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What's the Deal With the Black Box?

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I have spent my life on Mars, in a cave, with my fingers in my ears. What, pray tell, is a flight recorder?

Flight recorders are devices used in aircraft to record—you guessed it—flight information, which then may be used to aid any investigations into aircraft accidents or incidents.

There are two common types of flight recorders: flight data recorders (FDR) and cockpit voice recorders (CVR). FDRs record various aircraft performance parameters and operating conditions, such as time, altitude, airspeed, heading, aircraft attitude, flap position, control-column position, fuel flow and even whether the smoke alarms in the lavatory went off. The Federal Aviation Administration (FAA) requires that older commercial aircraft record a minimum of 11 to 29 parameters, depending on the size of the craft. Newer aircraft (built after 8-19-02) are required to record at least 88 parameters.

CVRs record the audio environment in an aircraft's cockpit, including conversations, ambient sounds and radio communications between the cockpit crew and others.

The FAA requires that the recording duration is a minimum of thirty minutes, and most magnetic-tape CVRs employ a continuous loop of tape that cycles every 30 minutes, recording new material over the old. Sometimes, the two recorders are combined into a single FDR/CVR unit.

Some aircraft also employ a quick access recorder (QAR), which records data on a removable storage device and can be accessed with a more-or-less regular desktop computer (FDRs and CVRs require special equipment to read the recording). QARs are usually scanned during the flight for deviations from normal operations and/or parameters so that problems can be detected and fixed before an accident even occurs.

If they're used to investigate crashes, they must be pretty tough, right?

If I had to rate the toughness of a flight recorder, I'd put it right up there with Bruce Willis in Die Hard and Clint Eastwood in Dirty Harry. Flight recorders are carefully engineered and constructed to withstand some less than comfortable conditions and usually have an impact tolerance of 3,400 Gs (one G is the g-force acting on a stationary object resting on Earth's surface. It is the force of Earth's gravity and equal to however much that object weighs. In an 3,400-G impact, the flight recorder hits something at a force equal to 3,400 times its own weight). They also have a fire resistance of 2012° F/30 minutes. They can withstand water pressure when submerged up to 20,000 feet underwater and usually have an underwater locator beacon with a six-year shelf life and 30-day operation capability.

The information the recorder gathers is stored within the device on a crash-survivable memory unit protected by aluminum housing, one inch of dry-silica material high-temperature insulation and a ¼-inch thick stainless-steel or titanium cast shell.

For high visibility in wreckage, the outside of flight recorders are coated in heat-resistant, reflective red, yellow or orange paint.

So, if it's painted red, yellow or orange, why is it called the black box?

There are a few theories about that.

The first explanation goes that after an early flight recorder for commercial flights—the "Red Egg"—was unveiled, a journalist pronounced it to be a "wonderful black box."

Another explanation says that when new electronic instruments were being added to Royal Air Force planes during World War II, they were covered in hand-made metal boxes and then painted black to prevent reflection. These electronics came to be collectively known as "black boxes" and the term then made its way into civil aviation and general usage post-war.

Still another explanation has it that the name is simply borrowed. In science and engineering, a "black box" is a device, system or object that can viewed solely in terms of input, output and transfer characteristics without any knowledge of its internal workings.

How do you read a black box and what do you do with the info?

In the United States, after a black box is located, it's usually brought to the computer labs of the National Transportation Safety Board (NTSB). Transporting the boxes there is done with the utmost care so no further damage is done to the memory unit. If the plane crashed into a body of water, the black box is usually transported in a cooler of water until it can be handled and disassembled properly.

At the NTSB labs, the black box data is downloaded onto computers equipped with readout systems and analysis software supplied by the black box manufacturers. Extracting the data from a relatively undamaged recorder only takes a few minutes. In the case of a badly dented or burned recorder, the box has to be disassembled and the memory units removed, cleaned and connected to a working recorder.

The data on a CVR is reviewed and interpreted by a team of experts, usually including a representative from the airline involved in the accident, a representative from the airplane manufacturer, an NTSB transportation safety specialist and an NTSB air safety investigator. Meanwhile, the data on an FDR is used by NTSB investigators to reconstruct the events and conditions of the flight (FDRs are also used to analyze aircraft engine performance, the condition of aircraft parts and instruments and air safety issues). These processes can take weeks or even months, but, ideally, provide the investigators with some insight into the final moments of the flight and what caused the accident.

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iStock // Ekaterina Minaeva
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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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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Live Smarter
Working Nights Could Keep Your Body from Healing
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The world we know today relies on millions of people getting up at sundown to go put in a shift on the highway, at the factory, or in the hospital. But the human body was not designed for nocturnal living. Scientists writing in the journal Occupational & Environmental Medicine say working nights could even prevent our bodies from healing damaged DNA.

It’s not as though anybody’s arguing that working in the dark and sleeping during the day is good for us. Previous studies have linked night work and rotating shifts to increased risks for heart disease, diabetes, weight gain, and car accidents. In 2007, the World Health Organization declared night work “probably or possibly carcinogenic.”

So while we know that flipping our natural sleep/wake schedule on its head can be harmful, we don’t completely know why. Some scientists, including the authors of the current paper, think hormones have something to do with it. They’ve been exploring the physiological effects of shift work on the body for years.

For one previous study, they measured workers’ levels of 8-OH-dG, which is a chemical byproduct of the DNA repair process. (All day long, we bruise and ding our DNA. At night, it should fix itself.) They found that people who slept at night had higher levels of 8-OH-dG in their urine than day sleepers, which suggests that their bodies were healing more damage.

The researchers wondered if the differing 8-OH-dG levels could be somehow related to the hormone melatonin, which helps regulate our body clocks. They went back to the archived urine from the first study and identified 50 workers whose melatonin levels differed drastically between night-sleeping and day-sleeping days. They then tested those workers’ samples for 8-OH-dG.

The difference between the two sleeping periods was dramatic. During sleep on the day before working a night shift, workers produced only 20 percent as much 8-OH-dG as they did when sleeping at night.

"This likely reflects a reduced capacity to repair oxidative DNA damage due to insufficient levels of melatonin,” the authors write, “and may result in cells harbouring higher levels of DNA damage."

DNA damage is considered one of the most fundamental causes of cancer.

Lead author Parveen Bhatti says it’s possible that taking melatonin supplements could help, but it’s still too soon to tell. This was a very small study, the participants were all white, and the researchers didn't control for lifestyle-related variables like what the workers ate.

“In the meantime,” Bhatti told Mental Floss, “shift workers should remain vigilant about following current health guidelines, such as not smoking, eating a balanced diet and getting plenty of sleep and exercise.”