Wednesday, December 12, 2018

CS@GSSI: Highlights for 2018

It is the time of the year when one sees "Best of 2018 in X (for some X)"/"Year in Review" articles appear just about everywhere in print and on the internet. Since I need to deliver a ten-minute presentation to the Scientific Advisory Board of the  Gran Sasso Science Institute (GSSI) discussing the highlights in 2018 for the computer science group, I thought that it might be a good idea to prepare for that task by following the trend and dumping some of my thoughts in this post.

So what were the main achievements of the CS@GSSI group in 2018? With only ten minutes at my disposal, I needed to make some hard choices and I decided to focus on the kudos that were bestowed on our students. After all, "our students' success is our success" and the GSSI is also an international PhD school.

Before I do so, however, let me give a bird's eye view of the research activity of the group and of the changes in personnel we have had in 2018. In November 2017, the group consisted of two full professors (one, Michele Flammini,  on loan from the University of L'Aquila), one tenure-track assistant professor, two non-tenute-track assistant professors and one postdoc. Those six people had to manage about 40 PhD students at various stages in their doctoral studies and this task could only be achieved with the help of external supervisors. Today, the faculty members in the group have not changed, but  the number of postdocs has grown to eight from November 2018. (We have been very lucky in hiring some superb young scientists!) At the same time, we have admitted eight new PhD students, seven of whom are from outside Italy and three are women, and are happy to have Shantanu Das (Marseille) as a visiting professor for a few months.


Despite the work resulting from having to manage a fairly large number of PhD students, give courses and deal with the administrative red tape that accompanies just about everything at an Italian university, my colleagues at CS@GSSI and our students managed to produce a substantial number of high-quality publications including 16 journal papers, 52 conference papers, four book chapters, two edited volumes and five refereed short abstracts/posters. (Note that these are publications with GSSI affiliation, so there is only one paper authored by one of the new seven postdocs.)

Essentially every high-quality conference in the fields of research covered by CS@GSSI has seen the presentation of at least one paper from the group. To wit, my colleagues published seven papers in top AI conferences (AAAI, AAMAS, IJCAI), seven papers in high-quality TCS conferences (including STOC and ICALP), two papers in the top SE conference (ICSE) and one in the top conference on foundations of programming languages (POPL). All the journal papers are in high-class outlets. Here let me just highlight that I have covered the result of a collaborative effort between researchers in algorithms and software engineering elsewhere.

Two of the papers are co-authored with researchers from the Urban Studies group at at the GSSI, and witness the cross-disciplinary work carried out by my colleagues in topics such as Smart Cities.

Student awards and honours

It is hard to choose what student achievements to highlight, so let me say that all our PhD students had  an excellent year and that the three contributions below are just a small sample of the work done by the PhD students at the institute.
  • CS@GSSI student Ahmed Abdelsalam has contributed to the proposal that won the first prize at the Interworking stream at the SoftFIRE Challenge 2018, which carries a 40,000 € prize. Ahmed's work on IPv6 Segment Routing (SRv6) and his recently developed SRv6-aware version of the network intrusion and detection system Snort played a key role in the award-winning proposal. Every Linux user is running GSSI software! Ahmed's network intrusion and detection system might well be the work carried out at the GSSI that is most widely used worldwide and has the most impact on a day to day basis. Ahmed now works for Cisco in Rome. 
  • CS@GSSI student Emilio Cruciani has published papers in the top conference in software engineering (ICSE) (jointly with  fellow student Roberto Verdecchia, Breno Miranda and Antonia Bertolino; see here for a post I wrote on one of the two papers), and in two of the three top conferences in the theory of artificial intelligence (AAAI and AAMAS). To put these achievements in perspective, a conference like AAAI has over 7,000 submissions and an acceptance rate of around 16%.
  • CS@GSSI student Roberto Verdecchia, whom I already mentioned in the previous highlight, has received the Early Career Researcher Award from the International Conference on Software Architectures. 
Let me also mention that my colleagues also receive awards for their sterling service to the community. By way of example, Catia Trubiani received an Exceptional Reviewer Award from ICSA. 
Software tools

Despite its very limited size, CS@GSSI devotes a substantial amount of effort to tool development. I have already mentioned the contribution given by Ahmed to the Linux kernel (IPv6 SHR). Other software tools developed by my colleagues include:
  • Omar Inverso's Lazy-CSeq, an award-winning automated analysis of complex concurrent programs, and his CSeq-fpmath and CSeq-fpmath-ILP, for the automated verification of data-intensive programs such as control system software;
  • a prototype tool for the automated analysis of multi-agent-based models, developed by Luca Di Stefano, Omar and Rocco De Nicola. 
Addendum dated 16 December 2018:  Omar Inverso's Lazy-CSeq has just received yet another accolade! It has won a Silver Medal at the 2019 8th International Competition on Software Verification (SV-COMP 2019). As can be seen from the results of the competition available here, Omar's tool Lazy-CSeq came second in the category ConcurrencySafety and was beaten only by a tool developed by a Chinese team from Tsinghua University (which is widely considered the best technical university in China).

