21 February 2017 ~ 0 Comments

Netonets @ NetSci 2017: Call for Contributions!

We are delighted to invite submissions for

Network of Networks
7th Edition – Satellite Symposium at NetSci2017

taking place in JW Marriott Indianapolis, Indiana, United States,
on June 20th, 2017.

We invite you to submit a 300 word abstract including one descriptive figure using our EasyChair submission link:

Deadline for submission: April 21st, 2017.
Notification of acceptance will be sent out by April 28th, 2017.

Further Information at: http://www.netonets.org/events/netonets2017

For the seventh time, it is our pleasure to bring together pioneer work in the study of networks of networks. Networks of networks are networks in which the nodes may be connected through different relations, are part of interdependent layers and connected by higher order dynamics. They can represent multifaceted social interactions, critical infrastructure and complex relational data structures. In our call, we are looking for a diversity of research contributions revolving around networks of networks of any kind: in social media, in infrastructure, in culture. We are particularly keen in receiving works raising novel issues and provocative queries in the investigation of networks of networks, as well as new contributions tackling these challenges. How do networks of networks change the paradigm of established problems like percolation or community detection? How are we shifting our thoughts to be ready for this evolution? Running parallel to NetSci, the top network science conference, this event provides a valuable opportunity to connect with leading researchers in complex network science.

Confirmed Keynote:

Marta Gonzales – MIT
Gareth Baxter – University of Aveiro
Romualdo Pastor-Satorras – Universitat Politècnica de Catalunya
Paul Hines – University of Vermont (UNCONFIRMED)

The final program will strive for the inclusion of contributions from different research fields, creating an interdisciplinary dialogue about networks of networks.

Best regards,
The Netonets organizers,

Antonio Scala, La Sapienza – antonio.scala.phys@gmail.com
Gregorio D’Agostino, ENEA – gregorio.dagostino@enea.it
Michele Coscia, Harvard University – michele_coscia@hks.harvard.edu
Przemysław Kazienko, Wroclaw University of Technology – przemyslaw.kazienko@pwr.edu.pl

Continue Reading

09 June 2016 ~ 0 Comments

Netsci 2016 Report


Another NetSci edition went by, as interconnected as ever. This year we got to enjoy Northeast Asia, a new scenario for us network scientists, and an appropriate one: many new faces popped up both among speakers and attendees. Seoul was definitely what NetSci needed at this time. I want to spend just a few words about what impressed me the most during this trip — well, second most after what Koreans did with their pizzas: that is unbeatable. Let’s go chronologically, starting with the satellites.

You all know I was co-organizing the one on Networks of networks (you didn’t? Then scroll down a bit and get informed!). I am pleased with how things went: the talks we gathered this year were most excellent. Space constraints don’t allow me to give everyone the attention they deserve, but I want to mention two. First is Yong-Yeol Ahn, who was the star of this year. He gave four talks at the conference — provided I haven’t miscounted — and his plenary one on the analysis of the Linkedin graph was just breathtaking. At Netonets, he talked about the internal belief network each one of us carries in her own brain, and its relationship with how macro societal behaviors arise in social networks. An original take on networks of networks, and one that spurred the idea: how much are the inner workings of one’s belief network affected by the metabolic and the bio-connectome networks of one own body? Should we study networks of networks of networks? Second, Nitesh Chawla showed us how high order networks unveil real relationships among nodes. The same node can behave like it is many different ones, depending on which of its connections we are considering.


Besides the most awesome networks of networks satellite, other ones caught my attention. Again, space is my tyrant here, so I get to award just one slot, and I would like to give it to Hyejin Youn. Her satellite was on the evolution of technological networks. She does amazing things tracking how the patent network evolved from the depths of 1800 until now. The idea is to find viable innovation paths, and to predict which fields will have the largest impact in the future.

When it comes to the plenary sessions, I think Yang-Yu Liu stole the spotlight with a flashy presentation about the microcosmos everybody carries in their guts. The analysis of the human microbiome is a very hot topic right now, and it pleases me to know that there is somebody working on a network perspective of it. Besides scientific merits, whoever extensively quotes Minute Earth videos — bonus points for it being the one about poop transplants — has my eternal admiration. I also want to highlight Ginestra Bianconi‘s talk. She has an extraordinary talent in bringing to network science the most cutting edge aspects of physics. Her line of research combining quantum gravity and network geometry is a dream come true for a physics nerd like myself. I always wished to see advanced physics concepts translated into network terms, but I never had the capacity to do so: now I just have to sit back and wait for Ginestra’s next paper.


