A quick note to say that I’ll be leaving on a 12-day tour of Botswana and the Victoria Falls tomorrow morning. We’ll be in quite remote areas for much of it, so I may not respond to email quickly. But you’ll be able to read all about it here once I get back!
30 Jul 2005
28 Jul 2005
In the spirit of wardialing and wardriving (see also this), I’d like to propose a term for what the modern low-budget but tech-equipped long-distance flyer (like, say, me) seems to spend much of their time doing: wartravelling.
I have nine hours to kill in JFK airport, New York, between my short and long overnight flights. I had been thinking of hitting New York, but due to certain uncertainties in travel plans, I’ve decided to do some work in the airport and check in as early as possible.
So that leaves me searching for somewhere to sit, featuring (a) a wall power socket, and (b) free wireless internet. Frequently the former can be found at a restaurant, which has the added advantage of waitstaff bringing food and drinks. The free wireless, however, can be tricky, and sometimes requires a little … exploration. Or, as we shall now call it, wartravelling.
In my case it’s worked out quite easily. A huge shoutout to the Swiss and Varig frequent flyer lounges, for sponsoring my wireless internet (though probably without actually realising it). Terminal 4, JFK, the shops before the security checkpoint. I suggest Delancey’s Bar for the most comfortable seats.
Now if only I could stay awake…
27 Jul 2005
I’m now doing the last of the packing and organising before leaving this evening for New York, and then Johannesburg. It’s the usual marathon two days of travelling — but at least I should sleep well on the plane, having not had much sleep this week.
While in Southern Africa I’ll be spending about 10 days in the Okavango Delta, in Botswana. I’ve never been there before, and am really looking forward to it. It’s a huge inland wetland, full of all your favourite African animals, and some beautiful scenery. Many of the camp sites are on islands, accessible only by canoe. Then I’ll be seeing family and friends in Johannesburg, most of whom I haven’t seen in a whole year! And, of course, the benefit / curse of theoretical physics is that it’s portable, so I’ll be taking along some of that too.
Though all of the above is somewhat dependent on whether my flight actually flies. South African Airways (SAA) is in the midst of their worse strike ever — all the cabin crew are on strike, so most domestic and virtually all international flights have been cancelled for the last five days. I can only imagine the havoc caused by hundreds of flights being cancelled — especially when flights to South Africa are almost always fully booked, so it’s really tricky to route through another airline.
Apparently agreed beforehand was that cabin crew overseas at the start of the strike would carry on working till they returned home, so apparently SAA was flying some empty (!) 747’s to Europe and North America, to continue what flights they could.
It seems that SAA management really messed up the wage negotiations. They were claiming that they couldn’t offer more to the cabin crew due to SAA’s tight financial position, but midway through talks they reported excellent operating profit for the year. The result was something of a plausibility problem.
UPDATE: Just reported on Google News is that Unions have accepted the latest revised offer, so it looks like the strike might be ending. The problem is that it needs to end soon enough for a plane (with crew) to fly for 18 hours to JFK, to be waiting for me to board it tomorrow. Nothing like life on the edge!
18 Jul 2005
A brief timeline of my afternoon:
2:40pm: Posted advert on craigslist, for a sublet of my room for the month of August, which I’ll be spending in sunny (though cold) South Africa.
3:01pm: First reply. Guy sounds a little … intense.
3:27pm: Second reply. Guy says that this is one of his options, not willing to commit yet. I dislike the fear of commitment in others.
3:46pm: Third reply. Recent graduate from Boston University, needing somewhere to stay while looking for an apartment from September.
3:55pm: Phone above person. Agree on terms, make sure he sounds reasonable, discuss how his previous roommate washed his clothes in a bucket with a plunger. Agree to sort out payment in the next few days.
So in less than 90 minutes, I’ve just made $500 for myself, thanks to craigslist. By renting a room that was furnished substantially off craigslist.
