2020-05-01 (Sköna maj välkommen!)

Today, I learned about:

Nothing is like it used to be. Yesterday was April 30, the day that Sweden is used to celebrate the arrival of Spring with various fun events during Valborgsmässoafton (Walpurgis night). The whole story started already during the 8th and 9th century in England. You can read more about it in reference #1 below.

One popular tradition on that day in Gothenburg, Sweden’s second biggest city, is the Cortège, when the first-years students at Chalmers University of Technology give their review of the events of the preceding year in a carnival-style parade. The header photo today was taken during the Cortège in 1977. I had the pleasure of participating in it two years earlier and I must admit it was really a treat.

Another tradition on that day is to light bonfires as a way to keep the evil spirits away, and especially in the old university cities of Uppsala and Lund people gather to hear the students choirs sing their traditional songs praising Spring.

But, nothing of that sort happened yesterday. The COVID-19 pandemic impeded all those traditions to be celebrated once more. It was therefore a pleasant surprise what Radio Sweden had in store for us.

The classical music channel P2 had invited its listeners to contribute in a special way, by recording their voices and faces when singing the traditional song Längtan till landet (I am longing for the countryside). See reference 2 below for the P2 page and reference 3 for the video with the song.

And if you want to sing along with all the other 707 singers in the choir, here are the lyrics:

I dedicate this post to my dear old friend Bosse, who took so well care of me from the moment I first arrived in Brazil. He loves this kind of music, his idol is the late Jussi Björling, need I say more? For those who do not recognise that name, let us compare him to later day tenors like Luciano Pavarotti, Plácido Domingo, and José Carreras. See also reference 4 below.

That’s what I learned in school !


1: Walpurgis Night

2: Hela Sverige sjunger in våren!

3: Hela Sverige sjunger i P2:s valborgskör

4: Jussi Björling

*: What did you learn in school today ?

2020-04-01 (Corona relief ?)

Today, I learned about:

I just heard an interesting piece of news. It seems that the WHO (World Health Organisation) and the WCSF (World Cruise Ship Federation), which has all the big cruise ship companies among its associates, are close to conclude a deal which may be a big relief for those people who need to be treated because of COVID-19, the corona virus pandemic that is keeping the world at a still.

Two cruise ships exploring the Baltic Sea, photo taken in July 2019.

The idea is that since WCSF cannot keep their ships running normally due to all docking restrictions, they want to show the world that their ships are not only meant for luxury cruises for those with plenty of money, but also for normal people who never would have a chance of coming close to such a ship. So instead of trying to find space for treatment in the saturated, normal health care system and its hospitals, the ships would be anchored on a sufficient distance from land to not disturb life on shore, and yet offer plenty of rooms and beds for the necessary health procedures and recovery.

Keep your eyes and ears open, the official announcement should come any minute now.

The idea of using a ship as a hospital is not new, there are indications that the Greek had some already in ancient times. The British included a hospital ship in their Navy in the 17th century, many hospital ships were of course used during World Wars I and II, and just two days ago, the USNS Confort docked in New York City to help treating corona patients there. See also references #1 and 2 below.

USNS Confort, photo by Spc. Landon Stephenson on April 11, 2009

That’s what I learned in school !


1: Hospital ship

2: Everything you need to know about the USNS Comfort, the giant hospital ship in NYC

*: What did you learn in school today ?

2020-03-24 (40 anos!)

Today, I learned about:

Exactly four years have gone since I wrote a post about when I first set foot on Brazilian soil. That time, 36 years had gone since that historical step, 2016-03-24.

And here we are again, four years older, and maybe even wiser! So today makes 40 years since I came to Brazil as a trainee engineer, who would think that I would end up here? But here I am, and frankly speaking, I cannot complain! Life has been tough, but I have had my golden days, as well. And to celebrate those 40 years, what could be better than the Brazilian national drink, caipirinha? It is so easy to make and it is refreshingly tasteful. Look at another post, 2016-02-14, for the recipe and a photo. Saúde, cheers, skål !

