• International Journal of Computer Science & Network Security
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• v.21 no.11
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• pp.345-353
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• 2021

Cloud computing represent a new era of computing that's forms through the combination of service-oriented architecture (SOA), Internet and grid computing with virtualization technology. Virtualization is a concept through which every cloud is enable to provide on-demand services to the users. Most IT service provider adopt cloud based services for their users to meet the high demand of computation, as it is most flexible, reliable and scalable technology. Energy based performance tradeoff become the main challenge in cloud computing, as its acceptance and popularity increases day by day. Cloud data centers required a huge amount of power supply to the virtualization of servers for maintain on- demand high computing. High power demand increase the energy cost of service providers as well as it also harm the environment through the emission of CO₂. An optimization of cloud computing based on energy-performance tradeoff is required to obtain the balance between energy saving and QoS (quality of services) policies of cloud. A study about power usage of resources in cloud data centers based on workload assign to them, says that an idle server consume near about 50% of its peak utilization power [1]. Therefore, more number of underutilized servers in any cloud data center is responsible to reduce the energy performance tradeoff. To handle this issue, a lots of research proposed as energy efficient algorithms for minimize the consumption of energy and also maintain the SLA (service level agreement) at a satisfactory level. VM (virtual machine) consolidation is one such technique that ensured about the balance of energy based SLA. In the scope of this paper, we explore reinforcement with fuzzy logic (RFL) for VM consolidation to achieve energy based SLA. In this proposed RFL based active VM consolidation, the primary objective is to manage physical server (PS) nodes in order to avoid over-utilized and under-utilized, and to optimize the placement of VMs. A dynamic threshold (based on RFL) is proposed for over-utilized PS detection. For over-utilized PS, a VM selection policy based on fuzzy logic is proposed, which selects VM for migration to maintain the balance of SLA. Additionally, it incorporate VM placement policy through categorization of non-overutilized servers as- balanced, under-utilized and critical. CloudSim toolkit is used to simulate the proposed work on real-world work load traces of CoMon Project define by PlanetLab. Simulation results shows that the proposed policies is most energy efficient compared to others in terms of reduction in both electricity usage and SLA violation.

• Journal of Environmental Health Sciences
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• v.49 no.2
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• pp.108-117
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• 2023

Background: When particles are absorbed into the human body, they penetrate deep into the lungs and interact with the tissues of the body. Heavy metals in PM_2.5 can cause various diseases. The main source of PM_2.5 emissions in South Korea's atmosphere has been surveyed to be places of business. Objectives: The concentration of heavy metals in PM_2.5 near the Ulsan Industrial Complex was measured and a health risk assessment was performed for residents near the industrial complex for exposure to heavy metals in PM_2.5. Methods: Concentrations of heavy metals in PM_2.5 were measured at four measurement sites (Ulsan, Mipo, Onsan, Maegok) near the industrial complexes. Heavy metals were analyzed according to the Air Pollution Monitoring Network Installation and Operation Guidelines presented by the National Institute of Environmental Research. Among them, only five substances (Mn, Ni, As, Cd, Cr⁶⁺) were targeted. The risk assessment was conducted on inhalation exposure for five age groups, and the excess cancer risk and hazard quotient were calculated. Results: In the risk assessment of exposure to heavy metals in PM_2.5, As, Cd, and Cr⁶⁺ exceeded the risk tolerance standard of 10^-6 for carcinogenic hazards. The highest hazard levels were observed in Onsan and Mipo industrial complexes. In the case of non-carcinogenic hazards, Mn was identified as exceeding the hazard tolerance of 1, and it showed the highest hazard in the Ulsan Industrial Complex. Conclusions: This study presented a detailed health risk from exposure to heavy metals in PM_2.5 by industrial complexes located in Ulsan among five age groups. It is expected to be utilized as the basis for preparing damage control and industrial emission reduction measures against PM_2.5 exposure at the Ulsan Industrial Complex.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.3
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• pp.239-251
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• 2023

The aim of this study is to evaluate the effect of noise-filtering earplugs on the hearing ability of dentists wearing them during noise-induced dental procedures. Pure tone audiometry and distortion product otoacoustic emission (DPOAE) tests were conducted at the initial visit and 1 year later to evaluate the hearing ability of the participants. As a result of the study, the pure tone average of the group wearing earplugs decreased significantly compared to the group not wearing earplugs, indicating an improvement in hearing. However, the signal-to-noise ratio of the DPOAE tests did not show a significant difference. These findings suggest that noise-filtering earplugs may have some effectiveness in preventing hearing loss. However, since the 1-year observation period may not be adequate to identify changes in hearing, a follow-up study with an extended follow-up period is necessary.

