Two variants of the friendship paradox: The condition for inequality between them arxiv.org/abs/2511.06176 a small experimental scientific communication project, encouraged by @socph.bsky.social

중간고사 문제 출제를 계기로 다시 보기 시작했고, 궁금증을 해결했지만 논문거리는 아닌 것 같아서 이 정도로 남김 ... 을 ChatGPT가 이 정도로 확장해 줌 ... 😶

친구 역설 또는 우정 역설 (friendship paradox) 에 대해 예전부터 갖고 있었던 의문이 있었는데, ChatGPT의 도움으로 해결한 듯 하다. 1. 결과물: drive.google.com/file/d/1GRSu... 2. 배경 설명: drive.google.com/file/d/1Uqu1... 이런 간단한 일을 *빠르기* 처리하기엔 좋은 듯 함.

Accepted for publication in Chaos! @takayukihir.bsky.social

Attending the KPS fall meeting in Gwangju, Korea

Our paper “Regional disparities in the distribution of public and private healthcare facilities in South Korea” has been published in the international journal PLOS ONE 🎉 (lnkd.in/gMPnhkdC) Special thanks to our undergraduate co-author (3rd year student) for contributing to this meaningful study.

I just learned that Asia-Pacific Summer School and Conference on Networks and Complex Systems will be held next year at NTU, Singapore. Please check out the official website: apcncs2026.github.io

I just copied the poster of the workshop, which looks interesting.

Now attending the RHINO 2025 in Pukyong National University in Busan with participants mostly from Korea and Japan.

Our new preprint with @takayukihir.bsky.social is out in arXiv: Takayuki Hiraoka‬ and Hang-Hyun Jo, Hierarchical organization of bursty trains in event sequences, arxiv.org/abs/2508.18281

I submitted my manuscript to the arXiv one week ago, which is still "on hold", and didn't get any message from the arXiv since then. Should I wait longer or take any action?

Is this the first journal containing the term "social physics"? In any case, I'm excited to see that such journal has been finally started.

🌐 Journal of Social Physics now accepting submissions exploring the sociophysics, econophysics, and overlaps with computational social science. Share your research! #CallForPapers #SocialPhysics #ComplexSystems sciltp.com/journals/jsp

Yet another kind of friendship paradox, an imposter paradox?

Our new preprint is out in arXiv: Copula-based analytical results of horizontal visibility graphs for correlated time series arxiv.org/abs/2508.08934 This is from the collaboration with my undergraduate student Jeong-Min Lee.

Attending the summer school on nonlinear dynamics and chaos at KIAS

I posted a short article to my blog: brunch.co.kr/@socph/21 . The title is "fixed points and fate". To be precise, the fate of x(t) following the differential equation dx/dt=f(x,r) is determined by the parameter r.

Wow cool!

Our new preprint is out! Hyun-Woo Lee, Gerardo Iñiguez @iniguezg.bsky.social Hang-Hyun Jo, Hye Jin Park @hyejinpark.bsky.social "Ranking dynamics in movies and music" arxiv.org/abs/2506.21944

We also showed that the use of toponyms decays as a power law outside the area they represent. If you are interested in knowing more, read on here: doi.org/10.1371/jour...

We found that toponyms show spatial specificity in their occurrence, unlike many common nouns. Interestingly, toponyms and common nouns describing places (e.g., “park”) behave differently from other common nouns (e.g., “music”) and toponyms referring to places outside the observation area.

However, quantitative studies of toponyms have been scarce. In our new article in PLOS One, Takashi Kirimura, Naoya Fujiwara and I tried to address this gap by using a dataset of 400 million geotagged Twitter posts to study the association between toponyms and geography.

Spatial cognition is vital for all animals. Humans, in particular, use cartographic knowledge and language to understand the environment beyond what we directly experience. Place names (toponyms) play a key role in this cognitive process as they reflect how we mentally structure geographical space.

Our paper has been finally published in Physica D! See www.sciencedirect.com/science/arti...

