Workshop on Counting and Sampling, 2021 edition

Just like last year, the International Workshop on Counting and Sampling was held online, in conjunction with the SAT conference. Just like last year, I was honoured to be invited to submit an extended abstract to this workshop.

We decided to submit an update of Jeroen’s work on caching for model counters, based on his master thesis work. It was accepted, so last week Jeroen presented our work.

Zoom screenshot of Jeroen's title slide, which reads: "Caching in Model Counters: A Journey through Space and Time", by Jeroen Rook, Anna Latour, Holger Hoos and Siegfried Nijssen.

While I was naturally happy to see our work presented, I also very much enjoyed the rest of the program. It has been a while since I’ve seen so many interesting talks in a row. I particularly liked the contributions from Tuukka Korhonen and Lucas Bang.

Jeroen’s slides can be found here, and a recording of his presentation is also available online.

Thanks to the organisers! I am looking forward to attending next year’s edition!

Defence time for Jeroen

I am very proud of my student Jeroen Rook, who defended his Master thesis today! The title of his presentation was: Caching in Model Counters: A Journey through Space and Time. With a very general audience, Jeroen had his work cut out for him to explain not only his work, but also the basics of propositional model counting.

After his presentation, Jeroen defended his work to me and his other advisers, Prof. Dr. Holger Hoos and Prof. Dr. Siegfried Nijssen. He handled our questions as well as those from the audience quite well, impressing us with his knowledge of the #P complexity class.

A preliminary version of this work was accepted at the  Workshop on Counting and Sampling 2021.

Daniël’s graduation

I feel like I just levelled-up as a scientist! Yesterday, the wonderful Daniël Fokkinga graduated with a very nice grade!

He contacted me in 2018, because he was interested in working on a project that I had proposed to help me integrate in the ADA research group, after they had ‘adopted’ me as a PhD student. The plan was to apply the paradigm of Programming by Optimisation (PbO) to an algorithm that my co-authors and I had developed for solving Stochastic Constraint Optimisation problems. Marie Anastacio would be my co-supervisor for this project, which was ultimately overseen by Holger Hoos and Siegfried Nijssen. Thus, I would have an opportunity to get acquainted with PbO, and with Marie and Holger, while at the same time helping a student graduate and do some cool, new science.

And that’s exactly what Daniël did! His work was accepted at the Data Science meets Optimisation workshop held in conjunction with IJCAI 2019 in Macau, and I had the pleasure of seeing him present his work there.

After a successful presentation and defence of his work in November 2019, he had completed all the work that he needed to get his MSc degree in Computer Science. Yesterday, we attended his graduation ceremony, after which we had drinks in the pub opposite of the Academic building in Leiden: Barrera.

I’m very proud of Daniël (and of myself) for achieving this milestone, and hope his next job will bring him a lot of fulfilment and adventure!

Daniël defends his work

Yesterday was a very special day: Daniël Fokkinga, the master student who I have been supervising together with Marie Anastacio, Holger Hoos and Siegfried Nijssen, presented and defended his master thesis!

It is wild to see this happening only a few years after I defended mine. It feels like it was just such a short time ago that I was in his shoes, and yet I’m at the other side of this interaction now, prepping difficult questions for him to answer.

I was very happy to see that he brought a lot of friends and family, and it was lovely to meet them. Meeting Daniël’s parents and brother made me feel quite special, because he’s been such an important person in my work life for over a year, working with him on an interesting line of research. It was nice to have someone at the institute to talk to about my own research, and very gratifying to see him do so well at his presentation. It made me feel special that I got to share that with the actual important people in his life 🙂

Congratulations to Daniël for achieving this milestone!

BNAIC/Benelearn 2019

Last week I attended the Benelux Conference on Artificial Intelligence and Machine Learning (BNAIC) for the first time. This year, it was held in Brussels, in my beloved Belgium.

This year’s edition was framed around AI Synergies: business meets academics. This was very well reflected in the excellent collection of demonstrations, where we learned about self-driving wheelchairs and puzzle-solving technology.

My contribution to this conference was an extended abstract of this year’s IJCAI publication, in which we introduced a new propagation algorithm for stochastic constraints, implemented in the OscaR solver.

My presentation was scheduled in the very first session on the very first day. I was afraid that nobody would turn up, but luckily roughly forty people did. True, a lot of them were my amazing colleagues from the AIA group at UC Louvain, and a few of my (former) colleagues from LIACS in Leiden, but there were also a lot of very unfamiliar faces there.

Then, in my presentation, I used the example of a viral marketing campaign for chocolate, by means of ‘seeding’ certain people in a social network by giving them a free sample of the chocolate, and relying on them to promote the product to other people through word-of-mouth.

As a reward for the people who showed up at this early hour, I handed out Belgian chocolates to my audience. I hope they appreciated the joke 🙂

Impressions of IJCAI 2019

This summer I got to attend the International Joint Conference on Artificial Intelligence (IJCAI) for the third year in a row!

