• Journal of the Korea Society for Simulation
• /
• v.30 no.1
• /
• pp.103-112
• /
• 2021

In recent years, public bicycle systems are widely spread over the world according to the development of ICT technology. Since the public bicycle systems in large cities need to secure both publicity and convenience for citizens, analysis of various their issues from introduction to operation is required. In addition, it is also necessary to prepare for various scenarios for coexistence with the PM business, which is recently in the spotlight as a last mile means and normally managed privately. This paper introduces modeling and simulation for efficient operations of public bicycle systems. In particular, the proposed method was developed in a form that can be easily used in other cities by modeling the general structure and behavior of the public bicycle system, and it was developed to facilitate modification and expansion of the future model with a component-based model configuration. This paper provides a case study of the propose method, which is the public bicycle simulation in Sejong City. The simulation results were derived by applying the data from the public bicycle system of Sejong City, and they were verified with the associated real data of Sejong City. Using the verified model, it is expected that it can be used as a tool to design and analyze various services on the public bicycle systems, which were especially suitable for Sejong City.

• Journal of the Korea Convergence Society
• /
• v.12 no.8
• /
• pp.31-37
• /
• 2021

As the size of buildings increases due to urbanization due to the development of industry, the need to purify the air and maintain a comfortable indoor environment is also increasing. With the development of monitoring technology for refrigeration systems, it has become possible to manage the amount of electricity consumed in buildings. In particular, refrigeration systems account for about 40% of power consumption in commercial buildings. Therefore, in order to develop the refrigeration system failure diagnosis algorithm in this study, the purpose of this study was to understand the structure of the refrigeration system, collect and analyze data generated during the operation of the refrigeration system, and quickly detect and classify failure situations with various types and severity . In particular, in order to improve the classification accuracy of failure types that are difficult to classify, a three-step diagnosis and classification algorithm was developed and proposed. A model based on SVM and LGBM was presented as a classification model suitable for each stage after a number of experiments and hyper-parameter optimization process. In this study, the characteristics affecting failure were preserved as much as possible, and all failure types, including refrigerant-related failures, which had been difficult in previous studies, were derived with excellent results.

• The Journal of the Convergence on Culture Technology
• /
• v.7 no.3
• /
• pp.577-582
• /
• 2021

Recently, with the development of AR, VR, and smart device technologies, the demand for services based on non-face-to-face environments is also increasing in the fitness industry. The non-face-to-face online home training service has the advantage of not being limited by time and place compared to the existing offline service. However, there are disadvantages including the absence of exercise equipment, difficulty in measuring the amount of exercise and chekcing whether the user maintains an accurate exercise posture or not. In this study, we develop a standard exercise program that can compensate for these shortcomings and propose a new non-face-to-face home training application by using a deep learning-based body posture estimation image processing algorithm. This application allows the user to directly watch and follow the trainer of the standard exercise program video, correct the user's own posture, and perform an accurate exercise. Furthermore, if the results of this study are customized according to their purpose, it will be possible to apply them to performances, films, club activities, and conferences

• Knowledge Management Research
• /
• v.22 no.4
• /
• pp.135-155
• /
• 2021

With the emergence of various types of social media and the diversification of their roles, it has become essential for marketers to understand how different types of social media influence consumers' purchase decisions differently and derive more detailed strategies by social media types. This study classifies social media into two types-expression-focused social media and relationship-focused social media-and investigates the relationship between consumer purchases and social media mentions by type. Using the Seoul bike-sharing data and time-series data for social media mentions, we apply the VAR model with Exogenous Variables (VARX). We find that the increase of product mentions in expression-focused social media positively affects both the number of new customers (customer acquisition) and the number of shared bike rentals, while that in relationship-focused social media negatively affects the number of new customers only. In addition, as new customers increase, the product mentions in both types of social media increase. On the other hand, the number of bike rentals has no significant effect in increasing social media mentions regardless of type. This study contributes to the social media and sharing economy literature and provides managerial implications for establishing sophisticated social media marketing in bike-sharing businesses.

• Journal of Digital Convergence
• /
• v.20 no.4
• /
• pp.353-366
• /
• 2022

The study sets out to examine the relationship between the effects of government support, network capability, and knowledge sharing on the effects of innovative behavior on innovation performance. As digital-based networks and knowledge sharing activities are rapidly becoming common in the era of the spread of Covid-19, 357 questionnaires were analyzed for incumbent employees and the research hypotheses are verified using SPSS 24 and smart PLS 3 to prove the relationships between variables. As a result of the study, it is found that innovation performance increased when government support, network capability, and knowledge sharing increased. Innovative behavior is found to significantly mediate the relationship between network capability, knowledge sharing, and innovation performance, and government support was found to have a significant effect on network capabiltiy. Therefore, in order to induce innovative actions that are important in creating innovative results, various programs to enhance the network capabilities of entrepreneurs and promote knowledge sharing should be required as government support policies. This will serve as a driving force for entrepreneurs to voluntarily develop and implement ideas more flexibly and freely, thereby enhancing competitiveness through innovative growth of companies and industries. In other words, this study verified the effectiveness of government support in the network capability to help create innovative results by inducing innovative behavior along with knowledge sharing activities, and comprehensively demonstrated the relationship between factors in the overall structure.

