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Sunday, Oct 21, 2007 - 20:52 SGT
Posted By: Gilbert

Just Justice

Just realised that the first sentence of my last three posts all contained the word, "just". I have really got to discover more variety in my openings.

Taking a breather before re-learning how to edit videos for MNO1001, and after raising my first Seneschal in Dragon Court (account Edmund_Chong created on 17 July 2007 according to my Gmail archives, so it indeed takes about three months), I decided to just exploit that "just" piece of trivia and create a weakly punny themed post - and what cooler thing than to append ice to it?

Pedo Justice

We begin with the Canadian pedophile suspect Christopher Paul Neil, 32, who was caught in Thailand a few days back. Apparently, a big factor in his arrest was that police managed to "unswirl" a distorted image of himself that he posted online, secure in his untrackable anonymity.

Apparently he regarded himself as pretty computer savvy, but unfortunately for himself the "swirl" function isn't exactly suited to obscuring data. While the German experts are yet to reveal their "latest high tech tools", I daresay they needed little more than a copy of Photoshop with its built-in Twirl filter, and a bit of guesswork:

Photoshop for Great Justice (3D Head Image Source)

The key to the failure of swirling is that it in practice approximates a one-to-one (two-way) function - that is, knowing the central point where the swirl is applied and the degree of the swirl, one can map a pixel on the original image to a pixel on the swirled image pretty well. Then, to recover the original image, it remains only to reverse the function. In contrast, functions for encryption purposes generally should be one-way.

But when obscuring a photo, we don't really want to recover the data as in encryption applications anyway - in fact, we can simply discard enough data such that there is insufficient data to reconstruct the original at all, as proven by information theory. An example is the Mosaic filter, which divides the image into blocks of a given width, then averages the colour within each of those blocks and sets that as the colour of the whole block itself:


I've used this here often enough

Intuitively, this mosaic function is definitely not one-to-one. Consider a 2x2 block with just four pixels, and let their colour values be say 0 (black), 0, 255 (white) and 255. Averaged, they give about 128, which is a medium gray. Now, imagine one tries to reconstruct the original block from this data. All we know is the average value of the colours in the block, and thus 0, 0, 255, 255 is a possibility. However, 1, 1, 254, 254 is also a possibility, as are approximately 16 million other combinations of pixel data - and this is just a grayscale four-pixel block.

More importantly, even if all combinations could be enumerated, there is still no indication of which of them is the correct one. Put another way, if one could produce all possible combinations, the original face would surely be reproduced - but so would countless numbers of other incorrect faces, with no way to discern among them which one is the right one. This is in fact the very logic behind the unbreakable one-time pad encryption scheme.

Of course, as with the case of flawed nonrandom keys for one-time pads, an improper execution of the Mosaic filter (such as extremely small blocks) may make it remotely possible for some useful data to be recovered, but I wouldn't bet on it.

Gay Justice

Section 377a of the Singapore Penal Code, which prohibits male-on-male intercourse (note: hot lesbians excluded!), has drawn quite some attention recently. A website has been set up to argue for its repealment, with a parallel website aimed towards keeping it being created in response.

Personally, I have precious little interest in what consenting individuals do to each other in private (www.idunreallycareabout377a.com, anyone?), but the arguments presented are rather interesting. Keep377a.com cuts straight to the bone by declaring that "almost 70% of Singaporeans expressed negative attitudes towards lesbians and gay men", implying that the majority should win out - we are a democracy after all, no? Repeal377a.com in contrast exhorts readers to "act towards change for the good of all Singaporeans regardless of gender, race, religion or sexual orientation".

Me, I just say society accepts whatever it will.

Suppose now that society regards a twelve year-old as an adult. This isn't really that farfetched as the age of consent was thereabouts just a century or two ago, only rising closer to 18 relatively recently. It has often been ironically observed that in many countries, a 16 year-old is old enough to die honourably for his country as a soldier, but not old enough to drink, watch certain movies or engage in not-so-clean fun with the opposite gender.

Indeed, is there any stone-clad reason that twelve year-olds should not be regarded as adults? If mental maturity is the key, hitting a certain age is no guarantee of that, and humans appear to be getting smarter; It may also be that teens behave immaturely because society deems them as unworthy of being adult yet, and not vice versa. Certainly in many cultures it would be natural for a 12 year-old to undergo initiation and be recognized as a man. California is asking itself this question, with a proposal for 16 year-olds to have half a vote, and 14 year-olds a quarter. It seems difficult to slam any society that does pass this as a law.

