• International Journal of Reliability and Applications
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• v.7 no.1
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• pp.27-39
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• 2006

Many real world cases in material failure analysis do not follow perfectly the normal distribution. Forcing of the normality assumption may lead to inaccurate predictions and poor product quality. We examine the failure process of the internal bond (IB or tensile strength) of medium density fiberboard (MDF). We propose a forced censoring technique that closer fits the lower tails of strength distributions and better estimates extremely smaller percentiles, which may be valuable to continuous quality improvement initiatives. Further analyses are performed to build an accelerated common-shaped Weibull model for different product types using the $JMP^{(R)}$ Survival and Reliability platform. In this paper, a forced censoring technique is implemented for the first time as a software module, using $JMP^{(R)}$ Scripting Language (JSL) to expedite data processing, which is crucial for real-time manufacturing settings. Also, we use JSL to automate the task of fitting an accelerated Weibull model and testing model homogeneity in the shape parameter. Finally, a package script is written to readily provide field engineers customized reporting for model visualization, parameter estimation, and percentile forecasting. Our approach may be more accurate for product conformance evaluation, plus help reduce the cost of destructive testing and data management due to reduced frequency of testing. It may also be valuable for preventing field failure and improved product safety even when destructive testing is not reduced by yielding higher precision intervals at the same confidence level.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2005.11a
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• pp.17-30
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• 2005

Lycopene is the red-coloured carotenoid predominantly found in tomato fruit and one of the major carotenoids in the diets of North American and Europeans. Interest in lycopene is growing rapidly following the recent publication of its effects as a natural antioxidant and prevention of cardiovascular disease and cancers. Lycopene, a polyene hydrocarbon carotenoid haying 13 double bond, of which 11 are conjugated double bonds in a linear array exhibits a strong antioxidant property almost twice as strong as that of ${\beta}$-carotene. Lycopene has been shown in recent epidemiological and experimental studies to protect against oxidative damage of DNA which plays an important part in development of various cancer. Lycopene also contribute towards reducing the risk of cardiovascular diseases by preventing oxidation of low-density lipoprotein(LDL) cholesterol. This review summarize our knowledge and the current understanding of lycopene in human health as well as the results of experiments we conducted. We conducted experiments for investigating the effects of antioxidant in broiler and the possibilities of production of high quality eggs containing lycopene by the dietary lycopene supplementation with synthetic lycopene or tomato paste. The results shows that thiobarbituric acid reaction substances(TBARS) values in process of LDL oxidation in blood serum of broiler were significantly decreased by dietary lycopene and tomato paste. The dietary lycopene supplementation resulted in improved egg yolk color and in decreased the malondialdehyde (MDA) of egg yolk after 4 wk of storage at room temperature significantly(P<0.05). The dietary tomato paste was more effective in the MDA reduction compared to the lycopene(P<0.05). The contents of lycopene in egg yolk of the lycopene supplementation groups were significantly higher than those of the control group.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.1
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• pp.41-45
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• 2014

We have investigated the passivation property of $SiN_x$ and $SiO_2$ thin films formed using various process conditions for the application of crystalline Si solar cells. An increase in the thickness of $SiN_x$ deposited using plasma enhanced chemical vapor deposition (PECVD) led to the improvement of passivation quality. This could be associated with the passivation of Si dangling bonds by hydrogen atoms which were supplied during PECVD deposition. The $SiO_2$ thin films grown using dry oxidation process exhibited better passivation behavior than those using wet oxidation process, implying the dry oxidation process was more effective in the formation of high quality $SiO_2$ thin films. The relative effective life time gradually decreased with increasing dry oxidation temperature. Such a degradation of passivation behavior could be attributed to the increase in interface trap density caused by thermal damages.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.477-483
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• 2020

The rehabilitation methods used in existing concrete box structures rely on the method of attaching the repair material to the section of the structure with a spray equipment. In the case of ceiling or wall parts, the adhesion force to the repair material may be reduced by the gravity and dead load after construction. In subway structures, vibration causes a problem that reduces the initial adhesion. Supplementary measures are needed as the quality of repair varies depending on the worker's proficiency and construction environment. In this study, mechanical pressurization equipment was developed that can apply a certain pressure after construction of a repairwork to solve problems such as reduction of adhesion of repair materials by gravity and variation of repair quality by labor work. To find out the effect of the pressurized equipment, a chamber similar to the field conditions was constructed to measure the attachment strength different from the pressurized condition, the section, and the environmental conditions. The pressurization differed from the other parts, but the adhesion strength of up to 70% was increased.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.29.1-29.1
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• 2009

