Showing posts from 2009

Mexico 2010

2010 seems to be a promising year. Here in Mexico, we will celebrate 200 years of the beginning of the Independence (September 16th, 1810) and 100 years of the beginning of the Revolution (November 20th, 1910). By linear extrapolation, we all expect a great event to occur in 2010. But there are different opinions on what precisely will occur.The hope of the people: winning the World Cup. The fear of the people: collapse of the country. The most possible outcome: financial difficulties of historic proportions.
The Guajiran dream: the refoundation of the Republic (it has been going down the drain for too long). My personal bet/conspiracy theory: druglords taking over the country followed by a foreign invasion rescue operation.

New Book Chapter draft: Self-organizing urban transportation systems

Self-organizing urban transportation systemsCarlos Gershenson. To be published in "Complexity theories of cities have come of age", edited by Juval Portugali and Han Meyer (Springer, 2010).
Abstract: Urban transportation is a complex phenomenon. Since many agents are constantly interacting in parallel, it is difficult to predict the future state of a transportation system. Because of this, optimization techniques tend to give obsolete solutions, as the problem changes before it can be optimized. An alternative lies in seeking adaptive solutions. This adaptation can be achieved with self-organization. In a self-organizing transportation system, the elements of the system follow local rules to achieve a global solution. Like this, when the problem changes the system can adapt by itself to the new configuration. In this chapter, I will review recent, current, and future work on self-organizing transportation systems. Self-organizing traffic lights have proven to improve traffic …


Folks at Indiana University have developed Tenurometer, a Firefox plugin to analyze different metrics of academic productivity. Researchers from all areas, take a look! The more people use it, the more useful it will be.

Artificial Life courses around the world

As a part of a new ALife workgroup, Tom Barbalet is putting together a list of ALife-related courses around the world. Quite an interesting exercise...

Paper Published: Why Does Public Transport Not Arrive on Time? The Pervasiveness of Equal Headway Instability

Gershenson C, Pineda LA (2009) Why Does Public Transport Not Arrive on Time? The Pervasiveness of Equal Headway Instability. PLoS ONE4(10): e7292. doi:10.1371/journal.pone.0007292
AbstractBackgroundThe equal headway instability phenomenon is pervasive in public transport systems. This instability is characterized by an aggregation of vehicles that causes inefficient service. While equal headway instability is common, it has not been studied independently of a particular scenario. However, the phenomenon is apparent in many transport systems and can be modeled and rectified in abstraction.MethodologyWe present a multi-agent simulation where a default method with no restrictions always leads to unstable headways. We discuss two methods that attempt to achieve equal headways, called minimum and maximum. Since one parameter of the methods depends on the passenger density, adaptive versions—where the relevant parameter is adjusted automatically—are also put forward. Our results show that th…

Fractal Projections:Tetrahedra

Fractal Projections:Tetrahedra by ~hawmkoonstormbringer on deviantART

I was a few weeks ago in Budapest for a conference on artificial life. I went to the Vasarely museum, and I liked a lot his perspective games, e.g. a sphere projected on a plane and cubes projected on the sphere. I thought that you could do this recursively, so you can project tetrahedra on the faces of tetrahedra, and this is the result...

This work is dedicated to the 30th birthday of my hopeful wife Nadya...

Google Scholar Metrics?

I wonder why Google Scholar has not implemented some metrics of scientific productivity equivalent to the popular ISI impact factor, which is used by most institutions and funding agencies to measure the qualifications of researchers. There are many problems with the impact factor, one of them being that it covers about 10% of published work. Google Scholar has a much broader database (although some of it needs polishing, since data was harvested automatically), and it would be great if they could implement at least some of these 39 measures. Well, scHolar index already does some...

New Swimming World Records: Technology or Training?

Yesterday was the final day of the World Swimming Championships in Rome. In the 40 swimming events, there were 43 new world records (Records were not set in every event, but in some events they were set several times between prelims, semifinals and finals). This is amazing and unprecedented.