What about contributed talks? The race for the second best is very tight. The very best was clearly mine on the link between mobility and communication patterns, about which I showed a scaling relationship connecting them (paperpost). I will be magnanimous and spare you all the praises I could sing of it. Enough joking around, let’s move on. Juyong Park gave two fantastic talks on networks and music. This was a nice breath of fresh air for digital humanities: this NetSci edition was orphan of the great satellite chaired by Max Schich. Juyong showed how to navigate through collaboration networks on classical music CDs, and through judge biases in music competitions. By the way, Max dominated — as expected — the lighting talk session, showing some new products coming from his digital humanities landmark published last year in Science.  Tomomi Kito was also great: she borrowed the tools of economic complexity and shifted her focus from the macro analysis of countries to the micro analysis of networks of multinational corporations. A final mention goes to Roberta Sinatra. Her talk was about her struggle into making PhD committees recognize that what she is doing is actually physics. It resonates with my personal experience, trying to convince hiring committees that what I’m doing is actually computer science. Maybe we should all give up the struggle and just create a network science department.

And so we get to the last treat of the conference: the Erdos-Renyi prize, awarded to the most excellent network researcher under the age of 40. This year it went to Aaron Clauset, and this pleases me for several reasons. First, because Aaron is awesome, and he deserves it. Second, because he is the first computer scientist who is awarded the prize, and this just gives me hope that our work too is getting recognized by the network gurus. His talk was fantastic on two accounts.


For starters, he presented his brand new Index of Complex Networks. The interface is pretty clunky, especially on my Ubuntu Firefox, but that does not hinder the usefulness of such an instrument. With his collaborators, Aaron collected the most important papers in the network literature, trying to find a link to a publicly available network. If they were successful, that link went in the index, along with some metadata about the network. This is going to be a prime resource for network scientists, both for starting new projects and for the sorely needed task of replicating previous results.

Replication is the core of the second reason I loved Aaron’s talk. Once he collected all these networks, for fun he took a jab at some of the dogmas of networks science. The main one everybody knows is: “Power-laws are everywhere”. You can see where this is going: the impertinent Colorado University boy showed that yes, power-laws are very common… among the 5-10% of networks in which it is possible to find them. Not so much “everywhere” any more, huh? This was especially irreverent given that not so long before Stefan Thurner gave a very nice plenary talk featuring a carousel of power laws. I’m not picking sides on the debate — I feel hardly qualified in doing so. I just think that questioning dearly held results is always a good thing, to avoid fooling ourselves into believing we’ve reached an objective truth.


Among the non-scientific merits of the conference, I talked with Vinko Zlatic about the Croatian government on the brink of collapse, spread the search for a new network scientist by the Center for International Development, and discovered that Korean pizzas are topped with almonds (you didn’t really think I was going to let slip that pizza reference at the beginning of the post, did you?). And now I made myself sad: I wish there was another NetSci right away, to shove my brain down into another blender of awesomeness.  Oh well, there are going to be plenty of occasions to do so. See you maybe in Dubrovnik, Tel-Aviv or Indianapolis?

Continue Reading

20 May 2016 ~ 0 Comments

Program of Netonets 2016 is Out!

As announced in the previous post, the symposium on networks of networks is happening in less than two weeks: May 31st @ 9AM, room Dongkang C of the K-Hotel Seoul, South Korea. Przemek Kazienko, Gregorio D’Agostino and I have a fantastic program and set of speakers to keep you entertained on multilayer, interdependent and multislice networks. Take a look for yourself!

