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Diary, November 2015

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Sunday, November 1, 2015


Today, I celebrated my birthday with some family and friend. I opened the book Atlas of Finite Groups: Maximal Subgroups and Ordinary Characters for Simple Groups by John Horton Conway, Robert Turner Curtis, Simon Phillips Norton, Richard Alan Parker, and Robert Arnott Wilson. I received it on October 24, but I decided to open it today, because I had asked for people to contribute money for the book. I also got the book Genius At Play: The Curious Mind of John Horton Conway by Siobhan Roberts as a present. Annabel gave me some tea and her boyfriend gave me some home grown walnuts. Bert and Cornelise gave a jar with applesauce.

Saturday, November 7, 2015


At 12:58:46, I bought the book Het verhaal van De Stijl: van Mondriaan tot Van Doesburg by Hans Janssen and Michael White from bookshop Broekhuis for € 27.50. It is about the history of the De Stijl, Dutch for "The Style", also known as neoplasticism, was a Dutch artistic movement founded in 1917 in Amsterdam.

Sunday, November 8, 2015

Myst III: Exile

Yesterday evening, I started playing the computer game Myst III: Exile with a good friend. Today, we finished Amateria and got kind of stuck in Voltaic. It is a little more than ten years ago that I finished the game for the first time. It has been a long time ago that I had a look into it. Many things look familiar, but that does not mean that I remember all the puzzles. I did not look at any hints, until we had problems with the "lava room" in Voltaic, but the hints did not seem to fix the problem.

Friday, November 13, 2015

#DATA Hackethon - start

Some weeks ago, I decided to join the #DATA Hackathon organized by Innovalor and to work on the road maintenance case. Yesterday evening, I already spend some time downloading weather data from website of the Royal Netherlands Meteorological Institute. Also experimented with interpolation algorithm for MySample.


Enlisted myself and signed secrecy statement with respect to the data that will be provided. Played around with interpolation algorithm.


16:50 Analyse

Downloaded MDB Viewer to convert data to CVS files. Installed Open Office to inspect some Excel files. All very confusing


About 20:00, I decided to start writing a program to analyze the available data that I have exported in CVS format. The students on the team want to start to analyze the result of some excel sheets, which are in rather complex form. Around 21:25, I left for home.

Saturday, November 14, 2015

#DATA Hackethon - end

I arrived around 9:15 but only continued working on my program around 10. Around noon, I decided to stop and instead worked on some advice in which I suggested that deep machine learning techniques like TensorFlow might be usefull. I also spend some time talking with one case owners about these ideas. I also retracted from the contest. At 15:00, the 24 hours of the Hackethon was over and the teams started to give their 5 minute presentations. I left before the end of the event because of other appointments. The other three students working on analysing the data, won the first price. They focused on one highway and found some correlation plotting the data on a map and making some observations with respect to the direct vicinity of the highway.

Wednesday, November 18, 2015

Chinese Wooden Puzzle: White, orange, yellow, and red

In the past weeks, I worked on an alternative implementation for finding solutions to Chinese Wooden Puzzle resulting in a new program. The previous implementation would find a cell with a low number of piece placements and try all those placements. The new implementation each time selects a piece and tries all the placements for this piece. I tested this on the number of solutions inside a 8 by 10 frame using five of each of the white, orange, yellow, and red pieces. Today, the program found 23 solutions, which is three more than the 20 solutions found on Wednesday, May 21, 2013. In the coming weeks, I will continue verifying the earlier results with this new implementation, and I expect that it will find more solutions for the other problems as well. The 23 solutions are presented below:

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Saturday, November 21, 2015


At 13:08:57, I bought the bookDe Ontdekking van Moskou by Harry Mulisch, ISBN:9789023496960, from bookshop Broekhuis for € 19.90. This is a posthumous novel based on his third of six (or seven) versions of a novel that Mulisch never published. Parts of other versions have been published, which I compared in the past and about which I wrote a page in Dutch. I will have to update that page now with this newly published version.

Tuesday, November 24, 2015

Books and wet snow

At 17:10:09, I bought the following books from bookshop Broekhuis:

When I left the shop, there was wet snow falling from the sky. Also when I biked to my office in the morning, there was some very small wet snow, which stayed a little on my coat.

Wednesday, November 25, 2015

Turner and photographs

Today, Conny and I went to see the Danger & Beauty - Turner and the tradition of the sublime exhibition at Rijksmuseum Twenthe and the various places where the "Fotomanifestatie Enschede 2015" was held.

We first went to TETEM art space, were we looked at portret pictures of Koos Breukel. We also watched a documentary about the photo exhibition.

Secondly, we went to Rijksmuseum Twenthe. It was quite busy at the Turner exhibition, which also contained many related artworks from the same and later periods. We saw the following works by Joseph Mallord William Turner:

Furthermore, we saw:

At 15:31:48, we bought the book Gevaar en Schoonheid: turner en de traditie van het sublieme, ISBN:9789462620490, about the exhibition.

Next we walked to the city center. There we looked at photographs at Galerie Objektief with the exhibition Buried Dreams with photographs by Willem van Dijke, Galerie Beeld & Aambeeld with photographs by Alex Timmermans, and Concordia with photographs by Martijn van de Griendt.

Monday, November 30, 2015

Genius at Play

I finished reading Genius At Play: The Curious Mind of John Horton Conway by Siobhan Roberts, which I started reading on November 2, the day after I received it as a birthday gift. I very much enjoyed reading this book, first of all because of the subject of the book, John Conway, but also because of how the book is written.

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