Weblog Melissa Wijchers

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#6: Update

Hey all, another month has passed! Time for an update.

For part of the time last month this update is meant literally: if you have looked at the Msc Applied Mathematics page of the TU delft website before this month (and then again this month) you might have noticed that it has changed somewhat. This is because I was asked to update the information on this page and to make the layouts of the different masters at EWI more alike. So over the winter break I wrote a many paged word document containing all the changes and as of somewhere this week, all the changes will have been applied!
For those that have no clue what I’m talking about, its this website:


Not study related: I’ve been having shoulder pains for quite some time now, which mainly occur when doing anything in gymnastics when in handstand (or even push-up) position. It is time to have it checked out at a fysiotherapist. One perk of being at a gymnastics club is that injured members know which fysiotherapists are good. So at 23:00 I registered at one place, the next morning they called me and I had my first appointment the day after. What a service!!
The following weeks were full of exercises and I had my shoulder taped for some pain relief and support.
taped shoulder
On the first day of March, I presented my literature study to my thesis committee. However, 25% of them decided not to show up (yes one whole person 😉 ). I ended up giving the presentation to three people and at the end one went away and I could have my weekly meeting with the remaining two, who are guiding me.
After the literature presentation it was time to focus on finishing the Matlab code. This includes making the programme easy to work with and commenting code where needed. Hopefully real data can then be easily put into the programme and give results which I can work with to improve.

As you might know, I try to do sports 3 times a week and gymnastics is quite a big part of my life next to studying. As I was standing in the elevator at the EEMCS faculty I noticed a poster about a seminar; ‘Data Science and Sports’. This event is organised by Delft Data Science of TU Delft in collaboration with Leiden Centre of Data Science and the Sport Engineering Institute (of TU Delft). For those already in Delft and who are interested in finding out how mathematics is used in sports, this is the poster.

By the way, if you want to experience a fast elevator, try them at EEMCS 😉 Then go to the top floor to get amazing views of Delft and the surrounding area.

#5: Leap day

What a special day today. One that only occurs once in four years and I’d like to take advantage of it to write another blog!

First some facts about leap day:leapday

  • Why leap day? Because the Earth rotates about 365,242375 times a year . A normal year is 365 days, so something has to be done to “catch up” the extra 0,242375 days a year.
  • How do we do this? Every 4th year we add an extra day (the 29th of February), which makes 365,25 days a year. This is fairly close, but is wrong by about 1 day every 100 years.
  • Every 100 years we don’t have a leap year, and that results in 365,24 days per year (1 day less in 100 year = -0,01 days per year). Closer, but still not accurate enough!
  • So another rule says that every 400 years is a leap year again. This gets us 365,2425 days per year (1 day regained every 400 years = 0,0025 days per year), which is close enough to 365,242375 not to matter much.

For the past few months I have been telling you about my thesis within the MRI world. However, the MRI world is very large and there are many different researches going on worldwide. Today I found an article on the TU Delft website about one of them: Researchers are to develop new hybrid PET/MRI system for improved breast cancer diagnostics ( http://www.tudelft.nl/nl/actueel/laatste-nieuws/artikel/detail/onderzoekers-ontwikkelen-nieuw-hybride-petmri-systeem-voor-een-betere-borstkankerdiagnose/).
Even though the TU Delft expertise is focussed on designing, developing and testing the PET modules, it is interesting to read how medical imaging is continously changing and improving for the better!!

During your thesis you also get to expand your knowledge as well as deepen your specialisation knowledge. To get to the point where I am now in my thesis, I had to understand a lot of electro magnetism and other practical elements to get the right mathematical equations. Another thing is having to work with programs you’re unfamiliar with. During the bachelor we learnt how to use Matlab, Maple and a bit of Java. Now it can happen you will learn a new programming language or work with new simulation software. In my case this is COMSOL. Luckily I had some experience with it in my internship!!

A hobby of mine which I’d like to do at the weekends with my dad is geocaching. It is like a real life treasure hunt which adults also enjoy. You find the coordinates on the Geocaching website, then you go out to the place of these coordinates and find a stash. It is done all over the world including Delft. Some also require you to solve some kind of puzzle to find the coordinates, like: https://www.geocaching.com/geocache/GC43P5N_i-love-concrete . Delft definitely has some very hard ones, but what to expect with a university of technology  😛

Some of my stats (we’re still mathematicians here!):

  • Member since  08/05/2004.
  • Find rate: 0.2875 caches/day (now you can guess how many geocaches I have found in total!)
  • Best year: 463 caches in 2015 (with a find rate of 1.2685 caches/day)