But what is the implication of this, combined with gay rights? Suddenly, Christopher Paul Neil is not a scum-of-the-earth pedophile suspect, but a fine and upstanding citizen, assuming that he does not coerce the kids unduly but instead strikes some agreement with them. This is not a veiled attack upon gay rights, mind - taken alone, the reduction in the age of consent would lead to it being legal for grown men to "do it" with 13 year-old girls, which it has to be again stated was not all that uncommon for most of human history. Man-to-boy pederasty was an institution among the ancient Greeks, Romans, Celts and Persians, and more recently among the Japanese samurai. Was Neil just born into the wrong age?

The quote was originally used in reference to intellectual property, but I say it applies similarly to equality of rights too - "it is the wrong verb about the wrong noun". Take the case of freedom of religious expression. Say, if a widely followed religion commands its followers to fully hide their faces, would it be fair for service-oriented jobs to bar them if it affects their ability to relate to customers? Or are the customers at fault for being unfairly discriminative, and it is they who should "open their minds"?

Another example: Let us say that an employer has experience with people from a certain region/race/religion/social group, and the facts are that out of every ten such people he has employed, nine turn out to have qualities unsuited to work despite their qualifications. If he does not discriminate, he thus calculates that it is likely his business will go bankrupt soon, but if he does discriminate then he would be unfair towards those people who are good workers. It is completely unacceptable to say so, though, as Nobel laureate James Watson found out when he claimed that "black people are generally less intelligent", and that he was "...inherently gloomy about the prospect of Africa" because "all our social policies are based on the fact that their intelligence is the same as ours - whereas all the testing says not really.".

The strange thing is that if he made the statement that he had proven that "black people are generally stronger and faster" or "black people are generally better at basketball", probably few would have batted an eyelid. Even accounting for socioeconomic factors, given that sports is a respected and lucrative pursuit in the USA, the preponderance of black athletes in the top leagues would appear to strongly suggest that. Yet, for daring to suggest that "white people are generally smarter", he gets thrown out on his ass. Would he have fared better if he had dispensed with any interpretation and just said something along the lines of "research data shows that... Race XXX generally scores higher/lower on I.Q. tests"? Probably not by much, even if he added the disclaimer that I.Q. tests may at most measure one particular facet of intelligence.

It's a complicated world.

Exam Justice

Another year, another PSLE season, and another batch of parents raving over the unfairness of it all. Unfortunately, the nature of exams and indeed any competitive measure means that not all can be satisfied, for some will be "ahead" and other "behind". Leaving aside the usual knocks that academic performance is overemphasized, is it fair to test concepts from outside the syllabus, as the Math paper was accused of?

I would say, why not? - if the out-of-syllabus content is well-balanced (i.e. counts for relatively little). A little extra would go towards identifying the very best, and getting about 90% without that little extra isn't going to kill. If that's "murder", then the student's going to have a very sad life ahead. Parents have to do their part, though, and recognize that absolute scores don't mean anything. Getting 50% is wonderful if that's the top score, while getting 80% may turn out to be just average.

Let us look at a 5-mark question for this year:

6/14 of the chairs in a hall are in rows of 13. Half of the chairs are in rows of 7. There are 112 more chairs in rows of 7. The rest of the chairs are stacked up. Find the total number of chairs.

Throwing in the "rows of 13" and "rows of 7" designations as red herrings may have been a bit cruel, methinks. Actually, all that is required is to note that 1/14 of the total number of chairs is 112 chairs. Presto, the total number of chairs is 112*14=1568. My guess is that if the question were reworded as 6/14 of the chairs are blue, half are black, the rest are red and there are 112 more black chairs than blue, quite a few more students would be able to do it. Worth an experiment someday?

Legal Fees Justice

Little guy wins for once in this well-publicized case. Don't take this as the norm, however.

Not Justice

(Totally random stuff) The Japanese have come up with an original way to hide from crooks - transform into a vending machine! There's a crazy cute fire hydrant version for kids, which hopefully comes with the warning "Please do not use in presence of dogs". Well, the Japanese have always been kings of wacky inventions.

Two-second T-shirt folding too.



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2 comments

anonymous said...
How can your chairs be in rows of 13 when it is clear that the number of chairs is not a multiple of 13?

The question is flawed


October 24, 2007 - 15:14 SGT     
gilbert said...
Hmm, say if you have 15 chairs and are asked to arrange them in rows of 13, i think one row of 13 and one row containing the remainder of two would suffice, just a thought. Some poor students may have indeed gotten caught up in this though...


October 24, 2007 - 22:39 SGT     

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