On the Move 2022

S Association magazine of W.S.G. Abacus

Interview

Lotte Weedage A Day With...

The Candidate Board Dieuwertje Alblas

Do you have a minute to talk about INRs?

On the Move 2022

INDEX 4 5 9 35

Columns General Adjunct's Thoughts About MaST The Pen Your Story Mathematical Olympics, but for Mathematics!? 9 Data Analysis in Sports 10 Do you have a minute to talk about INRs? 24

6 7 8 11 12 17 19 22, 28 27 30 33 34

2

Fun Review: Fanaat On the Couch Puzzle Solution Meme Page A Day With...

WALVIS Chain Interview Interviews Vacation Map Summer Recipes Summer Events Agenda (Beer) Yoga

Editorial Dear reader, The weather outside is steadily improving despite the Netherlands' characteristic clouds being present as I write this. The increased temperature draws people out and the campus is now filled with people enjoying the heat. Some association has sponsored free van der Poel ice cream and there is a line stretching across the O&O square. In Educafé, students are furiously studying for their last few exams, including myself.

contains fellow students' travel plans, an interview with Lotte Weedage, a closing interview with the 54th board and an interview with the candidate 55th board.

I hope you will enjoy this year's final edition and I wish you a great summer!

Eva

AGENDA • 30 June 20:00 Mathematical Lounge Old School • 1 July 16:00 FriAD • 4 July 12:45 Smarter by the Second Episode 15

As a first-year, I’m shocked to realize how much I’ve grown as a person and a mathematician this year. I remember the first few days of classes, still learning everyone's names and writing my first proof, an experience all mathematics students can relate to. As this year comes to an end, I wish everyone luck on their final exams and projects as well as congratulations on completing another difficult year.

• 5 July 12:45 Master Evaluation Lunch • 6 July 12:45 Smarter by the Second Episode 16

I am also looking forward to the adventures I have planned for this summer. Travelling to the beaches of France and all over America in order to see my family, which I haven’t seen since August of last year. I’m sure every student reading this is also looking forward to their own plans.

• 6 July 16:00 The Big Swim

As travel entertainment, this particular edition of the Ideaal!

Colophon Editorial address: W.S.G. Abacus Postbus 217, 7500 AE Enschede Phone: 053 - 489 3435 ideaal@abacus.utwente.nl www.abacus.utwente.nl Editors: Jorg Gortemaker Tim Hut Daan van Kats Eva van Laar Lavinia Lanting

Guest writers: Ruben Hoeksma (General Adjunct's Thoughts), Hans Zwart (About MaST), Emile van der Meer (Review: Fanaat), Jorn de Jong (Puzzle Solution: Frog Grid), Bram Kanger (The Pen), Herkus Jacina (Olympics, but for Mathematics!?), Marjolein Bolten (Data Analysis in Sports), WHALE (WHALE page), Diana Dalenoord (Interview: Lotte Weedage), Dieuwertje Alblas (Do you have a minute to talk about INRs?), Timon Veurink (Your Story).

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.

3

General Adjunct's Thoughts Text: Ruben Hoeksma minutes and 40 seconds to ride the 21.23 kilometres and climb the 1564 meters to the top. The subsequent descent took me 14 minutes and 21 seconds. I know that at least one of my fellow board members would do the climb much faster, so perhaps we will see that story some time in Ideaal! as well.

When I was asked to write this text, I already knew that Tour du ALS was coming up, so I had decided that I would write about it. What I did not decide was what I would write exactly. I want to conclude with the following: stay on the move because you can and whenever possible make sure to make it as easy as possible to be on the move for those who are less able.

Ruben Hoeksma General Adjunct 54th board of W.S.G. Abacus

In the final edition of the Ideaal! of this academic year, as General Adjunct of W.S.G. Abacus, I have the pleasure of writing something for you. In this piece, I will deviate from the usual (mostly) mathematical texts in the Ideaal! and, instead, write something personal that has everything to do with this Ideaal!'s theme "On the move".

During the last five months, I have been on the move a lot on my bike.

The purpose was training, training to climb Mont Ventoux, a French alp with a summit at 1930 m altitude.

In fact, I was training to climb the mountain trice, in the context of

4

Tour du ALS, a charity event to raise money for ALS research. My father was diagnosed with ALS last year and I am now seeing from up close what it means to lose your ability to move. He is just one of the people that I have met for who not being able to move (because of decease) has a big impact. It has made me more aware of what it means to be able to move whenever and however you want.

To still include some numbers in this text, I will add this: On the last day that I spend near Mont Ventoux this year, I climbed the mountain a single time. It took me 1 hour 47

About MaST Text: Hans Zwart

It is my pleasure to write about the topics which are of interest to the staff within MaST and thus may lead to possible final projects and/ or practical traineeships.

MaST (short for Mathematical System Theory) is the new name of the chair formerly known as HS (Hybrid Systems). As is indicated by the name, we work on the area of systems theory, which is closely related to control theory/technology. In Introduction to Systems Theory (AM-B) you may have seen important topics within this field, e.g., stabilizability and controllability. However, there are many more questions which we try to answer.

Since we recently got some new staff, I start by listing the researchers within MaST and shortly indicate where they work on. I do this in alphabetic order, and so I will be last.

• Silke Glas. She is an expert on model reduction, which uses mathematics to obtain satisfactory solutions for prohibitively hard problems. Applications range from finance to physics.

In her research she combines different techniques ranging from machine learning to numerical analysis.

• Pranab Mandal. His line of expertise is to derive useful information about stochastic sig-

nals from noisy observations.

He works together with Thales (Hengelo) on techniques to process radar measurements and, e.g., to classify an object whether it is a drone or a bird, etc.

• Gjerrit Meinsma. At the moment he is finishing a book on optimal control, i.e., how can we control a system with minimal cost (such as energy). However, his expertise includes also robust control. In robust control the aim is to design a controller which does not work only for your model, but also if modelling errors were made. For instance, in the parameters.

• Jan Willem Polderman. Presently he is director of education of IDE, but also involved in the research and teaching of MaST. He is one of the lecturers for the MasterMath course ''Systems and Control''. His research interest is stability of switching systems and using system theoretic techniques in coding theory.

• Frederic Schuller. His background is in mathematics and physics, and thus he is a very natural choice for AM/AP double degree students. His research spans from the mathematical foundations of general relativity and quantum mechanics to dif-

ferential geometric methods in advanced robotics (such as the robotic bird built and studied by the RaM group).

• Felix Schwenninger. In the master you will meet Felix when you take the course Applied Functional Analysis. Within MaST his research focusses on the analytical side of systems theory. More generally, Felix is interested in (functional) analysis and operator theory, e.g., in the context of partial differential equations.

• Anton Stoorvogel. As you will know he is the director of education for AM. However, more importantly, he is the person to contact when you would like to do your masters within MaST. His present research is on synchronization of multi-agent systems, which has its application in electricity networks.

• Hans Zwart. My primary interest lies in systems described by partial differential equations (PDEs). Within this class I have many subprojects. For instance, with Jaap van der Vegt I work on numerical techniques for solving PDEs, but via my contacts at the Eindhoven University of Technology, I design control algorithms for them.

As you can see above, the list of research topics within the group is quite broad. It becomes even broader when you take our partners into account. Next to me, other group members work together with staff from the third and fourth floor, or with researchers within EEMCS, TNW, etc.

I hope the above have given you an idea of the richness of topics studied by MaST. Of course, my door (and mailbox) is always open for those who would like to know more.

5

Review: Fanaat Text: Emile van der Veer I really enjoy playing some games, be it board games, computer games or something else.

That’s why I joined the board game association on the UT: Fanaat. Fanaat has its association room in the Drakenkelder (Dutch for Dragon Dungeon), in the Bastille. This room is shared with Bellettrie, another association I am also a member of.

On Tuesdays and Thursdays, Fanaat organizes game evenings, during these evenings you can drop by and play some board or card games and just have a lot of fun. The thing I do most in Fanaat is Dungeons and Dragons or D&D for short. This is a tabletop role-playing game which I find really enjoyable. I have been playing this game since high school and wanted to continue playing when I came to the university. Fanaat organizes so-called Dungeon meetups, where you can find other people that play the game and need more players or a Game Master. So since the start of this year, I have been playing D&D every week with this group of very nice people.

Besides that, I sometimes join a game evening, but I am not really an active member.

Bellettrie is first and foremost a student library, mostly with Science Fiction and Fantasy books. They

6

also have a collection of manga and comic books. Bellettrie organizes anime evenings on Fridays, in which you sit together and watch an anime, quite often a film, which can be a lot of fun. They also organize writing evenings on Wednesday and Dance Dance Revolution evenings on Monday, but I have not joined those yet. Bellettrie also organizes Konnichiwa, which are mini anime conventions. They seem like a lot of fun, but unfortunately they somehow manage to plan most of these Konnichiwa on times which I am unable to join, so I have yet to attend a single one.

As I said earlier, what I do most in this association is D&D. Fanaat organizes Dungeon meetups and they give you a place to play. Because of this, I have made some really nice memories playing D&D. There are a lot of sad and happy stories I can tell because of me joining these D&D games. The game has not only brought me joy, it has taught me how to improvise, make stories, voice act and just the rules of the game itself, which I can now teach to others. Oh, and I am now also weirdly obsessed over dice.

The Drakenkelder itself is a very nice room, when you walk in you immediately see a lot of books from the Bellettrie library and a whole lot of different board games. The Drakenkelder is not just named Drakenkelder for show, though. On the ceiling you will find a multitude of beautiful paintings with a dragon. Then there are some tables and some couches where you can play some games, read some books, write your own stories or just talk with other people about whatever.

Fanaat and Bellettrie do not only share an association room, they

also share a Discord server. You need not even be a member of either association to join the Discord, you can just join to chat with others or to see if these associations will fit your interests. This Discord server is really useful if you want to find someone to play a game with or if you just want to stay updated on the events happening in and around the Drakenkelder. For example, if you want to be reminded when Bellettrie has its anime evenings, or if you want to know what anime is being watched during such an anime evening, you can easily give yourself a role in Discord. Or if you, for some reason, cannot find anyone to play Taipan with, the Drakenkelder has got you covered.