All about COVID-19

I know that many of you are exactly in the same situation right now as I am, locked down at home, waiting for that nasty corona virus to disappear. The Chinese e-commerce giant Alibaba has elaborated and published a comprehensive story about what it is, how to treat it, etc. In ref. # 1 below, there is a copy of their report, it is really worth reading! And if you are so inclined, Alibaba is asking for volunteers to help translate the book into Korean and European Portuguese. More about that in ref. # 2 below.

That’s what I learned in school !


1: Handbook of COVID-19 Prevention and Treatment

2: Jack Ma Foundation shares coronavirus; prevention handbook

*: What did you learn in school today ?

2020-02-29 (Leap day!)

Today, I learned about:

Exactly four years have gone since I last wrote about what a leap day is, 2016-02-29.

And here we are again, four years older, and maybe even wiser! I was thinking about the poor guy that was born on 1896-02-29. He celebrated his birthday on the correct date of the year only when there were eight candles on his birthday cake. How come? Well, as you know a leap year normally happens only once every four years, but when the century is on its first year, then it must also be evenly divided by 400, i.e. 1600, 2000, 2400 etc. But then, he knew that if he lived that long, he would still celebrate it on the correct day with 12, 16, 20, 24, … candles!

‘Can you use an hourglass’?

Finally, here comes the solution to the riddle posted back in 2019-12-31:

You start with two loaded hourglasses at the same time. After 7 min, when the small hourglass is done, you turn it over and restart it.

After 11 min, when the big hourglass is done, you leave it as it is. But now you turn over the small hourglass, which has had a second run of 4 min, and let it run for the third time until it stops.

Voilà, you have now accomplished the task!

That’s what I learned in school !


*: What did you learn in school today ?

2020-01-09 (4 years!)

Today, I learned about:

Exactly four years have gone since I wrote my first post in this blog, 2016-01-09. It was really short, talking about potatoes, but it gave me the kick to want more. The story about why I started the blog was published on 2017-01-14.

Thank you all who follow my blog and write me with suggestions about what to publish in future posts!

A hint to ‘Can you use an hourglass’?

In my most recent post, on 2019-12-31 , I gave you a problem involving the use of two different hourglasses, with capacity of 11 min and 7 min, respectively, and asked you to measure exactly 15 min.

If you are still fighting with the solution, let me give you two important hints:

11 – 7 = 4


15 – 11 = 4

Can you solve it now?

A complete solution will be presented in my next post.

That’s what I learned in school !


*: What did you learn in school today ?

2019-12-31 (Réveillon!)

Today, I learned about:

Once again, it is that day of the year when we reflect over how the year behind us was and make our predictions and wishes for the year to come.

One important piece of news during 2019 was that researchers at my alma mater Chalmers University of Technology, Gothenburg, Sweden, led by professor Kasper Moth-Poulsen reported that they have developed a molecule, that is able to capture the sun’s rays, store it as chemical energy for up to 18 years, and retrieve the energy and convert it into heat when needed.

The following graphic shows how it all works:

It all starts in the upper middle section of the sketch. The solar reflector (SOLFÅNGARE) placed on the roof of a building captures the sun’s rays. The parabolic section concentrates solar energy and transmits it to the liquid in the tube in the center of the solar reflector. From there, the cold liquid, now containing stored chemical energy, is sent to an energy storage (ENERGILAGER). It can be stored there for up to 18 years! When we need to heat up our house, we simply let some of the liquid out from storage, run it through the catalyst (KATALYSATOR), thus obtaining a hot liquid without any stored chemical energy. Experiments have shown that the liquid with released heat can have a temperature that is 63 °C higher after the catalyst in relation to before! The hot liquid then goes into the normal heating system of the house, e.g. the radiators (ELEMENT I HUS) in the various rooms, heats up the ambient, and then the now cold liquid goes back up to the roof to capture more sun rays. Graphic made by Yen Strandqvist.
The leftmost photo shows the parabolic solar reflector with the liquid tube in the center. To the right is the inventor of the material, professor Kasper Moth-Poulsen, securing a small sample of the miraculous liquid. All material has been extracted from Chalmers Magasin no. 1 2019, text by Karin Aase and photos taken by Oscar Mattsson and Johan Bodell.

