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So, I was teaching (`demonstrating') in a practical earlier. One of the things we try to teach the students is, when doing a calculation, never to substitute actual numbers in to an equation until the last line, when you want to get a number out. Work in symbols until the very end. Otherwise you'll come unstuck. Etc. Etc. I'm sure you know all this.
Anyway, one of the students asked me why their calculation wasn't giving the correct answer. It turned out that they'd mixed up a quantity Z = 150 with another quantity whose value was 80. When I pointed this out, the student scratched out Z, and started to write in ``80''. Then realised that this was verboten, scratched out ``80'', and wondered what to write, since the question sheet didn't define any symbol for the quantity which was equal to 80. After a moment, inspiration arrived. The student wrote Z80.
There's a lesson here, but from the above it's pretty obvious that I'm not qualified to teach it.
Nick Barlow is running a sweepstake on the results of today's Conservative Party confidence vote. (You can also see the bets which have been placed.) I thought I'd enter, just for fun. Of course, I don't actually know anything about the inner workings of the Conservative Party, but rather than guessing blind I looked up the price that spread betting outfit IG Index are quoting (or, rather, their IG Sport subsidiary).
(This is a common approach to predicting the future which is oddly compelling -- to the naive. The argument is that if you want to predict some variable x in the future, you invent a security which will pay off according to the future value of x. Establish a market in this security, so that its current price is y. Now people who believe that x will be larger than y have an incentive to buy the security, increasing y. Those who believe that x will be smaller than y will sell their holdings, or perhaps sell the security short, if the market is sufficiently sophisticated. In equilibrium, y = x, so y can be used to predict x. This is fine if the traders in the market actually know about the future value of the variable x. If they don't, all bets are off. Spread betting is a fairly pure implementation of this idea; the `spread' is the difference between the selling and buying prices of the security and is there to ensure that the bookie makes a profit; DARPA's ill-fated Policy Analysis Market was another example, intended to predict acts of terrorism. I have no idea how effective the spread betting market will be in predicting the outcome of the Conservative Party's vote. In particular, to be accurate, members of the Party or their close confidants would have to be participating in the market, since they're the only people with the relevant information. Anyway....)
Last night, IG Index was offering a spread of 61--66 votes in favour of keeping Mr. Duncan Smith. This morning the spread was 55--60 -- i.e., overnight, their customers' opinion of his chances had declined. I thought it would be quite fun to monitor the price IG were offering and see how it changed during the day. Here's the plot, up to around 14:45 this afternoon: (note that I've only plotted the spread when it changed)
Sadly, at around 14:45 today, the market for this even was removed from the IG Sport web site. Indeed, for a time, their entire web site was offline; now, a request for the prices -- linked to from their front page -- gives,
The information you have requested is not currently available. Please try again later.
Those who are adept at spotting conspiracy theories may recall that IG's chairman, Stuart Wheeler, is a major donor to the Conservative Party... who also might like to claim some credit for triggering the confidence vote. Equally, it could just be a web site fuckup. I note that Blue Square, originally the fixed-odds arm of IG, are still offering odds on various possibilities for a new Tory leader. Of course, Blue Square aren't part of IG any more.
In other news, William Hill have been intermittently withdrawing their bets on the same set of hypothetical leadership contenders. Their slate for the leadership disappeared completely this afternoon. Betting doesn't seem to have been very active, and I note that the odds differ markedly between Blue Square and William Hill:
(I should also say that, although there's a temptation among those who have no ambition to see the Conservative Party form a future government to regard its present tribulations as a source of cheap entertainment, it would be a little sad if internal injuries left the party unable to oppose any of the offensive things that our Dear Leader proposes for the next Parliament. Equally, the idea of Michael Howard as Prime Minister fills me with horror, which makes the second of the above plots slightly concerning. I gather that, should Mr. Duncan Smith lose the confidence vote, we should expect to see some sort of stitch-up among the leading contenders so that the vote will not have to be put to the entire membership, a process which might paralyse the party for months. Ho-hum.)
(Actually, I have more interesting things to talk about than this, but not the energy to write them down right now. So you'll have to take that first bit on trust.)