Session I

9:00 – 9:15: Room set up
9:15 – 9:30: Welcome from the organizers
9:30 – 10:15: Invited I: Yong-Yeol Ahn: Dynamics of social network of belief networks
10:15 – 11:00: Invited II: Luca Maria Aiello: The Nature of Social Links

11:00 – 11:30: Coffee Break

Session II

11:30 – 12:15: Invited III: Jianxi Gao: Networks of Networks: From Structure to Dynamics
12:15 – 13:00: Invited IV: Tomasz Kajdanowicz: Fusion methods for classification in multiplex networks

13:00 – 14:30: Lunch Break

Session III

14:30 – 15:15: Invited V: Michael Danziger: Beyond interdependent networks
15:15 – 15:35: Contributed I: Bruno Coutinho: Greedy Leaf Removal on Hypergraphs
15:35 – 15:55: Contributed II: Yong Zhuang: Complex Contagions in Clustered Random Multiplex Networks

15:55 – 16:30: Coffee Break

Session IV

16:30 – 17:15: Invited VI: Nitesh Chawla: From complex interactions to networks: the higher-order network representation

17:15 – 18:00: Round table – Open discussion
18:00 – 18:15: Organizers wrap up

Remember to register to the main NetSci conference if you want to attend.

Incidentally, the end of May is going to be a rather busy period for me. Besides co-organizing Netonets and speaking at the main Netsci conference, I’m going to present also at the Core50 conference in Louvain-la-Neuve, Belgium, on the role of social and mobility networks in shaping the economic growth of a country. Thanks to Jean-Charles Delvenne for inviting me!

I hope to see many of you there!

Continue Reading

17 March 2016 ~ 0 Comments

Networks of Networks @ NetSci 2016

EDIT: Deadlines & speakers updated. Submission deadline is on April 27th, notification on April 29th.


Dear readers of this blog — yes, both of you –: it’s that time of the year again. As tradition dictates, I’m organizing the Networks of Networks symposium, satellite event of the NetSci conference.

Networks of networks are structures in which the nodes may be connected through different relations. They can represent multifaceted social interaction, critical infrastructure and complex relational data structures. In the symposium, we are looking for a diversity of research contributions revolving around networks of networks of any kind: in social media, in infrastructure, in culture. The call for contributed talks is OPEN, and you can submit your abstract here: https://easychair.org/conferences/?conf=non2016

The deadline for submissions is April 15th, 2016 April 27th, 2016, just a month from now. We will notify acceptance by April 22nd, 2016 April 29th, 2016.

Here’s my handy guide to few of the many reasons to come:

  • Networks of networks are awesome, a hot topic in network science and a lot of super smart people work on them. You wouldn’t pass the opportunity to mingle with them, would you?
  • We have a lineup of outstanding confirmed keynotes this year — truth to be told, we have that every year:
  • This year NetSci will take place at the K-Hotel, Seoul, Korea (South, whew…). You really should not miss this occasion to visit such fascinating place.

The Networks of Networks symposium will be held on May 31st, 2016. The full conference, including all satellites, runs from May 30th to June 3rd. You can find all relevant information for the conference in the official NetSci website. Our symposium has a website too: check it out. In it, you will find also the fundamental information about all the people organizing this event with me: without them none of this would be possible. Here they are:

And also a list of other people, helping with their ideas, time and enthusiasm:

  • Matteo Magnani
  • Ian Dobson
  • Luca Rossi
  • Leonardo Duenas-Osorio
  • Dino Pedreschi
  • Guido Caldarelli
  • Vito Latora

Hope to see many of you in Korea!

Continue Reading

18 November 2015 ~ 0 Comments

Evaluating Prosperity Beyond GDP

When reporting on economics, news outlets very often refer to what happens to the GDP. How is policy X going to affect our GDP? Is the national debt too high compared to GDP? How does my GDP compare to yours? The concept lurking behind those three letters is the Gross Domestic Product, the measure of the gross value added by all domestic producers in a country. In principle, the idea of using GDP to take the pulse of an economy isn’t bad: we count how much we can produce, and this is more or less how well we are doing. In practice, today I am jumping on the huge bandwagon of people who despise GDP for its meaningless, oversimplified and frankly suspicious nature. I will talk about a paper in which my co-authors and I propose to use a different measure to evaluate a country’s prosperity. The title is “Going Beyond GDP to Nowcast Well-Being Using Retail Market Data“, my co-authors are Riccardo Guidotti, Dino Pedreschi and Diego Pennacchioli, and the paper will be presented at the Winter edition of the Network Science Conference.