Originally, I joined Fanaat purely because I wanted to play D&D, which I still do. But since I have joined Fanaat I have made multiple new friends, played a lot of games and also joined the association Bellettrie for no particular reason other than that it seemed fun, and it has indeed been fun.

On the Couch...

Text: Eva van Laar and Daan van Kats

1. Introduce yourself!

C: Fun fact: I’m Cas, and I’ve been Treasurer of the 51st board.

S: I’m Sem, and I’m not cool: I haven’t done a board year.

M: I’m Matthew and I guess I’m even less cool then, but I am sitting here.

R: I’m Rick, I haven’t done a board year, but I am chairman of the (A)bac(ch)us, so hype for that.

D: I’m Daan and I’m on the couch again.

2. How long have you been sitting on this couch?

R: One and a half hour, so not that excessive.

S: I’ve only been here for 5 minutes, but Cas isn’t even on the couch.

R: He’s actually cheating.

M: Like 10 minutes.

D: Me too.

3. What is your favourite memory on this couch?

D: Smarter by the Second episodes.

S: It is a new couch by the way.

C: Yes, it’s a great couch.

S: I love the couch on the balcony more. You can sleep better on that one.

C: Although it is not allowed to sleep on it.

D: Not even a ‘middagdutje’?

R: It might be dangerous...

4. What is your favourite article in the Ideaal!?

D: This interview.

S: And board interviews.

R: Mathematical jokes.

5. What has been the highlight of your day so far?

R: Seeing you of course!

S: Probably this sandwich.

D: Sem always has good sandwiches.

S: Yes, this one is a ‘broodje gezond’.

R: So, it’s very unhealthy.

6. What will be the highlight of your day?

S: The sandwich!

D: I’m looking forward to chilling at home.

S: Is someone brak?

7. If you were in a committee together, what would that committee be called?

R: Shall you guys join the (A)bac(ch) us?

C: The Isola bella.

D: No… M: I think a committee that’s just about playing games during meetings: the game testing committee.

D: Fantastic idea.

C: That costs a lot of time.

R The GaTeCie? S: I approve. It’s KasCo-approved.

D: Then we can also be in charge of the games corner in the room.

8. What is your favourite maths theorem?

S: I don’t like mathematics, that’s why I study Civil Engineering. Maybe Buckingham π Theorem.

C: I’ve got to pick e^(π*i)+1=0.

D: You are really a mathematician.

7

C: I’m in love with pi.

R: The theorem of engineering: π=e=3.

M: Maybe Gödel's Incompleteness Theorem.

9. What is your favourite Greek letter?

C: It’s pi. I have it on my shirt here.

M: I like the zeta, because the small letter is very curly.

C: With the double loop right?

M: No, that’s the xi! The zeta has one loop. It looks really nice.

S: I cannot choose between kappa, gamma or omega. I guess gamma.

R: I use a lot of them, but no clue D: I think pi.

R: I like rho. I like writing it.

10. Can mathematics be a love language?

D: Yes. S: No. R: It is probably better than French.

D: I am sure Cas thinks so. He is a maths lover.

C: I am.

R: When you hear someone whispering things such as pi, theta and theorems, that is Cas. 11. Are you a cat or a dog person?

C: Dog. D: Same as I answered last time: cats.

R: Not dogs.

S: I hate cats.

12. Cayley or Hamilton?

D: Again Hamilton.

M: Hamilton, because I don’t know who Cayley was. Also, I do know the Hamiltonian graph.

13. Do you have Ascension Day rituals?

D: I am going to Prague. Let’s say that is a ritual.

C: I am going to cycle 150 kilometres. I think it is actually a Twents tradition: Dauwtrappen.

14. Is there anyone special you would like to dedicate this interview to?

R: To Cas, of course.

D: To the Ideaal!.

Puzzle solution: Grid Frog Text: Jorn de Jong a) If the frog has made n jumps, then those are 1+2+3+...+n=n(n+1)/2 steps. To get back to 0, you have to take as many steps to the left as to the right. The total number of steps must therefore be even. This means that n(n + 1)/2 is even, and hence n(n+1) must be a multiple of four. It follows that n or n+1 is a quadruple, that is, n is of the form n=4k−1 or n=4k. Thus, possible values ​​for n are 3, 4, 7, 8, 11, 12,... .

We are going to show that for each of these values ​​the frog can be back at 0 after n jumps. We prove this by complete induction.

For n=3 and n=4 it is not difficult to find a solution: 1+2−3=0 and 1−2−3+4=0. Now suppose we can find pluses and minuses such that ±1±2±...±m=0 for a certain integer m. Then we can also find a combination of pluses and minuses such that ±1±2±...±(m+4)=0, after all ±1±...±m+(m+1)−(m+2)−(m+3)+(m+4) =0+(m+1)−(m+2)−(m+3)+(m+4) =1−2−3+4=0.

So it follows that the frog can be back at 0 after n jumps for every n of the form n=4k−1 or n=4k. b) This assignment actually consists of two variants on part a),

8

namely in the horizontal and in the vertical directions. We start with the vertical direction. The frog makes jumps of even numbers only.

That is exactly the case of part a) but then with leaps which are twice as large. So the frog can be back on the x-axis when the last jump in the vertical direction has 8k−2 or 8k steps. So we have to investigate whether the frog can also be on the y-axis again, and thus at the point (0, 0). The last horizontal jump is one earlier or one later than the last vertical jump, so the last horizontal jump can only have 8k−3, 8k−1 or 8k+1 steps. We are going to investigate whether it is possible that ±1±3±...±n=0 for n of the form 8k−3, 8k−1 or 8k+1. To get back to the y-axis, the total number of steps in the horizontal direction are even. Since each jump has an odd number of steps, the frog makes an even number of jumps in a horizontal direction. If the last horizontal jump is of the form n=8k−3 or n=8k+1, then the total number of jumps is odd, so this cannot happen. For the remaining case n=8k−1 we use induction to show that this is possible.

Suppose the last horizontal jump

has 8k−1 steps. We show that we can find pluses and minuses such that ±1±3±...±(8k−1)=0. For k=1 we find 1−3−5+7=0. Suppose that ±1±3±...±(8j−1)=0 for a certain j>1. Then ±1±3±...±(8y−1)+(8y+1)−(8y+3)− (8y+5)+(8y+7=0+1−3−5+7=0 and so we can find pluses and minuses such that ±1±3±...±(8(j+1)−1)=0. We have now proved that we can find pluses and minuses such that ±1±3±...±(8k−1)=0 for every k.

We conclude that there are two possibilities for the frog to return to (0, 0) after n jumps. The first is for n=8k−1: the penultimate jump is 8k−2 steps vertically and the last jump is 8k−1 steps horizontally. Or n=8k, then the penultimate jump is 8k−1 steps horizontally and the last jump is 8k steps vertically.

The Pen Text: Bram Kanger We all know bees, the little fuzzy insects always flying around in search of flowers to get nectar and making honey. One of the things that distinguishes bees from other animals is that they live in big hives with a queen and that every bee has a specific job to do, which is odd since more than 90% of the bee species live in solitude, which basically means they build their own nests and don’t really make honey or beeswax.

Anyway, what I really wanted to write about is the fact that the population of these precious bees is decreasing at an alarming rate. The American honey bee population

has declined by 89% and continues to decline towards extinction.

This is due to many factors, including habitat loss, pesticides, climate change, and disease. The honey bees are now fighting for survival.

It would be a catastrophe if they lost this fight, since honey bees are responsible for about a third of the food we eat, given that a lot of crops and plants rely on the bees for the pollination of the flowers.

However, there are a few ways you can help bee populations.

If you have a garden, or you’re looking to plant one, choose to grow pollinator-friendly plants like basil, rosemary or sunflowers and avoid using pesticides. Growing these plants organically will have bees flocking towards your garden and it will help keep their life cycle going.

Another benefit of this is that you get to see a lot of adorable bees as well as other animals. You can also support local beekeepers by purchasing organic honey products.

Local bee farms prioritize nurturing bee populations.

Hopefully, bees will be happily buzzing again soon.

Olympics, but for Mathematics!?

Text: Herkus Jacina Yes, there exists an annual competition for mathematicians all over the globe.

It is known as the Olympiad or IMO. It is a mathematical Olympiad for preuniversity students and is the oldest of the International Science Olympiads in which every country sends teams of up to six students, plus one team leader, one deputy leader, and observers.

Some facts: • The first IMO was held in Romania in 1959; • Since then, it has been held every year except in 1980; • It was initially founded for eastern European member countries of the Warsaw Pact, under the USSR bloc of influence; • Later other countries participated as well; • Because of this eastern origin, the IMOs were first hosted only in eastern European countries, and gradually spread to other nations.

The problems chosen are from various areas of secondary school mathematics, broadly classifiable as geometry, number theory, algebra, and combinatorics and require no knowledge of higher mathematics such as calculus and analysis, and solutions are often elementary. The problems given in the IMO, and oriented towards creativity, and the ability to solve problems quickly. Overall, there are 6 questions where each problem is worth seven points for a maximum total score of 42 points. The competition is split into two consecutive days; each day the contestants have four-and-a-half hours to solve three problems.

Some of the people who participated in IMO have gone on to become notable mathematicians. People like Terence Tao, Grigori Perelman, Ngô Bao Châu and Maryam Mirzakhani have all participated in IMO and even eventually won awards such as the Fields Medal.

Now the fun part: this is considered the hardest IMO question ever and even the greatest mathematicians

have failed to solve it correctly.

So, are you up for a challenge?

The solution can be found in this YouTube video: https://www.youtube.com/watch?v=WCI5OaBKME4

9

Data Analysis in Sports Text: Marjolein Bolten Data analysis can be applied in various directions, one of which is sport.

