1. Biostatistics Group, Data Science Department, Development Division, Mitsubishi Tanabe Pharma Corporation, 2-2-6 Nihonbashi-Honcho, Chuo-ku, Tokyo 103-8405, Japan.
2. Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
3. Department of Math, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.