• Journal of the Korean Applied Science and Technology
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• v.25 no.3
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• pp.322-331
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• 2008

In order to synthesize high-solid coatings, acrylic resins (HSAs) containing 90% solid content were first synthesized, then the synthesized HSAs were cured with a curing agent, isocyanate, at room temperature to obtain high-solid coatings. In the HSAs synthesis, conversion was in a range of $82{\sim}87%$, and viscosities and number-averaged molecular weight ($M_n$) of the HSAs were in a range of $4380{\sim}8010$ cP and $1540{\sim}1660$, respectively. From the correlation between $T_g$ value, viscosity and $M_n$, it was found that, with increasing $T_g$ value, viscosity increases rapidly and molecular weight increases slowly. From the visco-elasity measured by the pendulum method, it was found that the curing time decreased with increasing $T_g$ values. From the tests of physical properties of the coatings' film, $60^{\circ}$ specular gloss, impact resistance and heat resistance were proved to be good and pencil hardness, drying time and pot-life were proved to be poor.

• Neonatal Medicine
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• v.28 no.1
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• pp.14-21
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• 2021

Purpose: Premature infants have immature respiratory control and cerebral autoregulation. We aimed to investigate changes in cerebral oxygenation during apnea with and without peripheral oxygen desaturation in premature infants. Methods: This prospective observational study was conducted at Inha University Hospital. Near-infrared spectroscopy (NIRS)-monitored regional cerebral oxygen saturation (rScO₂) and pulse oximeter-monitored peripheral oxygen saturation (SpO₂) were assessed during the first week of life in 16 stable, spontaneously breathing preterm infants. Apneic episodes that lasted for ≥20 seconds or were accompanied by desaturation or bradycardia were included for analysis. The average rScO₂ value during the 5-minute prior to apnea (baseline), the lowest rScO₂ value following apnea (nadir), the time to recover to baseline (recovery time), the area under the curve (AUC), and the overshoot above the baseline after recovery were analyzed. Results: The median gestational age and birth weight of the infants were 29.2 weeks (interquartile range [IQR], 28.5 to 30.5) and 1,130 g (IQR, 985 to 1,245), respectively. A total of 73 apneic episodes were recorded at a median postnatal age of 2 days (IQR, 1 to 4). The rScO₂ decreased significantly following apneic episodes regardless accompanied desaturation. There were no differences in baseline, nadir, or overshoot rScO₂ between the two groups. However, the rScO₂ AUC for apnea with desaturation was significantly higher than that for apnea without desaturation. Conclusion: Cerebral oxygenation can significantly decrease during apnea, especially when accompanied by reduced SpO₂. These results add the evidence for the clinical utility of NIRS in monitoring premature infants.

• Structural Engineering and Mechanics
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• v.16 no.6
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• pp.749-769
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• 2003

The structural deterioration of concrete structures due to reinforcement corrosion is a major worldwide problem. Service life of the age-degraded concrete structures is governed by the protective action provided by the cover concrete against the susceptibility of the reinforcement to the corrosive environment. The corrosion of steel would result in the various corrosion products, which depending on the level of the oxidation may have much greater volume than the original iron that gets consumed by the process of corrosion. This volume expansion would be responsible for exerting the expansive radial pressure at the steel-concrete interface resulting in the development of hoop tensile stresses in the surrounding cover concrete. Once the maximum hoop tensile stress exceeds the tensile strength of the concrete, cracking of cover concrete would take place. The cracking begins at the steel-concrete interface and propagates outwards and eventually resulting in the through cracking of the cover concrete. The cover cracking would indicate the loss of the service life for the corrosion-affected structures. In the present paper, analytical models have been developed considering the residual strength of the cracked concrete and the stiffness provided by the combination of the reinforcement and expansive corrosion products. The problem is modeled as a boundary value problem and the governing equations are expressed in terms of the radial displacement. The analytical solutions are presented considering a simple 2-zone model for the cover concrete viz. cracked or uncracked. A sensitivity analysis has also been carried out to show the influence of the various parameters of the proposed models. The time to cover cracking is found to be function of initial material properties of the cover concrete and reinforcement plus corrosion products combine, type of rust products, rate of corrosion and the residual strength of the cover concrete. The calculated cracking times are correlated against the published experimental and analytical reference data.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.1
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• pp.64-73
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• 2010

