Journal on Policy and Complex Systems
literature ( Marks , 2007 ). However , it should also be noted that the freedom of input conditions decreases if they are expressed by the system structure of the model ( i . e ., model structure ) ( Ogibayashi & Takashima , 2014 ). Here , the model structure is defined as the set of the types of agents , their behavioral rules , and the relevant attributes variables . Consequently , it would be considered possible to specify the necessary conditions in the model structure to reproduce the specific macro behavior . This idea is consistent with the argument of Ormerod and Rosewell ( 2009 ), who pointed out that the current method used to build ABMs is a process of discovering the behavioral rules for agents that appear to be consistent with the phenomena we observe .
In this context , we believe that , although the model should be as simple as possible ( based on the KISS Principle ; Terano , 2008 ), it is also important to consider all of the factors required to reproduce the desired phenomena . That is , the model structure should be the same as , or similar to , the real system for the characteristics to emerge as they do in the real world . The factors essential for reproducing the desired characteristics of the system can be discovered by running a series of computer experiments in which only one constituent element of the model is changed at a time ( Ogibayashi & Takashima , 2014 ).
Although many ABM research studies have focused on macroeconomic aspects , these studies have not fully clarified the structural factors necessary for their reproduction .
Motivated by this deficiency , the authors have constructed a simple , artificial economic model , consisting of consumers , three types of producers , a bank , and a government ( some of which were reported in previous studies : e . g ., Ogibayashi & Takashima , 2010 & 2014 ; Takashima , Kato , & Ogibayashi , 2014 ).
In the present study , some additional simulations are conducted to clarify the model structure necessary for reproducing business cycles and an increase in GDP caused by a tax reduction ( which we take as examples of basic macro behaviors in a goods market ). A series of simulation experiments are systematically conducted , changing the input conditions one by one , where the simulation program is constructed using C ++. The study focuses on finding the model structure necessary to reproduce the above-mentioned macroeconomic phenomena .
2 . The Model
2.1 Outline of the Model
The agent-based model of the artificial economic system in the present study includes consumers , producers , a bank , and a government as autonomous decision-making agents . The type of agents and their behavioral rules are shown in Table 1 , which are changed depending on the experimental levels . Consumers are divided into three types of agents : workers as the base type , executives who are included or not in the model in the analysis of the effect of corporate tax reduction and public workers when the
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