Seminar of Computer Networks: Online Social Networks

Academic Year 2008 / 2009

Online social networks have become a major driving phenomena on the web since the Internet has expanded as to include users and their social systems in its description and operation. Internet has developed from a communication medium and information sharing devise into a platform enabling a wide range of new social activities and applications. There is a growing number of highly-popular user-centric applications in Internet that rely on social networks for mining and filtering information, for providing recommendations, tags, annotations, as well as for ranking of documents and services. Successfully striking examples are collaborative recommendation systems (e.g., Amazon for books and Netflix for DVDs), folksonomies - systems of collaborative social tagging - (e.g., Citeulike, Delicious, Flickr and Youtube), cooperative systems for building repositories of information as Wikipedia, systems of social networking (e.g., myspace, Facebook) and forum of discussion and opinion formation (e.g., blogs and Web communities). In this course we will present the design principles and the main structural properties of on-line social networks and some of the applications that rely on the social network paradigm.


17/6/2009: More details have been added about project 4.

18/5/2009: The second set of homeworks and the projects are out.

6/5/2009: The solution of the first homework are out.

15/4/2009: There will be a rescheduling in May. The classes of May 6, 13, and 20 will move to Mondays May 4, 11, and 18, from 10:00-14:00. The class of Prof. Vitaletti will move from Monday to Wednesday from 12:00-15:30 at l'Aula Magna (1st floor).

1/4/2009: The first homework is out. It is due on April 29, before the class.

You can do the homeworks in groups of 3 students or less. If you are trying to find a group or people, send an email to Aris to try to match you.


Prof. Stefano Lenardi, Sapienza University of Rome
Dr. Aris Anagnostopoulos, Sapienza University of Rome, email:
Dr. Debora Donato, Yahoo! Reasearch Barcelona

Guest Lecturers
Prof. Jared Saia, University of New Mexico
Navin Rustagi, University of New Mexico
Prof. Guido Caldarelli, National Research Counsil

When and Where

When: Wednesday 12.00-1.30 and 2.00-3.30
Where: Via Ariosto 25, Aula B1

Office Hours

Aris: Monday, 2pm-4pm, office B118. If you have classes at this time we can arrange by email.


There does not exist a book for the class material. We will post the slides and maybe some notes for some of the lectures.


We will cover some of the following topics, and maybe a few more to be decided:

Homeworks, Exams

We will have 3 homework sets and a final project. You will work in groups of 3 for homeworks and for the project.
For the project you will have two options:
Homework 1           Out: 1/4/2009         Due: 29/4/2009, before the class.     [Solutions]
Homework 2           Out: 1/4/2009         Due: 10/6/2009.
Proceedings of WWW 2008, KDD 2008, and WWW 2008.


Class notes (last updated 15/4/2009)

11/3/2009: Basic combinatorics
Basic matirial for counting permutations and combinations, binomial coefficients, etc.

11/3/2009: Introduction to probability
Here you can find a brief introduction to probability. Make sure that you understand all the material.

11/3/2009: Random variables
This describes random variable, expectation, variance, and other related topics. We will work mostly with discrete random variables but you should know the basics for the continuous ones.

11/3/2009: Main distribution functions
It describes the main types of distributions. Definitely understand Section 5.1 and you can study the rest when we do them in the class


4/3/2009: Lecture 1, 4/3/2009: Introduction, structural properties, Erdos-Renyi random-graph model

16/3/2009: Lecture 2, Probability, 7/3/2009: Basic discrete probability, random variables, expectation

1/4/2009: Byzantine Aggreement, 25/3/2009, by Prof. Jared Saia

1/4/2009: Complex Networks, 1/4/2009, by Prof. Guido Caldarelli

10/4/2009: Epidemics, 8/4/2009: Viruses, Models, Influence/correlation

4/5/2009: Graph Mining, 22/4/2009

4/5/2009: Reputation Management, 29/4/2009

25/5/2009: An Introduction to Social Media

25/5/2009: Expertise and Quality in Online Social Community

25/5/2009: Taxonomies, Folksonomies and Tagging: How Social Bookmarking can improve Web search

25/5/2009: Context Search

27/5/2009: Online Communities