Akinori Okada is a Professor Emeritus of Rikkyo University, and holds a Ph.D. in Engineering from Keio University. Okada obtained his undergraduate degree of engineering from Keio Universality in 1966. After studied at the graduate school of Keio Universality, he became a research assistant at Chiba University in 1971. He moved to the School of Social Relations of Rikkyo University in 1972, and was appointed a Professor in 1981. From 2007 to 2014, he was a Professor of Tama University. His research interests are the areas in dealing with asymmetric relationships by multidimensional scaling and cluster analysis. He published a book titled ‘Methods for the Analysis of Asymmetric Proximity Data’ with Giuseppe Bove and Donatella Vicari in 2021. He is a series editor of the book series ‘Behaviormetrics: Quantitative Approaches to Human Behavior’, a founding editor of the journal ‘Advance in Data Analysis and Classification’, and a coordinating editor of the journal ‘Behaviormetrika’. Okada assumed the position of the president of the International Federation of Classification Societies: IFCS (2016-2017), the president of the Behaviormetric Society (2012-2015), and the president of the Japanese Classification Society: JCS (2005-2009). He is a Fellow Member of the Operations Research Society of Japan and the JCS. He launched the first International Meeting of Psychometric Society (IMPS) with Yutaka Kano, Jacqueline Meulman, Kazuo Shigemasu, and Haruo Yanai in 2000, and started the Japanese-German (German-Japanese) Symposium on Classification with Wolfgung Gaul, Hans Hermann Bock, and Keiji Yajima in 2005.Kazuo Shigemasu is Professor Emeritus of the University of Tokyo and currently the visiting professor at Keio University. He earned his B.A. in Educational Psychology in 1968 from Tokyo University and his Ph.D. in 1974 in Psychometrics from University of Iowa. His specialization is psychometrics and data analysis in psychology. He hastaught Bayesian Statistics for many years to social scientists at Tohoku University, Tokyo Institute of Technology, The University of Tokyo, Teikyo University etc. He served as the President of the Behaviormetric Society, Japanese Psychological Association, Japan Association for Practice on Testing and the Japanese Society of Theoretical Psychology. He also served as the chairman of the organizing committee of International Congress of Psychology (ICP) held in Yokohama in 2016.Ryozo Yoshino is Professor Emeritus, The Institute of Statistical Mathematics and The Graduate University for Advanced Studies. He received his B.A. in Psychology from Tokyo University in 1980 and his Ph. D. in 1988 from the Cognitive Science Group at the University of California, Irvine. In 1989, he joined the Social Survey Group of the Institute of Statistical Mathematics in Tokyo. Since then, he has been engaged in empirical research on public opinion surveys, cross-national comparative socialsurveys on national character, and mathematical modeling of the dynamism of social consciousness for over 30 years. Since 2022, he has served as President of the Japan Association for Public Opinion Research (JAPOR), which was founded in 1948 as a voluntary organization under the guidance of the U.S. government to promote postwar democracy and became an incorporated foundation in 1950. He has published many papers in national and international journals, including Behaviormetrika and the Japanese Journal of Behaviormetrika. Two recent books are published by Springer: Cultural Manifold Analysis -Methodology on Cross-National and Longitudinal Survey of National Character (Yoshino, 2021) ; “People and Trust”, a chapter of the book, Advanced Studies in Behaviormetrics and Data Science (Imaizumi, Nakayama & Yokoyama [eds.], 2019, pp.409-472). Satoru Yokoyama is an Associate Professor at Department of Marketing, School of Business, Aoyama Gakuin University. Hegraduated from the Department of Administration Engineering, Faculty of Science and Technology, Keio University in 2003, and received his Ph.D in Engineering in 2009 from Keio University. He became an assistant professor at the Department of Business Administration Faculty of Economics Teikyo University in 2010, a deputy associate professor in 2013, and has been in his current position since 2017. His research focuses on methods for proximity data analysis, especially on proposing and improving models for multidimensional scaling and overlapping cluster analysis. Recently, he has also been interested in the application of multivariate analysis methods, including proximity data analysis methods, to the field of marketing. He had published several papers in academic journals, including the Japanese Journal of Behaviormetrika, Computational Statistics and the Springer's book series of "Studies in Classification, Data Analysis, and Knowledge Organization". He contributed to the publication of "Advanced Studies in Behaviormetrics and Data Science: Essays in Honor of Akinori Okada" as one of the editors.