With the new master track Sports Data Science, Computer Science students get the opportunity to specialize themselves as data scientists in the field of sport. In courses such as Anatomy, Applied Biomechanics and Measuring of Physical Quantities the important physical aspects of human movement in sport are Figure 1 studied. The goal of this new study tigued or not fatigued during run- that if fatigued, the knee angle of track is that the sports data scining on a treadmill. Markers were the runner is less at 40 % and 75% entists will be the closing the gap placed on the knee’s of the runner of the stride. This corresponds to between sports scientists and data and with these markers the angles the end of the stance phase and scientists. But what kind of data of the knee during the run were almost the end of the swing phase. can you find in sports? measured. In figure 1 the knee Relating this to movement terms, it In current times, almost everyone angle is shown in green when the means that when one is fatigued has a smartwatch, which can monirunner wasn’t fatigued and in blue the supporting leg will execute a tor your sleep, trainings, heart rate when the runner was fatigued. more extension movement, when it and sometimes even stress levels.

The stride of a human during run- pushes the leg of the ground. And All of this data is crucial for the perning can be divided into three pha- that during the swing phase the leg formance of athletes, in both traises when looking at one leg. The is also less flexed, and one will run ning and competitions. This data first phase, also known as the sup- with less high knees than before he shows how fit an athlete is and how port phase, is the stance where the or she was fatigued. well the athletes have recovered leg is supporting the weight of the And this is only one of the many from previous training sessions. In human. The next phase is a float possibilities within sports, data scielite training groups they perform phase, both legs are not touching ence and therefore mathematics! an extra test, like a vertical jump, the ground, and the last phase is a before heavy training sessions, and swing phase, also the nonsupport adjust training sessions according phase. A float phase ends the strito this data. This shows how imporde and a new stride can start. tant this data could be, and also how important it is to also know It can directly be seen in figure 1 what this data represents.

Another direction of data science in sports is to analyse the data obtained during the whole movement and different training intensities to see how certain movement patterns change at different intensities. For example, in my Bachelor assignment I looked at the difference in the movement of the knee when someone was fa-

10

Meme page

11

A Day With...

For this summer edition, we had the pleasure of sitting down and talking with the candidate board in order to get to know Rutger, Jorrit, Wessel, Niels and Chendo better.

Text: Lavinia Lanting and Daan van Kats

Could you shortly introduce tres from here. If you cycle to Rut- also carrying a candidate External yourself as well as your fu- beek, and you forget to turn, you Affairs phone around these days. suddenly end up in Haaksbergen, ture role?

R: Shall I start?

J: Why do you get to start?

R: Because I am the candidate Chairman of W.S.G. Abacus. Rutger van der Graaf is my name, I am 20 years old.

J: We are now very good at introducing ourselves thanks to coffee dates.

R: Yes, this is actually just a coffee date with the Ideaal!. Anyway, I come from a small village, Lutten, which is close to Attractiepark Slagharen. I like to play football. I like to have a drink every once in a while.

At the last coffee date I also said that I liked mini golf, but then suddenly three people walked away.

J: And rightly so! Now it's my turn.

N: Why is it your turn now?

J: Because my name is Jorrit Wilmink and I am sitting next to Daan and I am also the candidate Secretary for the 55th board of W.S.G. Abacus. I'm 20 years old and I’m a third year student trying to finish my thesis. My minor will come at a later stage of my studies. I come from Haaksbergen, a few kilome-

12

which is very strange. I occasionally keep for V.V. Haaksbergen and on Monday evening I must play darts.

W: I'm Wessel Heerink, candidate Treasurer. I'm 21 years old and I'm also a third year student, so I'm also working on my thesis. I play korfball in Nijverdal and I play chess. Nowadays I am also known as the knife carrier, so my name is now Messel from Kniverdal.

N: I'm Niels Berg. I am the candidate Officer of Internal Affairs and of Education. I am a second year student. I'm from Glanerbug, so don't turn your back on me, I'd say. I also play Lacrosse in my spare time and like to practice card tricks. I also have a hamster named Ed. C: My name is Chendo. I am the candidate Officer of External Affairs of Abacus and I am also a third year student. Me and Rutger both only do second-year courses, by the way. I did pass my second year, but not my first year yet. My hobbies are playing football, running and occasionally drinking a beer. I come from Megchelen, about 55 meters away from the German border. I'm

Were these the tasks and roles you were hoping to be nominated for when you signed up for the board? Why? J: Everyone has the function they didn’t want.

N: We did indeed look at the bottom of the list.

J: We've thrown everything into a top hat.

N: Yeah and then this came out.

J: And apparently this was exactly what the Advisory Council told us.

C: No, actually we just played beer pong with six different functions.

We were originally a six-person board, but unfortunately that sixth person didn't manage to get anything.

N: Yes, indeed. I had a bomb on the side.

R: Well, no, none of that happened, as you might have realized.

J: Don't say that.

R: For me Chairman was the position I had above the list. Why did I want that role? Well, I thought it would be great to lead the group

and get some experience in it. I also always try to keep an eye on everything and to make sure everyone is doing their tasks properly.

J: Yes, when we got together for the division of roles, it was actually already clear that Rutger would become Chairman and I would become Secretary. That second mainly because I was the only one who wanted to be Secretary. It also took a while to find a Vice Secretary.

W: Well, that went pretty quickly. I was the only other one who didn't absolutely hate the task.

C: We had put together a list of roles that we absolutely did not want to become.

J: But yes, Secretary was at the top of my list, because yes… I like that! A little typing, a little receiving emails.

C: Do you also think it's sexy that Daan is typing now?

J: Why do you think I wanted to sit next to him?

Who of you has the most important task and why?

C: I think I do.

R: I don't think there is a most important task within the board.

N: Besides yours?

R: I also think that nobody is the most important.

J: One team, one task.

R: Exactly.

N: Candidate ‘feut’ is a very important job though.

J: Love to Chendo.

N: Knife carrier is also not to be underestimated. I would like to do it myself, but…

much fun. We will just leave the candidate board a day before the holidays. But jokes aside, we're a bit too busy right now.

C: Well, not too busy.

R: Well, we're all busy with committees and meetings and Jorrit and Wessel are very busy graduating, but it's really fun.

J: That's exactly the problem. It's all too much fun.

N: It's just way too many things you all want to do.

What’s your typical day like as a candidate board?

J: Work work work.

C: There are two options: either wake up very early or wake up very late.

R: I have meetings almost every day: either to learn about my tasks or for committees. In between meetings I sometimes try to study, do my action points, talk a bit with members and with my fellow candidate board members.

What is the thing you are most looking forward to as a candidate board?

N: I think becoming board. I think it's nice to look forward to that as candidate board.

C: I'm actually not really looking forward to that. I actually registered purely for this candidate board period.

R: I'm really looking forward to our policy week at the moment.

C: I seriously look forward to each next day. I have something fun to do every day. I don't like to plan ahead.

away.

C: I think so for sure.

R: If it does happen, how many anytimers are on it now?

N: A lot…

C: We then have to pull something like 3 chugs in a row or something.

R: Don’t let the ‘pedellen’ know.

J: But can I just give you away then?

C: No! One team, one task.

R: I think either I or Wessel will get taken away.

N: Idea! We're going to give Thomas away and we're going to negotiate with that so that they shouldn't mess with anyone else.

How has learning about your tasks been going thus far?

R: Quite decent.

J: The current board is already familiarizing us without tasks, so it’s going well.

R: Yes. Wessel has also already had a proper training session in the morning with Eline.

W: I've spent an hour looking at the budget.

J: Mine is scheduled.

R: Mine too.

N: I'm just constantly being asked to do all kinds of things.

R: Yes, the last weekly mail was written by Niels.

N: I don't know if you noticed. I really enjoyed writing the email.

C: I've already had a session with Margriet.

Do you have certain things you hope to learn as a board member?

C: Connect with companies.

How are you experiencing R: In any case get a little insight into your candidate board what it actually is like to be running period?

Who of you is most likely to such an association, because you be braised at a Cobo? are still very much in study mode.

Everyone: Busy!

J: And way too much fun.

N: I don't really like it anymore. I'm about to leave the candidate board.

I think you can tell that I don't really enjoy it.

J: Niels and I are just having too

C: Mountain will be taken anyway and if he gets taken away, he and I are both fucked, because then we really have to drink a lot of beer then.

N: I think they will try to take me

This is quite different from studying.

J: It's also useful for preparing for work later on.

R: Yes, exactly.

W: I've also written down for myself that I can learn to be a little more sociable and outgoing. That's really

13

something I can work on.

C: It would be quite funny if Wessel is the most extroverted person on our board by the end of the year.

J: I thought the year would be all about partying, no?

N: Can we still kick Jorrit from the candidate board?

C: I want to get a bit more rhythm in my day. I no longer want to just improvise what I'm going to do every day.

Have you already been discussing about a motto or a colour as a board?

C: Yes. N: Discussion? We just had a meeting.

R: We had a meeting on Monday, but I suggest dropping by the KickIn camp if you want to know what's going to happen.

W: I suggested purple as a colour.

N: Slightly darker purple, of course.

C: A little black, so to speak. And our motto?

J: Beer! No wait, Aba? Pants out.

C: Aba? Pants out!

R: Of course it's about the band ABBA.

J: Then he will start hitting around a little with his hammer saying:"I'm not angry, I'm just disappointed".

Niels, you will be Officer of Internal Affairs. At least how Jorrit, you will be Secretary. many people can we expect Do you believe that the rest you to bring to each activity? of the candidate board will have anything useful to say C: 55? for you to take minutes of? N: No. As many as there will be neeJ: I should hope that they have some things to say about committees and the like.

N: The minutes will become a single file with only "nothing useful to say here" written on them.

J: No, it will be fine. We will simply have compact and relevant board meetings. Monday morning, Chendo. You know that, right?

C: What?

