Www.er.ethz.ch/WSJ_article. FX HORIZONS: Move Over Economists; Time to Give Physicists a Turn - MoneyBeat. FX HORIZONS: Move Over Economists; Time to Give Physicists a Turn - MoneyBeat. Didier Sornette: How we can predict the next financial crisis. Scientific Data Has Become So Complex, We Have to Invent New Math to Deal With It - Wired Science. Simon DeDeo, a research fellow in applied mathematics and complex systems at the Santa Fe Institute, had a problem.
He was collaborating on a new project analyzing 300 years’ worth of data from the archives of London’s Old Bailey, the central criminal court of England and Wales. Granted, there was clean data in the usual straightforward Excel spreadsheet format, including such variables as indictment, verdict, and sentence for each case. But there were also full court transcripts, containing some 10 million words recorded during just under 200,000 trials.
“How the hell do you analyze that data?” DeDeo wondered. “In physics, you typically have one kind of data and you know the system really well,” said DeDeo. DeDeo is not the only researcher grappling with these challenges. Gunnar Carlsson, a mathematician at Stanford University, uses topological data analysis to find structure in complex, unstructured data sets. Today’s big data is noisy, unstructured, and dynamic rather than static. How Dragon Kings Could Trump Black Swans. The study of power laws has become a significant part of modern science.
Power laws, it seems, are ubiquitous in the way they describe size distribution of everything from earthquakes to forest fires to financial crashes. But there’s a curious phenomenon associated with power laws that statisticians until now have missed, says Didier Sornette at the Swiss Federal Institute of Technology. And this provides an interesting new way to look at extreme events. Let’s look at what he’s claiming. Sornette gives as an example the distribution of city sizes in France, which follows a classic power law, meaning that there are many small cities and only a few large ones. Paris is an outlier because it has been hugely influential in the history of France and so has benefited from various positive feedback mechanisms that have ensured its outsize growth. So what to make of this?
That’s important. But Sornette goes further. That’s much more speculative. Using Chaos Theory to Predict and Prevent Catastrophic 'Dragon King' Events - Wired Science. A strange attractor plotting the behavior of a chaotic system.
New research suggests that some chaotic systems could contain particular variables that can predict and stop extreme events from occurring. Image: Nicolas Desprez/Wikimedia Stop a stock trade and avoid a catastrophic global financial crash. Seal a microscopic crack and prevent a rocket explosion. Push a button to avert a citywide blackout. Though such situations are mostly fantasies, a new analysis suggests that certain types of extreme events occurring in complex systems – known as dragon king events – can be predicted and prevented.
“A chaotic system may be in flux, and look like random behavior,” said physicist Daniel Gauthier of Duke University, co-author of a paper appearing Oct. 30 in Physical Review Letters. By looking at a simple experimental chaotic system, Gauthier and his co-authors have been able to detect telltale signs that a dragon king event was approaching and, most importantly, stop it from happening. ETH - Entrepreneurial Risks - Entrepreneurial Risks. La quête des rois dragons. Par Rémi Sussan le 19/11/13 | 12 commentaires | 1,271 lectures | Impression La prédiction est un art difficile, surtout lorsqu’il s’agit de l’avenir, dit le dicton.
De fait, nous nous trouvons aujourd’hui à devoir comprendre et gérer des phénomènes appartenant à la catégorie des systèmes complexes, autrement dit impliquant un grand nombre d’acteurs et d’interactions, qui échappent largement à la prévision. Pourtant, les tentatives pour circonvenir le problème ne manquent pas. Il existe plusieurs moyens de traquer les systèmes complexes : on peut utiliser les automates cellulaires, la cybernétique, les systèmes multi-agents. Cette fois, nous apprend Wired, un groupe de mathématiciens aurait trouvé un moyen de prédire, et éventuellement d’empêcher, la survenue d’évènements qu’ils appellent les “rois dragons”.
Le terme “roi dragon”, nous explique la revue, viendrait de la distribution des richesses dans la société médiévale. Du cygne noir au Roi Dragon Se méfier des bulles Et le futur ?