Tuesday, May 19, 2015

After submitting the 1st paper of my PhD to a journal

[I got this image from Kostas Siozios]

Paper submitted ! Hoping it finds the reviewers in good mood.

Monday, May 18, 2015

The Sunrise on Twitter

Simon Rogers (former data editor at Twitter) has created a few months ago this great map that shows Twitter users tweeting the word 'Sunrise' in the world's most-spoken languages on a typical day. This is a nice way of using Twitter to capture the pulse of the planet throughout throughout a 24 hours period and getting some nice data visualizations.

It is quite clear, though, that we still have a long way to go before being able to use social network analytics to address the big challenges of humanity without being fooled by the traps of these kind of data. We might get there one day, or maybe humanity will be slaved by artificial intelligence before then and we will not have to worry about that.

Saturday, May 16, 2015

How many authors can fit in a paper? 2

In case you don't remember this post, here is my rule of thumb to decide the maximum number of authors of an academic paper: "The list of authors should not be longer than the abstract."

A recently published paper in genomics with more than 1,000 authors has sparked a discussion about the meaning of authorship over the past few months. Now we have a new record!

Thursday, May 14, 2015

An Overlay of Times and Spaces in Boston

We have seen a few time-lapse videos in this blog before but this one is different. The photographer Julian Tryba overlays different footages at different times of the day to create what she calls a 'Layer-Lapse'. Check her Boston Layer-Lapse.

Monday, May 11, 2015

A Simple Index to compare Urban Centrality: Mono vs Polycentric Cities

warning: this post contains self-promotion.

Pereira, R. H. M., Nadalin, V., Monasterio, L., Albuquerque, P. H. M. (2013). Urban Centrality: A Simple Index. Geographical Analysis. doi:10.1111/gean.12002
Abstract: This study introduces a new measure of urban centrality. The proposed urban centrality index (UCI) constitutes an extension to the spatial separation index. Urban structure should be more accurately analyzed when considering a centrality scale (varying from extreme monocentricity to extreme polycentricity) than when considering a binary variable (monocentric or polycentric). The proposed index controls for differences in size and shape of the geographic areas for which data are available, and can be calculated using different variables such as employment and population densities, or trip generation rates. The properties of the index are illustrated with simulated artificial data sets and are compared with other similar measures proposed in the existing literature. The index is then applied to the urban structure of four metropolitan areas: Pittsburgh and Los Angeles in the United States; São Paulo, Brazil; and Paris, France. The index is compared with other traditional spatial agglomeration measures, such as global and local Moran's I, and density gradient estimations. 

Here is the ungated versionn of the paper. 

Wednesday, April 29, 2015

Biographical note: On the Road

The Blog has been less active than usual because I'm on the road these days. I was at the AAG Conference in Chicago last week and I'm in Berkeley this week*. The level of activity will remain lower than usual next week, when I'll be in Greece for a workshop on Transportation Equity.

* By the way, this is the view from 'my office' today at Berkeley library.

[Rafael Pereira, me]

Fatalities from car accidents per billion kilometers