The Nonlinear Two-sex Population Model Of Innovation: Sex Ratio At Birth In China Parameter Identification And Assessment (2000-2006)

The 16th National Party Congress proposes that the first 20 years of 21st century is an important period of strategic opportunities we must seize all opportunities to accelerate our development. We must concentrate our efforts on building a moderately prosperous society in all aspects. The Fourth Plenum of the 16th Communist Plenary Congress proposes the further goal of building a harmonious Socialism society, which requires that population growth should be compatible with socio-economic development and be concerted with resource utilization and environmental protection. The number of Chinese population is the biggest in the world, if we want to promote the economic development and achieve sustainable development of society and economy, we must pay attention to the existing population problems. The security problem of population is one of the most basic and important security problems for a county.From the point of developing social economy, we also find that there are many disadvantages having a great influence on the population security of our country. The imbalance of population sex structure is becoming more and more serious. According to the 2000 census data of China, the SRBs(Sex Ratio at Birth) is 116.9. According to People's Daily in 6 of July of 2007, the number of males is 37 million more than females. It will cause a lot of social issues, such as Marriage Squeeze, social and economic development, social stability, the quality of living a relatively comfortable life. It will affect coordinated and sustainable development of economy, resources and environment.Until now, the research about China Sex Ratio at Birth all based on One-sex Population Model. Researchers who carry on their research based on Two-sex Population Model still have not analysis China Sex Ratio at Birth problem with Two-sex Population Model.A China Sex Structure at Birth Simulation model will be proposed in this paper. This model based on the Nonlinear Two-sex Population Model, which was proposed in 1992 by professor Mi-Hong.. In addition, this model integrated the theory of system identification, transformed some problems into system identification problems, and estimated parameter with the Least Square Method. At the same time, a method which integrated the theory of Optimization, transformed some problems into Unconstraint Optimization Problems and estimated parameter with Newton Method is also proposed in this paper.In this foundation, based on the population data which was published by the State Statistics Bureau and part data of the 2000 census of China, this paper applied this Simulation model to estimate the Sex Structure at Birth during 2000 to 2005 and 2000 to 2006 and come to the conclusion as following:(1) The Sex Structure at Birth during this period is between 113.4 and 114.9.(2) In comparison with the Sex Structure at Birth in 2000, it was cut by 2 to 3.5 percentage point.At last, this China Sex Structure at Birth Simulation model was realized by programming language C#.