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...

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...

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...

Although there are extensive researches on the behavior of the world currency network, the complexity of the Asian regional currency system is not well understood regardless of its importance. Using daily exchange rates this paper examines exchange rate co-movements in the region before and...

We study human dynamics by analyzing Linux history files. The goodness-of-fit test shows that most of the collected datasets belong to the universality class suggested in the literature by a variable-length queuing process based on priority. In order to check the validity of this model, we...

We investigate course registration data of 18 semesters at a Korean University to portray the time evolution of students’ positions in the network of fellow students. Apart from being a study of the social positions of students, the present work is also an example of how large-scale, time...

We empirically study various network properties of an online community. The numbers of articles written by each user to the bulletin boards of each of the others are used to construct the directed and weighted network B, and gifting behaviors among users are also kept track of, to build the...

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...

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,...