While it's nice to think that airlines can just rely on regulators to tell them which flight paths might be unsafe, the reality is that there's no international regulatory agency governing acceptable flight paths. There's a regulatory agency for every country and while one country might have stringent safety measures, another might not.
In such an environment it seems naive for an airlines to not include the safety of the flight path in their calculations. If all civilian flights below 32K feet are forbidden by the Ukrainian authorities, that doesn't automatically mean that flying just 1000 feet above would be safe. Also while other airlines are guilty of flying over war zones too, that doesn't mean Malaysian airlines is not.
It doesn't follow automatically, but given the specific limit, one would assume that it was deliberately chosen and includes an error margin. There's nothing wrong with flying at their assigned altitude, which was above the limit.
In aviation, you have to manage risks, you cannot avoid them entirely. For example, there are different levels of redundancy, depending on how critical a system is. There may be two, three or maybe four units, but there surely aren't 25 units of even the most critical equipment - the plane would be too heavy to take off. At some point, you have to decide what the acceptable risk is, and go with that. I think your argument has a strong hindsight bias.
But with no legal power of enforcement I'm guessing? I mean an airlines can always choose to follow the directives of agencies from other countries that have more stringent standards.
I guess what I'm trying to get at is that there should be definitely increased public pressure on airlines to include flight safety in their calculations. Or atleast not fly over active war zones..
Yes, NP-complete is a subset of NP-hard. Grandparent states that NP-completeness only applies to decision problems (which is correct), but seems to think that NP-hardness applies to optimization problems (which is incorrect; NP-hard too is a class of decision problems).
Bill Gates and Zuckerberg didn't leave Harvard permanently though. They took a leave of absence which means they'd the option to come back if things went south. Also both (and Gates especially) were from quite well off families.
What? The modern definition of pseudorandomness (https://en.wikipedia.org/wiki/Pseudorandomness#Pseudorandomn...) was figured out in the 80s through the works of Blum, Goldwasser, Micali, Goldreich, etc. and is not hand-wavy at all. It's pretty rigorous and reliable.
You are 100% mistaken that this implies we had a good definition of random sequences before Knuth. In the article you link, they discuss the uniform distribution, but any distribution (and the modern notion of probability in general) absolutely depends on a mathematically precise notion of random sequences.
If you don't believe me, read the chapter. Early probability theorists (e.g., von Mises, Kolmogorov) literally started thinking about randomness in order to define probability.
EDIT: And, I don't suppose it's worth pointing out that pseudorandomness is not at all the same thing as randomness. The fact that you seem to use them interchangeably is not a good sign IMHO.
I skimmed through the extract presented (didn't have time to go into detail) but I don't see a formal definition of any kind presented in the extract. Could you point me to where it is? And if it's not in the extract, then could you quote it here?
Pseudorandomness is not the same thing as randomness but most algorithms today work on pseudorandom numbers so the concept is important. My impression was that that's what you were referring to.
PS :- FYI I didn't downvote your comment. Actually upvoted as your post made me discover some new math (various notions of randomness by kolmogorov, von mises, martin-lof) :)
So, the excerpt here is chapter 3, section 1. The actual definition happens in chapter 3 section 5 ("What Is a Random Sequence?"). I have the book at home, though, so I can't quote it here. Sorry. But the intuition is, if you have an infinite sequence of random numbers, then the numbers in all infinite subsequences should be equidistributed. So, like, if you a stream of random 0's and 1's, then if you pick only every other number, the 0's and 1's have to be equiprobable, and if you pick every third number, they still have to be equiprobable, etc. This is slightly wrong, but it's on the right track to the actual definition.
re: Pseudorandomness, the point of pseudorandomness is the following.
1. A lot of algorithms use randomness to make pathologically bad cases extremely unlikely. For example, choosing a random pivot in quicksort makes the worst case very unlikely.
2. But in a lot of cases, this leads to huge amounts of space consumption. For example, most frequency moment estimations involve a matrix of random numbers. So if you're getting those numbers from a "truly random" source, then you have to store the entire matrix, which can be huge.
3. So, a better solution is to use a pseudorandom number generator! That way you can store a seed of s bits, and do something clever, like deterministically re-generate the matrix as you need it, rather than storing it outright.
Notice though, that this is not independent of the notion of randomness! In fact they are quite intimately tied together.
Your definition relies on the notion of probability though. So I'm not sure why you seemingly view Knuth's work as more fundamental than Kolmogorov's, etc.
What's the sketch of the trick? I can define randomness by appealing to some of the same basic theory used to develop probability, but it's not really independent despite looking that way from the outside. Does Knuth do this uniquely?
In my experience Java is usually at most 50% worse than C++. This is only the case though when I write Java with minimal use of objects (so no generics for instance). Also this is in comparison to C++ code that's not too micro-optimized (so mostly idiomatic) and that is not compiled via profile-guided optimization for instance.
ACARS is what the article seems to be saying is how they know. Last ACARS transmission was 1:07 am. Any pilots here who know whether ACARS actually transmits FMS information?
Edit: And if the report is correct and ACARS sent the information all along, why in the world did it take them 10 DAYS to find this out?
According to wikipedia ACARS can include FMS info. It is odd that this has taken 10 days and even now is kind of leaked by "an American official". You'd think they would have checked that stuff straight away and made it at least semi public so aircraft experts could check it out.
Unless you're trying to commit suicide. But then why would fly northwards instead of southwards if you want to commit suicide? I've a hard time believing the 5000 ft statement. But if it's true, then well, damn.
That's only for the Andaman and Nicobar islands though which are very far from the mainland. I'd be surprised if there's no 24/7 radar for the mainland.
In such an environment it seems naive for an airlines to not include the safety of the flight path in their calculations. If all civilian flights below 32K feet are forbidden by the Ukrainian authorities, that doesn't automatically mean that flying just 1000 feet above would be safe. Also while other airlines are guilty of flying over war zones too, that doesn't mean Malaysian airlines is not.