Just Keep Swimming 2021

S Association magazine of W.S.G. Abacus

Staff Says

Valente Ramírez On the Couch

Christmas Dinner Interview

Z.P.V. Piranha

Just Keep Swimming 2021

INDEX 4, 15 5 7 14 20

Columns Your Story Treasurer’s Thoughts Staff Says Pranab ‘Praat’ In memoriam Walter Kern Mathematical The Pen: Ice Madness 5

4, 11 8, 18 10, 11 15 16 17

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Fun Puzzles Interviews Reviews Abacus Needs You! On the Couch Puzzle Solutions

Editorial Dear Readers!

Nowadays I find myself sailing the rivers of memory and thoughts as that is mostly what I do during this pandemic. While looking back I remembered an event of one and a half years earlier. It was my last year of secondary school and I was talking to a girl who used to be in the same History of Art class two years prior. We were walking from chemistry class and I don’t know exactly what we were talking about, but she asked if I was afraid if during my studies I would lose my creativity, a topic she had also asked our chemistry teacher about. I answered that during my studies I would still try to make art in my spare time and that I would be more free to do so as there were no assignments attached to it. Looking back I realised how wrong I was…

when I have none of those, I know that if I started I could have done something instead of only thinking about it. It is a cycle of strong waves that I am trying to cross, but haven’t succeeded in.

But that’s enough of me blabbing, I hope your first two months of 2021 are going great and hope you have a nice read,

• 10 March Members Meet Members • 14 March Pi Day • 15 March Case SOR • 16 March Lunch Lecture Thales

Colophon

Editors: Emma Donkers Jorg Gortemaker Tim Hut Daan van Kats Lavinia Lanting Timon Veurink

• 8 March GMA

Tim

I don’t mean the loss of creativity part, but it turns out that I do need an assignment connected to it to keep the motivation to finish something. Now I think of something and am hyped to create it for a day or two, but by the time I am about to begin I have lost interest. Then instead I choose to watch a video or scroll through social media. Usually it isn’t a big deal, since when I am finished with my daily obligations there is not enough natural lighting anyway. But at the end of the days

Editorial address: W.S.G. Abacus Postbus 217, 7500 AE Enschede Phone: 053 - 489 3435 ideaal@abacus.utwente.nl www.abacus.utwente.nl

AGENDA

Guest writers: Nick Muntendam (Your Story), Daan Pluister (Treasurer’s Thoughts), Valente Ramírez (Staff Says), Joran van der Bosse (Review: SHOT), Pranab Mandal (Pranab ‘Praat‘), Anouk Beursgens (Abacus Needs You!), David van der Linden (Your Story), Diana Dalenoord (Interview: Giske Lagerweij).

Ideaal! is the magazine issue of Wiskundig Studiegenootschap Abacus and the department of Applied Mathematics.

The responsibility for the articles published in this magazine lies with the original author(s).

The period of notice of Abacus is four weeks before the end of the association year (August 1st).

That means that you must cancel your membership before July 4th. If you have forgotten to cancel your membership before that time, you will pay contribution for another college year.

Would you like to cancel your membership? Send an email to board@abacus.utwente.nl.

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Your Story Text: Nick Muntendam On the beach Terschelling is the place to be for me.

For others that may be France, Hawaii or some other warm and sunny place. For me it’s Terschelling. A couple years back my parents and I went there for Christmas after not having been there for a long time and we have been every Christmas since. It’s a time to let everything fall off you and enjoy the wind and the salty scent of the sea. There is no better feeling in my opinion than walking on the beach just out of reach of the waves with the wind in your hair and a deserted beach around you.

I always refrain from bringing study books or a laptop, because those things just don’t matter for that

week. What I did bring was my new camera. I had bought one just after the summer holidays and hadn’t had an opportunity to really go out and shoot apart from shooting in Enschede which, in all honesty, is not the most exciting place for photography. Most of my days on that island were thus spent going on walks and taking photographs. The total count of photos ended up being just under 1300. Besides walks and photography many days didn’t pass by without the occasional board or card game. Usually we would be out more than we were on Terschelling, but since the catering industry was all closed we found ourselves returning home sooner and the time left was usually filled with trying to win at Terraforming Mars. After a week of board games and walking it was time to go home again. We packed our bags and left

for the harbor to go aboard the Ms. Friesland which would take us to the mainland. And everyone who has been to one of the Wadden Islands probably knows, the holiday already starts when you are on the boat to Terschelling and isn’t over until you step into the harbor of Harlingen.

Puzzle: a sudoku knights puzzle Text: Timon Veurink As the Dutch saying goes: “Een paard in het nauw maakt rare sprongen”. Which roughly translates to: “A knight in a corner makes weird jumps”. And in this puzzle they definitely do. Next to the normal sudoku rules, the

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Knight rule now also applies. This means that a number may not appear a knights move away from that same number. So when you would look at the example, you would not be allowed to place a 7 in any of the blue squares. You might not

like extra constraints but the Dutch then like to say: “Don’t look a given cat into the mouth”. At least, it was something like that… Anyway, good luck solving this puzzle!

Treasurer’s Thoughts Text: Daan Pluister Dear reader, Just keep swimming, a sentence used a lot in the Finding Nemo movie. Because I was not scared of the shark scene, I watched this movie many times as kid. And other than teaching me that sharks don’t eat fish, and that turtles are insane, you also learn to pursue on your goal. What is important is the route you take to achieve the goal is just as important. For example, when you are trying to pass your module. What always helps for me is working together with someone. Then you both feel obligated to work because you know the other person is expecting you, and the other way around.

