We study the temporal evolutions of three stock markets; Standard and Poor's 500 index, Nikkei 225 Stock Average, and the Korea Composite Stock Price Index. We observe that the probability density function of the log-return has a fat tail but the tail index has been increasing continuously in...

We study the temporal evolution of the market efficiency in the stock markets using the complexity, entropy density, standard deviation, autocorrelation function, and probability distribution of the log return for Standard and Poor's 500 (S&P 500), Nikkei stock average index, and Korean...

Using the price change and the log return of 10 stock market indices, we examine the temporal evolution of the time scale. The 10 stock markets had similar properties. Their log-return time series had patterns and long-range correlations until the mid-1990s. In the 2000s, however, the long-range...

We review recent progress in generalized-ensemble simulations of proteins. Focusing on the formation of secondary structure, we show how these techniques can lead to a deeper understanding of the folding mechanism in proteins.

We propose a novel approach for estimating the similarity between the trends of two time series, which has been an important problem in the fields of finance, economics and econophysics. We introduce the exit-time correlation (EC) to measure this similarity based on the exit-time method recently...

We investigate the grouping property of industry sectors in the complex network based on stock data for US and Korean stock markets. The complex networks are constructed by the minimal spanning tree (MST). We propose a novel approach based on the shortest path length (SPL) between stocks to...

In this paper, we investigate the effect of fast traders in continuous double action markets using agent-based modeling. We consider two agent types, such as fast and slow traders, by preference of investment time in a high-risk environment. Additionally, the order aggressiveness of agents with...

In financial market, one of complex systems, there is highly nonlinear interaction between heterogeneous traders. Due to this nonlinear interaction, emergent behavior, which is so called ‘stylized facts' occurs in financial market. To understand impact of interaction between heterogeneous...