Takayuki Hiraoka
Complex Systems Scientist / Network Scientist
Postdoc at Aalto University
I am a complex systems scientist, working mainly in the field of network science. My current research focuses on:
Modeling epidemics and interventions
Networks of human populations (both longitudinal and cross-sectional)
However, I'm interested in many other things! In the past, I have worked on:
non-Markovian temporal processes
temporal networks
I am currently a postdoctoral researcher at Aalto University in Finland.
What is complex systems? What is network science?
Complex systems broadly refer to the systems in which the interaction between many elements leads to the emergence of unexpected collective behaviors. Examples can be found in every corner of our lives on every scale: human societies, cells, brains, organisms, ecosystems, evolution, epidemics, languages, culture and norms, mobility and migration, information and communication systems, cities and transportation systems, infrastructure, democracy and politics, market and economic systems, climate and earthquakes—so yes, pretty much anything that is difficult to model from first principles. As a complex systems researcher, I prefer to look for commonalities and connections between these seemingly unrelated areas rather than studying each one in isolation.
Network science is the collection of studies that models systems as networks—a mathematical object consisting of nodes and links. The nodes represent the components of the system, and the links represent how they interact with each other. This simplification and abstraction allows us to focus on how elements are connected and what the connection patterns mean for the behavior of the system. Although a relatively new discipline, network science has become a cornerstone of complex systems research because it provides a powerful toolkit for studying diverse systems.
Updates
[2024-04-25] I will give a talk at CompleNet 2024 in Exeter, UK:
The strength and weakness of disease-induced herd immunity.[2023-09-24] I gave an online talk at the International Symposium and Workshop “Compiling GIS for Integrating Linguistic and Non-linguistic Information” organized by the National Museum of Ethnology, Japan:
Geospatial Analysis of Toponyms in Geotagged Tweets.[2023-07-12] I gave a talk at NetSci 2023 in Vienna, Austria:
Strength and weakness of disease-induced herd immunity.[2023-07-10] We have a new preprint on arXiv:
The strength and weakness of disease-induced herd immunity.[2022-12-05] Our paper was published in Travel Behaviour and Society:
Estimating inter-regional mobility during disruption: Comparing and combining different data sources.[2022-10-18] I gave a talk at the Conference on Complex Systems 2022 in Palma de Mallorca, Spain:
Herd immunity and epidemic size in networks with vaccination homophily.[2022-05-12] Our paper was published in Physical Review E:
Herd immunity and epidemic size in networks with vaccination homophily.[2022-04-07] Our paper was published in PLoS Computational Biology:
Adaptive and optimized COVID-19 vaccination strategies across geographical regions and age groups.[2021-10-25] I gave a talk at the Conference on Complex Systems 2021 in Lyon, France:
Vaccination strategies for minimizing the number of deaths from emerging diseases.[2021-07-26] Our paper was published in Physical Review E:
Individual-driven versus interaction-driven burstiness in human dynamics: The case of Wikipedia edit history.[2021-07-08] I gave an online talk at Networks 2021:
Vaccination strategies for minimizing the number of deaths from emerging diseases.[2020-09-25] I gave an online talk at NetSci 2020:
Burst-tree decomposition of time series reveals the structure of temporal correlations.[2020-07-22] Our paper was published in Scientific Reports:
Burst-tree decomposition of time series reveals the structure of temporal correlations.[2020-05-24] Our paper was published in Northeast Journal of Complex Systems (NEJCS):
Waiting-Time Paradox in 1922.[2020-04-24] Our paper was published in Physical Review Research:
Modeling temporal networks with bursty activity patterns of nodes and links.[2020-02-01] I started working as a postdoctoral researcher at Aalto University, Finland.
[2020-01-20] I gave a talk at NetSci-X 2020 in Tokyo, Japan:
Genealogical network analysis of social group evolution.