Shigeaki Ogibayashi

Multi-Agent Simulation of Fund Circulation in an Artificial Economic System Involving Self-Adjusted Mechanism of Price, Production and Investment

An artificial economic system composed of producers, consumers and a bank was modeled and macroscopic behavior of the system was simulated based on microscopic rules of acts of each agent, where it was assumed that the consumers buy products within the limit of their disposable income, selecting the cheapest product in the market, and producers hire consumers, pay them salary, feed products to the market adjusting both the amount and price of products based on both their amount of goods in stock and total sales during some periods and sometimes invest in equipment, borrowing money from the bank. As a result, it was revealed that the calculated macroscopic behavior of the artificial economic system shows in good agreement with that of a real system in that the market price tends to an equilibrium price depending on the supply and demand of products in the market, two types of producers, winners and losers, arise depending on the production cost with some of the losers ending up going bankrupt, and a business cycle emerges through the fund circulation among agents where total deposit and loaned money in the bank showed cyclic up and down movement in time.

Influence of Government Expenditure Policies and Tax Rate on GDP in an Agent-Based Artificial Economic System

We developed an agent-based model of an artificial economic system that includes government, and we analyzed the influences of public policies on GDP and the related emergent behavior of macroeconomic phenomena. It was revealed that GDP increases with an increase in the ratio of efficient expenditure policy, such as that pertaining to market purchasing. The average price increases (decreases) as GDP increases (decreases), and the influence of tax rate on GDP, depend on the nature of public spending. Most estimation results are found to be quite consistent with real data if it is assumed that public spending includes an inefficiency exceeding 10%.

Influence of the Corporation Tax Rate on GDP in an Agent-Based Artificial Economic System

An agent-based model of an artificial economic system, including the government, was developed on the basis of the authors’ previous model. This model was used to analyze the factors influencing the relationship between GDP and the corporation tax rate and its mechanism. The findings show that executive compensation and the use of producers’ own cash for investment are both indispensable factors for reproducing the negative correlation between GDP and the corporation tax rate, because these actions help redistribute the firm’s surplus money to the market. Inefficiency in government expenditure is another indispensable condition. The calculated average multipliers for the reduction of both income tax and corporation tax are in good agreement with real data based on the macroeconometric model.

Theoretical analysis of the suppression of solidification shrinkage flow in continuously cast steel blooms

Abstract Theoretical estimation of the reduction of solidifying strand in the continuous casting of steels is very important for precise control of the centre segregation for various steels. In this study, the squeezing phenomenon in continuously cast steel blooms has been theoretically analysed by taking enrichment of solute elements into consideration to elucidate an optimum condition for suppressing the solidification shrinkage flow of high carbon steels. It has been found that the effect of carbon content on the squeezing conditions of the mushy zone is relatively small, although the solidification profile becomes longer with the increase in carbon content.