I write, therefore I am
With this variation on a famous statement by the philosopher Descartes, I would like to express that the act of writing about what happens in my life is important to me.
Maker Festival TwenteThis afternoon, Annabel and I went to the Maker Festival Twente. This year it was focused more on children than last year. At the stand of FabLab Enschede we met some classmates of Annabel. They we making wooden bracelet with a laser cutter. I also had one made with my name on it. Annabel has also looked at 3D printers. At the stand of LayaLay we found a small plug-and-play 3D printer of € 700 and at the stand of Make Block Shop we found a waterproof and somewhat flexible cup that was made by a 3D printer in approximately 51 minutes, which costs € 649.55. Annabel was impressed with the quality. Of course, we also spend some time at the stand of TkkrLab. Finally, I build a Noise! synthesizer at the stand of Reverse Landfill. This gave me some more experience with soldering. Some example sounds can be found on sound cloud.
Twelfth Dutch Kabuki dayAndy and I went to the Eleventh Dutch Kabuki family day held at Ronald McDonald Kindervallei in Valkenburg aan de Geul. Initially, I intended to go alone, but last Sunday, I told Andy that I was going, and when I casually asked him if he would like to go, he was very assertive that he wanted to go. When I asked him when was the last time we went there, he immediately said 2013, which is correct. So, I arranged that he could come as well. He behaved quite nice and enjoyed the the program they had for the children. There were many new families present, some with you children (who were not yet born on the last day) and some older children. Even one teenage boy, who just recently got a positive diagnoses. The highlight of the day, was the movie clip of the week of a 18 year old girl with Kabuki Syndrome. She is good at calculating the day of the week. She calculated the day of the week for my birthday this year correctly. I took the opportunity to talk with many of the new families.
But there was also some news on the scientific front. The group at the Academic Hospital Maastricht has now been recognized as an expert center for Kabuki Syndrome here in the Netherlands and there is a process of them also becoming partner of an European group of expert centers for the syndrome. Copies of the paper Body proportions in children with Kabuki syndrome were handed out. If I remember correcly, pictures of Andy were taken in 2013, and I assume that he is one of the 11 children with Kabuki Syndrome included in the study.
The most interesting news were the results from the growth hormone study. The results of the study are very positive. They found a one standard deviation improvement in the length and also the other body parameters (methabolic rate and non-fat tissue) improved. They are now going to request growth hormone therapy to be available for children with Kabuki Syndrome here in the Netherlands as only half a standard deviation improvement is sufficient. They did find that the normal test for the various growth hormone factors gave very conflicting results, not in accordance to normal measurements, but that non the less, all children in the study (even those that otherwise would not have been qualified for growth hormone therapy based on the factors) reacted positively to the therapy. Before it was reported that growth hormone therapy seems to have a positive effect on muscle tone, concentration, and intellectual abilities. In some cases it also seems to stabilize blood sugar levels. But this was not studied in this study and thus also not affirmed.
The Ego TunnelI finished reading the Dutch translation of the book The Ego Tunnel by Thomas Metzinger, which I started reading on April 25, the day I recieved it after I bought it secondhand on-line. Metzinger is a philosopher who work together with neuro-scientists and he is not afraid to talk about subjects that are controversional in science: Out-of-body experiences and lucide dreaming, both of which he has experienced them firsthand. Yet he is able to intergrate them with scientific findings. He explains that the experience of self is so strong because conscious states are transparent. We We do not see the model that our brain creates from the brain, but we directly experience the model. We cannot see the construction process (in our unconsiousness) because it is too fast and too robust. He makes a good case to this. I felt the last chapter a little weak, because it asumes that people have a free will, which seems not the case. Also I believe that most people are not able to grap and/or accept the reality that he is describing because too difficult to accept. And for this reason, I do not believe that we will go through the transformation that he is describing. To me, it seems that people are moving away from science more and more. The scientific reality is only understood and accepted by a small portion of society, because often it is counter-intuitive, especially with respect to consciousness and selfness.