J: Our board meetings.

C: No… J: Yes. At 9 o'clock sharp. Oh no, wait, at 8:55.

C: No, just do 9:55 then.

Wessel, you are the Treasurer. Do you have any intention of transferring Abacus’ money to your own personal bank account and to either run away with it or invest it Rutger, you will be Chair- in Bitcoin? If not, how do you man. Are you confident you intend to protect the money? can keep order during the Board Meetings? How will R: Do you already have specific curyou ensure that chaos won’t rencies in sight, Wessel? ensue?

W: I think I need to get advice from C: Good luck!

R: To be honest, I'm quite confident.

As can be seen from this interview, we like to joke around in between, but if something serious has to be done, I think it can be done.

C: Indeed, our meetings are often just serious.

R: In the foreground it often just looks like a lot of fun and such, but with joint meetings and if someone has to carry out tasks, that happens quite well and quickly. I have quite a lot of faith in it, actually, and otherwise I will be very angry and disappointed.

14

a lot of money, so…

Jorrit or Chendo for that.

N: So we have to keep Wessel as a friend of course.

C: Come to think of it, I saw that Abacus had recently spent money on plane tickets to Panama.

R: Well, with a declaration form, eh!

W: In any case, I'm going to make sure that the rest can't reach the money.

J: But what if we go together to Panama?

W: You'll hear from me again. I hadn't thought about that yet.

J: Then I’ll hear from your lawyer?

R: One of the good ideas at the Good Ideas Drink was also to spend

ded per activity.

J: ‘vo N: Hopefully we will do well with promotion so that we have enough people for every activity. I noticed that sometimes promotion isn’t optimally done.

Chendo, you will be Officer of External Affairs. Do you already have a favourite partner and why?

C: Yes, absolutely. I aspire to link EasyToys to Abacus.

R: No! C: Yes! That's really the only sponsor I've thought about up until now.

J: There's just a gap in the market!

C: I think a lot of maths students will be lonely at home sometimes, so there are still a lot of opportunities to do something with that.

Jokes aside, I think EasyToys can do a lot for Abacus in other ways, such as Abacus condoms, among others.

N: That will be the Active Members Gift.

C: I also can't forget EasyJet. Of course I want our flight to Panama to be sponsored. Easyprint can also be useful. There are also just possibilities to combine all this in one big Easy sponsor: cheap flights with toys and clothing.

Niels, you will also be Officer of Educational Affairs. Which aspect of this task are you most looking forward to?

N: What I hope is to be able to finish my tasks as soon as possible during the week to also have free time to talk with members and to

deal with them as an Officer of Internal Affairs. That way I can immediately collect the opinions of Abacus members about education.

And at least how many extra resits can we expect being able to have next year thanks to you?

J: Nobody will need resits.

N: All problems in education will be fixed, so -1 extra resits.

C: No more resits!

W: Also solves the problem of when to organise them.

C: How do you plan to do this?

N: We'll see.

Who of you will be the one that will be keeping the values of Twente up high within your board?

N: All of us.

R: Feyenoord!

J: Distrust motion!

N: All five of us come from the east of the Netherlands and Jorrit, Wessel and I are even all from Twente.

R: I've decided to always speak with an accent.

N: I just don't like the Achterhoek much. Chendo is the only immigrant here.

J: F.C. Twente!

C: No, absolutely not! I can only accept De Graafschap as a sponsor.

We could watch football on Friday nights. We will all be sitting together for the FriAD anyway.

What new Abacus merch can we expect to be able to buy once you are the new board?

J: Bow ties.

C: Condoms.

R: Swimwear.

J: Abacus wash-away tattoos.

R: We can look into personalized mugs.

C: Abacus sleeping masks.

R: For candidate board members who are tired.

J: Phone cases C: Yes! J: What a good brainstorm session this is.

N: We hadn't thought about this yet, but it's going really well.

R: Daan, Lavinia, do you have any other ideas?

N: Abacus card game.

J: Chendo is the joker.

Which committees will you be in next year as members?

R: I'll stay in the (A)bac(ch)us.

J: Nor do I intend to leave the (A)bac(ch)us.

C: I'm still not sure if I want to stay.

R: Wessel and Jorrit are going to take the course to become Emergency Response Officers.

W: I'm still not sure if I'll stay in the www.com. It depends on my evening schedule.

Guiding which committee are you most looking forward to?

R: All of them.

N: Ab-Actie.

C: I can't choose.

J: Chendo, you can only choose from three committees.

C: That's still three choices.

R: I think for me the Christmas din-

15

ner committee will be really fun.

W: For me the Freshmen Committee. That's going to be fun.

J: Shall I choose a committee that Lavinia is or is not in?

C: Say the Ideaal!.

J: Should I choose the Ideaal!? No, I will go for Abaquiz.

more active.

R: I hope it'll also be a bit more standard to be on campus every day.

Any last thoughts you would like to share to the reader?

R: I hope they got this far.

Which committees will you C: You can always come to us for a be guiding next year? nice chat.

R: The Cantus committee, the Christmas dinner committee, the PixCie, the BataCo, the CoCo and the Advisory Council.

J: The CuEC, the Ideaal!, the prom committee, the Symposium committee, the WHALE, the Sports Day committee and Abaquiz.

W: The www.com, the Freshmen Committee (FMC), the Auditing committee and the Twick-In 2022.

N: The (A)bac(ch)us, the Ab-Actie, the Collage committee, the Dies committee, the Education committee and the (h)ERO. C: RSA, EWI-trip and the Twick-In 2023.

Which committee that you are currently in will you miss most next year?

N: The Twick-In. C: The FYASCO! R: The Twick-In, because I'm still going to be in the (A)bac(ch)us.

W: The Parents Day committee, although I will get to experience that with the FMC as a board member.

J: The Twick-In for me as well.

What are your hopes for Abacus for the coming year?

C: That it will be a fun year and that we will get active and fun freshmen.

W: No monkeypox.

C: No Corona either.

C: I also hope that there will be a lot of contact between the different years and not just within the year layers and that the current second year students will become a bit

16

N: If you have anything to add for next year, send your ideas to candidateboard@abacus.utwente.nl.

J: Or to cb@abacus.utwente.nl or to kb@abacus.utwente.nl.

N: Or to feuten@abacus.utwente.nl.

That one also works.

R: We clearly like to joke around, but thank you for reading.

J: Whoever reads this must chug a beer.

Week Afsluitend Leesvoer Voor Innemende Studenten

Friday maybe when you read this

WALVIS

Issue #5?

Bringing you the latest news, columns and puzzles

Column

Hey there column in the Well, I am actually not even sure whether you can call this a guest column with our own complete lay-out, awesome whale pictures, puzzles and of course the lovely Werner. What should we call this then, publicationsidelined to envision myself with a synonym I invariably resort to thesaurus.com in the interest of enriching my glossary with gratuitous features.

Works wonderfully for study projects as well. verreach it though.

But how can we even publish a WHALE when it is not even the end of the week? Well again we are also not really sure Even the issue-numbering is totally messed up. Did the last ½ publication and this WHALE not published as WeekAfsluitend Leesvoer count as full issues or not? important things in life. Also to compensate for these unfortunate facts and not punish you to hard with a very difficult puzzle that normally satisfies your end-of-the-week thirst, we only give this very rewarding drawing puzzle that should still satisfy your SOG-desires in the final stages of this lovely module.

Damn, it is in fact already the end!

Maybe that explains all the unexplainability and uncertainty in this column. For me, it is definitely time for the holidays and just have nothing on our minds for a while (insofar that is even possible). Luckily, not only Werner can help you will relax with lovely leesvoer, but also the help you relax with an awesome puzzle booklet.

I myself will happily enjoy this summer holiday as the final terror of graduating is approaching. I am happy I already know my nephew the terror whale as a mental preparation Now as you can see we have a lovely committee job advertisement available as this will almost be my last column in a while. Coming Friday the 1st of July will also be our last publication of the academic year so be sure to join this awesome drink! Best of luck to you with finishing up the last exams and assignments and see you there.

By the WALVISSEN*: Sem Geerts Editor in Chief Cas Sitvast - Columnist Fleur van Alphen - Writer Wout Leemeijer - Puzzle Developer walvis@abacus.utwente.nl

*WALVIS Schrijf- En Nieuwscommissie

Travel diaries are awesome Werner loves to write, and therefore makes sure to think of enough reasons to write during the summer holiday. One of his favourite writing-projects is his holiday journal: a diary in which he writes all of his adventures and makes fun drawings or pastes fun pictures. To enrich your vacation, Werner has summarized a few great tips for your own holiday journal!

Take an old notebook and pimp the outside with glitter, paper, pictures or a map of the country you visit.

Begin your notebook with planning part of your holiday. If you already know beforehand what you will visit, the visit will be more memorable.

Insert a packing list. This way you will make sure not to forget anything. And Werner has experienced that it also helps with insurance in case your suitcase gets lost.

Think about the title of each diary page. Instead of writing the date, you can write the name of the city or the highlight attraction that you visited.

If you, unlike Werner, don't like to

Pimp the content of the diary by making fun pages. You can make a holiday bucketlist, a list of all people you meet, a map where you show the route you travel or write the fun new words that you learned in the local language. Also make a list with your favourite restaurants, local dishes and local music.

Do you meet people on your journey?

Make sure to let them write something for you in your diary. This is a fun way to remember all your new friends!

In case you are very proud of your diary, you can even send Werner part of your journal and maybe it gets posted in the first Walvis of the new year!

write the best memory of every day, paste a picture below it or make a drawing.

Job advertisement Sadly, some of the WALVISSEN will probably leave for a little while, spread their beautiful fins and swim out to other waters and have an adventure in the other parts of the country. Some new fish in the seas can come and join our adventurous group. Do you think you have what it takes to join the wonderful whales, then check the requirements next.

Do you love to join awesome FriAds, are capable of writing random stuff that no-one truly reads with great attention, or are really patient with Word and willing to spend too much time perfecting this wonderful design?