• Korean Journal of Construction Engineering and Management
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• v.24 no.5
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• pp.12-21
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• 2023

Green remodeling proposed in the Korean New Deal is a project to build or remodel eco-friendly and energy-efficient buildings using renewable energy facilities and high-performance insulation for public buildings. The government intends to achieve the carbon emission reduction target by conducting green remodeling. Major overseas cities that conduct green remodeling are actively promoting technology support and promotion along with energy performance evaluation according to building characteristics, subsidies for private revitalization, and tax benefits. With this background, the analysis of the current status and problems of the green remodeling project was performed and the Activation factors of Green Remodeling were derived from survey results. This study suggested strategic measures such as a participation of civil society, promotion, and priority selection of administration and policy measures such as a leading role of the public sector, expanding support for the socially underprivileged, and financial support and tax benefits. And this study results are expected to be utilized as basic data to promote the green remodeling project.

• Journal of Industrial Convergence
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• v.21 no.7
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• pp.19-27
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• 2023

As the secondary battery market expands, the process of producing laterite ore using the rotary kiln and electric furnace method is expanding worldwide. As ESG management expands, the management of air pollutants such as nitrogen oxides in exhaust gases is strengthened. The rotary kiln, one of the main facilities of the pyrometallurgy process, is a facility for drying and preliminary reduction of ore, and it generate nitrogen oxides, thus prediction of nitrogen oxide is important. In this study, LSTM for regression prediction and LightGBM for classification prediction were used to predict and then model optimization was performed using AutoML. When applying LSTM, the predicted value after 5 minutes was 0.86, MAE 5.13ppm, and after 40 minutes, the predicted value was 0.38 and MAE 10.84ppm. As a result of applying LightGBM for classification prediction, the test accuracy rose from 0.75 after 5 minutes to 0.61 after 40 minutes, to a level that can be used for actual operation, and as a result of model optimization through AutoML, the accuracy of the prediction after 5 minutes improved from 0.75 to 0.80 and from 0.61 to 0.70. Through this study, nitrogen oxide prediction values can be applied to actual operations to contribute to compliance with air pollutant emission regulations and ESG management.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.158-159
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• 2022

Due to the climate crisis, various environmental regulations including greenhouse gas reduction are in effect. This is not limited to any specific industry sector, but is affecting the entire industry worldwide. For this reason, the IMO and governments of each country are announcing strategies and policies related to the shipbuilding and shipping industries. The current regulations can be partially resolved through additional facilities such as scrubbers while using existing fossil fuels, but ultimately, the emission of greenhouse gases such as CO2 from the exhaust gases generated by ships must be restricted through energy conversion. To this end, it is necessary to develop fuels that can replace traditional fuels such as oil and natural gas. Among them, hydrogen is attracting attention as a clean energy that does not emit pollutants when used as a fuel. However, hydrogen has a wide explosive range and a fast dispersion speed, so research on this is necessary. Therefore, in this paper, when hydrogen leakage occurs in the fuel preparation room of a hydrogen-powered ship, the trend was analyzed and the ventilation characteristics were investigated.

• Journal of Korea Port Economic Association
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• v.39 no.3
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• pp.107-122
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• 2023

This study aims to analyze the effect of reducing air pollutant emissions of the ship fuel oil sulfur content regulation policy, which has been gradually introduced for three years. In addition, the emission reduction effect of VSR and AMP was also analyzed. The analysis was conducted on NOx, CO, VOC, SOx, TSP, PM10, and PM2.5, which are provided by EEA, and the spatial scope of the analysis was conducted on Incheon Port, which is located in the metropolitan area of Korea and has a large ripple effect on air pollution. Three scenarios were constructed for analysis. Scenario 1: If there is no policy, Scenario 2: If only fuel oil sulfur content regulation was implemented, Scenario 3: The analysis was conducted by reflecting fuel oil sulfur content regulation, VSR, and AMP. As a result of the analysis, in the case of scenario 1, 4,801 tons, 4,932 tons, and 5,144 tons of air pollutants were emitted during the three-year period. In Scenario 2, 4,219 tons, 4,152 tons, and 3,989 tons were discharged, and in Scenario 3, 4,198 tons, 4,138 tons, and 3,973 tons were discharged. The findings of this study are anticipated to be applied as fundamental research in port air environment management and Incheon Metropolitan City air management.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.522-528
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• 2023

