• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.1
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• pp.53-63
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• 2006

The objective of this study is to analyze the smoke movement and the smoke extraction efficiency using by the partial extraction system for case of tunnel fire. Based on Froude modeling and isothermal model, the 1/20 scaled model tunnel (12m long) was constructed. In the case of the upper critical velocity in the main tunnel, the smoke extraction efficiency shows almost same between group damper and distributed damper. Finally, if the fire occurs on a traffic Jam in a tunnel, it is proposed that the open dampers in partial gallery extract smoke from the main tunnel without jet fan operation. Then, after the passengers have escaped the tunnel, the jet fans work on. On the other hand, If the traffic is uncongested in the tunnel, the jet fans (smoke control system) and partial extraction system (smoke exhaust system) are operated at once in tunnel fire.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.9
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• pp.855-862
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• 2013

A series of 1/5 scale-down reactor flow distribution tests had been conducted to determine the hydraulic characteristics of an APR+ (Advanced Power Reactor Plus), which were used as the input data for an open core thermal margin analysis code. In this study, to examine the applicability of computational fluid dynamics with the porous model to the analysis of APR+ internal flow, simulations were conducted using the commercial multi-purpose computational fluid dynamics software ANSYS CFX V.14. It was concluded that the porous domain approach for some reactor internal structures could adequately predict the flow characteristics inside a reactor in a qualitative manner. If sufficient computational resources are available, the predicted core inlet flow distribution is expected to be more accurate by considering the real geometry of the internal structures, especially upstream of the core inlet.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.3
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• pp.210-217
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• 2011

Evolution of tip vortex generated by a model rotor blade which has a symmetric blade section has been investigated by use of the laser doppler anemometry. Swirl and axial velocity components of tip vortex were measured by the phase averaging technique within one revolution of a rotor blade. It was found that tip vortex becomes matured until 27 degrees and diffuses afterwards with diffusing rate becoming slower compared to the case of the asymmetric blade section, but the tip loss was expected to become more substantial. Swirl velocity components were well fit to n=2 model of Vatistas within measured wake ages, showing the self-similarity exists for the swirl velocity components. The axial components were followed with Gaussian profiles, but had much higher peak values than those of the symmetric blade section.

• Korean Journal of Social Welfare
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• v.58 no.2
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• pp.87-118
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• 2006

The purpose of this paper is to test construct validity of contextual performance of social worker. The participants in this study included 170 social worker in community welfare center nationwide. A narrative data of social work practice experience and MTMM(multitriat-multimethod) data on job performance were collected. I classified meaningful contextual behavior cases by qualitative methods, and examined discriminant validity of contextual and task performance by CFA model. Data analysis showed that social workers' contextual performance has discriminant validity and sub constructs of this concept have internal consistency. However, some construct are not completely independent.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.229-234
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• 2005

This study was carried out to analyze the effect of wind load on the stability of a 50ton container crane using wind tunnel test and provide a container crane designer with data which can be used in a wind resistance design of a container crane assuming that a wind load at 75m/s wind velocity is applied on a container crane. Data acquisition conditions for this experiment were established in accordance with the similarity. The scale of a container crane dimension, wind velocity and time were chosen as 1/200, 1/13.3 and 1/15. And this experiment was implemented in an Effect type atmospheric boundary-layer wind tunnel with $11.52m^2$ cross-section area. Each directional drag and overturning moment coefficients were investigated and uplift forces at each supporting point due to the wind load were analyzed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.311-316
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• 2006

This study was carried out to analyze the effect of wind load on the structural stability of a container crane according to the change of the boom shape using wind tunnel test and provided a container crane designer with data which can be used in a wind resistance design of a container crane assuming that a wind load at 75m/s wind velocity is applied on a container crane. Data acquisition conditions for this experiment were established in accordance with the similarity. The scale of a container crane dimension, wind velocity and time were chosen as 1/200, 1/13.3 and 1/15. And this experiment was implemented in an Eiffel type atmospheric boundary-layer wind tunnel with $11.25m^2$ cross-section area. Each directional drag and overturning moment coefficients were investigated and uplift forces at each supporting point due to the wind load were analyzed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.625-631
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• 2021