References # 1 through 4 below contain more material if you are interested in further details.

Can you use an hourglass?

According to Wikipedia: “An hourglass (or sandglass, sand timer, sand clock or egg timer) is a device used to measure the passage of time. It comprises two glass bulbs connected vertically by a narrow neck that allows a regulated flow of a substance (historically sand) from the upper bulb to the lower one. Typically the upper and lower bulbs are symmetric so that the hourglass will measure the same duration regardless of orientation. The specific duration of time a given hourglass measures is determined by factors including the quantity and coarseness of the particulate matter, the bulb size, and the neck width.

So you think are smart? Then show it now! We have two hourglasses like the ones shown above. The bigger ones completes one cycle in 11 minutes, the small one in 7 minutes.

Question: Using a combination of these two hourglasses, you need to measure a time lapse of exactly 15 minutes. How would you do it? (Solution to follow in the first blog post of 2020.)

I wish all my faithful blog readers a HAPPY NEW YEAR!

That’s what I learned in school !


1: Extract from Chalmers Magasin nr 1 2019 (article in Swedish)

2: An energy breakthrough could store solar power for decades

3: Storing the energy from the sun for decades

4: Liquid sunlight creates heat on demand

*: What did you learn in school today ?

2019-11-09 (The Wall)

Today, I learned about:

Berlin 1970

As you probably already have heard, today exactly 30 years has gone since the government of East Germany was pressed to permit its citizens in East Berlin to visit West Berlin, which eventually led to the extinction of the whole East Germany and its reunification in 1991 with West Germany.

The first time I visited Berlin was in May 1970, when the Wall, which divided the city into two parts, was going on its 9th year. My German language class went on a field trip for almost a week. First, we took the train to the South of Sweden, where the train boarded a ferry to Sassnitz in East Germany. After four hours on the boat, it arrived on German shores and from there it was no longer an electric locomotive pushing the train, but an old steam engine with its heavy black smoke, paving its way through the grey landscape, all the way to West Berlin. See also reference #1 below.

Unfortunately, I do not have any photos left from the trip to show, but I remember well the contrast between the two parts of Berlin. We stayed at a hotel in modern West Berlin, close to the business street Kurfürstendamm and had quite a few interesting and funny days there. On 1970-05-08 was the 25th anniversary of the end of World War II, which of course created some heavy demonstrations, and on the following day we went to Berlin’s Olympic Stadium to see the West German football team beat Ireland with 2-1.

But the strongest memory of the whole week was no doubt from the visit we paid on 1970-05-07 to East Berlin. We took the S-Bahn and after quite some waiting in the checkpoint, we were “free” to walk around in East Berlin. I remember the visit to the Pergamon museum with its majestic Pergamon altar and other impressive artefacts. But the most vivid memory comes from the film of the trip that my friend Jan Johansson and I had been commissioned to create. He was the Super-8 camera man, whereas I made the sound recordings on the brand new cassette tape recorder and interviewed people on the street about how life was in East Berlin for everyday people, a dangerous task. Only later would our teachers learn about that and reprimand us.

See also my post of 2016-05-08 .

Berlin 2007

My second visit to Berlin only occurred in October 2006, when I was there for a brief business meeting, but I also returned in June 2007, when I had a whole day to go on a guided walk through the streets of Berlin. It was extremely interesting and our guide, who was a native Berliner, had extensive answers to all of our questions. No wonder that the originally planned 4 hour walk only ended after 6 hours!

Below are some photos I took on that city walk on 2007-06-09.

The guided city walk of started at Hackescher Markt in the central part of Berlin and ended at the former Checkpoint Charlie. The explanation to the photos is in the text below. On top is photo 5. The next row, from left to right, photos 2 and 4. Middle row, from left to right, photos 6 and 7. Lower row, from left to right, photos 1, 3, and 8.

