I've been only twice to Copenhagen, but I really liked it there. That's of course because the Danish people are very nice, but also because I really like how the city feels.
There's a great TEDtalk on architecture by some Danish with focus on sustainability: Link to TED page.
I strongly suggest to not watch the video in the embedded video frame size!
Samstag, 28. Januar 2012
Freitag, 27. Januar 2012
Market Makers & Prediction Markets
A while ago I posted on the idea of futarchy and followed up with a post on implementation and issues of virtual stock markets.
I only posted links on auction markets, i.e. where one party makes an offer, another one a request and the system finds a match. That only works good for systems with high liquidity. Especially on prediction markets with combinatorical outcomes (e.g. of the form "if person A becomes the candidate for party 1, then party 2 will win the election" or even more complex constructions) this is difficult: you need to find people making similar opposite bets to match. A way around of this is to use a market maker instead of an auctioneer. It takes the trades directly instead of leading a negotiation between to parties. The price is set automatically by the system. This, of course, also has drawbacks. In a real life system, the market maker provides liquidity and thus is at risk losing some money. Moreover, the pricing of the goods depends on parameters of the market maker. Wrong values for thick or thin (i.e. markets with many/few participants) might make the price either bounce up and down or move only tiny bits.
I only posted links on auction markets, i.e. where one party makes an offer, another one a request and the system finds a match. That only works good for systems with high liquidity. Especially on prediction markets with combinatorical outcomes (e.g. of the form "if person A becomes the candidate for party 1, then party 2 will win the election" or even more complex constructions) this is difficult: you need to find people making similar opposite bets to match. A way around of this is to use a market maker instead of an auctioneer. It takes the trades directly instead of leading a negotiation between to parties. The price is set automatically by the system. This, of course, also has drawbacks. In a real life system, the market maker provides liquidity and thus is at risk losing some money. Moreover, the pricing of the goods depends on parameters of the market maker. Wrong values for thick or thin (i.e. markets with many/few participants) might make the price either bounce up and down or move only tiny bits.
Samstag, 7. Januar 2012
Uncertainity Principle(s)
Most people know a formulation of the uncertainity principle in quantum mechanics (by Heisenberg), where it basically gives a bound (in terms of the standard deviations of ~) for simultaneous measurements of complementary properties (i.e. measurement operators with non-negative commutator).
There are a number of other places where the principce turns up. It comes from an application of the cauchy schwarz inequality to the fourier transformation. Here's a set of (german) slides from a lecture. Recently Terry Tao posted on a a formulation of the principle due to Mongomery, which has applications in analytic number theory.
There are a number of other places where the principce turns up. It comes from an application of the cauchy schwarz inequality to the fourier transformation. Here's a set of (german) slides from a lecture. Recently Terry Tao posted on a a formulation of the principle due to Mongomery, which has applications in analytic number theory.
Dienstag, 3. Januar 2012
On Human Brain Size; the Conciousness and Anaesthesia
A happy new year to all readers. I just got two articles with some references on further resources:
In near future, I will post some more math; I just haven't read all the things I stumbled on.
edit: let me squeeze in another link to an article:
Language learning is fast when words are connected with movements/gestures, which is also true for abstract words with no obvious gesture for it.
In near future, I will post some more math; I just haven't read all the things I stumbled on.
edit: let me squeeze in another link to an article:
Language learning is fast when words are connected with movements/gestures, which is also true for abstract words with no obvious gesture for it.
Samstag, 24. Dezember 2011
On (implementation issues of) Virtual Stock Markets
After my recent post on prediction markets, I decided to implement a small auctioneer for virtual stock markets with two parties making deals, i.e. not a market maker mechanism but a (traditional) double auction. But, despite the simple idea behind a bid/ask driven market, the implementation has to take into account quite a number of details: can you buy/sell one unit or multiple units of a good at a time? Does trading occur at discrete events or is it continuous? Is pricing uniform (all trade at the same equilibirum price) or discriminatory (individual matching of bid/ask orders)? And, if one the two options is chosen, how is the price determined?
- Beside the double auction system, bidding can take other forms: Auctions and Bidding: A Guide for Computer Scientists
- Everything you wanted to know about double auctions, but were afraid to (bid or) ask
- And finally a paper on two multi unit k-double auction algorithms
Donnerstag, 22. Dezember 2011
Reading Speed: Chinese vs English
I always wondered about mankind's languages and writing systems, one of the reasons I looked into Lojban (quite) a while ago. In an earlier post about writing systems I expressed my fascination about non-linear systems. But even with linear systems, we have alphabetic, syllabic and logographic systems. But it turns out the our systems are optimal in the sense that our cognitive abilities won't let us process more optimized systems, at least that is indicated by a study on reading speed with Chinese vs English - two major examples of logographic and alphabetic writing systems.
Mittwoch, 14. Dezember 2011
Futarchy: applying prediction markets
R. Hanson suggests to use prediction markets to make better use of information to evaluate strategies in politics. He calls the combination of democracy and speculative market information processing futarchy. There is a short manifesto and a full paper (PDF).
The central idea is: Use democracy to express what you want, use prediction markets to evaluate how to reach these goals. People can give strategies which are traded after paying a small fee; when they seem to be efficient the get a payback, otherwise they loose the fee. Thus good strategies are rewarded, bad ones are not rewarded but cost an extra fee. Augmented GDP and other indicators give a measured value to the state of the country.
The central idea is: Use democracy to express what you want, use prediction markets to evaluate how to reach these goals. People can give strategies which are traded after paying a small fee; when they seem to be efficient the get a payback, otherwise they loose the fee. Thus good strategies are rewarded, bad ones are not rewarded but cost an extra fee. Augmented GDP and other indicators give a measured value to the state of the country.
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