BookAt 11:12, I bought the book Boezem by Edna van Duyn, Marinus Boezem, and Fransjozef Witteveen written in Dutch and English published by Art Books International Limited in 1999, ISBN:9789068682229, from charity shop Het Goed for € 6.50.
The Things Network nodeThe past month, I have become a regular visitor of TkkrLab, a local hackerspace. Today, there was an opportunity to build The Things Network node consisting of a RN2483 Low-Power Wide-Area Network chop and a Chinese Arduino Nano clone. One of the organizers soldering the RN2483 chip to the PCB for me. I did the soldering for connecting the Arduino Nano to the PCB. One of the organizers also helped me testing the unit and it seemed to work using the TTNMapper Andriod App. I did not have a laptop available, so I could not create a user account for myself. In the evening, at home, I got the node to work after having some trouble with getting ttnctl to run (got an x509 error on Windows XP), connecting to the Chinese Arduino Nano clone (required driver for CH340 serial USB chip), and getting Arduino IDE to compile ttnmapperarduino (had to move library files to the proper location). It also looks like the signal is only picked up by the gateway in the center of the city when I put the node outside in the backgarden. I saw four 'ping' messages come through as a proof that everything works. Now I have to find some interesting application for it, and also find out how I can process the messages using MQTT.
Street Tiling: Diagonal - CorrectedContinuing from my research on Street Tiling Patterns, I discovered that previous presented results are incorrect. I changed the program to calculate the number of diagonal sequences starting from the sequences with length three. To my surprise, I stopped very soon. While debugging, I noticed that there was a tile with two B's on the right, while there is non with two B's on the left, meaning that the elimination algorithm for removing tiles that can never occur, was incorrect. When I corrected the error, two more tiles were removed resulting in the set:
AA AA AB AB AB AB AD AD AD BA BA BA BA BC BD BD BD CA CA CD CD DA BD DA AA BA BC DE AB DA DG AD CD EA ED EF AB EA EG FA FD FA FG AB DA DE DE DE DE DE DG EA EA EA EA EA ED EF EF EF EF EF EG EG FA FA BD AA AB BA BC GH AB AB AD CD HA HD HA AA AB BA CA HI AB HA AB AD FA FA FA FD FG FG GH GH GH GH HA HA HA HD HI HI HI HI IA IA IA ID BD IA ID IA AB IA AA AB BA BC AB AD CD AB AA AB BA CA AB AD BD AB
But this did not effect the algorithm for finding all possible diagonal sequences. Next, I noticed that one sequence of length five being marked as impossible, was actually possible. This uncovered a huge bug in the algorithm for calculating impossible sequences. Now it no longer found impossible sequences with length five and the algorithm enumerating possible diagonal sequences returned many results. But I did find some diagonal sequences for which there was no next diagonal sequence. I changed the algorithm for finding impossible sequences such that it would not stop with length five. I made it search up to sequences of length 23. It found nine impossible sequences that all contain the subsequence "AHIFA". There are possible diagonal sequences that contain the subsequence "AHIFA". It is not possible to claim that these are all the impossible sequences, but there is reason to believe that this is the case. The sequences are:
DAAHIFAAB DAAHIFADEBA DAAHIFADEBD ADEBAHIFAAB BDEBAHIFAAB ADEBAHIFADEBA ADEBAHIFADEBD BDEBAHIFADEBA BDEBAHIFADEBDOn could capture all these sequences with the regular expression ([AB]DEB|DA)AHIFA(AB|DEB[AD]). Below a table given results with respect to the number of diagonal sequences. The first column gives the length of the sequences, the second column the number of diagonal sequences, and the third column the number of patterns that exist till and including this diagonal. The rest columns explain the relationship between the number of sequences and number of columns. For the columns with the number n in the header, the number in the row tells how many sequences are related to n patterns with the sequences. The numbers in the row add up to the number of sequences, while the numbers multiplied with the number in the header of the columns add up to the number of patterns.
l #dia #pat 1 2 3 4 5 6 7 8 9 ------------------------------------------------------------------ 3 3 3 3 5 6 6 6 7 12 12 12 9 30 30 30 11 68 69 67 1 13 178 210 150 24 4 15 483 636 354 105 24 17 1706 2684 1010 478 182 8 28 19 7452 13160 3582 2480 1086 160 144 21 35764 74566 13102 12242 7166 1320 1666 64 162 24 18
May 30: These results are incorrect!
