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bmiranda

158 karma · joined October 8, 2012

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bmiranda··on High-speed rail in California was a disaster, but there’s a better way
Even in Japan it's cheaper to fly between Osaka and Tokyo than take the train. The train is a lot more convenient, though.

There are only a few corridors where high speed rail makes sense. Northeast US. Texas Central Railway is even trying to build a line between Houston and Dallas.

Building out everywhere though is a surefire way to rack up debt. Look at Japan, which is touted as a high-speed rail success story. Although the Osaka-Tokyo route is profitable (and very beneficial to their economy), the rest of their high-speed rail network essentially bankrupted JR Rail. JR Rail ended up being privatized, with most of the debt being funneled into a holding company owned by the government. JR East/Central are operating off of a high-speed network they essentially got for free.

bmiranda··on Google One
For a moment I thought it was going to be another chat app.

Instead it's... something? A one sentence description at the beginning of the page wouldn't hurt...

bmiranda··on Rediscovering My Daughter Through Instagram
Landscape pictures can serve as a reminder of what you were doing, a sort of diary. Sure, you could find professional photos, but they won't be as rooted in your memory.

By looking at an old photo you remember where you were, what you were doing, and _why_ you decided to take the photo.

In other words, while a pro may be able to capture the location better, they won't capture your memory of visiting it as well.

bmiranda··on The Reason We Haven’t Directly Detected Dark Matter
MOND does work a lot better than Lambda Cold Dark Matter (L-CDM)... but only for explaining the rotation of galaxies. It can explain this rotation almost perfectly given only the mass distribution: no tuning is required. Dark matter, on the other hand, has issues with dwarf galaxies and has no predictive power: you just fit the dark matter to the results you observe (Which is why you end up with some dwarf galaxies that are almost entirely composed of dark matter, and ones that almost have none. With MOND it just works).

Of course MOND can't really explain the third peak of the cosmic microwave background radiation, so it isn't perfect either. It is also phenomenological, with no underlying physical theory at the moment. Still, it's surprising that it does work at all.

I should also mention that the bullet cluster, which is touted as proving dark matter, causes issues for dark matter as well as MOND. The velocities involved in the collision are higher than can be explained by the current dark matter models. MOND kind of sucks at dealing with clusters, as well.

TL;DR MOND is a lot better than LCDM at explaining galaxy dynamics, LCDM is a lot better than MOND at explaining the cosmic background radiation. Both aren't that great at dealing with clusters (but you can also make dark matter work with enough fiddling).

https://tritonstation.wordpress.com/2018/09/04/dwarf-satelli...

bmiranda··on The F-35 Is a $1.4 Trillion National Disaster
Although there are teething issues, for US allies the unit the F-35 is attractive due to a unit cost which is lower than any of its competitors (such as the Eurofighter Typhoon).

For domestic use, the F-35B STOVL jet used by the Marines is a dramatic improvement in range and capabilities over the Harrier.

The F-35A/C are less of an improvement, but I would by no means call them a failure. It's easy to criticize a program due to cost overruns and mismanagement, but that doesn't mean the end result is bad. At the very least it's a sunk cost now, so we'll just have to deal with it.

bmiranda··on New Zealand startup successfully launches rocket
It's worth mentioning that while electric turbopumps are a lot better that pressure-fed designs, for larger engines they aren't as effective as using pre-burners (due to the weight of the batteries).

It does make the design much simpler, though.

bmiranda··on Monopoly was invented to demonstrate the evils of capitalism
I think this article misses the point of Georgism: that the land tax replaces all other taxes.

In other words, while land belongs to the government (people), individuals are entitled to the entire product of their labor (as well as returns on capital). Georgism is simultaneously extremely Communistic and Capitalistic.

bmiranda··on Which GPU(s) to Get for Deep Learning
Not having fast FP64 is a design decision. Space isn't free, and FP64 takes up a lot of space that could be used on delivering higher FP32 perf, which is more important for video games.
bmiranda··on Y Combinator head who pushes basic income is reportedly running for office
Well, he's not Gavin Newsom, so good luck if this is true!
bmiranda··on China's $1T Plan to Shake Up the Economic Order
What should the US do than? Spend our tax dollars on foreign handouts?

If US companies want to invest in SE Asia there is nothing stopping them.

bmiranda··on Volta: Advanced Data Center GPU
Google's hardware is for inference, not training.
bmiranda··on Volta: Advanced Data Center GPU
815 mm^2 die size!