Then feel free to send us an email or notify the board!

17

Weekly Handout of Alcoholic Leisure and Entertainment

Friday (possibly)

18 Scribblers *WHALE

WHALE

Issue #5?

Chain Interview Text: Lavinia Lanting A chain interview is an interview of a very peculiar format. A member of the Ideaal! thinks of a question to be asked to a random person. The person being asked not only has to answer the question, but must also think of a new question, which will then be asked to some new random person. This continues until the interview then ends when the member from the Ideaal! who had first thought of a question answers the very last formulated question, such that the circle is completed.

This is how it went.

enough you could let your opponent suffocate.

What is the funniest thing that's happened to you this week?

How does a monkey open a banana?

Mariya: My life is not funny. I am graduating.

Jorn: From the bottom.

What did you have for lunch on Tuesday 14 June?

If you could be a taste of tea, which one would you be?

Tim Zijlstra: 1. In particular, if indicated with the left index finger.

Raymon: Caramel Vanilla, because I'm so sweet.

Which fictional character would you like to be and which one would you probably be?

If you could be any location at campus, which one would you be and why? I myself would be the Cubicus, because my mind is half burnt and nobody knows how to navigate me.

Emile: I would probably be Kazuma from Konosuba, I'm afraid. I would like to be Ash Ketchum.

Leanne: the Drakenkelder, because it's objectively the best place on campus.

What is your favourite fruit and which one is your least favourite?

What is the most special thing your body can do?

Anouk: My favourite fruit is Melon, when it's season for it, at least. My least favourite is the blackberry.

Pelle: Ask your dad.

What's on your shirt currently and why would it fit the person sitting next to you?

Alberto: It's the logo of the martial arts I do back home, which is a mix of older and newer types of martial arts. It would fit Nick because it's a shade of blue and he seems to wear a lot of blue t-shirts.

Out of the three pieces of food you got for the break during the sports day (a banana or apple, fruit crackers and vitamin water), which one would you utilise to defend yourself from an aggressor and why?

Lars: The apple. You can throw it very nicely and if you aim well

Why are bananas bent?

Jeroen: If they would be standing up straight, then they would fall down.

If 420 is a good number, which one is the best?

What is your prediction for the year 2050?

Eva: I would hope to be married by then. I predict that the climate crisis will rage on and kill a lot of people. Maybe doctors will have figured out how regrow limbs and we might be able to grow meat in factories. I also hope I will have owned at least a cat and a crested gecko by then.

What is the luckiest thing that's happened to you this week?

Anna: last Sunday, during my 1500m run I managed to not get surpassed by the last person. For the first 1200m I had a good lead on her, but then she started sprinting, so I had to sprint as well and I managed to stay ahead by like half a second.

Jasper: a frikandelbroodje from the Coop.

How many beers did you have during the End of Year Activity?

Chendo: Too many. I think most probably 15.

If you could be an animal for one day, on which day would that be?

Jonne: On King's Day, because if you could be a lion then, it would be cool.

If you were a ball, which sport would you then be playing?

Jorrit: Marbles.

Did you use sun cream today?

Daan Pluister: Yes! What did you think of the Sports Day? Jorg: It was fun, but my performance could have been better.

Would you rather have cat whiskers or cat claws and why?

Lavinia: I think I would rather have cat whiskers. In spite of the fact that I think having retractable claws would be pretty nice, I keep imagining my fingers without nails and just one tiny spot from which claws can appear and I hate that image.

19

Just Abacus

20

Things...

21

Interview: Lotte Weedage Text: Diana Dalenoord networks. I work in a real women’s power team because in addition to Clara, I also get a lot of support from Suzan Bayhan, who works in Computer Science and has taken me into the world of 5G. My promotor is Nelly Litvak, who was recently declared UT Teacher of the Year 2022.

Research into the effects of 5G My PhD research is also about large networks, in line with my master's assignment. I am looking at wireless networks in 5G, which has more features as 4G and 3G, such as multi-connectivity, where people use multiple base stations.

Passing on my love and pas- on large networks, such as Facebook and Twitter. I investigated sion for science and maths

22

With a mother as a maths teacher, this discipline is almost a way of life for Lotte. She really enjoys maths, giving presentations, teaching and doing research. If there is a maths gene, Lotte has inherited it from her mother. Lotte is currently a PhD candidate. In addition to doing scientific research, she teaches Linear Structures and supervises students on their bachelors’ assignments.

the nodes (people) and edges (follower/friends) in these networks and tried to find groups (clusters) of nodes. In a small network, you can find these clusters by using simple, deterministic algorithms. For larger networks with more than 100 million people, this costs too much memory and for that, you need to use an approximate counting algorithm such as HyperLogLog. This algorithm helps you to find these clusters in a quick and memory-efficient way.

Why did you choose to do PhD research?

During my Master’s assignment, I worked on finding clusters within large networks by using the HyperLogLog algorithm. This is when I got a taste for research and especially

After graduating, my interest in this field grew and I was very happy with the opportunity to do PhD research under the supervision of Clara Stegehuis, the expert in the areas of probability theory and stochastic

Wireless mobile communication, such as 4G and 5G, uses frequencies in the electromagnetic spectrum. Compared to 4G, 5G provides faster data transfer, shorter response time and more reliable connections. The applications that are possible with 5G work on all frequencies, but because the lower frequencies are in use by 3 and 4G, 5G works on the higher frequency band. The lower frequency band is suitable when there are many users with little data transfer such as Internet of Things (IoT) applications, from smart home energy meters to agricultural sensors. The 3.5 GHz band is most suitable for com-

bining a high data rate with good coverage. It provides a higher data rate at the local level and is therefore suitable for many business and consumer applications that need high-quality video or image, such as Virtual Reality, high-resolution video and 360-degree video. A disadvantage of this frequency band is that it is more difficult to achieve coverage in buildings; the signal is more easily blocked by walls, windows, trees and even people.

In addition, more base station locations are needed because the range of the antennas is shorter.

I am currently researching what happens when everyone is connected to several base stations. It has quickly become apparent that this was not a good thing, because when you are further away from your base stations, your internet quality decreases. A base station has a maximum of resources that can be shared. If many users are far away, the connection deteriorates, and then you experience bugs when watching videos or WhatsApp messages get stuck temporarily and are sent with a delay. In short, the internet becomes much slower. I am doing research on how we could exploit 5G such that everyone can benefit from it. Especially for VR or AR this is necessary, as these applications need a very reliable and fast internet connection, which cannot be delayed or blocked!

The resilience of the Dutch internet

Sometimes, during your research, you run into other problems. This was the case with the question of how reliable the internet is in the Netherlands in the event of earthquakes, floods or power out-

ages. Who will still have a (good) internet connection if the base stations have been damaged or been switched off by a short circuit? During such events, many people will need to use the Internet and make mobile calls at the same time. To find out how reliable the internet is during a natural disaster, you have to make a model/graph of the data of base stations and locations. This is really fascinating to investigate.

Teaching is part of UT-PhD work PhD work is absolutely not boring because you can pick up different research projects within your PhD study. At UT, PhD students also get teaching tasks. Giving presentations on mathematical topics and passing on your own knowledge to students has always interested me.

I chose the Minor 'Leren Lesgeven’ to see if this would be something for me, which I can answer with a clear 'yes'. That is why I also did the Master’s in Science Education and Communication in addition to my Master’s in Applied Mathematics. This knowledge comes in handy now, because I am giving the course Linear Structures, together with Nelly Litvak. Nelly gives the lectures and I take care of the tutorials.

I also supervise a number of bachelor students on assignments I have given them. I often think back to my own bachelor’s assignment that I did for the Solar Team. At the time, I was working on a racing strategy for the solar car, which was supervised

by Jasper Gosseling. It is really fascinating to see how someone develops during this programme. What I knew then as a bachelor’s student and what I know now as a PhD student is of course a world of difference.

I like using my current knowledge to encourage bachelor students to look in the right direction for answers to carry out the assignment.

I am really happy with my choice for PhD research and the work that comes with it. Although I don’t know exactly what I want to do after this, I would like to continue working partly in science, and also partly as a maths teacher in the classroom so I can enthusiastically pass on my knowledge to others.

23

Do you have a minute to talk about INRs? Text: Dieuwertje Alblas Motivation Image processing is an extensive and we l l - e s t a b l i s h e d field in mathematics.

Classic problems include image classification, segmentation, and registration. All mathematics involved is handled by a computer, as image processing is very computationally demanding. To process an image in a computer, we first need a proper representation; generally, digital images are represented as signals on a discrete grid. An image I can therefore in principle be seen as a big matrix: I ∈ RH×W,where H and W are respectively the height and width of the image and define its resolution. The entries of I represent its pixel intensities. In reality, an image is a continuous signal on a continuous domain. This has several consequences: • Preserving all the fine details after discretisation demands a very high resolution of the digital image. This uses a lot of memory to store and process the digital image.

• When taking derivatives of the discretized signal, we have to approximate this numerically using a weighted average of each pixel and its neighbourhood.

In this article, I will explain implicit neural representations (INRs); a relatively recent development in the field of deep learning. INRs have shown impressive results in representing continuous signals12. Instead of explicitly storing the image in a uniform grid, we parameterise the continuous signal implicitly in a neural network. Besides compact

24

storage of high-frequency signals, this has numerous applications: creating novel 3D viewing angles from 2D images3, continuous alignment between medical images4 and improved CT reconstruction, and improving CT and MRI image reconstruction from sparse sampling5. Before we get to what an INR is exactly, I will cover some prerequisites.

Neural networks The basic building-block of a neural network is a so-called perceptron or neuron, as depicted in Figure 1a.