This week I applied this again with my housemate, we have a rule that

when the other is not out of bed at 8:10 you can knock on the others door. When you are living on your own, I would recommend inviting someone over to your place to work together or meet at a certain time on Discord. When you are going to meet on Discord you may set the rule that you can call the other person. My experience is that this is fun to do together. Because in the end, just like in Finding Nemo, it is the journey that counts. And if you just keep swimming you will find Nemo.

The Pen Text: Jorg Gortemaker Ice Madness A few weeks ago the whole of the Netherlands was put on its head when all of a sudden we had wintery weather! In several places the temperature wouldn’t rise above zero degrees for quite a few days.

I could start on about how strange it is that we even get excited for weather that shouldn’t be out of place during winter, but we can talk about that another time.

No, in this piece I would like to talk about the Dutch tradition, or Frisian if you will: The Elfstedentocht.

Every winter you can spot it again, if the weatherman even mentions 1 degree below zero: the entirety of the Netherlands breaks lose.

“Maybe we will have an Elfstedentocht this year!” or “A marathon on natural ice, it could happen!”.

Of course, these claims are usually based on thin ice, for the fact is that we would need more than 1 degree below zero.

However, this year we actually had the weather for ice thick enough to stand on, right? Well, what do we actually need for the ice to be thick enough?

Let’s start with defining “thick enough”, the organisation that organises the Elfstedentocht does not

give a minimum, we can look to the ice thickness of previous iterations of the tour. The ice has been thicker than 25 cm in 11 of the 15 times the tour has been skated, and the thinnest the ice has ever been was in 1917 when the ice was only 15 cm thick, and in 1985 when the ice thickness reached 17 cm.

Let’s be optimistic and say 15 cm would be enough. How cold does it need to be then?

We can use the following equations from thermodynamics:

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We can solve the integrals, filling in the variables and assuming the temperature of the water is at 0°C, it doesn’t have to cool anymore and only has to freeze and the temperature at the surface is the temperature of the air above. We calculate in °C.

To put this in more useful units, we can rewrite to have t in days:

Now we have found a formula for how many days of a certain average temperature we would need to reach for example 15 cm. Let’s assume we had an average temperature of at least -5 °C for a few days, we find the following: So, in optimal conditions, with water that is already near frozen and which does not take up heat

from the sun and has still water underneath, we would still need almost 10 days for ice that is thick enough.

A hard limit to reach for sure, although definitely possible.

And as I mentioned in the beginning, since people will go mad if the temperature even dips just a little below 0°C, I don’t think any calculation to show chances of an Elfstedentocht being low will stop the madness and enthusiasm anytime soon. So let’s just hope one day the reality will live up to the hype and the expectation we get every winter for that single degree below 0°C.

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Staff Says Text: Valente Ramírez What I learned in Russia I grew up in a large city in Mexico’s central plateau. Having a semi-arid climate and being halfway between the Pacific and Atlantic coasts, you can imagine there’s not a lot of water around. So unlike in other more responsible countries, children in my hometown are not required to learn to swim. I was one of the few in my class who had this privilege, which was sponsored by my mom’s fear of water. She tells the story of how one of her aunts was pulled by the ocean’s current on what was supposed to be a casual day at the beach, and disappeared without leaving a trail. This meant that a) me and my siblings all got swimming lessons, and b) whenever we went on holiday to the beach we were only allowed to go knee-deep into the ocean.

This rule, of course, stopped being observed the moment we were old enough to go on vacation with friends and far from parental supervision. In case you are imagining the cold north-Atlantic waters, you should know that a day in the beach in Mexico means lots of sun, a consistent 30o temperature, and water so warm you could stay in for as long as you want, just floating and letting the waves rock you up and down.

I never really appreciated just how nice the weather in Mexico was, until I moved to the Finger Lakes region in the USA for my PhD. The landscape was amazing and I met a lot of wonderful people, but reaching -30o in winter made me sometimes question my choices. On the other hand, having four marked seasons was quite a nice change, and the summers were long and warm (oh, if only we could have that

here!). Summers back then always meant lots of free time for me. My PhD supervisor, a famous Russian professor, would spend only half of the year in the USA, and the other half in Russia, summer included.

This brings me to the heart of my story. One of those summers I decided I would come along with him.

He used to organize these summer schools in the Russian countryside, where the Dubna river meets the Volga, just an hour away from Moscow. I was the only non-Russian participant, and they took the trouble of switching the official language to English for me. Everyone was very serious about work, and in their brief moments of leisure they would discuss politics or organize a cultural soirée. Or exercise...

One day, during a short afternoon break, I joined a group that wanted to squeeze a quick swim before the next lecture. I hadn’t swum in a while, but it was a hot day and a refreshing dip sounded like just the right thing to do. The locals suggested crossing from one shore to the other and back. They asked if I was able to swim that much. I can’t remember how wide this river was, but it didn’t look particularly imposing, and the current was rather gentle.

Of course! – I replied. I had never really swam in a river, but how different could it be from the Mexican beach? Oh boy! I might have underestimated my swimming abilities. I had a hard time keeping up with everyone else, but I made it to the other side. To my

horror, we were not stopping on the shore. In fact, the shore was covered with a lot of vegetation and we couldn’t even make it to firm ground. We immediately turned around without a break. If it had been the ocean, I could have just floated on my back for a bit to regain my strength. But this river made me feel so heavy, and it was a big effort just remaining afloat, so there was no other option but to keep on going. Halfway through the river, I was seriously struggling.