15 Jul 2005
Soduku (Sudoku) is a Japanese number puzzle game that seems to be taking the world by storm. It’s played on a 9×9 grid. Each square can contain one of the numbers from 1 to 9 (inclusive). A given “problem” has some of the squares filled in, and you are required to fill in the remaining squares, satisfying the constraints:
- Each row has to contain each of the numbers 1 through 9 exactly once.
- Likewise for each column.
- The board can be broken down into 9 3×3 squares (top-left, top-middle, top-right, etc.). Each of these has to contain each of the numbers 1 through 9 exactly once.
Anyway, these puzzles can get pretty tricky. Especially if you don’t know the third rule above — which until recently, I didn’t. Anyway, they’ve sufficient annoyed me now that I had to do something about it; so I wrote
It’s not fancy, but is (in my opinion) very efficient. Enjoy!
Edit: Now available: an explanation of the method my solver uses, and the source code.
13 Jul 2005
I confirmed on Monday that Caltech’s gym does indeed have a climbing wall, and yesterday I decided to try it out — and get some value-for-money on my climbing shoe purchase too!
To be more accurate, it’s not really a climbing wall, as it’s not high enough to need a rope. Rather, it’s a bouldering wall, with a whole lot of holds on wooden panelling, inclined at various angles from vertical to completely overhung — ie. the ceiling. The floor is covered with thick padded matting, as used in gymnastics. It’s installed in this weird hole in the wall in the side of the old gym, with more of a cave feel than a cliff face. Most of it is beyond my current skills, but I managed to get some good traverses in. It’s excellent finger strength work, and a good physical challenge after the mental challenge of trying to find things to do to procrastinate, all day (and with only mixed success).
I’m generally more of a fan of outdoors climbing, rope and all, but the advantage of this is that it doesn’t require a partner and lots of equipment, not to mention hours of travelling. Nevertheless, I’ve been looking around for some climbing partners for an occasional trip, and have one or two good leads already.
Anyway, if anyone is interested in trying it out, the gym even has climbing shoes for loan, for free!
10 Jul 2005
One of the key challenges that arises in almost any context is how to deal with complexity. Probably the most powerful tool we have to address it is abstraction — ignoring details in favour of a smaller set of information, at some “higher level”. I’ve been thinking recently about how abstraction appears, with varying success, in so many areas, and in particular what differentiates different problem areas in which abstraction is more or less effectives. This two-part post will meander vaguely through a few of those areas.
I’ll start, appropriately, in physics. Thermodynamics is an excellent example of abstraction at it’s best — macroscopic quantities of gas, say, have on the order of 10^27 molecules, but we can describe their behaviour very well using only the variables temperature, pressure and volume. Thermodynamics passes two test I’d like to propose for the appropriateness of abstraction:
- There exists a useful cutoff scale. Considering the behaviour of the gas at “macroscopic” length scales is a well-defined, useful definition, since the molecules are so much smaller.
- The different length scales decouple well; or to paraphrase, there is little behaviour loss from ignoring interactions at a smaller scale — thermodynamics describes the gas really well.
Physics is full of such examples — in fact, many physicists consider it a very non-trivial fact that physics can be split into so many different length scales, and described accurately at any of those length scales. Newtonian mechanics works universally at the human-scale level; quantum mechanics and field theory is superbly accurate at atomic lengths, even though we know it’s an incomplete theory. Indeed, quantum mechanics predicts infinite energy interactions at shorter lengths, but nevertheless our results are superbly accurate, even though we don’t even have a theory that deals convincingly with those infinities. It is, in fact, a useful approach to actually model the dimension of “scale” as a physical dimension, so that physics at different energies actually happens at different places in this fifth dimension.
But to consider complexity more generally, physics is also very ameniable to abstraction in complexity of the number of objects involved. Physics can be done very nicely by considering the interaction of only two or three particles at a time. This is, in my opinion, largely the reason that “serious” physics is much older as a discipline than most other sciences: most physics can plausibly be done by individuals, without computers. As a result, it’s been “tractable” for far longer than other disciplines I’ll discuss later.