Another picture 😀 Of which you might not know whats going on. It’s actually the writing of this blog! Next to something I’m now going to tell about…


Two weeks ago, I was asked to help with a bachelor’s course, Numerical methods 1. Being a student assistant is not new to me, I have done it several times for different studies. However this is a first for Maths students. Another first is that this time being a student assistent means mostly correcting homework assignments. Before I assisted at scheduled ‘lectures’ in which the students work on their exercises and could ask me questions. So yeah, it’s something totally different and grading the first assignment was kind of confronting. Working with 3 other assistants meant for me that I had some questions about when to say something is right or wrong. Having the correct solutions, you still have to see how everyone solves the exercise and most of the times this is not close to precisely the correct solutions. But I’m halfway through now and it’s going okay 🙂 (at least, I think so …. 😛 )


#4: The literature study (distractions?)

The first week of this month was for most students a week off. Many left Delft to go snowboarding or skiing. That meant that the teachers guiding me with my thesis had much free time, so this wasn’t so much of a vacation week for me.

During the day I worked on my thesis, getting the last practical parts straight before I had to focus on the literature study report and presentation.  So for the people reading this and thinking ‘what is she talking about?’: after about 3 months you have to write a report on your progress and present this, the research goals and how you are going to go about doing that. So basically you explain what you are going to do for the remaining time of your thesis. It is a moment for you and your guiding teachers to get on the same level.  The second week of February I worked hard on the report. Up to now I did write parts of what I had done and researched, but that was to summarize everything for myself. There was absolutely no consistency between chapters: one about conventional MRI, one about the set-up of the situation we will get real data from, one about the signal generation and one with some information on regularization and numerical solvers. All far from complete, but working progress.


Ah, something I thought was very nice; in the first week of February, Delft welcomed the new international students who are here for their Bsc/Msc or just a semester abroad. One of my friends is on the ESN (Erasmus student network) Delft board and helped with the activities. I visited her doing this and getting a glimpse of what it is like here for international students.  Some typical Dutch activities were set up: ‘sjoelen’ (shuffleboard), sack racing and many more. They could also taste some Dutch foods like hutspot and stroopwafels.

sjoeltafel   stroopwafels

Ever heard of DDB? If you are a Dutch student in Delft you can probably tell what the abbreviation stands for (De Delftse Bedrijvendagen), an international student in Delft probably recognizes this abbreviation and might know what it is. For all new or aspiring international students, DDB is literally translated as The Delft Companies days.  It is a way for students from Delft to establish contact with companies that are of interest to them for possible internships, graduation research projects and job applications. Last year, over 130 companies participated. Approximately two thirds of all graduating students at the TU visit the career fair!

Besides the two day fair at which some companies also give presentations (hence the name ‘Presentation Days’), there were also application trainings. These are very useful if you’d like the opinions and advice of recruiters on your CV, your motivation letter and your interviews. A photographer was also present these days to take professional photos for your LinkedIn profile or for on your CV. I also had mine taken and will probably share it with you when I receive it (only if I like it myself ofcourse 😉 )

Now I’m left deciding at which companies I’d like an In-house day and which I might like an interview with… That alongside finishing my literature study report and making a presentation 😛


#3: The new years resolution

Hey all,

normally I do not have a new years resolution, because I believe you shouldn’t have to wait for the new year to start achieving a goal. Even though I have not outspoken a resolution this year, I want to do many ‘firsts’: trying out new things.
Today was my first day working in Leiden for my master thesis. It was at the C.J. Gorter center for high-field MRI at the Leiden University Medical Center. I knew the professor there from a previous meeting and one of my friends from Mathematics who has started a phd there after the graduation. First obstacles are the usual ones for any place to work: finding a workspace, getting an account and a badge etc. Getting to know the many new people and remembering the many new names (first day: name in one ear, out the other… except for the people you speak to for more than 1 minute).
It surprised me that there were many students (Msc and phd) from Delft working here. Not just from Mathematics, but also Physics, Electrical Engineering, etc. During an internship last summer the average age at my department of the company was far higher than my 23 years, but here I felt more comfortable the first instant because I’d have more in common with students than people almost double my age.

My project is making some progression. The signal which is to be received has been derived. For now that will be put aside until we receive real data. Also first we have to find a way to reconstruct the image without much of the expensive hardware. To do this, an artificial signal has to be created. It is also convenient to start with an image. When it is put through a forward model to find the signal it can be used to compare it to the reconstructed image. Did you know Matlab actually has a command to have a model of the human head (called Shepp-Logan phantom image)?



