And the review Since the second half of the 20th century, the remuneration of unskilled labor has declined in comparison to skilled labor in many countries, especially in the past 30 years, especially in the Anglo-American and other industrialized countries. Take the income distribution data of the US labor market as an example. In 1990, the proportion of unskilled labor relative to skilled labor was about one-twentieth of that in 1940. 1 If the salary ratio of college graduates and high school graduates is used to characterize the wage gap between skilled and unskilled labor, the wage ratio of both 1965 and 1995 climbed from 1.45 to 1.70, reaching the highest point since 1915 in 2005. In 2008, the salary of college graduates was 97% higher than that of high school graduates. This article is the New Century Excellent Talents Project of the Ministry of Education (NCET-12-0818), the National Social Science Fund General Project (14BL031), and the National Social Science Fund Youth. Phased results of the project (12CY007), the Jilin Provincial Social Science Fund Project (2013B44), and the Jilin University Youth Academic Leadership Development Program (2012FRLX16).
And this is happening in an environment where the number of college graduates has tripled. 1 According to the supply and demand theorem, when the supply of skilled labor increases in a large scale, the compensation for skilled labor should decrease, but this phenomenon does not appear in the United States.
On the contrary, the reward for skilled labor is obviously increasing. Of course, such phenomena have also appeared in developing countries. 2 It shows that economic development does not benefit all workers equally. Instead, there is a phenomenon of non-equalization of labor compensation and skill premium, that is, higher wages of highly skilled workers. 3 Why is the supply of higher-quality skilled labor increased, and the wage gap between skilled and unskilled labor will continue to widen, and a large number of studies attribute it to the result of the bias of technological progress skills. Daron Acemoglu and David Autor assume that the skills and non-skilled labor input by the enterprise cannot be completely replaced. If the technological improvement is biased by the rate of change of relative factor-promoting technological progress, the biased technology is found. Progress can explain the problem of skill premium, that is, the advancement of technology towards the development of skills, and ultimately the unequal wages of labor, which has been continuously verified in empirical research. Often, the development of technology is not necessarily unbiased or neutral, and often exhibits biased characteristics. In order to further explain the phenomenon of wage decline in the manufacturing industry in the United States from 1959 to 1996, the construction of a generalized index, the impact of technological progress on labor supply and demand, and the discovery of changes in skills and unskilled labor demand can be attributed to The result of the role of non-neutral technology advancement. 1 Such non-neutral technological advances can often be embodied in the computer field, especially the technology embodied in the materialized form of information, communication and software capital goods. It is this kind of non-neutral technological advancement that makes the production of new products more technically intensive, and because of the adaptability of skilled labor, enterprises are more willing to hire skilled labor. 2 If the company assumes that only the three elements of capital, skilled labor and unskilled labor are invested, the production of products meets the fixed substitution elasticity (CES) production technology, and the relationship between the marginal output of skilled labor and unskilled labor and the input of factors indicates that The increase in the size of equipment capital investment, the demand for skills also increased, and the skill premium is expanding. 3 That is, with the increase of equipment investment, the technology combined with equipment investment requires that the use of machines and the production of products are mainly completed by skilled labor, which induces the combination of new technology application and skill labor to be more closely combined. Onathan E. Haskel and Matthew. Slaughter used empirical data from 10 OECD countries from 1970 to 1980, and found that increased skill labor compensation also induced technological innovation toward technology-intensive factors. The direction of development indicates that there is a positive effect on the bias of technical labor skills.
