Horizontal and Vertical Polarization

We analyze the effect of technological change in a novel framework that integrates an economy's skill distribution with its occupational and industrial structure. Individuals become managers or workers based on their managerial vs. worker skills, and workers further sort into a continuum of tasks (occupations) ranked by skill content. Our theory dictates that faster technological progress for middle-skill tasks not only raises the employment shares and relative wages of lower- and higher-skill occupations among workers (horizontal polarization), but also raises those of managers over workers as a whole (vertical polarization). Both dimensions of polarization are faster within sectors that depend more on middle-skill tasks and less on managers. This endogenously leads to faster TFP growth of such sectors, whose employment and value-added shares shrink if sectoral goods are complementary (structural change). We present several novel facts that support our model, followed by a quantitative analysis showing that task specific technological progress|which was fastest for occupations embodying routinemanual tasks but not interpersonal skills|is important for understanding changes in the sectoral, occupational, and organizational structure of the U.S. economy since 1980

Probing nucleon strangeness in phi electroproduction

We investigate $\phi$ meson electroproduction to probe the hidden strangeness content of the nucleon. We found that even a small amount of the $s\bar{s}$ admixture in the nucleon wavefunction can lead to a significant change in several double polarization asymmetries in $\phi$ electroproduction, which can be tested experimentally at current electron facilities.Comment: 3 pages, 1 figure (2 eps files), LaTeX2e with espcrc1.sty, Talk at the XVI International Conference on Few-Body Problems in Physics (FB16), Taipei, Taiwan, March 6-10, 200

Computerizing Industries and Routinizing Jobs: Explaining Trends in Aggregate Productivity

Aggregate productivity growth in the U.S. has slowed down since the 2000s. We quantify the importance of differential productivity growth across occupations and across industries, and the rise of computers since the 1980s, for the productivity slowdown. Complementarity across occupations and industries in production shrinks the relative size of those with high productivity growth, reducing their contributions toward aggregate productivity growth, resulting in its slowdown. We find that such a force, especially the shrinkage of occupations with above-average productivity growth through \routinization," was present since the 1980s. Through the end of the 1990s, this force was countervailed by the extraordinarily high productivity growth in the computer industry, of which output became an increasingly more important input in all industries (\computerization"). It was only when the computer industry's productivity growth slowed down in the 2000s that the negative effect of routinization on aggregate productivity became apparent. We also show that the decline in the labor income share can be attributed to computerization, which substitutes labor across all industries

Productivity Growth and Capital Flows: The Dynamics of Reforms

Why doesn’t capital flow into fast-growing countries? In this paper, we provide a quantitative framework incorporating heterogeneous producers and underdeveloped domestic financial markets to study the joint dynamics of total factor productivity (TFP) and capital flows. When an unexpected once-and-for-all reform eliminates non-financial distortions and liberalizes capital flows, the TFP of our model economy rises gradually and capital flows out of it. The rise in TFP reflects efficient reallocation of capital and talent, a process drawn out by frictions in domestic financial markets. The concurrent capital outflows are driven by the positive response of domestic saving to higher returns, and by the sluggish response of domestic investment to the higher TFP—the latter being another ramification of domestic financial frictions. We use our model to analyze the welfare consequences of opening up capital accounts. We find that the marginal welfare effect of capital account liberalization is negative for workers and positive for entrepreneurs and wealthy individuals.

Probing nucleon strangeness structure with phi electroproduction

We study the possibility to constrain the hidden strangeness content of the nucleon by means of the polarization observables in phi meson electroproduction. We consider the OZI evading direct knockout mechanism that arises from the non-vanishing s\bar{s} sea quark admixture of the nucleon as well as the background of the dominant diffractive and the one-boson-exchange processes. Large sensitivity on the nucleon strangeness are found in several beam-target and beam-recoil double polarization observables. The small \sqrt{s} and W region, which is accesible at some of the current high-energy electron facilities, is found to be the optimal energy region for extracting out the OZI evasion process.Comment: 8 pages, LaTeX2e, elsart.cls, 3 figures (4 eps files

Interactive plant simulation modeling for developing an operator training system in a natural gas pressure-regulating station

Abstract This study proposes a method of interactive plant simulation modeling which delivers the online simulated results to the field operators and induces them to take proper actions in the case of pre-identified accident scenarios in a chemical plant. The developed model integrates the real-time process dynamic simulation with 3D-CFD accident simulation in a designed interface using object linking and embedding technology so that it can convey to trainees the online information of the accident which is not available in existing operator training systems. The model encompasses the whole process of data transfer till the end of the training at which a trainee operates an emergency shutdown system in a programmed model. In this work, an overall scenario is simulated which is from an abnormal increase in the main valve discharge (second) pressure due to valve malfunction to accidental gas release through the crack of a pressure recorder, and the magnitude of the accident with respect to the lead time of each trainees emergency response is analyzed. The model can improve the effectiveness of the operator training system through interactively linking the trainee actions with the simulation model resulting in different accident scenarios with respect to each trainees competence when facing an accident.This research was supported by a Grant No. (14IFIP-B085984-03) from Smart Civil Infrastructure Research Program funded by the Korea Government Ministry of Land, Infrastructure and Transport (MOLIT) and The Korea Agency for Infrastructure Technology Advancement(KAIA), and by Korea Ministry of Environment (MOE) as the Chemical Accident Prevention Technology Development Project (No. 2015001950003)