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rappatic

1,463 karma · joined December 16, 2020

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rappatic··on Turning a MacBook into a touchscreen with $1 of hardware (2018)
Oleophobic coating is standard on phones and tablets, which is part of why they don’t pick up fingerprints as easily.

Some brands offer coating you can DIY yourself (eg ProofTech OLEOPEL) but these seem mostly designed for phone screens. I don’t know whether they’d be as effective on laptop screens

rappatic··on How and why to take a logarithm of an image [video]
Similarly, it's possible to take the derivative of a song. You can use a Fourier transform to express the song's waveform as a series of sin and cosine functions, then take the derivative.

Imagine, for the sake of simplicity, you could express the song's waveform with the function 13 * sin(41x).

The derivative of this function is 533 * cos(41x).

Cosine, of course, is just a phase shifted sine, and the constant coefficient inside the function stays the same. So you're not changing anything about the shape of the wave, just stretching it vertically.

This has the effect of mimicking a "high pass filter," amplifying the volume of the highs.

rappatic··on No leap second will be introduced at the end of June 2026
Google and lots of other firms use a "leap smear" to hide the leap second from end users, essentially "smearing" the second across the hours before and after each leap.

https://developers.google.com/time/smear

rappatic··on Most of the US economy is in a recession
Well yeah, when you exclude all the successful and profitable sectors things do start looking bad.

Just in: most people are actually short! Excluding people over 6 feet tall, the average height is only 5 ft 8!

rappatic··on Show HN: AI agents run my one-person company on Gemini's free tier – $0/month
I guess it shouldn’t be surprising for this post to be LLM-written when the author’s point is that they use LLMs to write a bunch of social media posts, but it still makes me a little sad.
rappatic··on MacBook Neo
The M1 Air didn’t have MagSafe, but yeah agreed
rappatic··on MacBook Neo
> just unify the two already

Yeah but some people buy both, and apple wants to keep it that way

rappatic··on Leaving Google has actively improved my life
This is the way. Vote with your wallet!
rappatic··on Layoffs at Block
"ChatGPT, write a letter to my company about laying 40% of them off but don't capitalize anything"
rappatic··on Layoffs at Block
i'm gonna write this terrible news in all lowercase cause it's super aesthetic. maintain a bit of professionalism for the 4,000 people whose lives i'm throwing into turmoil? i don't think so, i have my shift key taped over so i don't accidentally show respect to anybody
rappatic··on Decided to fly to the US to buy some hard drives
There's no real arbitrage opportunity because he booked the hotel and flights on points. It likely would've been considerably more expensive overall if he'd booked in cash.
rappatic··on America's most partisan voters hold the most voting power
> His organization says 32 states currently don't have a single competitive congressional race

I agree that the system is broken, but this is not a very fair statistic. 5 states have only a single seat in the House of Representatives. A further 7 states have just two seats. In total, there are 23 states with 5 seats or fewer. These states are all small and rural, which doesn't exactly make for a diverse population and means the seats tend to be safe R. For the states with a single major city (like Omaha for Nebraska) that city typically has its own district, and will hence be safe D in a sea of safe R. It's only in the more populous, more diverse areas where you start to get a lot of people living together who disagree with each other. This is what creates competitive races.

rappatic··on Unreal numbers
I think this article should’ve used the Cauchy sequence method to construct the reals instead of Dedekind cuts. It would’ve built on the earlier mention of equivalence classes.
rappatic··on Assigning Open Problems in Class
This reminds me of my undergrad “discrete math” lecture notes, where my professor wrote the following in the unit on sets:

> This brings us to a fun problem for you to think about in your spare time: are there any infinite sets that have cardinality strictly between [the cardinality of the natural numbers] and [the cardinality of the real numbers]?

This is of course the famously undecidable continuum hypothesis (https://en.wikipedia.org/wiki/Continuum_hypothesis).

rappatic··on Mark Zuckerberg Lied to Congress. We Can't Trust His Testimony
That link leads to a PDF which says "The 2020 Federal Human Trafficking Report found that 65% of child sex trafficking victims recruited on social media were recruited from Facebook, with 14% being recruited on Instagram." This is a completely different statistic: the percentage of child sex trafficking victims recruited on social media vs. the percentage "of all child sex trafficking."
rappatic··on Mark Zuckerberg Lied to Congress. We Can't Trust His Testimony
Half of these examples aren't even lies. The right column of this table is full of whataboutisms and fabricated statistics. For example,

> Zuckerberg: "We don't allow people under the age of 13 on our service. So if we find anyone who's under the age of 13, we remove them from our service."