A letter to Barclaycard:
Dear Gary Hoffman,
I am writing to draw your attention to a serious problem in Barclaycard's procedures relating to changes-of-address which has caused me inconvenience and leads to a risk of fraud against me and other cardholders.
I have my Barclaycard bills and other correspondence delivered to my family's home in London, whence it is forwarded to me at my current home address. I take this precaution with Barclaycard and other financial institutions since such companies are often poor at updating address details for their customers, and since my address has changed fairly regularly over the last few years and can be expected to continue to do so over the next few years, it would be foolish to expose myself to the risk that any of the companies with which I do business would foul up a change-of-address.
Recently Royal Mail delivered a redirected Barclaycard statement to Barclaycard, rather than to me. As you will be aware, Consignia isn't exactly the most competent of organisations, and such errors sometimes happen.
According to your customer service staff, Barclaycard interpreted this as an instruction to change my billing address, without ever consulting me. Apparently this is your `policy'.
Comment: observe how this justifies my concern about the correct processing of change-of-address information, though naturally in a way which has caused me the greatest possible inconvenience.
To change the address back (to that given at the top of this letter), I had to give all sorts of `security' details: my birthday (or `six digit pass code' as your telephone answering machine calls it before helpfully explaining what it really means), the card's expiry date, and the CVV2 check digits on the back of the card.
Note the contradiction. Anybody can have my Barclaycard mail -- including, for instance, future cards and PINs -- delivered to their own address by intercepting a single piece of my mail from Barclaycard, and sending it to Barclaycard with a new address on it. But I, as the cardholder, have to go through a complicated -- ostensibly `secure' -- procedure to have the problem fixed.
Comment: this is backwards. It should not be easier for an arbitrary third party to change the address details held by Barclaycard for my account than it is for me to do so.
Barclaycard did not notify me that it had changed my contact address. Your service staff told me that such a notification should have been sent to me, but none was received. Obviously this part of your procedure is -- if followed at all -- not reliable.
Comment: this is as expected, since your notification procedure involves sending a letter to a someone about whose address you must a priori be uncertain. In order to do this properly, you need to contact the customer by some other means, for instance telephone.
This failure reliably to confirm changes-of-address means that, if my contact address had been changed by a fraudster, I would not know about it until it was too late. Indeed, such a criminal could then ring Barclaycard, report the card as stolen, and get a new one delivered to their own address. And, not knowing the new cardholder address, I might not be able to `authenticate' myself to Barclaycard's computer system to find out what had happened.
Comment: this is stupid.
- Please ensure that any future changes of address on my account must be confirmed with me before being made. I have already asked your customer service staff to make such a note on my account, but would like confirmation that this will be honoured.
- As I describe above, your procedures for changes-of-address expose me to a risk of fraud through no fault of my own. Can you confirm that Barclaycard will compensate me for any losses resulting from such a fraud, including consequential losses?
Of course, this would be much easier if they'd just email me statements. But Barclaycard clearly aren't great fans of email, and have obviously invested so much in their rather feeble web efforts that the chances of them switching to a more sensible internet protocol now are pretty small.
I was struck by this letter in this week's Economist:
SIR-- I had occasion to speak confidentially with Edward Teller during Ronald Reagan's second term (Obituary, September 20th). As he was credited with authorship of the Strategic Defence Initiative (``Star Wars''), I asked him how it came about. He said that Reagan fashioned a bubble with his hands and said, ``I wish I could put a protective shield over the country -- to keep evil people from doing us harm.'' Teller told the president his vision was possible.
I asked Teller if it would work. ``Now? No,'' he said and I asked why. He gave a bored shrug: ``The technology doesn't exist.'' This was an astounding admission from the chief architect of Star Wars. Though it failed it is still credited with hastening the downfall of the Soviet Union. Teller displayed a profound lack of interest in the morality of launching a massive programme he knew would not work, and an overriding interest in the morality of defeating America's enemies.
As a quick reminder, SDI was announced in 1983, towards the end of Reagan's first term. Teller's great contribution to the programme -- apart from apparently convincing Ronald Reagan that it was feasible -- was the X-ray LASER, a nuclear-bomb powered device intended to be deployed in orbit which would be used to zap missiles as they climbed away from their launch pads.
