【Paper】5/1改訂版　【資料】5/16掲載　【Slide】5/17掲載

Abstract: Knowledge creation either in isolation or joint with another person, using either face to face or internet contact and incorporating internet search ability is analyzed. Both a conceptual phase and a technical phase of research are analyzed, allowing workers to choose endogenously their mode of communication. In addition to formal knowledge, tacit knowledge plays an essential role in the knowledge production process, as it is not internalized. Lead time for face to face communication plays a key role. The sink point is inefficient. Our framework is applied to pandemic restrictions on face to face communication.

【Paper】【Slides】(5/5更新)

Abstract: Urban informality, which is prevalent in Africa’s rapidly growing cities, can reduce private investments, lower tax bases, and exacerbate urban disamenities. A key policy tool to address this problem is greenfield urban planning where governments purchase cheap agricultural land on the urban fringe and partition it into planned, surveyed, and titled de novo plots, which people can purchase and build houses on. Yet, there is very little systematic evidence on the effects of de novo planning choices, such as the size and configuration of residential and non-residential plots. We study the consequences of such planning decisions in Tanzania’s “20,000 plot” project, which provided over 36,000 residential plots in 12 project areas on the fringes of Dar es Salaam in the early 2000s. We study this project using detailed maps, questionnaires, and satellite imagery, and we combine within-neighborhood analysis and spatial regression discontinuity designs. We find that overall, the project secured property rights and access, thus boosting land values, and attracting highly educated owners; small plots, which command higher land values and are built more intensively, are under-provided; access to main paved roads is prized; and development rates are higher where plot layout is more gridded and small plots are bunched together. But planned non-residential amenities are ignored due to low implementation rates and about half the plots are still unbuilt, suggesting that despite the project’s success, significant improvements are possible.

【スライド】

要旨：本講義では、ネットワーク上の行動のモデリングについて、主に交通分野の経路選択行動分析における経路相関，経路選択肢集合の特定、エージェント間の相互作用（交通混雑）という3つのモデリング上の課題に着目しながら、方法論的発展を概説します。また、それらを同時に解決するマルコフ型ネットワーク均衡モデルや、モデル推定に関する数値計算問題への対処、そして局所的な反応を同時に扱うモデルなど、発表者の近年の取り組みについても紹介し、ネットワーク行動モデルの可能性について議論します。

《参考文献》

Oyama, Hara and Akamatsu, Transportation Research Part B: Methodological, 2022

Oyama, Transportation Research Part C: Emerging Technologies, 2023

Oyama, Transportation Research Part A: Policy and Practice, 2024

【論文】 【スライド】

要旨：Labor force participation of prime-aged males in the U.S. has secularly declined for a half century since 1970s, threatening the formation of partnership and fertility. I test a hypothesis that long-run climate change nudged their labor market exits, a significant fraction of whom are working outdoors under heightened exposure to hot days. Combining granular daily temperature data and labor force participation across U.S. Commuting Zones during 1970-2019, I find that accumulated exposure to hot day with mean temperature 80F accounts for 20-30% of increased non-participation of prime-aged males. Climate change significantly accounts for market exits of black males, historically agglomerated in the Southeast, where warming was severest.

要旨：Young women outnumber young men in cities in many countries during periods of economic growth and urbanization. This gender imbalance among young urbanites is more pronounced in larger cities. We use the gradual rollout of special economic zones across China as a quasi-experiment to establish the causal impact of urbanization on gender-differential incentives to migrate. Our analysis suggests that a plausible explanation is rural women’s higher likelihood of marrying and marrying up in cities during rapid urbanization.