91–100 of 122 posts
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>They're so good the treasury department buys them because they're better than the best systems out there. This phrasing is gold. "Our product is so good, the government buys it because it's better than the best thing out there." :)
The treasury's best testing mechanisms are destructive.
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Wow, that helps. "Principal components are linear combinations of original variables x1, x2, etc. So when you do SVM on PCA decomposition you work with these combinations instead of original variables." "What do you do to the data? My answer: nothing. SVMs are designed to handle high-dimensional data. I'm working on a research problem right now that involves supervised classification using SVMs. Along with finding so…
I'm an amateur in machine learning myself so I don't have a lot of knowledge of the details, but allow me to take a guess at what it's about. Support vector machines are a machine learning algorithm that works by taking data points in some (usually) high-dimensional space, and classifies them based on where they lie in relation to a boundary that (mostly) divides the positive examples from the negative ones. So one w…
Just as a simple example (stolen from the Caltech course which I highly recommend) if you look at points on a plane that form a circle and try to separate them with a line you're going to fail. I.e. your points are (x,y) and those in the circle are your fake dollar bill and those outside aren't. But you can take all these points and apply a non-linear transform, e.g. (x, y, xy, xxy, yyx, x+y, xx+y2), you get the idea... It turns out that now you can* separate the data into what's inside and outside the circle. The problem is you just increased your so called VC dimension of the model and you might overfit the data and not learn anything. SVMs let you get infinite numbers of combinations, without overfitting and with cheap calculations... Pretty neat.
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This is one of the things that made me really see the value of free software. How do you mean? Is there much (legal) value to be had from image software that can process accurate scans of currency? I'm just kind of confused here, what value you speak of.
Because my software should never tell me that I can't do something for non-technical reasons. Assuming I'm a criminal is wrong. If I was a criminal, breaking the law is my decision, and my software should not impede my ability to do so.
The Photoshop anti-counterfeiting stuff? It just scares off amateurs with an inkjet who don't realize every page from their printer has a tiny coded tracking mark that identifies the printer, date, and time.
When I was in college (99-2000ish, maybe?), one of my roommates was an art major with a graphic design bent, and he had this high end printer and would copy and print $1 bills and take 20 at a time over to the vending machines around the corner from our apartments once a week or so. After about a month of doing this, the machines disappeared. Of course, he's the same roommate who later got arrested for wire fraud and…
Similar. A friend of mine used an epson stylus printer (new on the market then) and a scanner to copy £20 notes. They were inserted into the change machine in the local gambling arcade type place. It was stupid enough to accept a single sided copy. Out popped pound coins. He now works for GCHQ which is funny. Edit: just to add that these change machines were really naff and obviously built by the lowest bidder.
DIP switches are set for various options one being accept face up (two-way), other options turn on or off acceptance of certain denomination bills and maintenance features such as calibration.
Even now modern acceptors allow this, although four-way acceptance is often preferred by the customer.
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That does seem like an ideal application for support vector machines. Do you know what kind of basis they use for SVM? Is it the usual exponential approach or something more specific to currency features?
Yes, I know. No, I can't tell you.
When I was in college (99-2000ish, maybe?), one of my roommates was an art major with a graphic design bent, and he had this high end printer and would copy and print $1 bills and take 20 at a time over to the vending machines around the corner from our apartments once a week or so. After about a month of doing this, the machines disappeared. Of course, he's the same roommate who later got arrested for wire fraud and…
Given the cost of high quality ink and paper, one wonders how much less than $1 those bills cost to make.
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> It makes me wonder what more sophisticated criminals can get away with. A lot. http://en.wikipedia.org/wiki/Superdollar
That was a fascinating read, thanks! Tl;dr: 100$ bills produced in all likelihood by a foreign government (suspects are North Korea, Syria, Iran) or maybe criminal gangs are so well done that they are practically indistinguishable from the original. The numbers printed seem to be pretty low though, and not nearly enough to endanger the economy in any way. Probably its hard to launder the money?
This guy made beautifully artistic bills that didn't look official currency and then made purchases with them at their face value: $100, $500, etc.
When I was in college (99-2000ish, maybe?), one of my roommates was an art major with a graphic design bent, and he had this high end printer and would copy and print $1 bills and take 20 at a time over to the vending machines around the corner from our apartments once a week or so. After about a month of doing this, the machines disappeared. Of course, he's the same roommate who later got arrested for wire fraud and…
When I was in the States, some buddies had some Philippine Peso coins which weigh and are roughly the same size as quarters. They used a few if these to operate coin-based laundry machines.
The laundry/vending machines are an interesting case because there's a decent chance that the the vendors would just be taking bags of coins to the bank where, presumably, the Pesos would be kicked out correctly. Even then, if there were only a small number of pesos, they probably just passed them on at someone else's vending machine, or in other cash person-to-person transactions.
It's hilarious to me that, while you can argue about what currencies are backed by, at the end of the day all that matters is that something spends. If something spends like a quarter, it's a quarter.
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Fun fact: The treasury department won't tell you what is actually on the bills. In fact, none of the governments will. You can analyze them till you're blue in the face, under whatever light or circumstances you want, but the treasury department won't tell you what security measures are on the bill, nor when they change them. Additionally, they sometimes change during print runs, and issues.
Fun fact: you are asking the wrong branch of the government. The Secret Service will happily tell you about security features of currency, and behind closed doors help you build methods to detect counterfeits if you have a reasonable justification. http://www.secretservice.gov/know_your_money.shtml