Friday, July 30, 2004

Updating one's belief

This type of approach is very much needed in the area of engineering and science I have been working in. Yet I have never been acquainted to this technique before in a formal way: How different models can be compared over experimental data. Here is a view of Bayesian approach in the nuclear world (dosimetry or scram rate at plants.) In many cases, while you think you are building a theory with some modeling, what you are in fact doing is applying some type of belief in a model and hope the data confirm it. A pretty specific example is that of criticality computations in nuclear engineering. Criticality computation is a way to assess whether a certain amount of nuclear material can become critical (i.e. not safe) and yield consideration of the health of the people surrounding it. These computations are performed using Monte-Carlo codes or deterministic tools, and yield one number that is expected to be less than 1. Since material assemblies generally have many different constituents and have physical measurements with some uncertainties, the exercise is always bound to be a sensitivity analysis which can be very cumbersome. Some people try to develop models so that one can get rid of the multidimensional sensitivity studies but always end up having to convince other folks in the nuclear engineering community that their model is the better. Maybe this bayesian approach could help in raising the belief of others.

Will the car as a service be chinese ?

When I was talking about "car as a service", I did not realize that other people were thinking similarly. Take the comment of Philip Greenspun's Weblog: on the $ 3000 chinese car.

Other quotes I like

Taken from Bill Clementson's Blog, or Paul Graham's book:

"Ugly and imaginative solutions have something in common: they both break the rules."

"Technology often should be cutting-edge. In programming languages, as Erann Gat has pointed out, what 'industry best practice' actually gets you is not the best, but merely the average."

"Everyone knows it's a mistake to write your whole program by hand in machine language. What's less often understood is that there is a more general principle here: that if you have a choice of several languages, it is, all other things being equal, a mistake to program in anything but the most powerful one."

"If you want to make money at some point, remember this, because this is one of the reasons startups win. Big companies want to decrease the standard deviation of design outcomes because they want to avoid disasters. But when you damp oscillations, you lose the high points as well as the low. This is not a problem for big companies, because they don't win by making great products. Big companies win by sucking less than other big companies."

Thursday, July 29, 2004

Are you bored with your job ?

I just read great hackers. I liked the quote:

"The distinguishing feature of nasty little problems is that you don't learn anything from them... It's more a question of self-preservation. Working on nasty little problems makes you stupid. Good hackers avoid it for the same reason models avoid cheeseburgers."

If you look back at what you have done in the past six months, do you believe you have been working on nasty little problems ?

Bayesian statistics

Here is a good introduction to Bayesian Statistics and how it can be applied in physics or engineering.

Wednesday, July 28, 2004

Grand Challenge Course Plotter

Here is the course plotter for the DARPA 2004 Grand Challenge. Interesting ?

Why doing complex things require that you be administratively lightweight.

John Wiseman picked a good quote from Paul Graham in this quotarama on why doing designing complex projects require that you be administratively lightweight. I would submit that the reason people need forms to fill out is clearly related to the size of the organization. Past ten people, I have noticed that administrative processes need to be put in place in order for people to be treated fairly.

Mystery Animal, Really ?

This is not a mystery animal, people. It's a hyena.

Wednesday, July 14, 2004

Is this our future ?

I Know I talk a lot about the sleeping industry, but I think taking a nap is not a really good solution. What about sleeping better during the night ? wow what a concept.

Monday, July 05, 2004

Titan, Cassini and JIMO

The new first pictures of Titan tells us how much we don't know bout our own solar system. The reason the image is "blurry" is because we have not been able, from Earth, to divide a way to see through the atmosphere of Titan. For some of you that are not too aware of space missions, Cassini is in fact a pretty small probe. Currently NASA is taking input from the scientific community to get instruments (cameras,...) to go to Jupiter and its moons. JIMO is the acronym NASA uses for the Jupiter Icy Moons Orbiter. It is what we call a "paradigm buster" since instead of aiming for instruments that would require a few watts, the prometheus project would allow for kilowatts to be given out to the instruments and to the communication system. Instead of taking simple photos like the current mission to Saturn's moons, this spacecraft should allow for continuous HDTV-like transmission to the ground of what Europa looks like....

Thursday, July 01, 2004

That's what I am talking about.

This company has sensors that record data without touching the body: Nexsense wants a bite of the sleeping market. Please note that they do not say anything on HOW they get their measurements, vaporware anybody ?

Who's your friend ?

So the summer is just beginning and a heatwave already has already brought power cuts in Spain. But they have nuclear power plants there, so what happened ? Well I would not know, but could it have a relationship to the fact that they rely on these power plants for only 25% of their electricity needs ? Or could it somehow be related to the fact that the French CGT union decided to cut off a 400,000 Volts line from France to Spain yesterday yielding an unbalance in their power network "a la" 2003 Northeast blackout ? It must be an untenable position to be a politician in Spain, on the one hand you yield to your constituency and their misguided environmental decisions or you have to be dependent on ... the French, aargh.