Teller claimed that one such LASER could shoot down the USSR's entire land-based missile force, if it entered its field of view. The X-ray LASER consumed something like a billion dollars before it was finally aborted in 1992, and the only thing it managed to shoot down was the 1986 Reykjavik summit, after Teller's claim -- based on falsified test results -- that the device was `ready for engineering development'. (This review of Teller's memoirs is also instructive.) Unlike other SDI technology like `brilliant pebbles' (originally `smart rocks', satellites designed to maneouvre into missiles, destroying them), the X-ray LASER isn't even phyiscally realisable, let alone practical.
(Now, there's an argument that, by forcing it to increase defence spending to compete with US spending, SDI helped to bankrupt the USSR, hastening its demise. Well, maybe. In fact, according to this 1987 CIA report, Soviet SDI Response Options: the Resource Dilemma, SDI didn't provoke significant extra spending on ballistic missile systems by the USSR:
... to our knowledge, the Soviets have not yet initiated major new weapons procurement programs in repsponse.
The Soviets apparently have proceeded on the assumption that they could delay responding to SDI with major new weapons procurement programs or the acceleration of ongoing programs until at least the early 1990s, when such responses could be incorporated in their 13th Five-Year Plan (1991-95). They will be making key decisions supporting this plan during 1988-90.
-- by that time, there was no USSR any more. So much for SDI bankrupting it....)
But that was all a long time ago. Today the missile-defence debate is about `rogue states', by which is meant those which preemptively invade other sovereign states... I'm sorry, that came out all wrong. What I meant to write was, those which develop ballistic missiles and warheads to defend themselves against states which preemptively invade other states. Of course, what I really should have written is `North Korea'.
It's well known that missile defence doesn't work, and is very unlikely ever to work. (The North Korean government knows this too.) There's a good report on the subject from the Union of Concerned Scientists, which explains why relatively easy-to-build countermeasures can be used to fool a hit-to-kill system of the type the Americans are building. (The description at the end of the report on the British Chevaline system gives an idea of what is feasible. It features, for instance, numerous light decoys which are powered by rockets so that even when the decoys reenter the atmosphere, they still travel at a velocity like that of a real warhead. The system was built at enormous cost to keep Polaris effective against anti-ballistic missiles around Moscow; those ABMs had nuclear warheads and were substantially more capable than the type currently being built for NMD. Countermeasures sufficient to deceive the proposed system would be much easier to build. Of course, for a `rogue state' bent on blowing up a city somewhere, this may be too much effort. As an old sketch runs,
We had that bomb dispatched to Moscow as soon as we got Alert Condition Red. They thought we had no way to deliver the bomb, but they forgot we have an excellent postal service.
(Peter Sellers, I think, but I may be wrong)
-- the Royal Mail may be in decline, but I understand FedEx still does OK.)
Even a working missile defence system would have other serious problems, since missiles built by North Korea will probably lack the expensive environmental sensors that keep US warheads from detonating unless they arrive on target after the right sequence of accelerations and changes in atmospheric pressure.
Apparently, Teller knew this all along. He was, after all, a smart man. And the fact that ballistic missile defence is a waste of money is hardly new or secret. So what's the point of spending $25.6 -- $48.8 billion on it (on top of the sums wasted on SDI)? It's hardly as if the US has trouble outspending North Korea in defence. Is NMD -- like the space programme -- just a way to hide a subsidy to the aerospace industry, or is there something else going on? If so, what?
After complaining yesterday about how tedious stitching images into panoramas is using GIMP, I finally decided to take a look at VIPS, a free image processing tool which is described as `half way between Excel and Photoshop'. (If the idea of that combination fills you with nameless dread, I suggest you don't read any further. I understand that this sort of geeky stuff puts off a substantial fraction of my half-dozen readers or whatever it is now. Sorry. I should probably also apologise for the worsening quality of the article titles here....)