Many give credit to the new technology of swimsuits, which give swimmers a greater buoyancy. For this reason FINA is banning these swimsuits from next year, arguing that the swimsuits are helping swimmers as swimming enhancing technology. Some even say that the swimsuits are making a mockery of the sport, being it so easy to break a world record. In one of the finals, a swimmer made a time under the old world record, but was fifth place...

Well, let us note that some swimmers, e.g. Phelps, Lochte, Peirsol, were not using the latest technology in swimsuits, and nevertheless they broke world records. It is not only the swimsuits.

Also, should the swimsuits be really banned? It is a complicated questio…

Book Review: Reinventing the Sacred, by Stuart A. Kauffman.

Gershenson, C. (2009). Book Review: "Reinventing the Sacred: A New View of Science, Reason, and Religion". Stuart A. Kauffman.Artificial Life15(4):485-487
Excerpts: One of the main goals of this book is to demonstrate the inadequacy of reductionism in contemporary science. It does not negate its explanatory and predictive powers. It notes its limits, exploring several phenomena that are not predictable due to their complex nature. Thus, Kauffman argues, a shift in science is required if we want to understand these complex phenomena.

People might disagree with the answers that Kauffman puts forward. However, in my opinion the greatest contribution of this book, as with Plato╩╝s works, lies in the questions asked. It points out clearly which problems are currently relevant for science and society, even those that people are not aware of. Different tentative or partial solutions can be debated. However, the most difficult part is to start the discussion, and that is precisel…

New paper: Modeling self-organizing traffic lights with elementary cellular automata

Carlos Gershenson and David A. Rosenblueth, "Modeling self-organizing traffic lights with elementary cellular automata", C3 Report No. 2009.06.Abstract: There have been several highway traffic models proposed based on cellular automata. The simplest one is elementary cellular automaton rule 184. We extend this model to city traffic with cellular automata coupled at intersections using only rules 184, 252, and 136. The simplicity of the model offers a clear understanding of the main properties of city traffic and its phase transitions.We use the proposed model to compare two methods for coordinating traffic lights: a green-wave method that tries to optimize phases according to expected flows and a self-organizing method that adapts to the current traffic conditions. The self-organizing method delivers considerable improvements over the green-wave method. For low densities, the self-organizing method promotes the formation and coordination of platoons that flow freely in four …

New Draft: What Does Artificial Life Tell Us About Death?

I just uploaded to the arXiv a first draft of a short essay "What Does Artificial Life Tell Us About Death?", you can download it at:

Why Do Developing Countries Not Develop

After several years living abroad (St. Petersburg, Sussex, Brussels, Granada, Boston), it takes a bit of time to get used to life back in Mexico City.

Having some frame of comparison, I realized one way to describe the problem with developing countries such as Mexico: there is a high degree of incompetence.

Now, it is difficult to measure incompetence (In TeraBushes?), but to understand better what I mean, let us say that an agent (person, business, organization) is more incompetent if there are more tasks that the agent should perform successfully and it does not. I mean, I am quite incompetent in bureaucratic monotonous tedious labours, but these are not my duty (which some people refer to as "professional handwaving", others as "academia").

All countries and all agents have a certain degree of incompetence: nobody is perfect, there will always be errors, especially with novel tasks. Also, all countries and agents have a large degree of functionality, things that do…

Tentative Research Projects

I made a list of potential research projects I would like to explore with colleagues and/or students. You can find it here.

