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In the past week, I tried to find out if there was an even shorter route to
complete the AKI MUPI route. I first tried
the TSP Solver
and Generator. Took me some time to generate a binary .tspt
file in the right format. The solver very quickly found a solution of more
than 28Km, not even close to the shortest route I had already found.
Next, I wrote a recursive back-tracking solver. It worked, but did not make
much progress, until I made some modifications that strongly reduced the
number of alternatives searched on every level. It did find a shorter route,
starting from home and visiting: C, E, I, Q, J, F, G, H, L, K, M, N, O, P, g,
a, Z, Y, W, X, l, k, j, i, h, f, e, d, c, b, V, U, T, S, R, B, A, D, and back
home where the letters refer to the points on the
map, I presented on June 27. Next, I
implemented a batch solver, which starts with a batch of 'smallest' possible
solutions and extends these in steps. With a batch size set to 5000, this
algorithm did not find any shorter algorithms. I added some of the output to
the source of the program.
Testing for COVID-19
Six foreign students of the University of Twente, who wanted to travel abroad
and were required to be tested, tested positive to COVID-19 to their surprise because they did not have any of the symptoms.
They are all living in the Hogekamp building that has about 450 rooms for
student of which about 80% are foreign students. Some foreign students from
China were surprised that not everyone in the building was required to be
tested. Although there is sufficient testing capacity, only people with
symptoms are advised to be tested. The official statement is still that it has
no use to be tested if you do not have any of the symptoms. The public health
organizations are doing contact follow-up on everyone who tested positive, but
it seems that those people are only advised to have themselves being tested if
they have or develop symptoms. I am a little worried that if six random people
test positive without showing any symptoms (and not knowing anyone who tested
positive) what that means to the number of (young) people who are now infected
without having any symptoms. It is possible that now a larger percentage of
people are infected without showing any signs of the infection due to seasonal
effects (such as higher vitamin D levels). I presume that testing is not
expensive compared to the possible economical costs in case another lock-down
is required when in the fall the number of people who develop serious symptoms
is on the rise again. Yet our government still seems not to attempting to
reduce the number of infections as much as possible, but to keep it below a
This afternoon, I went to the first Geluidsdrug event in Twente at Spacebar in the city center. I attended the workshop help by Error
Instruments and build a Data Synth noise generator. I also played a little in jamsession with
the Noise! synthesizer (which I build on May 29,
2016), the Greep Cluster (which I build on September 8, 2017), and Noise Engine 1 (which I designed and build on
May 26 this year).
I have been trying to reproduce the workings of the HEK program, which Peter Struycken used
in 1976 for designing a fence around the tax office in Zwolle. I started
looking into this, when I was informed about an attempt by someone else. The catalogue Beelden en Projecten gives a description of the algorithm along with some
drawings and graphs. The algorithm given some input parameters and a random
series, generates a series of angles and lengths. These angles and lengths
are used to generate a line drawing based on line segments. I wanted to
determine the multiplication factor that was used for the series of lengths
and I thought I could do this by reverse engineering the random series from
the series of angles (which could be derived from a design drawing). This did
not work as easy as expected. I came to the conclusion that the series of
angles are not used as absolute angles but as relative to the previous line
segment. A conclusion that seems to match with the description of the text. But
then it still did not work using the parameters in the text. To avoid errors in
the angles and lengths I had manually measured, I took a picture of one of the
design drawings and tried to measure the coordinates of the line segments more
accurately. Because that did not resolve all the issues, I decided to first
verify the algorithm with the graph showing the various input and output
parameters of the algorithm. Tonight, I concluded that the graph has an error
with respect to the line representing the random values. One of the points is
at 0.72 but it seems that according to the algorithm it should have been close
to 0.07, which looks like a simple displacement of period error, presuming that
the graph was hand drawn.
Just after midnight, Conny and I left on our
bikes to the road called Helweg to see if we could see comet Neowise. When on the Helweg we saw the comet. We stopped at a
crossing of the road and used a tripod to take some pictures from the comet and
also from the rest of the sky. I took a picture of Jupiter with four dots around it, the moons Europe, Io, Ganymede and
Callisto. I used the excellent website StellariumWeb for locating the comet and finding the
information about the moons around Jupiter.
