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06 January 2021 ~ 1 Comment

The Atlas for the Aspiring Network Scientist

In the past two years, I’ve been working on a textbook for the Network Analysis class I teach at ITU. I’m glad to say that the book is now of passable enough quality to be considered in version 1.0 and so I’m putting it out for anyone to read for free. It appeared on arXiV yesterday. It is available for download on its official website, which contains the solutions to the exercises in the book. Ladies and gentlemen, I present you The Atlas for the Aspiring Network Scientist.

As you might know, there are dozens of awesome network science books. I cannot link them all here, but they are cited in my atlas’ introduction. So why do we need a new one? To explain why the atlas is special, the best way is to talk about the defects of the book, rather than its strengths.

The first distinctive characteristic is that it aims at being broad, not deep. As the title suggests, I wanted this to be an atlas. An atlas is a pointer to the things you need to know, rather than a deep explanation of those things. In the book, I never get tired of pointing out the resources you need to actually understand the nitty-gritty details. When you stumble on a chapter on something you’re familiar with, you’ll probably have the feeling that you know so much more than me — which is true. However, that’s the price to pay if I want to include topics from the Hitting Time Matrix to the Kronecker graph model, from network measurement error to graph embedding techniques. No book I know includes all of these concepts.

The second issue derives from the first: this is a profoundly personal journey of eleven years through network science. No one can, in such a short time, master all the topics I include. Thus there’s an uneven balance: some methods are explained in detail because they’re part of my everyday work. And others are far from my area of expertise. Rather than hiding such a defect, the book wears it on its sleeve. I prefer to include everything I can even if I’m not an expert on it, because the first priority is to let people know that something exists. If I were to wait until I was an expert R programmer before advising you to use iGraph, the book would not exist. If I were to leave out iGraph because I’m not good at it, it would make the book weaker — and give the impression of dishonesty, like the classic Pythonist who ignores R because “it’s the opposing team”.

Finally, the book reads more like a post on this blog than an academic textbook. I use a colorful style and plenty of humor. This is partially as a result of the second point, since the humor is mostly self-deprecating about my limits — for instance, the stabs I take at R are intended as light-hearted jest. In general, I want to avoid being excessively dry and have the readers fall asleep at page 20. This is a risky move, because humor is subjective and heavily culture-dependent. People have been and will be put off by this. If you think I cross the line somewhere in the book, feel free to point that out and ask me to consider your concerns. If, instead, you think that humor in general has no place in academia, then I disagree, but there are plenty alternatives, so you can safely ignore my book.

Given all of the above, it is no surprise that the atlas is imperfect and many things need to be fixed. Trust me that the first draft was significantly worse in all respects. The credit for catching my mistakes goes to my peer reviewers. Every one of their comments was awesome, and every one of the remaining mistakes are only my fault for being unable to address the issues properly. Chief among the reviewers was Aaron Clauset, who read (almost) the entire thing. The others* still donated their time and expertise for free, some of them only asked me to highlight worthwhile charities such as TechWomen and Evidence Action in return.

Given all the errors that remain, consider this a v1.0 of a continuous effort. There are many things to improve: language, concepts, references, figures. Please contact me with any comments. The PDF on the website will reflect changes as soon as is humanely possible. Before I put v1.1 on arXiV, I’ll wait to have a critical mass of changes — I expect to have it maybe for mid to late February.

I also plan to have interactive figures on the website in the future. Version 1.0 was all financed using my research money and time. For the future, I will need some support to do this in my free time. If you feel like encouraging this effort, you can consider becoming a patron on Patreon. A print-on-demand version will be available soon (link will follow), so you could also consider ordering a physical copy — I’ll make 70 juicy cents of profit for every unit sold, because I’m a seasoned capitalist who really knows how to get his money’s worth for two years of labor.

I poured my heart in this. I really hope you’ll enjoy it.

* Special thanks go to Andres Gomez-Lievano. The other peer reviewers are, in alphabetical order: Alexey Medvedev, Andrea Tagarelli, Charlie Brummitt, Ciro Cattuto, Clara Vandeweerdt, Fred Morstatter, Giulio Rossetti, Gourab Ghoshal, Isabel Meirelles, Laura Alessandretti, Luca Rossi, Mariano Beguerisse, Marta Sales-Pardo, Matte Hartog, Petter Holme, Renaud Lambiotte, Roberta Sinatra, Yong-Yeol Ahn, and Yu-Ru Lin.

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07 September 2020 ~ 0 Comments

Media, Special Issues, & Personal Growth

A quick and unusual post for this blog to keep you up to date with what happened in my summer.

First, I’m happy to report that my paper on the effect of business travels on economic growth — which I describe here — is generating a fair amount of buzz. You can read the excellent summary written by Ricardo on Project Syndicate, or my own “Behind the paper” version. If podcasts are your thing, we got you covered. And I’ll present it at the Copenhagen Fintech on September 16th.

Second, I’m teaming up with the most excellent prof. Morgan Frank from the University of Pittsburgh to edit a special issue for the journal Frontiers in Big Data Networks. We called the special issue “Complex Networks and Economics” and we intend it to be a safe haven for all of you advancing our understanding of the complex systems that compose our global, regional, and local economy. You can read more at the official page of the journal (linked above), or in this post I wrote for my NERDS research group. Consider submitting!

And, finally, one last bit of shameless self-celebration. Something new happened on the header of this blog:

Yai me! I’m a real associate grownup now! (Actually, effective on October 1st. So I still have time to mess this up)

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09 July 2018 ~ 0 Comments

Small Changes, Big Changes

A very quick note to point out a tiny change in my website. The top banner that always welcomes you to the home page of this blog has been changed. It is an insignificant text difference, which hides a slightly larger one in my life. I’ve changed jobs! After six years of postdoc fellowship, I decided I had enough of it and made the big jump: I’m now an assistant professor. I’ve also decided to hop to a different side of the Atlantic pond. I left the United States and decided to make a home of Denmark. My new affiliation is the IT University of Copenhagen.

