Monday, December 30, 2013

When Social Networks meet Public Transport

Among the Best Scientific Visualizations of 2013 (by Brandon Keim), one particular paper attracted my attention as the authors analyze the encounter network of bus passengers in Singapore. Here is the paper:

[image credit: Sun et al, 2013]

Understanding metropolitan patterns of daily encounters." By Lijun Sun, Kay W. Axhausen, Der-Horng Lee, Xianfeng Huang. Proceedings of the National Academy of Sciences, Vol. 110 No. 34, August 20, 2013.

Understanding of the mechanisms driving our daily face-to-face encounters is still limited; the field lacks large-scale datasets describing both individual behaviors and their collective interactions. However, here, with the help of travel smart card data, we uncover such encounter mechanisms and structures by constructing a time-resolved in-vehicle social encounter network on public buses in a city (about 5 million residents). Using a population scale dataset, we find physical encounters display reproducible temporal patterns, indicating that repeated encounters are regular and identical. On an individual scale, we find that collective regularities dominate distinct encounters’ bounded nature. An individual’s encounter capability is rooted in his/her daily behavioral regularity, explaining the emergence of “familiar strangers” in daily life. Strikingly, we find individuals with repeated encounters are not grouped into small communities, but become strongly connected over time, resulting in a large, but imperceptible, small-world contact network or “structure of co-presence” across the whole metropolitan area. Revealing the encounter pattern and identifying this large-scale contact network are crucial to understanding the dynamics in patterns of social acquaintances, collective human behaviors, and—particularly—disclosing the impact of human behavior on various diffusion/spreading processes.

Friday, December 27, 2013

Tuesday, December 24, 2013

Happy Holidays

A couple of centuries ago, a man was born who changed the course of history. Happy Birthday Isaac Newton!

[image credit: ?]

In the spirit of Christmas, I have two gifts to share with my hundreds of thousands of readers out there:

A song, by Ali Farka Toure:

And a short video about Christmas:

Sunday, December 22, 2013

2013 World Population Data Sheet

Here is the PRB's 2013 World Population Data Sheet. You may also take a look at their webinar or this interactive infographic highlighting some key population trends.  More of the same 

Chart of the Day

Wednesday, December 18, 2013

Peer effect + Neighborhood effect

The interaction of Peer and Neighborhood effects of Bart Simpson, aka 'The Cone of Ignorance' (via FlowingData).

[Image Credit: FlowingData]

Monday, December 16, 2013

Sunday, December 15, 2013

Urban Picture

Manhattan (1944), by Andreas Feininger.


Bonus: Central Park

[Image Credit: ? via @GoogleEarthPics]

Thursday, December 12, 2013

Equity Issues in Transport Policy

As some of you may know, I have just started my PhD and I will be focusing on 'Equity Issues in Transport Policies' with bits of spatial and demographic analysis.

So I was very glad to watch this short talk by Enrique Peñalosa (former mayor of Bogota): 'Why buses represent democracy in action'. You know, it's always good to hear big names saying you're working on important problems.

Tuesday, December 10, 2013

The Geography of Nobel Prize winners

Using Online images to map urban perception

Ricardo Dagnino emailed me months ago! a link to a very inventive research project that uses online images and crowdsourcing to map urban perception. The project is called Place Pulse and it is conducted by Cesar Hidalgo and his colleagues at the MIT Media Lab.

Here is how the research method works and the project webpage . By the way, take one minute to support the project with some clicks.

And here is one paper they published this year: 

The Collaborative Image of The City: Mapping the Inequality of Urban Perception, by P. Salesses, K. Schechtner and C. Hidalgo. published at PLOS one

ps. They have a Video Abstract.

Monday, December 9, 2013

Urban Modelling back in 1976

The other day I was wandering in the library when I bumped into the book Urban Modelling: Algorithms, Calibrations, Predictions, published by M. Batty back in 1976 (!). Since then, he and his team at CASA have made many contributions to the field of urban studies with new modelling developments and applications.

Some of the softwares developed at CASA (including GMap Creator) are available for download here. You can play with your own Von Thunen Model!

[Image Credit: CASA]

Related Links:

Thursday, December 5, 2013

Personalized Doodle

Today I got my first Personalized Doodle!

