Cherry-Picking in Labor Market with Imperfect Information

We study a competitive labor market with imperfect information. In our basic model, the labor market consists of heterogeneous workers and ex ante identical firms who have only imperfect private information about workers' productivities. Firms compete by posting wages in order to cherry-pick more productive workers from the applicant pool. The model predicts many important empirical regularities, including non-degenerated firm size distribution, persistent wage dispersion, and employer size-wage premium. We also consider extensions of the model where firms differ in either productivity or information about worker types, both generating assortative matching with a positive but imperfect correlation of worker and firm types. The main insight of this paper is that identical workers can get different wages depending on productivities of their coworkers in a competitive market with informational frictions. Our model also sheds light on inter-industry wage differential and sorting between industry and worker characteristics.imperfect information, cherry-picking, wage dispersion, size-wage premium, inter-industry wage differential

Study on Temperature Control and Crack Prevention of Mass Concrete for Large Powerhouse Constructed in Cold Area

Due to complex structure, large scale, and cold climate, the temperature field and stress field during construction of BoYi Station is different with ordinary mass concrete. Therefore the corresponding crack prevention method must be explored. In order to simulate the complicated construction course, cold climate, multiple materials and unusual structure, a finite element program is adopted. In 5 numerical simulation cases, different temperature control methods are tried to decrease the tensile stress of mass concrete. Based on the simulation analysis and combined with the engineering experience, the scheme and indexes of temperature control and crack prevention are recommended. The mainly measures are controlling pouring temperature, insulation of concrete surface, pipe cooling, block partition and extra steel bar reinforcement. The values of temperature indexes are sharply lower than that of ordinary hydropower station mass concrete. The suggested measures and indexes in this paper, which are various with season, structure position and material, may provide some reference to similar large hydropower station workshop in cold area

Approximate efficiency in repeated games with correlated private signals

This paper presents repeated games with hidden moves, in which players receive imperfect private signals and are able to communicate. We propose a conditional probability approach to solve the learning problem in repeated games with correlated private signals and delayed communication. We then apply this approach to symmetric n-player games to obtain an approximate efficiency result.

Moral hazard, insurance claims, and repeated insurance contracts

The paper develops a simple model of repeated automobile insurance contracts, providing a framework for analyzing changes in aggregate insurance data in periods of changes that affect driver incentives. Experience rating of premiums gives drivers an incentive to exert effort to avoid accidents (ex ante moral hazard), and an incentive to hide accidents (ex post moral hazard). The empirical analysis, using data from the competitive insurance markets in Ontario and Alberta over a period of major legislative changes in Ontario, suggests that much of the recent decline in accidents in Ontario was due to an increased incentive to hide accidents.

Forecasting regional income inequality in China

In this study, the mathematical models with Gini coefficients and variation coefficients are used to study the time-series properties of China’s regional income differences. The result shows that from 1952 to 1978 the differences increase; from 1978 to the beginning of 1990s decrease; and from the beginning of 1990s to 1995 increase a little. In addition, the multi-level autoregressive models with time-varying parameters are used to predict the differences of China’s regional per capita income from 1996 to 2000. The per capita income levels of various regions in China have also been forecasted by using adaptive control algorithms to depict an acceptable level of income inequality for policy making

Study on Temperature Control and Crack Prevention of Mass Concrete for Large Powerhouse Constructed in Cold Area

Due to complex structure, large scale, and cold climate, the temperature field and stress field during construction of BoYi Station is different with ordinary mass concrete. Therefore the corresponding crack prevention method must be explored. In order to simulate the complicated construction course, cold climate, multiple materials and unusual structure, a finite element program is adopted. In 5 numerical simulation cases, different temperature control methods are tried to decrease the tensile stress of mass concrete. Based on the simulation analysis and combined with the engineering experience, the scheme and indexes of temperature control and crack prevention are recommended. The mainly measures are controlling pouring temperature, insulation of concrete surface, pipe cooling, block partition and extra steel bar reinforcement. The values of temperature indexes are sharply lower than that of ordinary hydropower station mass concrete. The suggested measures and indexes in this paper, which are various with season, structure position and material, may provide some reference to similar large hydropower station workshop in cold area