3D Biomorphs

As some of you may probably know, I am very interested in Biomorphs since the design of the Lifedrop virtual ecosystem (see the LifeDrop page on the right). In LifeDrop, the virtual water drop is like a 3D sphere with simple physical simulation. Biomorphs are true autonomous agents and their 3D shapes are based on the original Richard Dawkins recursive procedure simply called Tree in the Blind Watchmaker program. Concerning the 3D rendering, I have just made a small adaption to this original 2D routine in order to have some "legs" in 3D. However, I am not very satisfied by this approach. I would be very interested if someone has already found a better way for drawing 3D Biomorphs. The problem is that procedure not only needs to show the same properties as in 2D, but also a much better rendering. As an example of a better rendering in 2D, the image shows "Mandelbrotset Biomorph" which has been computed using Mathematica (see http://www.bugman123.com/Fractals/Fractals.html for details). However, since LifeDrop runs multiple Biomorphs agents in parallel, the drawing procedure must be optimized to obtain fast rendering. All theses points make the problem hard to solve. However, I think it is possible and when this point will be resolved, I will update LifeDrop.

Les indispensables

Une fois n'est pas coutume, un post en français car le sujet s’y prête. Il s’agit d’un coup de projecteur sur le livre d’Alexandre Moatti édité par Odile Jacob : Les indispensables – Mathématiques et Physiques pour tous. Un excellent livre de culture générale scientifique qui a le mérite de couvrir effectivement " les indispensables " : nombre d’or, nombres parfaits et amicaux, quadrature du cercle et courbes fractales, vitesse de la lumière et trous noirs, théorème de Gödel et relation d’incertitude, relativité et théorie du chaos. Même dans le domaine relativement pointu des créatures artificielles, et a fortiori pour tous ceux qui s’intéressent aux sciences de la complexité, la lecture rafraîchissante de ce livre apportera une perspective intéressante : il est possible en effet de présenter des concepts et des théories jugés souvent " trop compliqués " de façon simple et compréhensible, sans introduire un décalage entre le scientifique et l’honnête homme du XXIe siècle.

Daedalus and Artifical Creatures

This is a photo of the Knossos's palace taken last week during my vacation in Crete : in greek mythology, this is the famous "Labyrinth" which was an elaborate maze constructed by King Minos of Crete and designed by Daedalus to hold the Minotaur, a man-eating monster that was half man and half bull. Daedalus is an important figure in the history of artificial creatures. He was a great architect and sculptor who's said to have created wooden "moving statues" and many other artifacts : he has built for Minos' wife, Pasiphae, a wooden cow so she could mate with the Minotaur ; he has fabricated wings for himself and his young son Icarus to escape from Crete, but Icarus flew too near the sun and fell into the sea. It is very difficult to know if Daedalus, like Minos itself, have really existed or if it is only a myth like many others in the antic greek legendary tales. However, the fact is that the palace exists and has been dated around 1700 B.C. (bronze age period) that is over 3500 years old.

Eonomic Instability

In this post, I want to focus on a very interesting paper published by Y. Louzoun et. al. in 2003 (Artificial Life vol. 9 n. 4 - MIT Press). Their paper shows that world-size global market lead to economic instability. The model is based on an extended Lokta-Voltera equation applied on a two-dimensional lattice with two main parameters: R is the range over which competition between agents can take place, and D is a diffusion coefficient of wealth. They argue that extreme values for globalization R and redistribution D, as advocated respectively by extreme capitalism and extreme socialism, are equally counterproductive and possibly disastrous due to catastrophic fluctuations. However, there is a regional globalization scale that seems to optimize the system. They conclude that moderate-size regional markets (R ~ system size / 10) partially protected from external competition, are the optimal economic configuration. Well, I would like to have enough time to be able to work on that subject. Interesting, no ? (Earth image from space - Courtesy Nasa).

Al-Jazari Automata

Yesterday, I have visited the "The Golden Age of Arabic Sciences" exhibition at the Arabic World Institute in Paris. Among a very good selection of many scientific discoveries of this civilisation, it was an opportunity to see some documents written by Al-Jazari. Ibn Ismail Ibn al-Razzaz Al-Jazari (1206 AD) was one of history's greatest engineers. He invented many automata and some of the first mechanical clocks, driven by water and weights. He was called Al-Jazari after the area where he was born, Al-Jazira, which is the traditional Arabic name for northern Mesopotamia. Al-Jazari draws on the works of its predecessors both from the Greeks (Philon, Heron and Archimede) and Islamic world (Banu Musa brothers, Al-Khuwarizmi and Ridwan). His contribution was very important for the diffusion of knowledge in the Arabic world and after in Europe due to the translations of his books like "The Book of Knowledge of Ingenious Mechanical Devices" which contains more than 150 automata and mechanical devices. I take the picture in the museum showing a page of "A Compendium on the Theory and Practice of the Mechanical Arts" dated 1315-1316 (AD). The picture shows the internal structure of an automata for serving and arbitrating drinking sessions. That is to say that Al-jazira has an important place in the history of artificial creatures.

Digital Life and Evolution

In the famous Science-Fiction Hyperion book series written by Dan Simmons, the evolution of small virus programs in the Internet leads to the Infosphere. The story begins with Tom Ray’s Tierra project and ends with Artificial Intelligences, cybrids, and other virtual creatures. Is that possible ?
There is a long story of virtual ecosystems research projects : Tierra, Avida, LifeDrop and many others (left image shows a typical LifeDrop run - you can experiment it by following the LifeDrop link on the right). All these programs are based on the evolution of digital organisms by means of “digital DNA” mutations and cross-overs. Another characteristic is that these programs use a virtual machine layer between the computer operating system and the creatures. This virtual machine creates a more suitable environment for bio-inspired digital creatures and it represents also a sort of protection barrier between the system and the outside computer world. After more than a decade of research, some digital organisms are getting closer to fulfilling the definition of biological life : most of the features that biologists have said were necessary for life we can check off. These experiments raise multiple questions: What is the definition of life ? Are some of these digital creatures really alive ? Is the evolution in such systems really open-ended ? Is it possible to create digital organisms directly in the computer memory without any ecosystem simulation ? Well, I’ll try to address some of these important questions in future posts… Keep tuned.

Modeling Stock Markets with Cellular Automata

In the recent years, there has been an increasing interest in simulating financial systems using multi-agent models and Cellular Automata (CA). There is a strong feeling that financial markets are typical complex systems in which the global dynamical properties mainly depend on the evolution of a large number of non-linear interacting agents. An extreme view of this is to consider that much of the randomness of financial markets is the consequence of their dynamics and has little to do with the nature or value what is being trade. This is in contrast with classical models that assume that investors are rational and consider the price a random walk. In his book "A New Kind of Science", Stephen Wolfram has proposed a very simple and idealized model of a stock market. It is a one-dimensional CA where each cell corresponds to an entity that either buys or sells on each step. The behavior of a given cell is determined by the one of its two neighbors at the preceding step (see diagrams (C) S. Wolfram). The application on this rule results in a sort of random behavior that look likes those seen on stock markets curves.

This is true but the problem is that this model is so simple, not to say trivial, that we can use it to model almost everything. Well, I am probably too severe here, but we need a more realistic CA model to work on financial markets. I have tried to use a two-dimensional CA with three states: sell, keep or buy, and a more realistic transition rule. However, at this time, results are not very convincing from my point of view. The colored picture is a small part of a bigger image showing a typical run. One important feature of this model is the deterministic nature of its transition rule that contrast with most other studied stock market CA models. So, I hope to find something interesting the near future.