Some scholars in China also pay attention to the influence of technological progress skill bias on factor income inequality, divide labor into skill and non-skills, and introduce regression analysis of skill-biased technological progress. The results show that China's technological progress performance from 1978 to 2007 The skill bias, and the non-neutral technology and skill labor contained in the machine and equipment show a stronger complementary relationship, indicating that the technological progress in China is biased and triggers a skill premium. 1 Of course, this may be the introduction of more complementary technology from skilled labor in developed countries in the process of reform and opening up, thereby increasing the demand for skilled labor in the country and expanding the wage gap. 2 In addition, some scholars use the regression analysis method to explain the reasons for the inequality of skills and unskilled labor compensation from the perspective of complementary skills and labor. 3 The development of modern technology and skill labor are more complementary, not substitute, which makes people believe that technological progress and skilled labor have complementary relationships. In fact, the history of modern economic and technological development shows that whether the two manifest themselves as substitution or complementarity often depends on the nature of technological progress itself. If technological advancement or technological innovation merely simplifies existing production technology processes, such as breaking down complex labor into simple labor on the assembly line, technological progress and skilled labor may exhibit an alternative relationship. For example, in the early days of the British industrial revolution, the great development of the machine industry replaced the simple operation of workers with skilled craftsmen in the original craft workshops or workshops, and replaced a lot of handicraft technicians with a series of specialized assembly line technologies. 4 For example, the new generation of computer software is easier and easier to operate than its predecessor, and it is easier to improve the labor efficiency and labor demand of ordinary users, thereby reducing the demand for computer professionals. 5 Conversely, if technological advancement increases the complexity of product production and technical environment, it is more likely to show a complementary relationship with skilled labor. After the 1990s, technological development has increasingly demonstrated the characteristics of investment specificity. The technical environment and the complexity of new product production have higher requirements on the skill level of workers, and skilled labor can reduce the efficiency loss caused by the incompatibility of technological innovation. Being able to learn new technologies in a shorter period of time, so in the period of technological innovation, the advantages of skilled labor are greater, and it is easier to complement technological progress. In the modern and ever-changing technological environment, workers have higher skill levels, and technology development naturally tends to skill labor. 6 Technological advancement bias is important to improve the demand and reward of skilled labor, but it does not mean that the skill premium is only the result of the biased technological progress, and the change of supply and demand of skilled labor itself plays an important role. If the supply of skilled labor increases in a short period of time, it will inevitably have an impact on skilled labor compensation. Suppression skills Zou Wei, Liu Yong: Dynamic research on skilled labor, economic transformation and income inequality, World Economy, 2010, No. 6.
Premium. However, if technological progress is directed towards the development of skilled labor, it will eventually lead to higher demand for skilled labor, and the short-term supply of skilled labor cannot be adjusted accordingly. As a result, the compensation for skilled labor will be increased, and the gap in labor income distribution will be widened. . 1 The closer the combination of skill labor and technological advancement skills bias, the greater the skill premium. Asimoglu introduced the RD expenditure of the R&D department, analyzed the formation process of technological progress bias in production, and found that the proportion of high-skilled workers is increasing, and the technology complementary to skilled labor will have a larger market, and the market scale will expand. It also guided the R&D department to improve the research and development of this complementary technology. The mutual strengthening of the two causes the wage gap between skilled labor and unskilled labor to widen. 2 In addition, if the adaptation time of the labor force to the new technology is introduced into the technical model, the skilled labor can adapt to the new technology with lower adjustment cost and shorter time, and start to work efficiently, while the non-skilled labor is still in the new technology. The adaptation phase. Thus, in the early days of the application of new technologies, the wage gap between skilled and unskilled labor will increase. 3 However, when unskilled workers also master new technologies, the wage gap will shrink. In other words, the technological advancement skill bias will generate a skill premium, but this effect may be short-term. As the skill level of unskilled workers increases, the increase in the supply of skilled labor tends to narrow the wage gap between the two.
Of course, workers can also change their skill level through individual education investment and improve the supply of skilled labor in society. Between 1991 and 2006, the wage inequality of Chinese workers increased significantly, and the positive effect of education return on education premium was obvious. However, the average degree of education of workers increased, and the income level of the overall laborers was reduced. Income inequality. 5 Steven G. Allen uses data from the US industrial sector to examine the impact of education on wages and technological advances on education returns, and finds that high-tech industry education returns are high, with 30% of skill premiums attributed to investment in education. the result of. 6 It is also the reason that the development of education and the change of investment income of education affect the supply of skilled labor. From 1940 to 1998, the relative wages of American college students and high school graduates showed a “W-shaped trend†of first drop, then rise, fall again, and then rise again. After China's reform and opening up, the wage ratio of skilled and unskilled labor also showed a similar "W-type trend." Because different Dong Zhiqing and Wang Linhui: labor market demand differentiation and skill premium stem from technological progress, economists have different birth rates and growth rates in different periods, university enrollment, human capital stocks, and cyclical changes in technological progress and skill premiums. Levels will also show different trends. 1 For example, when the US labor supply increased from 1971 to 1979 (baby boom in the 1960s) and most of the labor force was well educated, the US skill premium continued to decrease during this period. In 1979-1987, due to insufficient supply of skilled labor, the skill premium returned to the upward trend. These phenomena suggest that the investment mode of education can effectively improve the skill level of ordinary workers and increase the supply of skilled labor, thus effectively suppressing or even eliminating wage inequality.
