A control system based on chaos has made a simulated, multi-legged robot walk successfully. The researchers behind the feat say it may have brought us closer to understanding how people and animals learn to move.

Standard robots control their leg motion either through complex computer programs or by using so-called genetic algorithms to “evolve” a successful walking strategy. Both these options are time-consuming and require a lot of computer power.

Roboticists Yasuo Kuniyoshi and Shinsuke Suzuki wondered whether chaotic systems might also generate efficient walking behaviour. Chaotic systems behave in a way that means that small effects are amplified so rapidly that the systems’ behaviour becomes impossible to predict more than a short time ahead. Such chaotic systems are behind a number of phenomena, including the weather and the performance of financial markets.

Researchers need enormous computer power to forecast changes in the Earth's climate, but they can predict the speed of a ball rolling down a ramp with pencil and paper. Stephen Wolfram claimed in his 2002 best seller, A New Kind of Science, that there is a clear dividing line between complex problems that require computer crunching and those for which equations alone will do. He argued that many important problems are more like the climate than the ball. But according to the 20 February PRL, his definition of complexity is imperfect because many of the problems he classified as complex are easily solved, as long as you can accept approximate answers. The results suggest that the traditional approach of physics--the equivalent of pencil and paper--is more widely applicable than Wolfram's analysis implies.

Sync: The Emerging Science of Spontaneous Order
Steven Strogatz
Copyright 2003

Encryption schemes that hide messages in chaotic signals have attracted attention in recent years as a means to transmit information securely but most work has been either theoretical or strictly limited to laboratory experiments. Now a group of researchers in Beijing have managed to demonstrate chaotically encrypted, two-way voice transmission through the Beijing Normal University computer network.

Nature always tends to act in the simplest way.
- Bernoulli

Bak, Tang and Wiesenfeld developed the concept of "self-organized criticality" in 1987 while studying the theoretical behaviour of a sand pile, in which grains of sand are sprinkled onto the pile, one at a time. As the pile grows, its sides become steeper, eventually reaching a critical state when just one more grain would trigger an avalanche.

Bak and his co-workers realised that it was impossible to predict if a particular grain would cause an avalanche. The size of these avalanches is, however, distributed according to a "power law", and they coined the phrase "self-organized criticality" to describe the pile's natural growth to a critical state. Their work showed that many phenomena in Nature are so complicated that their large-scale behaviour cannot be predicted from their microscopic origin. Self-organized criticality has since been applied to many other natural systems, including the size of earthquakes, the spreading of forest fires, the fluctuations of stock-market prices, and X-rays emitted by solar flares.

When BTexact Technologies, BT�s advanced communication technologies business, QinetiQ, one of Europe�s largest science and technology solutions providers and the Ministry of Defence, set out to collaborate in making the most effective possible use of limited radio spectrum for the next generation in battlefield communications technology, their first step was to take inspiration from the natural world...

...Mimicking the flies� own organisational attributes, the algorithm would allow base-stations in a mobile phone network to negotiate with each other and decide how the available radio frequencies will be divided up to meet the demand for calls without causing unacceptable interference. It would even �heal� in the event of a base-station failure, totally negating the need for a central organiser to track events in the network and re-plan frequency use to accommodate faults and changes in demand.

Mathematicians have achieved a major step towards answering the question of whether numbers like pi and other mathematical constants are truly random and for the first time linked number theory with chaos theory.
It is not just a mathematical curiosity they say. Proving that pi never repeats itself would be a major advance in our theory of numbers.

It may also allow the construction of unbreakable codes based on long sequences of random numbers.

A New Kind of Science
Copyright 2002
By Stephen Wolfram
A New Kind of Science, raised expectations that some great new understanding was about to be shared with the world, but now here it is, and many are disappointed. It's an impressive work, with roughly a thousand high quality images, but the author's incredible ego, and overly wordy style get in the way of readability. Written during ten years in isolation and without feedback from the scientific community, the book suffers from lack of acknowledgement of the work of others, and questionable accuracy in some areas.

A mysterious disturbance in the forces at the heart of the Solar System could have triggered the asteroid that wiped out the dinosaurs.

This intriguing new theory has been put forward by scientists who have calculated the paths of the planets over the past 100 million years.

A US team believes a change in the dynamics of the Solar System caused Mercury, the Earth and Mars to veer off course.

This could have pushed a giant asteroid towards our planet, spelling downfall for most living things, 65 million years ago.

Investigations
By Stuart A. Kauffman
Copyright 2000

Reason’s last step is the recognition that there are an infinite number of things which are beyond it.
- Blaise Pascal

I say unto you; one must still have chaos in oneself to be able to give birth to a dancing star.
- Nietzsche

The Origins of Order: Self-Organization and Selection in Evolution
By Stuart A. Kauffman
Copyright 1993