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Cause of the second wave
When I saw the graphs about the clusters of COVID-19 infections in the past months in COVID-19, Tweede Kamer briefing, Update Tweede Golf - II, 29 sept 2020,
the presentation with the briefing to the Dutch parlement, it gave me some
ideas how the cause of the second wave of infections. This morning, a news report with a statement from the RIVM, affirmed these ideas. It
were primarily young adults (18-25 years) who going on holiday to Spain and
the south of France during August, who became infected in August. Then at the
start of September the infection spread further through parties and student
dorms. Through them also their parents got infected and from there is spread
further to the nursing homes. The number of infections has been doubling about
every two weeks. It is only the last two weeks that the number of hospital
admissions has been on the rise. This week is also was announced that about ten
thousand people died during the first wave. The average age was close to the
life expectancy.
NASCOM microcomputers
I discovered that on July 13, 1979, I visited the offices of NASCOM
microcomputers that developed and sold the Nascom 1 and 2 single-board computer kits. I had a random memory about bringing some eggs to an address while staying in
Watford. I found some note of this in
my diary V (written in Dutch) on page 72, where it mentions the name and the address of the company. (The
address is mentioned in an ad in Personal Computer World of October 1979.)
TSP
Last Thursday, I came along the article Computer Scientists Break Traveling Salesperson Record, which is about
the report A (Slightly) Improved
Approximation Algorithm for Metric TSP, which gives a slightly improvement
of the Christofides algorithm. In the discussion on Hacker News, I found a reference to
TSP-SA : Traveling Salesman Problem Solver using Simulated Annealing
Algorithm. I spend some time, using this for the program I wrote to find the best AKI Mupi
route. The solutions it finds are close to the shorters solution I found,
but not very close. In the discussion on Hacker News there was some confusion
about the presented result in the paper as it seems there are enough algorithms
know that find much better approximations than the one reported in the paper,
missing the point that the paper is about a theoretical result. Finding a
near optimal solution with a program is one things, but proving that a given
algorithm is always within a certain bound of the optimal solutions, is
something completely different.
Book
At 09:51, I bought the book De Arnhemse School: 25 jaar Monumental Kunst
Praktijk edited by Jonneke Fritz-Jobse and Ineke Middag, written in Dutch,
and published by Hogeschool voor de kunsten Arnhem in 1994,
ISBN:9074485081, from thrift store Het Goed for
€ 2.95.
Walking and some border poles
Conny and I went walking around the Groot
Bruning estate. Yesterday, it was sunny, but today the day started with fog,
which changed into a grey sky. We found may mushrooms of all kinds in the
forrest. The cows were still in the fields. Conny took a picture of the grey sky above the fields. Next we biked to the border,
to check if we missed some border poles in
some area. We found the following border poles:
The first two we had seen before, but the last was a new find.
Henk Helmantel
Conny and I went to Drents Museum to see the exhibition
Henk Helmantel
- Master Painter. We had tickets for a time-slot in the afternoon. So, we
first went to visit the Westerbork Synthesis Radio Telescope. We started at the parking place
of the National Westerbork Memorial and followed the path with models of the
planets (including the minor planet Pluto) and the sun on scale of their
(average) relative distances. This path ends at one of the end of the row of
radio telescope.