A perceptron is a nonlinear mapping from the input space to a scalar. The perceptron takes a couple of scalar-valued nodes as input, in this case x = [x1, x2, ..., xM]T The perceptron has a set of weights [w1,w2, ...,wM]T that is used to compute a weighted average of the input. The perceptron also has a bias b that is added to this weighted average. Finally, a nonlinear activation function σ is applied. In Figure 1a, a rectified linear unit (ReLU) function is shown, but in practice there are many options. An important requirement is that σ is differentiable.

Perceptrons are rarely seen on their own; combining them into a multi-layer perceptron (MLP) makes them more powerful. As the name suggests, an MLP consists of multiple layers; an input layer followed by k hidden layers (hi) and output layer. A schematic drawing of this architecture is shown in Figure 1b. This is a feed-forward ar-

3. B Mildenhall et al. “Nerf: Representing scenes as neural radiance fields for view synthesis”. In: European conference on computer vision. 2020.

4. Jelmer M Wolterink, Jesse C Zwienenberg, and Christoph Brune. “Implicit Neural Representations for Deformable Image Registration”. In: Medical Imaging and Deep Learning. 2022.

5. Liyue Shen, John Pauly, and Lei Xing.

“NeRP: implicit neural representation learning with prior embedding for sparsely sampled image reconstruction”. In: IEEE Transactions on Neural Networks and Learning Systems (2022).

chitecture, meaning that the output of each layer serves as an input for the next. Every layer contains multiple perceptrons, each of them with their own weight vectors and biases. Instead of calculating the output of each neuron separately using these weight vectors, we construct a weight matrix Wi for the entire layer. The output of each hidden layer hi is then given by: where h0=x. The nonlinear activation σ is performed elementwise.

The last hidden layer hk produces the output vector y; its activation σ might differ from the hidden layers.

Neural networks can be used to represent numerous mappings from RM to RN, as their weights and biases can be adapted in a process we call training. For training a neural network, we require a dataset with samples consisting of a feature vector Xi ∈ RM and an observation Y i ∈ RN. The exact relationship between the features and the observation is not known, but we try to embed this into the network during training. The training procedure consists of a number of steps: 1. Forward propagation: the network gets a number of feature vectors X from the dataset, called a batch, forwards them through its layers and predicts an output Ŷ for each feature vector.

2. Calculate loss: from the dataset, we know the observation Y belonging to each feature vector. We can thus measure the discrepancy between the objective output and the prediction of the network using a loss function L. This function takes on a high value if the discrepancy is big; the objective of training is thus to minimize this loss function. Many different loss functions can be chosen, depending on the task of the network, as long as L is differentiable.

3. Backpropagation: This is the step where all the magic hap-

(b) (a) 2 Figure 1: a: Architecture of a perceptron, taking an M-dimensional input vector and mapping it to a scalar. b: Architecture of a multi-layer perceptron, taking an M-dimensional input vector and mapping it to an N-dimensional output vector.

pens: this step determines the update of the weights. We use gradient descent to optimize L. As both the loss function and all operations inside the network are differentiable, we can determine the gradient of the loss function with respect to all the weights in the network. We update the weights by taking a small step in the direction of the gradient. The size of this step is a pre-set parameter we refer to as the learning rate.

During training, this cycle repeats numerous times; the network receives different batches from the dataset to perform its predictions on. The network is trained for a number of epochs, meaning the number of full passes of the entire dataset through the network. When all the epochs are completed, we hope that the layers in the network ensure a reasonable mapping between X and Y . What we mean by this is that for a new feature vector, that was not part of the dataset, the network can give an accurate mapping to an observation Y. This is what is so powerful about neural networks, once they are trained properly, they generalize well to new and unseen samples. Of course, this is not a hard guarantee, as this is highly dependent on the data, network architecture, loss function, choice of optimizer, learning rate, etc. A lot of literature exists on generalization of neural networks and encountered problems in that area,

such as data bias and overfitting.

Good starting points for learning more about neural networks and some of their limitations are the books by Aggarwal6 and the one by Goodfellow et al7.

Implicit representations Now we understand the basic principles of a multi-layer perceptron, we can move on to implicit representations. The main idea of an implicit neural representation is that we use a neural network to represent a continuous signal. Taking the image example from the introduction, we have a 2D image I ∈ R3×H×W of size H×W, with three colour channels (RGB). Let I(x) denote the RGB intensity at image coordinates x=(x1,x2). We can parametrize a neural network, 6. Charu C Aggarwal. “Neural networks and deep learning”. In: Springer 10 (2018), pp.

978–3.

7. Ian Goodfellow, Yoshua Bengio, and Aaron Courville. Deep learning. MIT press, 2016.

denoted by f(x,θ), taking the image coordinates as input and output the RGB intensity at that location, as shown in Figure 2. The neural network’s weights θ can be optimized on a dataset containing the pixel samples and their corresponding intensities by minimizing the mean squared error loss: I fit a SIREN network2 to a downsampled version of the picture of my dog given in Figure 2. The SIREN networks are multi-layer perceptrons that use sine functions as their nonlinear activations. I used the mean squared error loss function as in the equation above with a learning rate of 1e-4. The resulting loss curve is shown in Figure 3a, together with some reconstructions at a few moments in training.

After training, I have reconstructed the image at two different resolutions, using the same network, this is shown in Figure 3b. This is pos-

Figure 2: Implicit neural representation for an image of a good dog, taking a location (x1, x2) as input, and outputting the RGB intensities at that location.

25

sible, because the neural network represents our image implicitly.

Therefore, the notion of resolution does not apply to implicit neural representations; if we have a neural network that is trained to represent the signal, we can evaluate the signal at any resolution. However, it is still challenging to implicitly represent images with a very high resolution (> 1e9 pixels) and high frequency details8.

Additionally, we can determine the gradient of the neural representation, without inference of numerical schemes, as our neural representation is fully differentiable. Meaning, that if we know properties of the gradient of f(x), we can also train the neural network to match the gradient and find its primitive. That is shown for representation of images and even solving some partial differential equations in Vincent Sitzmann et al2, but also for implicit representations of 3D objects in Amos Gropp et al9. In the case of the Siren networks, the activation functions are periodic, hence their 8. Julien NP Martel et al. “Acorn: adaptive coordinate networks for neural scene representation”. In: ACM Transactions on Graphics (TOG) 40.4 (2021), pp. 1–13.

9. Amos Gropp et al. “Implicit Geometric Regularization for Learning Shapes”. In: International Conference on Machine Learning.

PMLR. 2020, pp. 3789–3799.

gradients are also periodic functions; that means that we can also use higher order gradients of the signal to train our network.

One big limitation of implicit neural representations is their generalizability. In the examples we have seen until now, we have used a neural network to represent a single image or function. If we want to represent another image or another sample, we need to train a new network. To tackle this, we can use conditioning; this means that we can represent each picture as a low-dimensional feature vector, that we give as an additional input to the network.

So, for example if I were to use the network from Figure 2 to represent multiple images, the input (x1, x2) would be extended by a feature vector (x3, ..., xM) to let the network distinguish between different images. Park et al.10 show in their work that it is possible to implicitly represent classes of 3D objects using a single neural network.

represent signals of all sorts. I have shown a tiny part of what is possible with INRs; I hope this article has sparked your interest to explore them! A lot of code is publicly available and it is fun to play around with your own data.

So in conclusion; after reading this, you have an idea of the mechanism behind neural networks, and how they can be used to continuously 10. Jeong Joon Park et al. “Deepsdf: Learning continuous signed distance functions for shape representation”. In: Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition. 2019, pp. 165–174.

(b) (a) 2 Figure 3: a: MSE loss values during training of a SIREN network to a downsampled version of the image from Figure 2. b: Trained SIREN network evaluated on grids of two different resolutions.

26

Vacation Map Text: Lavinia Lanting Discover where Abacus members will be spending their summer vacations!

27

Interview

We had the honour to interview Thomas, Eline and Margriet one final time in their roles of members of the 54th board of W.S.G. Abacus.

Text: Jorg Gortemaker and Tim Hut

What did you want to beco- what you're doing. Then at a certain T: I think partly. I have organised point you get into the flow and it be- events and you work together with me when you were kids?

E: I think I wanted to go to the Olympics as a gymnast, but I didn't succeed.

M: It depends on when you asked me as a kid, because I wanted to be a photography teacher one day, but I also liked the idea of becoming a ballerina. I also thought about becoming a vet.

E: Oh, I wanted to be an interior decorator.

M: I think there were more, but don't remember them right now.

T: I wanted to be a heart surgeon and then I found out that I didn't really like things with blood, so that was unfortunate. Then it didn't become that.

Jorg: And your alternative? You had no alternative?

T: No, I was just like "then not, shit."

There it goes…

comes less busy. But then Corona came again and eventually it went away and we suddenly started catching up many activities, and yes...

M: Now it's very busy.

E: Yes, it's very busy now.

T: At times it was quiet and now it's super busy, so it's a bit of both. I expected a bit of the middle ground but there is more fluctuation than I expected.

E: But the Corona time was also funny, then we would throw gigantic paper planes from the balcony, because there was no one in Educafé anyway. We certainly entertained ourselves.

Jorg: The board weekend also has been a lot of fun then, talking about Corona.

T: Hahaha, certainly.

M: Yes, but it was a lot of fun.

Has your board year given What was it like being the you more perspective into board? Was it easier or har- what ‘working life’ is like? der than expected?

E: It was kinda strange actually. We had never really worked together as a group and you really have no idea

28

M: For me it did, but it could also be that that is more of an External Affairs thing.

E: I don't think so per se.

people who all do other studies and who are all board members.

It is quite an experience when all people have different visions and to work with them you do learn things.

E: You do learn to collaborate with many different parties and people and to communicate.

What was the nicest moment during the board year?

E: I still think it's kind of funny that over spring break we were all three here, just in the room, for no reason really. Then we received a message from someone from the study association from Amsterdam: “Who wants to play Centurion?” And then Martijn was like, yes you should and then we spontaneously did that. After playing Centurion we killed time until the first train went back and everyone was completely dead and Thomas was way too happy.

M: And the next morning we had an intake interview for the board training.

