Hidefumi Ogata

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Scalable analysis of massive graphs has become a challenging issue in high performance computing environments. ScaleGraph is an X10 library aimed for large scale graph analysis scenarios. This paper evaluates scalability of ScaleGraph library for degree distribution calculation, betweeness centrality, and spectral clustering algorithms. We make scalability(More)
This paper describes in a formal way a data schema model which introduces temporal and versioning schema features in an object-oriented environment. In our model, the schema is time dependent and the history of the changes which occur on its elements are kept into version hierarchies. A fundamental assumption behind our approach is that a new schema(More)
Periodic elasticity problem is attractive subject and important from the theoretical and practical viewpoints. In this paper, we propose a fundamental solution method for elasticity problems of planes with one-dimensional periodic structure. The fundamental solution method [4, 15] is a numerical solver for partial differential equation problems and is(More)
Wheelchair sports were developed for people with spinal cord injuries, and have contributed greatly to the improvement of physical fitness and social interaction of handicapped people. Previously, wheelchair sports were used as a method of rehabilitation to increase the recreational activity of wheelchair-bound persons. Recently, however wheelchair sports(More)
This paper describes in a formal way a data schema model which introduces temporal and versioning schema features in an objectoriented environment. In our model, the schema is time dependent and the history of the changes which occur on its elements are kept into version hierarchies. A fundamental assumption behind our approach is that a new schema speci(More)
Large graph analysis has become a widely studied area in recent years. Clustering is one of the most important types of analysis that has versatile applications such as community detection in social networks, image segmentation, graph partitioning, etc. However, existing clustering algorithms do not intend for large scale graphs. To solve this problem, we(More)