Photos taken in chronological order during the city walk:

Photo #1: Fernsehturm (TV tower) at Alexanderplatz. Since most people in East Berlin could watch TV broadcasts from the West, although it was forbidden, the East German government decided to build an enigmatic TV tower that would be seen all over both parts of Berlin. There is a rumour that the Swedish engineering firm that made the design on purpose made it so that when the sun shines on it from a certain angle, a golden cross appears on the globe. The Berliners call it the Pope’s revenge, since East Germany was so hard on religion.

Photo #2: In central Berlin there is an island named Museum Island, where many interesting museums are located. I already mentioned the Pergamon museum in 1970, but of course there are many more. This a photo taken from the steps of Altes Museum (Old museum), home to antiquities. To the left is the catholic Berliner Dom (Berlin Cathedral) and beside it, under construction, is the cultural building Volkspalast, which substituted the former GDR parliament building. The construction of Volkspalast was heavily debated both among politicians and people in general.

Photo #3: In one of the pillars of the old buildings on Museum Island can still be seen bullet holes from the fightings at the end of World War II.

Photo #4: Zeughaus (Ammunition building) is the oldest structure of the former parade avenue Unter den Linden, with parts from the beginning of the 18th century. Today it houses the German historical museum.

Photo #5: Brandenburger Tor (Brandenburg gate), located at the opposite end of Unter den Linden, is a war victory monument from the end of the 18th century. This is probably the best known landmark of Berlin still today.

Photos #6 and #7: Two photos showing what is left today of the former Wall that divided the two major parts of Berlin between 1961 and 1989. Photo # 6 is from Bernauer Strasse, taken from the former West Berlin, showing a 60 m long part of the Wall that is kept as a remembrance still today. Behind it, on the former East Berlin is now located Gedenkstätte Berliner Mauer (Berlin Wall Memorial). Photo # 7 shows one of the memorial plaques spread out all over Berlin on the exact locations of the former Wall.

Photo #8: Checkpoint C(harlie), the best known crossing points between West and East Berlin, active between 1947 and 1991. On the right side of the photo is a sign saying, in English, Russian, French, and German “You are leaving the American sector”.

More about Berlin can be found in reference #2 below.

Berlin 2019

Today, I listened to an interesting live transmission by Radio Sweden from Berlin. The reporters were standing on Bernauer Strasse, exactly on the place where I took photo #6 12 years ago. If you understand Swedish, listen to the program, see reference # 3 below.

Finally, Berlin also makes part of my series of cities around the world that has been the host of an Olympic Game. It happened in 1936, when the Summer Olympic Games were held here, with the Olympic stadium I mentioned above in my visit in 1970 being the main venue. See reference #4 below.

That’s what I learned in school !


1: Trelleborg–Sassnitz

2: Berlin

3: Murens fall 30 år. Direktsänt från Berlin!

4: 1936 Summer Olympics

*: What did you learn in school today ?

2019-10-31 (Thursday)

Today, I learned about:


During the month of October, my daughter Karina had the pleasure of presenting a project related to NLP (Natural Language Processing) at an international conference for AI (Artificial Intelligence) in Salvador, Bahia, Brazil.

While still being a Portuguese colony, during the 16th century, São Salvador da Bahia de Todos os Santos, or just Salvador for short, became the first capital of Brazil, before it later on moved to Rio de Janeiro and Brasília. Here are some nice pictures from Salvador. See also reference # 1 below.

The sun sets in Salvador, Bahia, Brazil. Photo taken from Morro do Cristo da Barra by Karina Johansson on 2019-10-18.
Six different views of Salvador. Upper row from left to right: Monument of the fallen cross in the historical center, statue raised in 1999; Karina joined the legendary author Jorge Amado, his wife Zélia Gattai and their dog Fadul on this park bench in Rio Vermelho. Lower row from left to right: The district of Pelourinho in the historical center; The Lacerda elevator, the world’s first urban elevator from 1873, connecting upper and lower parts of Salvador; A view from the Ibis hotel in Rio Vermelho; The Museum of modern art (MAM), inaugurated in 1963, with one building going back to the 16th century. All photos taken on 2019-10-17- -20.