• Journal of Environmental Health Sciences
• /
• v.48 no.2
• /
• pp.66-74
• /
• 2022

Background: The health effects of particulate matter (PM_2.5) bonded with various harmful chemicals differ based on their composition, so investigating and managing their concentrations and composition is vital for long-term management. As industrial complexes emit considerable quantities of pollutants, higher PM_2.5 concentrations and chemical component effects are expected than in other places. Objectives: We investigated the concentration distribution ratios of PM_2.5 chemical components to provide basic data to inform future major emissions control and PM_2.5 reduction measures in industrial complexes. Methods: We monitored five sites near the Ansan and Siheung industrial complexes from August 2020 to July 2021. Samples were collected and analyzed twice per week in spring/winter and once per week in summer/autumn according to the National Institute of Environmental Research in the Ministry of Environments' Air Pollution Monitoring Network Installation and Operation Guidelines. We investigated and compared composition ratios of 29 ions, carbon, and elemental components in PM_2.5. Results: The analysis of PM_2.5 components at the five sites revealed that ion components accounted for the greatest total mass at approximately 50% while carbon components and elemental components contributed 23~28% and 8~10%, respectively. Among the ionic components, NO₃^- occupies the greatest proportion. OC occupies the greatest proportion of the carbon components and sulphur occupies the greatest proportion of elemental components. Conclusions: This study investigated the concentration distribution ratios of PM_2.5 chemical components in industrial complexes. We believe these results provide basic chemical component concentration ratio data for establishing future air management policies and plans for the Ansan and Siheung industrial complexes.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.2
• /
• pp.47-52
• /
• 2022

The purpose of this study is to identify the risk level of Chinese commercial banks' loan assets and to analyze what factors affect the stability of Chinese commercial banks. In addition, Chinese commercial banks are classified based on the asset size of 200 billion yuan, and the difference in stability according to size is investigated. The analysis results are as follows. First, it was estimated that as the proportion of household and corporate loans of commercial banks in China increased, the stability of banks decreased. Although the Chinese financial authorities are currently restricting the conservative management of loan assets, it will be necessary to preemptively manage risk on loan assets by setting an appropriate standard for loan-to-deposit ratio in the future. Second, as a result of analyzing the stability of large banks based on 200 billion yuan of bank assets, it was estimated that the stability of large banks was lower. As large banks are likely to conduct aggressive loan asset management, continuous management of non-performing assets is required in the future. This study will serve as a measure for improving the stability of commercial banks in China by estimating the effect of loan asset management of Chinese commercial banks on financial stability. In particular, by examining the stability of large banks, a strategy for sustainable development of the financial industry is required by diagnosing the weaknesses of large banks.

• Resources Recycling
• /
• v.31 no.4
• /
• pp.3-11
• /
• 2022

Owing to the increasing demand for electric vehicles (EVs), appropriate management of their waste batteries is required urgently for scrapped vehicles or for addressing battery aging. With respect to technological developments, data-driven diagnosis of waste EV batteries and management technologies have drawn increasing attention. Moreover, robot-based automatic dismantling technologies, which are seemingly interesting, require industrial verifications and linkages with future battery-related database systems. Among these, it is critical to develop and disseminate various advanced battery diagnosis and assessment techniques to improve the efficiency and safety/environment of the recirculation of waste batteries. Incorporation of lithium-related chemical substances in the public pollutant release and transfer register (PRTR) database as well as in-depth risk assessment of gas emissions in waste EV battery combustion and their relevant fire safety are some of the necessary steps. Further research and development thus are needed for optimizing the lifecycle management of waste batteries from various aspects related to data-based diagnosis/classification/disassembly processes as well as reuse/recycling and final disposal. The idea here is that the data should contribute to clean design and manufacturing to reduce the environmental burden and facilitate reuse/recycling in future production of EV batteries. Such optimization should also consider the future technological and market trends.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.31 no.6
• /
• pp.282-286
• /
• 2021

Penetration depth and compressive residual stress of laser-carburized TiZrN coating by thickness of carbon paste were investigated in terms of carbon potential. The carbon paste was covered with a thickness of 1.1 mm using screen printing, and applied to a thickness of 0.4 mm using spin coating, and laser carburization was performed under the same conditions. As the thickness of carbon paste increased, the diffraction pattern of the laser-carburized TiZrN coating shifted to a lower angle, indicating solid solution strengthening and lattice distortion. For microstructure analysis using TEM, the defects and carbon concentration of the laser-carburized TiZrN coating increased as the carbon paste was thicker. It indicated that the variation of the carbon potential corresponds to the change in the paste thickness. In XPS depth profile analysis, high concentration of carbon and formation of carbide were observed in laser-carburized TiZrN coating with thick carbon paste. It revealed that the carbon concentration on the surface and carbon potential were changed by the thickness control of carbon paste. The compressive residual stress increased from 3.67 GPa to 4.58 GPa by the variation of carbon concentration.

• Journal of Life Science
• /
• v.32 no.10
• /
• pp.778-783
• /
• 2022

This study isolated a new agarase-producing bacterium and characterized its agarase. A new agar-degrading strain was isolated from the seashore of Namhae in Gyeongnam province, Korea, and was purely cultured using the Marine Agar 2216 media. The isolated bacterium was identified as Simiduia sp. SH-2 after 16S rRNA gene sequencing. The crude agarase was obtained from the culture medium of the Simiduia sp. SH-2 strain, and the agar-degrading activity was measured. The highest level of activity of the Simiduia sp. SH-2-derived agar-degrading enzyme was 625 U/l. Agar degradation activity was most significant at 40℃ and pH 7.0. Compared to the activity at 40℃, the relative activity was 31% at 20℃ and 71% at 30℃. Compared to the activity at pH 7.0, the relative activity was 94% and 89% at pH 6.0 and pH 8.0, respectively. Residual activity was greater than 96% after exposure to 20℃ and 30℃ for 2 hr and more than 49% after exposure to 40℃ for 2 hr. Simiduia sp. SH-2 was identified as a strain producing β-agarase that creates neoagarooligosaccharides, such as neoagarotetraose and neoagarohexaose. Therefore, the Simiduia sp. SH-2 strain and its β-agarase are expected to be useful functional material producers in the food, cosmetic, and pharmaceutical industries.