BookAt 11:18, I bought the book Eindexamencatalogus 2007 / ArteZ Academie voor beeldende kunsten Arnhem written in Dutch published by ArteZ Academie voor beeldende kunsten Arnhem in 2007, ISBN:9789086900916, from charity shop Het Goed for € 2.50.
ArtI visited Rijksmuseum Twenthe. First I looked at the exhibition De Nieuwe Smaak (The New Taste). I liked the following works:
Next I saw the Thomas Gainsborough exhibition. I was not very impressed. The work I liked most is The daughters of the artist from around 1758.
From 12:01 to 12:17, I walked around The Rhythm Painter by Jaap Drupsteen. (impressions on vimeo.) After I looked around the rest of the museum, I came back and walked around from 12:38 to be another twenty or so minutes. In the rest of the museum, I liked:
At 13:07:20, I bought the book De Nieuwe Smaak. De kunst van het verzamelen in de 21ste eeuw edited by Josien Beltman written in Dutch published by Rijksmuseum Twenthe in 2016, ISBN:9789072250421, from the museum for € 2.00.
Next, while on my way to TETEM art space, I decided to visit Kunstenlandschap (Art and landscape). At Tetem, I saw the following works I liked:
Street Tiling: DiagonalIn the past week, I continued working on the program for Steet Tiling patterns with Wang tiles that I started developing on May first. This program first of all reduces the set of Wang tiles to those that can occur in combination with other tiles. This results in the following set:
AA AA AA AB AB AB AB AB AD AD AD BA BA BA BA BC BD BD BD CA CA CD BD DA DD AA AB BA BC DE AB DA DG AD CD EA ED EF AB EA EG FA FD FA CD DA DA DE DE DE DE DE DG EA EA EA EA EA ED EF EF EF EF EF EG EG FG AB BD AA AB BA BC GH AB AB AD CD HA HD HA AA AB BA CA HI AB HA FA FA FA FA FA FD FG FG GH GH GH GH HA HA HA HD HI HI HI HI IA IA AB AD BD IA ID IA AB IA AA AB BA BC AB AD CD AB AA AB BA CA AB AD IA ID BD AB
Next, I wanted to know if it would be possible to construct an algorith that would fill one quadrant of the plane with a 'random' pattern, by completing a diagonal at the time. It would be nice to know that if one has finished a diagonal, it is always possible to fill the next, without having to back-track to the current. We look at filling the fourth quadrant. We define a diagonal sequences of colours that can occur on a path that alternating goes up and right, starting with an up movement from the first colour to the second and ending with a right movement between the last two colours. This means that the sequences are always of odd length. I wanted to find out which sequences are not possible. For the sequences of length three this is rather simple to derive from the above Wang tiles. For example the sequence III is not possible because there is no Wang tile in the above set that has I in the left bottom, left top, and right top corner. The program found the following sequences of length five and seven that are also not possible (excluding sequences that contain a shorter sequences that is already not possible. There are no sequences of length nine that are not possible (presuming that they do not contain impossible sequences of length three, five, and seven. This gives some hope that it is indeed possible to implement a back-tracking algorithm that fills the quandrant diagonal by diagonal, not having to back-track to a previous diagonal if the impossible sequences are avoided when filling a diagonal. The sequences are:
BAABA BAABD BAAEA BAAEF BAAEG BAAFA BAAFG BAAHA BAAHD BAAHI BAAIA BAAID DAABA DAABD DAAEA DAAEF DAAEG DAAFA DAAFG DAAHA DAAHD DAAHI DAAIA DAAID ABABA ABABD ABAEA ABAEF ABAEG ABAFA ABAFG ABAHA ABAHD ABAHI ABAIA ABAID CBABA CBABD CBAEA CBAEF CBAEG CBAFA CBAFG CBAHA CBAHD CBAHI CBAIA CBAID EBABA EBABD EBAEA EBAEF EBAEG EBAFA EBAFG EBAHA EBAHD EBAHI EBAIA EBAID EBCBA EBCEA EBCEF EBCHA EBCHI FCAFA FCAFG FCAIA FCAID ADAAB ADAAD ADADA ADADE ADADG BDAAB BDAAD BDADA BDADE BDADG ADGDE AEAAB AEAAD AEADA AEADE AEADG CEAAB CEAAD CEADA CEADE CEADG HEAAB HEAAD HEADA HEADE HEADG AEGDE HEGDE AFAAB AFAAD AFADA AFADE AFADG BFAAB BFAAD BFADA BFADE BFADG IFAAB IFAAD IFADA IFADE IFADG AFGDE IFGDE AHAAB AHAAD AHADA AHADE AHADG AHAGH CHAAB CHAAD CHADA CHADE CHADG CHAGH AIAAB AIAAD AIADA AIADE AIADG AIAGH BIAAB BIAAD BIADA BIADE BIADG BIAGH AABABAA AABABAB AABABDA AABABDE AABABEF AABABGH AABDEBA AABDEBC AABDEBD AABEFCA AABEFCD AABGHEA AABGHED AABGHEF AABGHEG AABHIFA AABHIFD AABHIFG BABABAA BABABAB BABABDA BABABDE BABABEF BABABGH BABDEBA BABDEBC BABDEBD BABEFCA BABEFCD BABGHEA BABGHED BABGHEF BABGHEG BABHIFA BABHIFD BABHIFG DABABAA DABABAB DABABDA DABABDE DABABEF DABABGH DABDEBA DABDEBC DABDEBD DABEFCA DABEFCD DABGHEA DABGHED DABGHEF DABGHEG DABHIFA DABHIFD DABHIFG AADABAA AADABAB AADABDA AADABDE AADABFA AADABGH AADABIA AADADAA AADADAB AADADAD DADABAA DADABAB DADABDA DADABDE DADABFA DADABGH DADABIA DADADAA DADADAB DADADAD ABDABAA ABDABAB ABDABDA ABDABDE ABDABFA ABDABGH ABDABIA ABDADAA ABDADAB ABDADAD EBDABAA EBDABAB EBDABDA EBDABDE EBDABFA EBDABGH EBDABIA EBDADAA EBDADAB EBDADAD FCDABAA FCDABAB FCDABDA FCDABDE FCDABFA FCDABGH FCDABIA FCDADAA FCDADAB FCDADAD ADEBDAA ADEBDAB ADEBDAD BDEBDAA BDEBDAB BDEBDAD GDEBDAA GDEBDAB GDEBDAD HEDABAA HEDABAB HEDABDA HEDABDE HEDABFA HEDABGH HEDABIA HEDADAA HEDADAB HEDADAD AEFCDAA AEFCDAB AEFCDAD BEFCDAA BEFCDAB BEFCDAD CEFCDAA CEFCDAB CEFCDAD HEFCDAA HEFCDAB HEFCDAD IFDABAA IFDABAB IFDABDA IFDABDE IFDABGH IFDADAA IFDADAB IFDADAD AGHEDAA AGHEDAB AGHEDAD AGHEFCA AGHEFCD BGHEDAA BGHEDAB BGHEDAD BGHEFCA BGHEFCD AHDABAA AHDABAB AHDABDA AHDABDE AHDABEF AHDABGH AHIFDAA AHIFDAB AHIFDAD BHIFDAA BHIFDAB BHIFDAD CHIFDAA CHIFDAB CHIFDAD AIDABAA AIDABAB AIDABDA AIDABDE AIDABEF AIDABGH
These results are incorrect! read follow-up story.
BooksAt 11:47, I bought the following two books from charity shop Het Goed:
Wednesday, May 11, 2016
Versaille patternI got interested in Street Tilings when I saw the Versaille tile pattern. This is pattern that repeats every six unit squares in both directions (without shift). I used my program to calculate all possible patterns and it found 78 of which only five have the same ratio of tiles as the Versaille pattern (including the pattern itself, of course). The patterns are displayed below. The title specifies the number of tiles of each size from small to large. For the Versaille tile pattern this is "4,2,4,2,0". The patterns are sorted by title.
