要旨：This paper revisits the core-periphery model of Krugman (1991) when his CES utility is replaced by a general additively separable sub-utility which captures the income effect and allows variable markups. New evolving paths and bifurcation patterns are created by the interaction between the agglomeration force generated by monopolistic competition, increasing returns to scale, trade cost and the dispersion force resulting from the pro-competitive effect. Autarky does not necessarily produce full dispersion and free trade may not correspond to agglomeration. Moreover, the demand parameter of manufactured goods is crucial to determining the firm location.

要旨：This talk will firstly review observed trends among public transport operators regarding fare polices and discuss that both simplification and “optimisation by differentiation” trends exist. If revenue and demand management optimal fares are desired, also in urban settings distance and route depending fares are increasingly an option due to new data collection technologies. This leads to modelling challenges such “hyperpaths with non-additive costs” which will be discussed in the second part. In the third part then the impact of new transport forms, in particular shared transport and “cheap taxis” is discussed. The competition and collaboration potential will be highlighted. The talk will close with some thoughts on how electrification of the transport system and vehicle to grid services might also impact fares and revenues.

論文ファイル

要旨：This paper explores how political, social, and economic regime changes affect the lifecycles of manufacturing plants, exploiting Japan’s transition from a feudal regime to a modern regime in the late nineteenth century as a natural experiment. Using plant-level data for 1902, including the foundation year of each plant, we explored how the experience years-size profiles of plants differ before and after the regime change. Plants were found to grow much faster after the regime change, and the acceleration of growth after the regime change was much greater for the plants in exporting industries and industries intensively using steam power. These findings suggest that access to markets and access to modern technologies were the channels through which the regime change affected the experience years-size profile of plants. Furthermore, long-term historical data and narratives on two plants support the results. We also present evidence on how the life-cycle size growth differs across space.

要旨：Pandemic of COVID-19 required to change our lifestyles to contain or mitigate the spread of infectious diseases. Various Non-pharmaceutical intervention (NPI) measures have been implemented in the situation that no effective treatment or vaccine has been established. New methods for monitoring the spread of infection have been proposed based on the recent technological and theoretical developments. In this talk, I review basics of mathematical models of infectious diseases and recent topics related with NPIs, and report and discuss some results on the effects of NPIs and the future perspective.

要旨：本研究は定量的空間経済モデル（quantitative spatial economics models）のパラメータを完全情報最尤推定（full information maximum likelihood, FIML）によって推定する新しい手法を提案する。内生変数の観測値から外生的な構造的残差（structural residuals）を一意に求められるモデルに対して、提案手法は適用可能である。構造的残差が確率分布に従うという仮定の下で、対数尤度関数を構築できる。提案手法は操作変数を必要としない。提案手法は、クロスセクションデータとパネルデータの双方に適用可能である。提案手法は、多くの場合において、パラメータの推定値を空間均衡が安定になる範囲に制約すると考えられる。本研究は、提案手法を二種類のデータに対して適用することにより、その有効性を確認する。一つ目は、既知のパラメータを有するモデルから発生させた実験データであり、二つ目は、1975年から2015年にかけての日本国内の観測データである。

要旨：Land is everywhere, being the substratum of our existence. In addition, land is intimately linked to the dual concept of location in human activity. Together, land and location are essential ingredients for the lives of individuals as well as for national economies. Today, there exist two different approaches to incorporating land and location into a general equilibrium theory. Dating from the classic work of von Thünen (1826), a rich variety of land-location density models have been developed. In a density model, a continuum of agents is distributed over a continuous location space. Given that simple calculus can be used in the analysis, these density models continue even today to be the “workhorse” of urban economics and location theory. However, the behavioral meaning of each agent occupying an infinitesimal “density of land” has long been in question. Given this situation, a radically new approach, called the σ-field approach, was developed in the mid 1980s for modeling land in a general equilibrium framework. In this approach: (i) the totality of land, L, is specified as a subset of R^2, (ii) all possible land parcels in L are given by the σ-field of Lebesgue measurable subsets of L, and (iii) each of a finite number of agents is postulated to choose one such parcel . Starting with Berliant (1985), increasingly more sophisticated σ-field models of land have been developed. Given these two different approaches to modeling land within general equilibrium framework, several attempts have thus far been proposed for bridging the gap between them. But while a systematic study of the relationship between density models and σ-field models remains to be completed, the clarification of this relationship could open a new horizon toward a general equilibrium theory of land.