Posts like this are why I love HN. I recently wrote a program to find anagrams of a given string (a Countdown solver if you live in the UK).
It includes a really naive method for generating all possible permutations of the string, but reading this post I can immediately see a far better way to do it.
That's my weekend taken care of! thanks to the poster and author.
There was a recent post about anagrams and the author just put all the letters in alphabetical order and then compared the words, which was more efficient than generating permutations.
I ran an anagram website in the 90s, and that was what we did. We stored word lists with a key of all their letters sorted. We then calculated anagram scores on demand because I couldn't work out a nice enough way to store those.
Forgive me if this is a silly question but when he talks about "beautiful solar-roof-with-battery", is he talking about car roofs or roofs of buildings?
An electric car with a solar roof that charges all day would be pretty cool.
I haven't figured it out, but my intuition is that the increased energy requirements of a tractor trailer mean that there isn't enough area there either.
Back of napkin, it looks like you get ~3*15 meters of roof which seems to translate to 10 kW of output under good conditions and then you need something like 150 kW to rumble up the highway.
Well trucks still have a lot of low hanging fruit for becoming more aerodynamic.
Plus you could use the sides of the trailer for some power too.
Finally even if 10kw can't power the truck. It could extend its range by some amount. Plus that's still a significant amount of power you don't need to buy. 2-3 rooftops worth?
Those improvements are presently not done because of cost. Grid electricity is a lot cheaper than diesel.
I guess electric trucks would still put a lot more effort into avoiding air resistance because of the lower energy per unit mass of batteries (the aerodynamic improvements can be pretty directly traded for either range or cargo capacity).
I think present day solar cells are a combination of too expensive and too heavy to bother with. That could change in the future.
I have thought the same thing -- that trucks could be more aerodynamic. So why aren't they? The economics of freight are such that any measurable improvement in fuel economy is worth a lot. Why do we not see super streamlined semis? Maybe there's some non-obvious reason? I don't know.
I think it already is pretty overcrowded and this has become a problem that NASA/ESA and others are thinking about. Here is a good ESA video on space debris:
In a way it's even more important. Apollo was an amazing achievement, but it wasn't set up to be sustainable. Spending billions just to beat the Russians doesn't last.
If you want to see more interesting space activity than a bunch of comsats, some probes, and the ISS, you need to make space a lot cheaper. That's been stagnant for a very long time, and what we saw today is the second step towards something that promises to cut the cost of space by an order or magnitude or more. We're finally seeing something that might make space something more like aviation, not just a bunch of national prestige projects with a handful of commercial uses.
If people are living on Mars in 50 years (which looks more and more likely now) then it'll be because of this, far more so than the legacy of Apollo.
Yes, that's what I meant. The first landing was a huge step, proving the whole crazy concept can work. This was another huge step, proving that the whole crazy concept can work out at sea, where it needs to happen most of the time.
The eventual goal is to have the car be able to open your garage door, exit, close your garage door, then drive to your location, stopping to charge itself at supercharger stations along the way.
The NYC to LA tweet implies the car would need fully autonomous driving capabilities to do so.
I wouldn't expect the autonomy package to have a huge impact on range. It takes a lot of energy to figure out where you are and navigate when you're looking at it from the context of a quad copter or what you can carry in your pocket but it's probably going to be pretty small compared to a Tesla's beastly 60+kWh battery. Even on the rolling cabinet I worked on[1] the motors took more power than the autonomy kit did.
I don't mean the range so much as it sounds like he could be hinting that the car will be capable of being fully autonomous. Considering the price point for the entry level version is ~35k, could we be about to see the first mass market self driving car?
I think it's very clear the Model 3 will be fully autonomous.
It has no cluster - no gauges of any kind in front of the driver, and only a tiny speed readout on the big screen in the center of the dash. In the Verge video a Tesla designer says that's production ready (not just alpha).
I won't be shocked if it doesn't have a steering wheel or pedals, or at least downplays them a lot.
It is diluted, indeed. We are poor and many, they are rich an few. It is much easier to maintain coherence between them than between us. They can use mass media and other channels to incite even more conflict and division between the poor to keep them from mounting a meaningful resistance.
I don't think a social change will happen on its own or by revolution, but rather there will be improvements in life quality for the poor as new technology such as the internet and smart phones are made available for the masses at low prices. The standard of living has improved in the last 100 years a lot for everyone, and this trend is going to continue in the future.
But the fact is we can't stop people cooking up nerve gas and anthrax in their garages if they want to. Just like we can't stop them building their own encrypted apps. Banning it won't stop a determined group.
The IRA were known to recruit top stem students from universities in Ireland during their campaign to make bombs. Surely an entity as large and as well financed and ISIS would have little trouble finding bright young engineers & technologists sympathetic to their cause to simply build their own encrypted services? And then so much for the spooks 'backdoors'
The tactic you're suggesting has been tried before (the software was called Asrar, I think). It doesn't work well for them, for a couple of reasons:
1) Custom terrorist software is no easier to use than something more mainstream like PGP, but is a lot more incriminating if you're found to be using it.
2) Is it really made by fellow jihadis? Or is it a backdoored plant by western intelligence? How can you know?
The latter question is a bigger issue than you'd expect. Terrorists don't like to helpfully announce their real names and backgrounds on their websites, so the provenance of jihadi software is frequently unknown. It just sort of floats around on the internet. So it can be much harder to trust than just a plain old copy of PGP.
You might think that IS can solve these problems because it's bigger and more organised than a group like al-Qaeda. But it's not like IS has an official website with a nice SSL certificate and a big download button (CA's will generally not sell to sanctioned entities). They use networks of ad hoc and quickly suspended twitter accounts to communicate, and apparently, Telegram. So for them to distribute custom crypto software wouldn't be easy.
> Surely an entity as large and as well financed and ISIS would have little trouble finding bright young engineers & technologists sympathetic to their cause to simply build their own encrypted services?
You wouldn't even need the brightest engineers. In fact so many encryption algorithms have been opened sourced and / or in library form for so long that it's easy for practically any developer to do.
Just having a library that does something doesn't magically bring security. The issue is, engineer still needs to know a lot of stuff (or strictly conform to the instructions) to use the thing correctly. There are too many ways to screw the thing up without even knowing it.
So, if the thing's to slap some nice GUI upon an existing library that implements the security bits, then almost no knowledge's required. But if one has a library full of primitives but still has to combine them in a meaningful way - it's a damned minefield.
That statement shows you haven't spent any time researching the security of secure messaging solutions. Or security software in general. Virtually all of them had protocol or implementation flaws with most having flaws so severe that cryptographers and top programmers saw fit to write books detailing how to do it right.
Books most people making "private" apps still haven't read. ;)
Well maybe i'm transmitting my memory dump or generating random traffic / sprouting entropy. Or everything is transmitted with mime types? Even so it makes no sense as even the most basic steganography would provide plausible deniability. I mean encrypted data is indistinguishable from noise...
