2026-03-15T17:06:48Z https://jcga.repo.nii.ac.jp/oai

oai:jcga.repo.nii.ac.jp:00000227 2023-10-06T05:17:30Z 1:9:53

微分方程式による日本の人口変動モデル On a Model of Population Growth in Japan with Differential Equations 河本, 直紀 449 カワモト, ナオキ KAWAMOTO, Naoki 450 population Malthusian model differential equation linear approximation Abstract In Japan, the population has been recorded from 1872. It is well known that the Malthusian model can be applied until around 1970, but afterward the growth rate is declining and the result of the model is different from the real population. We consider the time dependent growth rate and construct a more realistic model. The growth rate is approximated by linear functions of time, determined from the data. The whole period from 1872 till 2009 is divided into two parts by the year 1973. For each period we the linear approximation of the growth rate. Our model can reproduce the population in Japan fairly well, and we can estimate the future population. departmental bulletin paper 海上保安大学校 2012-03-30 VoR application/pdf 海上保安大学校研究報告, 理工学系 1-2 55 45 48 Report of Japan Coast Guard Academy Part 2 (The Science and Engineering Section) AN10088865 0287-2951 https://jcga.repo.nii.ac.jp/record/227/files/2_55-1-77-06_Kawamoto.pdf https://doi.org/10.15053/0000000227 https://jcga.repo.nii.ac.jp/records/227 jpn 10.15053/2011.21.06