Wednesday, April 28, 2004

Skippy the Kangaroo you'll never know.

This story reminded me of Skippy the Kangaroo and the TV series of my youth. It so happens that this TV series was a huge hit in France when I was young. But it was also the case in other countries like Australia, India but not in the U.S. So it is funny that while being a student in the U.S. and interacting with many different nationalities, one could automatically make reference to Skippy to certain people of some nationalities but not to the ones you were mostly interacting with all day long.

Tuesday, April 27, 2004

Always Be Closing

In a sort of way, this postmortem reminded me of Rendez-vous with Rama, or the desert of the Tartars. In either of these novels, the hero is waiting for something to happen and it never does. In the postmortem article, the sense is, you cannot rely on looking for funding while building your business, because it is a full time job which takes all your time away from the most important thing: building a business. On top of it, it has a very unattractive return on investment, a similar conclusion is reached in this book. The main lesson out of this is: when starting a business, make money from day one, you cannot afford not to.

Monday, April 26, 2004

45 Years in the making.

Talk about a project that would not die. The Gravity Probe B has finally launched after it was on the drawing boards for 42 years. This is no small achievement in an era of constant government budget cut-backs and so forth. Maybe someday, Dr. Everitt will write a book about it (more can be found here.)

Mona Lisa's Smile Fading

All is not well in the city of light, Mona Lisa's smile is fading. Could it be it has to do with the literally thousands of people taking a picture of it with a flash every single day ? Could it be that with the technology of digital cameras being sold en masse in the past four-five years, people do not care anymore about wasting films and therefore increase the number of photos of the paintings, thereby increasing the amount of light the painting sees every day ? Could it be that flashes used for digital cameras are more powerful (mostly because they can - the camera recharger takes care of the flash nowadays and are often used by camera users to recharge the whole camera making it an essential item - ? In other words, does flash used nowadays with digital camera exceed 12 watts or is the Musee du Louvre gift shop at fault for selling to thousands of customers paper-cameras that have essentially no UV-filters built-in ?

Wednesday, April 14, 2004

Wetting my interest.

This is an interesting product that Tyco/3M just came out with : the Novec 1230 does not seem to wet. This is interesting because the range of temperature where it is liquid goes from -109 C to 49 C. This is exactly the range of temperatures for electronics used for military or space systems. The latent heat of vaporaization at 49 C is 88 KJ/kg or about 20 times less than water, but water vaporizes at 100 C way too much for electronics parts. This could be an advantage as one could put electronics directly into the liquid and when it reaches 49 C, the liquid becomes two phase flow and gravity helping could be made to act as a thermosyphon.....

Friday, April 09, 2004

He took 60 years to fall into the sea....

The little prince has been found. Unlike what the news report say, I specifically recall listening to a person on TV who witnessed hearing a plane that day. It supposedly had difficulty after having gone though German flak.

Wednesday, April 07, 2004

On successful rapid prototyping

In a review on Serious Play, Dan Bricklin talks about how he, one of the inventor of visicalc (a predecessor to Excel), likes the book because of certain aspects that shows that eventually innovation is always about "...the customer's perceived mean-time-to-payback, not the innovator's speed-to-market, effectively determines which innovations will dominate their markets." This is absolutely true for all the software I am using like Matlab (which allows you in two lines to draw a curve), Python, etc... In a way, the customer feels enpowered into doing something "useful" and makes the product a success story.
What is very funny about this is the other study done by Kotteman, Davis and Remus (check [116]) that shows that when a group of MBA students using what-if tools like Visicalc, they were likely to do worse if not equally well than a group who did not have a what-if tool.

" [116] Jeffrey E. Kotteman, Fred D. Davis, and William E. Remus, specialists in business decisions, tested the ability of a group of students to control a simulated production line under conditions of demand with a strong random element. They add more workers with the risk of idle time on one hand, or maintain a smaller workforce with the risk of higher overtime payments on the other. They could restrict output relative to demand, possibly losing sales, if orders jumped, or they could maintain higher output at the cost of maintaining possibly excessive inventory.

[117] The subjects, M.B.A. student volunteers and experienced spreadsheet users, were divided into two groups. One group was shown a screen that prompted only for the number of units to produce and workforce level. The other group could enter anticipated sales for each proposed set of choices and immediately run a simulation program to show the varying results for projected inventory. They could immediately see the costs of changing workforce levels, along with overtime, idle time, and non-optimal inventory costs, all neatly displayed within seconds after entering their data. They had no more real information than the first group, but a much more concrete idea of the consequences of every choice they made.

