Population and Urbanization Trends in Post-war Japan

This paper analyses the population change and urbanization process in post-war Japan. We trace the process of population concentration into urban areas, in parallel with economic development after the war. The concentration of population into urban areas can be characterized by three major metropolitan regions: Tokyo, Keihanshin (Kyoto-Osaka-Kobe) and Nagoya. We also show that the urbanization process of Japan in the period from 1965 to 1985 can be characterized by two spatial phenomena; firstly, the suburbanization of the existing metropolitan areas and, secondly, the spatial dispersal of urbanized areas.     

Firm-specific volatility of stock returns, the credibility of management forecasts, and media coverage: Evidence from Japanese firms

This paper explores the determinants of firm-specific informativeness of the stock price in terms of corporate disclosure quality and the quantity of public information by using Japanese data. In our empirical framework, we examine how the credibility of disclosure and media coverage are associated with the firm-specific volatility of stock returns. The results indicate that both greater accuracy of management forecasts and greater total media coverage contribute to the incorporation of firm-specific information in the stock price. Furthermore, for earnings-related news, the media reporting leads to less firm-specific volatility. Finally, an improvement in forecast accuracy enhances the marginal effect of media coverage of the earnings news toward reflecting firm-specific information.     

A Taxi Zoning Analysis Using Large-Scale Probe Data: A Case Study for Metropolitan Bangkok

Taxis are considered one of the most convenient means of transportation, especially when people have to travel off-route, where public transportation is not a feasible option, and also when they need to reach a destination according to what is most convenient for them. However, many issues exist about taxi services, such as the problems of passengers who are unable to get taxi service at the location of their choice, or problems concerning when they need the taxi service to arrive. These problems may be due to the unavailability of the taxi at that particular location or due to the taxi driver not wanting to provide service. A taxi driver may not want to provide service to a potential passenger, because they may have preferences on the direction and areas they want to go or because of the different types of service zoning. Understanding the behaviors of taxi drivers and the characteristics of the trip/travel might be helpful to solving such issues. In this study, we conducted an analysis from a questionnaire survey and large-scale taxi probe data to understand taxi service behavior, travel characteristics, and to discover taxi service zoning characteristics. As a result, four types of taxi service zones including isolated zones, interactive zones, special service zones, and target zones were encountered. Travel characteristics were calculated and analyzed at different criteria, such as weekdays, weekends, and various time windows in a single day. The result of these characteristics was explained according to their similarities and dissimilarities in each type of zone. The discovery of the different zones and their respective definitions might be a good initiative for further development of a policy for taxi drivers to provide better service for passengers.     

Matrix exponential GARCH

I propose a new multivariate GARCH specification that maintains positive definiteness of the conditional covariance matrix. The idea is to specify the dynamics in the matrix logarithm of the conditional covariance. Because the matrix exponential transformation ensures positive definiteness, the dynamics can be specified without the positive definiteness constraint. This affords a variety of specifications and, in particular, we can specify element-by-element the dynamics of the matrix logarithm. I discuss specifications with leverage effects, estimation with multivariate Gaussian and t-distributions, and diagnostics that evaluate the appropriateness of the matrix exponential specification.     

Foreign direct investment,international trade,and firm heterogeneity

We present an asymmetric model with firm heterogeneity and foreign direct investment (FDI) from a developed country to a developing country. We found that the successful entry firms could be sorted from highest to lowest according to productivity as reimport firms, FDI firms, export firms, and domestic firms. We also found that FDI decreases (increases) the gross national income of the developed (developing) country, but it can either increase or decrease the world income according to the level of the relative propensity to spend. In addition, we demonstrated that FDI influences welfare through variations in average price, national income, and the number of types of goods.     

Estimation of Discrete Choice Dynamic Programming Models

This study reviews estimation methods for the infinite horizon discrete choice dynamic programming models and conducts Monte Carlo experiments. We consider: the maximum likelihood estimator (MLE), the two‐step conditional choice probabilities estimator, sequential estimators based on policy iterations mapping under finite dependence, and sequential estimators based on value iteration mappings. Our simulation result shows that the estimation performance of the sequential estimators based on policy iterations and value iteration mappings is largely comparable to the MLE, while they achieve substantial computation gains over the MLE by a factor of 100 for a model with a moderately large state space.