At 17:30, I bought the book aki eindexamen fotografie 1999 written by
Rutger ten Broeke. edited by Marcel Vos and Tjipke Meijer, written in Dutch,
and published by AKI in 1999 from charity shop Het
Goed for € 1.50.
There are some flowers in our magnolia but only
a few have fully opened. The little chestnut
tree, that looked like it had died, has
started to grow some leaves. I try to water it regularly.
From 543 to 987
Today, it was reported that the number of COVID-19 infections in the Netherlands almost doubled from 543 to 987.
On a radio show, Ab Osterhaus pleaded for more testing and contact research. He says that
we, the Dutch government, do not have a consistent policy to eliminate the
virus. He feels the discussion is too much about the hospital capacity and that
we accept that the virus remains in the country. He argues that it is very
difficult to change the behaviour of people and that the government should
focus on testing and contact research to avoid the situation where another
lock-down has to be enforced, which will have serious repercussions on the
I received CampZone 2020 "Ærpane"
badge. Assembling was rather easy with the instructions. (I think, it would
be better to first plug in the small loudspreakers and then put them in
such that the wires are straight. I felt it was easier to first plug in the
flat cable before connecting the two printed circuit boards.) It took me a long
time to access the badge through the website. I installed the Brave web browser and added a rule for the USB drive. It only worked after a reboot.
Conny and I, followed a walking route
(description in Dutch) along historic places in Enschede following
the six wigbold markers, that marked the area
outside of the city of Enschede to which the city laws applied. Originally,
these were marked with field boulders. It is not known on which dates these
boulders were placed, most likely after Enschede received city rights around 1300, which were confirmed in 1325
by Bishop Jan III van Diest and henceforth allowed Enschede to protect itself
with a wall. In 1818, it was decided that the six stones would mark the border
between the city of Enschede and the county of Lonneker that surrounded it. In
1826 the boulders were replaced with Bentheimer stone posts. In 1934, Enschede
and Lonneker were joined and the border poles lost their function. The six
stones that are now placed near the original locations (but one is on the
original location) are replicas.
In the route also two old graveyards were included. Both graveyards were
outside of the city borders when opened, but are now well inside the city
borders. Both have been closed for almost a century, Both contain graves of
from important families of the textile industry that dominated Enschede.
Both graveyards fell into disrepair and some effort has been put into restoring
them. At the entrance of the the 'boeren' (Dutch for farmers) graveyard, there
is a sign signaling that alcohol and drug use is forbidden and that group
formation prohibited, but is seems that both are still taking place. In that
graveyard we also found a rather modern looking memorial stone for Tommy
Tattersall, who at the age of 17 died in 1887 after being kicked in his stomach
during a soccer game. Thomas "Tommy" Tattersall and his brother Stephen came to
the Netherlands with their parents in 1876. The family was included in the
Enschede upperclass, where they explained British soccer to their Dutch peers.
His father owned a factory supplying machines to the textile industry.
Saturday, three weeks ago, the memorial stone was revealed again after it was
being clean-up and recovered from some location outside of the graveyard. The
memorial has the form of a broken tree. We found some other examples of this
symbol on the other graveyard. We also found several graves with
an ouroboros and two
crossed, upside-down torches on it.
At 15:12, I bought the book De koningen van weleer written by Willem
Gijsen in Dutch and published by Meulenhoff in 1981,
ISBN:9789029010153, from charity shop Het Goed
for € 0.75.
Conny and I went to the Drenthe province. We first went to Drents Museum in Assen,
the capital of Drenthe. There we saw several exhibitions. First the exhibition Barbizon of the North: The Discovery of the Drenthe Landscape 1850-1950.
I found the following works notable:
- Jan van Ravenswaay, Landscape with cattle.
- Jan van Ravenswaay. View of Assen from Beilerstraat.
- George Loures Kiers. View of the Vaart in Assen.
- George Loures Kiers. View of the Brink in Assen.
- Egbert van Drielst, Drents Landscape, 1807.
- Albarta Ten Oever, Coach Passangers in Schipholt, 1806.
- Egbert van Drielst, View of Eext Village, 1810.
- Cornelis Bijlard, View of a tree and Bushes, 1836.
- Andreas Gerrit Jacobsen Roelofs, Little shed in Weerdingen, 1859.
