The Integrative Functions of Post-industrial U.S. Labor Market for Marriage Formation: Three Essays

The deteriorating labor market position of young men has arguably played an important role in later and less frequent marriage since the 1970s. This dissertation examines the relationship between men’s socioeconomic characteristics and marriage formation and the labor market causes of marriage declines since the 1970s. It is motivated by three aspects of labor market changes that have characterized the post-industrial U.S. economy: the historic shift in labor market returns to schooling, women’s occupational integration and changes in men’s career entry. I find that: (1) Erosion in the employment opportunities of noncollege educated black men is partly responsible for their faster rate of marriage decrease. The effect of employment on educational differences in marriage trends is small for whites. For both races, educational differences in the trends toward lower marriage rates primarily arise from an economy-wide wage structure change that increasingly decreases wages of noncollege educated men. (2) Women’s occupational integration has a positive effect on men’s likelihood of marrying women employed in the same occupation, but a negative effect on men’s likelihood of marrying women employed in different occupations. The negative relationship between the female proportion in an occupation and the likelihood of marrying for male workers is partly attributable to the marriage disincentives of underemployment and lower wages. On the whole, although working in more female occupations facilitates men’s marriage formation, the effect is small and cannot compensate for the marriage disincentives of underemployment and lower wages when men work in more female intensive occupations. (3) Increased difficulties the recent cohort of noncollege educated men have encountered in career entry play an important role in marriage declines among them. For the recent cohort of men with some college education, however, marriage declines are mainly due to their extended patterns of school attendance. The recent cohort of college men also delayed marriage, but their marriage delays are not related to changes in career entry. For both college and noncollege educated men, marriage declines since the 1970s also reflect a shift in the economic foundations of marriage formation

Optimal Modeled Six-Phase Space Vector Pulse Width Modulation Method for Stator Voltage Harmonic Suppression

Dual Y shift 30 six-phase motors are expected to be extensively applied in high-power yet energy-effective fields, and a harmonic-suppressing control strategy plays a vital role in extending their prominent features of low losses and ultra-quiet operation. Aiming at the suppression of harmonic voltages, this paper proposes a six-phase space vector pulse width modulation method based on an optimization model, namely OM-SVPWM. First, four adjacent large vectors are employed in each of 12 sectors on a fundamental sub-plane. Second, the optimization model is constructed to intelligently determine activation durations of the four vectors, where its objective function aims to minimize the synthesis result on a harmonic sub-plane, and its constraint condition is that the synthesis result on the fundamental sub-plane satisfies a reference vector. Finally, to meet the real-time requirement, optimum solutions are obtained by using general central path following algorithm (GCPFA). Simulation and experiment results prove that, the OM-SVPWM performs around 37% better than a state-of-the-art competitive SVPWM in terms of harmonics suppression, which promise the proposed OM-SVPWM conforms to the energy-effective direction in actual engineering applications.Peer reviewe