要旨：There is increasing empirical evidence that vertical product differentiation is an important determinant of international trade. However, the economic literature so far has solely focused on the case in which quality trade stems from differences between countries. No studies investigate the role of quality trade between similar economies. This paper first develops a simple theoretical trade model that includes vertical product differentiation in a heterogeneous-firm framework. The model yields three main predictions for trade between similar economies. First, exported goods are of higher quality than goods sold on the domestic market. Second, larger economies have on average higher export qualities compared with smaller economies. Third, with increasing trade costs higher quality goods are exchanged. For all three effects, strong empirical support is found using detailed export trade data of the United States and 15 European Union countries.

要旨：This paper aims to address the effects of congestion externalities in a new economic geography context. Our model is the same as the standard CP model except for the assumption that per-unit interregional transport cost depends on total volume of shipped varieties. As a result of the endogeneity of per-unit transport cost, we have some features of agglomeration and dispersion equilibria that are not evident from the standard models. A welfare analysis focuses on a second best problem so that a market still can take a part in generating agglomeration economies. That is, we investigate the relationship between the congestion externalities and the second best unit tax of shipped goods given firm's monopolistic pricing. If skilled workers are nearly agglomerated in one region, the interregional congestion externalities should not be fully internalized regardless of the level of transport technology. In an evenly dispersed economy, however, the second best tax can be larger than the congestion externalities if the level of transport technology is low.

要旨：Using a simple North-South trade model with vertically related markets, we show that a North downstream firm may have an incentive to strategically utilize technology spillovers to a local rival caused by foreign direct investment (FDI). Whether the North firm invests in the South depends on the South firm's capacity to absorb the North technology. FDI arises only if the capacity is medium. Technology spillovers through FDI may benefit all producers and consumers. Our analysis also suggests that very tight intellectual property rights protection in the South may benefit neither the North nor the South, because it "discourages" FDI.

マセマティカル・モルフォロジは，鉱物の画像処理による分析の試みがきっかけとなり，画像中の図形のもつ構造を記述するための数学的枠組みとして，約40年前に創始された．その後，さまざまな分野での定量的画像演算の枠組みとして発展している一方で，数学的には束における演算の体系として定式化され，画像処理以外での分野での応用が開けてきている．本講演では，マセマティカル・モルフォロジの基本的概念・演算の構成について説明する．また，講演者のグループの研究から，テクスチャ解析・医用画像処理といった画像処理の研究，さらにその他の応用について紹介する．