VIPS is pretty cool. It's an enormous UNIX program which is a slight pain to compile, but if you're the sort of person who's willing to endure this sort of pain for `fun', that won't be too much of a barrier. Basically it consists of an image-processing library which supports a bunch of high-level operations (add, subtract, rotate, translate, ...) on images and related objects (points, lines, regions, matrices...). For those playing buzzword bingo, it does so via a pure lazy functional language with classes (put that in your shell and smoke it...), though it also has a GUI (`NIP') which exposes the high-level operations as an alternative to writing code. Rather entertainingly, when the GUI starts up, it displays the message,
© 2003 The National Gallery
-- which is nice for those who like to think of their random image editing as `art'. (The software is used for processing data such as infra-red reflectograms acquired while restoring paintings, which is presumably why the National Gallery has an interest in it; there's an example of the kind of thing in the documentation.)
One set of VIPS functions is used to create mosaics of images. The idea here is that you nominate similar points in pairs of images, and tell it to search for the best match via either a translation or an arbitrary linear transform. The user-interface is rather nice:
Each image or other object you create occupies a cell, like a number would in a spreadsheet. In the simple example above, there's just one column, but you can have lots of columns if you want (I haven't used this yet and aren't quite sure why I'd want to. Whatever). Any operation you do creates a new cell. So in the above example, I load two images which become A1 and A2. I then identify two corresponding points in those images, which are A3 and A4. I then do
(there's a menu option for that...) and VIPS figures out how best to glue the images together into a composite. (Unlike, for instance, pnmstitch, this step actually works....) The last step is an operation to balance the contrast between the images in the mosaic, so that the colours are consistent throughout. This step isn't perfect, but it's a damn sight better than manual adjustment using the `curves' tool in GIMP. I haven't yet got it to do all the colour adjustment I want -- in particular spatially-varying adjustment to fix variations in colour around the edges of the image caused by suckiness in my camera -- but VIPS is clearly powerful enough to manage it -- given enough time to learn how. (Attempts so far have made it crash. Natch.) Helpfully the manual for its internal API consists of a list of functions with the useful caption,
Table 6.4: Useful utility functions -- see the source for details
(Truly this is the future of software.)
Anyway, here's another panorama I knocked together fairly quickly with this thing:
-- about ten times more quickly than I could in GIMP.
Spot the difference:
``Over the last twelve months we have made a step change in how we set about tackling anti-social behaviour with a dedicated Home Office unit [new bureaucracy] to lead the way bringing in tough new powers, helping local agencies [more new bureaucracy] to work together with the community.
``We have increased the numbers of police officers, community support officers and neighbourhood wardens across the country and given them more tools -- improved ASBOs [anti-social behaviour orders, i.e. more paperwork], acceptable behaviour contracts [more paperwork] and fixed penalty notices [yet more paperwork].
``Local authorities and communities need to use these tools [i.e., bureaucracy and paperwork], to ensure that the tiny minority are not allowed to continue to blight the lives of the law abiding majority.'' (David Blunkett, speaking at the `the Home Office Anti-Social Behaviour Conference' -- i.e., a talking-shop)
(Obviously it would be inappropriate to judge the likely effectiveness of this new Home Office gimmick^W policy on this basis. It may well be that bureaucracy and paperwork are the best ways to tackle anti-social behaviour. On a slight tangent, a recent report suggested that police officers on patrol aren't much help, but in fact that research was so statistically naive that it wouldn't be safe to conclude anything from it.)
On a different tangent, I was interested to see reports in the Sunday newspapers about Blunkett's ID card scheme going aground in the face of opposition from his Cabinet colleagues on the surprisingly-practical grounds that the cards will be expensive and useless. Of course, you can't believe anything you read in the Sunday papers. Anyway, this morning Blunkett resorted to the time-honoured trick of invoking the vox populi:
``... over the summer and in this autumn, even when I've been travelling, people have come up to me again and again and said `stick to your guns, we know that if we're going to sort out clandestine entry, clandestine working and illegal use of our services, we need some form of identity card: a modern, biometric card that can't be forged.''
... as ever, the idea of a card that `can't be forged' would be hilarious except for the fact that Blunkett apparently believes that it's a practical possibility. As for biometrics, I'll let my previous comments stand.