There are a few more things changing in the next weeks/months. The most important one is that I’ll start teaching the class on Network Analysis. This is a class for the first semester of the second year in the Bachelor program of Data Science. This Data Science ship is captained by the amazing Natalie Schluter. I’m not alone in this adventure: my friend Luca Rossi will be co-teaching with me this year. I look forward to give my contribution to the data science and network science development of the Copenhagen area.

This means that you’ll see soon a new tab in the top menu of the blog: “Teaching”. I’ll use it to host the materials from the classes I’ll be teaching: slides, additional texts, etc. This should allow you to get a hint of my lecturing style and — why not? — see if you can learn something new.

If you are in the Copenhagen area and you think you’d like to talk a bit of network business, you can probably find me at my new shiny office, while I try to hide behind the largest monitors I could find. The office number is 4E04, meaning that I’m at the 4th floor, wing E, office 4 (on the right).

Interesting times ahead!

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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!

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13 October 2014 ~ 1 Comment

In the Media

Another quick pause this month from my written blabbering about my research. Because it is time for some spoken blabbering about my research!

First and foremost: I was invited to register a 100-seconds audio segment for the Academic Minute. The Academic Minute is a radio program of the WAMC Northeast Public Radio that gives to scholars around the world a chance for a very brief presentation of their work. My segment is going to air tomorrow at 7:34 AM (Eastern time) and, if you do not want to get up early, also at 3:56 PM. The segment is going to be about my work on memetics. If you do not have a radio (duh) you can live stream from their website. The live stream might work also if you are not in the US. but I haven’t really checked. However, once it’s done, you can probably download the podcast (although I am not really sure why somebody would get into so much trouble just to listen to my delirious thoughts for 100 seconds). A big thanks to Matthew Pryce, who organizes the program and was so kind to invite me for a segment.

That is not the only way to hear about my work on memes. The paper that I recently published in Scientific Reports was also the subject of a lighting talk I gave at the Digital Umanities Forum at Kansas University (I talked about the Forum a couple of weeks ago). Brian Rosenblum was kind enough to upload a video of my talk to Youtube. So here it is:

One speaker had to cancel her presentation, and people were invited to fill the gap. So excuse my lack of fluency, but I didn’t know I was going to present until the day itself! This is it for now, I promise that I’ll write something more about this paper in the future.

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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: 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!

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21 March 2013 ~ 2 Comments

Multidimensional Networks @ NetSci!

This month, I am interrupting the sequence of posts discussing my papers for a shameless self-promotion – after all, this entire website is shameless self-promotion, so I don’t see a problem in what I’m doing. Some months ago, I discussed my work on multidimensional networks, networks that include different kinds of relations at the same time. The whole point of the post was that these are different animals than traditional complex networks, and thus they require new tools and a new mindset.

So I asked myself: “What is the best way to create this new sensibility in the network community?”. I also asked a bunch of other great people, in no particular order: Matteo Magnani, Luca Rossi, Dino Pedreschi, Guido Caldarelli and Przemyslaw Kazienko. The result was the topic of today’s post: a symposium in the 2013 edition of the NetSci conference!

NetSci is a great venue for network people. From their website:

“The conference focuses on interdisciplinary research on networks from various disciplines such as economy, biology, medicine, or sociology, and aims to bring new network analytic methods from physics, computer science, math, or statistics to the attention of a large and diverse audience.”

This year, NetSci will take place in Copenhagen and you should check out a number of reasons for attending. One of those reasons is our symposium, called “Multiple Network Modeling, Analysis and Mining“. You can check important information about attending the symposium in the official event webpage: Here are the three main highlights:

  • It is an excellent occasion to learn more about multidimensional networks, a model that can help understand the complex interplay between the different relationships we establish every day (friendship, collaboration, club membership, …), better than everything else has been done before;
  • We still have to finalize our speaker list, but it will be of very high quality and will include Jiawei Han, Lei Tang, Renaud Lambiotte and others;
  • Symposium attendance is free! And there will be free food! Woo-hoo! Just sign up in the official Google Doc.

Don’t take my word on the first point and check out the publications we refer to in our webpage. Here, following the above mentioned shameless self-promotion, I’ll list the papers on the subject written by yours truly:

If you find all of this interesting, I definitely hope to see you in Copenhagen this June!

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03 August 2012 ~ 0 Comments

Hello World!

I tried to find a smart title for my first post here, but I found the default WordPress option very suitable for my computer science-ish background.

Why am I starting this blog? Well, I firmly believe that science should be connected to everyday life. I also believe that what I am doing may be interesting and useful to improve the above mentioned everyday life. Finally, I think that to read one of my papers directly will provide little or no contribution to the community, given my total inability to write scientifically (and even non-scientifically) and the obscure link between an algorithm that I have developed and the science that makes your refrigerator or iPad work day after day.

So, here we are: the idea of this blog is to provide, hopefully, some interesting content. The fixed sections of the website are for the people who want to read directly the published paper, or to download the datasets and/or the algorithms I have developed. These posts, instead, will provide quick, dirty and informal descriptions of my papers and of everything I find interesting and worth noticing. If you ever read a scientific paper and, at the end, you found yourself asking “So what?”, the blog is the place to find the answer. At least for my papers.

The updates are meant to be regular, but don’t expect them to be frequent! If I spend all my working hours writing this blog I’ll run out of quality material. Plus I may get fired, and that’s not nice.

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