That's at the reticle limit of TSMC, a truly absurd chip.

bmiranda··on [dead]
A bit suspicious right before the US election, maybe it's under attack.

We'll find out soon enough.

bmiranda··on Across the USA by Train for Just $213
Railroads in the US are privately owned, for the most part.
bmiranda··on SpaceX – Launch Vehicle Failure
Cargo dragon doesn't have a pad abort system.

Dragon 2 would be able to escape just fine, though. Cargo dragon could _technically_ survive if didn't get blown up too much.

bmiranda··on Lab 1: Booting a PC
I took the class (6.828) last semester at MIT, and the labs do a great job of handling a lot of the annoying x86 stuff so that you can focus on the more interesting parts of writing an OS.

I know this because for the final project my partner and I ported the OS to 64bit. Although the number of changes was not too large, we spent hours debugging low level x86_64 stuff. Although we learned a lot, I think it is a good idea the labs provide the boilerplate.

bmiranda··on NASA’s New Horizons Spacecraft Awakens for Pluto Encounter
Also don't forget Japan's Akatsuki space probe which will will attempt to insert itself in orbit around Venus in November.

It "missed" in 2010 due to an engine failure and had to wait 5 years for another attempt: http://en.wikipedia.org/wiki/Akatsuki_%28spacecraft%29

bmiranda··on Hyperloop
Rinon, you are correct. The Supreme Court (perhaps foolishly) decided that private to private transfer of land is permissible under eminent domain.

http://en.wikipedia.org/wiki/Kelo_v._City_of_New_London

bmiranda··on Kids can't use computers, and why it should worry you
The only thing I found annoying was his pet peeve about "the internet being down". I might tell someone that to get the idea across. Of course, I could say that "I was unable to establish a TCP/IP connection with the web server", but saying "the internet is down" is much simpler.

Then again, I correct people when they call the computer tower a "CPU" or "Hard Drive", so I'll give him the benefit of the doubt.

bmiranda··on NSA loophole allows warrantless search for US citizens' emails and phone calls
It's disheartening that despite the continual stream of information pouring in about the NSA the average citizen remains comparatively indifferent and the media and most representatives seem to be supportive of the NSA's activities.

That being said, I wouldn't go as far as to say the average American doesn't care, just that their reaction in light of these leaks is underwhelming. I don't believe that the slide towards total surveillance (or anything for that matter) is inevitable, but I would much appreciate confronting mass surveillance now as opposed to 10-20 years down the road.

bmiranda··on Letter from MIT President on Releasing Aaron Swartz Documents
http://tech.mit.edu/V133/N7/hoax.html
bmiranda··on Python.org Redesign Preview
This is an example of a how to do a great OSS website: http://git-scm.com/

Granted, it is a bit easier to make a succinct website for something like Git rather than the entire Python project.

bmiranda··on The Target Value for Bitcoin is $100K to $1M
Historic prices in USD for those interested:

http://bitcoincharts.com/charts/mtgoxUSD#tgSzm1g10zm2g25

bmiranda··on The Target Value for Bitcoin is $100K to $1M
Just checked MtGox, Bitcoin is now trading at $46... it was around $35 this time yesterday.

Things seem to be getting out of hand.

bmiranda··on Namecheap now officially accepts Bitcoin
The price of Bitcoin is currently hovering around 37 USD. I remember when Bitcoin was $2.00 after the first crash, I never expected it to rebound so quickly. Announcements such as Namecheap's lend credence to the current price, but I would not be surprised if a correction brought Bitcoin below $30.

Regardless, I am excited that there are more places to spend Bitcoin each and every day.

bmiranda··on Show HN: Multiplayer Snake in Go
In my first game we were both confused about which snake we were and ended up hitting the wall at the same time.
bmiranda··on Survey of MIT Students on their Stress
For me personally, most of the stress does come from being challenged academically.The professors pull no punches, and some of the classes are downright exhausting.

Although I appreciate being challenged, it can be disheartening whenever I observe the local coding guru / math major knocking out problems in a fraction of the time it takes me.

However, I believe that this student response best sums it up:

"I still believe it’s true that at MIT, students generally compete more against themselves than against each other."

Everyone simply wants to be the best that they can be.

- MIT Sophomore in EECS