Abstract
Scientific prediction and accurate grasp of the future trend of population change are conducive to the formulation of different population policies at different stages, so as to alleviate the adverse effects of the aging population on society and provide scientific theoretical reference for controlling the population size and making policy. Considering that the population system is affected by many complex factors and the structural relationship among these factors is complex, it can be regarded as a typical dynamic grey system. In this paper, the fractional-order GM (1, 1) model and the fractional-order Verhulst model are established, respectively, based on the statistical data of China's population indices from 2015 to 2019 to forecast the population size and the change trend of population structure of China from 2015 to 2050 in the short-term and medium- to long-term. The forecast results show that China’s population will grow in an inverse S shape from 2015 to 2050, when the total population will reach 1.43 billion. Moreover, during this period, the birth rate and natural growth rate of population will decrease year by year, and the proportion of aging population and the dependency ratio of population will increase year by year. Besides, the problem of aging population is going to become increasingly serious. The application of grey system method to population prediction can mine the complex information contained in the population number series. Meanwhile, the fractional-order accumulation can weaken the randomness of the original data series and reduce the influence of external disturbance factors, so it is a simple and effective population prediction method.
Highlights
China is the country with the largest population in the world
By 2018, the natural growth rate of China’s population has been below 4‰, achieving the target of low population growth, and the population growth is in an important period of transition to a low rate of birth, death, and growth. e number and structure of the population can reflect the level of economic development of a region, and it is the indicator to measure social progress. e change of population will affect the formulation of basic state policies, the arrangement of employment, the development of social welfare, and even the standardization of national economic and social development strategies
According to the grey system theory, when the development coefficient is a ∈ (−2, 2) and a ≥ − 0.3, the grey fractional-order model can be used for medium- to long-term prediction
Summary
China is the country with the largest population in the world. From the perspective of the process of population development, China’s population grew at a relatively high speed from the early years after the founding of the People’s Republic of China to the end of the 1970s. Grey system theory is a borderline subject with large cross-section, strong permeability, and wide application It takes the uncertain system with small samples and poor information with “partial information known and partial information unknown” as the research object, mainly through the generation and development of some known information to extract valuable information, achieving the effective control on the system operation law [8, 9]. Wu proposed a novel nonlinear grey Bernoulli model with fractional-order accumulation (FANGBM (1, 1)) to forecast short-term renewable energy consumption of China during the 13th Five-Year Plan [20].
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