Research groups at Hokkaido University, Nara Institute of Science and Technology, and Okayama University calculated patterns for combining prefectures nationwide for each adjacent region, and found that there were approximately 1,098 million.This is the first time that all combinations have been derived, and it is expected that it can be used for geographical analysis of disease distribution.Joint research by Professor Shinichi Minato and Professor Masahiro Mizuta of Hokkaido University, Assistant Professor Jun Kawahara of Nara Institute of Science and Technology, Professor Koji Kurihara of Okayama University, and Associate Professor Fumio Ishioka.
When analyzing geographical features in statistical surveys, etc., it is possible to consider regional features over a wider area than by prefecture by using adjacent information such as "Kansai 2 prefectures and 4 prefectures".Therefore, the number of combinations of adjacent blocks consisting of multiple prefectures can be basic data in the field of statistics, but the result of comprehensively counting all of these has not been known in the past.
The research group uses a special mathematical technique that can efficiently and quickly process a huge number of combinations to calculate adjacent patterns.In addition to neighboring prefectures that are connected to each other, cases connected by bridges or tunnels, such as Hokkaido and Aomori prefectures, and Okayama and Kagawa prefectures, were also classified as adjacent blocks.
This technique can be applied to combinations of cities, wards, towns and villages in each prefecture, and combinations of 50 states in the United States.It is expected to be used for detection of areas at risk of infectious diseases and pollution, analysis of basic data for measures against declining birthrate and aging population such as birth rate and mortality rate, and geographical analysis of economic activities.
In addition, you can accurately determine whether the geographic bias seen in the actual data is just a coincidence or an unknown cause, and quickly identify adjacent blocks that meet various constraints, including or not including specific prefectures. It is said that detection is effective in speeding up statistical processing.
All of these results are indexed and published by the National Statistics Center as important basic data for statistical analysis of geographical distribution in official statistics and epidemiological surveys.
