Challenging the Non-Native English Speaker Identity in U.S. Higher Education: A Case of International Graduate Students

The present study is grounded in the theoretical understanding of U.S. graduate- level classes as a community of practice and the poststructuralist understanding of language use and identity. In this study, I use a questionnaire and semi- structured interviews to explore how graduate students—both native and non- native English-speaking—perceive their own and others’ participation in class discussions. Also, with a focus on their identity negotiated during their class interactions, I examine possible unequal power relations in graduate classrooms. The results showed that the native students had negative attitudes toward non-native students’ participation, most participants felt that unequal power relations exist in classroom communities, and some non-native students felt marginalized in the classroom. Lastly, some suggestions are presented to bring about equal positioning and harmony in graduate classroom communities

Essays on prices and frictions

This dissertation consists of three essays on prices and frictions. The first chapter documents cyclical properties of distributions of labor factor prices, wages, in the United States from 1979 to 2016. The second chapter investigates which theory of nominal wage frictions in the existing literature has consistent implications with empirical regularities documented in the first chapter. The third chapter estimates the impact of e-commerce, a recent technology innovation reducing information frictions and trade costs, on prices and welfare in Japan. In Chapter 1, I construct distributions of individual workers’ year-over-year changes in nominal hourly wages across time and across US states from two nationally representative household surveys, the Current Population Survey (1979-2017) and the Survey of Income and Program Participation (1984-2013). The novel result is that the share of workers with no wage changes, which accounts for the large spike at zero in nominal wage change distribution, is more countercyclical than the share of workers with wage cuts. A strand of related literature interpreted the empirical finding that US states with larger decreases in employment are also the states with lower average wage increases as a sign of wage flexibility. This paper overturns this interpretation by showing that the states with larger employment declines are also the states with greater increases in the share of workers with a zero wage change, suggesting wage rigidity instead. In Chapter 2, I ask which type of nominal wage rigidity model in the existing literature can match empirical regularities documented in Chapter 1. This chapter builds heterogeneous agent models with five alternative wage-setting schemes—perfectly flexible, Calvo, long-term contracts, menu costs, and downward nominal wage rigidity. The models feature not only idiosyncratic uncertainty but also aggregate uncertainty. Using a numerical method, I show among alternative wage setting schemes, the model with downward nominal wage rigidity has the most consistent implications with the empirical findings, regarding the shape and cyclicality of wage change distributions. In Chapter 3, joint work with Misaki Matsumura and David Weinstein, we estimate the impact of e-commerce on Japanese prices and welfare. We find that goods sold intensively online have always had lower relative rates of price increase than goods sold mainly in physical stores, but the gap in inflation rates rose after the advent of e-commerce. This happened in part because goods sold offline began experiencing faster rates of price increase. Second, we compute the welfare gains generated by e-commerce by reducing intercity price differentials and by increasing available varieties. While we show the national gains were substantial, we also find that welfare rose much more for residents of high-income cities with highly educated populations and may have fallen for residents of other cities

Hodge ideals and spectrum of isolated hypersurface singularities

We introduce Hodge ideal spectrum for isolated hypersurface singularities to see the difference between the Hodge ideals and the microlocal $V$-filtration modulo the Jacobian ideal. Via the Tjurina subspectrum, we can compare the Hodge ideal spectrum with the Steenbrink spectrum which can be defined by the microlocal $V$-filtration. As a consequence of a formula of Mustata and Popa, these two spectra coincide in the weighted homogeneous case. We prove sufficient conditions for their coincidence and non-coincidence in some non-weighted-homogeneous cases where the defining function is semi-weighted-homogeneous or with non-degenerate Newton boundary in most cases. We also show that the convenience condition can be avoided in a formula of Zhang for the non-degenerate case, and present an example where the Hodge ideals are not weakly decreasing even modulo the Jacobian ideal.Comment: 29 page

A Meta-Analysis of Ethical Fashion Consumption Research in South Korea

In this study, a meta-analysis of studies on ethical fashion consumption in South Korea was conducted with the purpose of better understanding the influences of different factors on ethical fashion consumption

Mass Spectra Prediction with Structural Motif-based Graph Neural Networks

Mass spectra, which are agglomerations of ionized fragments from targeted molecules, play a crucial role across various fields for the identification of molecular structures. A prevalent analysis method involves spectral library searches,where unknown spectra are cross-referenced with a database. The effectiveness of such search-based approaches, however, is restricted by the scope of the existing mass spectra database, underscoring the need to expand the database via mass spectra prediction. In this research, we propose the Motif-based Mass Spectrum Prediction Network (MoMS-Net), a system that predicts mass spectra using the information derived from structural motifs and the implementation of Graph Neural Networks (GNNs). We have tested our model across diverse mass spectra and have observed its superiority over other existing models. MoMS-Net considers substructure at the graph level, which facilitates the incorporation of long-range dependencies while using less memory compared to the graph transformer model.Comment: 19 pages, 3figure