Fabrication of good quality P-type GaN remained as a challenge for many years which hindered the III-V nitrides from yielding visible light emitting devices. Firstly Amano et al succeeded in obtaining P-type GaN films using Mg doping and post Low Energy Electron Beam Irradiation (LEEBI) treatment. However only few region of the P-GaN was activated by LEEBI treatment. Later Nakamura et al succeeded in producing good quality P-GaN by thermal annealing method in which the as deposited P-GaN samples were annealed in N2 ambient at temperatures above $600^{\circ}C$. The carrier concentration of N type and P-type GaN differs by one order which have a major effect in AlGaN based deep UV-LED fabrication. So increasing the P-type GaN concentration becomes necessary. In this study we have proposed a novel method of activating P-type GaN by electrochemical potentiostatic method. Hydrogen bond in the Mg-H complexes of the P-type GaN is removed by electrochemical reaction using KOH solution as an electrolyte solution. Full structure LED sample grown by MOCVD serves as anode and platinum electrode serves as cathode. Experiments are performed by varying KOH concentration, process time and applied voltage. Secondary Ion Mass Spectroscopy (SIMS) analysis is performed to determine the hydrogen concentration in the P-GaN sample activated by annealing and electrochemical method. Results suggest that the hydrogen concentration is lesser in P-GaN sample activated by electrochemical method than conventional annealing method. The output power of the LED is also enhanced for full structure samples with electrochemical activated P-GaN. Thus we propose an efficient method for P-GaN activation by electrochemical reaction. 30% improvement in light output is obtained by electrochemical activation method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.3
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• pp.233-240
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• 2023

p-type Tunnel Oxide Passivating Contacts (TOPCon) solar cell is fabricated with a poly-Si/SiO_x structure. It simultaneously achieves surface passivation and enhances the carriers' selective collection, which is a promising technology for conventional solar cells. The quality of passivation is depended on the quality of the tunnel oxide layer at the interface with the c-Si wafer, which is affected by the bond of SiO formed during the subsequent annealing process. The highest cell efficiency reported to date for the laboratory scale has increased to 26.1%, fabricated by the Institute for Solar Energy Research. The cells used a p-type float zone silicon with an interdigitated back contact (IBC) structure that fabricates poly-Si and SiO_x layer achieves the highest implied open-circuit voltage (iV_oc) is 750 mV, and the highest level of edge passivation is 40%. This review presents an overview of p-type TOPCon technologies, including the ultra-thin silicon oxide layer (SiO_x) and poly-silicon layer (poly-Si), as well as the advancement of the SiO_x and poly-Si layers. Subsequently, the limitations of improving efficiency are discussed in detail. Consequently, it is expected to provide a basis for the simplification of industrial mass production.

• Korea Science and Art Forum
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• v.19
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• pp.623-633
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• 2015

Use of technology through utilization of ICT (Information Communication Technology) in field study area is rapidly increasing. Thus, when applying ICT to experiential education, apart from experiential education contents in simple form, the demand for new high quality contents is increasing considering change in education paradigm focusing on creativity. As a result, high quality interactive experiential education content for developing self-directed future talents is required. As a result of this, the development of ARD-based ICT experiential education content system that enhances learning effect of students by integrating ARD-based (Augmented Reality Display) ICT and experiential education to promote existence and immersion is being tested. This paper aims to improve efficacy and achieve vitalization through case analysis of AR-based ICT experiential education content. As a result of case analysis, the composition of content for improving education content included 1) constant securing and strengthening of experiential education content, 2) necessity for development of participating education content by diverse age groups, 3) development of differentiated ICT experiential education content, and 4) securing professional manpower and development of content in connection with education process. Therefore, with the efficacy of ARD-based ICT experiential education content, this study can first, enhance bond between students, second, enable self-directed learning, third, increase practical understanding in contents that were difficult to control by textbook contents, and fourth, increase interest and immersion in learning. Therefore, the contents on new converging technology that can maximize the development of constant content and cooperation between ICT technology and pedagogy for educating creativity and autonomy of ICT experiential education content.