The CS@GSSI group organized the following events in 2018:
All the events were well attended and fruitful. (To whet you appetite, let me say that we will be organizing SIROCCO 2019.)

Collaborations with other groups at the GSSI

I think that it is fair to say that the CS group at the GSSI is playing the role of glue within the institute: like Nokia claimed it used to do, it is connecting people! In fact, I do believe that CS is and will increasingly become the hub of the institute. Here are some examples to substantiate my claim, in addition to the two papers published jointly with researchers in Urban Studies.
  • We have run joint seminars with Urban Studies and Mathematics (and brought an ICM 2018 invited section speaker to the GSSI). 
  • We have a joint postdoc with Urban Studies (Geotouch project on tourist flow). 
  • We have submitted two joint project proposals with Urban Studies. 
  • Catia Trubiani participates in a  COST action related to machine learning with researchers in the Astroparticle Physics group. 
Submission of grant proposals

We have at least eight grant proposals under evaluation, submitted to funding agencies in Italy, European Union and Iceland. Moreover, we have received funding for one PhD position from a local start-up company and from the municipality of L'Aquila for a project on an innovative platform for tourism.

Of course, I hope that some of those grant applications will be successful. However, money isn’t an end in itself. Lots of it does not necessarily lead to good, let alone great, science! In my career, I have seen richly funded projects produce much less than expected (and sometimes no science at all), whereas some grassroots projects with little or no funding have led to great advances.

I do hope that, regardless of the funding situation, my colleagues will go from strength to strength, produce the best work they can and serve as role models for the PhD students at the GSSI. One cannot ask for more.

Self-evaluation for 2018
  • The CS group is already a productive and internationally respected group, despite its very limited size.
  • We are lucky to have excellent students, and brilliant postdocs and young faculty.
  • CS is already a hub at GSSI, but is grossly over-committed. We need to hire a good number of excellent faculty soon! If you are interested, send an expression of interest.

The future

I think that 2019 will be a key year for the growth of CS@GSSI. I looked at my crystal ball and made a few predictions, but I prefer to air them during the meeting with the Scientific Advisory Board of the GSSI on Saturday without making them public on the internet. After all, "verba volant, scripta manent!"

I just hope that the GSSI will continue to give us the freedom to hire the best people we can find and allow us to do our work. 

Wednesday, December 05, 2018

Two papers by GSSI researchers at AAAI 2019

The main track of AAAI 2019 will feature the presentation of two papers by CS@GSSI researchers. The two papers are
The paper by Gianlorenzo, Martin and Lorenzo (who is a CS@GSSI alumnus)  contributes to the study of one of the main tools in the analysis of social networks, viz. centrality metrics. Since central nodes are very influential in their network, increasing the centrality of a network user is a widely studies optimization problem in network analysis. Gianlorenzo, Martin and Lorenzo have studied the centrality maximization problem in undirected networks for one of the most important shortest-path-based centrality measures, namely the coverage centrality. They give several hardness results, approximation algorithms and an experimental study of their effectiveness.

The paper by Emilio, Emanuele and Giacomo analyzes the behaviour of a simple majority-based dynamics on a class of networks that present a clustered structure. By combining symmetry-breaking techniques and concentration of probability arguments with a linear algebraic approach, it provides the first symmetry-breaking analysis of dynamics for non-consensus problems on non-complete topologies. The analysis shows that, when the agents of the networks randomly initialize their states, the 2-Choices dynamics makes the network quickly converge to a configuration where the agents have a state that identifies the cluster to which  they belong. The 2-Choices dynamics can be seen as a simple distributed Label Propagation Algorithm (a widely used class of heuristics for graph clustering) with quasi-linear message complexity. In this setting, the paper represents the first rigorous theoretical result. Moreover, in the context of evolutionary biology, it gives a proof of principle of sympatric/parapatric speciation, in which there is no complete geographical isolation between the species: No simple dynamics was proposed before to explain such a fundamental phenomenon.

Congratulations to Emilio, Gianlorenzo and their coauthors! It is always a pleasure to see young researchers in one's group succeed and develop their careers. Emilio Cruciani is a beginning third-year student who already has an impressive track record of high-quality publications. Keep him in mind for postdoctoral and tenure-track positions, once he finishes his studies!

