要旨：I propose a model with multiple cities that allows inter-city interactions through costly trade, internal migrations, and firm relocation. The model features multiple sectors, heterogeneous firms, and heterogeneous workers. The comparative statics of the model focuses on three shocks: falling transport costs, declining education costs, and increasing high-skill intensities. I show that: (1) there is a non-monotonic relationship between transport costs and the spatial income inequality; (2) a structural transformation triggered by declining education costs reduces the inequality, (3) the one due to a skill-biased technological change, however, predicts the opposite. The theoretical predictions are confirmed by a panel regression using the data from 32 countries with 1,962 regions.

要旨：This paper shows evidence for a microeconomic mechanism of collaborative knowledge creation proposed by Berliant and Fujita (2008) using the panel data of patent development in Japan. Researchers communicate via common knowledge, and innovate by utilizing differentiated knowledge of each other. A longer duration of collaboration between a pair of researchers increases their common knowledge which at the same time accumulates differentiated knowledge between them and the rest of the researchers. Facing polyadic interactions, individual researchers collectively determine the set of collaborators to interact, and hence the fraction of time a researcher spends with each of her collaborators, so as to optimize the composition of common and differentiated knowledge between a given researcher and each of her collaborators. We also show additional evidence for creative destruction, positive influence of local spillovers as well as transport accessibility.

要旨：Observing rapid structural transformation accompanied by a continual process of rural to urban migration in many developing countries, we construct a micro founded dynamic framework to explore how important education-based migration is, as opposed to work-based migration, for economic development, urbanization and city workforce composition. We then calibrate our model to fit the data from China over the period from 1980 to 2007, a developing economy featuring not only large migration flows but major institutional reforms that may affect work and education based migration differently. We find that, although education-based migration only amounts to one-fifth of that of work-based migration, its contribution to the enhancement of per capita output is larger than that of work-based migration. Moreover, the abolishment of the government job assignment for college graduates and the relaxation of the work-based migration have limited effects on economic development and urbanization. Furthermore, the increase in college admission selectivity for rural students plays a crucial but negative role in China's development, lowering per capita output and worsening the high-skilled employment share in urban areas.

要旨：The purpose of this study is to examine applicability of agglomeration effect on tourism economics. For this purpose, this study test the hypothesis that tourists have "love of variety''. To test the hypothesis, we suggest a theoretical model of tourists' destination choice, which is based on the Dixit-Stiglitz model of monopolistic competition. We test the hypothesis using data on five residential countries and nine destination countries in the EU. The results show the number of firms in the destination affects the tourists' destination choice. In other words, tourists' preference exhibits love of variety. Hence, the theory of agglomeration can apply to tourism economics.