• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.63-64
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• 2018

The construction industry is one of the most prolific disaster-prone industries, particularly those that suffer from falling disasters compared to other industries. The safety accident at the construction site leads to social problems caused by massive loss of life and property, so it needs to be extra careful. The reason why falls are the most frequent accidents of the types of construction accidents is due to the analysis of the risk factors of safety accidents and the development of various construction methods. Therefore, in this study, the accident case for the fallen victims of construction site was analyzed and the risk factor was selected. Based on the safety expert survey, an importance analysis was performed. In conclusion, this study analyzes various risk factors that affect the occurrence of falls, identifies the importance of each factor, and presents basic data for safety accident prevention activities.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2109-2118
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• 2011

The power system has to maintain its synchronism from transient disturbances and oscillations. To achieve this, the static var compensator(SVC), which is a flexible AC transmission system(FACTS), is applied to the power system. SVC using an advanced control algorithm improves the stability of power system. This paper is a study on design of SVC to improve harmonics and power factor of power plant. The proposed SVC analyzes harmonics, voltage drop and reactive power in real time. On the basis of the analysis of the data, the SVC using a switching control algorithm decreases harmonic signals and increases the power factor. The experimental results show that the proposed SVC enhances the stability of power system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.210-213
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• 2004

In this paper, we propose the passive PFC(Power Factor Correction) circuit of an electronic ballast with the constant power the detection circuit for 110 or 220 volt. The proposed PFC circuit is composed with the modified dither circuit and the input voltage detection circuit. We have concluded that the proposed method is the attractive method to improve of power factor for the electronic ballast with the input voltage regulation and it is a similar experimental results with other active power factor correction method using other PWM ICs.

• Structural Engineering and Mechanics
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• v.41 no.3
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• pp.339-348
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• 2012

The slope stability analysis is usually done using the methods of calculation to rupture. The problem lies in determining the critical failure surface and the corresponding factor of safety (FOS). To evaluate the slope stability by a method of limit equilibrium, there are linear and nonlinear methods. The linear methods are direct methods of calculation of FOS but nonlinear methods require an iterative process. The nonlinear simplified Bishop method's is popular because it can quickly calculate FOS for different slopes. This paper concerns the use of inverse analysis by genetic algorithm (GA) to find out the factor of safety for the slopes using the Bishop simplified method. The analysis is formulated to solve the nonlinear equilibrium equation and find the critical failure surface and the corresponding safety factor. The results obtained by this approach compared with those available in literature illustrate the effectiveness of this inverse method.

• Journal of Ginseng Research
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• v.42 no.1
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• pp.107-115
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• 2018

Background: Depression is one of the most commonly diagnosed neuropsychiatric diseases, but the underlying mechanism and medicine are not well-known. Although Panax ginseng has been reported to exert protective effects in various neurological studies, little information is available regarding its antidepressant effects. Methods: Here, we examined the antidepressant effect and underlying mechanism of P. ginseng extract (PGE) in a chronic restraint stress (CRS)-induced depression model in mice. Results: Oral administration of PGE for 14 d decreased immobility (depression-like behaviors) time in forced swim and tail suspended tests after CRS induction, which corresponded with attenuation of the levels of serum adrenocorticotropic hormone and corticosterone, as well as attenuated c-Fos expression in the amygdala. PGE enhanced messenger RNA expression level of brain-derived neurotrophic factor but ameliorated microglial activation and neuroinflammation (the level of messenger RNA and protein expression of cyclooxygenase-2 and inducible nitric oxide synthase) in the amygdala of mice after CRS induction. Interestingly, 14-d treatment with celecoxib, a selective cyclooxygenase-2 inhibitor, and $N_{\omega}$-nitro-L-arginine methyl ester hydrochloride, a selective inducible nitric oxide synthase inhibitor, attenuated depression-like behaviors after CRS induction. Additionally, PGE inhibited the upregulation of the nuclear factor erythroid 2 related factor 2 and heme oxygenase-1 pathways. Conclusion: Taken together, our findings suggest that PGE exerts antidepressant-like effect of CRS-induced depression by antineuroinflammatory and antioxidant (nuclear factor erythroid 2 related factor 2/heme oxygenase-1 activation) activities by inhibiting the hypothalamo-pituitary-adrenal axis mechanism. Further studies are needed to evaluate the potential of components of P. ginseng as an alternative treatment of depression, including clinical trial evaluation.