E: Margriet was really dying.

M: I was dying so badly. I also enjoyed making the cheesecake in

the Abacus room.

E: We had to make a cheesecake for the VB staff as a thank you. We started doing this together after a policy plan meeting and then we didn't have a springform pan, so then we made it out of cardboard and that was really funny.

M: It just turned out to be a good pie.

E: We didn't have any whipped cream, so we improvised it with yoghurt and whipped cream from a spray can. It really was the biggest improvisation show there was.

M: But it tasted fine.

T: And I really really enjoyed the SU board weekend.

M: Very nice to be very hungover together in the morning.

What has been your favourite activity so far?

M: I really liked the symposium and I just had something else…

E+T: The Christmas dinner was a lot of fun.

M: A little less fun after that. Oh yes, I also liked the poker tournament, I'm also glad it turned out well.

E: I also liked the Parent's Day. I wasn't there myself, but I heard afterwards that everything went well, so I was really happy with that.

M: The (D)ET day was also great.

M: I also liked AMW and DRAMA.

T: Yes, but I'm going to go to DaVinci on that day.

E: The KasCo.

What are your hopes for the M: Maybe, just maybe the symponext 10 years of Abacus? sium committee again. I thought it E: That members wash their dishes.

M: That people stay active.

E: That people feel at home.

M: I'm happy with how Abacus is now, so that it stays this way. Play games in the Abacus room.

T: That they continue to organise a variety of activities.

Any tips for the candidate board?

T: Get plenty of rest.

E: Yes, take care of yourself, enjoy and have fun. Communication is key.

T: stay positive, E + M: Positivigeit!

was a really cool symposium.

E: I haven't thought much about it yet.

M: I'll probably stay with the PixCie. T: Maybe back to the Education committee, but at the same time it might be more fun to do a new committee. I'm not really sure what a new committee would be.

M: Sports Day is also fun. There are plenty of nice committees.

E: Then the year after we're going to do DIES, right?

M+T: Yes!

Which committee was the most fun helping out?

M: Cantus committee was nice and Pixcie of course. Actually all committees. The Symposium committee was fun too.

E: The Ideaal!, the (D)ET day because those people were a really big meme and Parents Day in the beginning.

T: I think the Twick-In 2022.

What are your plans for next year?

Your board year is not quite finished. Anything you’re still looking forward to?

T: The End-of-Year Activity, today!

M: And the Sports Day, tomorrow.

T: And the Kick-In. E: And the Cultural Evening. And the theme drink on June 29.

T: The ICOS Culture Fair. I'm looking forward to that on Saturday.

E: Summer Sounds.

Jorg: I want to hear one more answer from the board representative of the Ab-Actie and then we can move on.

E: The Big Activity!

Jorg: Yes, thank you.

Are you joining any (new) committees next year?

What are your plans for next year?

M: Study.

T: Finish my Bachelor's degree.

E: I hope to start my Master's and I plan to become a board member of the Dutch Student Gymnastics Union, but that's not much. That means meeting six times a year and lots of drinks and fun.

T: Also organise a study trip.

M: Studying.

T: Finish my Bachelor's degree.

E: I hope to start my Master's and I plan to become a board member of the Dutch Student Gymnastics Union, but that's not much. That means meeting six times a year and lots of drinks and fun.

T: Also organise a study trip.

What was your greatest achievement this year?

M: I think the number of active members has gone up quite a bit.

We did our best to make that happen.

E: Educafé is always mostly filled

29

with Abacus members. Oh, also the new cookie closet!

M: New table, new TV. T: I have something in my head but I don't know what the word is. I just thought of something and then I was like “huh...”. Oh yes, that whole monthly calendar, that there can be activities at all. So many and that somehow there are always enough emergency responders, magically.

Always months full with an Abacus activity every day and then it's just planned that way. Then I really do say “It worked!” That's nice.

Jorg: That sounds like a shortage of emergency response officers?

M: Unfortunately it doesn't work that way.

T: We are not offered enough emergency response courses.

M: It's not our fault, though.

T: But if people have a BHV certificate you can always send an email to intern@abacus.utwente.nl and then you might end up on the BHV committee. Very very ‘gezellig’.

What will you miss about being on the board?

E: Being able to leave all my stuff randomly in the room.

M: I liked having my own workplace, I like it. And you get to control the music.

E: The random afternoon walks around other associations when you're bored and random board members yelling 'There's lunch in this room!' and then a random group of board members suddenly come to that room.

What will you definitely not miss about being on the board this year?

T: Running the Room.

M: I don't think people know exactly what it means. The most annoying thing about running the room is washing mugs.

T: Being in the room on time. People who get mad that you don't do something, while you just don't

30

feel like doing literally anything, because you think I can just sit in the room and work and then all the time members whine that things aren't done.

E: Whining members who expect you to do everything in two seconds.

T: I'm really not going to miss that: nagging members.

Would you consider ever doing another board year?

M: Yes. E: Here or somewhere else?

Jorg: Just another board year.

M: Yes, I do, but not full time I think.

T: Board at the RSA. Or (A)bac(ch) us board.

What are you looking forward to in the coming year?

T: Taking courses, just having lectures again.

E: Sleep.

M: Just going to activities and then having no responsibility.

E: Oh yes, but I don't think I'll be able to do that yet.

M: Mainly drinking enough.

T: Oh yes, the EEMCS trip was great fun too!

M: I say drink and you immediately think of an EEMCS trip.

Any last thoughts?

E: Yip yip.

Summer Recipes Text: Lavinia Lanting Cooking is a great passion of mine and how could it not be? As in Italian, I have been learning how to cook since a very young age and I am not shy when it comes to experimenting with new dishes: the recipe may suggest something, but eventually I will always give it my own spin, be it by swapping some ingredient, or by switching the cooking technique being indicated.

What never changes, though, is my source of inspiration: giallozafferano.it (which nowadays has an English version containing almost all of the recipes present in its Italian counterpart, so feel free to take a look at it if you yourself are looking for inspiration when cooking). This beautiful website contains thousands of recipes from every corner of Italy, with new ones being added daily. The recipes are detailed and easy to follow and the website allows you to easily look up dish sorts to fit your every need.

Since the summer is finally here and the sun is shining brightly as I am writing this, I thought it would be a great idea to try and inspire you with some (relatively) simple and fast vegetarian summer recipes that I believe you might enjoy.

Small zucchini pizzas Now move onto the toppings.

Take a bowl and mix the tomato puree with salt and oil in it.

Wash the other vegetables and cut them into pieces, then grill them.

Cut the mozzarella into pieces and place it into a strainer as to let it leak for a while.

Now wash the cherry tomatoes and cut them into pieces.

Peel the onion and cut it, as well as the smoked scamorza, into thin slices.

Ingredients for 9 pieces • Zucchini 450g • Parmesan cheese 50g • Basil • Black pepper • Potato starch 100g • Eggs 1 • Salt Ingredients for various toppings • Tomato puree 120g • Yellow bell peppers 50g • Buffalo mozzarella 100g • Smoked scamorza 60g • Salt • Eggplant 50g • Zucchini 60g • Cherry tomatoes 50g • Red onions 1/2 • Olives 20g

• Olive oil Preparation Wash the zucchini and remove the edges, before grating them. Place the grated zucchini in a bowl and add the egg. Add then salt, black pepper and basil to choice. Also add the potato starch and parmesan cheese before mixing everything together.

Place slightly oiled baking paper onto some oven trays and flatten the mixture on top of the baking paper in the shape of disks of about 12-15cm diameter. You should be able to obtain 9 such disks.

Warm up a static oven at 180°C and, once the oven is warm, cook the obtained disks for 8 minutes.

Pick up the zucchini disks again.

Top three of them only with the tomato puree and another three with the tomato puree, the mozzarella and the cherry tomatoes. Top the final three with the smoked scamorza, the onions and the olives.

Salt them and add pepper to choice and then place them back into the oven for another 15 minutes. Once out of the oven, top the three with just the tomato puree with the grilled vegetables.

Your small zucchini pizzas are now ready to be served!

31

Summer risotto •Salt •Olive oil •Pecorino cheese 30g

Ingredients for 4 portions • Risotto rice 280g • Rocket salad 70g • Vegetable broth 1l • Black pepper • Yellow bell peppers 260g • Red onions 1/2

Preparation Wash the bell peppers and place them into an oven tray covered with baking paper. Cook them in an oven warmed up at 240°C for 40 minutes, until they are charred. Place them then into a bowl, cover it with cling foil and let the bell peppers cool down. Once the bell peppers are cold, remove the peel, cut them into pieces and set them aside. Keep aside the moisture released when cutting them.

Grate the pecorino cheese and set it aside.

Warm up the broth. Cut the onion into tiny pieces and add it to warm oil in a deep pan. Fry it for a few minutes, then add the rice and let it toast, making sure to continuously mix within the pan. Add the moisture from the bell peppers and mix, then add a few ladles of broth. Add salt to choice and add broth whenever needed. Halway through cooking the rice, add the rocket salad and set the fire to a medium flame.

Once the last ladle of broth has been added, add the bell peppers, mix and put our the flame. Add then the some oil and the pecorino chees and mix well.

Your summer risotto is now ready to be served!

Gazpacho with summer fruit and vegetables

Ingredients for 4 portions • Strawberry 450g • Red bell peppers 115g • Black pepper • Cherry tomatoes 250g • Red onions 1/2 • Salt • Olive oil 50g • Celery 60g Ingredients for the tempura • Red onions 215g • Sparkling water 100g • Rice flour 70g • Salt

32

Garnishes • White yoghurt • Black pepper • Basil • Olive oil

set them then into the warm oil.

Cook them until they are golden and set them then onto a tray covered in kitchen paper, then sprinkle them with salt.

Preparation Wash all the fruit and vegetables.

Peel the celery and cut it, as well as the bell peppers, into pieces.

Remove the leaves from the strawberries and cut them into pieces.

