• Journal of Korean Society of Steel Construction
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• v.26 no.1
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• pp.43-53
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• 2014

A single plate connection(SPC) consists of a plate welded to the columns and bolts connected to the beam web. The SPC is widely used for a simple shear connection of steel structure because it is easy-to-fabricated, easy-to-installed and economical. The conventional SPC is used for 2 to 12 bolts in a single vertical row. It is designed to limit the plate thickness by bolt diameter to obtain flexible and ductile connections. The design strength for eccentric shear shall be the lesser of the shear strength of bolts or bearing strength of plate and when the design strength is decided by edge distance failure, the results can be very conservative. Although the research on special solution for 'weak-plate/strong-bolt' model with 2 to 4 bolts has been conducted by L. S. Muir, and W. A. Thonton, 2004, study on generalized design procedures did not conduct. This study proposed design procedure for evaluation of the design strength of eccentric shear bolt groups on a single plate connection based on the actual edge distance and the direction of bolt reaction forces by using elastic vector method(EVM) and instantaneous center of rotation method(ICM).

• Journal of Korean Society of Steel Construction
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• v.19 no.2
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• pp.161-170
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• 2007

In this study, to improve on the inaccurate results of the orthotropic plate analysis, we aim to propose a modified coefficient of the orthotropic flexural rigidity for stiffened plates with rectangular ribs considering the dimensions of ribs. The sensitivity of the flexural rigidity and the maximum displacement according to the dimensions of stiffened plates were analyzed and the parametric study on the modified coefficient of the orthotropic flexural rigidity of stiffened plates was performed. The results show that the ratio of modified coefficients can be expressed as a function for each rib height, space and thickness regardless of plate thickness and the modified flexural rigidity can be easily estimated from the ratio functions of modified coefficients. The application of the coefficient function to various types of stiffened plates with different boundary conditions, aspect ratios, rib arrangement and loading size shows that the proposed function improves the accuracy of the orthotropic plate analysis compared with the results of the reference. Therefore, the orthotropic plate analysis of stiffened plates with rectangular ribs can easily achieve more accurate results using the coefficient function proposed in this study.

• Journal of Korea Water Resources Association
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• v.40 no.2 s.175
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• pp.171-182
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• 2007

In this study, as a method for decreasing the confidence interval of the estimates of Clark hydrograph's concentration time and storage coefficient, regression equations of these parameters with respect to those of rainfall, meteorology, and basin characteristics are derived and analyzed using the Monte Carlo simulation technique. The results are also reviewed by comparing them with those derived by applying the Bootstrap technique and empirical equations. Results derived from this research are summarized as follows. (1) Even in case of limited rainfall events are available, it is possible to estimate the mean runoff characteristics by considering the affecting factors to runoff characteristics. (2) It is also possible to use the Monte Carlo simulation technique for estimating and evaluating the confidence intervals for concentration time and storage coefficient. The confidence intervals estimated in this study were found much narrower than those of Yoo et al. (2006). (3) A supporting result could also be derived using the Bootstrap technique. However, at least 20 independent rainfall events are necessary to get a rather significant result for concentration time and storage coefficient. (4) No empirical equations are found to be properly applicable for the study basin. However, empirical equations like the Kraven(I) and Kraven(II) are found valid for the estimation of concentration time, on the other hand the Linsley is found valid for the storage coefficient In this study basin. But users of these empirical formula should be careful as these also provide a wide range of possible values.

• Journal of the Mineralogical Society of Korea
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• v.18 no.1
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• pp.1-9
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• 2005

The electrocatalytic reduction of O₂ was investigated with methyl viologen and methylene blue incorporated clay-modified electrodes. Clay suspensions were prepared with Na-montmorillonite, Ca-montmorillonite, and kaolinite. The methyl viologen-clay modified electrodes were made by coating clay suspensions adsorbing methyl viologen on a glassy carbon electrode. Cyclic voltammetry were performed in aqueous media to investigate the electrocatalytic property of the modified electrode in reducing O₂. A Na-montmorillonite modified electrode showed the greatest adsorption capacity for methyl viologen. The modified electrode made of Na-montmorillonite suspension of 0.87 g/10 mL and a 2.5 mM of methyl viologen solution showed the most effective electrocatalytic property, where the catalytic reduction potential was shifted by 242.6 mV toward the positive potential. The electrocatalytic ability was more significant in acidic (pH=3.7) and alkaline (pH=12.7) media than the neutral pH range (6.3∼8.3). The methyl viologen-Na-montmorillonite modified electrode had the good reproducibility and maintain the electrocatalytic property over 20 times reuse.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.319-323
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• 1996

