Category Archives: Current Events

Invited Talks at the Simons Institute

This spring I have been very fortunate to have been invited to give to talks at the various different seminars run by the Simons Institute in California.

The first talk on solving MaxSAT was given on the 13th of April together with Matti Järvisalo. The talk was a part of the Beyond Satisfiability seminar, a recording of it can be found here.

The second talk will be on MaxSAT preprocessing on May 5th as a part of the Theoretical Foundation of SAT/SMT solving workshop. More information can be found here. As the talk is online. I invite anyone who is interested to attend. I am sure the talks will be interesting, personally I am looking forward to hearing about SAT and QBF preprocessing form Benjamin and Martina.

I would like to thank the organisers of the various seminars of the Simons Institute for considering me as a speaker in their events.

My Thesis won an Award

I am happy to let you know that my Thesis: Solving Optimization Problems via Maximum Satisfiability: Encodings and Re-Encodings was awarded the international ACP Doctoral Thesis Award by the Association of Constraint Programming. I will be receiving the award and giving a presentation on my thesis on the 11.9 at the CP 2020 conference. The conference is virtual and free to attend, I hope to see you all there.

Im an honoured for receiving the price and want to thank the ACP for the recognition.
My presentation can be found at: at google drive.

A news article with more info can be found at: https://www.helsinki.fi/en/news/data-science-news/international-dissertation-award-to-berg

MaxSAT tutorial at ECAI 2020

Tomorrow (4.9.2020 at 14:00 Helsinki Timezone) I will be giving a tutorial on MaxSAT at the ECAI 2020 conference together with Matti Järvisalo and Ruben Martins. The event is virtual and attendance is free, so any interested people should attend.

I am looking forward to the (new) experience of giving a tutorial, I am happy with the material and am sure we will be able to tech people about modern MaxSAT in an affective way.

Best Paper award at SAT 2020

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I am happy to let you know that my paper titled Abstract Cores in Implicit Hitting set MaxSat solving has been awarded a best paper award at the 2020 SAT conference. The paper reports on work that was started during my visit to Toronto in 2019. We propose a technique that seeks to address the inherent drawback in the so called implicit hitting set approach to MaxSAT solving, one of the most successful approaches to solving MaxSAT instances corresponding to real world applications. Abstract cores seek to reduce the number of cores that the algorithm needs to extract before terminating without increasing the complexity of the core extraction steps too much. The instantiation of this idea in the MaxHS solver was one of the best performing approaches in the 2020 MaxSAT Evaluation.

I would like to thank the conference organizers for the recognition and for putting together an event that, considering the current circumstances, was probably the best possible way of organizing SAT 2020. I would also like to thank my co-authors, especially Prof. Fahiem Bacchus for his efforts in the implementation and getting the experimental results.

New paper accepted

I am happy to inform you that my paper “Abstract Cores in Implicit Hitting Set MaxSat Solving” has been accepted to the SAT 2020 conference.

The paper proposes an improvement to the so called Implicit Hitting Set-based approach to exact MaxSAT solving. The paper summarises the work we did with professor Fahiem Bacchus and MSc, Alex Poole during my visit to Toronto last year. I am exited by the paper. Thanks to both of my co-authors!

I will add the paper to these pages once the camera ready version has been submitted.

 

New presentation

I gave a talk at the Logic Seminar of the department of Mathematics and Statistics today. I talked about the algorithmic benefits of using propositional logic when solving optimisation and decision problems. As a concrete example, I used the Bounded Treewidth Bayesian Network Structure Learning Problem that we worked on a few years ago. Please find my slides: here.

Thank you to the logic group for having me, it was both interesting and fun.

Excellent performance in the MaxSAT Evaluation

The MaxSAT Evaluation is an annual event meant to evaluate the state of the art in MaxSAT solving technology. The evaluation has two tracks: the complete track, where the goal is to find the provably optimal solution as fast as possible and the incomplete track where the goal is to find a solution which is as good as possible within a limited time.

This year we submitted a solver called Loandra to the incomplete track of the competition. Loandra implements core boosted linear search, an idea described in this paper that I worked on during my visit to Melbourne last fall. The results of the Evaluations were presented yesterday at the SAT conference, I’ve only seen a summary but I am happy to say that Loandra performed very well, achieving the highest score on the unweighted 300s track and the second to highest on the weighted 300s track. Overall a very nice result, I am very pleased.

I’d like to thank the organizers of the MaxSAT evaluation as well as my co-authors, Emir Demirovic and Peter Stuckey! I am currently on a holiday, but once I get back I will put up Loandra on github as well. It will also eventually be made available here.

EDIT: Loandra is now available at: https://github.com/jezberg/loandra and on the software pages.

 

The conferment ceremony of the Faculty of Philosophy

About a month ago I participated in the conferment ceremony of the Faculty of Philosophy, a formal, and very traditional three day celebration during which I was granted the rights to wear the symbols of my academic degree, a doctoral hat and a doctoral sword.
The three days were filled with dinners and other festivities, culminating in a formal ball and a night procession through the center of Helsinki. I’d like to thank all of the organizers of the event!  I had a great time. The ceremony will probably be up there amongst the most unique experiences of my life, I mean when I am I ever going to be a part of a que consisting of 200+ masters and doctors dancing through the streets of Helsinki again.

All of the pictures here were taken by the talented people at Bonafide Creatives. Check them out at: https://www.bonafideweddings.fi/.

 

My thesis won an award

My PhD thesis: Solving Optimization Problems via Maximum Satisfiability : Encodings and Re-Encodings (available from e-thesis) was awarded one of four doctoral dissertation awards for 2018 of The University of Helsinki. I am grateful and honoured by this recognition. Thank you to everyone who played a role in my nomination and congratulations to my three other fellow recipients.

More information can be found in the University’s own news story.

My thesis won an award

I was honoured to receive an e-mail on Friday informing me that my PhD-thesis: Solving Optimization Problems via Maximum Satisfiablity: Encodings and Re-Encodings has been recognized with an outstanding doctoral dissertation award by the Doctoral School of Natural Sciences at the University of Helsinki. I thank the school for this honour and everyone involved in nominating my thesis.