• Journal of Korean Society for Quality Management
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• v.51 no.2
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• pp.171-184
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• 2023

Purpose: First, this paper suggests an alternative approach to find optimal portfolio (stocks, bonds and ESG stocks) under the maximizing utility of investors. Second, we include ESG stocks in our optimal portfolio, and compare improvement of welfares in the case with and without ESG stocks in portfolio. Methods: Our main method of analysis follows Brennan et al(2002), designed under the continuous time framework. We assume that the dynamics of stock price follow the Geometric Brownian Motion (GBM) while the short rate have the Vasicek model. For the utility function of investors, we use the Power Utility Function, which commonly used in financial studies. The optimal portfolio and welfares are derived in the partial equilibrium. The parameters are estimated by using Kalman filter and ordinary least square method. Results: During the overall analysis period, the portfolio including ESG, did not show clear welfare improvement. In 2017, it has slightly exceeded this benchmark 1, showing the possibility of improvement, but the ESG stocks we selected have not strongly shown statistically significant welfare improvement results. This paper showed that the factors affecting optimal asset allocation and welfare improvement were different each other. We also found that the proportion of optimal asset allocation was affected by factors such as asset return, volatility, and inverse correlation between stocks and bonds, similar to traditional financial theory. Conclusion: The portfolio with ESG investment did not show significant results in welfare improvement is due to that 1) the KRX ESG Leaders 150 selected in our study is an index based on ESG integrated scores, which are designed to affect stability rather than profitability. And 2) Korea has a short history of ESG investment. During the limited analysis period, the performance of stock-related assets was inferior to bond assets at the time of the interest rate drop.

• Journal of Marine Bioscience and Biotechnology
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• v.7 no.1
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• pp.1-10
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• 2015

Bio diesel has advantages to reduce GHG(Greenhouse Gas) compare with the fossil fuel by using oil comes from plant/animal sources and even waste such as used cook oil. The diversity of energy feeds brings the positive effects to secure the national energy mix. In this circumstance, micro-algae is one of the prospective source, though some technical barriers. We analyzed the bio diesel which was derived from Dunaliella tertiolecta LB999 through the BD100 quality specifications designated by the law. From that result, it is revealed that the oxidation stability is one of the properties to be improved. In order to find the reason for low oxidation stability, we analyzed the oxidation tendency of each FAME components through some methods(EN 14111, EN14112, EN16091). In this study, we could find the higher double bond FAME portion, the more oxidative property(C18:1${\ll}C18:3$) in bio diesel and main unsaturated FAME group is acted as the key component deciding the bio diesel's oxidation stability. It is proved experimentally that C18:3 FAME are oxidized easily under the modified accelerated oxidation test. We also figure out low molecular weight hydrocarbon and FAME were founded as a result of thermal degradation. Some alcohol and aldehydes were also made by FAME oxidation. In conclusion, it is necessary to find the way to improve the micro-algal bio diesel's oxidation stability.

• Culinary science and hospitality research
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• v.17 no.4
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• pp.316-325
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• 2011

The property of deep frying oil is one of die important factors in fried food quality. The purpose of this study is to identify die quality of deep frying oil in continuous usages for 4 days by two types of fryers: traditional and modified fryers. After frying polk cutlets, die flying oil was kept not only for several physical analyses such as color, viscosity, and water content but also for quality analyses of flying oil such as free fatty acid, double bond changes and oxidative rancidity formation. The fried oil by a traditional flyer was significantly increased in die physical values of color and viscosity than that by a modified fryer. In die acid value, the fried oil by a traditional fryer was significantly increased in free fatty acid than that by a modified fryer while die iodine value was significantly decreased in die fried oil by a traditional fryer when compared to control oil and fried oil by a modified fryer. In die peroxide value as an indicator of primary oxidation products, die fried oil by both fryers was significantly increased till die second day but decreased in die value after die third day because of unstable hydroperoxides' decomposition. In die p-anicidine value as an indicator of secondary oxidation products, die fried oil in a traditional fryer was significantly increased in die value than that in a modified fry.