I began to think I might not be able to make it. I started to panic, which only made things worse. I didn’t want to die, but more importantly, I couldn’t die like that. Not drowning!

I couldn’t possibly do that to my poor mother. This thought gave me the clarity I needed, and with a little strength but a lot of determination, I managed to pull myself together and make it back to the shore. My heart was beating so hard I felt it was going to explode, and I was so dizzy I almost threw up over my new friends. I had to skip the lecture and go to my room in shame. But I learned two things that day: salinity in water significantly increases buoyancy; and, when you’re sinking you just have to keep on swimming.

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Interview

This time we had the honour of interviewing four of the six members of the board of Z.P.V. Piranha, the watersport association, which even in these times remains rather active.

Text: Jorg Gortemaker and Lavinia Lanting

Introduce yourselves

D: I am Denise Bouma, I am 20 years old and I am the secretary and water polo commissioner and I study at the Saxion. I am a fourthyear Forensic Investigation student.

I think that’s it.

A: I’m Aaron Hendriksen or Hendriks, and that’s really my last name. I’m 20 years old. I am an IBA freshman for the second time this year and I am the Treasurer and Rescue Commissioner.

P: I am Pieter Breel. I am 19. I am a second-year in Civil Engineering and I am the Intern and Dive Commissioner of Piranha R: My name is Rinke Hiel, I am 19 years old and I study Industrial Design. I am the vice-president and the swimming commissioner.

Which other functions are there in your board?

D: The chairman and the activities commissioner. Ilse Mulder is 20 years old and is a third-year TG and is the chairman. And then you have Romeo Dijkstra, the activities commissioner. He is 23 and doing

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a master’s degree in cyber security.

What is Piranha?

D: Piranha is actually an association for everyone who likes to deal with water, so actually water sports and that includes diving, water polo, swimming and rescue swimming.

That also makes it extra fun, because you have different branches within the association itself, so that the association is nicely divided into several cliques and yet you can all participate together at the same time. There is a place for everyone.

We currently have 251 of which 34 members have special status. So in total we have about 221 members who are active and therefore come to play sports.

P: I’m guessing we have around 60 really active members.

D: I think more. We really have a lot of committees. We have about 25 active committees. So I think we’re around 80.

A: Well, then we have roughly between 60 and 80 active members.

Describe your association in 3 words

A: cosy.

D, P, R: That’s one word. Good job Aaron!

A: Yes, but I already made a start, so if everyone now thinks of one word...

P: It is an association of people who really push and motivate each other.

R: Yes, so cosy, motivation and…?

D: Guys, aren’t we just really cool?

Every year we throw a fun pool party. I think cosy and cool fits.

P: I think maybe involved.

D: Yes, I like the word involved.

P: Well get rid of cool then. Cosy, motivated and involved.

What made you decide to become a board member of Piranha?

D: I always wanted to do a board year and I didn’t really care where it was, but what I had with Piranha was that after having been a member for a while, I thought to myself that I wanted to commit more to the association and get to know the as-

sociation better. I had already done quite a bit of committees at Piranha and this was a higher step for me.

A large part was of course also self development: gaining more experience in another area.

R: I did indeed want to do a board myself, but I found it difficult to go full-time right away, so this was ideal and you are super involved in this association.

A: I was also quite involved in my old association at home and I enjoyed being active within the association. Last year, that was also the case and my trainer eventually persuaded me to take over the board at Piranha. He is also a member of merits at Piranha. And of course the function of treasurer also fits a bit with my study.

P: I already did a committee at Piranha and I was the caterer there and the old intern, so my predecessor, showed me how to organize the event and how you could make it fun for the entire association and I wanted to help with that.

Which achievement (of your own or of the association) are you most proud of?

D: The GA minutes! The GA lasted 6.5 hours and typing all that out...

But if it is more general about the association, then the way we try to keep the association running through activities with committees.

We really try to keep engagement alive instead of thinking ‘never mind’. I think I am most proud of that.

P: I think I am most proud of the way I managed to fix the dive equipment damage without getting too many people upset.

D: I am also proud of how much I have learned about the association. Whether it’s useful is secondary, but you really find yourself learning a lot.

A: I think communication to our dive

branch has improved a lot compared to previous years.

R: That we can still organize competitions in between, including the NSZK (National Student Swimming Championships). There will be one in Enschede in June (there are 4 in a year) and that is quite a task to organize, so I think I can be proud of it soon.

How has the current situation impacted your work as a board member?

D: Well, we have to prepare documents for the General Assembly and that can be quite difficult online due to lost internet connections and people who want to bring in discussion points but that does not work because only one person can speak, and that has hindered us very much. . The contact among each other was also difficult because we only got to know each other well after six months. That’s a shame.

R: Also just getting to know faces by going to a swimming training, for example, is not happening anymore, so you end up knowing fewer members than you hoped.

D: There are also members who do not know who you are as a board member. Recognition towards members is simply very difficult.

A: One of my attention points was to have good contact with the members so that I could also be a point of contact from a financial point of view and that is hardly possible to achieve.

P: The social contact has disappeared and the social activities such as bar shifts, kiosk days and work actions have also disappeared.

In what ways is Piranha still active during these times?