At the Henk Helmantel - Master Painter exhibition, I noted down the following
works in the order I saw them:
- Self-portrait in his studio, 2013
- Self-portrait, 1980
- Snowdrift on the dwelling mound of Westeremden, 1980
- View from the studio window, 1985
- Vegetable still life, 1985
- Still life with large roemer and quinces, 2011
- Still life with quinces and two bottles, 2019
- Still life, 1988
- Bronze bowl with three eggs, 2000
- Ode to the Father, the Son and the Holy Spirit, 2019
- The Cloister of Le Thoronet, 2001
- The choir of the church in Bozum, 2003
- The chapter house of the abbey of Le Thoronet, 2002
- Still life with a white bowl, 1991
- Still life with Roman glass and a Chines skirt on a Spanisch table, 2001
- Still-life composition with a homage to Kees Stoop, 2006
- Still life, 2000
- View of the South wall of the church of Oldenzijl, 2019
- The choir of the church of Oldenzijl, 2011
- Open window in the medieval stein haus in Bunderhee, Germany
- Two oranges, 2018
- Oranges and tangerines, 2018
- Fifteen intimate still lifes
- Onion still life, 2015
- Chestnuts on a red floor, 1998
- European archealogical glasse, 2003
- Chinese jar on top of a red cabinet, 2002
- Chinese cabinet with a open door, 2015
- Still life with Roman glass, 2004
- Chinese bronze objects, 1997
- The apostle James of a Gethsemane group, 2005
- Still life with tree pots from Europa, South America and Asia, 1992
- Mexican pot, 1994
- Still life with Drenthe archeaological finds, 2004
- Still life with a chinese Han vase and a bronze bowl with oranges, 2020
- Rembrandt chalk-glue pot (Phase 1, 2 and 3), 2000
- Window in the choir of the monastry church in Le Thoronet, 2019
- The Pieterskerk in Utrecht, 2014
- The east side of the gatehouse of Ammersoyen castle, 2019
- The hedgehog, 1988
- Chinese eggshell bowl, 1977
- Asparagus, 1988
- Belgian endive in a yellow box, 1992
- Still life with grapes, 2005
- Still life with pome granates, 2002
- Japanese doll, 1889
- Box from Taiwan, 1998
- Still life with worn family bible, 2004
- Still-life composition, 2003
- The most Dutch still life, 2019
- Bread baked in emden, 2007
- Book still life, 2020
- Still life with monastery bricks, 2005
- Large bronze water vessel, C.600 B.C., Shanghai museum, 2008
- In the kitchen of de Weem in Westeremden, 2020
- The cloister of sénanque, France, 2018
- Inauguration of Queen Beatrix April 30, 1980 in the Nieuwe Kerk, 1981
- The church in Leermens with thirteenth-century rood screen, 2011
- The north aisle of the church in Leermens, 2000
- The south aisle of the Romanesque monastery church in Jerichow, Germany, 2015
- Ambry of the church in Heideby on Gotland, 2015
- The choir of the church in Fide on Gotland, 2015
We also walked through the rest of the museum. We saw some drawings by
Charley Toorop, all
undated: Vrouw met kind, Drie mensen rond een tafel, Vier
mensen rond een tafel, Boer, and Vrouwfiguur. We walked
through the work Diasporalia by Koen
Theys.
On the way home we went to the village De Kiel to visit the point where seven marken are joined. In 2004 a new stone was placed at the location where
the original marke stone used to be. During the French period, there were no
farmers who wanted to claim the area, which was surrounded by seven marken,
namely: Westdorp, Ees, Odoorn, Sleen, Zweelo, Westerbork and Rolde. A land
surveyor from the Land Registry under the command of Napoleon divided the land
among the seven surrounding marken. The seven border lines are still visible
in the landscape. The road is on a crossing of six roads, which are on six of
these border lines.
Visting city center
It is the first time in at least a month that I visited the city center. At
Fotogalerie Objektief I saw the exhibition
Beautiful world with photographs by Donny Scholten-Coelet and at
Concoria I saw the exhibition Wayne Horse - May all your dreams come true.
At 15:38:21, I bought the book Veldnamen in Enschede written in Dutch
and published by Uitgeverij Van de Berg in 1992,
ISBN:9070986888, from bookshop Broekhuis for
€ 19.95. Alongside the book also a set of maps.
PARR books
I have been working on a program to generate books
with PARR patterns. Nowadays, there are many
sites that can print books on demand with all kinds of options with respect to
quality of the paper and means of binding. All you need to provide is some PDF
files. I spend some time figuring out if I could use (La)TeX to generate a PDF. It proved not so easy, as I wanted to have one
PARR pattern on each page, exactly aligned. So, I decided to use
PostScript and convert
it to PDF. (There are tools for combining PDF files.) The program tries to generate an interesting set of PARR patterns (for
a given number of lines and points). It does this by avoiding patterns that are
symmetric and combinations of patterns that are very similar. It also tries to
find a printing order in which similar patterns do not appear close to each
other. Everytime when the program is ran, it generates a new set of PARR
patterns.
This months interesting links
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Sunday, October 18, 2020
