Friday, July 15, 2005

Bastille Day, or Why Soldiers are like Oil Reservoirs

I have now been in France for just over two years. I arrived here in June 2003 and so was able to view the Bastille Day events of that year. There are two sides to Bastille Day. One of them is the celebration of the storming of the Bastille and the founding of the French Republic. The other is the celebration of the military strength of France in the form of a parade down the Champs Elysee with an inspection of the troops by the president in the Place de la Concorde,

In 2003, the first time I watched the parade, I found it rather upsetting because it brought home to me the terrifying reality of the attacks going on in Iraq at around that time. Suddenly, the aerial bombing of Iraq was not just a little TV screen showing flashes on a night time scene over the rooftops of Baghdad, accompanied by distant thuds. Instead, I felt for myself the physical tremors made by squadrons of low flying jets going through my body and the terrifying roar of six or seven jet engines bursting over a narrow street.

In 2004, I wanted to take my family to see the same event, but I had forgotten how early in the morning it starts. You really have to be on the Champs Elysee by 9 a.m. which means, in the case of my family, getting up at 7 a.m. A not very likely start to a public holiday! When we did eventually get in to central Paris around 10.30, we weren't allowed to get out of the Metro as all the stops near the Champs Elysee had been shut as a security measure. When we did eventually find our way there, all we saw were some horse guards being pursued by a street cleaning lorry picking up horse droppings and a roller-skating policeman taking advantage of empty boulevards to do fancy foot manouevers at high speed.

Before I went to the event this year, I asked a few of my colleagues if they were going, thinking they would be, but got a rather surprising response: "Oh, that. No, I'm not going. In fact, I've never watched it." I started to get the impression that there wasn't much interest among the French. I suppose familiarity breeds contempt. My thoughts were somewhat confirmed when we arrived (on time) to watch the parade today and found ourselves surrounded by: Canadian, Japanese and American tourists. The French themselves seemed to be in a minority, and one of them wanted me to take pictures of his son as he marched past. So, perhaps only 30 or 40 % of the crowd were there for purely patriotic reasons.

This year, as we stood there in the hot sunshine, watching the soldiers in front of us surreptitiously passing bottles of water around to try and avoid succumbing to the combined effects of heavy boots and heavy rifles, I noticed how neatly the cohorts of soldiers were arranged. Not only did the soldiers stand in rows with the tallest in the front row and the shortest in the back, but also, within each row, they were arranged so that the tallest soldiers were on the right hand side and the shorter were on the left. This meant that each squad of soldiers had been perfectly sorted according to height. They marched in squads which were twelve men wide by ten men deep (they were not all men I hasten to add).

In the military, discipline is considered the most important component. The physical manifestation of discipline is order. Thus these squads, perfectly arranged and marching in time, represented a perfectly disciplined army. Such order can also be easily represented in the abstract in a 3D computer modelling program. Imagine the soldiers are a sort of fishing net and each soldier is a knot in that net. In computer jargon, the knots are called nodes (noeud in French = knot in English). Each node now has three sets of data. The first set of data is the soldier's "i, j" position in the net where i = row number and j = column number. The second set of data is the soldier's geographic "x, y, z" coordinate where x = latitude of soldier on the Champs Elysee, y = longitude of soldier on the Chanps Elysee and z = elevation of the Champs Elysee above mean sea level. The third set of data is the height of the soldier. Viewing this data with the computer 3D modelling program, we would not worry about viewing the height data as arab numerals since all these numbers would be difficult to comprehend. Instead we would apply a rainbow colour scale with tall soldiers in red and short soldiers at the other end of the rainbow scale in indigo. If we now viewed the 'net' (or 'grid' as it is usually referred to in the computer speak) we would see a rainbow stretching from one corner of the rectangular grid to the other: a nice neat arrangement of data.

Now that all the information is digital, it is also possible to view the data as a distribution function. Assuming an element of randomness in the original selection of the soldiers from their unit, we would no doubt discover a Gaussian or normal distribution of the soldiers' heights since that is the distribution that normally applies to naturally occurring populations where most of the variation is confined to the two tails of the population (very tall or very short soldiers in the first and last row and the rest more or less the same height in the rows in between). We could also add other data to each node of the grid: age of the soldier, weight of the soldier, fitness level of the soldier, firing accuracy of the soldier. With all this data, we could start to build up a detailed model of the properties of this squad of soldiers and their likely effectiveness in battle, not just as a qualititative feeling, but as a quantitative model.

The grid made up by the marching soldiers (who could just as easily be imagined marching into battle) is little different from the grid of rock properties that reservoir geologists create when they are trying to describe the 3D distribution of reservoir rock properties inside the earth. The geographic coordinates are exactly comparable, but instead of height, a geologist might map rock porosity (how much fluid, either oil, water or gas, can be held in the rock), or rock permeability (how easily the fluid can flow through the rock). When the geologist has finished creating the model, which is termed the static model, it is handed to a reservoir engineer who takes the grid of properties and simulates the flow of fluids through the rock in order to see how much oil, gas and water will be produced from the reservoir. This model is called the dynamic model.

The advance of an injected water front used to sweep oil through a reservoir towards producing wells is little different to the sweep of an advancing military force through a defended position. The algorithms used by military planners to model battlefield simulations that predict the likely outcome of a conflict are not very different to those used by reservoir engineers trying to predict the ultimate recovery factor of a reservoir. The battlefield simulator is likely to have as much interest in an individual soldier as a reservoir engineer has in any particular node of his reservoir model. You can get an idea of the range and breath of the computer simulation industry, a multi-billion dollar affair here.

My French fellow-bystander, to whom, this evening, I sent a high resolution photo of the cohort in which his son was marching, should remind himself, as he zooms in to try and find the face of his son amongst all the other faces, that although his son's face looks different to him, to the generals and the presidents, all the faces are exactly the same.


fdfs said...

Well... are you going to post the diary (modified for public consumption, of course) or not?

Don't tease us!

Jonathan Wonham said...

Hello Nick, sorry, not a very clear post that. I was rushing off on holiday. The suggestion was to look back in the archives. Anyhow, I'm going to update that blog with my thoughts during the most recent Bastille day events and I'll put a link to the archive as well.