First Sabbatical

My offices during the sabbatical. I had an office to myself at HPI (left); I shared an office with Matthias’ PhD students Arnab and Sebastian, who used to be my MSc thesis student, at TU Berlin (middle – photo credit goes to Sebastian here); at CWI, I was squatting in Hannes’ office (right). Sorry for the low image quality on the blogger platform.

Previous semester (August 2023 – December 2023) I was on sabbatical. This means that I had no teaching and (almost no) administrative duties at the university.

This is a practical and personal, not a technical, account of my sabbatical written for the general audience. If you are interested in what I did scientifically during my sabbatical, there is a bit of it here, but not much. I am happy to talk about that separately, and I hope at least a subset of those works will get published eventually.   

 

At ITU, in theory, you can take a one-semester sabbatical after 6 consecutive semesters of teaching or one-year sabbatical after 6 consecutive years of teaching.

Late 2020 (almost three years after I joined ITU), I acquired my first research grant from Independent Research Fund Denmark. It was a combination of a starting grant, Sapere Aude, and a grant targeting junior female faculty, Inge Lehmann[1]. In my Inge Lehmann application, I put some budget for doing research visits abroad since one of the things the call emphasized was the personal development of the applicant.

As an academic, the idea of “doing a sabbatical eventually” was of course in my mind, but I thought it would happen sometime in the not-so-near future. At the time I acquired the grant, I was still relatively new at ITU, this would be the first time I would get to hire my own PhD students. Also, I still had a temporary residence permit and didn’t want to complicate my residence rights in Denmark by leaving the country for a longer duration with a non-EU passport.

Thus[2], I wasn’t the one who asked for my sabbatical, it was my department head Peter Sestoft. During our yearly one-on-one in 2021, he suggested that a one-semester sabbatical would be a good use of my travel money from Inge Lehmann grant. His suggestion made sense to me as well. So, it was decided.

Due to the teaching needs at the university and my own need to first form my own group with the acquired grants, the sabbatical was scheduled for Fall 2023.

 

I have seen people doing different kinds of sabbaticals. The more traditional kind is when the person goes to either another academic institution or a company to spark new ideas, start new collaborations ... On the other hand, some stay where they are and spend more time doing research with the absence of teaching and administrative duties, some use the time to write a book or found a startup, some just rest, some utilize it as an extended paternity leave, and some do a combination of all these things. All are legitimate options in my opinion. The choice should be up to what makes sense for you at that point in your career and life.

In addition to the obvious goals like exchange ideas and start new collaborations, I aimed at the following during my sabbatical: (1) minimize bureaucracy à no new residence permits or visas – you have dealt with enough of those in the last decade, (2) get to know different research groups better à visit different places on the way, (3) introduce your team’s work to other people à give as many talks as possible, and (4) remember that you don’t function well in not-crowded cities and your mental health is more important à prioritize work, but if you can, pick bigger cities for longer stays.

In turn, I decided to do a very mobile sabbatical. I would first stay in Berlin for ~2.5 months splitting my time between Data Engineering Systems group at Hasso-Plattner Institute, hosted by Tilmann Rabl, and DAMS lab at TU Berlin, hosted by Matthias Böhm. Then, I would have a 2-week stay in Amsterdam at the Database Architectures group at CWI, hosted by Peter Boncz. Finally, I would tour Switzerland for 2 weeks giving talks at University of Fribourg (host: Alberto Lerner), EPFL (host: my academic mother), and ETH (host: Ana Klimovic).

While in Germany and The Netherlands, I also took the time to give talks at other places either using my own connections (Volker Markl at TU Berlin, Zsolt István and Carsten Binnig at TU Darmstadt, Martin Hentschel at Snowflake-Berlin, Sebastian Schelter at University of Amsterdam, and at TU Munich for the occasion of Lukas Vogel’s PhD defense) or with the help of my hosts (Matthias invited me to the BIFOLD Summer School, Tilmann helped me to get invited to the HPI Retreat, and Peter put me in contact with Databricks in Amsterdam). The full talk itinerary and the talk itself can be found here.

