Previous Up No next

Diary, December 2002

Sun Mon Tue Wed Thu Fri Sat
  1   2   3   4   5   6   7
  8   9  10  11  12  13  14
 15  16  17  18  19  20  21
 22  23  24  25  26  27  28
 29  30  31

Monday, December 2, 2002

Turning around a gas giant

Today, I read this article about the discovery that planets may form quickly. All exoplanets found so far, are rather large, and much closer to their sun than the large planets in our solar system. The idea of the Earth circling around such a gas giant never crossed my mind. I was thinking about what kind of atmosphere that would imply. It would at least mean some very cold period returning every so many days whenever the Earth would be in the shadow of the gas giant. And Also every round trip a time that there would be no darkness, whenever the Earth would be in from of the planet. I even wondered what would give more light: the sun or the gas giant, and what that would imply for the temperature change.


Site being blocked (Cont'd)

The last two days of November this web site was being blocked by my provider. I have decided to reduce the size of my web site a little. I also have decided to replace all inline images by links. This will make my site even more a "text-only" web site. But I think it will greatly reduce the amouth of traffic, as I guess that maybe 80 percent of the hits are accidential visitors, that arrived at one of my pages through a search engine, and who will immediately click on to the next site. These are typically not the people that will take time to investigate every link to see if it points to an interesting images.


Tuesday, December 3, 2002

Broken traffic light

Our city government has been advertising their web site for public services with messages that if you find some hole in the road that you can contact them. This morning, I decided to report a broken traffic light through this site. It was red light of traffic light for bikes with the number 22 at the crossroad at the Westerval where the Parkstraat goes over into the Wethouder Nijhuisstraat. I wonder how long it will take before it is repaired.

Wednesday, December 4, 2002

It is repaired

This morning, the broken traffic light was working again. Now I wonder how many people reported it broken before me, as I can hardly believe that they responded so quickly.

Artificial brains

It seems that Kwabena Boahen and his group at the University of Pennsylvania are working on developping artificial brains. Interesting stuff they are doing.

Thursday, December 5, 2002

Triangle grid (Cont'd)

Sometimes, I am really surprised about the depth of detail in certain apparently simple structures. First of all, I thought about another characterisation of sets of triangles. A set can be called elementary, if there is no subset of triangles which also can produce some pattern.

Then this afternoon, I was thinking how in some sets it must be possible to invert just a single point of a pattern to change the pattern in another pattern that can be made with the set. This made me think about graph where each vertex represents a pattern, and each edge a single value inversion. The interesting question of course is whether this graph would be total connected or be partitions in a number of connected subgraphs. You could also think about other interesting properties about these kind of connection graphs. (to be continued...)

Friday, December 6, 2002

Barely visible snow flakes

Around half past one in the afternoon there were some barely visible snow flakes in the air. And that is all we are going to get, because the wind will blow dry cold air from the East for the coming days. It is late this year. Normally we get the first signs of snow in November.

Hexagon and square grids

In a triangle grid you can flip a single value in a pattern, if there exists two hexagons (made out of six triagles) which have the same value on the outside but a different value on the inside. This morning, I realized that the triangle grids can be mapped on hexagon grids. Except from symmetries, there exists only one mapping of each set of up and down triangles onto a set of hexagons. There are however, far more possible sets of hexagons. 264 to be precise.

Next, I had to think about mapping a triangle grid on a square grid. It appears there are as many sets of squares (labelled with 0 and 1) as there are sets of up and down triangles (because 24 = 23 + 23). For each set of up and down triangles, there are three ways to map them unto a set of squares, everytime by combining an up and a down triangle into a diamond. This leads to the observation that some sets of squares might be equivalent with each other. Yet, I think that there are also sets of squares that are not equivalent to any set of up and down triangles, although I have not find an example yet. (To be continued...)

Tuesday, December 10, 2002

IQ test

I came along the IQ test from EMode and could not resist answering the 40 or so questions. The result, not very surprisingly, said that I am a Visual Mathematician with an IQ of 131. My score could have been higher if it was corrected for the fact that English is not my mother tongue. There were some questions that I did not feel sure about, because I did not fully understand the meaning of all the words. Of course, I was smart enough not to request for the full report, which costs about 15 dollar. Anyway, this is not even a good IQ test, as it does not have any time limit. You could spend a whole afternoon answering the questions. Any serious IQ test puts a time limit, such that you would have barely time to answer all the questions. Or it would measure the time you spend on each question. With a computer program that would be possible.

What is worse is that this site promotes the idea that the ideal partner would be someone with the same intelligence profile as yourself.

Wednesday, December 11, 2002

Steven J. Byrnes

Yesterday, the Siemens Foundation announced the national winners for the Siemens Westinghouse Competition. Steven Byrnes won the largest grand for proving a poset theorem based on the Chomp game. This is not the first time that he wins some price. Already in 2000, he solved Corner Problem 2000-4 from Mandelbrot Competition. But what is more important, in June this year he was also on of the five winners of USA Physics Olympiad Team. There it says about him: Junior, Roxbury Latin School, Boston, Massachusetts. Steven is a mathematic scholar, plays blues and jazz piano, sings, and is a member of the cross-country team. Steven lives in Lexington, Massachusetts. The site also gives a more extensive biography. See also this page which has a picture of him. Another picture can be found in an ASP news item. I think we will hear more about him in the coming years.

I still haven't found anything on the theorem and the proof of it. Apparently, this is not a very interesting subject for the general public.