D: We now mainly have activities online, so that way you still have

contact with each other, but we also don’t know exactly what is expected of us. We are now looking at replacing workouts, because you cannot swim. However, it is now mainly fixed groups that are present at activities. Nobody wants to participate in an online activity where you don’t know anyone. But we do have a standard 40 people or something who always responds positively and comes along.

R: I must admit that sometimes it is also the case that you organize an activity and then 15 minutes before that you don’t feel like sitting behind the computer at all, but then you still do because you get to speak to people and that is very nice in these times.

D: There are also committees now that are super active and have become very creative in devising and organizing activities. I think we currently have an average of just over 3 activities per month.

Why should people join Piranha?

D: You stay fit by exercising, but you also party a lot so that you still get the beer belly.

P: You also get to know really good friends.

D: It doesn’t matter who you are either. At Piranha you are always accepted for the person you show within the association. There is always a place for everyone and you are never treated badly. You are not judged for what can be seen on the outside. We are a very open and friendly association where you can also play sports by chance.

A: I think it is a good summary.

What events are you most looking forward to?

A: Our Constitution Drinks.

P: The pool party.

D: The water polo tournaments and the NSZK, the work actions.

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R: The big events.

What would you say to the people of Abacus to convince them to join?

R: It’s mostly personal: you just have to be interested in water sports in the end. But as we said before, Piranha is very nice and you can fill in what you want to do and how much you want to bet, so for example swim once a week or

do water polo twice then swim and add a committee, you can make it as crazy as you want.

D: Besides sports, Piranha also offers a great deal of self-development, so that you can get much more out of your student life.

Any closing words?

D: Nice that you do this! I think it’s a pretty nice addition to your magazine.

Review: SHOT Text: Joran van der Bosse Back in the 19th century the English mathematician James Joseph Sylvester wondered, “May not music be described as mathematics of the sense, mathematics as music of the reason?” It should not come as a surprise that lots of mathematicians make music in their spare time. Personally I started playing the clarinet when I was 9 years old. At the age of 11 I joined a wind orchestra for the first time. I remained a member of that orchestra until I moved to Enschede, so it was an easy decision to join a local wind orchestra here.

Studenten Harmonie Orkest Twente (SHOT) is the wind orchestra for students in Enschede. The association counts approximately 65 members, among whom quite a

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number of mathematicians. When no Covid measures are in place, we rehearse every Thursday for 2.5 hours.

Moreover, twice or thrice a year we move to some small town in Twente for a rehearsal weekend. Several times a year we give concerts, which are mostly in the Vrijhof but also elsewhere.

In the attached picture SHOT performed in the first division of a concours in Zutphen, a contest between orchestras. Once every two years SHOT even organizes a concert trip abroad, a figurative high note that all SHOT members look forward to. If there hadn’t been a pandemic SHOT would have been able to perform in the famous Golden Hall in Vienna, the same place where the Wiener Philharmoniker performs its traditional New Year’s Concert. So the rehearsing efforts pay off.

During rehearsals we mainly focus on preparing music pieces, but SHOT members socialize too. After rehearsals usually some people stay to have a drink. Besides that, during rehearsal weekends

we all stay at the same location during the whole weekend. This provides room to talk to a lot of different people during the rehearsal breaks and to have some long lasting parties into the night. This allows us to really get to know each other well. A rehearsal weekend has such a typical atmosphere of both hard work and lots of fun that many consider it the ultimate SHOT experience.

On 1 April 2021 SHOT celebrates its 30th anniversary. The lustrum committee has some great activities in store. Among those is the traditional lustrum concert of SHOT and SOLO (SHOT Oud Leden Orkest, an orchestra consisting of old members). Due to corona this has been postponed to 2022. By the time it is certain when the concert will take place more details of this concert will be made public. But hereby I already would like to invite everybody to come, either as member of the orchestra or as part of the audience!

Review Text: Lavinia Lanting ATTENTION: the following may contain spoilers for WandaVision and the MCU (Marvel Cinematic Universe).

If you are interested in watching it, I suggest getting up to date before reading this. If not, go ahead and, who knows, you might consider watching it afterwards.

If you’re a (huge) Marvel nerd like myself and have watched (almost) all of their movies and even if you are casually interested in what Marvel produces, you might have heard of their most recent series: WandaVision. Actually, let’s be honest, you might have heard of it even if you detest Marvel.

Even before watching it myself, I had already been hearing about it for months: and how could have I not? Disney+ was all about it, trying to get even more people to subscribe with this new awaited project and it is no secret that about 25 million dollars have been thrown as budget into each episode (yes, 25 million per episode of about 24 minutes excluding the credits).

WandaVision was a major hit even before it was released. The trailer was vague and endearing (as to be expected for such a series), every single publicity for subscribing to Disney+ had doubled in length to be able to include a decent amount of scenes as preview and loads of people on the internet were speculating about what this series might

be all about (especially given the quite amazing budget).

The series, as the title might suggest, follows the adventures of newly married Avengers Wanda and Vision, who just moved to the sunny village of Westview and now live their lives in a literal sitcom, with the (for me currently) latest episode being a clear reference to ‘The Office‘. Each time we get to peek into Wanda’s and Vision’s life in Westview, we also change setting as different sitcoms, one per decade, is referenced to and ‘replicated’. Of course, this is not all we get to see, as more and more interferences start affecting the broadcast and we are shown what is happening outside of Westview and how this, as well as previous milestones in the MCU, all are intertwined and how we ended up in the current situation and how it is possible that Westview seems to be nonexistent and that, a now technically dead Vision, is alive and well and even has kids with Wanda during the series. Has Wanda created an entire tiny universe to be able to live out her life with Vision and has she captured an entire town as side effect of that or is somebody else moving the strings from the dark background?