The above research shows that biased technology advancement has a strong explanatory power for skill premium. However, empirical research pays more attention to the relationship between technological progress and labor compensation, and does not measure the difference in the effect of technological progress on labor compensation. This paper from the perspective of individual education choice, the supply of biochemical skills, through the mathematical model, deducting the coupling mechanism of technological progress and skill premium, quantitatively measuring the bias of China's technological progress skills, and the direction of different technological advances to labor supply and skill premium. influences. The difference between this article and others is manifested in two aspects. The first is to introduce the individual's educational choices, the supply process of endogenous skills and labor, and to interpret the mechanism of the direction of technological progress on the compensation of skilled labor. Second, traditional research focuses more on qualitative descriptions of technological advancement, or simply uses regression methods to test the relationship between biased technological advancement and skilled labor and skill premium. This paper not only constructs the technical progress bias index, estimates the strength of skill bias, quantitatively calculates the share of skill premium explained by skill-biased technological progress, and compares the different effects of technological progress on labor supply and skill premium through numerical simulation. . The remaining structure of this paper is arranged as follows: the second part is the theoretical model; the third part is the indicator design and data source description; the fourth part is the numerical simulation result and evaluation; the fifth part is the basic conclusion.
Second, the theoretical model hypothesis 1: Assume that the laborer only survives the second period and the ability is q, q is a random variable subject to a fixed distribution. At the initial moment of each period, the laborer decides the behavior of the current period, including the labor time and the level of consumption. The total number of laborers in each period is unitized to 1, assuming that the laborer's time can be divided into labor time and leisure time predictions, assuming that the laborer's prediction of future wages satisfies "rational expectations" 2 ie wt+1=wtl. Hypothesis 2 : Assume that an individual can become skilled labor through educational choices. At the beginning of each new labor force, in the duration of the payment, the higher education cost Cedu(q) is used for learning and there is no labor income. In the second duration, it becomes the skill labor to obtain the skill compensation. If you do not accept higher education, you will become unskilled workers directly, and you will receive unskilled labor as unskilled workers throughout the life.
The total utility of the individuals entering the t-term is: the total utility U; the expected utility of the laborer becoming non-skilled and skilled labor. Uu and Uth represent the utility of becoming unskilled labor and skilled labor, respectively, which are the sum of the two phases of utility of the worker. Cf,t is the first class 3 (S=u is unskilled labor, S=h is skill labor) labor consumption, and i represents the laborer's duration. Ltt indicates labor time. u(C,1) is the instantaneous utility function, and the instantaneous utility is determined by the current consumption and labor time, specifically 1). Among them, Mary is the parameter, v=1, 2 represents the duration of the laborer, timev is the total time of the laborer, timei= 1, time2=n, which is the discount rate of future utility.
Whether the workforce is accepted for higher education depends on its future utility: for skilled workers.
Suppose that the manufacturer uses skill and non-skilled labor to organize production, and the production technology satisfies the form of CES function of constant substitution elasticity: Am and Aht are the technical efficiency parameters of unskilled and skilled labor, respectively, and the substitution elasticity of skill and unskilled labor is 1/ (1 - P) > 0, A is a neutral technological advancement.
In order to distinguish the difference in labor supply between different types of labor in unit time, define Lht as total effective skill labor, Lm as total effective unskilled labor, and effective labor as the product of labor time and labor ability, which is expressed by formula: For the condition, the partial bias is: in which the efficiency wage ws is the labor remuneration obtained by the unit time and unit capacity of the s-type labor, and the wage obtained from the labor unit time is wageS=å·§Sq, s=u, h. The relative technical efficiency of characterizing two types of labor is the advancement of skill-biased technology and affects the relative wages of labor. 1 Conclusion 1: If the supply of skilled and unskilled labor is constant, Neutral technological progress At will increase the wages of skilled and unskilled labor in the same proportion, but has no effect on the wage ratio of the two, that is, unbiased neutral characteristics. The skill-biased technological advancement has a direct impact on the labor-wife ratio, that is, the skill premium is triggered by the relative wages that are more conducive to improving the skilled labor, and its intensity depends on its own level and labor substitution elasticity.