GDP is gross for several reasons. What Simon Kuznets said resonates strongly with me, as already in the 30s he was talking like a complexity scientist:

The valuable capacity of the human mind to simplify a complex situation in a compact characterization becomes dangerous when not controlled in terms of definitely stated criteria. With quantitative measurements especially, the definiteness of the result suggests, often misleadingly, a precision and simplicity in the outlines of the object measured. Measurements of national income are subject to this type of illusion and resulting abuse, especially since they deal with matters that are the center of conflict of opposing social groups where the effectiveness of an argument is often contingent upon oversimplification.


In short, GDP is an oversimplification, and as such it cannot capture something as complex as an economy, or the multifaceted needs of a society. In our paper, we focus on some of its specific aspects. Income inequality skews the richness distribution, so that GDP doesn’t describe how the majority of the population is doing. But more importantly, it is not possible to quantify well-being just with the number of dollars in someone’s pocket: she might have dreams, aspirations and sophisticated needs that bear little to no correlation with the status of her wallet. And even if GDP was a good measure, it’s very hard to calculate: it takes months to estimate it reliably. Nowcasting it would be great.

And so we tried to hack our way out of GDP. The measure we decided to use is the one of customer sophistication, that I presented several times in the past. In practice, the measure is a summary of the connectivity of a node in a bipartite network*. The bipartite network connects customers to the products they buy. The more variegated the set of products a customer buys, the more complex she is. Our idea was to create an aggregated version at the network level, and to see if this version was telling us something insightful. We could make a direct correlation with the national GDP of Italy, because the data we used to calculate it comes from around a half million customers from several Italian regions, which are representative of the country as a whole.


The argument we made goes as follows. GDP stinks, but it is not 100% bad, otherwise nobody would use it. Our sophistication is better, because it is connected to the average degree with which a person can satisfy her needs**. Income inequality does not affect it either, at least not in trivial ways as it does it with GDP. Therefore, if sophistication correlates with GDP it is a good measure of well-being: it captures part of GDP and adds something to it. Finally, if the correlation happens with some anticipated temporal shift it is even better, because GDP pundits can just use it as instantaneous nowcasting of GDP.

We were pleased when our expectations met reality. We tested several versions of the measure at several temporal shifts — both anticipating and following the GDP estimate released by the Italian National Statistic Institute (ISTAT). When we applied the statistical correction to control for the multiple hypothesis testing, the only surviving significant and robust estimate was our customer sophistication measure calculated with a temporal shift of -2, i.e. two quarters before the corresponding GDP estimate was released. Before popping our champagne bottles, let me write an open letter to the elephant in the room.


As you see from the above chart, there are some wild seasonal fluctuations. This is rather obvious, but controlling for them is not easy. There is a standard approach — the X-13-Arima method — which is more complicated than simply averaging out the fluctuations. It takes into account a parameter tuning procedure including information we simply do not have for our measure, besides requiring observation windows longer than what we have (2007-2014). It is well possible that our result could disappear. It is also possible that the way we calculated our sophistication index makes no sense economically: I am not an economist and I do not pretend for a moment that I can tell them how to do their job.

What we humbly report is a blip on the radar. It is that kind of thing that makes you think “Uh, that’s interesting, I wonder what it means”. I would like someone with a more solid skill set in economics to take a look at this sophistication measure and to do a proper stress-test with it. I’m completely fine with her coming back to tell me I’m a moron. But that’s the risk of doing research and to try out new things. I just think that it would be a waste not to give this promising insight a chance to shine.

* Even if hereafter I talk only about the final measure, it is important to remark that it is by no means a complete substitute of the analysis of the bipartite network. Meaning that I’m not simply advocating to substitute a number (GDP) for another (sophistication), rather to replace GDP with a fully-blown network analysis.

** Note that this is a revealed measure of sophistication as inferred by the products actually bought and postulating that each product satisfies one or a part of a “need”. If you feel that the quality of your life depends on you being able to bathe in the milk of a virgin unicorn, the measure will not take into account the misery of this tacit disappointment. Such are the perils of data mining.

Continue Reading

29 May 2015 ~ 0 Comments

Networks of Networks – NetSci 2015

The time has finally come! The NetSci conference—the place to be if you are interested in complex networks—is happening next week, from June 1st to June 5th. The venue is in Zaragoza, Spain. You can get all the information you need about the event from the official website. For the third year, I am co-organizing one of its satellite events: the Multiple Network Modeling, Analysis and Mining symposium, this year held jointly with Networks of Networks. The satellite will take place on June 2nd. As I previously said, unfortunately I am not going to be physically present in Span, and that makes me sad, because we have a phenomenal program this year.