The AAAI conference promotes research in artificial intelligence and is one of the premier conferences in AI, where researchers, practitioners, and scientists meet to present and discuss most recent trends and results in the field of artificial intelligence. This year it received a record number of over than 7,700 submissions of which 1,150 were accepted (with an acceptance rate of 16.2%). The list of accepted papers is at…/uplo…/2018/11/AAAI-19_Accepted_Papers.pdf.

Thursday, November 29, 2018

Calls for expressions of interest in academic positions in CS at the Gran Sasso Science Institute

The CS group at the Gran Sasso Science Institute has issued a call for expressions of interest in tenured/tenure-track academic positions. One call is for an associate or full professor position in the field of machine learning. The other is for positions at all academic levels in the areas of algorithms, formal methods (broadly construed) and software engineering.

The GSSI is an international PhD school and a centre for advanced studies in physics, mathematics, computer science and social sciences. It offers a truly international research environment and we are planning to grow substantially in CS in the coming years. Do consider expressing your interest for a position with us and spread the word!

Wednesday, October 24, 2018

One PhD position at the School of Computer Science, Reykjavik University

The following call for a PhD position at Reykjavik University might be of interest to some of your students. Feel free to distribute it as you see fit.

Open Problems in the Equational Logic of Processes

School of Computer Science, Reykjavik University
One PhD Position

Applications are invited for one PhD position at the School of Computer Science, Reykjavik University.  The position is part of a research project funded by the Reykjavik University Research Fund, under the direction of Luca Aceto (Reykjavik University) and Anna Ingolfsdottir (Reykjavik University) in cooperation with Bas Luttik (TU Eindhoven) and Alexandra Silva (University College London). The overarching goal of this project is to solve some of the challenging open problems in the equational axiomatization of behavioural equivalences over process calculi. Interested applicants can contact Luca Aceto (email: for further details on the research proposal.

The successful candidate will benefit from, and contribute to, the research environment at the Icelandic Centre of Excellence in Theoretical Computer Science (ICE-TCS). For information about ICE-TCS and its activities, see

Moreover, she/he will cooperate with Bas Luttik and Alexandra Silva  during the project work and will benefit from the interaction with their research groups at TU Eindhoven and University College London. The PhD student will also have a chance to interact with Clemens Grabmayer and the CS group at the Gran Sasso Science Institute (, L'Aquila, Italy.

Qualification requirements

Applicants for the PhD fellowship should have, or be about to obtain, an MSc degree in Computer Science, or closely related fields. Some background in concurrency theory and mathematical competence are desirable.

The PhD position provides a stipend of 420,000 ISK (roughly 3,110 € at the current exchange rate) per month before taxes, for three years, starting as early as possible.  In addition, the student will have 300,000 ISK per year available for research-related travel.

Application details

Interested applicants should send their CV, including a list of publications, in PDF to all the addresses below, together with a statement outlining their suitability for the project and the names of at least two referees.

Luca Aceto

Anna Ingolfsdottir

Bas Luttik

Alexandra Silva

We will start reviewing applications as soon as they arrive and will continue to accept applications until the position is filled. We strongly encourage interested applicants to send their applications as soon as possible and no later than 23 November 2018.

Wednesday, October 10, 2018

Call for nominations for the Presburger Award 2019

Anca Muscholl asked me to advertise the call for nominations for the Presburger Award. I hope that members of the TCS community will nominate many of the young scientists (see the text below for the definition of "young") doing exciting work in TCS.  I wish Anca, Jukka and Thore good luck with their work, as I am sure they will be faced with some difficult choices.

Starting in 2010, the European Association for Theoretical Computer Science
(EATCS) established the Presburger Award. The Award is conferred annually at
the International Colloquium on Automata, Languages and Programming (ICALP) to a young scientist (in exceptional cases to several young scientists) for outstanding contributions in theoretical computer science, documented by a published paper or a series of published papers.

The Award is named after Mojżesz Presburger who accomplished his path-
breaking work on decidability of the theory of addition (which today is called
Presburger arithmetic) as a student in 1929.

Nominations for the Presburger Award can be submitted by any member or
group of members of the theoretical computer science community except the nominee and his/her advisors for the master thesis and the doctoral dissertation. Nominated scientists have to be at most 35 years at the time of the deadline of nomination (i.e., for the Presburger Award of 2019 the date of birth should be in 1983 or later). The Presburger Award Committee of 2019 consists of Thore Husfield (Lund University and IT University of Copenhagen), Anca Muscholl (LaBRI) and Jukka Suomela (Aalto, chair). Nominations, consisting of a two page justification and (links to) the respective papers, as well as additional supporting letters, should be sent by e-mail to:

The subject line of every nomination should start with Presburger Award 2019,
and the message must be received before December 31st, 2018.