Of course, objections on practical grounds won't necessarily have much effect, and bringing in ID cards wouldn't exactly be the first time this government has funded something expensive and useless. And if Blunkett is taking his job seriously -- by which I mean trying not to foul anything up too badly at the Home Office while pushing through some big headline-grabbing project or other in order to maximise his chances of being the next Prime Minister -- then ID cards are an invaluable asset. Unlike Jim Hacker, he can't go to work on a sausage; but maybe an ID card will suffice. If his reading of the vox populi is true and people in this country really do want to spend £40 to £400 each on a useless piece of plastic tat then I suppose picking a fight with Gordon Brown over the cost of the thing is probably a good idea.
Update: I should have linked to this Sunday Times story, which also has the text of leaked letters from Jack Straw and Paul Boateng. It's interesting that the list of Straw and Boateng's concerns -- that the card can't be demanded compulsorily in order to get access to services, since not everyone entitled to use the services will have a card; that the payment for the card may be classified as a tax; that the introduction of the card will decrease revenue for the Passport Service and introducing biometrics will increase costs; and that there are legal problems with how the card would interact with travel within the EU -- are quite different from the objections of informed members of the public -- namely, that the card will be expensive, won't solve any of the problems claimed, would infringe civil liberties, and is un-British. The letters assume that the card might be some use; that biometrics are a useful security feature not a gimmick; and, in general, that the card is actually a reasonable idea with some practical problems in its way.
So today I'm going to tell you about the walk I went on yesterday. (This isn't necessarily of any interest to anyone, but this is my web log and I'll do what I like with it.)
We went to Kings Lynn, which is the town at the mouth of the Great Ouse at the southern end of The Wash, with the intention of walking to Hunstanton. This was optimistic. We didn't make it quite that far. You can see an approximate map of our route. Image produced from the Ordnance Survey Get-a-map service. Image reproduced with kind permission of Ordnance Survey and Ordnance Survey of Northern Ireland.
Kings Lynn, years ago an important port, seemed an ugly town replete with chemical works, oil depots, one-way systems, intermittent train services and sundry other modern inconveniences, though the center of the town is apparently very attractive, with many fine buildings. We cleverly avoided seeing any of these by immediately heading north out of town and making an erroneous detour through an industrial estate. At almost any distance from the town, it's that which dominates the skyline:
North Norfolk isn't known for its hills, and anything which sticks any distance above the ground is visible for miles. These electricity pylons, carrying cables high enough over the mouth of the Great Ouse that ships can pass safely underneath, can be seen for miles around:
For most of the walk, we followed the sea bank (flood defence) along the shore of the Wash. On one side is salt marsh, and on the other arable land reclaimed from the sea over the past four centuries.
Strictly speaking this is private land, though many web pages about walking this part of the coast mention walking this way without trouble. We were accosted once by a chap in a Land Rover, who pointed out that we were not on a right of way. He was, I think, under the impression that we were lost -- although we were walking purposefully in a straight line, equipped with a map, and by this stage we were five miles from any road -- and he conceded -- after a short and uninformative conversation -- that our quickest way back to civilisation was to continue in the same direction. He also warned us against straying onto the Sandringham Estate, despite the fact that doing so would have required going off course by about 90° for a distance of several miles. I guess we must have looked pretty clueless, which was exactly the impression we were trying to create. (And we didn't get shot, either, for which small mercy much thanks.) Naturally if we'd been challenged again we would have explained that we were acting under previous instructions, but this didn't occur.
The sea banks are about ten foot above their surroundings, and are not the easiest of walking surfaces. It's usual to describe the surrounding landscape as `bleak'. Here's a picture, looking along the bank:
Even in an essentially flat landscape, walking along a path raised above the surroundings, it's necessary to consult a map...
... if you don't want to get lost.
Looking inland, you see something like this:
Apologies for crummy panorama. Mark refers to this technique, rather scathingly, as `the poor man's wide-angle lens', which is about right. He's also much better at sticking the images together than I am. For those Windows users out there who'd like an opportunity to laugh at the current advanced state of free software user-interface design, you can have a look at these rather disheartening instructions on assembling composite images using the GIMP Photoshop-alike, paying particular attention to the bit where you're supposed to tabulate colour values and manually construct transfer functions to match images up with one another. Plainly, even UNIX users aren't living in the future yet.... And a word of advice to others taking panoramas -- don't try putting a ploughed field in the foreground. It will only cause you misery.... There are some much more impressive examples on the website about David Cotton's six-thousand-odd mile walk around the entire coastline of Great Britain. (Comments about fractal dimension probably not appreciated.)