This study was conducted to modify the surface properties of papers by formation of hydrophobic self-assembled monolayer(SAM) on paper surface with silanes. A base paper I(0.5% AKD) and base paper II(1.0-1.5% AKD) were reacted with silanes(PFDTES, DMDCS, MODDCS) by immersion method and vapor deposition method. Hydrophobic SAMs(contact angle value>$120^{\circ}C$) were obtained on all papers after treatment with $10^{\mu}l$ PFDTES for 15min, with $50^{\mu}l$ DMDCS for 30min, with $50^{\mu}l$ MODDCS for 300min. When applying PFDTES to paper surface, lower silane concentration and shorter reaction time were required, whereas MODDCS with long alkyl chain required the longest reaction time of 300min. The st$\ddot{o}$ckight sizing degree of silane treated papers were increased between 105sec(base paper I) and 130sec(base paper II). The wet tensile strength of PFDTES-treated base papers(I, II) increased by 10-34% after SAM formation. However, the wet tensile strength of the DMDCS-treated base paper(I) was found to decrease from 0.067kN/m to 0.038kN/m; this may due to the cellulose degrading as a result of generated hydrogen chloride when hydroxyl group of cellulose were reacted with DMDCS. No apparent changes of PPS roughness on silane-treated papers are observed. The ATR-IR spectrum showed absorption peak located at 465 and 1200cm-1 which can be assigned to the Si-O-C asymmetric stretching and Si-O-C bonds, respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.109-113
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• 2016

In this paper, we propose efficient LED lighting control algorithm using a David star magic square. Such algorithms increases the power reduction, the heat efficiency and LED life cycle and the efficiency of the LED lighting control consumption. Lighting system using existing Magic square algorithm could be reduced to increase the heat efficiency of the LED because the LED lighting time of the reduced cross-lighting. but it has a limit to the lighting control. If should apply the this proposed algorithm, can reduces power consumption and increases LED life-cycle, heat efficiency of LED lighting module and efficiency of the lighting control of the LED. This paper proposed that algorithm is by using a David star magic square on the LED Matrix. Divided into twelve areas to move the pattern in constant time interval, to perform the cross rotation and inversion techniques to thereby light up. In this paper proposed algorithm of this paper was compared with existing Magic square approach. As a result, power consumption and heat-value and luminous flux was reduced as the conventional lighting system. And, the LED lighting control increase the efficiency.

• Journal of Family Resource Management and Policy Review
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• v.24 no.1
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• pp.41-53
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• 2020

The purpose of this study was to identify the factors that affect middle-old aged housewives' participation in lifelong learning as a part of human resource development. Through purposive sampling, the study recruited 163 full-time housewives over age 40 years who live in C City. As a result, first, 87.1 percent of all respondents, or 142, said they were willing to participate in lifelong learning in the future. There was no statistically significant difference in the results of cross-checking by age, educational background and monthly household income variables. Additionally, we used cluster analysis to measure differences in participation intentions according to the perception of human resource development of middle-old aged full-time housewives. The perception variable of lifelong learning is: First, Cognitive degree, second, importance, third, activation awareness. Cluster 1(n=16) was divided into generally low-perception types, such as cognitive degree, importance, and life-long learning activation of the C city, while Cluster 2(n=61) was classified as a type of person who thinks that lifelong learning is important to life and Cluster 3(n=86) was generally classified as a type with a higher lifelong learning perception. and we found that there was no difference in the intention to participate in lifelong learning by all cluster Lastly, we found that participants who valued human resource development scored significantly higher on measures of cognition than those who did not value it. Based on these results, we advocates social change that encourages the cultivation of talent through lifelong learning programs that can positively affect one's unique identity, not just wife and mother, and provide opportunities for self-development.