Because of the type of labor that workers initially want to become, there is a need to make choices about whether to accept higher education. In its initial period, estimates of future labor income are based entirely on observations and experiences of past data. Assume that the laborer estimates his future labor income and consumption ratio based on the information of the previous period, according to rational expectations: and labor time. Cedu(q) is the cost of higher education. The stronger the ability of the worker, the lower the cost of education (high-capacity students have significant advantages such as scholarships, free time, work-study and entrepreneurship, and their hidden costs are lower, such as easier learning and higher interest). The education cost is set as a linear function of the laborer's ability: 2 where P. and the parameter called the education cost function, the above related function is substituted into the formula (2), and the conditions for the choice of laborers are selected: It shows that for individuals to receive higher education, it depends on the comparison of q and qt=P./+. When 9>9丨, the individual will choose to accept higher education and become skilled labor; for q The following is a review of the optimal behavior of the two types of labor. First of all, for skilled workers, the utility of the two phases is maximized as: the value. The above-mentioned maximizing utility problem is a two-stage dynamic optimization, and the reverse recursive method can be used to obtain the optimal labor time equation: the consumption level Cl. Combining the budget constraints of Ch, +i and ht+i, and transforming Kh into a function of Cl, the optimal derivation for Cl, where oh(oh/oh-1) is the next in t The rational expectation of the salary h+i. For the skilled workers who entered the t-term, the optimal labor time selected in the t+i period is: as can be seen from the above formula, as the labor that chooses to receive education during the t-term and becomes the skilled labor in the t+l period. The labor time supply is a function of wage t+i and ability q. L2, t+i is the subtraction function of (1)t+i, which is also the decreasing function of q. In particular, qXl2, t+i is a linear function of q, then the total expected labor supply of the t-skilled laborer can be transformed into the following form: if the variable before the t-term is regarded as known, then the above formula represents Ut only dependent In oh, and labor time is a decreasing function of oh. Secondly, for non-skilled workers, the two-stage utility maximization problem is: deriving cu, t+i and lut+i respectively, and sorting out: for expressing Q, +i and l, +i and Ku Substituting into the above formula, and then seeking partial guidance for Q1, and l, after finishing: Ku can be obtained at this time, and substituted into lU, t+1 formula can be obtained: observe the labor time of the two individuals, we can know The labor time of unskilled laborers has nothing to do with their ability, the first (n+BU-f+BO. considers a simple case, 1+BU=n(1+B1), S=n. At this time we can The labor time is not related to q, then the total expected labor supply of unskilled labor in t period is: we still regard the variable before t period as known, then the above formula shows that Lut can be expressed as a function of å¿’ and qU From the previous analysis, qU is also determined by å¿’ and 。. Therefore, if we substitute the expressions of (7) and qt into the above formula, Lut is also a function of å¿’ and å¿’. Direction, so the direction of action of Lt is also difficult to determine. However, since å¿’ only affects qU, it can be determined that the increase will reduce Lm.å¿’(8) Equation (9) shows the supply equation of t-skills and unskilled labor. Combining (4) and (5), you can get balanced wages and earning, and further derive the influence of skill-biased technological progress on relative wages. Order: Obviously, the sign of TCt depends on the symbols of the items in the braces. As can be seen from the above, the first item and the second item are both positive, the third item is negative, and the symbol of the fourth item cannot be determined. The direction of influence can not be directly determined. For this reason, in the next section we will use numerical methods to simulate the direction of influence and the intensity of impact on relative wages. Third, the indicator design and data source explanation rate, when 0, said that the technological progress is biased towards skilled labor; conversely, <0, said it is biased towards unskilled labor; equal to 0 is neutral technological progress. It can be seen that Hicks (ohnRichardfficks) and Asimoglu give a way to judge the direction of technological progress. 