This is a series filled with cliffhangers and that slowly but constantly reveals more and more to the viewer to give a more and more colourful picture of what is going on, just as the sitcom Wanda and Vision live in takes colour.

While I personally do enjoy the se-

ries thus far quite a bit, I’m not entirely sure the enormous hype preceding it did the series any good.

WandaVision is a series with quite the slow pace. A very clear example of this are the first three episodes: while you can definitely see that something is not right in Westview and that something from outside is trying to communicate with Wanda (also, Wanda does rewind and rewrite the sitcom when something she doesn’t like happens) those are quite minor moments. Most of the 24 minutes are spent showing how happy Wanda and Vision are together and what their life looks like. It is only starting episode 4 that we really get a glimps of outside of the sitcom and even then the development of the series is rather slow: not much happens during one single episode and the truth behind everything is being unveiled rather slowly.

The overhyping of the series and the gigantic budget caused most people to expect a series full of action or a fastpaced story, but that’s not what WandaVision is like at all: they even have time to include publicities in the middle of each episode (meaningful, but publicities nonetheless).

Overall, I think that WandaVision is a series for people who want to see a new side of Marvel: one where action is not all and where connections between and development of the characters is far more important and meaningful. I can definitely recommend it, as I, for one, enjoy the slow climb to the peak.

Puzzle Text: Lavinia Lanting A while ago the Ab-Actie had the pleasure of organising an online Escape Room in cooperation with the www.com. While this escape room wasn’t nearly as fancy as the one the committees of Abacus received as gift for Sinterklaas, we thought

readers of the Ideaal! might enjoy a different challenge than usual to work on in their own time. This escape room takes place across different webpages with URL of the form: abacus.utwente.nl/go/ SOMETHING

A hint to entering this escape room, may be found on the page of the committees who most care for it.

P.S: we suggest you take a good look at the first URL you will find.

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Just Abacus things...

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Pranab ‘Praat’ Text: Pranab Mandal How do you solve a problem like Corona?

This seems to have become our perpetual question day in and day out, starting even before sunrise and continuing after the sunset. So much for our hope at the beginning of the academic year that the good times are just around the corner!

I must, however, continue to applaud the fighting spirit among the teachers and students alike.

Many things we take for granted, like the human touch, until we cannot have it any more.

We, the teachers, get energy by seeing the faces of the students.

Not only when they light up with the appreciation of understanding, but also when there is a confused look.

The latter can invigorate the teacher with renewed enthusiasm to explain differently and drive the point home. Now that this weapon has been taken away from us, we have to be innovative. Reorganise the activities to extract the maximum “contact” from the online sessions.

Keep the parts where interaction is not required to off-line, such as “knowledge gathering” via videos, and incite maximum interaction during the online meetings.

Students, on the other hand, are deprived of one of the most effective and enjoyable ways to learn -studying in a group; learning from each other.

If I look back at my student time, was it only study together? Definitely not. Otherwise, I would not have such a pleasant memory of that period. We were sharing our lives together!

Every group-study inevitably involved somebody sharing something unrelated to the study, which will trigger some more leg-pulling.

Unknowingly, these forced us to take a break, only to concentrate

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back to the study again, making the whole study-process to be effective. I feel really sorry that the starting students are missing out on this now.

Nevertheless, once again, my hats off to the students: there is no dearth of good will (in) hunting for that perfect solution.

The current situation has engulfed us so profoundly, even if we have something to talk about other than the pandemic, the conversation veers back to the latter in a matter of moments. How I would have loved to share with you my trip to India last December travelling around in the pleasant warm weather! Or about that conference, where the host opened it with “welcome to the chilly weather in Kolkata” when the outside temperature is 18-degree centigrade! If you think about it, it is not that surprising, especially if you compare with the summer temperatures of 35+. Besides, the houses are built there to protect from the heat, often having windows designed to let air pass through. As a result, the temperature inside is not much different from the outside winter-temperature.

Unfortunately, this is only a fantasy; it did not really happen; at least, not during the last December. Instead, we were here in The Netherlands, in a stricter lockdown than until that time.

In retrospect, I was lucky enough to have my family around, which cannot be said for some of you, who had to stay home alone due to the travel restrictions.

At this very moment (beginning of February), we are even having evening curfew. So, the answer to guess who is coming to dinner is a trivial one.

It is a pity that we all have to go through this hard time, but staying optimistic, I am sure we will come out stronger at the end.

Coming back to the question I started with, let’s hope that roll-out of

the vaccinations programme will bring the sound of music to our ears. But until that time, the only thing we can do is stay afloat and just keep swimming.

Abacus Needs You! Text: Anouk Beursgens

Sport Day Committee

The sports day committee is in charge of organising the annual sports day of Abacus. The sports day consists of a round of several fun sports games, one including an epic inflatable object, and a beach tournament. If you have no commit-

tee experience, no worries, it is an easy committee to start your active members career with :) So do you like organsing an amazing afternoon and/or fatiguing your fellow students?

Make sure to show your interest by emailing to education@abacus.utwente.nl!

neers did most of the designing in solid works. We were programming on a micro python module. Due to the corona restrictions we were not able to all meet up. This led to me writing a piece of code without being able to test it on the module.