This study examined the effects of self-critical perfectionism on organizational citizenship behavior (OCB) and the moderating effects of gender in the relationship to understand deeply the dilemmatic situation resulting from OCB at the individual level. In other words, based on the conservation of resources theory, this study examined how self-critical perfectionism influences the OCB and how gender moderates the relationship between self-critical perfectionism and OCB. More specifically, this study predicts that self-perfectionism will be negatively related to OCB. Furthermore, this negative relationship between self-critical perfectionism and OCB will be strengthened in men compared to women. To test these hypotheses, the supervisor-subordinate survey was conducted, and 150 dyad data were analyzed. The analytical results of HLM (Hierarchical Linear Modeling) showed that self-critical perfectionism negatively influenced the OCB, and this negative effect was strengthened in men compared to women. This paper suggests implications and limitations for the literature on OCB.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.463-476
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• 2021

This study examined significant differences in the impact of workplace bullying on emotional depletion and organizational commitment, and used 400 questionnaires to examine whether there would be significant differences depending on social support. As an analysis method, we used SPSS 24 for sample characteristics, SmartPLS 3 statistical programs for verifiable factor analysis, reliability and validity, path analysis, and structural equation models. Studies have shown that bullying in the workplace affects significant positive (+) for emotional depletion, and that emotional depletion affects significant negative (-) for tissue commitment. The influence relationship between workplace bullying and tissue commitment was partially mediated in the direction of wealth (-), and the effect of emotional depletion on tissue immersion was shown to be significant differences in the control of social support. Implications are that bullying in the workplace affects emotional depletion, so corporate efforts to prevent bullying are urgently needed, suggesting that employees can improve their organizational commitment, by using a system or community that can promote communication with their bosses.

• Journal of the Korean GEO-environmental Society
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• v.24 no.5
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• pp.13-20
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• 2023

The Gangneung region has an environment suitable for the formation of organic soil, and there is an alluvial layer in which sedimentary sand layers are distributed on the upper and lower parts of the organic soil. In order to evaluate the seismic safety of the railway roadbed passing through the Gangneung area, a railway roadbed and ground model considering the similarity ratio was fabricated, a shaking table test was conducted, and the seismic stability was evaluated by comparing the effective stress analysis results. The applied seismic waves were artificial seismic waves, Gyeongju seismic waves, Borah seismic waves, Nahanni seismic waves, and Tabas seismic waves. It became. Due to the ground reinforcement effect by jet grouting applied to the lower ground of the new roadbed, the displacement of the new roadbed was found to be reduced from a minimum of 33.7% to a maximum of 56.7% compared to the existing roadbed. The shaking table test results were verified by effective stress analysis using the Finn model of the Flac program, and showed a similar trend to the shaking table test values.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.2
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• pp.157-167
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• 2008

The aeration of an overtopping wave on a vertical structure generated by a plunging wave was investigated through laboratory measurements of void fraction. The overtopping wave occurring after wave breaking becomes multi-phased and turbulent with significant aeration, so that the void fraction of the flow is of importance. In this study, fiber optic reflectometer and bubble image velocimetry were employed to measure the void fraction, velocity, and layer thickness of the overtopping flow. Mean properties were obtained by ensembleand time-averaging the repeated instantaneous void fractions and velocities. The mean void fractions show that the overtopping wave is very high-aerated near the overtopping wave front and relatively low-aerated near the deck surface and rear free surface of the wave. The flow rate and momentum of the overtopping flow estimated using the measured data show that the void ratio is an important parameter to consider in the multiphase flow. From the similarity profiles of the depth-averaged void fraction, velocity, and layer thickness, one-dimensional empirical equations were obtained and used to estimate the flow rate and momentum of the overtopping flow.