Wednesday, 8 October 2008

Talking ourselves into a recession

This morning I had an interesting conversation with a work colleague regarding the dubious present state of the financial system over our usual mug of ultra-strong coffee. I have always tried to shy away from writing social criticisms and keep my blog purely science based, but for this I'm going to make an exception. As a vaguely scientific side note, however, our coffee would normally make a good high school science experiment since it behaves more like a glass than a liquid. I'm not sure whether this is purely a factor of the percolation time, or a combined effect with the obscene amounts of sugar vigorously stirred into it, but, either way, this coffee could quite easily go undercover as treacle.

Today's caffeine fueled discussion stemmed from an
article published on BBC News yesterday. Entitled 'UK economy already 'in recession'', it is one of the millions of stories being run on news websites and in papers around the world regarding the impact of the present economic crisis on society at large, i.e. levels of unemployment, high-street spending, manufacturing, etc. The point we were talking about was not the comments on rising unemployment, etc (all of which are very valid and supported by statistics from the British Chambers of Commerce), rather that half-way down it proceeded to say 'Technically the UK is not yet in recession...'.

Hang on one cotton-picking minute! First you say we're in a recession, then you say that, according to the guidelines by which economists define recession, we're not - guidelines which have some well founded mathematical basis.

Don't get me wrong, I know full well why headlines such as this are printed. I am all too aware of the way journalists will twist stories to be more dramatic if they think it will result in more sales. The kernel of our discussion this morning revolved around the fact that, normally, the application of such writer's license effects only a limited number of people. Take, football, (soccer to any Americans reading this) for example. The amount of bad press placed on the England football team after a poor performance has many times affected the confidence of the players and therefore their subsequent performances, resulting in the demise of a number of managers in the process. But, this effect is limited to the team and their immediate circle. Although poor performances leading to us not making a major competition has been shown to cause a drop in revenue for sports bars, etc, in general terms this impact is low.

With the economy, the story is a different one. The western economy is closely coupled to the performance of the stock market, when the market is in a period of growth the economy will grow too, and vice versa. The danger of the stock market is that, to a large extent, is is driven by the mood of it's investors. If they get twitchy and start panicking then all hell breaks loose (as was seen with the Northern Rock debacle earlier this year). Unlike football, in this case any fall out from bad press can effect everybody as overly dramatic stories bemoaning the 'almost' recession cause investors to become less pragmatic and the market to plummet and the economy to wobble. As the news article itself pointed out, this then feeds back into the general public with job losses, etc, which then feeds back into the economy with less high-street spending to prop up the markets, i.e. an economic circle of death.

So, in conclusion, I ask the question we talked about over coffee. By printing and talking all this doom and gloom regarding the state of the economy, are we in fact talking ourselves into a recession when otherwise the markets would have dipped but stabilized?

Tuesday, 7 October 2008

Don't forget the old ways

Recently I've been spending a large part of my time writing quite a complex bit of new code to process the seismic data we acquire using our 3D chirp system (those of you who've been paying attention will remember me talking about this a little while ago). Going through this process I've become increasingly aware just how much we take for granted the insane amounts of computing power those of us in active science research have available to us.

Although the process I'm trying to accomplish (3D seismic imaging) is not in either conceptually complex, nor difficult to write as an algorithm, it is difficult to do well. This spawns from two main factors: firstly, our obsession with data redundancy leading to enormous amounts of data being pumped in at the beginning; and secondly, the complex coupling between acoustic waves and their host medium making modelling the propagation of sound in geologically complex areas mathematically expensive (equally, this can also be thought of as a problem resulting from our desire as scientists to push the limit and explore more challenging environments).

The former problem is the one I've been mainly struggling with. The nature of our system means that trying to produce an imaged volume requires the manipulation of an incredible amount of data. For an average survey you're talking about having 10 - 15 million spatial samples, each consisting of 3000 - 4000 measurements of the reflection energy recorded at different times. To image this, the data has to be converted into the Fourier (frequency) domain since the propagation of acoustic wavefronts through a medium is frequency dependent. This produces a further 1500 - 2000 data points for each time measurement, giving a total of about 1.2 x 10^14 (120 trillion) data samples to manipulate! Not to mention a windowed Fourier transform before and after!

When handling data on these sorts of volumes it's easy to forget that altering the location of a single calculation within the code can dramatically affect it's run time. Simple things, like moving a variable calculation out of a for loop so that it is calculated only once for each frequency component on each time series shaves, literally, days off the processing time. Equally, a clever bit of sorting of your input data can enable the application of a single calculation to time series from multiple surface locations.

These techniques are not new, as sundialsvcs pointed out in this thread on I recently stumbled across. There is a tendancy with the processor power and memory volumes available at increasingly reasonable prices for our coding to become more slapdash and less optimized. The application of a little thought and some of the tricks commonly employed when computers were beasts that filled entire rooms could, I think, cut swathes off our (by this I mean scientists) processing time.

Also, talk about cutting energy usage to save the environment - imagine how much greener it would make us!

Monday, 6 October 2008

A fifth force farce

Over the weekend a good friend of mine from undergrad sent me a link to this site discussing a joke publication on the discovery of a fifth fundamental force.

Personally, all credit to the guy! Threatening to take the mickey and submit a spoof paper, be it as an April fool or whatever, is something I think most people would talk about (probably somewhere between pint number 4 and pint number 5), but then casually side step when it came to actually joining pen and paper. But not Lawrence Krauss, oh no! He threatened, and then had the balls to back it up.

There are a couple brilliant bits in his article, but I think my personal favorite has to be reference 6:

'6. Thanks to the intermediation of high-ranking officials from certain Italian banks, Vatican archival material was made available to us.'

As good a spoof as the original manuscript is, he was completely out performed by the 'reviewing' team from PRL. Their report is a work of genius. This line from the editor had me in stitches for a good while:

'In addition, we feel that the general interest (and even novelty if you want to be arcane about it) no longer supports the discovery of new forces. Already five have been reported in the literature and we think the time has come to draw a halt to the unbridled publication of force discoveries.'

Hopefully most readers of the science blogosphere, especially those who've ever had the privilege of trying to sift through reviewers comments, should appreciate this as much as I did. Enjoy!

Thursday, 2 October 2008

Cosmic Variance Challenge 2008

In the US there is a tradition each year for DonorsChoose to use the impact of the internet to provide extra funding to classrooms all over the US with their Bloggers Challenge. This year, one of my personal favourite blogs, Cosmic Variance, has got involved with their very own Cosmic Variance Challenge 2008.

I'm sure any donation to this worthy cause would be much appreciated (even more so if you can help them beat ScienceBlogs!)