The moment when I uploaded that code, and then the robot played the song on its first try was amazing.

exercises together really made a big difference in this Corona restricted module.

Your Story Text: David van der Linden Going into my minor I was hoping to get to play with some robots and do some tinkering.

The project starts off by guiding you through some basic design principles.

After that, you come up with the purpose of your robot. We chose to make a robot that enables people with a muscle dysfunction to play the xylophone. Then you make a few designs on “paper”, and after that a solid works design.

My project group consisted of three mechanical engineering students, one electrical engineer and me. Initially we wanted to follow the advice of lecturers, and not do the things you are good at, so that you learn the most. But due to time restrictions we came back on that, and I ended up focusing on programming while the mechanical engi-

The main things I’ll take away from this project are knowing how to do objects oriented programming, some more knowledge of programming in general, my first experience with solid works, and my first experience with a small programmable computer. Like the micro python module we used this project.

There were three courses in this module. The most interesting one I found to be robot kinematics (RKI).

In this course you learn to use concepts like wrench and twist and in general how to deal with multiple coordinate frames.

Most importantly, I found this a fun module that shows you some interdisciplinary collaboration.

There is one vital thing that led to me enjoying this module a lot. A study group. A small (online) group of people who just chat with each other and make

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On the Couch with...the Christmas Dinner Committee Text: Timon Veurink

1. Give a little introduction about yourself, like, who are you, what are your hobbies, what is your favourite toast recipe AM: My name is Amalie and I am 19 years old. I love everything that has to do with music, singing, playing the piano and writing music. I also love to play basketball, but due to an injury I haven’t played it for a couple of years now. I do not have a toaster so I tried pan toasts, which might be actually better. I like my toast with cheese, chicken and pineapple. Or with mozzarella, pesto and tomatoes.

AL: Hey, my name is Alex, I am 20 years old and I live in the great city of Oldenzaal. I enjoy cooking, gaming and sports (kung-fu & karate).

I currently am attempting to learn guitar but that is not going very well. I also enjoy being an active member at Abacus in various committees. The ultimate toast strategy is making toast with ham and cheese in the following order: ham, then cheese and then ham again.

W: My name is Wessel, my hobbies are korfball and chess and my favourite toast recipe is when you toast 2 slices of white bread with peanut butter.

The rest of the committee was confused, though accepting of Wessel’s life choices, some even considering to try it themselves.

D: Hi, I’m Daan. I am 19 years old, I am now in Enschede and I like

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playing piano. Sometimes I also like playing my piano at home even though it hasn’t been tuned in like 15 years, but oh well. And I like listening to music.

2. How long have you sat on your chair?

D: 10 minutes.

AM: At this moment…21 minutes.

W: I just had to tidy up some things, so that would be 10-15 minutes ago.

AL: Like...a quarter of an hour. Something like that.

3. What is your favorite article in the Ideaal!?

A soft “oh no” was heard in the background.

AM: It was called “the pen” right? I really like that one.

D: The book reviews? Haha, I really have no idea.

4. What was the highlight of your day?

W: Mine will have to be Python I guess, because it’s what I’ve been doing all day.

AL: For me it would absolutely be this cookie, because I can’t deny how delicious it is.

D: I’ve been to the baker, which was pretty fun.

AL: I just realised, a moment ago I tried origami for the first time.

AM: Yesterday I bought some amazing cheese and this morning I ate a delicious piece from it.

5. What will be the highlight of your day?

AM: This evening my mother will have an online bingo show from her work, and everyone’s family is joining, so I will go home and do that then.

W: I am going to work tonight.

AM: Where is it that you work anyways?

W: Domino’s, I deliver pizza.

Timon: Well, Alex, what will be the highlight of your day?

AL: Funny you should ask. I was just thinking about ordering some pizza.

Everybody laughs.

AL: And afterwards I will take a bunch of treats to the couch and start binging Avatar.

D: I’m going home and maybe I’ll have some nice dinner.

6. What would your perfect lunch be?

AL: Well, I just really like ham cheese toasts, but a hotdog also sounds really good.

W: Yeah, something like that, or a hamburger.

AM: I think a really nice smoothie, combined with a salmon salad.

D: I have to think back to high school when we always ate meatball sandwiches.

7. What is your favorite math theorem?

AM: I immediately think back to all the Analysis theorems we had to cram…

So then probably the Mean Value

theorem.

W: I can’t think if something right this instant, but I would say maybe the Master’s theorem that we have just discussed during Applied Discrete Mathematics.

AL: I then also like the fundamental theorem of Calculus. At some point you learn this after having used it for 5 years.

AL: I don’t know if it counts, but just the concept of Fourier series also fascinates me. It’s just nuts to me that this is even possible.

8. Are you a cat or a dog person?

AM: I don’t really like pets that shed hair and stuff, but, if I had to choose, it would be a dog.

W: I also don’t really like pets.

AM: Yay, I’m not the only one.

AL: At the moment a cat person, because I have two cats myself, but later a dog one probably.

D: Yeah, the same I think.

This is the moment everything changed, because Alex had to go, so we all gathered for an Alex question speedround!

Cayley or Hamilton?

I don’t know…Hamilton

What are you eating tonight?

Pizza!

What are you going to do next?

Study most likely.

start traveling toward my parents, hoping that I can even get back.

