Economist just posts an interactive visualization Chinese Equivalents on their website. It’s a very interesting approach. (Somehow I feel it has an psychological side-effect by saying one province is equivalent to France while it’s neighbor is equivalent to Kenya, though noted in terms of population.)

I got curious how we can visualize how actually important the Chinese provinces are. I was reading Gastner & Newman’s paper Diffusion-based method for producing density-equalizing maps (PNAS 2004) at the time. So I set out to make my first density-equalizing map.

Newman’s code on his website deals with raster image only. I also tried to implement a diffusion simulator in Processing, but it was hard to preserve all the details of a vector map. Below is my first shot. It took (quite) some manual effort to remove the bad points. Still seeking solutions. Anyway, enjoy.

You can recognize in this map how unbalanced China is – the west is barely occupied due to challenging natural environment, and population keeps flowing from the middle towards the economic centers (Beijing and the southeast coast). They become both productivity and pressure for big cities.

What about looking at the provinces from a social network’s perspective? In the following graph I measured how often each two provinces appear in the same media coverage. It is clear now that Beijing is the absolute, mono-center of all China. The social power is not proportional to a province’s population. The south and the east coast get far more attention than inland provinces, which is a sad fact.

Tools used: Processing, Tulip, Illustrator

This is my final project for 6.849: Geometric Folding Algorithms by Prof. Erik Demaine, the happiest genius of the world.

In fact I prefer to call it ‘the origami class’, which sounds more obscure to my friends. And complex, curving origami was indeed what I expected myself to do at the beginning. Well, the field turned out to be much broader and even more interesting (absolutely an understatement).

Anyway one day we were introduced to Kemp’s Universality Theorem, which says ‘there is a linkage that signs your name’. In proving that Kemp invented 3 gadgets: multiplicator, additor and translator, which perform arithmetic operations on any input angle. Then the idea came to me that if we can design gadgets that perform boolean operations, we can build a computer from just hinged bars.

I always had a thing for mechanical computers. The article that talks about the rope-and-pulley computer by Apraphulians was my all-time favorite of Scientific Americans. This project might be a little nerdy, but who knows — mechanical logic gates do make sense on nanoscale and in extreme environments like outer space.

Here is how I represent bits with bars. Note that each bar is constrained to rotate in half plane so I gain a nice ‘black box’ feature where the implementation of one gadget does not disrupt the rest of the machine.

Here are the logic gates: translator (moving a logic state across space), invertor (X -> not X), AND gate / OR gate (they are mirrored image of each other). Watch the video to see how they work.

Download Video: MP4
HTML5 Video Player by VideoJS

Using the above gadgets I will be able to build a full adder (A, B, Cin as input and S, Cout as output). I’ve made a simple simulation with Processing. Click the input bars to switch states:

The models I constructed use wood sticks and rivets. I also proposed another way of building the gadgets — cut and fold them from one piece of flat material. It would be awesome to cut a whole mechanical computer out of one piece of thin metal, roll it and take it with you to a place with no electricity and do some crazy computation.

I’ll be continuing this project during the winter break. Many thanks to Erik & Martin Demaine and Tomohiro Tachi. It’s been so cool!

Tools used: AutoCAD, Processing

This paper has been published on PLoS ONE: full text

Do regional boundaries defined by governments respect the natural way that people interact across space? The URB team of SENSEable City Lab analyzed 12 billion anonymized landline calls in Great Britain to illustrate the true connections between places. The strength of connection is defined by the frequency and period of phone calls. It is revealed that people tend to communicate with those that are geographically close to them. Therefore, it is possible to identify clusters of connections as regional groups. It is fun to compare these new boundaries with existing ones and see how much people really love each other.

The visualization challenge here is the extra dense connections. An ideal vis solution should show clearer and finer pattern as data accumulates, not the opposite. Mauro Martino worked with the team from the beginning and derived the primary concept. I hopped on board later and finished with the final video to elaborate the whole idea. Processing is not able to handle this scale of objects (especially in animation) so a lot of pre-processing was done exclusively for each scene.

For those who cannot use YouTube, click this instead:

Download Video: MP4
HTML5 Video Player by VideoJS

The research has also been covered by BBC and The Economist.

Uh… This is purely out of boredom. In welcome of the Season 6 of CW show Supernatural, I took a look at the path Sam and Dean have traveled. Guess which state hosted the most monsters?

Congratulations to Illinois! Then there goes South Dakota, Nebraska, Kansas, Pennsylvania, Ohio, Iowa, Indiana, Colorado, Missouri, Wisconsin, Oklahoma, Minnesota and California. The supernatural communities, be them spirits, creatures, mutants, psychics, witches, demons, angels or gods, definitely share taste in choosing playgrounds.

This is a project for a Media Lab class: New Paradigms for Human-Computer Interaction by Pattie Maes and Hiroshi Ishii. Slow glass was imagined by Bob Shaw in the science-fiction story The Light of other Days. Light travels very slowly in this material so that it takes months or even years for people to see what had been on the other side.

We consider the slow glass as an architectural element that provides a window into another space/time. It changes people’s perception of the surroundings. We tried to make an elegant implementation for the concept. The screen is located in the lobby of the new Media Lab building. One camera captures sequential images of the lobby and tracks the coordinates of people using background subtraction. Another set of cameras on the back of the screen records a panorama of the lobby. Video is played back, a few hours later, according to the relative positioning between a person and the screen. From a user’s perspective, the screen is like transparent, only that through it he sees the past.

The tracking system, powered by OpenCV:

A diagram of perspective simulation:

A video of the concept and the first prototype that we presented in the class review. We are currently working on making it a permanent installation in the Media Lab building:

Download Video: MP4
HTML5 Video Player by VideoJS

Tools used: Open Frameworks, OpenCV, iMovie
Collaborator: Polychronis Ypodimatopoulos, Daniel Rosenburg