 

While this plan satisfied all my goals, nothing in life comes without trade-offs. The main drawback of doing such a mobile sabbatical is that it becomes more challenging to focus on one project where you can progress faster and dig deeper. Furthermore, visiting several places in such a short time while other work duties go on in the background can be exhausting both physically and mentally. Some days, I felt very tired or couldn’t sleep well because too much was going on in my head. On such days, I questioned my choice of splitting my limited time across many places. In the end, I don’t regret the sabbatical plan I had, but I would like to be honest about this trade-off.

 

Some people assume that sabbatical means you are completely off your regular job and other work duties, and for some this may indeed be the case, but not for everyone. At least, I had to do other work simultaneously with all these visits.

First, I kept talking to my students regularly online during my sabbatical. For me this is important, especially since the PhD duration is only 3 years in Denmark, and I don’t regret these meetings.

Second, even though I was off teaching and administrative duties for the fall semester, I still had to deal with the administrative stuff related to my course in the spring semester in addition to paying attention to the open faculty call for our group at ITU. While this wasn’t a lot of work and I didn’t mind doing it, it does cause some interruptions.

Finally, I had a lot of academic service work. In retrospect, I probably shouldn’t have taken on that much. I still struggle with finding the right balance with respect to academic service. I enjoy doing this type of work and find it fulfilling and educational; the amount tends to be the issue, not the work itself.

As a result, during my first month in Berlin, I was working six days a week and could take only Sundays off, and my email load wasn’t less than what it is during a regular semester.

 

Let’s talk about the individual visits now; first, focusing on the work, then, on practical matters (e.g., insurance, accommodation) and overall wellbeing. 

Berlin

I worked with Tilmann and Matthias before on different occasions. I knew that they would be open to collaborating with me and there could be synergies across the research that we do. Given the shorter-visits nature of my sabbatical, it made sense to reach out to them first (late 2022) to kickstart new collaborations/projects more smoothly.

The way we approached the collaboration was different at the two places.

Tilmann gave me time to talk to his students the first couple of weeks of my stay in Berlin. Then, I told him the project I find the most relevant given my research background and interests, and we started collaborating on that one. I have more of a secondary supervisor role in this collaboration. Marcel Weisgut, one of Tilmann’s PhD students, drives the work. The project is on analyzing different cache-coherent interconnects and allows me to get back to my transaction processing roots, which I really enjoy.

With Matthias, I tried something riskier. I haven’t been coding properly since I left IBM. I told him that I would be open to getting back to coding. But it had to be in c or cpp (so no SystemDS for me). We discussed different project visions he had, and I picked one. In this setting, Matthias has been like my advisor, and he is a really nice one. (Not sure if I have been a good student, though.) I am also involved in one of the BSc thesis projects he has. Both topics here are out of my comfort zone as they are more into the inner workings of machine learning. I work on machine learning systems now, but my focus is more on the systems and hardware side. I have been learning the machine learning internals very slowly and only at a necessary level in the process. As for coding, I really enjoyed getting back to it, but given everything else I was doing in parallel, I could only focus on it one day a week when I was in Berlin, so the progress has been slow.

Tilmann, Matthias, and I also discussed ideas for a joint project that we can kickstart in the near future. This may or may not materialize, but I am optimistic and excited.

 

Amsterdam

In contrast to my history with my Berlin hosts, I have never had a chance to work with anyone from CWI[3]. I have learned a lot from the work done by the Database Architectures group at CWI, especially early in my PhD when I was trying to understand database systems. They knew me from conferences. For the remaining part of my sabbatical, I wanted to visit them to get to know the group and the place better and see if there could be avenues for collaboration in the future. So, I reached out to Peter (during SIGMOD in June 2023), and he was very welcoming.

I was aware that I wouldn’t have so much time for this visit. After Berlin, I had roughly a month left in my sabbatical before Christmas holidays. I knew I had to put Switzerland on my path as well, but we will get to that later. Thus, I could only have about two weeks for the CWI visit.

Two weeks is too short to start anything from scratch. In addition, at that point in my sabbatical, my head was quite tired due to splitting across different projects and locations. I unfortunately didn’t have the headspace and energy to jump into something brand new while I was still in Amsterdam.