Update 2019-11-04

Today I received more details from the conference I mentioned above. It was called STIL – XII Brazilian Symposium in Information and Human Language Technology and was held in Salvador on 2019-10-15 – – 18, bringing together both academic and industrial participants working in the areas of Linguistics, Computer Science, Psycholinguistics, Information Science, etc.

STIL also had three different collocated events, one of them being VI Student Workshop on Information and Human Language Technology (TILic). It was at TILic that Karina presented her project, Research of the use of word embeddings for calculation of similarity in translation memories, with the following abstract:

“The strategy traditionally employed by the CAT tools to match the segments of the phrase being currently translated with the segments present in the translation memory considers the intersection of the sequence of words (n-grams) present in the segments of the text being compared. However, this strategy is not capable of capturing semantic similarities beyond the trivial level. This study therefore presents a project with the aim of investigating the applicability of monolingual and bilingual word embeddings to implement the matching. The study is still in its initial phase of development. In sequence, there will be proposed and implemented a strategy for the calculation of similarity using word embeddings, which will be incorporated in a open source CAT tool. In order to evaluate the proposed strategies, the quality of matching in the baseline system (a version of a CAT system without any modification) will be compared to those of the system in which the proposed method will be implemented. At the conclusion of this project is expected to have obtained a strategy based on semantic similarity that will be an alternative to the traditional matching strategy based on n-grams. Although there are already texts covering the use of word embeddings to detect the textual similarity and cleaning of translation memories, there is no literature about any work that has investigated the objective of this project. Consequently, this study should be considered as the first initiative to an investigation within this context.”

In ref. # 2 below is the complete presentation (in Portuguese).

And here are three photos from the event. It shows Karina and her colleague João Gabriel Melo Barbirato, who presented a project named “Linguistic improvements on the text-image aligner LinkPICS”.

João Gabriel Melo Barbirato and Karina Mayumi Johansson presenting their projects at TILic19 on 2019-10-17.

That’s what I learned in school !


1: Salvador

2: Investigação do uso de word embeddings para cálculo de similaridade em memórias de tradução

*: What did you learn in school today ?

2019-09-04 (Wednesday)

Today, I learned that:

There is finally something really BIG happening in the world of serial communication between electronic devices. Last Thursday, 2019-08-29, was officialized the release of a new version of the popular USB interface, version 4, USB4 to be short, with a maximum data rate of 40 Gbit/s. See also reference #1 below.

From RS-232 to USB4

So, what is so special with this version then? Well, it seems that we now, almost 60 years after the RS-232 serial protocol was introduced, have returned to only one standard, regardless of the brand of the device.

It all started in 1960, when the American industry organisation EIA (Electronic Industries Association) introduced the RS-232 standard, initially to be used between electromechanical teletypewriters as DTEs (data terminal equipment) and modems as DCEs (data circuit-terminating/communication equipment). According to today’s standards, it was extremely slow, maximum 20 kbits/s.

RS-232 had some successors, such as RS-422 and RS-485, where both the speed and maximum cable length had been improved. For example, RS-422 is specified for a maximum bitrate of 10 Mbits/s and a maximum cable length of 1500 m.

We now jump to the 1990s, when the emerging personal computer (PC) industry found that maintaining the RS-232 communication was not feasible. There were then started two different initiatives to make communication between a PC and its peripherals much easier and faster. On January 1, 1996, was released the first version of the universal serial bus (USB). It had been developed by a consortium of companies such as Compaq, DEC, IBM, Intel, Microsoft, NEC, and Nortel. The data rate of USB 1.0 was 12 Mbits/s, which was improved to 480 Mbits/s with version 2.0 in 2001 and 5 Gbits/s through USB 3.0 in 2014, 10 Gbits/s by USB 3.1 in 2014, and 20 Gbits/s specified by USB 3.2 in 2017.

