oconnor663
Joined 14 years ago
Karma
7,579
Submissions
1,651
Member since
Sep 4
[ my public key: https://keybase.io/oconnor663; my proof: https://keybase.io/oconnor663/sigs/6u7ycNDOZvuO8qNrg69nGayUCyATOnCNq6H9tBV0BsM ]
View on Hacker NewsRecent submissions
Comment · 13 days ago
> That's identical to every mechanization before it.
Steam engines aren't very good at designing steam engines. I think this time will be different.
Comment · 18 days ago
Spending time in Japan was how I learned that I don't want to live without a clothes dryer.
Comment · 18 days ago
If you deal mainly with small-to-medium size Python programs, which is probably the norm, that makes sense to me. But if you have a large Python application, or if you own a library API that might have a lot of callers, typecheckers catch sooo many mistakes.
Comment · 18 days ago
https://github.com/JelleZijlstra/unsoundness is also a great collection of Python type system holes. In these cases, it's mostly deliberate design decisions, not bugs. The unfortunate fact is that a fully sound Python type system would be a pain to use.
Comment · 1 month ago
Comment · 1 month ago
> do not consider yourself a contributor to humankind
Good lord. You could apply the same logic to any taxpaying resident of any country whose government is doing something bad. There's some truth to it, it's worth bearing in mind, but it's also the very definition of an Isolated Demand for Rigor.
Comment · 1 month ago
"A Blank on the Map" is an incredible documentary about this sort of contact, though 40 years later. Here's an un-paywalled link: https://www.dailymotion.com/video/xsynjb
Comment · 2 months ago
I don't know anything about pharma, but having worked in tech and had my share of patent lawyer meetings, it sure doesn't seem like software patents are necessary at all. That said, a patent system has a lot of free parameters that you can dial to reduce the cost. At the silly limit, if patents were only good for 24 hours, the cost to society would be ~zero (though also the benefit would be zero), so it's hard to call that "evil" in the sense of definitely causing a lot of harm. The question becomes whether/when you can set all the free parameters to something worth having.
Comment · 2 months ago
> To change those percentages to 45% and 55%
This seems like a fundamental misunderstanding of how this sort of watermarking works. (Either that, or I have a fundamental misunderstanding of how it works lol.) It doesn't change the probability distribution of the next token at all. If you were getting XYZ 48% of the time before, you're still getting XYZ 48% of the time. What's changed is where the random numbers come from. But as far as you're concerned, there's just as random as they were before, just like an encrypted message is indistinguishable from random bytes if you don't know the key.
Comment · 2 months ago
If the problem is that the temperature is too low for the cut, you can just use a higher temp?
Comment · 5 months ago
Several air launch systems have been tried, with limited but non-zero commercial success. The altitude and speed you get from the plane is very small compared to the total work the rocket needs to do, so the benefit in terms of "the rocket can be smaller" is minimal. The main benefit in practice has been launching from ~wherever you like, since regular fixed launch sites usually have strict limits about the direction you have to fly to avoid people. But the economics of reusability are pushing rockets to get bigger, and no air launch system can fly anything nearly as big as a Falcon 9, much less a Starship + Super Heavy. Other scattered problems:
- Hanging under-wing is a totally different set of forces than standing vertically, especially for a big rocket with thin walls. You're more like a bridge than a tower, or rather like a bridge one moment and then a tower the next. You need reinforcement for that, which makes the vehicle heavier.
- Modern reusable rockets do quick "load and go" filling to keep their propellant as cold and dense as possible. You can't do that if you need to fuel on the ground and then hang off an airplane for ~an hour while it climbs.
Comment · 5 months ago
You can see a similar effect after the explosion at the end of last week's Starship test flight. If you look at where the flames are coming out after the first fireball clears, it kind of pancakes under its own weight there: https://www.youtube.com/live/Zi2SU98BAD8?t=5735s
Comment · 5 months ago
The vehicle is designed to hold all that fuel, plus whatever payload it carries on top, but it's not designed to have heavy loads attached to it in any other way. Rockets are so intensely optimized for weight that sometimes they're barely strong enough to stand upright if you fuel them the wrong way: https://www.youtube.com/watch?v=imkdz63agHY.
Comment · 5 months ago
https://web.archive.org/web/20120503175355/https://www.nasa....
> The percent propellant has huge implications on the ease of fabrication and robustness in achieving the engineering design (and cost). If a vehicle is less than 10% propellant, it is typically made from billets of steel. Changes to its structure are readily done without engineering analysis; you simple weld on another hunk of steel to reinforce the frame according to what your intuition might say. I can easily overload my ¾ ton pickup by a factor of two. It might be moving slowly but it is hauling the load.
> Once the vehicles become airborne, the engineering becomes more serious. Light weight structures made of aluminum, magnesium, titanium, epoxy-graphite composites are the norm. To alter the structure takes significant engineering; one does not simply weld on another chunk to your airframe if you want to live (or drill a hole through some convenient section). These vehicles cannot operate far from their designed limits; overloading an airplane by a factor of two results in disaster. Even though these vehicles are 30 to 40% propellant (60 to 70% structure and payload), there is room for engineering to comfortably operate thus there is a robust, safe, and cost effective aviation industry.
> Rockets at 85% propellant and 15% structure and payload are on the extreme edge of our engineering ability to even fabricate (and to pay for!). They require constant engineering to keep flying. The seemingly smallest modifications require monumental analysis and testing of prototypes in vacuum chambers, shaker tables, and sometimes test launches in desert regions. Typical margins in structural design are 40%. Often, testing and analysis are only taken to 10% above the designed limit. For a Space Shuttle launch, 3 g’s are the designed limit of acceleration. The stack has been certified (meaning tested to the point that we know it will keep working) to 3.3 g’s. This operation has a 10% envelope for error. Imagine driving your car at 60 mph and then drifting to 66 mph, only to have your car self-destruct. This is life riding rockets, compliments of the rocket equation.