We have four great invited speakers: Giovanni Sansavini, Rui Carvalho, Arunabha Sen and Katharina Zweig. It is a perfect mix between the infrastructure focus of the networks of networks crowd and the multidisciplinary approach of multiple networks. Sansavini works on reliability and risk engineering, while Carvalho focuses on characterizing and modeling networks in energy. Sen and Zweig provide their outstanding experience in the fields of computer networks and graph theory.

Among the contributed talks I am delighted to see that many interesting names from the network analysis crowd decided to send their work to be presented in our event. Among the highlights we have a contribution from the group of Mason Porter, who won last year’s Erdos Prize as one of the most outstanding young network scientists. I am also happy to see contributions from the group of Cellai and Gleeson, with whom I share not only an interest on multiplex networks, but also on internet memes. Contributions from groups lead by heavyweights like Schweitzer and Havlin are another sign of the attention that this event has captured.

I hope many of you will attend this seminar. You’ll be in good hands: Gregorio D’Agostino, Przemyslaw Kazienko and Antonio Scala will be much better hosts than I can ever be. I am copying here the full program of the event. Enjoy Spain!

NoN’15 Program

Session I

9.00 – 9.30 Speaker Set Up

9.30 – 9.45 Introduction: Welcome from the organizers, presentation of the program

9.45 – 10.15 Keynote I: Giovanni Sansavini. Systemic risk in critical infrastructures

10.15 – 10.35 Contributed I: Davide Cellai and Ginestra Bianconi. Multiplex networks with heterogeneous activities of the nodes

10.35 – 10.55 Contributed II: Mikko Kivela and Mason Porter. Isomorphisms in Multilayer Networks

10.55 – 11.30 Coffee Break

Session II

11.30 – 12.00 Keynote II: Rui Carvalho, Lubos Buzna, Richard Gibbens and Frank Kelly. Congestion control in charging of electric vehicles

12.00 – 12.20 Contributed III: Saray Shai, Dror Y. Kenett, Yoed N. Kenett, Miriam Faust, Simon Dobson and Shlomo Havlin. A critical tipping point in interconnected networks

12.20 – 12.40 Contributed IV: Adam Hackett, Davide Cellai, Sergio Gomez, Alex Arenas and James Gleeson. Bond percolation on multiplex networks

12.40 – 13.00 Contributed V: Marco Santarelli, Mario Beretta, Giorgio D’Urbano, Lorenzo Spina, Renato De Leone and Emilia Marchitto. Soccer and networks: changing the way of playing soccer through GPS, video analysis and social networks

13.00 – 14.30 Lunch

Session III

14.30 – 15.00 Keynote III: Arunabha Sen. Strategic Analysis and Design of Robust and Resilient Interdependent Power and Communication Networks with a New Model of Interdependency

15.00 – 15.20 Invited I: Alfonso Damiano,Univ. di Cagliari – Electric Market – Italy; Antonio Scala CNR-ICS, IMT, LIMS

15.20 – 15.40 Contributed VI: Rebekka Burkholz, Antonios Garas, Matt V Leduc, Ingo Scholtes and Frank Schweitzer. Cascades on Multiplexes with Threshold Feedback

15.40 – 16.00 Contributed VII: Soumajit Pramanik, Maximilien Danisch, Qinna Wang, Jean-Loup Guillaume and Bivas Mitra. Analyzing the Impact of Mentioning in Twitter

16.00 – 16.30 Coffee Break

Session IV

16.00 – 16.30 Keynote IV: Katharina Zweig. Science-theoretic musings on the analysis of networks (of networks)

16.30 – 16.50 Contributed VIII: Vinko Zladic, Sebastian Krause, Michael Danziger. Avoidable colors percolation

16.50 – 17.10 Contributed IX: Borut Sluban, Jasmina Smailovic, Igor Mozetic and Stefano Battiston. Sentiment Leaning of Influential Communities in Social Networks

17.10 – 17.30 Invited II: one speaker from the CI2C project (confirmed, yet to be defined)