As you can see above, Apple did not participate in the USB consortium. Instead they had decided to develop their own communication interface, and attracted other companies such as Sony, Panasonic, Philips, LG, Toshiba, Hitachi, Canon, Thomson, and Texas Instruments. This group developed what came to be known as FireWire 400, aka standard IEEE 1394-1995. The data rate of this version was a maximum of 400 Mbits/s in half-duplex mode. It was followed by FireWire 800, which reached the speed of its name in 2006. However, Steve Jobs declared that FireWire was dead in 2008 when many camcorders were still using USB 2.0, instead of the faster FireWire.

Intel, which as you saw before already was a leading force in the USB consortium, now started to develop a new hardware interface together with Apple. It was dubbed Thunderbolt, and the first version appeared on MacBook Pro computers in 2011. Sony also used it in a Vaio line of notebooks in 2011. It was later followed by Thunderbolt 2 in 2013, with a maximum data rate of 20 Gbits/s.

And then, in 2016, Thunderbolt 3 was introduced, and as of now we can see that both standards are coming closer to each other, because they share the same USB-C connector. Intel decided in April 2019 to release the Thunderbolt without charging royalties from the companies who would use it, and that was the signal to finally use Thunderbolt 3 as a starting point for the specification of USB 4.

Will this mean that there is now unanimity in the electronics industry to start using only USB 4? Let us hope so, and that we will see the concrete result starting to appear in about a year or so.

There is much more to be said about this interesting topic of data communication, please see references # 2 through 7 below for details.

If you can’t beat them, join them!

A big problem in the crazy traffic in major cities around the world is of course that so many different categories of people on the move need to share the same physical space. Maybe the most troublesome is when motorbikes try to squeeze their way through in the small corridors between the cars. In 1997, when the most recent Brazilian Code for traffic was published, it permitted that they could do so, contrary to safety measures. And as a consequence, every day quite a few of those bikers are involved in severe accidents, even deaths.

If you can’t beat them, join them! In order to reduce the conflict between cars and motorcycles, in the largest avenues in São Paulo have been implemented a buffer zone, exclusive to the bikers, in front of the pedestrian crossing. That way, they can race off without messing with the cars. Photo taken at Avenida Ipiranga on 2019-08-08.

However, one of the ways to mitigate somewhat this conflict was created in 2013 in São Paulo. You can see it in the photo above, taken downtown on 2019-08-09 at Avenida Ipiranga. It shows that motorbikers and other bikers, as well, have a privileged zone in front of the cars, when they need to stop for a red light. That way, when the light turns into green, they can speed away without needing to negotiate space with the car drivers. This method is called “Frente segura”, which means ‘Safe front’. More about it can be seen in reference #8 below (in Portuguese).

That’s what I learned in school !


1: USB4 Specification merges Thunderbolt 3 and USB with transfer speeds up to 40 Gb/s

2: RS-232

3: RS-422

4: RS-485

5: USB

6: IEEE 1394

7: Thunderbolt

8: Frente segura

*: What did you learn in school today ?

2019-08-27 (Tuesday)

Today, I learned that:

There are a new number of things from Brazil that I would like to publish here on my blog, so here they come!

Gripen is in the air !

Yesterday we received the thrilling news that the first of the new Gripen fighter series on contract from FAB, the Brazilian Air Force, has made its maiden voyage.

This fabulous photo was taken on 2019-08-26 during the maiden flight of the first aircraft Gripen E of the production series, 16 minutes into the flight which started on Saab’s airfield in Linköping, Sweden.

See reference #1 below for all the details.

I would like to take this opportunity to present a tribute to all my friends at Saab and FAB, both in Sweden and Brazil, and congratulate them on what they have accomplished so far and wish them success in their continued missions.

More exciting Brazilian news will follow soon!

That’s what I learned in school !


1: First Brazilian Gripen E Completes its First Flight

*: What did you learn in school today ?