[118] If all we have read about the power of spreadsheets is right, the "what-if" group should have outperformed the one with more limited information, unable to experiment with a wide variety of data. Actually the what-if subjects incurred somewhat higher costs than those without the same analytical tools, although the difference between the two groups was, as expected, not statistically significant. The most interesting results had less to do with actual performance than with the subjects' confidence. The "non what-ifs" rated their own predictive ability fairly accurately. The rating that subjects in the what-if group assigned to their own performance had no significant relationship to actual results. The correlation was little better than if they had tossed coins.

[119] Even more striking was how the subjects in the what-if group thought of the effects of the decision-making tools. What-if analysis improved cost performance for only 58 percent of the subjects who used it, yet 87 percent of them thought it had helped them, five percent believed there was no difference, and only one percent thought that it had hurt. This last-mentioned subject was actually one of those it had helped. Another experiment had an even more disconcerting result: "decision-makers were indifferent between what-if analysis and a quantitative decision rule which, if used, would have led to tremendous cost savings." In other words, the subjects preferred what-if exploration to a proven technique."49"

The most interesting part of that study was how the "what-if" group felt about their job of predicting the outcome of specific process. Most were so enamored with the fact they could play with it before making a decision that their confidence level was much higher than the other control group who did not have access to the what-if tool. They even showed in the original article that the what-if group was doing worse with time (not better). It would seem to me that one of the reason the what-if group is doing worse has a lot to do with the fact that they haven't learned the process, in other words, while they spent more time that the non-what-if group, they did not spend enough time to provide a significant statistics that would yield higher payback. This is one of the reason that in thermal engineering we need tools that do better than just give a max or min value temperature for design purposes. CRTech - article on Advanced multidisciplinary methods for parametric, optimization and reliability methods in thermal design and fluid flow design - for instance has some built-in tools that allows one to do monte-carlo on the system parameters in order to provide an idea of how wide the estimates are. These conclusions are rather annoying, it says that you can build a product that everybody thinks is worthy because it saves time and money when in fact it doesn't, the successful invention only boosts your ego/confidence.....

Messieurs les anglais, tirer les premiers...

On the site of the famous Agincourt battle, a new battle is heating up. One with windmills and History: it looks like the city of Agincourt is considering putting four large wind mills next to the terrain where the famous battle was fought. It is somehow an interesting fight. On the one hand, the city wants to be making money out of the wind turbines, on the other hand, they risk having less tourists thereby reducing tourist revenues. Since it was a British win, I can see how it has not been converted to a one of these fashionable history parks. The article says that up to 85,000 tourists come every year while each wind turbine would bring 5000 euros per month. The mayor of the city also says that he would rather see wind turbine construction than an increase the capacity of the nearby nuclear power plant. The trade-off seems pretty straightforward, the elected officials want to take the risk of a potentially drop-off in tourists in exchange of 20,000 euros per month while making the case that doing so will prevent a nuclear power plant from being built. Since a nuclear power plant produces about 1,400 MW-hr whereas a wind turbine produce only about 5 KW-hr or 0.005 MW or 1/280,000 of a nuclear power plant output, to the untrained eye, it really looks like it is really just a question of money... but that's just me.

Tuesday, April 06, 2004

Here is looking at you babe.

In a somewhat interesting experiment, one can see the green of the amazon through its reflection from the dark side of the moon. The earthshine spectrum is really the sun reflection on the earth then bouncing on the moon and bouncing back on earth (in a different spot). It is fascinating to be able to use the moon as a mirror....

Finding life with flowers in space

Recently, I was attending this course at College de France on observational interferometry. In it, Antoine Labeyrie was proposing the setting of mirrors along an hypersurface looking like a flower to build a Carlina hypertelescope. The word Carlina comes from this flower : the Carlina Acanthifolia.

It just so happens that Daniele Mortari proposed a flower constellation for spacecrafts flying around the earth. By enabling a baseline of 100,000 kms instead of the 150 kms now envisioned with Labeyrie's telescope, the flower constellation may have a bright future to find exo-planets. During this course, I met a fellow with interesting views on heterodyning.