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foo92691

272 karma · joined April 21, 2021

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foo92691··on The Resilience of Costco (2018)
> How is it possible that they cannot give me an accurate inventory of the items in the stores near me?

It's absolutely intentional. It means you have to browse the store. And if something piques your interest -- you know you can't wait to buy it "next time" since it might not be there.

foo92691··on Airbnb nightly rates shot up 36% in 3 years
It includes the cleaning fee and Airbnb service fee, but inexplicably, excludes taxes.
foo92691··on Airbnb nightly rates shot up 36% in 3 years
But it's not really the "total price". It doesn't include taxes.
foo92691··on Half of Americans now believe that news organizations deliberately mislead them
Only half?
foo92691··on American Airlines agrees to purchase Boom Supersonic Overture aircraft
The fuel burned by an aircraft is almost certainly the dominant portion of its lifecycle carbon emissions. I expect the carbon emissions due to its manufacture are negligible by comparison. Have you seen a source either way?
foo92691··on American Airlines agrees to purchase Boom Supersonic Overture aircraft
According to their propaganda, they are going to make jet transport cheaper AND faster AND greener.

I see no evidence that this is at all realistic, and a lot of evidence to the contrary.

Do they even have a story explaining how their new supersonic jet could possibly reduce costs?

foo92691··on American Airlines agrees to purchase Boom Supersonic Overture aircraft
Agreed. Boom claims they will be "sustainable" because they are going to invent some kind of synthetic biofuel.

Wait, it looks like I either misremembered that claim, or they have backed away from it:

> "Overture’s fleet will be able to run on 100% sustainable aviation fuels."

https://boomsupersonic.com/sustainability

Color me skeptical. Making existing aviation more climate-friendly would be a much more worthy goal than this ridiculous supersonic vanity project.

foo92691··on Twilio incident: What Signal users need to know
Those are features.
foo92691··on Welcome to the M1 Windows project
I'm a bit shocked that it would even be possible for a third party to implement such a thing without rebuilding Windows itself. Is it a matter of implementing "device drivers"?
foo92691··on Using a "proper" camera as a webcam
"relatively inexpensive"
foo92691··on Open Golf: A cross-platform minigolf game written in C
What's the TLDR on how to compile the C code to run in the browser?
foo92691··on Things you notice when you quit the news (2016)
The Economist is also like 100+ pages per week. Very hard to consume without significant dedication.
foo92691··on Two weeks later David Bennett is alive, his pig’s heart beating soundly
"The New York Post (NY Post) is a conservative[8] daily tabloid newspaper published in New York City. The Post also operates NYPost.com, the celebrity gossip site PageSix.com, and the entertainment site Decider.com."

https://en.wikipedia.org/wiki/New_York_Post

foo92691··on Ask HN: Should I publish my research code?
Yes, absolutely. Next question?
foo92691··on DNS doesn't “propagate”
Does it not anymore? Or is it like KFC?
foo92691··on Show HN: A place for feedback on PCB designs
In my experience, ALL designs at $corp are "IP protected."
foo92691··on Vials labeled ‘smallpox’ are found in Pennsylvania laboratory
Deciding to culture the samples, versus just destroying them without analysis, must be accompanied by an interesting risk/benefit analysis.
foo92691··on Astrophysicists unveil glut of gravitational-wave detections
The microphone analogy is particularly apt, because the signals are also audio-frequency. You can listen to them. Sometimes in the control room we play the output on a loudspeaker. It can help in tuning the instrument (most of what you hear is noise).
foo92691··on Astrophysicists unveil glut of gravitational-wave detections
This was in fact accomplished and is attempted for many of the detections.
foo92691··on Justice Department sues Uber for overcharging people with disabilities
Wait fees seem pretty reasonable. Maybe the solution is to have them subsidized by the government for qualified individuals.
foo92691··on Astrophysicists unveil glut of gravitational-wave detections
So far all of the signals observed by LIGO are from sources that we expected would exist.

The most exciting thing would be to observe an unexpected signal.

foo92691··on Astrophysicists unveil glut of gravitational-wave detections
There is no upper limit to the wavelength of gravitational waves. However, the lowest frequency that we can currently detect is around 10-100 Hz. Diving the speed of light (3e8 m/s) by (10 Hz) gives 3e7 meters. 30,000 km. The upper end of our frequency range is currently around 8 kHz which corresponds to 37.5 km if I did the math right.

LISA will be sensitive to much lower frequencies (longer wavelengths). NanoGrav also searches for these lower frequency signals.

We expect most gw's to be of very low frequency. High frequency g.w.s require tremendous mass and acceleration to generate. They are only generated in the final moments of black hole collisions as far as we know.

foo92691··on Astrophysicists unveil glut of gravitational-wave detections
Extensive computer modeling is used to predict the expected waveforms, and then we fit the observed waveforms to the expected ones.
foo92691··on Astrophysicists unveil glut of gravitational-wave detections
Also the experimentalists get very antsy when they/(we) can't touch the instrument. :-)
foo92691··on Astrophysicists unveil glut of gravitational-wave detections
This is what you're waiting for: https://en.wikipedia.org/wiki/Laser_Interferometer_Space_Ant...
foo92691··on Astrophysicists unveil glut of gravitational-wave detections
You can think of each individual detector producing a single-channel audio signal. By combining the signals from multiple detectors it's possible to determine where the signal is coming from. But the output is neither a picture nor a single pixel: it's a brief blip of a few seconds of audio-frequency time series.

A decent analogy is to think of each LIGO detector not as a camera but a microphone.

foo92691··on Astrophysicists unveil glut of gravitational-wave detections
And resonant cavities, the best mirrors ever made, and a huge amount of cleverness and work over 40+ years.
foo92691··on Legacy Train Control System Stabilisation (2012) [pdf]
"Copyright © 1978-2021 Berkshire Hathaway Inc."

Ok the web page looks old but maybe not that old

foo92691··on Optimizations Enabled by -ffast-Math
Seems like it might depend on the FPU rounding mode?

https://en.wikipedia.org/wiki/Signed_zero#Arithmetic

foo92691··on A Graduate Course in Applied Cryptography
Applied Cryptography is an excellent book, but it is very very old. Nearly 25 years old.

The foreword of the semi-recent (2015) "20th anniversary edition" (which appears to be a reissue of the 2nd edition) even recommends that you look for a more modern reference.

And one of the lessons of the last decades is that programmers should generally not be implementing their own cryptography unless that is their specialty.

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