Archive for quantum cryptograpy

stochastic magnetic bits, simulated annealing and Gibbs sampling

Posted in Statistics with tags , , , , , , , , , on October 17, 2019 by xi'an

A paper by Borders et al. in the 19 September issue of Nature offers an interesting mix of computing and electronics and optimisation. With two preparatory tribunes! One [rather overdone] on Feynman’s quest. As a possible alternative to quantum computers for creating probabilistic bits. And making machine learning (as an optimisation program) more efficient. And another one explaining more clearly what is in the paper. As well as the practical advantage of the approach over quantum computing. As for the paper itself, the part I understood about factorising an integer F via minimising the squared difference between a product of two integers and F and using simulated annealing sounded rather easy, while the part I did not about constructing a semi-conductor implementing this stochastic search sounded too technical (especially in the métro during rush hour). Even after checking the on-line supplementary material. Interestingly, the paper claims for higher efficiency thanks to asynchronicity than a regular Gibbs simulation of Boltzman machines, quoting Roberts and Sahu (1997) without further explanation and possibly out of context (as the latter is not concerned with optimisation).

the girl with the spider’s nest [book review]

Posted in Books with tags , , , , , , , , , , , , on June 12, 2016 by xi'an

“..the Millennium Trilogy was messier and more eccentric than much popular fiction, a genre that can lean towards standardisation. Lagercrantz’s continuation, while never formulaic, is a cleaner and tighter read than the originals…” The Guardian

“…while Mr. Lagercrantz never makes the N.S.A.’s involvement in the case Salander and Blomkvist are investigating remotely convincing, he writes with such assurance and velocity in the later portions of the book that he powers through these more dubious passages.” The New York Times

Millennium is a bit like chocolate addiction, when I carefully pack away the remains of a Lindt tablet, only to get back to it for another row half-an-hour later… The style of the series is rudimentary, the story is just implausible, the message is shaky, as explained in my earlier reviews, and still, still, I just got back from binge reading a new volume, even though it was written by another author. David Lagercrantz. Who also managed to write a biography of both Alan Turing and a (former Paris) footballer competing with Chuck Norris…

I had misgivings, to start with, about another author taking over the commercial massive success of the previous author (towards a further commercial massive success, apparently, to judge from the 7,575 customer reviews there!). With much less legitimacy (if any) than, say, Brandon Sanderson taking over Robert Jordan to complete the Wheel of Time. (Although this sequel is completely legit, since Stieg Larsson’s family controls his literary estate and hired David Lagercrantz.)  On the other hand, I do not have the highest respect for the literary qualities of the series, beyond inducing a remarkable crave for the next page that kept me awake part of both nights when I read The Girl with the Spider’s web. A feature that, in my opinion, relates to the essentially commercial nature of the product (and that is compounded by the mere £3.00 it cost me in a Coventry supermarket!).

Without getting into spoilers, the current story revolves around the complicated family tree of Lisbeth Salander, the endless fight of the Millennium editors against market forces, the murky waters of hacking and of intelligence companies, plus some lines about NSA’s Egotistical Giraffe, quantum computing, public-key encryption, and resolution by elliptic curve factorization. Story that remains as enjoyable as the previous volumes, even though it may be lacking in the psychology of the characters.  Given the extreme implausibility of the intelligence central plot, I am rather surprised at the very positive reviews found in the press, as shown by both quotes reproduced above…

One of the threads exploited in the book is the threat represented by super-intelligence, that is when AIs become much more intelligent than humans. This should ring a bell as this is the theme of Super-Intelligence, the book by Nick Bostrom I reviewed a few months ago. Although this volume of Millenium only broaches upon the topic, and while there is no reason to imagine a direct connection between both books, even though Lagercrantz may have read the popular book of a fellow Swede, I find the setting both amazing and so representative of the way the book ingratiates itself into the main computer culture memes.