2041
New
The latest blog posts to take off on Hacker News. 2,393 posts.
2042
Elsevier journals – some facts
Update: figures now in from Imperial. See below. Further update: figures in from Nottingham too. Further update: figures now in from Oxford. Final update: figures in from LSE. A little over two yea…
2043
Analysis of suspected MH370 pings recorded by Ocean Shield
So this is a bit of a deviation from my normal MATLAB oriented posts. In-fact MATLAB was not used once in this analysis! I've been followi...
2044
Neural Networks, Manifolds, and Topology
Recently, there’s been a great deal of excitement and interest in deep neural networks because they’ve achieved breakthrough results in areas such as computer vision. 1
2045
Evolutionary algorithm to find Quake III's fast inverse square hack with Python
Curiosity killed the cat I've always been amazed by early game developers. Unlike today, they had to bend and twist software to its extre...
2046
Why 'gallons per mile' is better than 'miles per gallon'
Why we should really be quoting fuel consumption figures as 'gallons per mile' and not 'miles per gallon'.
2047
0^0
Clever student: I know! $latex x^{0}$ = $latex x^{1-1}$ = $latex x^{1} x^{-1}$ = $latex \frac{x}{x}$ = $latex 1$. Now we just plug in x=0, and we see that zero to the zero is one! Cleverer …
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Why are roller coaster loops not circular?
Why are the loops on roller coasters never circular?
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New partition function record: p(10^20) computed
The partition function p ( n ) counts the number of partitions of n , i.e. the number of ways n can be written as a sum of positive integers when disregarding the order of the terms. For example, 4 has the five distinct partitions 4, 3+1, 2+2, 2+1+1, 1+1+1+1, so p (4) = 5. This week, I set a new record by computing…
2054
Overkilling the 8-queens Problem
Last night, a fellow Hacker Schooler challenged me to a running-time contest on the classic eight queens puzzle. Naturally, I pulled up my trusty …
2055
Reverse-Engineering Xkcd's 'Frequency'
About a week ago, Randall Munroe published Frequency , the 1331st entry in his xkcd webcomic series. Unlike most xkcd comics, it's animated — actually, 5-by-10 grid of animated GIFs. Each describes a scenario (e.g., "one birth," or "someone locks their keys in their care") and blinks at the scenario's purported…
2056
Levels of Excellence
Over on Google+, a computer scientist at McGill named Artem Kaznatcheev passed on this great description of what it’s like to learn math, written by someone who calls himself ‘man aft…
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The Firing Squad Problem
In 1957, John Myhill first posed an interesting problem that was closely related to computer programming, but did not require any related background to solve. Dubbed the "firing squad synchronization problem," the puzzle was passed along by word of mouth and first solved by Marvin Minsky and John McCarthy. However…
2060
How to compile with continuations
In terms of unreasonable effectiveness, the transformation to continuation-passing style (CPS) ranks with the Y combinator .
2061
How to Conquer Tensorphobia
A professor at Stanford once said, If you really want to impress your friends and confound your enemies, you can invoke tensor products… People run in terror from the $ \otimes$ symbol. He was explaining some aspects of multidimensional Fourier transforms, but this comment is only half in jest; people get confused by…
2062
Terry Tao on how to compute non-converging infinite sums (2010)
The Riemann zeta function $latex {\zeta(s)}&fg=000000$ is defined in the region $latex {\hbox{Re}(s)>1}&fg=000000$ by the absolutely convergent series $latex \displaystyle \zeta(s) = \su…
2063
The sum of all the positive integers is not -1/12
I haven't been blogging recently because my new startup is taking up all my time, but someone needs to stand up and say the emperor has no c...
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Dual_EC_DRBG backdoor: a proof of concept
Dual_EC_DRBG is an pseudo-random number generator promoted by NIST in NIST SP 800-90A and created by NSA. This algorithm is problematic because it has been made mandatory by the FIPS norm (and should be implemented in every FIPS approved software) and some vendors even promoted this algorithm as first source of…
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What are the 'real numbers', really?
The short, simple answer used in calculus courses is that a real number is a point on the number line . That's not the whole truth, but it is adequate for the needs of freshman calculus. The freshman calculus course (at most universities nowadays) follows the 17th century style of Newton and Leibniz, emphasizing…
2070
The Fallacy of Cracking Contests (1998)
In this issue: The Fallacy of Cracking Contests How to Recognize Plaintext News The Doghouse: Iomega Zip Disks Counterpane Systems News Final Report from the Commerce Department Technical Advisory Committee on Key Recovery Comments From Readers About "CRYPTO-GRAM"