1. Simulation Research on the Course of Urbanization ------Method to build the relations between sub-systems, a case in Chengdu, China Yang Chenggang Population Research Institute, Southwestern University of Finance and Economics, China

2. Dynamic mechanism of urbanization in the system of feedback loop 1 almost every major factors in human society like population, resource, environment, economic growth and social development will be affected by the process of urbanization; 1 almost every major factors in human society like population, resource, environment, economic growth and social development will be affected by the process of urbanization; 2 the process of urbanization will be limited by almost every major factors like population, resource, environment, economic growth and social development. 2 the process of urbanization will be limited by almost every major factors like population, resource, environment, economic growth and social development.

3. urbanization has influence on PREGS Population: decrease fertility Population: decrease fertility Resource: cost more resource Resource: cost more resource Environment: lower quality of environment Environment: lower quality of environment Growth : accelerate economic growth Growth : accelerate economic growth Society: promote social development Society: promote social development

4. The process of urbanization will be limited by PREGS Judgement on moderation of urbanization scale should be never only based on economic goal; Judgement on moderation of urbanization scale should be never only based on economic goal; the model of moderation of urbanization scale should be a multiple objective model which is included population, resource, environment, economic growth and social development. It should be Pareto Optimum based on multiple goal. the model of moderation of urbanization scale should be a multiple objective model which is included population, resource, environment, economic growth and social development. It should be Pareto Optimum based on multiple goal. In reality, the model of moderation of urbanization scale is a short slab pattern of multiple goal, i.e. pattern of weakness overspill. In reality, the model of moderation of urbanization scale is a short slab pattern of multiple goal, i.e. pattern of weakness overspill.

5. Simulation of feedback loop of the process of urbanization Diagram 1 Diagram 1 population environment urbanization resource Growth (economy) Society

6. Methods First, build up the relationship of sub-systems and forecast the change of their feedback loop. First, build up the relationship of sub-systems and forecast the change of their feedback loop. Second, cointegration analysis of relations between urbanization and sub-systems, forecast the process of urbanization and the change of sub-systems. Second, cointegration analysis of relations between urbanization and sub-systems, forecast the process of urbanization and the change of sub-systems. Third, find out weakness sub-system, rebuild its cointegration relations to urbanization, amend predicted value. Third, find out weakness sub-system, rebuild its cointegration relations to urbanization, amend predicted value. Forth, evaluation on result of prediction. Forth, evaluation on result of prediction.

7. Example :a case of city, chengdu, China it can be found that total domestic electricity consumption and the logarithm of k have nearly the same linear growth trends, which indicates there may be the co-integration relationship between them. Base on e=z+591.593-196.147lnk, substitute the actual value of z and lnk, obtain e sequence and test its co-integration, and then we could find e is a stable sequence as well as a 0-order integration. So obviously variables z and lnk is (2, 2) Co-integration, which have a long-term stability. That is to say, there is a long-term stable relationship of growth in the same direction between Residents electricity consumption and the economic level of urbanization, and their dynamic changes are determined by the common random.

8. .Setting an Economic Parameter for Urbanization Table 1 Indicators of Chengdu Urbanization year Non- agricultur al populat io n ratio % y1 Total output of the tertiary industry ten million RMB y2 proportion of the tertiary industry in GDP % y3 urban actual disposable income per capita RMB y4 Economic Parameter for Urbanization (EPU) lny 199430.3231.141.29394120.8538 199530.97300.0242.04411321.1973 199631.62366.7442.15432721.4723 199732.2430.0542.7479721.7658 199832.83481.8243.7522122.0066 199933.5533.944.86592022.2813 200034.13597.5145.51649722.52 200134.79684.1545.85685622.7358 200235.56764.8245.88766022.9806 200336.98862.2746.09821423.2142 200442.821057.2352.05873423.7476 200550.271182.2149.87956424.0677 Note: Data is from Chengdu Statistical Yearbook 1995 to 2006

9. k grows linearly with time, which indicates steady economic growth of Chengdu city. Graph 1 K Curve With Time

10. the domestic electricity consumption of Chengdu residents is growing over time. Graph 2 Domestic Electricity Consumption of Chengdu Residents Unit: 10 million kwh Note: Data is from Chengdu Statistical Yearbook 1995 to 2006

11. Unit Root Test Unit Root Test Table 2 ADF Test Results of z and lnk original sequ ence ADFfirst difference sequenceADF second difference sequence ADF critical valu e z2.4739D z-1.9956 D Z,2 -4.65111%-4.4613 5%-3.2695 lnk0.1371D lnk-2.7800D(lnk,2)-4.963210%-2.7822 Table 2 shows that they meet the necessary conditions on structuring the co-integration equation.

12. Co-integration Test Co-integration Test Graph 4 Residuals and Fit Graph of Co-integration Model

13. Table 4 Forecast on EPU of Chengdu one-dimensional linear regression AR (1) modelautoregressive model with the time variable model Model test lnk t =-21.545+0.0123t R²=0.9938 F=1616.98 S.E=0.0037 lnk t =1.0042lnk t-1 R²=0.9914 F=2752.195 S.E=0.0004 lnk t =-12.6+0.0072t+0.4097lnk t-1 R²=0.9936 F=623.3347 S.E=0.0036 2006 3.18853.19433.1887 2007 3.20083.20773.2009 2008 3.21313.22123.2132 2009 3.22543.23473.2254 2010 3.23783.24833.2376 2011 3.25013.26203.2499 2012 3.26243.27573.2621 2013 3.27483.28953.2743 2014 3.28713.30333.2866 2015 3.29943.31723.2988 2016 3.31173.33113.3110 2017 3.32413.34513.3233 2018 3.33643.35923.3355 2019 3.34873.37333.3477 2020 3.36113.38753.3600 Note: in this table, lnkt figures the logarithmic predictive value of EPU, in accordance with the above test results, the test results of the three models are satisfactory, all the standards have been met basically.

14. Forecast on Total Quantity for Chengdu Domestic Electricity According to the above established mathematical model and forecast economic parameters of the urbanization, it can be predicted in 2010, 2015 and 2020 the total quantity for Chengdu domestic electricity amounts to 4.416 billion kWh, 5.669 billion kWh and 6.932 billion kWh respectively, which are 1.3 times, 1.7 times and 2.1 times of that of 2005 in Chengdu. According to the above established mathematical model and forecast economic parameters of the urbanization, it can be predicted in 2010, 2015 and 2020 the total quantity for Chengdu domestic electricity amounts to 4.416 billion kWh, 5.669 billion kWh and 6.932 billion kWh respectively, which are 1.3 times, 1.7 times and 2.1 times of that of 2005 in Chengdu.

15. Thanks! Contact: Yang Chenggang, Population Research Institute, Southwestern University of Finance & Economics, Chengdu, China 610074 Email: cd6369@163.com