Eventually, we got bored of walking and stopped for lunch. Oddly enough, this was at exactly the same time that we reached a public footpath where we thought the chances of a shotgun-toting farmer objecting to our cooking stuff were small enough to take the risk. None of us actually live in Islington, but you might be forgiven for thinking otherwise:
(Not quite as bad as the time when, at my birthday party, somebody put out a small barbecue-related fire with mineral water. ``Dial 999-1 for Islington Emergency Services.'')
Further north the coast path follows the shoreline, offering charming views of the mud which caused King John so much trouble:
This is also the location of the Snettisham nature reserve, home to ducks and geese in large numbers. (Further south they shoot them.)
(By this point it was quite dark, hence rather long exposure in that photo....)
The mud is also, apparently, where you park your yacht (if you have one):
At the end of the walk, we watched the sunset at Shepherd's Port (a depressing encampment of caravans and `Residents Only' signs that's just begging for a tornado or other appropriate natural disaster) and got a taxi back to Kings Lynn. This is, of course, cheating. But what's wrong with that?
Nick Barlow draws to our attention a comment by George W. Bush:
Free nations don't develop Weapons of Mass Destruction.
-- and by way of comment, links to the sites for the UK's nuclear weapons operation (now privatised...) at Aldermaston and this map of weapons sites in the United States. Or we might look at France's efforts in the field; or perhaps (for those foaming-at-the mouth, freedom-fry munching ingrates on the web's lunatic fringe) those of Israel or of India, the world's largest democracy. Alternatively, we could consider biological and chemical weapons.
So, Bush ignorant -- or hypocritical. What's new?
Not much. But there's a more interesting point here, to which I have alluded before.
The term `Weapons of Mass Destruction' is Newspeak, a way to mask a great big lie. Lumping nuclear, biological and chemical weapons together in one category is a way to justify using nuclear weapons to deter other states from developing chemical and biological weapons -- and using nuclear weapons might be an effective way to destroy those chemical and biological weapons before they were used. Doubtless this is sound military logic, though in these uncertain times I'd advise reading this before you consider living anywhere near a factory making ibuprofen or baby milk.
In fact, there's no comparison between the destructiveness of the hydrogen bomb and of chemical and biological weapons. The idea of sticking all three types of weapons into one category is as a way of justifying US threats to retaliate against states which use chemical or biological weapons with nuclear weapons. The implication: that use of sarin or anthrax is so serious that retaliation with a hydrogen bomb is justified. (See, for instance, this piece by Daniel Ellsberg which traces this trope back to the last gulf war, or any number of pieces in the Bulletin of the Atomic Scientists on proliferation -- start with this one and search the archives.)
Sadly, the category of `Weapons of Mass Destruction' is very appealing to the ignorant -- especially in the press -- and those who seek to mislead, and so, over the past couple of years, we've seen hijacked aeroplanes, missiles armed with conventional warheads, suicide bombers, and even ex-Cabinet Ministers like Clare Short and Robin Cook described as falling in to the category. More than fifty years ago, Orwell warned against using terms which have become meaningless through overuse:
Many political words are similarly abused. The word Fascism has now no meaning except in so far as it signifies `something not desirable.' The words democracy, socialism, freedom, patriotic, realistic, justice have each of them several different meanings which cannot be reconciled with one another. In the case of a word like democracy, not only is there no agreed definition, but the attempt to make one is resisted from all sides. It is almost universally felt that when we call a country democratic we are praising it: consequently the defenders of every kind of regime claim that it is a democracy, and fear that they might have to stop using that word if it were tied down to any one meaning. Words of this kind are often used in a consciously dishonest way.
-- the same advice applies to `Weapons of Mass Destruction'. Those who don't know whether they're talking about nuclear, chemical or biological weapons oughtn't to be pontificating on the subject anyway.
This is all done with wwwitter.
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