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Why reCAPTCHA is Good for Humanity

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Last week we talked about KittenAuth, a novel CAPTCHA system used to differentiate between humans and spambots -- by using pictures of kittens. Today let's take a look at reCAPTCHA, the system in use by this very blog. What does it do, and why is it good for humanity?

What's a CAPTCHA?

First let's review the term CAPTCHA. It's a loose acronym for "Completely Automated Public Turing test to tell Computers and Humans Apart." The idea is to force humans to do a (relatively) simple task like read a few words presented in an image, then type them into the form -- but this trick only works if the task is hard for computers (ahem, spambots) to do.

CAPTCHA systems are used on forms all over the web in order to cut down on spam form submissions. If you've ever run a blog, you'll know that legions of spambots are crawling the web, submitting every form they find -- so having a CAPTCHA on the form drastically reduces form spam. However, in most CAPTCHA systems the text you type in is meaningless, purposely scrambled text. reCAPTCHA is different.

What's Different About reCAPTCHA?

reCAPTCHA was born when Luis von Ahn, an assistant professor at Carnegie Mellon, realized that millions of people were spending time typing meaningless words into forms. Why not turn this word-decipherment into useful work that helped with some common goal? What if there was a set of words (as images) that needed to be viewed and deciphered by humans? It turns out that book scanning projects (including the Internet Archive) have just this problem: when scanning a print book into a computer -- particularly an old book in poor condition -- some words can't be deciphered automatically by Optical Character Recognition (OCR) software, and need a human to figure them out. In order to get a good text-only copy of a scanned book, lots of human attention is needed.

So reCAPTCHA is conceptually simple: take the words the OCR software can't read and put them in front of human users. If multiple users decipher the same hard-to-read word using the same text, reCAPTCHA can safely assume that it has been properly deciphered, and feed that word back into the book scanning project, slotting it into its associated book. Thus, text that is by definition difficult or impossible for a computer to accurately scan has been deciphered by humans -- and the humans doing the work generally don't even know it!

Yeah, But...

There's one technical catch -- what's to stop people from typing in random gibberish as "decipherment" of the words? Given that reCAPTCHA by definition doesn't know the correct decipherment of its subject words, how can it judge whether you've gotten it right? To solve this problem, reCAPTCHA presents two words together: one unknown and one known (the latter meaning a word for which reCAPTCHA already has a good decipherment). You have to get the known word correct, and the unknown word is (as described above) compared with other users' decipherments to eventually determine whether it's correct. There's also an audio variant for users with visual impairment, in which they listen to spoken language and convert it to written text.

So next time you fill out a reCAPTCHA form when commenting on a Mental Floss blog post, remember: you're helping to digitize books!

Further reading: Carnegie Mellon press release, Wikipedia page, reCAPTCHA project site.

Shhh...super secret special for blog readers.

Google Street View Now Lets You Explore the International Space Station

Google Street View covers some amazing locations (Antarctica, the Grand Canyon, and Stonehenge, to name a few), but it’s taken until now for the tool to venture into the final frontier. As TechCrunch reports, you can now use Street View to explore the inside of the International Space Station.

The scenes, photographed by astronauts living on the ISS, include all 15 modules of the massive satellite. Viewers will be treated to true 360-degree views of the rooms and equipment onboard. Through the windows, you can see Earth from an astronaut's perspective and a SpaceX Dragon craft delivering supplies to the crew.

Because the imagery was captured in zero gravity, it’s easy to lose sense of your bearings. Get a taste of what ISS residents experience on a daily basis here.

[h/t TechCrunch]

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Bite Helper
New Gadget Claims to De-Itch Your Mosquito Bites
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Bite Helper

Summer can be an itchy time for anyone who wants to enjoy the outdoors. Mosquitos are everywhere, and some people are particularly susceptible to their bites and the itching that comes with them. A new product aims to stop the suffering. Bite Helper, reviewed by Mashable, is designed to stop your bites from itching.

Place the pen-like device over your swollen bite and it will begin to emit heat and vibrations designed to quell the itch. It’s meant to increase blood flow around the area to alleviate your pain, heating your skin up to 120°F for up to 45 seconds. It’s the size of a thin tube of sunscreen and is battery powered.

Most dermatologists advise applying cold to alleviate itching from insect bites, so the question is: Will heating up your skin really work? Bite Helper hasn’t been clinically tested, so it’s hard to say for certain how effective it would be. There has been some research to suggest that heat can help increase blood flow in general, but decrease histamine-induced blood flow in the skin (part of the body’s normal response to allergens) and reduce itching overall. In a German study of wasp, mosquito, and bee stings, concentrated heat led to a significant improvement in symptoms, though the researchers focused mostly on pain reduction rather than itching.

Bite Helper’s technique "seems like a legitimate claim" when it comes to localized itching, Tasuku Akiyama, who studies the mechanisms of itching at the University of Miami, tells Mental Floss. "The increase in the blood flow may increase the rate of elimination of itch mediator from the area." However, before that happens, the heat might also make the itch a little worse in the short-term, he cautions. This seems to be borne out by user experience: While Mashable's reviewer found that using the device didn’t hurt at all, his daughter found it too hot to bear for more than a few seconds.

If the device does in fact relieve itching, though, a few seconds of pain may be worth it.

Bite Helper is $25 on Amazon.

[h/t Mashable]


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