CCSS International Workshop on Computational Social Science

13:00～13:10　開会挨拶 / Opening Remarks

上東　貴志（神戸大学計算社会科学研究センター長）

13:15～13:50

論題
Topic

Does the Supply Network Shape the Firm Size Distribution? The Japanese Case

報告者
Presenter

Corrado DI GUILMI（University of Technology Sydney）

概要
Abstract

The paper presents an investigation on how the upward transmission of demand shocks in the Japanese supply network influences the growth rates of firms and, consequently, shapes their size distribution. Through an empirical analysis, analytical decomposition of the growth rates' volatility, and numerical simulations, we obtain several original results. We find that the Japanese supply network has a bow-tie structure in which firms located in the upstream layers display a larger volatility in their growth rates. As a result, the Gibrat's law breaks down for upstream firms, whereas downstream firms are more likely to be located in the power law tail of the size distribution. This pattern is determined by the amplification of demand shocks hitting downstream firms, and the magnitude of this amplification depends on the network structure and on the relative market power of downstream firms. Finally, we observe that in an almost perfectly hierarchical network, the power-law tail in firm size distribution disappears. The paper shows that aggregate demand shocks can affect the economy directly through the reduction in output for downstream firms and indirectly by shaping the firm size distribution.

13:50～14:25

論題
Topic

Freedom of Choice in Economic Games

報告者
Presenter

Ivan ROMIC（神戸大学計算社会科学研究センター）

概要
Abstract

Prisoner's dilemma, ultimatum game, and trust game are dyadic economics games used to study cooperation, fairness, and trust. Here, we present the evolution of these games from one-shot games between two players to repeated multiplayer games on various types of networks. We especially focus on the interactions between players and show how allowing players to freely choose with whom to interact increases cooperation, fairness, and trust. Finally, we present the latest theoretical and experimental advancement in games, and demonstrate their application in studies of pandemics, social polarization, and other key problems faced by modern societies.

14:25～14:35 休憩　Short Break

14:35～15:10

論題
Topic

Railway Passenger Traffic Volume and Google Maps Amenities: Investigating the Effects and Relationships Using Machine Learning

報告者
Presenter

Vera Paola Reyes SHODA（神戸大学計算社会科学研究センター）

概要
Abstract

Neighborhood amenities significantly impact people's traffic and attract the population to the area. This research aims to investigate the relationship between neighborhood amenities and the traffic volume of the 123 railway stations in Kobe City using data from Google Maps. Important amenity factors are identified using machine learning, such as the Extreme Gradient Boosting (XGB) algorithm. Results are expected to help public and private organizations develop and sustain urban amenities' diversity and availability.

15:10～15:45

論題
Topic

Positive Fuel Price Elasticities of Expressway Traffic Flows: Evidence from Japan

報告者
Presenter

Kashif AHMED（神戸大学経済経営研究所）

概要
Abstract

Literature suggests that higher fuel prices may encourage drivers to switch from local roads to expressways—implying a positive relationship between fuel prices and expressway traffic flows. This phenomenon is observable if the expressway significantly reduces travel distance or duration. The Hanshin Expressway, located in central Japan, provides an appropriate context for this study. We analyzed 16.57 million hourly traffic flows and found that fuel prices positively affected the traffic flows. We further found some significant differences in the fuel price elasticity of traffic flows during peak/off-peak hours across weekdays/weekends and its medium-run effect for five types of vehicles.

15:45～15:55 休憩　Short Break

15:55～16:30

論題
Topic

Voice Conversion Based on Deep Learning Models and Its Application to Practical Tasks

報告者
Presenter

陳　訓泉（神戸大学計算社会科学研究センター）

概要
Abstract

The voice is one of the most natural communication tools for human beings and it provides not only linguistic information but also paralinguistic information, which include speaker information and emotional information. Voice conversion (VC) is a technique for converting paralinguistic information, while preserving the linguistic information in the utterance. Earlier studies of VC are focused on modeling the mapping between source and target features with statistical methods. In recent years, deep learning has markedly improved the performance of VC systems through learning hierarchies of features optimized for the task at hand. In this presentation, I would like to present my research on VC based on deep learning models and its application to practical tasks (speaker conversion, emotion conversion, and assistive technology for articulation disorders).

16:30～17:05

論題
Topic

Applications of Text Mining and Agent-based Simulation Modeling of COVID-19 Pandemic

報告者
Presenter

Shady SALAMA（神戸大学計算社会科学研究センター）

概要
Abstract

In March 2020, the World Health Organization declared COVID-19 a pandemic that has since claimed the lives of millions of people worldwide, with serious economic and social consequences. Since then, many researchers from different fields have collaborated to address issues related to detection and transmission, medications, and non-pharmaceutical interventions to control the spread of the virus. The main focus of this presentation is to provide an overview of text mining techniques used to study data related to COVID-19. The covered methods include word frequency, document classification, sentiment analysis, topic modeling, and text summarization. Furthermore, this presentation briefly discusses Agent-Based Social Simulation (ABSS), which simulates the virus dynamics using a society of artificial agents (people), businesses, and government. ABSS is a very useful tool for policy-makers to make informed decisions (restrictions or policies) in a fast and cost-efficient manner.

17:05～17:10　閉会挨拶 / Closing Remarks

柴本　昌彦（神戸大学計算社会科学研究センター）