# Faculty

## Hiroyoshi Miwa

### Major research activity

The research field of our laboratory is Applied Mathematics and Physics. We face numerous problems that need to be solved in practical applications from many areas such as operations research, communication networks, bioinformatics, management, economics, social science. To overcome these problems, applied mathematics and physics including mathematical modeling, analysis, optimization and algorithm, and control of complicated large-scale systems are very useful. Mathematical modeling and analysis are used to formulate various problems and to analyze their mathematical properties. Also, efficient algorithms and data structures utilizing the properties are designed to solve the problems or to optimize the performance. We contribute not only to solving practical problems but also to developing the theoretical foundation on optimization theory, algorithm theory, computational complexity theory, graph theory, and discrete mathematics. While complicated large-scale systems in the real world such as human mobility and social networks have many interesting properties, they have not been sufficiently investigated so far, because we had to deal with big data. We theoretically and numerically analyze such systems by developing efficient algorithms, and we attempt to find new properties and to design algorithms to control large-scale systems.

### Major relevant publications

- A. Fujihara, H. Miwa, Homesick Levy Walk: A Mobility Model having Ichi-go Ichi-e and Scale-Free Properties of Human Encounters, Proc. IEEE COMPSAC2014, Västerås, Sweden 21–25 July, 2014.
- Y. Takayama, H. Miwa, Delay Tolerant Navigation Method for Fast Evacuation in Poor Communication Environment at the Time of Disaster. International Journal of Distributed Systems and Technologies, Vol. 6, No. 3, pp.29-50, 2015.
- A. Fujihara, M. Uchida, and H. Miwa, Universal Power Laws in the Threshold Network Model: A Theoretical Analysis Based on Extreme Value Theory, Physica A, Vol. 389, Issue 5, pp. 1124-1130, Mar., 2010.
- K. Matsumoto, H. Miwa, and T. Ibaraki, Scheduling of corrugated paper production, European Journal of Operational Research, Vol.192, No.3, pp.782-792, 2009.
- N. Masuda, H. Miwa, and N. Konno, Geographical threshold graphs with small-world and scale-free properties, Physical Review E, Vol. 71, 036108, 2005.