W: The same as I was doing before: Python.

When the calm and order had returned, we continued with the regular ‘On The Couch’ interview.

12. What Abacus activities do you most enjoy right now?

AM: At this moment?

D: A bit difficult to say at this moment…

AM: I think the lunch lectures are pretty chill.

W: I really like the casual Fridays.

9. Cayley or Hamilton?

AM: Both, because when I hear Cayley-Hamilton I think of Hans Zwart and I think he’s a really good teacher.

W: Then I will go for Cayley, because Hamilton is the name of someone who is just a little too good at Formula 1.

D: I’m also for Cayley and for the exact same reason.

10. What are you eating tonight?

D, W: I have no idea.

AM: I think...pasta! But like the ravioli or tortellini thingies. With spinach and pesto.

13. Do you have a message from the Christmas Diner committee that you want to share with all the readers of the Ideaal!?

After some discussion, this beautiful Christmas thought arose that concludes this interview.

“Every day is a good day to celebrate Christmas, even when it’s in June”.

11. What are you going to do next?

AM: Groceries, before the snowstorm hits and we all get snowed in.

D: I’m gonna gather my stuff to

Puzzle Solution: Christmas Word Puzzle Text: Daan van Kats Descriptions: Vertical: Some sequence interviewed in every Ideaal!

Horizontal: 1: Discord function to be paid at the end of each month 2: λ-distribution of a small family member

3: Counting till the 24th of December with a lot of positive energy 4: Proof technique for linguistic people 5: A frightening Christmas singer 6: Enemies on the 31st of December

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Interview: Giske Lagerweij Text: Diana Dalenoord Mathematical calculations save lives After obtaining her Bachelor’s degree in Applied Mathematics, Giske Lagerweij decided to take up the Master’s programme in Applied Mathematics to become an expert in solving societal challenges from technology to healthcare. Since two years, she is a scientific researcher at the National Institute for Public Health and the Environment (RIVM) and is involved in conducting research and making calculations of the burden of infectious diseases.

What ultimately made you decide to pursue a Master’s degree in Applied Mathematics at UT? “I chose to do a Master’s programme in Applied Mathematics mainly because the lecturers and professors saw merit in my desire to do something medical. I didn’t want to make timetables for a hospital, I wanted to go into a hospital and do something cool with my maths.

I was allowed to take electives at BMT and TG, and I wrote to hospitals, the Roessingh and companies for an internship assignment.”

As you mentioned, you wrote to various medical institutions for an internship assignment. You eventually ended up at the Medisch Spectrum Twente in Enschede.

What did your internship assignment entail?

“I did my internship at the Department of Nuclear Medicine, and it was mainly about PET scans (positron emission tomography). A patient is injected with a radioactive substance, this substance decays and the degree of decay is measured. The degree of decay is converted into images, and with these images, doctors can determine the location and size of (abnormal) tissue. In this way, patients can be treated better, because the location of the tumour, for example, is properly determined and the sur-

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rounding tissue is not irradiated.

I focused on tumour tissue. However, the conversion of decay into images is not always very reliable; there is a lot of noise on the line. My assignment was to find out whether you can determine which pixel in an image is “noise” and which pixel is (possibly) a tumour.

I think the broad knowledge you gain from studying applied mathematics helped me enormously. The assignment was applied, but because of the broad insight you gain during the study, you start looking in a direction for the solution (and sometimes this direction is wrong and you have to change your plans after three months). As a mathematician you have a wide range of knowledge, usually not in detail, but approximately, after which you can of course go into depth at a later stage by specialising.”

Was this also the moment when you knew you wanted to continue in healthcare after graduation?

“Yes indeed! I have been interested in technical and medical matters since secondary school. Before I went to study at UT, I was in doubt between mathematics and medicine (technical). Medicine was soon dropped, then I had to choose between Applied Mathematics or Technical Medicine. There is mathematics everywhere, so I knew that somewhere along the way I would be able to fulfil my wish to study a programme that offered the combination of mathematics and something medical. In the end, I decided

for the bachelor’s and later the master’s programme in Applied Mathematics.”

After you graduated, you were not done learning and chose to do a PhD in the research field of epidemiology in Utrecht.

How did you get the idea to do PhD research?

“I ended up in Utrecht via a small diversion - I used to work for a software company in Deventer.

Although I always said that I absolutely did not want to do a PhD, I changed my mind after two years of working in the business world. I found out that a PhD position would not be such a bad plan. I wanted more depth and I missed the link with mathematical applications in the medical field. Nothing is as changeable as the human being, right?

The choice for Utrecht was a coincidence, they offered a nice PhD assignment where they were looking for someone with a maths/economics background. I was on the edge of epidemiology, the really technical maths side.

During my PhD, I also completed the full master’s programme in Epidemiology. This master’s opens doors for researchers without a medical background to still be able to take on medical issues.

With my mathematical background, during my PhD I focused on the (economic) evaluation of preventive interventions for cardiovascular diseases. This meant analysing prediction models, writ-

ing (time-consuming) scripts, converting problems into applied solutions, thinking logically about ‘how should I approach this problem?’

And what knowledge can I use from my master’s degree to tackle this problem?”

You have now been working at the National Institute for Public Health and the Environment (RIVM) for almost two years. What is your work about as a scientific researcher?

