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Mata Hari: Famous Spy or Creative Storyteller?

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Nearly everyone has heard of Mata Hari, one of the most cunning and seductive spies of all-time. Except that statement isn't entirely true. Cunning and seductive, yes. Spy? Probably not. 

Margaretha Geertruida Zelle was the eldest daughter of a hat store owner who was quite wealthy thanks to some savvy oil investments.  When her mother died, her father remarried and shuffled his children off to various relatives. To escape, an 18-year-old Margaretha answered an ad in the paper that might have read something like this: "Dutch Colonial Army Captain Seeks Wife. Compatibility not important. Must not mind blatant infidelity or occasional beatings."

She had two children with Captain Rudolf MacLeod, but they did nothing to improve the marriage. He brazenly kept a mistress and a concubine; she moved in with another officer. Again, probably looking to escape her miserable existence, Margaretha spent her time in Java (where the family had relocated for Captain MacLeod's job) becoming part of the culture, learning all about the dance and even earning a dance name bestowed upon her by the locals - "Mata Hari," which meant "eye of the day" or "sun."

Her son died after being poisoned by an angry servant (so the MacLeods believed).

Margaretha divorced her husband, lost custody of her daughter and moved to Paris to start a new life for herself in 1903.  Calling upon the dance skills she had learned in Java, the newly restyled Mata Hari became a performer, starting with the circus and eventually working her way up to exotic dancer. 

To make herself seem more mysterious and interesting, Mata Hari told people her mother was a Javanese princess who taught her everything she knew about the sacred religious dances she performed. The dances were almost entirely in the nude.

Thanks to her mostly-nude dancing and tantalizing background story, she was a hot commodity all over Europe. During WWI, this caught the attention of British Intelligence, who brought her in and demanded to know why she was constantly traipsing across the continent. Under interrogation, she apparently told them she was a spy for France - that she used her job as an exotic dancer to coerce German officers to give her information, which she then supplied back to French spymaster Georges Ladoux. No one could verify these claims and Mata Hari was released.

Not too long afterward, French intelligence intercepted messages that mentioned H-21, a spy who was performing remarkably well. Something in the messages reminded the French officers of Mata Hari's tale and they arrested her at her hotel in Paris on February 13, 1917, under suspicion of being a double agent.

Mata Hari repeatedly denied all involvement in any spying for either side. Her captors didn't believe her story, and perhaps wanting to make an example of her, sentenced her to death by firing squad. She was shot to death on October 15, 1917.

In 1985, one of her biographers convinced the French government to open their files on Mata Hari. He says the files contained not one shred of evidence that she was spying for anyone, let alone the enemy. Whether the story she originally told British intelligence was made up by them or by her to further her sophisticated and exotic background is anyone's guess. 

Or maybe she really was the ultimate spy and simply left no evidence in her wake.

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Name the Author Based on the Character
May 23, 2017
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