First impressions of Macau

Since I’m spending this summer at UofT, I had to travel for just under 30 hours to get from Toronto to Macau, where I shared an airbnb with my colleague Marie and our master student Daniël. I arrived around midnight, in a 30-degree humid heat, with a 12-hour jet lag and still a bit flustered by the protests I encountered at Hong Kong airport. While the airbnb wasn’t particularly fancy (we are on a budget, after all) I was grateful for the AC, the cool shower, and the opportunity to check the wheels of my suitcase for crushed cockroach.

After a short night on my part, we walked to the west entrance of The Venetian: the hotel/casino that would host the conference. The Venetian was… an experience. During one of the breaks, I sneaked upstairs to check out the replica of Venice they built on the third floor. It was… an experience. All the stores and all the people made me dizzy, and the building seemed to have been designed by M.C. Escher: no matter where I went, I always ended up at the shops or the casino.

The canals and shops of Venice inside the Venetian in Macau.

I quickly learned that it was better to stay outside. The outside temperature never went below 30 °C, and with the high humidity, hot sun and occasional thunderstorm, most of us were soaked within a minute of leaving the venue. Therefore, we tended to stay inside, checking out the food courts of the adjacent hotels during our lunch breaks.

All the kitsch and replicas, as well as the mimes in the Parisian and the singing gondoliers in the Venetian created such a surreal feeling of dreaming in me. A very weird place to go for doing your job as a computer scientist, indeed.

The Data Mining meets Optimisation workshop

The ADA research group sent a delegation of four researchers to IJCAI this year. Aside from Marie, Daniël and me, our professor Holger Hoos also came to Macau, just in time for the Data Mining meets Optimisation workshop at which our group presented no less than two papers!

After Daniël presented his paper (I am so proud!) and Marie presented hers (she has so much authority!) in the morning, Holger gave an invited talk about Cooperative competition: A new way of solving challenging problems in AI and beyond, giving us all food for thought for the reception afterwards. Of course, our mascotte, little Ada, was there to support us. Later, she came with us for a celebratory drink, showing her support for CLAIRE, too.

Little Ada Lovelace, our Lego mother of Computing, supporting the CLAIRE initiative. See how she resembles Leiden University’s Minerva?

My IJCAI highlights

One of my main highlights was getting to see professor Adnan Darwiche talk about his work. Throughout my short career as a PhD student, I kept returning to his work. In particular I have been building on his ideas of knowledge compilation: clever ways of representing solutions to problems that allow us to reason about those problems in a very fast manner. Darwiche inspires me as someone who, even at this stage of his career, still publishes papers all by himself. He is a great example to me, and it was incredible to get the opportunity to attend his talk on Reasoning about the behaviour of AI systems.

I was also very excited to attend talks by so many of the amazing fellow PhD students and postdocs I’ve met over the years: dr. Sebastijan Dumančić presented two papers in the Understanding Intelligence and Human-level AI in the New Machine Learning Era track and received an honorable mention for the EurAI Distinguished Dissertation Award 2018, and Alberto Camacho presented so many papers on Linear Temporal Logic (LTL) in both workshops and main conference, that I frankly lost count. Aside from these presentations, I also attended those of dr. Emir Demirović, Mohit Kumar, prof. dr. Lars Kotthoff and many, many more. All in all, there were so many presentations by these research friends, that they even overlapped, and I had to choose! (And no, I won’t tell you whose talks I did not get to attend 😉 )

This year was the second time that I attended the Women’s Lunch. I don’t know if this was intentional or not, but I got the impression that the organisers made a real effort to include the younger generation of female AI researchers in the community. Almost all of the senior women present at the lunch approached me to introduce themselves or to just have a chat.

Finally, of course, there was my own presentation. Unfortunately, I was awarded a time slot at the end of a session at the end of the day at the end of the conference, so the audience wasn’t as alert and attentive as I would’ve hoped. Despite this, they asked some interesting questions and laughed at my jokes, so that was good.

When I think back at how much effort went into this paper, it is hard to believe. I might actually write a blog post about it one day, for I reckon it could be interesting for someone outside academia to get a glimpse of what goes into publishing a bit of research at a conference. For now, the most important thing to say is that I feel very, very fortunate to have worked on this project with two of the most dedicated, smartest, kindest researchers I know: dr. Behrouz Babaki and prof. dr. Siegfried Nijssen.

Time for some R&R

Occasionally, we have a little time for being a tourist. I went to the northern part of Macau on two different evenings, sampling the local food. On another evening we went to visit the fake Eiffel Tower and looked out over all the lights in the city.

Looking out over Old Macau (and in particular the Ruins of St. Paul’s) from the Monte do Forto.

On our last day we went to Macau tower for lunch. It has a rotating restaurant and we very much enjoyed the view, both of the city and of the people bungee-jumping off the tower!

View from Macau Tower.

After lunch we went to see the Guia Lighthouse and Lou Lim Loc garden. Unfortunately all in the pouring rain, but we still enjoyed the views and the turtles. We bought some bubble tea and took a taxi back to the hotel. From there, I took a bus to the ferry to Hong Kong, to continue my travels there.