At the end of last year I decided that I wanted to become a blood donor, but to be able to be one you have to undergo some blood tests and you get asked many many questions about your health. The blood tests would take 4 weeks to process and you’ll ONLY hear if something is wrong. Last week I received a card to come to the location and donate, so luckily everything is okay with my health! Taking the four tubes for tests was the first time ever for me to have my blood drawn and was such a strange experience, so I’m curious to how it will be to have lost a whole liter of blood. (YES, another FIRST!) Everyone asks me why I wanted to donate, my question to them: why not? It is something that was asked to people on the street and strangely many of them could not answer this question (see video, it is in Dutch however). You would want someone’s blood if you are lying hurt in the hospital in need for blood, why not do the same for others?

**UPDATE** I have now donated blood. It feels good, doing a good thing. They say you might feel faint after donating, but I felt fine physically. I was only scared of a big bruise because they fiddled around with the needle as the machine didn’t receive the blood as quickly as it needed… That also turned out fine! Now we wait and hope we saved someone’s life or helped with some progress in research..

#2: The start of my thesis project

Hey everyone! It has been a month already since I introduced myself. November was very eventful for me, so let me tell you some of it..

At the end of October I had to decide which thesis project I wanted to do. I had a few options, including staying at TNO where I did my internship but with a very different project or going back to EEMCS. I decided to do my thesis project at the numerical analysis group at EEMCS but working together with Leiden University Medical Center (LUMC). To be more precise, the research group revolving around magnetic resonance imaging (MRI). In short I have to research whether it is possible to get a reasonable image from a simplified MR imager. If a simple MR imager could be built, it can be used in third world countries as it is most probably less expensive and lighter and smaller.

Right now I have had about five weeks of literature study. To be able to find a way to imitate such an imager in a simpler way, I have to have a sufficient understanding of how MRI works. After the first week, my supervisors and I travelled to Leiden to visit our project contact there to discuss the start up of this project. I got to see a real life MR imager for the first time! ( Yes I’m one of those people that has never been seriously injured even though I do risk-prone sports.) He also showed us the model I will be working with, which is at this moment just a ring shaped magnet consisting of smaller magnets. To visualise the size: just one hand would fit in it, but with every experiment you have to start small.


The TU Delft has a Sports & Culture center, at which you can do sports, dance, painting, singing, photography etc.. Basically name something and you will probably be able to do it here! So one evening last month the Culture center had a try-out night. This evening you could join any class and see if you like it (or not..). After 5 years in Delft I decided to go, mostly for fun, but also to see whether ballet would improve my body awareness with gymnastics. I can conclude that this will probably not be the case for me 😛 I also tried Classical singing (because a friend had dragged me along, even though I only sing under the shower…) and hip hop dancing. It was a really fun night and met many international students. They even invited me along to some party they were going to go to afterwards!


Last but not least: I had a student gymnastics competition! I still think competing is not my thing. I love to do new tricks, but I’m not the most graceful person on the planet XD. The new elements I wanted to perform at the competition worked out well, so it was a good day for me even though I finished 14th out of 20.

As I’m not sure I will write again before the new year, I wish everyone a very merry Christmas and a happy and healthy new year! Oh and if you are in Delft, the city center is really pretty with christmas lights and there is a large tree on the Markt square


#1: The introduction

Hello everyone! Welcome to my blog. I’d like to start of with a random thought: starting a new weblog, you are welcomed with a first post: ‘This is your first post. Edit or delete it, then start blogging!’. The automatic title was ‘Hello World’ and it made me think about my first course in programming. Apparently it is the start of everything!

Now let me introduce myself: I’m Melissa, 23 years young and born in the Netherlands. During ages 11-15 years old, I’ve lived in the United Kingdom and afterwards my family and I went back to the Netherlands. On my 18th birthday I was at the freshmen weekend of the study association Christiaan Hugyens, about to start my Bachelor degree in Applied Mathematics at Delft University of Technology.

Right now I’m in my second year of my master Applied Mathematics, the specialisation Computational Science and Engineering (CSE). This year consists of an internship and a thesis project. In October I completed my 3-month internship at TNO and now I’ve been busy with my master thesis for a few weeks.

In my free time I love to do sports. The sport I do right now is gymnastics, which I do at D.S.T. Pegasus with other students. I’ve also done a few other sports since I moved to Delft including rowing and handball.

So that’s me. The coming year I’ll be posting blogs about many things: this master, my thesis, the study association’s activities, Delft, and some other things I do when I’m not studying. I hope you will enjoy reading my blogs and if you have any questions feel free to comment below.


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