PLOS ONE: Homophilic organization of egocentric communities in ICT services https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0325187

It reminds me of my first encounter with the topic of chaos in 1994, when I read the James Gleick's book "Chaos" in my high school. I was deeply fascinated by the concept of "sensitive dependence on initial conditions" because everything around me seemed very confusing.

저도 영광스럽게 번역에 참여할 수 있었던, 스티븐 스트로가츠 @stevenstrogatz.com 교수님의 명저 '비선형 동역학과 카오스' 한국어판이 6월 23일 출간될 예정입니다.

www.complexity.kr?p=1322 I'm pleased to join the 2025 KACS-KENTECH Summer School on Complex Systems as a lecturer with other 7 lecturers. This year we study the Korean translation of the famous book "Nonlinear Dynamics and Chaos" by Steven Strogatz. All lectures are given in Korean too.

www.iccs-meeting.org/iccs2025/asi... In coming July I'll attend the Asian Network of Complexity Scientists Workshop as a part of the 25th ICCS to be held in Singapore.

Our paper has been finally published in PLOS ONE! See doi.org/10.1371/jour...

Now published in Physical Review E, see doi.org/10.1103/Phys...

Looks like a great opportunity for early-career scientists!

The deadline for abstract submission is 23 May.

Hi, I am seeking a postdoctoral position in statistical physics. If you know of any open positions, please let me know. Thank you!

GREAT honor to be invited to talk here! :)

We're organizing the "APCTP Workshop on the Roles of Heterogeneity in Nonequilibrium (RHINO 2025)"; the workshop will be held from 29 August to 1 September 2025 in Pukyong National University (PKNU), Busan, Korea. www.apctp.org/theme/d/html...

www.kps.or.kr/content/comm... 🎉🎉🎉

BREAKING NEWS - South Korean President Yoon Suk Yeol REMOVED from office by the court's unanimous decision www.washingtonpost.com/world/2025/0...

Open postdoc position at @ceu-dnds.bsky.social in Vienna in the Computational Human Dynamics Lab of @martonkarsai.bsky.social on inequalities in 15-minutes cities in collaboration with www.dut-coline.org. Check it out: careers.ceu.edu/job/Vienna-P... @ic2s2.bsky.social @netscisociety.bsky.social

Our new paper is out in arXiv: Tibebe Birhanu, Hang-Hyun Jo, "Maximum likelihood estimation of burst-merging kernels for bursty time series" arxiv.org/abs/2503.14861

📢 New paper out! "Quantifying collective attention and fan engagement: A case study of the Japanese professional baseball league" w/ @soramame0518.bsky.social et al. link.springer.com/article/10.1...

The Complex Systems Society has taken a stance! Read about the Manifesto on the Publishing and Evaluation Systems at: cssociety.org/about/manife... #CSSManifesto

My following paper was desk-rejected from PRE because it doesn't "fall within the main interests of our readers". Since when did PRE readers lose the interest in autocorrelation function analysis???

arxiv.org/abs/2502.17841 new preprint with my outstanding graduate student & colleague!

The call for a postdoc position in Network Science / Computational Social Science / Social Data Science funded by the EU grant on Networks and the Rule of Law (NET-ROL) IS STILL OPEN! careers.ceu.edu/job/Vienna-P...

Our new paper is out on arXiv: Min-ho Yu and Hang-Hyun Jo, Analysis of the autocorrelation function for time series with higher-order temporal correlations: An exponential case arxiv.org/abs/2502.11043

The Welsh told the Saxons this hill was called "pen" (meaning "hill"). The Saxons added their word for hill, "tor," and called it Torpen (hill hill). Later the Norse added their world for hill. So it became Torpen Haugr (Hill Hill Hill). Now the English call it Torpenhow Hill (Hill Hill Hill Hill)

Burst-tree structure and higher-order temporal correlations link.aps.org/doi/10.1103/...

East Asia representatives at #NetSciX2025!