• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.4
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• pp.15-22
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• 2020

The landfill gas produced in landfill is generally made up of methane(CH4) and carbon dioxide(CO2) of more than 90%, with the remainder made up of hydrogen sulfide(H2S). However, separate pre-treatment facilities are essential as hydrogen sulfide contained in landfill gas is combined with oxygen during the combustion process to generate sulfur oxides and acid rain combined with moisture in the atmosphere. Various desulfurization technologies have been used in Korea to desulfurize landfill gas. Although general desulfurization processes apply various physical and chemical methods, such as treatment of sediment generation according to the CaCO3 generation reaction and treatment through adsorbent, there is a problem of secondary wastes such as wastewater. As a way to solve this problem, a biological treatment process is used to generate and treat it with sludge-type sulfide (S°) using a biological treatment process.In this study, as a basic study of technology for utilizing the biological treatment by-products of hydrogen sulfide in landfill gas, an experiment was conducted to use the by-product as a mixture of concrete. According to the analysis of the mixture concrete strength of sulfur products, the mixture of sulfur by-products affects the strength of concrete and shows the highest strength value when mixing 10%.

• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.688-696
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• 2020

Petroleum coke (petcoke) is widely used, next to coal, as a gasification feedstock. In gasification processes, the viscosity of the ash and the formation of crystalline phases must be understood to ensure the continuous removal of slag. This study investigates the effect of CaO and V2O3 on petcoke slag viscosity. The viscosity of the molten slag was measured in the temperature range of 1100~1600 ℃ while varying the concentration of each component. The crystalline phases formed in a cooled slag were examined. The most slag samples tested in this study exhibited crystalline slag behavior. The increased CaO concentration resulted in a lower viscosity and a lower Tcv. The viscosity behavior changed from the glassy to crystalline slag and also showed a higher Tcv as the concentration of V2O3 increases. Most slag samples showed different crystalline phases from top to bottom. Anorthites and Ca-V phases were observed in the top and middle section, while the bottom section mainly showed V2O3 and anorthite. The vanadium in the ash forms Ca-V and V-Fe phases and also remains in molten slag. A low melting Ca-V phase can contribute to lowering the viscosity.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.51-57
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• 2022

This paper investigated catalytic and adsorption equations among the technologies for removing hazardous substances generated in the semiconductor process. As the semiconductor industry develops, harmful substances used and discharged in the semiconductor process are also increasing. Hazardous substances adversely affect the global environment in terms of atmospheric and water quality. As regulations on the emission of harmful substances are strengthened in the 21st century, it is expected that there will be limitations in industrial development in the future. Therefore, technology for removing harmful substances generated in semiconductor processes is essential. In this paper, the goal is to remove PFCs, which are harmful substances, through adsorption technology and catalyst technology. Descriptions from the semiconductor process to the technology in which harmful substances generated are removed were summarized.

• Applied Chemistry for Engineering
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• v.32 no.4
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• pp.409-416
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• 2021

Dimensionally stable electrodes are one of the important components in electrochemical water treatment processes. In the manufacturing of the dimensionally stable electrodes, the type of metal catalyst coated on the surface of the metal substrate, the coating and sintering methods substantially influence their performance and durability. In this study, using Ir-Ru-Ta ternary metal coating, various electrodes were prepared depending on the coating method under the same pre-treatment and sintering conditions, and its performance and durability were studied. As a coating method, brush and spray coating were used. As a result, the reduction in the amount of catalyst ink was achieved because more amount of metal could be coated for the electrode using spraying with the same amount of catalyst ink. In addition, the spray_2.0_3.0 electrode prepared by a specific spray coating method shows the phenomenon of cracking and the uniform coating of the ternary metal on the surface of the coating layer, and results in a high electrochemically active specific surface area, and the decomposition performance of 4-chlorophenol was superior to the other electrodes. However, it was found that there was no significant difference in durability depending on the coating method.