Monday, May 9, 2016
Sunday, May 8, 2016
Temperature swingLess than two weeks ago, the temperatures were very low for the time of the year. On April 26 the temperature reached below zero degrees Celsius and was at most nine degrees. On that day and two day before we even had some wet snow. Yesterday and today we had totally cloudless days and today the temperatures went up to 24 degrees. It seems that our small magnolia tree is not doing well as it seems that the new leaves has been damanged by the frost in the past weeks.
Street Tiling - Wang TilesIn the past week, I made some improvements with respect to the program that I wrote to generate Steet Tiling patterns. The latest version of the program can find all solutions up to an area of thirty in less than a day. I tried to add some more checks in the recursive back-tracking function, but it seemed that I hit some wall and that many simply made it slower. With each additional test to avoid parts of the search tree that are not going to find results, you also add some time to the execution of the function, adding a constant time to the total execution time. If a certain test is only effective in a rather small number of cases, this can lead to an increase in the total execution time. I thought about the idea to use Want tiles for the most restrictive case. I tried several coding methods. I came up with the idea to use the letters A to I to mark the unit squares of the tiles in the following manner:
A AB A AB ABC D DE DEF AB ABC DE DEF GH GHI
If you look at all the ways these can be layed on a square grid, than the following 86 patterns can occur on the squares made up of two by two unit squares:
AA AA AA AA AB AB AB AB AB AB AD AD AD AG AG BA BA BA BA BC BC BC BD CD DA DD AA AB BA BC CA DE AB DA DG AB DA AD CD EA ED AA AB BA BC BC BD BD BD BG BG CA CA CD CD CG DA DA DA DA DA DD DE DE DE DE CA EF AB EA EG AB EA FA FD FA FG FA AB BD CD GA GD GA AA AB BA BC DE DE DG DG EA EA EA EA EA ED EF EF EF EF EF EG EG FA FA FA FA FA CA GH AB GA AB AD CD HA HD HA AA AB BA CA HI AB HA AB AD BD IA ID FD FG FG GH GH GH GH GH HA HA HA HD HI HI HI HI IA IA IA ID IA AB IA AA AB BA BC CA AB AD CD AB AA AB BA CA AB AD BD AB
These are not exactly Wang tiles, because Wang tiles are labled on their edges, not their corners. But there are 28 different combinations of letters that occur on the edges, thus we could create an equivalent of 86 Wang tiles with 28 different 'colours' for the edges. This is a rather large number, and I thus thought about a way to create Wang tiles with less 'colours'. If one makes Wang tiles around the points where four unit squares meet, and use letters to indicate properties about the edges, I came up with the following set of 76 Wang tiles using nine 'colours' (0 and the letters 'a' to 'h'), where the order in which the 'colours' are give are top, left, right, and bottom side. Note that for every wxyz there is also a xwzy.
0000 0ada 0ae0 0bda 0bf0 0cda 0cg0 0dga 0dh0 0ega 0fga 0fj0 a00e a0ad ab0b ac0b ad0b af0b b00f b0ad bab0 bb0c bbc0 bc0c bd0c bdb0 bec0 bf0c bgb0 bhc0 c0ad cdb0 cec0 cgb0 chc0 d0ag dab0 db0b dbc0 dc0b dd0b ddb0 dec0 df0b dg0b dh0b e0ag eb0c ec0c ed0c ef0c eg0c eh0c f0ag fdb0 fec0 fgb0 fhc0 gab0 gbc0 gd0b gdb0 gec0 gf0b gg0b gh0b hab0 hbc0 hd0c hdb0 hec0 hf0c hg0c hgb0 hh0c hhc0
I did search for algorithms or programs for analyzing Wang tiles, but I failed to find any. Last week, I came across a copy of the book Shadows of the Mind in which there is some reference to tiling the plane with copies from a set of polyominos.
Thursday, April 28, 2016
Trip to China 2010
-- contact -- Frans
My life as a hacker
The Art of Programming
HTML to LaTeX
eXtreme Programming Hamilton cycles