Download Report of the visit to Aalto University Visiting scientist: Prof. Hang

Report of the visit to Aalto University
Visiting scientist: Prof. Hang-Hyun Jo, https://sites.google.com/site/h2jo23/
Home institution: Pohang University of Science and Technology, Republic of Korea
Host: Prof. Kimmo Kaski
Visiting period: February and July 2015
Scientific achievements:
During two visits to Aalto University in the year 2015, I conducted an ongoing research project with
Prof. Kimmo Kaski as well as with Prof. Janos Kertesz from CEU in Hungary, Prof. Janos Torok
from BMI in Hungary, and Dr. Yohsuke Murase from RIKEN in Japan. Our collaborating project
aims to understand and model the structural and dynamical aspects of the real social networks in
terms of complexity sciences, such as computational social science.
One of the simplest yet realistic social network models was studied by Kumpula et al. in 2007. We
have developed this model to understand the role of relationship fading and breakup in the
formation of social networks, leading to the publication:
Y. Murase, H.-H. Jo, J. Torok, J. Kertesz, and K. Kaski, Modeling the Role of Relationship Fading
and Breakup in Social Network Formation, PLoS ONE 10, e0133005 (2015).
Stemmed from this line of research, we have raised the important question of what the real social
network at the societal level looks like. There exist common features of social networks from
various datasets, which we call “stylized facts” in social networks. Most empirical analyses indicate
that individuals with only one neighbor (or friend, family member, etc.) dominate the population,
which is however not consistent with our common sense that most people have at least several
neighbors. We devised a sampling method to show that such biases could be attributed to the
sampling not to the real society. We submitted our manuscript that is available in online repository:
J. Torok, Y. Murase, H.-H. Jo, J. Kertesz, and K. Kaski, What does Big Data tell? Sampling the
social network by communication channels [arXiv:1511.08749]