There are a few cases where one or both of the requirements above don’t hold, and it’s those areas of phyics that are particularly hard. The surface of a black hole is a region of such strong curvature and energies that the normal approximations of long-range behaviour that general relativity makes don’t hold, and we need (somehow) to take into account quantum effects. Thus there is no useful cutoff that we can define, and the complexity problem makes general relativity inapplicable. On the other hand, in the photoelectric effect (electric current generated by electrons being excited by incoming light) we have a useful cutoff — we can measure current and light intensity. However, in taking a macroscopic cutoff, we lose important information: because photon energies and electron orbits are quantised, increasing the intensity of the light increases the number, not the energy, of the electrons produced. This observation was vital to the birth of quantum mechanics.
Abstraction is one of the cornerstones of modern computer science and application design. Object-oriented programming (OOP) is now used universally in large programs. OOP directly addresses criterion 1 above (of cutoff scale) by requiring the programmer to split the program into “objects” that then communicate in a simple, well-defined manner with each other. Thus one defines a cutoff scale at the level of objects, making a program with no intrinsic cutoff scale ameniable to abstraction. Furthermore, it is a key requirement of well-designed objects that they have no hidden side effects — after taking the cutoff, a lot of design work is put into making sure that criterion 2 above is satisfied too. So in fact much of the improvement in techniques of software engineering in recent decades have resulted just from making programming ameniable to abstraction.
Economics is a great example of a discipline where clear cutoffs exist, but where predictions are less than ideal as a result behaviour loss, or leaking of effects from behind the abstraction. For example, economists typically use the model of a perfectly rational person (homo economicus) to construct models of economic behaviour. So, for example, one defines a price vs. demand curve, showing demand for a good (item) at any particular price level. One assumes this is a decreasing function — as price rises, demand falls. This is often the case, but a lot of recent work has been looking at cases where it isn’t. For example, it turns out that people are, in some situations, more risk-averse than the odds should suggest. Furthermore, sometimes higher price can be used by consumers as a signal of quality, and can actually increase demand. The effects of consumers having imperfect information, or showing brand loyalty, or even following fashion, are all significant but are very hard to include in the simple abstractions that have traditionally been used.
In the second part of this marathon post, I’ll look at why biology, and even more so psychology, have much greater complexity problems than physics (yes, it’s because abstraction doesn’t work well). Also, I’ll look at how the human brain uses abstraction absolutely everywhere — and some of the funny effects and failures that arise from behaviours leaking through from behind the abstraction (criterion 2 above). I’d be interested in thoughts that anyone has on other areas that show interesting applications of abstraction!
7 Jul 2005
Tony Blair is, on current form, likely to be remembered for two, perhaps three, major foreign policy drives. The first is his staunch support for the war in Iraq; the second is his efforts to promote debt relief and trade with Africa; and the third may come to be his influence on the direction of the EU, and in particular it’s funding emphasis.
I write this in the immediate aftermath of the attack on London. It’s a little risky writing before the details have become clearer, but it would seem that al-Qaeda has succeeded in attacking the US’s great ally in the Iraq campaign. My condolences go to all the victims of the attack, their relatives, and all affected. Once again the victims of violence are people who had nothing to do with the “causes” of the war in the first place, or even necessarily supported Blair’s conviction that invading Iraq was the correct thing to do.
What really stands out for me, though, at this time, is how Blair’s earlier warlikeness is making his peacetime efforts so much harder. The attacks seem to be synchronised with the G8 industrialised nations summit in Scotland, 4-8 July. Blair has, to his great credit, managed to make Africa (and climate change, another vital issue I won’t get to here) the focus of this summit. Substantial progress has been made in recent months towards measured relief for heavily-indebted developing countries, and the G8 meeting represented the best chance for a long time of real change to help Africa: entrenching debt relief; opening of the developed world’s insanely restricted agricultural import sectors; support for leveling of the global trade playing field leading into the World Trade Organisation meeting later this year; and the doubling of aid to Africa by 2010. And, for a change, it seemed that other leaders might be willing to make commitments.