It took me a few minutes to understand that my Google frontpage was actually celebrating my birthday and not someone else's. Those guys at NSA Google are doing a great job!

[Thanks NSA Google]


Sunday, December 1, 2013

Biographical note: a visit to Leviathan

Quite often, I'm amazed at how old Oxford University is. My College (St Edmund Hall, aka Teddy Hall) dates back to the 13th Century and some of its oldest buildings date from the 12th and 17th centuries.

Last week, I took a short tour visit to the Old Library of my College to see the 1st edition of Leviathan, pubished in 1651 by Thomas Hobbes. My Social Scientists readers know how special this book is and you can probably imagine how I felt like a kid in a candy store!

ps. I thank the dedicated librarians at Teddy Hall who were very kind to receive me in their 'office' to talk about their work.

Assorted Links

Friday, November 29, 2013

What is Aging (from a biological perspective)

A nice and short video by PhD TV and Joao Pedro De Magalhaes showing a biological perspective on aging (ht Marcia Castro).

Tuesday, November 26, 2013

off-topic: An instagram short film

It's been a while since I don't post any time-lapse videos. But this video here is special because it takes the time-lapse idea in reverse. Instead of taking sparse pictures of one same scene, it takes instagram pictures taken by different people in separate moments and gathers them as if they were one single scene. Nice work by Thomas Jullien (ht Felipe Seigman)

Monday, November 25, 2013

The determinants of agglomeration in Brazil: input-output, labor and knowledge externalities

Aguinaldo Maciente is a great colleague of mine at Ipea. He finished his PhD at Illinois (Urbana-Champaign) a few months ago. It could be particularly interesting to those readers working in Regional Science, Migration studies, Labor Markets and Geographic Labor Mobility.

Thesis: The determinants of agglomeration in Brazil: input-output, labor and knowledge externalities.

This research investigates industry agglomeration and coagglomeration patterns in Brazil, and assesses their association with the Marshallian forces that are commonly viewed as sources of agglomeration economies, namely the input-output and labor pooling externalities. Knowledge externalities, the third classic source of Marshallian agglomeration economies, are partially captured through labor-embodied knowledge usage. [...] The ONET database, which contains several skill measures for US occupations, is matched with Brazilian occupations and factor analysis is used to produce a set of ONET skill and knowledge groups. These skills groups are intended to describe the labor profile of industries and regions and constitute the basis for measures of labor and labor-embodied knowledge externalities for pairs of industries. The measures of input-output linkages and labor-use similarity are related to the observed agglomeration and coagglomeration patterns, in order to test for the possible sources of agglomeration economies in Brazil. Results indicate that Brazil has agglomeration levels, as measured by Ellison and Glaeser’s (1997) agglomeration index, that are slightly decreasing over time, but comparable to the international experience. However, the components of the agglomeration index reveal that Gini-type regional employment concentration and plant-level employment concentration are relatively high, despite their decrease from 1994 to 2010. That is, Brazil has most of its employment concentrated into relatively fewer regions and plants, when compared to results found in the literature, for example, for the United States. [...] Overall colocation patterns in Brazil seem to be more associated with labor and labor-embodied knowledge externalities than with input-output externalities. Natural advantages, such as agricultural and mining potential and road density are also positively associated with observed coagglomeration [...]

Wednesday, November 20, 2013

Detailed Animation of Travel Surveys

Despite the amazing potential of new technologies (eg social mediamobile phones) to inform us about spatial patterns in urban mobility, traditional Household Travel Surveys are still a key source of data with preciously detailed information on socio-economic and demographic characteristics.

Recently, Fletcher Foti (Ph.D. student at Berkeley) created a striking detailed animation daily travel patterns using the most recent surveys from the San Francisco Bay Area, Los Angeles, and New York. You may check the animation here and have more information at Emily Badger's post.

ps. If you are interested in travel surveys, you should take a look at the Related Links, below.

[Image Credit: Fletcher Foti, Synthicity]

Thursday, November 14, 2013

Assorted Links

Low-cost interventions on public space

A short presentation by Janette Sadik-Khan (New York transportation comissioner) talking about the recent low-cost interventions on public space in NY. I am keen to read new studies assessing these interventions under different perspectives (urban mobility, housing, segregation, accessibility, real state, market sales etc). I hope there is someone out there doing research on this.