New Paper: Enfrentando a la Complejidad: Predecir vs. Adaptar

Resumen: Una de las presuposiciones de la ciencia desde los tiempos de Galileo, Newton y Laplace ha sido la previsibilidad del mundo. Esta idea ha influido en los modelos cientificos y tecnologicos. Sin embargo, en las ultimas decadas, el caos y la complejidad han mostrado que no todos los fenomenos son previsibles, aun siendo estos deterministas. Si el espacio de un problema es previsible, podemos en teoria encontrar una solucion por optimizacion. No obstante, si el espacio de un problema no es previsible, o cambia mas rapido de lo que podemos optimizarlo, la optimizacion probablemente nos dara una solucion obsoleta. Esto sucede con frecuencia cuando la solucion inmediata afecta el espacio del problema mismo. Una alternativa se encuentra en la adaptacion. Si dotamos a un sistema de esta propiedad, este mismo podra encontrar nuevas soluciones para situaciones no previstas.

Abstract: One of the assumptions of science since the times of Galileo, Newton, and Laplace has been the predictab…

Webpage update

I finally was able to update my webpage. Its new location is

WolframAlpha: The next big Web breakthrough?

When Google was released, it revolutionized the quality of search engines, transforming the world society: it enabled anyone with Internet access to find almost any information. Knowledge available to everyone.

The next big technology to have a global effect might be WolframAlpha, to be released in a few weeks. Its main goal is in line with the main vision of the Internet: to make expert-level knowledge accessible to anyone. It is complementary to search engines, which find data. WolframAlpha computes structured data.

I just listened to a preview webinar by Stephen Wolfram, the leader of the project where already several hundred people are working. In exploits the computational capabilities of Mathematica, huge databases and live feeds of structured data, an impressive free form linguistic analysis, and an automated presentation of relevant results.

It does much more than mathematics (from sums to integrals) It can calculate interesting comparisons, e.g. GDP of countries, weather of citi…

CfP: Swarm Cognition Workshop

Call for Papers: Swarm Cognition Workshop

The workshop is part of the 31st Annual Meeting of the Cognitive Science Society (CogSci 2009 - )


Swarm Cognition" is the juxtaposition of two relatively unrelated concepts that evoke, on the one hand, the power of collective behaviours displayed by natural swarms, and on the other hand the complexity of cognitive processes in the vertebrate brain. With this premise, the Swarm Cognition Workshop aims at promoting synergies between diverse disciplines such as cognitive neurosciences, psychology, ethology and swarm intelligence. Research work in Swarm Cognition aims at identifying the operational principles of cognitive behaviour by calling upon the underlying mechanisms of self-organising systems, i.e., sys…

Recursive Yin Yang 4

Recursive Yin Yang 4 by ~hawmkoonstormbringer on deviantART

The basic construction of a yin-yang symbol is to take a circle and two circles of half the radius, sitting along one axis. I used this substitution recursively with a 90 deg. rotation: For the smaller circles, add two more circles of half their radius (one fourth of the original circle). Continue substituting, and you end up with this figure. The interesting thing is that not only the surfaces are fractal, but also the line separating the two colors.

The figure can carry several messages, apart from those of yin yang: e.g. there is also struggle, balance, and interaction at different scales.

This work is dedicated to our friend and compadre Dr. Igor Lugo, who recently defended his PhD.

Tentative Laws of Information

All phenomena can be described as information, so these laws try to describe general features found across all scales.
Law of Information Transformation. Information will potentially be transformed by interacting with other information.Law of Information Propagation. Information propagates as fast as possible.Law of Requisite Complexity. More complex information will require more complex agents to perceive, act on, and propagate it.Law of Information Criticality. Transforming and propagating information will tend to a critical balance between its stability and its variability.Law of Information Organization. Information produces constraints that regulate information production.
These tentative laws are generalizations of Darwinian, cybernetic, thermodynamic, and complexity principles.

More details and examples in:
Gershenson, C. (2007). The World as Evolving Information. In Proceedings of International Conference on Complex Systems ICCS2007.

Complexity Digest

Gottfried Mayer died last January 25th, after more than a year of fighting with cancer. I've taken his position as editor of Complexity Digest. I will try to keep up the standards that Gottfried set. We will miss him.