The family name distribution in Korea is investigated in comparison with previous studies in other countries. In Korea, both the family name and its birthplace, where the ancestor of the family originated, are commonly used to distinguish one family name from the others. The family name...

To find out the role of the wiring cost in the organization of the neuronal network of the nematode Caenorhabditis elegans, we build the spatial neuronal map of C. elegans based on geometrical positions of neurons. We show that the number of interneuronal connections of the Euclidean length d...

Threshold models try to explain the consequences of social influence like the spread of fads and opinions. Along with models of epidemics, they constitute a major theoretical framework of social spreading processes. In threshold models on static networks, an individual changes her state if a...

Network marketing has been proposed and used as a way to spread the product information to consumers through social connections. We extend the previous game model of the network marketing on a small-world tree network and propose two games: In the first model with the bounded rationality, each...

We use a cellular automata approach to numerically investigate traffic flow patterns on a single lane. The free-flow phase (F), the synchronized phase (S), and the jam phase (J) are observed and the transitions among them are studied as the vehicular density ρ is slowly varied. If ρ is...

Recently there has been a tremendous interest in models of networks with a power-law distribution of degree—so-called “scale-free networks.” It has been observed that such networks, normally, have extremely short path-lengths, scaling logarithmically or slower with system size. As an...

We statistically verify the Hardy–Weinberg principle in genetics by investigating the independence of ABO-blood types of married couples. The allelic frequencies derived from the phenotypic frequencies in ethnic groups via the Hardy–Weinberg principle are used to define a genetic distance...

We investigate a dynamic model of network marketing in a small-world network structure artificially constructed similarly to the Watts–Strogatz network model. Different from the traditional marketing, consumers can also play the role of the manufacturer's selling agents in network marketing,...

Most research of online communication focuses on modes of communication that are either open (like forums, bulletin boards, Twitter, etc.) or direct (like e-mails). In this work, we study a dataset that has both types of communication channels. We relate our findings to theories of social...

The weighted and directed network of countries based on the number of overseas banks is analyzed in terms of its fragility to the banking crisis of one country. We use two different models to describe transmission of shocks, one local and the other global. Depending on the original source of the...