Half the tomatoes and cut the onion into pieces, then put everything into a bowl. Add oil, salt and pepper and puree everything with a mixer.

Add water to make the mixture creamier, if necessary, cover it with cling foil and set it in the fridge.

Pour now the gazpacho into deep plates and garnish them with yoghurt, pepper, basil, olive oil and the onion rings.

It's now time to take care of the tempura. Peel the onions and slice them, making sure to separate the rings within a slice. Mix the rice flour and sparkling water until the mixture is uniform and warm up some oil in a pan to a temperature of about 170°C. Set each ring into the mixture of flour and water and

Summery strudel with peaches • •

Ingredients for 8 portions • Flour 150g • Water 30g • Eggs 1 • Salt • Olive oil 10g • Butter 40g Ingredients for the filling • Peaches 1kg • Pecan nuts 70g • Butter 50g • Bread crumbs 100g • Brown sugar 50g

Lemon zest Vanilla extract 1tsp

Preparation Place in a bowl the flour, water, egg and oil. Add the salt and mix everything first with a fork and then by hand. Transfer the mixture to a table and work the dough until it is smooth and elastic, then make a ball out of it, place it in a bowl, cover it with cling foil and let it rest for 30 minutes at room temperature.

While the dough is resting, take care of the filling. Melt the butter and set it aside to cool down while you peel the peaches. Remove the pit and cut the peaches into small cubes, then place them into a bowl and add the brown sugar, the bread crumbs and the melted butter, then mix everything together. Add now the vanilla extract, the lemon zest and the pecan nuts and mix, then set it aside.

Melt the butter and place the dough onto a floured cloth. Add some more flour and then roll out the dough into the shape of a rectangle. Finish rolling it out by hand and then delicately brush the dough with the melted butter. Place now the filling onto the left side of the dough, but make sure to leave some space from the edge. Fold the empty space of dough onto the filling and close up the sides. Helping yourself with the cloth, roll the dough with the filling, until you obtain a cylinder, then seal the edges.

Transfer the strudel to an oven tray covered in baking paper and brush the strudel once again with butter, then place it into a warmed up oven at 200° for 35 minutes.

Your summery strudel with peaches is now ready to be served!

Summer Calendar Events Text: Lavinia Lanting

08/07/2022 - 10/07/2022 08/07/2022 - 17/07/2022 08/07/2022 - 10/07/2022 19/07/2022 - 22/07/2022 22/07/2022 - 31/07/2022 26/07/2022 - 30/07/2022 04/08/2022 - 07/08/2022 05/08/2022 - 11/08/2022 12/08/2022 - 21/08/2022 13/08/2022 - 14/08/2022 17/08/2022 - 20/08/2022 19/08/2022 - 21/08/2022 25/08/2022 - 27/08/2022 25/08/2022 - 28/08/2022 27/08/2022

North Sea Jazz Festival Over het IJ Festival The Black MotoCross The Four Days Marches Tilburgse Kermis funfair Rotterdam Unlimited Haarlem Culinair Amsterdam Pride Grachtenfestival Paradigm festival Balloon Fiesta Barneveld Lowlands Jazz in de Gracht 't Preuvenemint Gondelvaarts Giethoorn

Rotterdam Amsterdam Lichtenvoorde Nijmegen Tilburg Rotterdam Haarlem Amsterdam Amsterdam Groningen Berneveld Biddinghuizen The Hangue Maastricht Giethoorn 33

(Beer) Yoga Text: Tim Hut I play volleyball, and this academic year I played in gents 5 of Harambee. During our team weekend I organised a (beer) yoga session. Since it was quite successful and summer holiday spirit in mind I would like to share the routine with you.

[I mainly used one video from YouTube, although it is a giant add, 2 if you’re Dutch I recommend you watch it as it is quite funny] Before we start since it is beer yoga, you need to find yourself a beer or if you’re like me and don’t drink alcohol any canned or bottled drink will do.

[I will continue this text with the assumption you have beer] Now that you have found yourself a beer, it is very important 2 you do NOT open it yet. You will be instructed later when you do open it.

PART 1 1. We start by sitting cross-legged, with your beer closed in front of you.

Take a moment to reflect on how you’re sitting, sit up straight and make your back long. With each breath let you sitting bones get heavier and let your breath 4get slower.

2. Take deep breaths, 4 seconds in, 6 seconds out.

Bring attentions to your thoughts, what thought come to mind? You probably have many thoughts but that’s OK, but DO NOT think about beer.

3. If did think about beer, you can pick-up your still closed beer. If you didn’t think about beer yet, you can still pick up your beer.

4. While you close your eyes for a few moments. [since you can’t read and close your eyes ad the same time, I advise you to read the following passage first] Feel how your can or bottle feels, do you recognize the shape. Measure the temperature, would you like to drink it at this temperature,

34

if not that is your own fault.

Before you open your beer think about what sound it will make.

5. While your eyes are (still) closed, open your beer. But do NOT drink yet.

6. First you’re now going to smell your beer What do you think of the smell, do you associate the smell with the type of beer you’re holding?

7. Take your beer in front of your hear and we now can open the session by saying ‘cheers’ 3 times slowly Cheeeeeeeeeeeeeeeeeeeer s, Cheeeeeeeeeeeeeeeeeeeer s, Cheeeeeeeeeeeeeeeeeeeers 8. Now take one sip from your beer.

Did you taste well enough?

9. Take another sip, but take it slowly and feel the drink flow through your body.

Did the taste match the scent, did it match your expectation?

3 10. Take another sip, once again slowly, and place the beer back on the ground.

PART 2 1. Lay down flat.

Let the first few sips take effect.

How and what do you feel? Do you feel the temperature and do you smell the scent of the beer?

2. While still laying down stretch your arms above your head.

You are now a bottle of beer and slowly you feel relaxation take over your body.

3. You can return your arms next to you and take deep breaths With each breath outwards you feel yourself getting more relaxed. And you fall asleep… … eventually you wake up from the noise of birds.

4. [to set the scene make some bird noises] 5. Stretch yourself, bring your arms towards your knees, while you bend your knees a bit and lift your back and legs from the ground making you balance of your bottoms.

You wake up in a hammock, on a tropical island. Around you, you see

birds of paradise and palm trees.

6. While still balancing on your bottoms, cross your lower legs and then keep changing with leg is on top.

7. Return back to sitting crosslegged.

8. Move your chest a few times back and forth, with each breath in you make your back concave and with each breath out you make your back convex.

Keep your hands on your knees and rotation your shoulders with each movement.

9. Repeat the previous step but now with your arm in the air in a L shape. With each breath in move your arms next to your head and each breath out move your arms in front of you.

10. After a few times when your arms are next to your head rotate your chest a few times from left and right.

11. Return to your initial position still sitting down cross-legged, roll onto your knees, pick up your beer with both hands and take a sip op your beer in the fallen beach umbrella; • Your body is in a L shape (knees and lower leg on the ground), bent your back backwards, the take a sip of your beer.

12. Take another sip in the fallen beach umbrella 4 13. Place down your beer, put your hand on the ground, lift your knees of the ground and straighten your legs such that only your hands and toes touch the ground, bent your knees a few times one at the time.

14. Take small steps towards your hands and stand up and pick up your beer when standing up.

15. Roll your feet one at the time from ankle to your toes and bent the corresponding knee.

You decide to explore the island…

16. While continuing the previous step, take a sip of your beer … and you walk towards the sea.

When you arrive at the sea you take your feet through the water 17. Stand on one leg and with the other leg your make a circular

movement and then change on which leg you’re standing.

The water you’re standing in feels nice so you decide to take a dive.

18. Place your beer back on the ground, stand on both feet do your arms in the air as if your about to take a dive, bent downward and then return back upwards while moving your arms as if you’re doing breaststrokes.

Do this also a few times.

When you return back to the beach you feel the sun in your face 19. Pick up your beer, and again roll your feet one at the time from ankle to your toes and bent the corresponding knee.

You feel in this warmth like a bird of paradise 20. Stand on both feel, do your arms in the air, cross your arms and bent it in a L shape. Bent your knees and drink your beer while your arms are still crossed. Do this again with the beer in your other hand. \t Video paused at 10:45 Source; Kantoor & Loods Gebrouwen door vrouwen (2020), BIERYOGA - Citrus Paradisi lancering [video], https://youtu.be/J1UTMLg_ZRc

Your Story Text: Timon Veurink My first Rubik’s cube competition in two years On Sunday the 17th of April, I had my first Rubik’s cube competition in a about two years, Dutch Spring 2022. During the competition I competed in solving the regular 3x3 Rubik’s cube, but also the 2x2, pyraminx and skewb. A wild simplification of what the last two puzzles are is a Rubik’s pyramid and a Rubik’s cube where instead of the sides, you move the centers. I was quite rusty in pretty much everything because I didn’t practice much during the pandemic and what I did practice was not on the program. But I also didn’t really go there because I wanted to be competitive, I just wanted to see my friends again because we would see each other once every 1 or 2 months and then we just didn’t for two years. I also loved how you could divide the competitors you knew into 2 very distinct groups. 1 group that, just like me, didn’t train much during Covid, and the other group that has trained so incredibly much and just set some amazing times there. There pretty much was

no in between. For Rubik’s cube people that are interested, these were my best results:

mend it to anyone that genuinely enjoys solving Rubik’s cubes, or enjoys watching others do it very fast.

During competitions I also like to do small challenges with others, like having someone be blindfolded with the cube and someone else just telling what moves that person needs to do, or when you are in a duo you can solve 2 Rubik’s cubes at the same time but after every step you continue with the cube of the other person. This is called a factory solve: when you’re in a big group you can do this with many cubes and things tend to be quite chaotic, which is amazing. Especially when you get better at it, because then you’ll be turning your cube while looking at the cube someone else is turning, so you can see what to do next.

After the competition we all went to have dinner together before heading back home. All and all, I really think that Rubik’s cube competitions are an experience unlike any other and I would highly recom-

35

36