• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.562-569
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• 2022

The alarm monitoring technology applied to existing operating ships manages data items such as temperature and pressure with AMS (Alarm Monitoring System) and provides an alarm to the crew should these sensing data exceed the normal level range. In addition, the maintenance of existing ships follows the Planned Maintenance System (PMS). whereby the sensing data measured from the equipment is monitored and if it surpasses the set range, maintenance is performed through an alarm, or the corresponding part is replaced in advance after being used for a certain period of time regardless of whether the target device has a malfunction or not. To secure the reliability and operational safety of ship engine operation, it is necessary to enable advanced diagnosis and prediction based on real-time condition monitoring data. To do so, comprehensive measurement of actual ship data, creation of a database, and implementation of a condition diagnosis monitoring system for condition-based predictive maintenance of auxiliary equipment and piping must take place. Furthermore, the system should enable management of auxiliary equipment and piping status information based on a responsive web, and be optimized for screen and resolution so that it can be accessed and used by various mobile devices such as smartphones as well as for viewing on a PC on board. This update cost is low, and the management method is easy. In this paper, we propose CBM (Condition Based Management) technology, for autonomous ships. This core technology is used to identify abnormal phenomena through state diagnosis and monitoring of pumps and purifiers among ship auxiliary equipment, and seawater and steam pipes among pipes. It is intended to provide performance diagnosis and failure prediction of ship auxiliary equipment and piping for convergence analysis, and to support preventive maintenance decision-making.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.85-89
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• 2021

AlGaN-based UV-C light-emitting diodes (LEDs) were applied for p-type activation by electrochemical potentiostatic activation (EPA). The p-type activation efficiency was increased by removing hydrogen atoms through EPA treatment using a neutral Mg-H complex that causes high resistance and low conductivity. A neutral Mg-H complex is decomposed into Mg^- and H⁺ depending on the key parameters of solution, voltage, and time. The improved hole carrier concentration was confirmed by secondary ion mass spectroscopy (SIMS) analysis. This mechanism eventually improved the internal quantum efficiency (IQE), the light extraction efficiency, the leakage current value in the reverse current region, and junction temperature, resulting in better UV-C LED lifetime. For systematic analysis, SIMS, Etamax IQE system, integrating sphere, and current-voltage measurement system were used, and the results were compared with the existing N₂-annealing method.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.683-691
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• 2021

The purpose of this study is to measure the yield and to evaluate the physiological activity of Cannabis sativa seed(Hemp seed) extracts extracted using a density fluctuation supercritical carbon dioxide for each temperature condition-30℃(HSSE30), 45℃(HSSE45), 60℃(HSSE60), and to enable dissolution of the poorly water-soluble extracts by liposome formulation and to enhance the skin permeability. As a result of the yield measurement, HSSE60 showed the highest yield, and in the antioxidant activities, HSSE45 had the highest total polyphenol content, and showed the highest DPPH, ABTS+ radical scavenging activities at the highest concentration of the extracts. As a result of the antimicrobial susceptibility testing, a clear zone appeared only in the Propionibateium acnes strain. It was confirmed that particle size was reduced and the absolute value of the zeta potential increased in the case of the formulation in which the extracts were in liposomes than in the formulation in which the extracts were dissolved in deionized water, and the skin permeability was improved. Based on these experimental results, we confirmed the possibility of using the hemp seed supercritical carbon dioxide extracts, a poorly water-soluble extract, can be applied as a functional natural material for cosmetics.

• Clean Technology
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• v.15 no.4
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• pp.258-264
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• 2009

Thermodynamic measurements were performed to show the possibility of recovering $CO_2$ from fuel gas (the mixture of $CO_2$ and $H_2$) by forming gas hydrates with water where water was dispersed in the pores of silica gel particles having nominal 100 nm of pore diameter. The hydrate-phase equilibria for the ternary $CO_2+H_2$+water in pores were measured and $CO_2$ concentrations in vapor and hydrate phase were determined under the hydrate-vapor two phase region at constant 274.15 K. It was shown that the inhibition effect appeared due to silica gel pores, and the corresponding equilibrium dissociation pressures became higher than those of bulk water hydrates at a specific temperature. In addition, direct measurement of $CO_2$ content in the hydrate phase showed that the retrieved gas from the dissociation of hydrate contained more than 95 mol% of $CO_2$ when 42 mol% of $CO_2$ and balanced Hz mixture was applied. Compared with data obtained in case of bulk water hydrates, which showed just 83 mol% of $CO_2$ where 2-stage hydrate slurry reactor was intended to utilize this property, the hydrate formation in porous silica gel has enhanced the feasibility of $CO_2$ separation process. Hydrate formation as not for slurry but solid particle makes it possible to used fixed bed reactor, and can be a merit of well-understood technologies in the industrial field.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.3
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• pp.133-140
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• 2023

The performance of lithium ion batteries depends on the usage environment and the combination ratio of cathode materials. In order to develop a high-performance lithium-ion battery, it is necessary to manufacture the battery and measure its performance while varying the cathode material ratio. However, it takes a lot of time and money to directly develop batteries and measure their performance for all combinations of variables. Therefore, research to predict the performance of a battery using an artificial intelligence model has been actively conducted. However, since measurement experiments were conducted with the same battery in the existing published battery data, the cathode material combination ratio was fixed and was not included as a data attribute. In this paper, we define a training data model required to develop an artificial intelligence model that can predict battery performance according to the combination ratio of cathode materials. We analyzed the factors that can affect the performance of lithium-ion batteries and defined the mass of each cathode material and battery usage environment (cycle, current, temperature, time) as input data and the battery power and capacity as target data. In the battery data in different experimental environments, each battery data maintained a unique pattern, and the battery classification model showed that each battery was classified with an error of about 2%.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.5 no.5
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• pp.471-479
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• 2015