Recent weeks have also seen a huge movement across the world to exert public pressure on the G8 leaders to make things happen. Notably, many have travelled to Scotland (including our own Holly), and a who’s who of rock bands have been playing Live 8 concerts around the world to raise awareness. By all accounts, they’ve been very succesful, and I have been very excited to finally see things happening.
Right until the London attacks. The focus of the media and global interest will be pulled inevitably away from building a better, fairer world, to the strife of the last few years. Once again people will be talking vengence or security, rather than cooperation or social justice.
The G8 leaders have said the conference will continue, but these attacks will have had a heavy toll not only for the people involved, but for the millions who will have to endure preventable poverty for that much longer. I can only imagine the bitter disappointment in the hearts of those, like Blair, who had been driving recently for positive change in the world. The moral for today: war doesn’t solve problems, and has the nasty habit of causing knock-on problems in all sorts of apparently-unrelated areas.
Growing up in Africa, as I did, means I missed seeing a lot of the “classic” movies that define our generation. I mean, I had to spend my leisure time caring for my elephant, so I could get to school the next day. And movies arrived by camel, about a decade late. But we didn’t have electricity to watch them, anyway.
Or perhaps it’s just that I never lived in a dorm at university. Well, regardless, I seem to have missed out on seeing quite a few classics — whether good or terribly, hilariously bad. The topic came up at TASI last month, and now (with much thanks to Michelle and others), I have the beginnings of:
- Fish Called Wanda
- The Beastmaster
- Man Who Fell To Earth
- Harold & Kumar go to White Castle
- Dirty Rotten Scoundrels
- Without a Clue
- Finding Nemo
I’m going to be working my way through the list in the coming weeks (months, years), with company if anyone is interested!
Exercise for the reader: What’s been left out? Add it in a comment below!
UPDATE: I’m going to cross out movies I’ve seen. Some might argue that it’s a little unfair crossing out things on the basis of my viewing alone — but then hey, this is my blog, afterall.
4 Jul 2005
Well, I’m back in Pasadena, after an especially busy two weeks. So busy were they, that I haven’t posted to the blog in quite some time. Ooops!
Anyway, the last weeks of TASI were most excellent. We had some very interesting lectures, and I may also be starting some interesting collaborations with other grad students at other universities. We also went out with a certain very famous string theorist on the last Thursday evening, and had a pretty wild time. It’s quite an experience hanging out with someone who’s so famous — even if the fame extends only to a very small group of people. Anyway, more photos should be following shortly, once I get them organised.
Arriving in my apartment was, however, was full of surprises (well, I knew about them, but they were still unusual), in about the following order:
The cat: We’re hosting Katie’s cat Bailey, while Katie and Ted are on honeymoon. As an aside, the wedding was last week in Illinois, and was a great time. More to follow on that, too, hopefully. Anyway, it’s strange having a cat around the place — especially when it wants to share one’s lap with a laptop.
The furniture rearranged: Ariele seems to be the instigator of a rearrangement of the lounge in our apartment. Now a change is as good as a holiday, but in this particular case, it seems that her reasons were essentially so that I would feel confused when arriving home. Or something like that. Well, I win this round — I quite like the new look, and feel NOT AT ALL out of place. 1-0!
My room! AAAAHHH, my room!!!! Jeff’s been staying in my room for a few weeks, while I’ve been away, and until Ariele and him get their new apartment. It’s worked out very nicely, but has meant that I arrived to a room FULL of his stuff:
We’re now in the process of helping them move to their new place — which has a pool! Hanging out by a pool counts as work, right?