12 However, quantitative examination of technological advances tends to the level of a certain element, providing more informative information, based on a more powerful basis for the interpretation of skill premiums. To this end, this paper assumes that the two types of elements are skill labor U and non-skilled labor Lu, respectively, defining the technical progress skill bias, which means that when the skill labor and non-skill labor input ratio remain unchanged, the technological progress is to the skill and non-skilled labor. The impact of marginal productivity. If the total production function Y (AuU, AhU), wherein each Ah and Au and U, U represents enhance the efficiency of the production section of enhancing technical function of the type of neutral At corresponded to the classical definition of technical progress, the skill-biased type may be characterized skill improved. According to formulas (4) and (5), the skill-biased technological advancement at this time can be expressed as follows: According to the model, the technical progress of the skill-biased type in China is measured, mainly involving the following variables. (1) Labor supply time = (annual work months / 12) X (week labor days / 7) X (day labor hours / 24). Labor income = (monthly salary + monthly bonus) X working months. (3) According to the education level, the labor force with college degree or above is defined as skilled labor; the middle technical school, vocational school and duration are 23 to 58 years old, at this time n=9. There is no work corresponding to the education level of the labor force combined with the statistics of the Chinese Statistical Yearbook over the years. If there is an unknown item in the CHNS questionnaire answer (generally expressed as a negative number), choose to remove the sample directly. By processing the data for 2000, 2004, 2006, and 2009, we obtained the average annual income and average labor supply time for different types of labor for all ages in the four survey periods. As a measure of the ability of the workforce and the ability to learn, the q value should satisfy at least the following two conditions. First, the q value should be greater than 0, or q is less than 0 is a 4 small probability event, because q as entering the labor supply function should not have a negative value. Second, the q value should satisfy the two large and medium small probability distributions. Those with very high and very low abilities are a minority, and most people's abilities are at an average level. Based on this, combined with domestic and foreign research, 1 the q distribution is set to a normal distribution, the mean value is q=1, and the standard deviation is = 05. The national labor force for higher education is directly taken from the China Statistical Yearbook from 1952 to 2012. Number of college graduates. P values ​​for the parameters, according to research ideas elements of the elasticity of substitution, in contrast to domestic and foreign after taking into account the Dong Qing, et al 2013 straight through standardization system and method of nonlinear model seems irrelevant, it is estimated labor elasticity of substitution conclusion is robust, and The direct use of China's economic data estimation results may be more in line with the country's real labor substitution elasticity. This paper takes its parameter estimate of 0.947.2 according to the above indicators and related parameter values, and uses the labor relative wage formula to calculate the skill bias of each year. technical progress, the results in table 1. From table 1, characteristics of skill-biased biased technical progress protrude at five different values ​​of elastic parameters Alternatively, technological advances clearly show skill bias, and the bias intensity increasing. Table different alternative trends a skill-biased technical progress skill biased technical progress in elastic parameters, time four, numerical simulation and evaluation data availability constraints, the model parameters directly presence estimate certain degree of difficulty, so this section selection numerical simulation model was investigated. First set and calibrate the model parameters. According to the production function class, this paper sets the parameter 0.947 in the production function, the discount rate n 0.8853, and the education cost function parameter å©. The calibration of the å©, the distribution function of the ability q, so that it matches the ratio of the skill to the unskilled labor in 2006-2010 and the salary ratio, 1 calculated =2.004 and 1.12. Utility function parameter segment, B2U and rose calibration, Need the values ​​of At and ,. If At and, known, the relevant data (labor time and wages) are substituted into the expressions of 11, 1 and this, and B, B and B are inversely solved. Combining equations (4) and (5) and (8) and (9) can be obtained: the amount is two types of technological progress Ai and, as well as the labor time and wages in the lag period. When the exogenous variable