- Willem Roelofs, The Dolmen of Tynaarlo, 1861.
- Alexander Mollinger, The Dolmen of Tynaarlo, 1861.
- Hendrik Dirk Kruseman van Elten, Hunnebed, 1982.
- Johan Driedé, Dolman at Eext, 1927,
- Johan Driedé, Dolman at Eext, 1927,
- Johan Dijkstra, Dolman at Loon, undated.
- Vincent van Gogh, The Peat Barge, 1883.
- Taco Mesdag, Landscape with Stacks of Peat and Three Women, undated.
- Reinhart Dozy, The OranjeKanaal, circa 1933.
- Reinhart Dozy, Village Celebration in Elp
- André Idserda, Church in Dwingelo, circa 1920.
- Geesje Mesdag-Van Calcar, View of the church de Vries, undated.
- Julius van de Sande Bakhuyzen, Landscape near Rolde, circa 1895.
- Anton van Rappard, Landscape near Rolde, 1882.
- Arie van der Boon, Fram in Rolde, undated.
- Louis Albert Roessingh, Windmill in Elp, undated.
- László Paál, Landscape near Beilen, 1871.
- Saskia Boelsums, Erica, 2019.
- Siemen Dijkstra, Morgenland - Rondveen Dwingelo, 1998.
- Berend Groen, Streamscape near Taarlo, 1998.
- Berend Groen. Old cementry near Loon, 1983.
- Reinder Homan, Tritypchi: Drenthe Aa River, 1995-1996.
- George Hendrik Breitner, Peasant Ploughing in Drenthe, 1885.
- Willem Hamel, Landscape with a Woman and a Goat, undated.
- Jozef Israës, The Drenthe Madonna, 1893.
- Max Liebermann, Preparatory Study for the Bleaching Ground in Zweerloo, 1882.
- Max Liebermann, Child under Trees (preliminary study for children playing), 1882.
- Julius van de Sande Bakhuyzen, Cow Herder Resting on the Bank of a Stream Bordered by Tree, undated.
- Arnold Marc Gorter, Country Road in Drenthe, circa 1900.
- Jan Meine Jansen, The Kamperzand Heath, 1934.
- Hendrik Willem Mesdag, Landscape near Vries with Peasant Ploughing, 1877.
- Alphonse Stengelin, Rising Moon, circa 1879.
From the exhibition Saskia Boelsums. I found the following works notable:
- Landscape #07, 2016/2017.
- Landscape #04, 2016/2017.
- Landscape #22, 2016/2017.
- Landscape #62, Bargerveen, 2018/2019.
- Landscape #50, Drenthe, 2018/2019.
- Landscape #11, Ameland, 2016/2017.
- Landscape #26, IJsselmeer, 2016/2017.
- Landscape flowers #07, Börkener Paradies, 2016/2017.
- Landscape #35, Bergerveen, 2016/2017.
From the exhibition David Schnell - Saison, I found the followin works notable:
- Stanze, 2018
- Niemandsland, 2017.
- Pascal, 2019.
- Kanal, 2019.
While walking through the rest of the museum, I also saw two works bij Jan
Sluijters: Baadsters in zee, 1995, and Damesportret. We also
the exhibition Wout Muller. At 13:39, I bought a round Goki puzzle and four cards with works on display at the museum
In the afternoon, we visted the superterp of LOFAR. We only saw it from a distance. I parked the car at the end of the
road Achterste Velddijk in Exloo and walked along this road where we
encountered the CS032 base station. We turned right on Beeksdijk. Along this
road there are two square pillars with some information about LOFAR. We walked
along base station CS001 and took the small path through the fields. When
coming close to base station CS011, we saw large flocks of goose take-off,
probably scared by our presence. We also found some mint plant, probably mentha aquatica. We crossed a bridge and walked till the next turn in the
path, which is the closest you can get to the superterp. But there was not
much to see due to lots of reed plants on this side of the superterp. Had we
continued, we could have walked 'through' base station CS017, but we returned
the same route we had come there. We collected some of the mint on the way
back. Conny took many pictures. When seeing
these pictures, I was a little suprised by the many contrasts between the
pictures she took.
This months interesting links
| June 2020
| August 2020
| Random memories