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.384-389
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• 2011

We made suspension of fumed silica in polyethylene glycol (PEG), studied rheological behavior as functions of contents of silica, dispersion condition, PEG molecular weight, temperature and contents of humidity. Rheological behavior of suspension was determined critical shear rate and rise of viscosity using rheometer AR2000. Suspension were PEGs of molecular weight 200, 400, and 600. Fumed silica suspensions of which silica contents are 5, 7, 9, 13, and 18% were prepared by normal mixing, homogenization and bead milling process. We observed their rheological behaviors at 10, 20, 30, and $40^{\circ}C$. As the PEG molecular weight and contents of silica increase, the critical shear rate was lowered. As the temperature increased, the critical shear rate was increased. Humidity contents of dispersion don't influence on the critical shear rate, but dispersion processes greatly affect the critical shear rate. The critical shear rate of suspensions prepared by the mixing process was the lowest, and that of suspensions prepared by the bead milling process was the highest. The rise in the shear viscosity of suspensions prepared by the mixing process is higher than that of suspensions prepared by the bead milling process. This was dependent on the dispersion condition of silica particle by dispersion process.

• Journal of Internet of Things and Convergence
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• v.7 no.2
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• pp.21-29
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• 2021

In this study, it is necessary to supplement the Korean language curriculum in order for international students to adapt and settle in Korea in an era where education is being transformed into future education due to the 4th industry. In the KFL (Korean as a Foreign Language) situation encountered by international students, they suffer from difficulties in university mathematics due to communication problems due to lack of language ability, which is one of the stress factors for cultural adaptation in the Korean language education program. To solve this problem, we analyzed ESL programs in English-speaking countries and KSL programs in Korea to set educational goals, curriculum, and educational methods to achieve goals for international students, and to establish curriculum and learning processes. Therefore, the Korean language education program (KSL program) for foreign students in the Korean language curriculum should also be supplemented by accepting the advantages of setting accurate goals for the ESL program and linking it with university graduation in the curriculum of English-speaking countries. In addition, for international students to learn Korean, an integrated Korean language education course and management system using IT suitable for the 4th industrial age is needed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.4
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• pp.387-393
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• 2020

Objective: This study aimed to investigate the differences in temporary threshold shift (TTS) and recovery patterns according to different types of sound and volume. Methods: TTS and recovery patterns were assessed for eight students after 30-minute exposure to both 70.0 dB and 90.0 dB of factory noise (noise) as well as music. TTS was measured before exposure and two minutes post exposure, and recovery patterns were evaluated every 10 minutes for one hour. The subjects performed activities of daily life and sleeping times as usual but taking drugs or drinking alcohol were prohibited. The experiment was repeated three times with an interval of at least 16 hours. ANOVA and T-test were carried out using SPSS 19.0 for Windows. Results: The hearing threshold of all subjects before exposure was less than 30 dB at all frequencies. Mean TTSs of 70 dB noise and 90 dB noise exposure were 0.14 and 4.48 dB (p<0.001). Meanwhile, the difference in music was insignificant (-0.63 dB and 0.55 dB, p=0.063). A significance in the difference was also found between the mean TTS of music and noise exposure, more obviously at 90.0 dB (p<0.001) than at 70 dB (p=0.232). The TTS differences were found frequency-wise in terms of sound type. Mean TTS by frequency was higher at 4,000 and 6,000 Hz than at other frequencies, and higher in noise than music at the same sound pressure. The TTS difference in each frequency between both sound types was significant at 90 dB (p<0.001). Subjects mostly recovered from TTS in one hour after exposure, but not with 90 dB-noise exposure. Conclusion: TTS and recovery patterns were different depending on the sound type. When exposed to factory noise, TTS was greater and recovery time was longer compared to music at the same sound pressure. These results suggested that the difference in cognitive processes and psychological factors according to the type of sound causes a change in TTS and recovery.