Thursday, December 12, 2002

Inpainting algorithms

Today, I came across some pages presenting algorithms for inpainting damaged spots on pictures. One of the pages also showed how the technique can be used to enlarge pictures and still make them look sharp, just like the S-Spline program. Actually, these techniques could also be used for image compression. It simply comes down to picking a number of points that together with the reconstruction algorith would reproduce the original images with the desired quality. Finding the minimal set of points is a very complex problem, but I expect that some heuristic algorithms could come up with a solution close to optimal solution. Still decompression is rather expensive with this technique, much more expensive than currently used decompression methods. It is also likely that the algorithms described here will be used as a post-processing step for currently used decompression algorithms.

x86 versus PowerPC: backwards compatibility

Today, I read a story about MorphOS. This talks about microkernel versus macro kernel. Most PC are using the x86 type of processor of which the Pentium 4 is the last version in a long line of processors which were backwards compatable. Backwards compatibility is needed to still be able to run programs that worked on the previous version. Virtual memory management was only added in the 80286 (if I am not mistaken). But because backwards compatibility was required, context switches became rather expensive. The PowerPC was designed with virtual memory management from the start. For this reason, context switches are much faster. Context switches make communication between processes slower. For this reason, operating systems deployed on x86 processors (such as Windows and Linux) implement the whole operating systems as a single process. They make use of a macro kernel. You could also divide the kernel up into many smaller processes. This leads to microkernels, where there is one very small process surrounded by a host of processes which do the real work. The small process (the microkernel) only responsability is to keep all the other processes running. (A good example of a succesfull microkernel operating system is QNX.) Microkernels have many advantages, but speed is a big issue if the processor does have slow context switches. That is why you do not see them on x86 processors.

Again, a good example of legacy (having to maintain backwards compatibility) forces the use of an inferior kernel design to be used in competitive operating system. This law seems to operate on many levels in hardware and software design. One of the reasons that the PowerPC architecture never became mainstream is that it could not run applications developed for MS-DOS straight away. One could even state that the real cause behind this was the development of Closed Source applications. In fact one could even argue that the "capitalist" model of developing software, aggrevates the problem of legacy, because software development companies having to defend their market share will prevent the adoptation of better technology in favour of the existing technology.

Friday, December 13, 2002

Andy having a good memory

Yesterday evening, I attended a parents meeting at the Klim Op, where Andy goes every weekday. His speech therapist showed me how she managed to test his ears without him even suspecting that he is being tested. First she had to make him used to having a head phone on. Then she made up this game where he has to put a ring on a rod everytime when he heard some sound. When could play the game, she could start measuring. So far, she has measured half of the tones she needs to measure.

I also heard that Andy has a very good memory. The first thing in the morning is that they sit in a circle and during this time that days schedule is put on the board with pictures and pictograms. Every day somebody else has to take of these, once the activity is over. Andy is the only one who never forgets this, and even if it is not his turn, he will start pointing to the board when the others forget it.

Steve J. Byrnes (Cont'd)

It looks like Steve also joined MOP 2001 (very good and funny site). I also discovered that already in 1999, he solved several of the problems from the Mandelbrot Competition. I also found a dealing about the analysis of the Chomp game. The page also has a link to an email from Steve to the author of the game which makes clear that Steve worked on the problem this summer. I also found a nice Java Applet that allows you to play Chomp.


This evening, I checked the amouth of traffic this web site generates. It is about 30.7 Mbytes per day produced by an average of 2896 hits per day. The average size of each hit is 10.5 Kbyte. Compared to last month, this is a reduction of 12% with respect to the number of hits, and 36% with respect to the volume. It seems that my approach is working.


Saturday, December 14, 2002

Mathilde Willink

This afternoon, I happen to see some fragments about a film about Mathilde Willink made by Jasmina Fekovic and Eddie van der Velden. It is already more than 25 years ago that she was found dead with a bullit in her head.

Some links:

Wednesday, December 18, 2002

A little snow in the air

Around a quarter to two in the afternoon, there was some snow in the air. The flakes were a little bigger than on the sixth, but it lasted for barely ten minutes and it was far to warm to let any snow stay on the ground.

Saturday, December 21, 2002


Today, Annabel got her first swimming diploma. There were thirty children joining in the test, and they all passed. Not that it is not a serious examination (several times, some of them were asked to do something again, because they did not follow the rules exactly), but they had been screened on for hand to prevent embarrisment before family and friends watching the examination. As the last part of the examination, they had to keep their head above the water for thirty seconds using their legs and arms, while being in a vertical position. Everybody joined in the final countdown of the last ten seconds, and gave them an applaud for their achievement.


Monday, December 23, 2002

Gouden Loeki 2002

Today, we received a paper of the "Gouden Loeki 2002" election, which is an election for the best television commercial shown on Dutch television. You are asked to send in your top five from the selected 36 commercials. If your top five matches the final top five you have a chance of winning a trip for two persons to Rio de Janeiro. But there are 45.239.040 ways of selecting a top five from a given set of 36 items. It seems that the chance that but one persons answer match the final top five is rather small (with a population of 16 million people in the Netherlands) if all commercials are as popular. I wonder what the chances are, if some commercials are much more popular than others. Interesting question.

Tuesday, December 24, 2002


This evening, Annabel and I went to the Christmas night service of our church. Li-Xia stayed home to watch over Andy. This is the first time for Annabel and for me it is also some years ago that I went. On the invitation there was a request to bring some food for the asylum seekers that are staying in Enschede. Then also some young people suggested that we should also collect toys for the children. Thus we took a bag with things with us. When we arrived at the church I started to unpack the bag. And out of it came some toys that I had not seem for a long time, almost forgotten that we had them. Toys that Annabel and Andy played with many years ago. Suddenly, these toys felt very dear to me, because of the memories that they brought back. Almost with tears in my eyes, I layed the toys between the all the others. It was almost like I gave a part of myself away. But is that not what Christmas is really all about?

This months interesting links

Home | November 2002 | January 2002 | Random memories