要旨：When making a location decision, a firm considers only its own trading costs and ignores trading costs paid by trading partner firms. The exclusion of the latter is the source of locational externalities. We examine this locational externality in the Tokyo metropolitan area, using the actual trade networks. Results show (1) we classify what trade patterns involve locational externalities, (2) the ratio of trades involving locational externalities is about 8%, and (3) the transfer of a randomly-chosen 5% of firms to the center of Tokyo can generate external benefits of 0.13-0.21% in the total industry in terms of value added.

要旨：High-speed rail integrates regions and cities, and thus can possibly have significant impacts on the distribution of economic activities. Using the opening and extensions of a high-speed rail, Shinkansen, in Kyushu, Japan, we examine its effects on the distribution of economic activities across urban agglomerations. We focus on changes in land prices and estimate hedonic price equations to conduct a difference-in-difference analysis. We find that the large metropolitan areas gained from the high-speed rail by experiencing increases in land prices, whereas small metropolitan areas located between them lost by experiencing decreased land prices. However, such positive effects are shown to be limited to areas close to Shinkansen stations.

要旨：We study the effect of natural disasters on port level exports. We model the interaction between firms and ports to study how strongly exports from one port are affected by changes in the cost of exporting at neighboring ports. We extend the standard trade model with heterogeneous firms to a multiple port structure where exporting is subject to port specific local transportation costs, port specific fixed export costs and international bilateral trade costs. We show that gravity distortion due to firm heterogeneity is conditional on the comparative advantage at the port level and resulting substitution of exports across ports. We present evidence of the substitution effect using the 2011 Great East Japan Earthquake, indicating that at least 40% of exports was substituted to other ports following the disaster. The substitution effects is strongest in technology intensive product categories, which suggests an interaction between supply chains and domestic trade costs.

要旨：Cities and roads are the fundamental infrastructures that human society has developed. Their organizations are complex phenomena involved with many natural and social factors: business, commerce, transport, politics, diplomacy, culture, landscape, climate, hydrosphere, natural resources, etc. Geographical landscape appears to be the key factor among them, but most previous modelling studies assumed an ideally homogeneous space because of so-called `for the sake of simplicity'. Here we propose a working hypothesis that co-evolving dynamics of cities and roads defined on the space of geographical landscapes reproduce the outline of real-world spatial patterns of them. To examine this hypothesis, using high resolution digital topographic databases, we evaluate the distance between locations on the natural terrains by least cost path analysis, and define a dynamical system of the cites and roads on the evaluated space, and compare the stationary state of the system with a census. In a preliminary work on Hokkaido region in Japan, we found that the integration of the natural geographical factors leads to the emergence of comparable spatial patterns to the real one, while the model also reproduces the regularly spaced, lattice-like pattern of cities as the same as the previous models on an ideally homogeneous space with a homogeneous city-size distribution. This result indicates that the natural landscape factors have important relevance on the spatial distribution of populations.

要旨：In the early 20th century, the British Empire primarily governed South Asia, and these regions shared similar administrations, institutions and commercial practices. After the Second World War, decolonization in South Asia became evident through the partition of India and countries gaining independence. These subsequent events can be seen as regional disintegration, and they offer a potential scope for examining the impacts of such institutional changes on maritime transport networks. By examining a new database detailing vessel movement between South Asian ports and the rest of the world from 1890 to 2000, we explore how maritime transport networks evolved in South Asia. Specifically, we compare the trends of shipping routes among ports before and after 1947. Applying the methodology developed by Redding, Sturm, and Wolf (2011) and Xu and Itoh (2017), we show that regional disintegration clearly lowered vessel movements for the routes that became international after 1947. Additionally, we examine two points; relationship with UK, and the independence of Bangladesh. For most of the cases, we find significantly negative impacts on vessel movements directly affected by regional disintegration.