17.30   Planning Netonets Future Activities

Continue Reading

02 April 2015 ~ 0 Comments

A Marriage of Networks

My personal quest as ambassador of multiple networks at NetSci (previous episodes here and here) is continuing also this year. And, as every year, there are new exciting things coming along. This year, the usual satellite I organize is marrying another satellite. We are in fact merging our multiple networks with the Networks of Networks crowd. Networks of Networks is a society holding its own satellite at NetSci since quite a while. They are also interested in networks with multiple node and edge types, with more attention to infrastructure-flavored networks: computer networks, power grids, water infrastructure and so on. We are very excited to see what the impact between multiple networks and networks of networks, directed in particular by Antonio Scala and Gregorio D’Agostino, will generate.

The marriage is a promising one because, when talking about multiple networks and infrastructure, technical knowledge is dispersed among experts of different sectors – system operators from different industries (electric, gas, telecommunication, food chain, water supply, etc) – while researchers from different fields developed a number of different strategies to deal with these complex objects – from computer science to physics, from economics to humanities. To be exposed to these approaches and to confront one’s understanding of the potentialities of the analysis of multiple interdependent networks is key for the development of a common language to integrate the knowledge from all sectors. Complex Networks can be a common language for the needed federated approaches at both microscopic and macroscopic level. This satellite is here exactly to foster the development of such common language.

The usual practical information you might find useful:

  • The satellite will take place on June 2nd, 2015. It will be held, as usual, jointly with the other NetSci satellites. The location will be Zaragoza, Spain. The information about how to get there is included in the NetSci website.
  • The official website of the satellite is hosted by the Net-o-Nets parent website. The official page is this one. Information about the satellite is pretty bare-bones at the moment, but we’ll flesh it out in the following weeks.
  • We are open to submissions! You can send in your abstract and we’ll consider you for a contributed talk. The submission system goes through EasyChair, and this is the official link. The deadline for submission is April 19th, 2015 and we will notify you on April 29th.

Sadly, I will not be present in person to the event due to conflicting schedules. So I will not be able to write the usual report. I’ll leave you in the best hands possible. Submit something, and stop by in Zaragoza: you’ll find an exciting and stimulating crowd!

Continue Reading

26 June 2014 ~ 0 Comments

NetSci 2014 Report

NetSci, the top global conference about network science, never fails to be a tornado of ideas. Now that the dust has settled, I feel a bit easier to put this year’s thoughts on this post. Yes, this is yet another conference report by yours truly.

Let’s first get over the mandatory part of the report: an evaluation of the awesomeness of the Multiple Networks satellite I co-organized with my friends scattered around Europe. As said, this year’s edition was open to submissions and we received 17 of them. I think that, as a start, that is a good figure. Also, the attendance was more than satisfactory, and it appears scattered only because we got the largest room of the conference! Here’s proof!


The overall event was a great success. The talks were very interesting and we had a great unexpected bonus point. One of our keynotes, as you might remember, was Mason Porter. Well, the guy actually got the Erdos-Renyi prize this year! The Erdos-Renyi prize has been established in 2012 and it goes to outstanding young researchers in network science. Well, make a note of this: speaking at the Multiple Networks satellite will eventually get you some important awards. After all, everybody knows that correlation = causation.

My favorite satellite (besides the one I organized, obviously) continues to be the Arts, Humanities and Complex Networks symposium. This year it was a little bit tougher than usual, with a lot of qualitative stuff that not everybody can appreciate. However, their keynote by Lada Adamic was nothing short of outstanding. She is currently working at Facebook, a position that gives her a privileged vantage point over memes and viral events. You know that those things tickle my curiosity very strongly, and Lada’s work is really great. She presented her work, where she proves that meme evolution and mutation on Facebook follows very closely the same mechanics of evolution and mutation we find in the biological world. Good news for my old paper, which was heading in the same direction!

Which brings me to the main conference, because one of the best talks I attended was from Jon Kleinberg, who collaborated with Lada on another memes-meet-Facebook work. In that case, there is less good news for me. My research plan is to use meme content to predict virality. However, the Kleinberg-Adamic dream team showed that content is actually a very weak factor! (Here’s a blog post about it).

