• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.135-139
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• 2002

Yeast cells respond to condition of amino acid starvation by synthesizing GCN4, a typical eukaryotic transcriptional activator, which regulates the expression of many amino acids biosynthetic genes. By introducing point mutations in the DNA binding domain of GCN4, mutants with normal DNA binding activity but defective in transcriptional activity were isolated to identify unknown proteins that could suppress the mutant phenotype under an amino acid depletion condition. As a result, SSB(Stress-Seventy B) subfamily proteins were identified as suppressors of mutant GCN4. SSB proteins were known as a member of yeast hsp70 family that probably aids passage of nascent chain through ribosomes. Among them, the mechanism of suppression by SSB2 on the defective GCN4 mutant strains is under investigation. Gcn4p directly interacts with Ssb2p through the basic DNA binding domain of GCN4. It suggests the possibility that physical interaction might induce the transcriptional activation of Gcn4p.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1810-1812
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• 2002

This test was performed to assess the insulation deterioration condition of the stator winding of Chung-Ju hydrogenerator #4 and Dae-Cheong hydrogenerator #2 which had been in service after being constructed 1980. The insulation diagnostic tests include resistance polarization index(P.I.) AC current, dissipation factor(Tan ${\delta}$) and partial discharges ($Q_{max}$). The results of diagnostic tests were compared to factory test measurements.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.12 no.1
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• pp.13-23
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• 2008

In [7, 8], they proposed a new singular function(NSF) method to compute singular solutions of Poisson equations on a polygonal domain with re-entrant angles. Singularities are eliminated and only the regular part of the solution that is in $H^2$ is computed. The stress intensity factor and the solution can be computed as a post processing step. This method was extended to the interface problem and Poisson equations with the mixed boundary condition. In this paper, we give NSF method for the Helmholtz equations ${\Delta}u+Ku=f$ with homogeneous Dirichlet boundary condition. Examples with a singular point are given with numerical results.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.5
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• pp.451-457
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• 2014

Surface roughness of mechanical components is an important factor which affects the tribological phenomena. Various surface patterns have been applied to surfaces to improve the tribological characteristics of mechanical components. In this work, the friction reduction effect of micropatterns on silicon was investigated. For this purpose, micro-dimple patterns were fabricated on silicon wafer by DRIE process. In the friction experiments silicone oil was used as lubricant. Also, the lubricant was cleaned to simulate a lubricant depleted condition. In depleted lubricated condition, friction coefficient of micro-pattern specimens was lower than specimens without micro-patterns. It was found that friction reduction effect of micro-pattern could be successfully maintained even after cleaning the lubricant on the surface.

• Journal of the Ergonomics Society of Korea
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• v.26 no.2
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• pp.89-102
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• 2007

Generally, it is well known that driving in tunnel imposes large burden to driver because of spatial constraint, limited visual field and so on. And such a burden of driver result in high accident occurrence. In this reason, studies dealing with features of driving and traffic flow in tunnel have been performed. However, information about characteristics of drivers and traffic in a very long tunnel is not accumulated yet. The purpose of this study is to identify the relations between tunnel length and burden of driver, driving patterns, traffic flow characteristics using the tunnel simulator that realizing various tunnel situations. For this, the tunnel simulation program was developed along 11km-length section. And biological data of 10 subjects gained from driving condition in simulation program was analyzed and compared with the result of real driving condition.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.101-106
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• 2009

The unsafe act and unsafe condition is due to human error that experience 80% of safety accidents. Accordingly, one of the most important issues to reduce industrial accidents as a whole, is how to reduce the accident rate by the human error. Therefore, this paper describes the development of quantitative risk assessment (QRA) model by ergonomics for reform of safety consciousness on the semiconductor industry. Unconsciousness, disregard, ignorance, recklessness, and stress among the human factors are selected for conscious reform. Finally, the QRA model is efficiently expected to contribute towards improving continuous self-safety and health and safety culture campaign in order to prevent industrial accidents.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.89-91
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• 2007

In this paper, we developed DSP based control system to automatically open and close passive filter, which is used to reduce harmonics, according to operating condition of loads. Passive filter control system automatically open and close each branch of filter according to working conditions of loads by sending signals to open and close installation of passive filter after measuring and monitoring voltage, current, harmonics, reactive power, power factor and so on. We verified it's performance by connecting control system with passive filter in the power line using the 100[HP] d.c. motor drive, opening and closing passive filter according to operation condition of motor, and measuring harmonics and reactive power, etc.

