The purpose of this study is to identify the structural causes of the decline of the old town due to the development of new towns, and to seek policy alternatives for urban regeneration. For this purpose, the case of Gwangyang city was analyzed using Alfeld's Urban1 model. The analysis found that the most effective policy for maintaining the population in the old town was to promote demolition of aging businesses and to delay housing demolition. In general, promoting demolition of housing is considered an effective means of bringing in populations by increasing business locations and jobs. In the case of Gwangyang City, however, the demolition of old homes further raises housing prices in the face of the influx of population. This suggests that extending life of a houses through remodeling or repairing aging houses may be a more effective alternative than promoting house removal. This suggests that urban regeneration should be made in a manner appropriate to urban conditions depending on the circumstances of the city.

In this paper, we made causal maps for the policy of low birth rate and the job policy respectively, and found that there is no feedback loops in each policy. Given the long history of system dynamics study in the ignorance of feedback loops, this is not a surprising finding. A surprising finding in our study is that some clear feedback loops emerged when linking the policy of low birthrate and job policies. If you combine two policies that were handled separately, the invisible feedback loops reveals themselves When we have an integrated approach to the system, we can recognize the feedback loops inherent in the system, and have a more strategic approach to the system. This is the essential implication of our study.

Super-solo society is defined as the phenomenon in which a person living in solo becomes the majority of the population. The acceleration at which Korea's population is going solo is mainly a result of rapid growing trend of more young Koreans embracing a single lifestyle, the increase in bereavement due to the difference in life expectancy between men and women and the divorce of couples without children. Demographic changes such as aging and low fertility are becoming path structures of super-solo society. This study aims to identify the Causal feedback structure of its factors and effects based on the Systems Thinking. In particular, this study attempted to examine how fast the super-solo society progresses and what effect it will have in the future with the dominant causal structural analysis. Furthermore, this study explore the policy direction of how to respond to the super solo society.

The purpose of this study is to select a landscape planting scenario the facilitates recovery of carbon absorption by trees in reconstructed apartment complexes. The criteria for recovery were set as time and carbon absorption. The study site was a park planned site in Gaepo Apartment Complex 1, Gangnam-gu, Seoul. The research process consisted of investigating tree growth, investigating a causal loop diagram, and simulation of carbon absorption model using by Stella Architect. First, 177 trees of 17 species were planted on the site. Second, the causal loop diagram confirmed that the apartment landscaping space provides ecosystem services through carbon absorption and that carbon absorption could be changed by adjusting the ratio of transplantation to new plants. Currently, the site's carbon absorption is up to 10,970 (kg/yr). Analyses of four scenarios for transplanting and new planting rates show that scenario 2 was selected. Scenario 2 consists of 50% transplanted trees and 50% new trees. This takes 40 years to recover and the maximum possible absorption is 13,542(kg/yr). This study meaningful in that the planting standard was able to improve the function of the apartment landscape spaces as a carbon sink.

This study aims to understand the causal mechanisms of generating rebound effects from improved energy efficiency through system dynamics modeling. The modeling centers on the sector of automobile fuel-efficiency in the EU countries. Two different disciplines on rebound effects - economic theory and social practice theory - have developed explanations of why the phenomenon occurs by which a system dynamics model is developed.
Computer simulations allow seeing the long-term effect of the enhancement in fuel-efficiency, compared to the baseline trend, showing the size of the contribution to the energy-saving goals. The result of the simulations shows that the increase in fuel-efficiency does not ensure a reduction in energy consumption because of significant rebound effects. It likely causes even backfires leading to an increase in energy consumption. Policy experiments elucidate possible pathways to decouple between energy consumption and driving distance as well as to overcome backfires.

Korea launched the world's first commercial 5G services in April 2019, securing an advantageous position in preoccupying the new mobile market. But it was pursued somewhat radically for the first commercialization, systematic analysis of market demand base was overlooked. For that reason, this paper, in order to overcome the limitations of the solution of the analytical approach due to the high complexity of the real world, estimates the diffusion of 5G users through a multi-method technique that combines modeling based on systemic thinking with the behavior of individual agents. Based on these demand forecasts, it was tried to find a way to contribute to the establishment of strategic policies.
The simulations were conducted according to three rational scenarios based on potential subscribers. It was estimated that subscribers ranged from 39.95 million to 44.45 million at 81 months after the launching of 5G. This is lower than the actual 4G observations, which is attributed to the constraints of potential subscribers and coverage set in the simulation model. However, when the 5G potential saturation value is applied to the maximum of actual 4G subscriber, the simulation result was similar to the 4G increasing trend. Especially after 81 months, absolute percentage error rate was only 0.6% between the 4G real subscriber and the 5G predictive subscriber, which seems to support the validity of the model.

This article explores the dynamic characteristics of the basic new Keynesian model which is widely used in lots of the central banks in each country and educated for the advanced macroeconomics at the graduate level in economics. System dynamics can give help to reveal the dynamic states of the basic model. In this article, the particular assumptions or determination with regard to the basic model such as jump variables and determinacy or indeterminacy of the model, which make lots of students and nonspecialists difficult to understand the model, can be easily found by help of the computer-aided simulation of system dynamics and some further related studies.