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• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.351-356
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• 1996

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• 한국해양학회지
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• v.22 no.2
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• pp.105-118
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• 1987

A series of anchor stations were occupied along the Keum EAstuary during six different periods of tidal and fluvial regimes. The results clearly show that the formation and evolution of the turbidity maximum play an important role in the sedimentary processes in this environment. The turbidity maximum in the Keum Estuary is primarily related to the tidal range at the mouth and is caused by the resuspension of bottom sediments. In this estuary, the turbidity maximum is not a permanent feature and shows semidiurnal, fortnightly and seasonal variations. Repetition of deposition and resuspension of fine sediments occur in response to the variation in current velocity associated with semidiurnal tidal cycles. The core of turbidity maximum shifts landward or seaward accordion to the flood-ebb succession. The turbidity maximum also shows a fortnightly variation in response to the spring-neap cycles. Thus, the turbidity maximum degenerates during neap-tide and regenerates during spring-tide. The freshwater discharge is also an important factor in the formation and destruction of the turbidity maximum. The increase in freshwater discharge in rainy season can create an ebb-dominant current pattern which enhances the seaward transport of suspended sediments, resulting in the shortening of residence time of suspended materials in the estuary. Thus, under this high discharge condition, the turbidity maximum exists only during spring-tide and starts to disappear as the tidal amplitude decreases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.102-111
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• 2016

This study aims to identify the characteristics of the regional innovation system(RIS) and the determinants of innovation performance of SMEs. Data were collected from a questionnaire survey on 64 SMEs in the Daejeon and Chungcheong regions to uncover the relationship between capabilities, regional innovation capacities and innovation performance. The moderating effects of regional innovation capacities on the relationship between firms' innovation capabilities and performance were also tested. Empirical results revealed that R&D, marketing and entrepreneurial orientation had positive effects. The moderating effect of regional innovation capabilities on the relationship between entrepreneurial orientation (risk taking) and performance was also confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.449-458
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• 2017

This research is a descriptive correlation research for comprehending the end of life care stresses, work environment, and reduction of nurses in geriatric hospitals and analyzing the factors influencing their burnout. We recruited 195 nurses from 8 geriatric hospitals in B metropolitan city and collected data on the end of life care stress, work environment and reduction using organized questionnaires. The data were analyzed with SPSS WIN 21.0 program. The average grade of end life care stress was $3.84{\pm}0.56$, nursing work environment $3.25{\pm}0.60$, and burnout $2.93{\pm}0.52$. There was a positive correlation between the end of life care stress and reduction(r=.206, p=.004) but a negative correlation between nursing work environment and reduction(r=-.431, p<.001). The most influential factor on the reduction was nursing satisfaction(${\beta}=-.302$), followed by work environment(${\beta}=-.294$), age(${\beta}=.286$), duty style(${\beta}=-.17$), and end of life care stress(${\beta}=.164$). The overall explanatory power was 41.2%.These results suggest that in order to minimize the reduction of nurses in geriatric hospitals, the provision of a supportive work environment which enhances their pride and responsibility as a nurse and offers incentives is required with effective distribution of duties, development of the end of life nursing education and administrative tools for reducing their stress.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.458-470
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• 2016

The purpose of this study was to understand and describe nurses' recognition regarding successful aging of hospitalized elderly in long-term care hospitals. Data were collected using focus group interviews in 2016. Three focus group interviews were held in three long-term care hospitals, and a total of 14 nurses participated. All interviews were recorded and transcribed as they were spoken, and data were analyzed using qualitative content analysis. A total of 25 concepts were identified, 15 subcategories, and five major categories emerged from the analysis. The five categories of the nurses' recognition about successful aging of hospitalized elderly in long-term care hospitals were "adjusting themselves to a lifestyle of long-term care hospital," "living positively in each situation," "communicating with each other and making a relationship," "obtaining interest and support of their families," and "maintaining economic independence". Therefore, further qualitative study will be performed and compared with this study results on successful aging of hospitalized elderly in long-term care hospitals. Moreover, based on these study results, it is necessary to develop and apply programs for successful aging of hospitalized elderly in long-term care hospitals.