is given and the initial value is given, the equations can solve the i-phase values ​​of the core, å¿’, Lui, Lhi and other variables. After several iterations, until the variables reach a steady state, the equilibrium of each variable can be obtained. value. We set different values ​​for Ai and , and solve the equilibrium values ​​of the two wages and labor supply. Initially set the iteration step size to 200. If the variable fluctuation (based on relative wages) is still large (based on the relative salary) after 200 times, the number of iterations can be extended appropriately, but we found that the variables after 200 iterations are Has been stable. We will first focus on the advancement of biased technology and the impact of change. According to the third part of the paper, the definition, combined with the domestic and foreign research on the skill-biased technological progress, the value of the parameter P in Table 1 is 0.947, the trend of the fitting. To better match the reality, it will be set to the value of 1.0474 in 2009, and the growth rate is set to an average growth rate of 0.018 in 2006-2009. The change is available in the following form: 1.4745. First, A is fixed to its initial value of 0.0463. In different, the following (11) type multiple iterations to obtain the equilibrium value of each variable, the results are shown in Table 2. Table 2 Neutral technology progress and biased technology progress! Variable, relative wages and labor The simulation results of the supply are not continued. Table 2 of Table 2 records the simulation results of the impact on the skill premium at different levels, relative wages, relative labor supply, and biased technological advances. The data shows that under the influence of technological progress skills bias The relative wages of the two types of labor continued to rise, the relative wage increased from 1.2521 to 1.6474, an increase of 32%, and the skill premium was obvious. At the same time, the relative supply of labor increased from 00329 to 0. 0837, an increase of 154%. Visible, technological progress Skill bias has significantly increased the relative wages of labor and the level of labor supply, but has a greater impact on labor supply. Moreover, as can be seen from the changes, the value continues to be positive, indicating Progress in technology is more conducive to improving the productivity of skilled labor. Modern technology and skilled labor show a trend of convergence. On average, skill-biased technological advancement, each 1% increase, will increase the skill premium by nearly 0.8%. Among them, biased The impact of technological progress on the relative changes in labor wages and labor supply can be described as: First, the impact of skill-biased technological advancement increases the labor productivity of skilled labor, thereby raising the wages of skilled labor to a higher position. Skills are higher than those of unskilled labor. Newly entered laborers will choose to become more skilled labor, and the number of skilled labor increases, and their relative labor supply and relative wages increase. The convergence trend of relative wages is relative to the process of convergence of labor supply, as shown in and. It can be seen that the relative wages and relative labor supply fluctuate around the equilibrium value of 1. 0.0546, and the fluctuation range is continuously narrowed. When the iteration period exceeds 200 times, the fluctuations are less than 0.001 regardless of relative wages or relative labor supply, and it can be determined that the model has reached a new equilibrium. Based on the above analysis and simulation results, it can be seen that when the technical progress skill bias is continuously strengthened, the relative wages of skilled labor will show an upward trend, and the relative labor supply of skilled labor will also show a steady increasing trend. In terms of intensity of action, the relative labor supply caused by the shock changes more than the relative wage. The reason for this phenomenon may be that the scale of China's skilled labor force is still at a relatively low level. At this stage, people's willingness to accept higher education is very strong. Under this circumstance, the relative wage increase brought about by the advancement of biased technology will be inhibited by the rapidly increasing supply of skilled labor, and finally the effect of biased technological advancement on labor supply will be greater. After examining the impact of changes on the model equilibrium, we again introduce the changes in the neutral technological progress At, and examine the impact of its changes on skilled labor and skill compensation. Among them, the neutral technological progress is set to increase from the initial value at a certain rate, and the growth rate is based on the average growth rate of China's total factor productivity (TFP). After calculation, it is found to be 0.035. Simulate the two cases with immutable conditions, and compare the effects of different technological advances on relative wages and relative labor supply. The results are shown in Table 3. Table 3 shows the simulation results of relative wages and relative labor supply when the neutral technological progress is variable. No change, change Continued Table 3 shows the trend of relative wages and relative labor supply under constant and variable conditions. First, we observe the left side of Table 3. When it is unchanged, the data shows that the advancement of neutral technology has lowered the level of skill premium. The relative wage of skilled labor has dropped from 1.2521 to 1.1471, a decrease of 8.4%. . On the contrary, the relative labor supply is on the rise, with an increase of 422%. It should be pointed out that neutral technological progress can affect the judgment of relative wages, and there is no contradiction with Conclusion 1. The knot is achieved in an environment where neutral technological advances do not have an impact on the supply of skilled labor. In the current model, the labor supply is determined by the economic system through the educational choice of the laborer and the maximum conditions for the final use. At this time, the neutral technological progress can improve the skill and non-skilled labor compensation by changing the labor productivity mode. Level, when the income level of individuals increases, they are more willing to accept higher education and become skilled workers, affecting the relative wage level of labor by changing the way labor supply. Among them, NCt is the intensity of the impact of neutral technological progress on relative wages. It is observed that the impact of neutral technological progress on relative wages is negative, and the intensity generally decreases with its level. 1 The process of the influence of neutral technological progress on relative wages and relative labor supply can be expressed as: initial neutral technological progress, the same proportion of wages for skilled labor and unskilled labor, the relative wages of the two remain temporarily unchanged. Due to the increase in labor income, people are more inclined to invest in higher education, which leads to an increase in the supply of skilled labor. The increase in supply has reduced the wages of skilled labor, that is, the effect of neutral technological progress has curbed the skill premium. And describes the changes in the period of neutral technological progress, the convergence of the relative wages of skilled and unskilled labor and the relative labor supply. It can be seen from the above that after 200 iterations, the relative wages and relative labor supply reach the new right of Table 3. The trend of relative wages and relative labor supply changes when neutral technological progress and biased technological progress change simultaneously. First, we find that the current trend of relative wages and relative labor supply is the same as when there is only biased technology, but the magnitude has changed. The result of the combination of the two technological advances is that the labor wage gap widens and the skill premium increases by 22%, albeit smaller than when there is only biased technological advancement, but contrary to the conclusion that there is only neutral technological progress. Secondly, the relative increase in labor supply exceeds the increase in the two technological advances alone, which shows that the two technological advances can increase the relative labor supply and can strengthen each other. Thirdly, observing the changes in the strength coefficients TCt and NCt of the two technological advances on relative wages, it is known that skill-biased and neutral technological advances have opposite effects on relative wages, that is, neutral technological advances help to suppress skill premiums. Skill-biased technological advancement has an expanding effect on the wage gap between skilled and unskilled labor, which can well explain the formation of current skill premiums. At the same time, the skill-biased technological advancement has a greater effect on labor compensation. If the technological progress is biased, the rewards of skilled labor and unskilled labor tend to progress and differentiate. This shows that if we can properly change the direction of technological progress, it will have an important impact on solving the problem of widening the current labor income gap. Finally, when both technological advances exist simultaneously, the relative wages and the convergence of the relative labor supply are seen. The convergence trend of relative wages is relative to the convergence trend of labor supply. The convergence trend of wages relative to the convergence trend of labor supply can be seen from the sum of the convergence