• Journal of the Korean Society of Food Culture
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• v.12 no.2
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• pp.195-200
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• 1997

The purposes of this study were to investigate the Maillard reactions of some oligosaccharides with lysine and the antioxidative effects of the ethanol extracts from their reaction mixtures on the soybean oil. The Maillard reactions were carried out of 2% oligosaccharides such as palatinose (PN), fructooligosaccharide (FO), isomaltooligosaccharide (IMO) with 2% lysine (L) for 24 hours heating at 60, 80, $100^{\circ}C$. The color intensity of Maillard reaction mixtures were determined by UV-VIS spectrophotometer upon reaction time and temperature. And the antioxidative effects on the soybean oil of each ethanol extract from Maillard reaction mixture of each oligosaccharide were measured by peroxide value (POV). POV's of soybean oil including reaction extracts were determined regularly every 2 days during 20 days storaged at $60{\pm}1^{\circ}C$. The results were obtained as follows: 1. The color intensity of the Maillard reaction mixtures were raised highly as the browning temperature and time increased. The color intensity of PN L browning mixture was the highest. The order of high color intensity at $100^{\circ}C$ was PN L>FO L>Glu L>IMO L. 2. Comparing the antioxidative effect of Maillard reaction product (at $100^{\circ}C$, for 12 hours) of each oligosaccharide to that of BHT and TBHQ, the order of high antioxidative effect was TBHQ>IMO L>BHT>Glu L>PN L>FO L. 3. From these results, it was known that PN L shown as high brown color intensity was appeared low antioxidative effect, while IMO L shown as low brown color intensity was appeared high antioxidative effect. So, it was recognized that there was no relation between brown color intensity and antioxidative effect.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.415-418
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• 2017

Recently, the demand for energy efficiency improvement technology through the connection of waste heat energy and SmartGrid has been increasing. Thus, investments for the cultivation of high value crops and produce is increasing through research aimed at synthetic technology in real-time utilization of smart farms and waste heat energy with the concept of using container greenhouses and plant factories. In this aspect, we have carried out research on a practical application technology that will help farmers to increase the economic effectiveness of LED based plant factories in terms of energy efficiency. This can provide opportunities to connect with the large scale automated smart farms in the future. In this study, we focused on the economic effectiveness of crop cultivation using cooling technology in a container greenhouse through waste heat energy. Hereafter, in order to further advance the technology of real-time monitoring/control of the absorption chiller which is used through the container greenhouses and waste heat energy by using IOT, we would like to propose research on new ideas of agricultural technology that can maximize the utility of cooling energy by operating a mobile gateway based on Raspberry PI.

• Journal of Intelligence and Information Systems
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• v.12 no.4
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• pp.109-126
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• 2006

An effective customer classification has been essential for the successful customer relationship management. The typical customer rating is carried out by the proportionally allocating the customers into classes in terms of their life time values. However, since this method does not accurately reflect the homogeneity within a class along with the heterogeneity between classes, there would be many problems incurred due to the misclassification. This paper suggests a new method of rating customer using Holistic profit technique, and validates the new method using the customer data provided by an insurance company. Holistic profit is one of the methods used for deciding the cutoff score in screening the loan application. By rating customers using the proposed techniques, insurance companies could effectively perform customer relationship management and diverse marketing activities.

• Journal of agriculture & life science
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• v.53 no.3
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• pp.17-26
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• 2019

Chamaecyparis obtusa is one of the economical conifers planted in Korea due to its good quality timber and wood characteristics. Individuals of C. obtusa containing high terpenes (HT) and low terpenes (LT) were selected for by colorimetric method. The HT of C. obtusa was delayed in wilting against various abiotic stresses compared to the LT plants. The HT group exposed to UV did not significant influence the chlorophyll content, and the chlorophyll value was higher in the HT group than the LT group. Also, chilling treatment (5℃) did not significant influence on the chlorophyll content. However treatment at -4℃ showed relatively low chlorophyll content in the LT group than the HT group. Plants exposure to high temperature was not a difference between the HT and the LT group. However, treatment at 38℃ influenced the chlorophyll content that was increased exposure time-dependently. In salt treatments, chlorophyll in the HT group was lower at high concentrations (300 and 500 mM) of NaCl. However, chlorophyll content increased to slightly in treatment time-dependently, which is 6.7% to 40%. H2O2 treatment has been a negative effect on the chlorophyll content in the HT group. All concentration of H2O2 decreased the chlorophyll content of 5% to 35%. Plants containing high terpenoids were resisted against some abiotic stress such as salt and H2O2. Our results implied that terpenoids could cause various abiotic stress resistance. These results could be utilized for efficient management and biomass production during forest silvicultures.