In this work, adhesive tapes were prepared for the dicing process in semiconductor manufacturing. Compounds with different numbers of photoreactive groups (f = 1 to 3) were synthesized and incorporated into acrylic copolymers to formulate UV-curable acrylic adhesives. Structural confirmation of the synthesized photoreactive compounds (f = 2 or 3) was performed using nuclear magnetic resonance (NMR) spectroscopy. The introduction of the photoreactive compounds into the acrylic adhesive was accomplished by urethane reactions, and the successful synthesis of the UV-curable acrylic adhesive was verified by Fourier transform infrared (FT-IR) measurements. To evaluate the performance of the adhesive, the peel strength was evaluated before and after UV irradiation using a silicon wafer as a substrate. The adhesive exhibited high peel strength (~2000 gf/25 mm) before UV exposure, which was significantly reduced (~5 gf/25 mm) after UV exposure. Interestingly, the adhesive containing multifunctional photoreactive compounds showed the most significant reduction in peel strength. In addition, surface residue measurements by field emission scanning electron microscopy (FE-SEM) showed minimal surface residue (~0.2%) after UV exposure. Overall, these results contribute to the understanding of the behavior of UV-curable acrylic adhesives and pave the way for potential applications in semiconductor manufacturing processes.

• Journal of Korea Port Economic Association
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• v.39 no.2
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• pp.41-57
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• 2023

The drybulk shipping market has high freight rate volatility in the chartering market and various and complex factors affecting the market. In the unstable economic situation caused by the COVID-19 pandemic in 2020, the BDI plunged due to a decrease in trade volume, but turned from the end of 2020 and maintained a booming period until the end of 2022. The main reason for the market change is the decrease in the available fleet that can actually be operated for cargo transport due to port congestion by the COVID-19 pandemic, regardless of the fleet and trade volume volatility that have affected the drybulk shipping market in the past. A decrease in the actual usable fleet due to vessel waiting at port by congestion led to freight increase, and the freight increase in charting market led to an increase in second-hand ship and new-building ship price in long-term equilibrium relationship. In the past, the drybulk shipping market was determined by the volatility of fleet and trade volume. but, in the future, available fleet volume volatility by pandemics, environmental regulations and climate will be the important factors affecting BDI. To response to the IMO carbon emission reduction in 2023, it is expected that ship speed will be slowed down and more ships are expected to be needed to transport the same trade volume. This slowdown is expected to have an impact on drybulk shipping market, such as a increase in freight and second-hand ship and new-building ship price due to a decrease in available fleet volume.

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.93-105
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• 2024

Purpose: This study aims to quantitatively determine the impact on nearby risidents by selecting the amount of chemicals emitted from the workplace among the substances subject to the chemical emission plan and predicting the concentration with the atmospheric diffusion program. Method: The selection of research materials considered half-life, toxicity, and the presence or absence of available monitoring station data. The areas discharged from the materials to be studied were selected as the areas to be studied, and four areas with floating populations were selected to evaluate health risks. Result: AERMOD was executed after conducting terrain and meteorological processing to obtain predicted concentrations. The health hazard assessment results indicated that only dichloromethane exceeded the threshold for children, while tetrachloroethylene and chloroform appeared at levels that cannot be ignored for both children and adults. Conclusion: Currently, in the domestic context, health hazard assessments are conducted based on the regulations outlined in the "Environmental Health Act" where if the hazard index exceeds a certain threshold, it is considered to pose a health risk. The anticipated expansion of the list of substances subject to the chemical discharge plan to 415 types by 2030 suggests the need for efficient management within workplaces. In instances where the hazard index surpasses the threshold in health hazard assessments, it is judged that effective chemical management can be achieved by prioritizing based on considerations of background concentration and predicted concentration through atmospheric dispersion modeling.