trend and the similarity, but the fluctuation of relative wages and relative labor supply is larger. The convergence speed of its arrival equilibrium state is faster than that of only the advancement of biased technology and the progress of neutral technology. V. Basic conclusions Both empirical research pays more attention to the relationship between technological progress and labor compensation, does not pay attention to the internalization process of labor supply, the influence of technological progress direction and individual ability on educational choice, and the supply of labor to different types of technological progress. And the difference in the role of labor compensation. To this end, this paper introduces individual higher education choices, supplies skilled labor to internalization, uses mathematical models, explains the mechanism of technological progress bias on skill labor supply and skill premium, and combines the data of China's real society to examine the skills of technological progress. The bias and its impact on the skill premium simulate the evolution of labor supply and skill premium under different technological progress paths, and the following main conclusions are drawn. Individuals decide whether to accept higher education based on labor market information and their own abilities. The critical value is subject to the individual's expectation of future wages and labor supply time, while labor supply time and wages are affected by technical level. When the supply of skilled labor and unskilled labor remains unchanged, neutral technological advancement will increase the wages of skilled and unskilled labor in the same proportion, but has no effect on the wage ratio of the two, showing an unbiased character. The skill-biased technological advancement has a direct impact on the labor-wife ratio, that is, by increasing the wages of skilled labor versus unskilled labor, resulting in a skill premium, the strength of which depends on its own level and labor substitution elasticity.当技能劳动和éžæŠ€èƒ½åŠ³åŠ¨çš„供给内生å¯å˜æ—¶ï¼Œä¸æ€§å’ŒæŠ€èƒ½åå‘型技术进æ¥ï¼Œéƒ½ä¼šå¯¹æ•™è‚²é€‰æ‹©å’ŒæŠ€èƒ½åŠ³åŠ¨ä¾›ç»™äº§ç”Ÿå½±å“。åå‘型技术有助于æ高技能劳动工资，使个体选择高ç‰æ•™è‚²ã€‚而ä¸æ€§æŠ€æœ¯åˆ™åŒæ—¶æå‡æŠ€èƒ½ä¸ŽéžæŠ€èƒ½åŠ³åŠ¨çš„报酬，使个体在收入æ高åŽï¼Œæ›´æ„¿æ„接å—高ç‰æ•™è‚²ã€‚ è¿ç”¨2000å¹´ã€2004å¹´ã€2006å¹´å’Œ2009å¹´æ•°æ®æµ‹ç®—的结果显示，我国技术进æ¥æ£æœåå‘于技能劳动方å‘å‘展，且åå‘强度ä¸æ–å¢žåŠ ã€‚ä¸åŒç±»åž‹æŠ€æœ¯è¿›æ¥å¯¹æŠ€èƒ½æº¢ä»·çš„作用效果，å˜åœ¨æ˜Žæ˜¾å·®å¼‚。技能åå‘型技术进æ¥æ›´å€¾å‘于æå‡æŠ€èƒ½åŠ³åŠ¨ç”Ÿäº§çŽ‡ï¼Œæ‰©å¤§æŠ€èƒ½åŠ³åŠ¨å’ŒéžæŠ€èƒ½åŠ³åŠ¨çš„工资差è·ï¼Œè¯±å‘技能溢价。而ä¸æ€§æŠ€æœ¯è¿›æ¥çš„作用å´æ£å¥½ç›¸åï¼Œé€šè¿‡å¢žåŠ æŠ€èƒ½åŠ³åŠ¨ä¾›ç»™æ–¹å¼ï¼Œèƒ½å¤Ÿå‡å°æŠ€èƒ½åŠ³åŠ¨å’ŒéžæŠ€èƒ½åŠ³åŠ¨çš„工资差è·ã€‚一国是å¦å‡ºçŽ°æŠ€èƒ½æº¢ä»·ï¼Œå–决于两类ä¸åŒæ€§è´¨æŠ€æœ¯è¿›æ¥ä½œç”¨çš„相对强度。当å‰ï¼ŒæŠ‘制贫富差è·çš„扩大，除需调整居民收入的åˆæ¬¡åˆ†é…åŠå†åˆ†é…æ–¹å¼å’Œæ高劳动者技能水平外，政府还应关注ä¸åŒç±»åž‹æŠ€æœ¯è¿›æ¥ã€ç‰¹åˆ«æ˜¯ä¸æ€§æŠ€æœ¯è¿›æ¥å¯¹åŠ³åŠ¨æŠ¥é…¬çš„å½±å“，从技术进æ¥è§’度，缩å°åŠ³åŠ¨æ”¶å…¥åˆ†é…å·®è·ï¼Œä½¿æ‰©å¤§å†…需具有å¯æŒç»æ€§ã€‚ 〔责任编辑：æ¢åŽè´£ä»»ç¼–审：许建康〕8 ChoiceofEducation“；å¾èˆ’ã€æœ±å—苗：异质性è¦ç´ 回报ã€éšæœºå†²å‡»ä¸Žæ®‹andtheLaborMarket，â€vol.40，2002，pp.7-72；董直庆ã€çŽ‹èŠ³çŽ²ã€é«˜åº†æ˜†ï¼šæŠ€èƒ½æº¢ä»·æºäºŽæŠ€æœ¯è¿›æ¥åå‘性å—，6â‘ å…¬å¼ä¸º (Finish)
Description
Temporary Fence Also called temporary fence brace or stay used to support the temporary fence panel in
high wind area finish by hot dipped galvanized 42 microns thickness,per stay required two fence clamp and
three concrete feet the additional strength to secure fence panel stand well in high wind per 4.8meter or7.2 meter one stay live.
Specification
Panel: 2400mm*2100mm
Wire diameter: 4mm
Mesh size: 150*60mm
Pipe: 32mm*2mm
Hot-dipped galvanzied
Weight: 25kg
Panel size
2400mm(L)×2100mm(H),2100mm×2500mm
2100mm(H)×2650mm(L),2000mm(H)×3500mm(L)
Frame post
25mm,32mm,40mm,42mm,48mm
Infill mesh
2.5mm-6mm horizontal, 2.5mm-6mm vertical
50x50mm,50x100mm,50x200mm,75x150mm,60*150mm,50*150mm,100x300mm
Finish
pre-hot-dipped galvanized wire and tube then welded,or hot-dipped after welded
Application
Temporary Fencing to secure construction sites and private property;
Temporary fencing for major public events, sports, concerts, festivals, gatherings, swimming pools and other usages
Temporary fencing of residential housing sites;
The feet are removable which makes transportation and storage much easier and more efficient.
Environmentally friendly
The temporary fences is perfect for all surface as there are no holes to dig or repair.
Convenient
1. Temporary fences with chain link fence panels are a quick and convenient solution for a location or job site enclosure. Should access be required to anysection of the site
2. It is easily achieved by removing the appropriate panels, and either replacin the panels or adding extra panels when required.
Temporary Fence
Temporary Fence,Temporary Fencing,Temporary Construction Fence,Temporary Site Fencing
Anping Shengjia Hardware Mesh Co.,LTD , https://www.oilshaleshakerscreen.com