James Keirstead

Book review: The Evolution of Great World Cities

A fascinating new book on urban economics, infrastructure, and the links between them.

Grrr…

I’ve been working through Gelman et al.’s otherwise excellent Bayesian Data Analysis and it’s going reasonably well. My statistics is a little bit rusty so it’s taken time to work through all of the exercises and really understand what’s going on. But I say “otherwise excellent” because yesterday I spent ages trying to figure out a problem, only to discover that the data published in the book don’t correspond to the text discussion.

Sampling for Monte Carlo simulations with R

I've knocked together a quick function for generating efficient Monte Carlo samples. It takes a bit of the legwork out of running Monte Carlo simulations.

Announcing Lectures, my first GitHub project

I've recently shifted from SVN to Git for version control and it's working great. In fact, I've just finished my first project which lets you easily build slides and notes for lectures.

Getters and setters in R

When I first started using R, one of the things that attracted me was its claim to be an object-oriented programming (OOP) language. Coming from a Java background, I was used to designing software with OOP concepts like encapsulation and inheritance but, when I turned my hand to R, I quickly realized that “object-oriented” meant something subtlely different.

Read more on Getters and setters in R…

Positive coefficient regression in R

Ever have a regression model where the coefficients don't make sense? I've been trying to predict electricity and gas consumption from daily activity schedules but a simple linear regression kept saying that demands should go down the more an activity is performed. Fortunately I found the nnls package and show here how you can use it to ensure that your regression coefficients stay positive.

Slopegraphs in R

The internet seems abuzz this week with the "discovery" of a long-lost Edward Tufte plot type: the slopegraph. In this post, I'll show you how to create these elegant compact plots using R and ggplot2.

CHP planning restrictions and the efficiency of urban energy systems

We have a new paper out that looks at how planning restrictions on the use of combined heat and power might affect the overall energy efficiency of an urban energy system. The method is the key innovation here, as we use a series of generic city designs together with an integer programming optimization model to identify some general design principles.

Britain’s Low Carbon Rush Hour

Do you cycle to work? How about drive the kids to school? Or maybe hop a bus downtown for an early morning coffee with a friend? Whatever it is you're doing, these trips all contribute to the carbon footprint of Britain's rush hour. Here's a closer look at some of the results from our recent study of commuting patterns in Britain.

Review: The God Species by Mark Lynas

Mark Lynas's new book is an excellent introduction to a pragmatic view of environmental problems. But it also contains a tale of how the environmental movement uses science in its campaigns, a story that deserves to be told at greater length.