The award includes an amount of 1000 Euro and an invitation to ICALP 2019
for a lecture.

Saturday, September 15, 2018

PhD position in "Concurrency, logic and type systems" at the University of Groningen, The Netherlands

Jorge Pérez has asked me to share the following advertisement for a PhD position in his group at the University of Groningen. I trust that this might be of interest to some of the readers or this blog or their students working in concurrency theory, semantics of programming languages and types. The position is supported by a prestigious NWO VIDI career grant recently awarded to Jorge the project "Unifying Correctness for Communicating Software". Feel free to spread this call for PhD applications as you see fit. The deadline is in roughly two weeks.

(Posted: August 31, 2018)
University of Groningen, The Netherlands

We are searching for one four-year PhD position on the topics of concurrency, logic, type systems, and programming languages.

You will contribute to rigorously comparing different type systems for message-passing programs, such as session types.
These comparisons will use as reference a correspondence known as "propositions as sessions", which connects concurrency and logic in the style of the well-known Curry-Howard correspondence.
We will use the resulting comparisons to streamline existing type systems, and to guide the development of verification tools for message-passing programs.

Your PhD research will be embedded in the project "Unifying Correctness for Communicating Software", a VIDI career grant recently awarded to Dr. Jorge A. Perez by the NWO (Netherlands Organization for Scientific Research).
As such, you will join a dynamic, quickly growing research group; within the project, you will collaborate with research partners both in the Netherlands (e.g., at CWI Amsterdam) and abroad.

- Qualifications

You have an MSc degree (or equivalent) in Computer Science, Logic, Mathematics, or Artificial Intelligence, and experience in at least one, preferably two or more, of the following:

• Semantics of programming languages
• Program verification, type systems, and/or typed programming languages
• Concurrency theory and/or process calculi
• The Curry-Howard isomorphism ("propositions as types")
• Modal/substructural logics and (their) proof theory

Female candidates are encouraged to apply.

- Application and Additional Information

For further details on the position and the application procedure, please visit

For further information and expressions of interest, contact Jorge A. Perez (
See also

You may apply until 1 October 23:59h / before 2 October 2018 (Dutch local time).

Friday, September 14, 2018

Shortest-path algorithms applied to software engineering: A tale of cross fertilization within CS

These days, it looks as if many of us are supposed to undertake, or are expected to promise to carry out, interdisciplinary research. However, I have sometimes witnessed first-hand a lack of curiosity even to cross  the (often artificial) boundaries between areas of research within (theoretical) computer science and/or mathematics. This conservative attitude is reasonable at times, and at various stages of one's academic career, and is partly justified by the pressure to produce research output that most of us feel. I freely admit, though, that  I felt a bit uneasy when a colleague from "volume A TCS" told me at an ICALP conference that he was not going to attend  an invited talk delivered by a "volume B researcher" because that would be like going to a talk in the life sciences. (By the way, that invited talk was excellent and was delivered by a charismatic scientist. The colleague in question missed an intellectual treat.)

Perhaps naively, I feel that one of the reasons why we are in academia is that we are intellectually curious and that we should try to explain what we do to one another at least across the various disciplines within CS. Hence, I was very pleased to see this paper, which will appear in the prestigious IEEE Transactions on Software Engineering (behind the usually hefty paywall of the IEEE, alas). The paper stems from discussions between Mattia D'Emidio (a researcher in algorithmics) and Ludovico Iovino (a researcher in software engineering) who were sharing a basement office at the Gran Sasso Science Institute at the time. Those exchanges of ideas led eventually to the development of a framework that uses classic shortest-path algorithms in the selection of optimal chains of model transformations in model-driven SE. More specifically, those colleagues of mine show how to reduce the problem of computing chains of model transformations
that maximize the coverage to a shortest-path problem on weighted graphs. Moreover, they evaluate the practical effectiveness of the proposed approach by applying their automated methodology to a large set of experiments.

IMHO, this is a pleasing example of the kind of serendipitous collaboration that can arise when we are willing to have an open mind and look for possible applications to our techniques in other fields. Kudos to Ludovico, Mattia and their co-authors for going all the way and for publishing their article in a coveted outlet. I look forward to seeing more examples of cross fertilization within CS@GSSI.

Addendum 26/9/2018: Ludovico and Mattia kindly sent me two photos they took while the work was ongoing. (The all-important coffee machine is not pictured.)