There is still hope, though. My way to deal with content is fundamentally different than theirs. Plus the problem they are studying is slightly different from mine: they are analyzing memes that are already going viral and they want to know how popular they will get. I’m more focused on knowing if the meme is going to be popular at all, and I’m not that concerned about whether everybody will know it or only a niche group.

Virality of content was a very hot topic this year, because there were two other fantastic talks about it. One was by Sinan Aral, and he talked about how much we are influenced by a post’s popularity when we read it. Controlling for content (and believe me when I say that Sinan is one of the best experiment designers out there), if we know that a post is popular we are more likely to upvote it. This is so true that Reddit itself decided, for some subreddits, to hide the post score for the first few hours, so that real good content will eventually flow to the top once the discussion is settled.

On top of that, also James Gleeson talked about a theoretical model that can account for the popularity distribution of memes. The model sounds simple. You just assume that a person has a box containing all the memes they saw in the past. With some probability, the person will either come up with something new or reshare a meme from their box. When resharing from the box, there is a memory effect for which more recent memes are more likely to be reshared. Whenever you share something, regardless if it is new or not, it ends up in your friend’s boxes. Even if it looks so simple, the actual solution of the model isn’t it at all and James is so good he defies belief. And, at the end of the day, everything works like a charm. Again, this does not bother me too much, because it only predicts the distribution of popularity, not which memes are going to be popular, a different problem.

Besides all this work meme popularity, there were other very interesting talks. I mention:

  • The very elegant talk by Chris Moore on community discovery, which also has the by-product of providing witty one liners for many occasions (for example “Physicists like to minimize functions because, you know, rocks fall”);
  • The nice talk by Frank Schweitzer on the role of active individuals in collaboration networks, who have the side effect of making the networks more unstable and prone to breaking apart (damn you, hyper-active people!);
  • The usual fun of the lighting talks (they could not call them ignite talks because of copyright issues). My favorite for this year was from Max Schich, with a really great panorama of the art market in London, Paris and Amsterdam from the Getty dataset. Aaron Clauset and Roberta Sinatra deserve to be mentioned too, with two great talks about climbing the greasy pole in academia (is it really worth it to shoot for big name universities? Short answer: no).

That’s it! You can see that also this year there was a lot to see and to think about. I am already looking forward for next year!

Continue Reading

22 May 2014 ~ 0 Comments

The NetSci Multiple Networks Menu

Friends, scientists, network fanatics, lend me your eyes: I come to announce the program of the Multiple Network Modeling, Analysis and Mining symposium, introduced some months ago on these pages. To give you a quick recap: this is a satellite event which will happen at the 2014 edition of NetSci, a major network science event of the year. The symposium will take place on Monday June 2nd, while the conference itself will start on June 4th and it will last until the end of the week. Differently from last year, we now have space for contributed talks and I like the program we were able to set up. So, I’ll boast about it here.

You can find the overview of the entire event on the official website, but let me give you the highlights.

We have four invited speakers: Frank Schweitzer, Renaud LambiotteNitesh Chawla and Mason Porter. They come from different backgrounds (System Design, Mathematics and Computer Science) which is a great plus for the event. They are going to:

  • Tackle the mathematical foundations of multiple networks;
  • Describe models for multiple networks;
  • Analyse them, both in the flavour of bipartite temporal social networks and in the extension of the classic link prediction problem. Usually in link prediction we are interested in evaluating the likelihood of seeing “a” connection between two nodes. Since in multiple networks there are different types of connections, we are also interested in predicting “which” connection we will observe.

As for the contributed talks, we have a pretty good team, including (but not limited to) works signed by David Lazer from Northeastern University, Juyong Park from KAIST, Eugene Stanley from Boston University and many more. We had such a positive reaction to our call for papers, that we had to increase the slots for contributed talks from 5 to 7 and still reject presentations that we really wanted to see. Among my favourites works there are:

  • Multiple network applications to study the productivity of countries and predicting their growth;
  • The study of evolution of different relations among almost 2000 students from 14 US universities;
  • A network-based approach for ranking the performances of sport teams;
  • Novel way to classify nodes in complex networks where multiple different relations are present;
  • … and more!

For completeness, here’s the detailed schedule, I hope to see many of you there!

