Finding environmentally important industry clusters: Multiway cut approach using nonnegative matrix factorization

This paper proposes an optimal combinatorial method for finding groups of industries with relatively large CO₂ emissions through industrial relations. Using an economic input–output table, we estimated a non-symmetric matrix describing how much CO₂ is emitted in producing the commodity of industry i, which was purchased to produce commodity of industry j, to meet the final demand for a specific commodity. A symmetric strength of relations matrix describing the CO₂ emissions associated with the industrial relations was further estimated using the non-symmetric matrix. The strength of relations matrix can be viewed as a representation of the supply-chain network of the final commodity. In this study, we estimated the strength of relations matrix associated with the final demand for automobiles and applied the multiway cut approach using nonnegative matrix factorization to the matrix in order to find environmentally important industry clusters in the Japanese automobile supply chain. According to our empirical results, the optimal number of industry clusters is 19, and 4 industry clusters are playing a key role in CO₂ emission reduction.     

DELAY ESTIMATION BY A HILBERT TRANSFORM METHOD

This paper describes an estimation of the time delay between two stationary time series signals, in which an input signal is measured with little noise and an output signal is the sum of a noise and the response from a linear system. We use the Hilbert transform relation for minimum delay systems to estimate the time delay. Some computer simulation results are given to evaluate the performance of the proposed method.     

Supply Constraint from Earthquakes in Japan in Input–Output Analysis

Disasters often cause exogenous flow damage (i.e., the [hypothetical] difference in economic scale with and without a disaster in a certain period) to production (“supply constraint”). However, input-output (IO) analysis (IOA) cannot usually consider it, because the Leontief quantity model (LQM) assumes that production is endogenous; the Ghosh quantity model (GQM) is considered implausible; and the Leontief price model (LPM) and the Ghosh price model (GPM) assume that quantity is fixed. This study proposes to consider a supply constraint in the LPM, introducing the price elasticity of demand. This study uses the loss of social surplus (SS) as a damage estimation because production (sales) is less informative as a damage index than profit (margin); that is, production can be any amount if without considering profit, and it does not tell exactly how much profit is lost for each supplier (upstream sector) and buyer (downstream sector). As a model application, this study examines Japan's largest five earthquakes from 1995 to 2017 and the Great East Japan Earthquake (GEJE) in March 2011. The worst earthquake at the peak tends to increase price by 10–20% and decrease SS by 20–30%, when compared with the initial month's prices/production. The worst damage tends to last eight months at most, accumulating 0.5-month-production damage (i.e., the sum of [hypothetical] differences in SS with and without an earthquake [for eight months] is 50% of the initial month production). Meanwhile, the GEJE in the five prefectures had cumulatively, a 25-month-production damage until the temporal recovery at the 37th month.     

How to Get a Longer Job? Roles of Human and Social Capital in the Japanese Labor Market

This article investigates the roles of human and social capital played in the Japanese labor market. Our research question is whether they interact to accelerate or decelerate each other to provide first jobs of a long duration. Based on the literature, we focus on the bonding functions of friends and relatives. Using the 2005 Social Stratification and Social Mobility Survey Data, we measure human capital by educational attainment (college education) and social capital by job search methods (using friends or relatives). The dependent variable is the hazard rate of turnover from the first job. We find that social capital especially benefits those with low human capital (high school graduates). When friends or relatives introduce workers to jobs, high school graduates tended to stay longer in their first jobs and had a lower turnover than college graduates did. This means that social capital decelerated effects of human capital. Therefore, in the Japanese labor market, social capital plays a complementary role in mitigating educational disadvantage.     

Trade Linkages in Shrimp Exports: Japan,Thailand and Vietnam

Considerable attention has been devoted to the social and environmental consequences of shrimp farming in the tropics, but relatively little has been given to the relationships involved in international trade in processed shrimp. Based on extensive field research, this article addresses this gap in the literature by examining the nature of the linkages between Japan, a major importer, and two major exporting countries, Thailand and Vietnam, underlying which are informal agreements rather than formal contractual relationships. It examines the rationale and operation of such informal agreements in the context of a dynamic market characterised by an international division of labour between Thailand (with an advanced food products industry) and Vietnam (just emerging into the world market).