Tuesday, November 12, 2013

Urban Picture

San Francisco after the 1906 earthquake, by George R. Lawrence

Brooklyn Bridge (1913), by Irving Underhill

Online archive with more pictures here. Via Open Culture, great site to visit, regularly!

Sunday, November 10, 2013

Mining bicycle sharing data around the globe

Oliver O’Brien is gradually becoming a great expert on bike-sharing systems. Together with James Cheshire and Michael Batty, Oliver published a paper last month analyzing an impressive amount of data from 38 systems around the globe.


" [...] This paper is the first to take a global view of bike-sharing characteristics by analysing data from 38 systems located in Europe, the Middle East, Asia, Australasia and the Americas. To achieve this, an extensive database depicting the geographical location and bicycle occupancy of each docking station within a particular system has been created over a number of years to chart the usage in the chosen systems (and others) and provide a consistent basis on which to compare and classify them. Analysis of the variation of occupancy rates over time, and comparison across the system’s extent, infers the likely demographics and intentions of user groups. A classification of bike-shares, based on the geographical footprint and diurnal, day-of-week and spatial variations in occupancy rates, is proposed. [...] "
[Image Credit: Oliver O’Brien]

Related Links:

Wednesday, November 6, 2013

Big data and Teenage Sex

Words of wisdom, by Dan Ariely:

[Image Credit: giladlotan on Flickr, via Richard Petry and Cory Doctrow]

The trend of income segregation in the US, 1970-2009

"In 1970, 65 percent of families lived in middle-income neighborhoods; by 2009, only 42 percent of families lived in such neighborhoods".
This is from a report recetly published by Kendra Bischoff and Sean Reardon showing the trend in residential segregation by income in the US between 1970 and 2009. (via Tyler Cowen)

[click on the image to enlarge it]
[Image Credit: Bischoff and Reardon, via Mother Jones]

Monday, November 4, 2013

Bus speeds visualized in real time

As you can see hereAndy Woodruff is a quite talented cartographer! In june this year he released this interactive map where you can visualize (almost in real time) the bus routes and speeds in Boston.
More information at Bostonography blog.

[Image Credit Andy Woodruff]

Related Link:

Quote of the Day

“Anyone who believes in indefinite growth on a physically finite planet is either mad, or an economist.”

Sunday, November 3, 2013

What a million lines of code look like?

[click on the image to enlarge it]

How many lines of code does it take to build an Iphone app, to build Windows 7 operational system, or to operate a Boeing 787?

What a million lines of code look like? What about 500 million lines? You can cilck on the image to check it out (via Information is Beautiful).

[Image Credit: Information is Beautiful]

Tuesday, October 29, 2013

Urban Picture

Would you call this urban sprawl? (via Human Scale Cities, a great blog by the way).
Los Angeles
[Image Credit: ?]


Friday, October 25, 2013

Data Hype, and Vodka

Data analysis/visualization is getting so hype that they are now trying to sell Vodka with it! Congrats to Aaron Koblin.

Thursday, October 24, 2013

If Christaller had Google Earth

Proposed by Walter Christaller in 1933, the 'Central Place Theory' is among the first topics covered by any course in Geography, Regional Science, Urban Studies etc. His main point was to derive the golden rules that would explain the number, location and size (hierarchy) of cities/villages.

To illustrate his proposition, Christaller came up with this classic map showing the distribution of cities and villages in Eastern Europe, where circle indicates population size.

[click on the image to enlarge it]

Sometimes I wonder what those geniuses from the Old Times (like Christaller, Dalí, Paganini) would create if they had the technology we take for granted today. Well, if only Christaller had Google Earth at his time, I'm sure he would have done a much better job. And I think he would have liked to work with Sandra Lach Arlinghaus!

Sandra has done a really nice job overlaping Christaller's map on Google Earth using the exact location (part of what is today Poland). Here you can check her work and download the Google Earth files she's used. It looks much better if you have a big screen.