This study was conducted to make use of Korea Meteorological Administration(KMA)'s Automatic Weather Station(AWS) data to operate smart green greenhouse. A Web-based KMA AWS data receiving system using JAVA and APM_SETUP 8 on windows 7 platform was developed. The system was composed of server and client. The server program was developed by a Java application to receive weather data from the KMA every 30 minutes and to send the weather data to smart greenhouse. The client program was developed by a Java applets to receive the KMA AWS data from the server every 30 minutes through communicating with the server so that smart greenhouse could recognize the KMA AWS data as the ambient weather information. This system was evaluated by comparing with local weather data measured by Inc. Ezfarm. In case of ambient air temperature, it showed some difference between virtual data and measured data. But, the average absolute deviation of the difference has a little difference as less than 2.24℃. Therefore, the virtual weather data of the developed system was considered available as the ambient weather information of the smart greenhouse.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.11
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• pp.109-119
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• 2018

This study investigates the effect of urban and architectural forms on the microclimate in urban areas. It applies urban and architectural elements such as urban form and tissue and building form and characteristics as the main influences on the microclimate within urban area. Among the 23 Automated Weather Stations (AWS) installed within Seoul city by the Korea Meteorological Administration, 6 sites were selected for the analysis, based on their different urban and architectural characteristics, and actual measurements were conducted in August 2017 using individual AWS equipment. Also, the measurements of microclimate and urban and architectural elements within a 500m radius of the AWS measurement points were collected and analyzed. The result of the analysis shows that the microclimate elements, such as wind speed, solar radiation, and temperature, were affected by the direction of the streets, the width, depth, and height of the buildings, the topographic elevation and direction and the traffic volume. This study is expected to contribute to mitigating urban heat island effect and setting the foundation for sustainable cities through development of urban management methods and techniques including the relationship between built environment elements and microclimate.

• Composites Research
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• v.36 no.3
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• pp.186-192
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• 2023

Recently, in the field of railway vehicles, interest in the use of composite materials for weight reduction and transportation efficiency is increasing. Accordingly, research and commercialization development to apply composite materials to various vehicle parts are being actively conducted, and evaluation is conducted centering on post-measurement such as mechanical performance evaluation of finished products to verify quality when composite materials are applied. However, the analysis of heat and stress generated during the molding process of composite materials, which are factors that greatly affect manufacturing quality, is insufficient. Therefore, in this study, in order to verify the molding quality of composite parts for railway vehicles, the molding quality analysis was conducted for the two types of composite interior panels (laminate panel and sandwich panel) that are most actively used. To this end, temperature and strain changes were monitored during the molding process by using an FBG fiber optic sensor, which is easy to apply to the inside of the composite, and the residual strain value generated after molding was completed was measured. As a result, it was confirmed that overheating and excessive residual stress did not occur, thereby verifying the excellent molding quality of the composite interior panel for railway vehicles.

• Analytical Science and Technology
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• v.19 no.2
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• pp.149-154
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• 2006

A gas chromatography-mass spectrometric method was developed for the determination of formaldehyde in urine and saliva. In a 20 mL glass tube, 0.2 mL of urine or saliva was taken. Further, 1.8 mL of 0.1 M HCl, 0.1 mL of 2,000 mg/L 2,4-dinitrophenyl hydrazine and $20{\mu}l$ of 500 mg/L acetone-$d_6$ as internal standard were added in the tube and sealed tightly with cap. The solution was shaken for 20 min at room temperature and extracted using 4 mL of toluene. The extract was concentrated and redissolved with $100{\mu}l$ of acetonitrile, and then measured by gas chromatography-mass spectrometer (selected ion monitoring). The detection limit was 2.0 ng/mL and 0.5 ng/mL in saliva and urine, respectively. The calibration curves showed good linearity with r = 0.997 and 0.998 for saliva and urine, respectively. The method was used to analyze formaldehyde in rat urine after oral exposure. The developed method may be use ful to the monitoring for formaldehyde exposure in human.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.4
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• pp.291-298
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• 2023

In this study, a quantitative analysis method was developed using high-performance liquid chromatography (HPLC) to analyze the content of ceramide NP in lotion, cream, and cleanser formulations in cosmetics. The analysis was performed using a C18 column, and the mobile phase was set at a ratio of 70 : 30 for acetonitrile and methanol, the flow rate was set to 0.8 mL/min, and the column temperature was set to 20 ℃. The method was verified by analyzing specificity, linearity, limit of detection, limit of quantitation, accuracy, and precision in accordance with the ICH guidelines. As a result of validating the method, the linearity of the calibration curve was excellent (R² = 0.99984). The accuracy of the lotion, cream, and cleanser formulations was confirmed with a recovery rate ranging from 95.11% to 100.48%. The precision analysis showed a low relative standard deviation (RSD) of less than 0.26%. The limit of detection was 0.902 ㎍/mL, and the limit of quantitation was 2.733 ㎍/mL. Through this quantitative analysis method of ceramide NP applied in cosmetics, it is expected to assist in the quality control of products by enabling measurement even when it is difficult to separate the main peak due to the influence of interfering substances.