Session I

9.00 – 9.30 Registration / Set Up
9.30 – 9.50 Introduction: Welcome from the organizers, presentation of the program
9.50 – 10.30 Keynote I: Frank Schweitzer, Professor for Systems Design at ETH Zurich
Analysing temporal bipartite social networks
10.30- 11.00 Coffee Break

Session II

11.00 – 11.40 Keynote II: Renaud Lambiotte, Associate Professor, Department of Mathematics at University of Namur
Non-Markovian Models of Networked Systems
11.40 – 12.00 Daniel Romero, Nina Mishra and Panayiotis Tsaparas
Estimating the Relative Utility of Networks for Predicting User Activities
12.00- 13.30 Lunch

Session III

13.30 – 14.10 Keynote III: Nitesh Chawla, Associate Professor, Department of Computer Science & Engineering at the University of Notre Dame
Predicting links in heterogeneous social networks
14.10 – 14.30 Katherine Ognyanova, David Lazer, Michael Neblo, Brian Rubineau and William Minozzi
Ties that bind across contexts: personality and the evolution of multiplex networks
14.30 – 14.50 Neave O’Clery
A Multi-slice Approach to Understanding the Evolution of Industrial Complexity and Growth
14.50 – 15.30 Coffee Break

Session IV

15.30 – 16.10 Keynote IV: Mason Porter, Associate Professor at the Oxford Centre for Industrial and Applied Mathematics
Mathematical Formulation of Multilayer Networks
16.10 – 16.30 Seungkyu Shin, Sebastian Ahnert and Juyong Park
Degree-Neutralizing Weighted Random Walk Ranking in Competition Networks
16.30 – 16.50 Tomasz Kajdanowicz, Adrian Popiel, Marcin Kulisiewiecz, Przemysław Kazienko and Bolesław Szymański
Node classification in multiplex networks
16.50 – 17.10 Francesco Sorrentino
Stability of the synchronous solutions for networks with connections of different types
17.10 – 17.30 Andreas Joseph, Irena Vodenska, Eugene Stanley and Guangron Chen
MLR Fit-Networks: Global Balance of Payments

Conclusion and final announcements

17.30 – 18.00

Continue Reading

25 February 2014 ~ 0 Comments

It’s happening! (Again)

You know that I am a guy deeply involved in multiple networks, networks containing different types of relations. You probably also remember that last year I organized, with Matteo Magnani, Luca Rossi, Dino Pedreschi, Guido Caldarelli and Przemyslaw Kazienko, a symposium on such a fascinating mathematical model and its applications (my report on it). Well: it is going to happen again at the 2014 edition of NetSci.

Some things changed since last year. Let me start from the most important. This year we are open to contributed talks! Last year the speakers where invitation-only: we were just starting and we wanted to understand what kind of crowd we had. The response was positive for the event and negative for the poor guy (me) who had to find extra chairs to accommodate the larger-than-expected bunch of people who showed up. So, choose your best work on multiple (multiplex, multidimensional, multilayer, multirelational… whatever!) networks and send a 300-word abstract and a figure here: https://www.easychair.org/conferences/?conf=mnam2014. You have time until April 14th, and you will receive notification of acceptance in two weeks, April 28th.

We are still going to have exciting keynotes, of course. So far, the first confirmed speaker is Renaud Lambiotte. If you read this blog, chances are that you are already familiar with the outstanding work he is doing in network science.


The date of the event didn’t change, it is still the first week of June (UPDATE: the exact day the satellite will take place is June 2nd, for the entire day). The location, of course, did: it is going to happen in Berkeley California, at the Claremont Hotel and the Clark Kerr Campus of the University of California. We go where NetSci goes, and with a reason: NetSci is the premier venue if you are interested in network science. And we want to play with the coolest kids, don’t we?

Two other things did not change and are worth remembering. First, participation is free of charge. We are interested in your brains, not your wallets. (UPDATE: Apparently, even if you are just attending this satellite, NetSci’s organizers require you to register anyway. Rates and information are here. Early registration is April 4th. Here, we are still interested just in your brains, though :) ). Second, we are still asking you to tell us if you are planning to come to the event. It is mostly a selfish maneuver: I want to limit my quests in finding extra chairs to the minimum. For this reason, we set up this handy and quick Google form for you.

So, don’t forget to send us an abstract. And see you in just a couple of months in Berkeley!

Continue Reading