[Image Credit: Sandra Lach Arlinghaus]

Tuesday, October 22, 2013

Demographic papers published on Science and Nature

It's not everyday you see demographers publishing on journals like Science and Nature. So here is a short list with some of the papers published since 2000.

ps. Massive presence of @IIASAVienna and @WiCVienna researchers!

and my two favorites:

[Image Credit: Lutz and KC, 2011]

Sunday, October 20, 2013

The Flexible City Symposium

This week, I'm attending The Flexible City Symposium, here in Oxford on 24 and 25 of October/2013. The programme looks very good with some great speakers. I would be glad to meet you guys, if you happen to be around the event.

Friday, October 18, 2013

Quote of the Day

"Computers are useless. They can only give you answers." (Pablo Picasso)

Monday, October 14, 2013

Mapping the "Geographies of Time"

Emily Badger points out to this interesting project called Geographies of Time, by Giorgia Lupi and colleagues. The basic idea of the project is to capture the cities pulse using geo-tagged tweets coloured according to the time period of the day they are tweeted.


New York

[Image Credit: UrbanSensing]

Monday, October 7, 2013

Urban Picture

The Radcliffe Camera in Oxford. A nice place to call home!

[Image Credit: Rafael Pereira]


Saturday, October 5, 2013

"The Land of Many Palaces"

In the local mongolian language 'Ordos' means “the land of many palaces". This is the title of a documentary (in production) on one of the famous Ghost Cities in China. It is an independent and low budget film featured by Adam Smith & Song Ting and I wish them luck because this is a great material for a documentary!

[I saw this at Paula Morais' facebook wall]

Tuesday, September 24, 2013

Biographical note: Starting my PhD

Good news!

I’m excited to announce that I'm starting my PhD at Oxford University this Fall. I'll be studying at the School of Geography and the Environment and I'll be probably working on many aspects related to transport inequality (including accessibility, transport policies, land use, spatial segregation, travel behaviour etc) with a bit of demographic perspective here and there.

I look forward to working with the researchers at The Transport Studies Unit (TSU), and particularly with my advisors Prof. David Banister and Tim Schwanen. I'm sure it's going to be a great experience.

You can imagine how excited I am actually, I cant get enough sleep some times. Oxford is a world class university and it had some brilliant 'scientists' such as Adam Smith, Amartya Sen, Thomas Hobbes, John Locke, Stephen Hawking, Edwin Hubble and, of course,  Rowan Atkinson, to name a few.

Some of you may have noticed I've been posting less frequently than usual. Moving from Brazil to the UK is a bit more complicated than I thought. Anyway, I expect to put the blog back on the track in a couple of days.

obs. I am taking a leave from my job at Ipea (Institute for Applied Economic Research) during this period. Hey guys, you know I'll miss you.

I'm moving this week. Wish me luck!

Tuesday, September 17, 2013

The Causes of Informal Housing - EPAINOS 2013 Prize Winner

Every year, the European Regional Science Association (ERSA) gives the EPAINOS award to a young scientist, under 33 years old. It makes me very glad to know that this years’ winner is Daniel da Mata!  Daniel has just finished his PhD in economics at Cambridge University and he is a brilliant researcher we have here at Ipea (Institute for Applied Economic Research).

Here is his awarded paper: "Disentangling the Causes of Informal Housing"

"This article aims to measure the main determinants of the expansion of informal settlements. The focus is on how urban poverty, rural-urban migration and land use regulations impact the growth of slums. I construct a structural model to explain the determinants of informal housing. The model supports the main empirical evidence regarding slums formation and it is able to quantitatively assess the role of each determinant of slums growth. The model is calibrated and estimated to be consistent with several statistics related to the Brazilian urbanization process from 1980 to 2010. I present several counterfactual experiments to assess the role of income, migration and land use regulation. The results show that these factors explain about half of the variation in slums growth between 1980 and 2010. I also perform ex-ante evaluation of the impacts of slum upgrading interventions and show how policies may have unintended adverse effects on slums formation."

By the way: Guilherme Resende was awarded the EPAINOS prize in 2009. Guilherme is another great researcher at Ipea.

Friday, September 13, 2013

Urban Picture

An invisible frontier in Nouakchott, Capital of Mauritania

[Photography: Steve McCurry National Geographic August 1987
invisible frontier, via Human Scale Cities]

Related Links: