Integration and Growth in East Asia

This paper empirically analyzes the experience of East Asiaf s economic growth with data both at aggregate-economy and micro-firm levels, focusing on the role of international integration through trade and direct investment. The analysis within a framework of cross-country panel regression shows that trade openness and foreign direct investment (FDI) inflows have a positive effect on GDP growth -particularly in the 1970s and 1980s- while FDI outflows appear to have a negative effect on GDP growth. Micro-level evidence based on manufacturing data in the Republic of Korea (Korea) confirms the positive effect of trade and investment integration on plant-level productivity growth. It also suggests that the relationship between FDI outflows and productivity growth depends on the characteristics of a recipient economy. We find that FDI to the Peoplefs Republic of China tends to reduce productivity growth of firms in Korea, while FDI to the United States or Japan works in favor of productivity growth.Integration; Growth; Trade; Foreign direct investment; East Asia

Economies of density versus natural advantage: crop choice on the back forty

We estimate the factors determining specialization of crop choice at the level of individual fields, distinguishing between the role of natural advantage (soil characteristics) and economies of density (scale economies achieved when farmers plant neighboring fields with the same crop). Using rich geographic data from North Dakota, including new data on crop choice collected by satellite, we estimate the analog of a social interactions econometric model for the planting decisions on neighboring fields. We find that planting decisions on a field are heavily dependent on the soil characteristics of the neighboring fields. Through this relationship, we back out the structural parameters of economies of density. Setting an Ellison-Glaeser dartboard level of specialization as a benchmark, we find that of the actual level of specialization achieved beyond this benchmark, approximately two-thirds can be attributed to natural advantage and one-third to density economies.

Multi Domain Semantic Information Retrieval Based on Topic Model

Over the last decades, there have been remarkable shifts in the area of Information Retrieval (IR) as huge amount of information is increasingly accumulated on the Web. The gigantic information explosion increases the need for discovering new tools that retrieve meaningful knowledge from various complex information sources. Thus, techniques primarily used to search and extract important information from numerous database sources have been a key challenge in current IR systems. Topic modeling is one of the most recent techniquesthat discover hidden thematic structures from large data collections without human supervision. Several topic models have been proposed in various fields of study and have been utilized extensively for many applications. Latent Dirichlet Allocation (LDA) is the most well-known topic model that generates topics from large corpus of resources, such as text, images, and audio.It has been widely used in many areas in information retrieval and data mining, providing efficient way of identifying latent topics among document collections. However, LDA has a drawback that topic cohesion within a concept is attenuated when estimating infrequently occurring words. Moreover, LDAseems not to consider the meaning of words, but rather to infer hidden topics based on a statisticalapproach. However, LDA can cause either reduction in the quality of topic words or increase in loose relations between topics. In order to solve the previous problems, we propose a domain specific topic model that combines domain concepts with LDA. Two domain specific algorithms are suggested for solving the difficulties associated with LDA. The main strength of our proposed model comes from the fact that it narrows semantic concepts from broad domain knowledge to a specific one which solves the unknown domain problem. Our proposed model is extensively tested on various applications, query expansion, classification, and summarization, to demonstrate the effectiveness of the model. Experimental results show that the proposed model significantly increasesthe performance of applications

Improved energy decay estimate for Dir-stationary QQ-valued functions and its applications

In this paper, we establish an improved decay estimate for the Dirichlet energy of Dir-stationary $Q$-valued functions. As a direct application of this estimate, we derive a Liouville-type theorem for bounded Dir-stationary $Q$-valued functions defined on $\mathbb{R}^m$. Additionally, in an attempt to establish the continuity of Dir-stationary $Q$-valued functions, we confirm that such functions exhibit the Lebesgue property at every point within their domain. Finally, we observe that the improved decay estimate implicates that Dir-stationary $Q$-valued functions reside within a generalized Campanato-Morrey space.Comment: All comments welcome

Quantum Phase Transitions and Dynamics in Perturbed Flatbands

In recent years, there has been a growing interest in flatband systems which exhibit macroscopic degeneracies. These systems offer a valuable mathematical framework for the extreme sensitivity to perturbations and interactions. This sensitivity unveils a wide variety of exotic and unconventional physical phenomena. Moreover, the progress in their experimental realization contributes to the expanding landscape of exploration in this field. This thesis aims to summarize all the works throughout the Ph.D. program. Firstly, an in-depth exploration was conducted on the impact of weak quasiperiodic perturbations on one-dimensional two-band all-bands-flat lattices. These tight-binding Hamiltonian are diagonalized through a sequence of local unitary transformations. By adjusting the quasiperiodic potential parameters, the key achievement involves finding a critical-to-insulator transition and identifying fractality edges in the flatband systems with quasiperiodic perturbations. Next, the investigation delved into the effects of on-site interactions among hard-core bosons in one- and two-dimensional cross-stitch lattices. One key finding is that groundstate energy primarily depends on compact localized states. Moreover, the presence of barriers of compact localized states trap bosons, leading to the emergence of non-ergodic excitation and Hilbert space fragmentation. Lastly, a compact localized eigenstate of the one-dimensional diamond chain using an electric circuit was successfully generated via local (linear and non-linear) driving. This achievement opens up a versatile circuit platform for the generation of flatbands and holds promise for potential applications in the field of quantum information. I hope these collective efforts have expanded the frontiers of the field and made a meaningful contribution to the scientific community.Comment: PhD thesis (2024 Feb.

Integration and Growth in East Asia

This paper empirically analyzes the experience of East Asiafs economic growth with data both at aggregate-economy and micro-firm levels, focusing on the role of international integration through trade and direct investment. The analysis within a framework of cross-country panel regression shows that trade openness and foreign direct investment (FDI) inflows have a positive effect on gross domestic product (GDP) growth? particularly in the 1970 and 1980s?while FDI outflows appear to have a negative effect on GDP growth. Micro-level evidence based on manufacturing data in the Republic of Korea (Korea) confirms the positive effect of trade and investment integration on plant-level productivity growth. It also suggests the relationship between FDI outflows and productivity growth depends on the characteristics of a recipient economy. We find that FDI to the Peoplefs Republic of China tends to reduce productivity growth of firms in Korea while FDI to the United States or Japan works in favor of productivity growth.integration, growth, trade, foreign direct investment, East Asia