• Corrosion Science and Technology
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• v.12 no.5
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• pp.239-244
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• 2013

Marine equipment exposed to harsh environments requires not only excellent corrosion resistance but also improvement of physical characteristics against natural material degradation. With growing interests in ocean energy resources, the higher reliability for marine equipment has become more important in terms of material characteristics. ALBC3 alloy represents excellent corrosion resistance and is widely used in corrosive environments. However, cavitation damage occurs frequently due to its poor durability in high flow rate of marine environment. In this research, shot peening technology was employed as a surface modification with shot peening stand-off distance to mitigate cavitation damage. The effects of shot peening on extent of cavitation damage and weight loss were evaluated for both shot peened and non-peened specimens. The results revealed that the application of shot peeing decreased cavitation damage for all experimental conditions in comparison with the non-peened specimens. The optimum stand-off distance was determined to be 10 cm, since more than 35 % of cavitation damage reduction was observed.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.6
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• pp.65-78
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• 2023

In recent times, the frequency and intensity of natural disasters, such as heavy rains and typhoons, have been increasing due to the impacts of climate change. This has led to a rise in social and economic damages. Rural areas, in particular, possess limited disaster response capabilities due to their underdeveloped infrastructure and are highly vulnerable to flooding. Therefore, it is crucial to establish preventative and responsive measures. In this study, an Inventory-Based Flood Loss Estimation (IB-FLE) method utilizing high-resolution spatial information was developed for estimating flood-related losses in rural areas. Additionally, the developed approach was applied to a study area and compared with the Multidimensional Flood Damage Analysis (MD-FDA) method. Compared to the MD-FDA, the IB-FLE enables faster and more accurate estimation of flood damages and allows for the assessment of individual building and agricultural land losses using up-to-date information. The findings of this study are expected to contribute to the rational allocation of budgets for rural flood damage prevention and recovery, as well as enhancing disaster response capabilities.

• Culinary science and hospitality research
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• v.14 no.2
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• pp.286-292
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• 2008

The purpose of this study was to examine the effects of freezing and thawing methods on the quality of pork meat. The freezing methods for pork meat were the cryogenic freezing with liquid nitrogen gas, fast freezing at $-70^{\circ}C$ and normal freezing at $-20^{\circ}C$. The thawing methods were tested on low temperature thawing at refrigerative temperature($4^{\circ}C$), room temperature($20^{\circ}C$), high temperature($60^{\circ}C$) and using microwave. The quality of pork meat frozen by cryogenic methods was better than those of fast and normal freezing methods. The cooking hardness of pork meat frozen by cryogenic method showed the highest value as 1,898 g. In case of fast freezing, the hardness of pork meat was 1,472 g and that of normal frozen pork meat was 1,541 g. The high cooking hardness value of cryogenic frozen pork meat showed that the cryogenic freezing method made less freeze damage like textural softness. The drip-loss of pork meat thawed at refrigerative temperature($4^{\circ}C$), room temperature($20^{\circ}C$), high temperature($60^{\circ}C$) were shown lower than that of microwave thawing. The cooking hardness of pork meat that was thawed by microwave showed the lowest value among the thawing methods. The cryogenic freezing was the most useful freezing method for preserving quality, decreasing the freeze damage of pork meat. And thawing at refrigerative temperature was the most effective method to prevent quality loss and weight loss by drip-loss.

• Journal of Korean Vacuum Science & Technology
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• v.3 no.1
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• pp.1-9
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• 1999

This paper presents a newly enhanced damage model in Monte Carlo (MC) simulation for the accurate prediction of 3-Dimensional (3D) as-implanted impurity and point defect profiles induced by ion implantation in (100) crystal silicon. An empirical electronic energy loss model for B, BF2, As, P and Si self implant over the wide energy range has been proposed for the ULSI device technology and development. Our model shows very good agreement with the SIMS data over the wide energy range. In the damage accumulation, we considered the self-annealing effects by introducing our proposed non-linear recomvination probability function of each point defect for the computational efficiency. For the damage profiles, we compared the published RBS/channeling data with our results of phosphorus implants. Our damage model shows very reasonable agreement with the experiments for phosphorus implants.

• Korean Journal of Veterinary Research
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• v.39 no.1
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• pp.34-44
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• 1999