> What the evidence says: Internal document stating the goal for Meta to be the most relevant social products for kids worldwide. To do so, Meta will focus on "each youth life stage, ‘Kid’ (6-10), ‘Tween’ (10-13), and ‘Teen’ 13+."

The fact that Meta eventually wants to appeal to kids doesn't mean they currently allow kids on their platform.

And here's an example of a fabricated statistic:

> 79% of all child sex trafficking in 2020 occurred on Meta’s platforms. (Link)

That link leads to a PDF which says "The 2020 Federal Human Trafficking Report found that 65% of child sex trafficking victims recruited on social media were recruited from Facebook, with 14% being recruited on Instagram." This is a completely different statistic: the percentage of child sex trafficking victims recruited on social media vs. the percentage "of all child sex trafficking" (the vast majority of which does not occur through social media).

Doing stuff like this destroys the website's credibility when it comes to the actual lies.

rappatic··on Speed up responses with fast mode
Counterintuitively, I feel like this will not be super useful, at least for me. My bottleneck is MY ability to parse and understand LLM-generated code. The agent can code a lot faster than I can read and understand its output.
rappatic··on It's 2026, Just Use Postgres
Oh wow, the "Postgres for Developers, Devices, and Agents" company wants us to use Postgres?
rappatic··on County pays $600k to pentesters it arrested for assessing courthouse security
This happened in 2019. The wheels of justice turn very slowly.
rappatic··on Banned C++ features in Chromium
Yeah lord C++ is a gigantic language
rappatic··on Proof of Corn
I love the variety of people that come to HN. There are real farmers weighing on on the plausibility of this.
rappatic··on Can you slim macOS down?
Our machines all have CPUs that can execute on the order of 10^9 instructions every second. Why waste time worrying about a few hundred processes that use next to no CPU time?
rappatic··on An Elizabethan mansion's secrets for staying warm
> The house has lessons for how we can heat our homes more efficiently today

The problem in Europe isn't keeping warm in the winter but keeping cool in the summer. In part thanks to their near-total lack of AC in residential buildings, Europe has an extremely high heat-related death rate. 200k people per year die of heatstroke in Europe: this accounts for 36% of global heat-related deaths. This is despite Europe being only 9% of the world population, having a very cool climate in comparison to India and similar countries, and being among the richest regions in the world.

rappatic··on All about automotive lidar
> Many humans do a really bad job at driving, so I'm not sure we should try to emulate that

Agreed, but there are still really good human drivers, who still operate on sight alone. It's more about the upper bound, not the human average, that can be achieved with only sight.

rappatic··on All about automotive lidar
In the current state of self-driving tech, lidar is clearly the most effective and safest option. Yet companies like Tesla refuse to integrate lidar, preferring to rely solely on cameras. This is partially to keep costs down. But this means the Tesla self-driving isn't quite as good as Waymo, which sits pretty comfortably at level 4 autonomy.

But humans have no lidar technology. We rely almost solely on sight for driving (and a tiny bit on sound I guess). Hence in principle it should be possible for cars to do so too. My question is this: at what point, if at all, will self-driving get good enough to make automotive lidar redundant? Or will it always be able to make the self-driving 1% better than just cameras?

rappatic··on OpenAI declares 'code red' as Google catches up in AI race
> the company will be delaying initiatives like ads, shopping and health agents, and a personal assistant, Pulse, to focus on improving ChatGPT

There's maybe like a few hundred people in the industry who can truly do original work on fundamentally improving a bleeding-edge LLM like ChatGPT, and a whole bunch of people who can do work on ads and shopping. One doesn't seem to get in the way of the other.

rappatic··on Project Gemini
Why is everything named Gemini these days?
rappatic··on iPhone Pocket
Nothing like a $150 or $230 phone bag.
rappatic··on I Want You to Understand Chicago
> I view ICE as wholly illegitimate

Though you may find this surprising, your personal opinion on the legitimacy of an organization doesn’t actually have legal standing.

rappatic··on I Want You to Understand Chicago
> Agents with guns have chased a teacher into the school where she works

The agents actually attempted to pull over Ms. Galeano’s vehicle, but the male driver (with Galeano in the passenger seat) refused to stop despite the sirens and lights. The agents pursued the car, which sped into a shopping center, and Ms. Galeano fled the vehicle and ran into a daycare, attempting to barricade herself inside. She didn’t get all the way in and was arrested inside the vestibule. None of the kids witnessed the arrest.

Regardless of your thoughts on immigration and ICE, if a cop tries to pull you over, and instead you decide to speed off and barricade yourself inside a daycare, you’re probably going to get arrested.

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