“My work involves calculating the burden of infectious diseases. This includes all kinds of infectious diseases such as HIV, influenza (flu), but also food-related infectious diseases such as salmonella, norovirus (stomach flu) and toxoplasmosis. In total, we calculate the burden of disease for some 41 infectious diseases. The burden of disease is a term used to express the number of human lives lost, through disability and/or premature death, for a particular (infectious) disease.

In addition, I also work on mathematical models for other purposes, such as predicting infections or calculating the costs and benefits of interventions to prevent/reduce infectious diseases.

And in case you are wondering, am I also working on COVID-19? Yes, I also work on COVID-19 related issues, both calculating the burden of COVID-19 and making mathematical models.

On the RIVM website, I learned that ‘living as healthily as possible in a safe and healthy living environ-

ment’ is the goal of the RIVM. That is, of course, a wonderful aim and we all benefit from it in this society. The RIVM’s scientific research has three content areas: Infectious Diseases & Vaccinology, Public Health & Care and Environment & Safety.

You are positioned within the domain of Infectious Diseases & Vaccinology. During your Master’s degree in Applied Mathematics, you had heard about the RIVM and it seemed like an interesting employer.”

Why do you think the RIVM is the right employer for you and especially within the domain of infectious diseases & vaccinology?

“I think all domains have a lot to do with mathematics, there is a lot of calculation within the domains. I happen to work under this domain, but there are at least as many mathematical models or mathematics is applied within the other domains.

After all, mathematics is in everything, whether it is modelling the spread of (infectious) diseases, calculating costs and benefits or of course a lot of statistics when analysing patient research, on which many epidemiologists work.

Naturally, I use the knowledge from my mathematical past in the performance of my work. Coincidentally, I recently applied basic calculus, because I was looking for a term in such a way that my (probability distribution) function actually became a probability distribution function.

All integral and differentiation rules were used again. There are no specific subjects that I apply or use extensively in my work at the moment, it is mainly the combination of subjects and the experience of bringing together the knowledge from various subjects. It is really the total package that I use, the analytical ability to see connections, ask good questions and think logically.

Combining linear algebra, scientific computing, statistics and probability, calculus and programming into one.”

Can you give an example of a project you have worked on?

“Every year, a number of reports are published on the occurrence of infectious diseases in the Netherlands. These reports present the burden of disease. I am involved in conducting research, which can sometimes serve as the basis for advice. My contribution is mainly in picking up tasks quickly, and because as a mathematician you develop an overview that enables you to quickly see what you have to do, what happens in some cases, how things fit together and in which direction you can find the solution.”

You are not currently working on projects within the RIVM together with the UT. Perhaps this will happen in the future.

When you think back to UT, what do you immediately think of?

“I think of the (special) lectures of certain teachers, the solidarity between students and sometimes also teachers, the friendly atmosphere of the UT, the nice study association Abacus, the doors of teachers that were open, etc.”

Would you recommend study seekers to pick up a master’s degree in Applied Mathematics?

“YES! I said before that mathematics can be used everywhere! You are an indispensable link in society, you can use and apply your knowledge everywhere. It is difficult to explain to third parties what an (applied) mathematician can do exactly. Besides enthusiasm, you need (a lot of) perseverance, but in the end it’s true: nobody can do with- out mathematics and therefore not without mathematicians ei- ther! In your work environment it won’t happen often that you collaborate with several mathematicians who have studied the same as you. You are often an exception within the group, but that also makes it very special. You can easily adapt and empathise with others making you a valuable colleague within the group.”

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In memoriam Walter Kern was unable to make progress in his research was happy to pay Walter a visit.

He knew a way out immediately or was so intrigued that he managed to find a solution within a few days.

Walter was also an excellent teacher, a great friend of classical lectures on the blackboard, and he has trained many generations of students with enormous patience.

Several of Walter’s former students are now active as professors and share his good taste for the beauty of mathematics, and the most elegant argument. Walter was also active for many years on the faculty council of the EEMCS faculty.

With pain in our heart we share the news that Dr. Walter Kern has passed away on January 29, 2021. We share the following message of the faculty: The news that our esteemed colleague Dr. W. (Walter) Kern passed away on January 29, 2021, has touched us deeply.

Walter, born in 1957 in Nürnberg, graduated in Erlangen and received his PhD in 1985 from the Universität zu Köln, was a Mathematician with heart and soul. As associate professor in the Discrete Mathematics and Mathematical Programming group, he worked for the UT since December 1988, more than 32 years.

Walter had impressive qualities as a researcher in discrete mathematics, optimization, game theory and operations research. His mathematical knowledge was broad and deep. He was known within the group as the `lexicon’ - anyone who

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In the summer of 2020, he was diagnosed with cancer -after some complaints. In his unique way, he still made jokes about it at the time.

But what followed was an almost unbelievably rapid deterioration of his situation, with more and more surprises. Unfortunately in a negative sense. Even recently, he still had hope, but interspersed with the idea of the inevitable.

We are going to miss very much his advice in mathematical questions, but especially his calm demeanor, his modesty, his helpfulness, his fine humor, and his counterbalance to the delusion of the day.

Our feelings of sympathy go out to his partner Angela and two sons Anton and Julius, further family and loved ones.

A message on behalf of the Executive Board and the staff and students of the University of Twente, Prof. Joost Kok, Dean Faculty EEMCS

Prof. Stephan van Gils, department chair of Applied Mathematics Prof.dr. Marc Uetz, chair Discrete Mathematics and Mathematical Programming The board, Daan, Luuk, Daan, Jorn, Anouk and Clara