Ischemic damage in the selectively vulnerable populations of neurons is thought to be caused by an abnormal accumulation of intracellular calcium. It has been reported that the neurons, expressing specific calcium binding proteins, might effectively control intracellular calcium concentrations because of a high capacity to buffer intracellular calcium in the brain ischemic condition. It is uncertain that parvalbumin, one of the calcium binding proteins, can protect the neurons from the cerebral ischemic damage. Recently, treatment of kappa opioid agonists increased survival rate, improved neurological function, and decreased tissue damage under the cerebral ischemic condition. Many evidences indicate that these therapeutic effects might result from regulation of calcium concentration. This study was designed to analyze the changes of number in parvalbumin-positive neurons after cerebral ischemic damage according to timepoints after cerebral ischemic induction. In addition, we evaluated the effect of GR89696 (kappa opioid agonist) or naltrexone(non selective opioid antagonist) on the changes of number in parvalbumin expressing neurons under ischemic condition. Cerebral ischemia was induced by occluding the common carotid artery of experimental animals. The hippocampal areas were morphometrically analyzed at different time point after ischemic induction(1, 3, 5 days) by using immuno-histochemical technique and imaging analysis system. The number of parvalbumin-positive neurons in hippocampus was significantly reduced at 1 day after ischemia(p<0.05). Furthermore, the number of parvalbumin-immunoreactive neurons was dramatically reduced at 3 and 5 days after cerebral ischemic induction(p<0.05) as compared to 1 day group after ischemia, as well as sham control group. Significant reduction of parvalbumin positive neurons in CA1 region of hippocampus was observed at 1 day after cerebral ischemic induction. However, significant loss of MAP2 immunoreactivity was observed at 3 day after cerebral ischemia. The loss of parvalbumin-positive neurons and MAP2 immunoreactivity in CA1 region was prevented by pre-administration of GR89696 compared to that of saline-treated ischemic group. Furthermore, protective effect of GR89696 partially reversed by pre-treatment of naltrexone. These data indicate that parvalbumin-positive neurons more sensitively responded to cerebral ischemic damage than MAP2 protein. Moreover, this loss of parvalbumin-positive neurons was effectively prevented by the pretreatment of kappa opioid agonist. It was also suggested that the changes of number in parvalbumin-positive neurons could be used as the specific marker to analyze the degree of ischemic neuronal damage.

• BMB Reports
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• v.30 no.3
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• pp.188-193
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• 1997

Membrane lipid peroxidation processes yield products that may react with DNA to cause mutations. Lipid hydroperoxides from linoleic acid in the presence of transition metal ions caused strand breaks in plasmid DNA. DNA damage induced by reactive aldehydes known to be produced by decomposition of lipid hydroperoxides, such as 4-hydroxynonenal or rnalondialdehyde, was repaired by endonucleases and exonuclease III which resulted in the increase of single strand breaks in DNA. Lipid hydroperoxides as well as malondialdehyde and 4-hydroxynonenal also caused mutations in the pUC18 lacZ' gene when measured as a loss of ${\alpha}-cornplementation$. In conclusion. the lipid peroxidation could be an important intermediary event in DNA damage and mutation by oxidative stress.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.1
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• pp.69-77
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• 2009

Loss of human lives and properties including environmental damage due to large scale accidents requires change of our perception to marine safety. IMO is trying to re-establish overall marine safety system through long term plan such as GBS. Along this line, current regulation based safety evaluation is in process of changing into performance based methods, and for this transition, simulation based safety evaluation during design stage considering damage is highly necessary. In this paper, first, damage scenario is developed from IMO regulations and accident case studies. Then an integrated and simulation based safety evaluation prototype system considering both damage stability and structural safety is developed for the use during ship design process.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.1
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• pp.89-96
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• 2013

Recent DDoS attacks and private informations leaked show that everyday life is interwoven with cyberspace and we are becoming more vulnerable to cyber attacks. Therefore, a systematic understanding of cyber damage structure is very important and damage loss estimation method should be developed to establish solid cyber security protection system. In this study, economic loss caused by cyber attacks are surveyed based on the analysis of existing studies and try to develop a reasonable methods to estimate economic effects of cyber security protection in Korea. Potential economic loss of Korea by cyber attacks may be situated between 10 billion and 40 billion dollars. But more sophisticated system should be established to estimate economic effects of cyber protection for proper policy decision making.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.669-674
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• 2007

To develop a promising hybrid structural health monitoring (SHM) system, a combined use of structural vibration and electro-mechanical (EM) impedance is proposed. The hybrid SHM system is designed to use vibration characteristics as global index and EM impedance as local index. The proposed health monitoring scheme is implemented into prestressed concrete (PSC) girder bridges for which a series of damage scenarios are designed to simulate various prestress-loss situations at which the target bridges car experience during their service life. The measured experimental results, modal parameters and electro-magnetic impedance signatures, are carefully analyzed to recognize the occurrence of damage and furthermore to indicate its location.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.2
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• pp.290-299
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• 2017

Reconfigurable flight control using various kinds of adaptive control methods has been studied since the 1970s to enhance the survivability of aircraft in case of severe in-flight failure. Early studies were mainly focused on the failure of actuators. Recently, studies of reconfigurable flight controls that can accommodate complex damage (partial wing and tail loss) in conventional aircraft were reported. However, the partial wing loss effects on the aerodynamics of conventional type aircraft are quite different to those of BWB(blended wing body) aircraft. In this paper, a reconfigurable flight control algorithm was designed using a direct model reference adaptive method to overcome the instability caused by a complex damage of a BWB aircraft. A model reference adaptive control was incorporated into the inner loop rate control system enhancing the performance of the baseline control to cope with abrupt loss of stability. Gains of the model reference adaptive control were polled out using the Liapunov's stability theorem. Outer loop attitude autopilot was designed to manage roll and pitch of the BWB UAV as well. A 6-DOF dynamic model was built-up, where the normal flight can be made to switch to the damaged state abruptly reflecting the possible real flight situation. 22% of right wing loss as well as 25% loss for both vertical tail and rudder control surface were considered in this study. Static aerodynamic coefficients were obtained via wind tunnel test. Numerical simulations were conducted to demonstrate the performance of the reconfigurable flight control system.