• Science of Emotion and Sensibility
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• v.11 no.2
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• pp.193-206
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• 2008

This paper describes to experiments on the estimation of tourist images in Busan. Preliminary tasks were performed to find out the condition of tourism souvenir and products proper to ocean city with situation in Busan. This survey analyzed by factor analysis taken in local residents, foreigners and other city. Result of factor analysis shows that the local residents and others think of Busan as similar image both. Outsider recognized Busan to tourist attractions of seaside environment and tourist facilities, and have good image of sightseeing and shopping in city. The local people remind Busan as progressive, feels sweet, activity, friendly image beside that foreign tourist remind as clean, modern, abundant, and others think as stable, changing, novelty, friendly. To abstract 8 factors among the images, take out of relevance to condition of tourist and image factors. Important factors for development of tourist industry in Busan are a feeling safe, clean, novelty in priority. And find way that enhancing image to abundant, friendly, activity were proper to tourist industry.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2001.11a
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• pp.100-100
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• 2001

Hypoxia is a pathophysiological condition that occurs during injury, ischemia, and stroke. Hypoxic stress induces the expression of genes associated with increased energy flux, including the glucose transporters Glutl and Glut3, several glycolytic enzymes, nitric oxide synthase, erythropoietin and vascular endothelial growth factor. Induction of these genes is mediated by a common basic helix-loop-helix PAS transcription complex, the hypoxia-inducible factor-l${\alpha}$ (HIF-1${\alpha}$)/ aryl hydrocarbon receptor nuclear translocator (ARNT). Insulin plays a central role in regulating metabolic pathways associated with energy storage and utilization. It triggers the conversion of glucose into glycogen and triglycerides and inhibits gluconeogenesis. Insulin also induced hypoxia-induced genes. However the underlying mechanism is unestablished. Here, we study the possibility that transcription factor HIF-1${\alpha}$ is involved in insulin-induced gene expression. We investigate the mechanism that regulates hypoxia-inducible gene expression In response to insulin We demonstrate that insulin increases the transcription of hypoxia- inducible gene. Insulin-induced transcription is not detected in Arnt defective cell lines. Under hypoxic condition, HIF- l${\alpha}$ stabilizes but does not under insulin treatment. Insulin-induced gene expression is inhibited by presence of PI-3 kinase inhibitor and Akt dominant negative mutant, whereas hypoxia-induced gene expression is not. ROS inhibitor differently affects insulin-induced gene expressions and hypoxia-induced gene expressions. Our results demonstrate that insulin also regulates hypoxia-inducible gene expression and this process is dependent on Arnt. However we suggest HIF-l${\alpha}$ is not involved insulin-induced gene expression and insulin- and hypoxia- induces same target genes via different signaling pathway.

• Journal of Korean Elementary Science Education
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• v.24 no.5
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• pp.531-538
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• 2005

The primary purpose of the study was to investigate the degree of difficulty and the causes of the difficulties in science instruction reported by elementary teachers and students. The secondary purpose was to suggest the effective methods to both of them to improve the efficiency of science instruction. For this study, the survey was carried out on 322 students and 156 teachers in the 3rd, 4th, and 5th grades. The questionnaires consisted of interest, difficulty and its factors. The results of this investigation are summarized as follows; 1. Teachers had relatively higher interest than students in science instruction content(textbook). Furthermore, the units that teachers showed interest differed from those that students had. This means that there is a significant difference of interest in instruction process between teachers and students. 2. Teachers felt much higher difficulty than students in the content of science instruction. This shows that the degree of interest might have little relation with that of difficulty, and that teaching of science seemed more difficult than teaming. Moreover, there was a difference of difficulty in the units between the teachers and students. The result shows a distinctive difference of difficulty in 8 units of the 3rd grade, 9 units n the 4th grade, and 12 units in the 5th grade (p<.05, p<.001, p<.005, respectively). It means that the difficulty depended on the units. 3. Students responded that they are responsible for difficulty factors of teaming, otherwise teachers thought that students are responsible for it, when the factors were divided into student factor, teacher factor, and curriculum factor. 4. Students demanded many experiments in the lab as well as easy and interesting instructions in order to reduce the degree of difficulty and to improve the condition of science instructions. However, teachers demanded the expansion of experimental equipments and materials as well as the improvement of the lab condition.