## Misc

 LA home Computing  Misc.   U.rankings   Events   1984
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Eugene "Kaspersky, head of security firm Kaspersky labs, revealed at the Canberra Press Club 2013 ... that before the ISS switched from Windows XP to Linux computers, Russian cosmonauts managed to carry infected USB storage devices aboard the station spreading computer viruses to the connected computers. ... In May, the United Space Alliance, which oversees the running of the ISS in orbit, migrated all the computer systems related to the ISS over to Linux for security, stability and reliability reasons." -- The G. [www][12/11/2013]; see uBend [www][8/11/2013] (@ 17:57+).

1932 Brave New World, 1949 '1984', 1990s Great Firewall of China, 2010+ Wikileaks, 2013 Prism etc. (NSA, awareness of).

A case of 2 × 222 :  A data-set, D, consists of N pairs. A pair contains two binary (boolean) variables, (X, Y).
 Y T D'scases p=#(T,T) q=#(T,F) r=#(F,T) s=#(F,F)
Encode the data-set using two different methods. Note that each method can take advantage of positive or negative correlation between X and Y (dare one say of causality, X→Y?).
(i) Encode the data under a 4-state distribution, {1:(T,T), 2:(T,F), 3:(F,T), 4:(F,F)}:
pr1(D) = p! q! r! s! 3! / (N+3)!     (code_length1 = -log2 pr1 bits.)
(ii) Encode X as a 2-state distribution, and Y as one of two 2-states, one for each case of X:
pr2(D) = {v! w! / (N+1)!} {p! q! / (v+1)!} {r! s! / (w+1)!} = p! q! r! s! / {(N+1)! (v+1) (w+1)}
So,  pr1 / pr2 = 3! (v+1) (w+1) / ((N+2) (N+3)) < 6 / 4, and  pr2 / pr1 < (N+3) / 6.
If v ≈ w, method (i) has the shorter code length, about log21.5 less than that of method (ii) -- at most just a fraction of a bit less for the entire data-set. But if v/N→1 say, w/N→0, then pr2 > pr1, and method (ii)'s code length is up to roughly log2N bits shorter for the data-set (unbounded per data set, but < log2(N)/N per datum). (Of course, similar considerations also apply to (ii') Y; (X|Y).)
So why are the probabilities in (i) and (ii) different? Method (i) assumes a uniform prior over the 4-state's three parameters, ⟨pr((T,T)), pr((T,F)), pr((F,T))⟩. Method (ii) assumes a uniform prior over the parameter, pr(X=T), of X's 2-state, and a uniform prior on the parameter of each of Y's 2-states, pr(Y=T|X=T) and pr(Y=T|X=F). These are subtly different assumptions.
(Recall that the adaptive code (Boulton & Wallace [1969], [MML]) transmits a data-set of k-state values, [1..k]N, in log2((#1! ... #k! (k-1)!) / (N+k-1)!) bits. It is optimal for a uniform prior; for a non-uniform prior initialise the "counters" to values other than one.)

From observation at the local lake, about half of the birds are coots, 30% are ducks, and 20% are swans.
Most ducks and swans, say 90%, have been seen to waddle. No coot has been seen to waddle (but maybe one could), pr(B waddles|B is a coot) = 0.1, say.
Most ducks, say 90%, have been heard to quack. No coot has been heard quacking, pr(B quacks |B is a coot) = 0.1, say. Similarly for swans.
Someone reports that a certain bird, X, was observed to waddle and to quack. What species, S, is X?
pr(B is a S|B waddles & B quacks) ∝ pr(B is a S) . pr(B waddles|B is a S) . pr(B quacks|B is a S),
pr(X is a coot) ∝ 0.5 × 0.1 × 0.1 = 0.005,
pr(X is a duck) ∝ 0.3 × 0.9 × 0.9 = 0.243,
pr(X is a swan) ∝ 0.2 × 0.9 × 0.1 = 0.018,
total  0.005 + 0.243 + 0.018 = 0.266.
pr(X is a duck | X waddles, X quacks) = 0.243 / 0.266 = 0.91 -- if it walks like a duck and talks like a duck it is (probably) a duck, according to naive Bayes. (Bayes because of the use of Bayes's theorem, and naive because waddling and quacking are assumed to be independent.)

The Federal Court of .au ruled [FCA 65] against 'Cancer Voices [.au],' and for "US-based company Myriad Genetics and Melbourne-based Genetic Technologies, over the patent on a breast and ovarian cancer gene known as BRCA1 ... Justice John Nicholas ruled that the gene could be patented, as it had been isolated completely separately from the human body.", -- [abc][15/2/2013]. Also see FCA65@austlii [www][2/2013].  A pity, I think.
13 June 2013: Good news and worse news? "... we hold that a naturally occurring DNA segment is a product of nature and not patent eligible merely because it has been isolated, but that cDNA [complementary DNA] is patent eligible because it is not naturally occurring. ..." -- Justice Clarence Thomas, [supremecourt.gov][13/6/2013] (No. 12-398). (Also see [bbc], [the G.].)

The International Table Soccer Federation [ITSF] (i.e., foosball) has [rules] and videos of past championships [www] online.

Have finally disentangled the mathematics in the various meandering explanations of the von Mises - Fisher probability distribution on directions in RD and of MML-ing it.

In some cultures sons are valued more than daughters and the male:female sex ratio at birth is much higher than one (ultra-sound, abortion, ...); the ratio is reported to be as high as 1.19:1 in China (WDB). Fisher (1930) showed that natural selection drives the ratio to 1:1 : Every child has one mother and one father. If there is an excess of males, a male has a lower chance of having children than a female. (And v.v. if there is an excess of females.) So, someone having a daughter in such a culture is more likely to have grandchildren than someone having a son. A tendency to have daughters is being selected for. Just give nature time.
(Note, selection drives the ratio at reproductive age to 1:1. The argument does not hold for all species, e.g., where females have multiple young, over time, after a single mating, say. Search for [sex ratio biology] in the [Bib].)

The alien computer design in A for Andromeda (1961) still looks more than a match for a human in terms of neuron numbers, but not in synapses; there again, there's the matter of speed.

The stable marriage problem featured in the 2012 Nobel prize for Economics.

Dilbert is a documentary.

The good old Iterated Prisoners' Dilemma (IPD).

Enumerating all sequences of n pairs of matched brackets is equivalent to generating rooted, ordered, k-ary trees.

The Jacobi algorithm finds Eigen things of a real, symmetric matrix.

I really wish I had invented the Burrows Wheeler transform, in which case it would not be known as the BWT.
www:
 The C++ Cookbook mastering the language

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