• Knowledge Management Research
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• v.22 no.4
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• pp.283-301
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• 2021

RPA (Robotic Process Automation) technology has recently been spotlighted to preemptively respond to the 4th industrial revolution without spending a lot of time and money to improve various existing business and IT processes. In this study, variables affecting intention to use RPA technology were representatively identified into three positive factors and three negative factors, and the causal relationship between the effects of these variables on actual RPA acceptance intention was examined. After conducting an email survey for general office workers, structural equation analysis (SEM) was performed using SPSS 27.0 and SmartPLS 3.3.5. The second order factor of a positive perception consisting of security, accuracy, and efficiency, and the second order factor of a negative perception consisting of job security, execution error, and fear of introduction failure. The positive perception affected the intention to use RPA through perceived usefulness and perceived ease. It was confirmed that the negative perception has a mediating effect on the intention to use RPA through acceptance conflict. In addition, it was confirmed that the presence or absence of experience in using RPA interacts with perceived ease and has a moderating effect on intention to use RPA. It can be said that there is practical and theoretical implications from the point of view of knowledge management in that it allows companies to recognize and respond to which factors are important from the point of view of companies that want to use RPA.

• International Journal of Computer Science & Network Security
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• v.22 no.1
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• pp.331-339
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• 2022

The global process of transition from industrial to information society, as well as socio-economic changes taking place in Ukraine, require significant changes in many areas of state activity. It is especially connected with the reforms in the sphere of education. Today, national programs provide for the development of education on the basis of new progressive concepts, the introduction of the educational process of new pedagogical technologies and scientific achievements, the creation of a new system of information education, entrance of Ukaine into the transcontinental computer information system. Information technologies are qualitatively changing the key resources of development: this is no longer a space with fixed production, but primarily mobile finance and intelligence. They have a direct impact on the formation of personal growth, professional content and self-organization, emotional and psychological maturity and consciousness, and so on. One of the main factors in ensuring the stability and social education of the country's citizens is the culture of security, the formation and development of which is an urgent problem today. Comprehensive and systematic development of security culture will significantly increase the readiness of the population, the level of environmental, labor and patriotic education, reduce human losses, material damage from emergencies. Ecological education can be carried out more successfully only gradually and in accordance with the socio-psychological periods of one's development: kindergarten - school - college - university. The creation of such a system of environmental education should be enshrined as the basis of state environmental policy as a constitutional norm with the usage of information technology. Graduates of universities, who are the future of our country, after mastering the skills of basic environmental education must have a high level of environmental culture, which is, in turn, part of general human culture, and investigate environmental issues from the standpoint of their profession. It is known that with the help of environmental education the collective intelligence of society is formed, which can predict human activities and processes occurring in nature, and in some way to help with the elimination of crises. It is through environmental education that another system of human values is being formed, which places great emphasis on intangible wealth and solidarity, and great responsibility of humanity for the ecological state of the native country; provides a higher standard of living as a result of sustainable development, through the introduction of information technology in this system. To improve the quality of life, we need better knowledge, which must be implemented through information technology at the international level.

• The Journal of the Korea Contents Association
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• v.22 no.7
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• pp.55-62
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• 2022

The perovskite solar cell is an active part of research in renewable energy fields such as solar energy, wind, hydroelectric power, marine energy, bioenergy, and hydrogen energy to replace fossil fuels such as oil, coal, and natural gas, which will gradually disappear as power demand increases due to the increase in use of the Internet of Things and Virtual environments due to the 4th industrial revolution. The perovskite solar cell is a solar cell device using an organic-inorganic hybrid material having a perovskite structure, and has advantages of replacing existing silicon solar cells with high efficiency, low cost solutions, and low temperature processes. In order to optimize the light absorption layer thin film predicted by the existing empirical method, reliability must be verified through device characteristics evaluation. However, since it costs a lot to evaluate the characteristics of the light-absorbing layer thin film device, the number of tests is limited. In order to solve this problem, the development and applicability of a clear and valid model using machine learning or artificial intelligence model as an auxiliary means for optimizing the light absorption layer thin film are considered infinite. In this study, to estimate the light absorption layer thin-film optimization of perovskite solar cells, the regression models of the support vector machine's linear kernel, R.B.F kernel, polynomial kernel, and sigmoid kernel were compared to verify the accuracy difference for each kernel function.