Instead, I decided to use my time to develop a few project ideas I had that involves using DuckDB; related to emerging SSD technology, resource management on resource-constrained devices, and data management support for our experiment tracking platform radT. I had very helpful discussions with Peter, Hannes and Mark at DuckDB labs, and Till from MotherDuck on these ideas. With the start of 2024, I managed to take the baby steps on a couple of these projects, we will see how things evolve.

 

Switzerland

I did my PhD in Switzerland. People have been inviting me to Switzerland since I moved back to Europe. While there are a lot of people whom I consider to be family in Switzerland, I tend to avoid visiting the place and prefer catching up with the people at conferences elsewhere instead. My complicated relationship with Switzerland surfaces here and there in this blog, most recently in this post. I won’t delve into it further here. During my sabbatical, it made sense to stop the avoidance and carve time to visit Switzerland.

I allocated two weeks for this visit as well, but this time I didn’t want to stay at one location.

I collaborated with Alberto Lerner from eXascale InfoLab at University of Fribourg, and several others, recently that led to a CIDR 2023 paper. Alberto asked me to visit them many times before. So, I reached out to him to make that happen finally. By the end of my visit, he almost convinced me to go there for my next sabbatical to learn FPGA programming.

Then, the roots of my academic family are at EPFL. So, I reached out to my academic mother and Dimitra to visit EPFL. They kindly aligned the DIAS end-of-year raclette party with my visit. That party is one of the things I miss from my PhD years, so I really appreciated this. It was a lovely reunion.

Finally, two of my PhD students (Ties Robroek and Ehsan Yousefzadeh-Asl-Miandoab) did their research stay abroad (a mandatory part of PhD at ITU) at ETH (hosted by Ana Klimovic) and University of Basel (hosted by Florina Ciorba), respectively. While we unfortunately couldn’t find a suitable date with Florina, we were able to arrange a visit with Ana. It was my first time visiting the systems group at ETH. I especially loved exchanging info and experiences with everyone there working on a variety of systems topics.

During this leg of the sabbatical, I also had the chance to see many people that I haven’t seen in such a long time from academic family to family friends, and I am grateful to my academic sister Danica Porobic for being my unofficial host in Switzerland.

 

All the interactions I had during these visits were worthwhile on their own even if in the end nothing comes out of the projects I got involved in or made plans for during this sabbatical. I am very grateful to my hosts, all the PhD students, and other team members for taking the time to talk to me.

 

Practical stuff

Accommodation. Most of my travel and accommodation expenses during the sabbatical were covered by my own funding. However, my hosts also helped. Tilmann asked HPI to cover my train tickets to/from Berlin and gave me really good tips for accommodation, which helped me to find a very good option with a reasonable price in Berlin (I booked six months in advance). Peter helped me to get a room at CWI guesthouse, which reduced my costs substantially in Amsterdam. In general, it is good to reach out to people early on and ask them for tips for these practical matters.

Thanks to my funding, I was also able to keep my apartment in Copenhagen as is and was back in Copenhagen a couple of times in between visits. It was nice to be back home for a bit.

Visas. Since I on purpose arranged my sabbatical in a way that avoids visa applications, I didn’t have to worry about this, but acting early would also be important on this matter. On the other hand, keeping my stays relatively short at different places was partially motivated by this goal. With my Danish resident card, I am safe traveling up to 90 days abroad in Schengen region, but not more. Technically, no one checks or stamps your passport when you are within the Schengen region, but this isn’t something I would abuse, especially carrying the kind of passport I carry.

Health insurance. The health insurance I have thanks to my job becomes invalid for sabbaticals since work trips that are longer than 28 days are no longer covered. If you are an EU citizen, you may still be covered through your Blue Card, but I am not entirely sure, since I am not eligible for this card as a non-EU citizen in Denmark, so I didn’t investigate it further. Therefore, I had to find another solution for my health insurance.

Following up on the suggestions of a few colleagues, I decided to check if I can get a Mastercard Gold, which provides health and travel insurance for trips up to some length in Europe, which fit well for my sabbatical case. And since my Danish bank likes me (the feeling isn’t mutual), they agreed to give me a Mastercard Gold for a cheap price. Now, I have three cards: one parliament blue, one smoky gray, and one gold. I wish I had pink, red, and purple instead.

