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Diary, October 2020



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Saturday, October 3, 2020

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.


Tuesday, October 6, 2020

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.)


Saturday, October 10, 2020

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.


Monday, October 12, 2020

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 charity shop Het Goed for € 2.95.


Sunday, October 18, 2020

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.


This months interesting links


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