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Jeremy Bentham Designs a Prison

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jepler
2 hours ago
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Earth, Sol system, Western spiral arm
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The Thermochromic Display You Didn’t Know You Needed

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We love unique ways of displaying data here at Hackaday, and this ingenious thermochromic display created by [Moritz v. Sivers] more than fits the bill. Using sheets of color changing liquid crystals and careful temperature control of the plates they’re mounted on, he’s built a giant seven-segment display that can colorfully (albeit somewhat slowly) show the current temperature and humidity.

The sheets of temperature sensitive liquid crystals are a bit like flattened out Mood Rings; they starts out black, but as heat is applied, their color cycles through vibrant reds, greens, and blues. The sheets are perhaps best known as the sort of vaguely scientific toys you might see in a museum gift shop, but here [Moritz] has put their unique properties to practical use.

To achieve the effect, he first cut each segment out of copper. The crystal sheets were applied to the segments, thanks to their handy self-stick backing, and the excess was carefully trimmed away. Each segment was then mounted to a TES1-12704 Peltier module by way of thermally conductive epoxy. TB6612FNG motor controllers and a bevy of Arduino Nano’s are used to control the Peltier modules, raising and lowering their temperature as necessary to get the desired effect.

You can see the final result in the video after the break. It’s easily one of the most attractive variations on the classic seven-segment display we’ve ever seen. In fact, we’d go as far as to say it could pass for an art installation. The idea of a device that shows the current temperature by heating itself up certainly has a thoughtful aspect to it.

This actually isn’t the first display we’ve seen that utilized this concept, though it’s by far the largest. Back in 2014 we featured a small flexible display that used nichrome wires to “print” digits on a sheet of liquid crystals.

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jepler
3 hours ago
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DSA-4503 golang-1.11 - security update

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Three vulnerabilities have been discovered in the Go programming language; "net/url" accepted some invalid hosts in URLs which could result in authorisation bypass in some applications and the HTTP/2 implementation was susceptible to denial of service.

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jepler
16 hours ago
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hummm doesn't that mean all the go software has to be rebuilt now? great idea, static linking all go executables.
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Should HTTPS Certificates Expire After Just 397 Days?

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Google has made a proposal to the unofficial cert industry group that "would cut lifespan of SSL certificates from 825 days to 397 days," reports ZDNet. No vote was held on the proposal; however, most browser vendors expressed their support for the new SSL certificate lifespan. On the other side, certificate authorities were not too happy, to say the least. In the last decade and a half, browser makers have chipped away at the lifespan of SSL certificates, cutting it down from eight years to five, then to three, and then to two. The last change occured in March 2018, when browser makers tried to reduce SSL certificate lifespans from three years to one, but compromised for two years after pushback from certificate authorities. Now, barely two years later after the last change, certificate authorities feel bullied by browser makers into accepting their original plan, regardless of the 2018 vote...

This fight between CAs and browser makers has been happening in the shadows for years. As HashedOut, a blog dedicated to HTTPS-related news, points out, this proposal is much more about proving who controls the HTTPS landscape than everything. "If the CAs vote this measure down, there's a chance the browsers could act unilaterally and just force the change anyway," HashedOut said. "That's not without precendent, but it's also never happened on an issue that is traditionally as collegial as this. "If it does, it becomes fair to ask what the point of the CA/B Forum even is. Because at that point the browsers would basically be ruling by decree and the entire exercise would just be a farce."

Security researcher Scott Helme "claims that this process is broken and that bad SSL certificates continue to live on for years after being mississued and revoked -- hence the reason he argued way back in early 2018 that a shorter lifespan for SSL certificates would fix this problem because bad SSL certs would be phased out faster."

But the article also notes that Timothy Hollebeek, DigiCert's representative at the CA/B Forum argues that the proposed change "has absolutely no effect on malicious websites, which operate for very short time periods, from a few days to a week or two at most. After that, the domain has been added to various blacklists, and the attacker moves on to a new domain and acquires new certificates."
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jepler
1 day ago
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1. Nobody can pretend that they can make devices that depend on a static SSL trust chain for their entire useful life
2. The velocity with which every part of the SSL toolchain can remove outdated crypto support increases
3. Fully automated renewals work (except for EV, which browsers ALSO want to kill)
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How Should Schools Grade Unexpected-But-Correct Answers On Coding Tests?

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There can be more than one correct answer for academic tests of programming ability, writes long-time Slashdot reader theodp: Take the first of the Free-Response Questions in this year's AP CS A exam, which asked 70,000 college-bound students to "Write the static method numberOfLeapYears, which returns the number of leap years between year1 and year2." The correct answer, according to the CollegeBoard's 2019 Scoring Guidelines, entails iterating over the range of years and invoking a provided helper method called isLeapYear for each year.

Which does work, of course, but what if a student instead took an Excel-like approach to the same problem that consists of a (hopefully correct!) single formula with no iteration or isLeapYear helper function? Would that be a worse — or better -- example of computational thinking than the endorsed AP CS A Java-based solution? (Here's a 7-minute AP Conference discussion of how to correctly grade this problem)?

So, how have you seen schools and companies deal with unexpected-but-correct approaches to coding test questions?
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jepler
1 day ago
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At least right at this second, the text of the question says, in part, "You must use isLeapYear appropriately to receive full credit." (inside link "Free-Response Questions"). This makes the scoring of the "clever" method pretty clear: 1/5, or 2/5 if a useless variable is assigned the answer and then returned.

Why is this fair? Well, of course the big #1: Tests are a test of the test-taking skill. #2 would be: you didn't see the implementation of isLeapYear, which might even be subject to change, since leap years are a matter of human law and not physical law. So your clever numberOfLeapYears method will become wrong if isLeapYear changes or is different than what you thought.
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This Photographer’s Passport Photo Shoots Are… Different

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Photographer Max Siedentopf has a new project that examines one of the most boring types of photography: the passport photo. The series shows that even though passport photos need to be boring, the photo shoots themselves don’t.

Official passport photo requirements are extremely restrictive and specify the exact framing (centered with the subject facing straight on), lighting (a clear background with no shadow), and facial expression (no smiling).

“It seems almost impossible for any kind of self-expression,” Siedentopf says. His project, titled Passport Photos, “tries to challenge these official rules by testing all the things you could be doing while you are taking your official document photo.”

And indeed, there are a lot of things you could be doing…

Siedentopf actually didn’t tell his subjects that the photo shoot they were agreeing to was anything other than an ordinary passport shoot.

“They thought they were just there to take a normal passport photo,” Siedentopf tells Fast Company. “Some were pleasantly surprised, some slightly confused, and a few were left very disturbed.”

You can find more of Siedentopf’s work on his website.

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rocketo
2 days ago
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seattle, wa
jepler
2 days ago
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1 public comment
fxer
1 day ago
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Trenchy Toaster is smiling, try again
Bend, Oregon
dukeofwulf
1 day ago
I was thinking the same about mop lady.
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