Luckily, I didn’t have to use the gold card for health insurance purposes, but it was the only option I had while paying for the long-term accommodation bill in Berlin. The limits of my other two cards weren’t high enough.

Carrying my stuff. I had to buy two new carry-on-size suitcases. I won’t go into further details on this one unless you ask for it, but in general I spent more time than I expected (and wanted) thinking about suitcases and how to pack them.

Communication. I didn’t have communication issues except for the French-speaking part of Switzerland. I got around in Germany easily with the combination of my English, highly deteriorated German, and native Turkish. In Amsterdam, English was enough, but I made attempts at parsing written Dutch using all the languages I know. In Lausanne, I was impressed by my ability to still remember how to order food in French. It was out of necessity as I didn’t have the option to order things in English. In Fribourg, asking for directions at the university building in English got me nowhere, and I texted Alberto.

Other expenses. I never thought I would say this, but Copenhagen is cheap. I knew it would be cheaper than Switzerland. But it is also cheaper than Berlin, at least in terms of my usual university-lunch-plate and grocery shopping. I didn’t stay in Amsterdam long enough to judge this well, but it felt similar to Copenhagen in terms of such costs.

 

Wellbeing

During my first week in Berlin, one concern a couple of my friends had for me was whether I would feel lonely and down. Their concerns were valid since I have a track record of being slightly depressed whenever I move to a new country till I get used to the place (or in the case of Switzerland, the whole duration). The sabbatical was a substantially different experience, though. I have neither felt lonely nor depressed at any point. I would attribute this mainly to two factors: the social nature of my sabbatical and me being older.

First, my hosts, Tilmann, Matthias, and Peter, were all extremely supportive and inclusive, and their groups immediately adopted me as one of their own. There were also a lot of work-social activities of the good kind, not the draining kind.

The rest of the time, I was going around visiting different places and giving talks. In a way, I didn’t have time to be “down”. I had overall constructive interactions and discussions with people during these visits. There was only one instance where I felt slightly like shit after my talk because of certain attitudes both during and after the talk, but other times were all energizing experiences.

Second, I have known myself for almost 36 years now, and with that knowledge I can better prevent or damage-control negative experiences. My sabbatical goals #1 and #4, as listed above, were there because I was trying to avoid certain things that tend to pull me down. Following those goals, I didn’t need another Western-world approval for my existence at the places I was visiting, and both Berlin and Amsterdam are great cities to be in for longer durations for me. In Berlin, my body felt like she was in her natural habitat. In Amsterdam, I had the same feeling I had when I visited Copenhagen for the first time (for my ITU job interview), which I will call peaceful excitement.

 

On the other hand, my rent-like period got a bit off during my sabbatical and I had trouble sleeping on some nights, especially toward the end. Considering my intense and mobile schedule, this was expected, I guess.

 

Ending with the most important point. When I announced my sabbatical, a friend joked “Is this an excuse to watch Gilmore Girls again?”

I have a tradition of watching Gilmore Girls every time I move to a new place, which means that I watched the whole series 5 times and watched parts of it even more times as I introduced it to other friends. The logic behind this tradition is at a new place, in the beginning, one must deal with a lot of instability without having much to rely on. A show like Gilmore Girls gives me the feeling of stability amid the chaos.

My sabbatical stays were somewhat eligible to put my Gilmore Girls tradition into action. However, shortly before my sabbatical, I started rewatching Gilmore Girls with my dear colleague Veronika Cheplygina. During my sabbatical, it made sense to pause it and resume with her when I get back. Since I believe in flexible traditions, keep the core and adjust the content if you need to, I instead went further back in the nostalgia lane and started to rewatch Buffy the Vampire Slayer. Still watching it and currently at season 6.

 

---

[1] Back when I applied, Inge Lehmann was a new call, and you had to apply together with the starting grant. The year after, they separated these two grant applications, which was a good decision as it gives more options to junior researchers.

[2] I cannot use the word “thus” without thinking of Saltburn anymore.

[3] I worked with Erietta Liarou, who did her PhD at CWI, but I don’t think this counts, since she was a postdoc at EPFL and no longer at CWI when we collaborated. Also, an unrelated note, people used to mix-up Erietta and I at conferences a lot.