parent Material Data out of SSURGO

May 27, 2010
By

Parent material data is stored within the copm and copmgrp tables. The copm table can be linked to the copmgrp table via the 'copmgrpkey' field, and the copmgrp table can be linked to the component table via the 'cokey' field. The following queries illustrate these table relationships, and show one possible strategy for extracting the parent material information...

May 27, 2010
By

After finishing the R prototype for data visualization, I've started abstracting the various methods necessary to create beautiful graphs. While there's no preliminary version of the R package yet, I think I've taken a number of exciting steps. These include: Abstracting graph objects. Objects such as lines, scatter plots, and other graph types can all

May 27, 2010
By