• Biomolecules & Therapeutics
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• v.26 no.4
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• pp.380-388
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• 2018

Neural stem cells (NSCs) have the ability to self-renew and differentiate into multiple nervous system cell types. During embryonic development, the concentrations of soluble biological molecules have a critical role in controlling cell proliferation, migration, differentiation and apoptosis. In an effort to find optimal culture conditions for the generation of desired cell types in vitro, we used a microfluidic chip-generated growth factor gradient system. In the current study, NSCs in the microfluidic device remained healthy during the entire period of cell culture, and proliferated and differentiated in response to the concentration gradient of growth factors (epithermal growth factor and basic fibroblast growth factor). We also showed that overexpression of ASCL1 in NSCs increased neuronal differentiation depending on the concentration gradient of growth factors generated in the microfluidic gradient chip. The microfluidic system allowed us to study concentration-dependent effects of growth factors within a single device, while a traditional system requires multiple independent cultures using fixed growth factor concentrations. Our study suggests that the microfluidic gradient-generating chip is a powerful tool for determining the optimal culture conditions.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.129-136
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• 2005

The deterministic analysis method has generally used to evaluate the slope stability and it evaluates the slope stability with decision value that is a representative value of design variables. However, one of disadvantages in the deterministic approach is there is not able to consider the uncertainty of soil strength properties, even though it is the biggest influential parameter of the slope stability. On the other hand, the limit state design(LSD) can take a consideration of uncertainties and computes both the reliability index and the probability of failure. LSD method is capable of overcoming the disadvantages of deterministic method and evaluating the slope stability more reliably. In this study, both the mean value and standard deviation of the internal land's representative soil strength properties applied to process the LSD method. The major purpose of this study is to gauge the general applicability of the limit state design in soil slope and to weigh the comparative validity of the proposed partial safety factor. In order to reach the aim of this study, the partial safety factor and resistance factor which totally satisfied the slope's overall safety factor were calculated by the load and resistance safety factor design (LRFD).

• Korean Journal of Occupational Health Nursing
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• v.13 no.2
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• pp.89-103
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• 2004

One of the major health problems of working women is job stress according to many studies. However, existing job stress questionnaires are suitable for men and men's job environments only, and do not reflect emotional labor for sales people. The aim of this research is to find women's job stress factors. The subjects of this investigation are married working women in sales since they experience emotional labor in addition to physical and psychological labor and the work-family conflict is very important job stressor for them. The job stressor of married sales women was analyzed through qualitative research. After I had in-depth interviews with 20 married sales women, I identified 49 new concepts, 3 main categories and 17 sub categories. The results are like the following. 1. 3 main categories are job factor, aggravate factor, and compensate factor. 2. Job factor has 5 sub-categories including 'increasing of selling', 'emotional labor' and 'physical burden'. 3. Aggrabate factor has 6 sub-categories including 'work/family conflict', 'relationship with higher office' and 'relationship with a fellow worker' 4. Compensate factor has 6 sub-categories including 'opportunity of employment', 'discrimination', and 'prestige' Consequently this study newly found some major job stressors for married working women in sales department.

• Research in Community and Public Health Nursing
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• v.12 no.1
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• pp.239-246
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• 2001

This paper attempts to identify the occupational stress-related factors among the workers at the manufacturing industry and to provide the basic data concerning development of stress management program focused on the manufacturing industry. The subjects exhibit significantly highest level of 'the characteristics of task and participation in decision making factor'. And the mean score of 'the avoid coping strategies' was higher than 'the control coping strategies'. The main factor that affected the occupational stress responses was 'the physio-environmental factor' and it was explained 15.6% out of the total variance of the stress responses. Also, it would be explained 29% out of the total variance of the stress responses with 'the characteristics of task/participation in decision making factor', sex, social support, and 'extra-organizational stressor'. In conclusion. For developing the stress management program in workplace, 'the physical environmental factor' and 'the characteristics of task and participation in decision making factor' should be considered. Also, It should be identified the direct and indirect paths among factors that significantly related factors to the occupational stress of workers further more.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.6
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• pp.74-79
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• 2002

This paper shows a reasonable design standard factor in commercial buildings, that was made by the systematic and statistical way considering actual conditions, such as investigated electric equipment capacity, electric power consumption, load characteristic, etc., for 23 commercial buildings. With a rapid growth of national economics with the development of intelligence society , electrical energy consumption markedly increased Expecially, it is increased electrical energy consumption in the commercial buildings and thus an energy conservation through efficient use of electricity became more important In our country, the estimation of demand factor and electric equipment capacity are not properly and thus the application of these factors are confusing and different in each electric design of the field.