Value-at-Risk Math-Model Failure
January 6th, 2009 by Jan-Mark![]()
“It was an unhedged bet, or what was called on Wall Street a “naked put,” meaning that he bet everyone on one outcome: he bet in favor of the large probability of making a small amount of money, and against the small probability of losing a large amount of money-and he lost. [...] He ran through a hundred and thirty million dollars — his cash reserves, his savings, his other stocks — and when his broker came and asked for still more he didn’t have it.“
From a very long but very good story on financial risk analysis. The main gist:
“Relying on Value at Risk (VaR) and other mathematical models to manage risk was a no-brainer for the Wall Street crowd [...] Nassim Nicholas Taleb, who likens VaR to ‘an air bag that works all the time, except when you have a car accident.’“
(source: /.)
Help Me
January 5th, 2009 by Jan-MarkWhat better way to start off the new year with a personal note on new years resolutions? I would like to solicit everybody’s help. But first let me explain the problem. As a young child I experimented with many a disorder: MBD, Rett syndrome, ADHA, Aperger’s, AHA, autism, several ASDs, PDD-NOS… The list is endless. I would like to declare however, I never inhaled. After a life of applied behavior analysis in all it’s forms, and countless, fruitless social skills therapies, I settled for being a nerd, because currently that is the most socially acceptable excuse for most of what I do to other people. Can you guess which one of the two characters I strongly identify with in the cartoon below?
You guessed it. The guy with the glasses. You really have to feel for the guy. Don’t you just hate all those interruptions?
So here is my request: Would you please, if I talk too loud or too long, gently point out to me that you prefer me to talk less (loud)? Thank you, because I frankly don’t think I will be able to realize my resolution this year, without all your help. Don’t laugh, this is not a joke.
HAPPY NEW YEAR
January 2nd, 2009 by Jan-Mark
Let’s all assume less this year!
Let’s all exaggerate a little this year!
Let’s all be a little commercial this year!.
Let’s all do as we have been impregnated.
BE HAPPY IN 2009 ! ! !
Yoshimoto Cube
January 1st, 2009 by Jan-Mark
(soruce: MetaFilter, thanks John)
Here is also a clear, do it yourself instruction video.
Never Underestimate the Power of Play Station
December 31st, 2008 by Jan-Mark
The CCC has used brute force (using 200 PS3’s) to generate a intermediate CA certificate. This allows them to make (most) all browsers trust what ever site the CCC wants. This is ideal for phishing sites. A user would not be able to tell the difference between their electronic banking site and some criminal’s site. I’ll repeat that. No user would be able to detect in anyway they were not using the bank’s secure site. Let me say that again. Every time you do some transaction with your bank over the Internet, you might be handing your account over to criminals and there would be no way for you to detect that until after they took you money. And not just banks, it’s the same with e-bay, amazon, paypal, you name it.
The nasty part of it, is that given the tree like structure of trust, you only need to crack one secret, and the whole structure is worthless. This in fact is so dangerous, that the CCC chose to crack an old certificate that expired years ago.
(links (een paar van vele): NRC, /., Hack-a-Day, CCC, 25C3)
Cartoon
December 30th, 2008 by Jan-MarkGeek Music
December 30th, 2008 by Jan-MarkBad Timing
December 29th, 2008 by Jan-Mark“Don’t be the laughingstock of your friends when you shout ‘Happy New Years’ a second too early … The International Earth Rotation and Reference Systems Service has announced that a leap second will be added on December 31, 2008 at 23h 59m 60s, meaning that this year will be exactly one second longer. The last leap second occurred Dec 31, 2005, they are added due to fluctuations in the rotational speed of the earth.“
(soruce: /.)
Talking about bad timing! I know the difference between UTC and UT1 cannot exceed 0.9 seconds, so maybe doing it June 1st, 2009 would be too late, but why do they have to choose the exact moment that everybody will be counting down to?
1.7 Grbps, WOW
December 29th, 2008 by Jan-Mark“Using semiconductor lasers, scientists from Takushoku University, Saitama University, and NTT Corporation achieved random number rates of up to 1.7 gigabits per second, which is about 10 times higher than the second-best rate, produced using a physical phenomenon. Future work may center on devising laser schemes that can achieving rates as high as 10 Gbps.“
(source: /.)
Note that the responses on /. are very funny (some even educational) to read, as usual. As a side note, this really is a big deal. Usually, fast generators (like Mersenne Twisters) are not secure and (pseudo) secure generators like (Blum Blum Shub) are not fast. Some people are so in need for a fast /dev/random that they even cote webcams with radioactive material to increase the entropy in their random pool. Pointlogic Galloper system, for example, slurps random bits like there is no tomorrow.

