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Open source software (OSS) has become indispensable to our society. The success of OSS depends on the participation of a large number of developers or maintainers (contributors). Shedding light on the mechanisms of their participation has been an important academic and practical matter. One aspect to decide participation is the future prospects of a project. However, the causal mechanism behind participation has yet to be studied exhaustively and remains unclear. In this study, we used cryptocurrency projects, many of them were developed on GitHub, to better understand this mechanism. Both GitHub and cryptocurrencies are highly transparent, i.e., information is fully disclosed; we can analyze relevant information on a project, such as the contributors' activities, financial information, and development status. We adopted market capitalization as the substitution index of future prospects and the number of contributors and analyzed the relationship using time series analysis techniques, such as the Granger causality test and regression. We found that the number of contributors increases two months after market capitalization increases. This quantifies the impact of the future prospects of the project, i.e., of the market capitalization of a cryptocurrency, on the participation of contributors.

Sufficient computation time to obtain stationary results for long wave oscillations in harbors by Boussinesq model was investigated. For different data lengths (computation times), wave spectra and significant wave heights of long waves were computed with a model harbor and several incident wave spectra. It was found that the length of the computation time to obtain stationary values are significantly influenced by frequency characteristic of amplification factor of water surface oscillations and the periods of the beats consisting of adjacent components of the incident random waves, and that the time length is generally much longer than that which is expected from random wave statistics.