• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.4
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• pp.362-370
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• 2008

In this paper, we propose a 2D-FE model in single impact with combined physical factors to obtain a unique residual stress by shot peening. Applied physical parameters consist of elastic-plastic deformation of shot ball, material damping coefficients, strain rate, dynamic friction coefficients. As a kinematical parameter, there is impact velocity. Single impact FE model consists of 2D axisymmetric elements. The FE model with combined factors showed converged and unique distributions of surface stress, maximum compressive residual stress and deformation depth. Further, in contrast to the FE models with rigid shot and elastic deformable shot, FE model with plastic deformable shot produces residual stresses very close to experimental solutions by X-ray diffraction. We therefore validated the 2D FE model with combined peening factors and plastic deformable shot. This FE model will be a base of the 3D FE model for residual stresses by multi-impact shot peening.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.275-278
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• 2005

In this study, the dynamic properties of a floor impact sound isolation pad expressed in terms of the natural frequency, the dynamic stiffness per unit area and the loss factor are measured by the resonant method. By using the measured dynamic properties, the vibration transmissibility diagram is obtained for each isolation pad, which is compared with the values tested by the impact sound sources at the room in an apartment. From the comparative results, it is found that the noise reduction Performances. of isolation pads are closely connected with the natural frequency and the dynamic stiffness per unit area.

• Journal of Environmental Impact Assessment
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• v.6 no.1
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• pp.47-54
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• 1997

Vegetation Index(VI) derived from remote sensing data is used to assess ecosystem factor in Environmental Impact Assessment(EIA) process. Ecosystem factor has been prepared by Degree of Green Naturality(DGN) mainly in Environmental Impact Statements. But DGN has room for improvement of assessing actual ecosystem situation. The objectives of this study are to define the relationship between field measure DGN and VI, and to develop methodologies to use VI for assessing the status and conditions of natural ecosystem. For verification of DGN and VI, 35 sites using global positioning system are selected and reviewed. Correlation coefficients of DGN and VI shows highly as 0.69. Also VI in EIA found it can be applied to assess ecosystem. It concluded that VI as well as DGN can be applied to assess ecosystem newly and largescale.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.1
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• pp.85-95
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• 2015

A responsibility of superior management in an airline has become enormous due to rapid increase of airline's organization and its network. Even though a leadership of superior management is believed to be an important factor, it is almost impossible for management to be responsible for all the areas of an airline organization. This is why leadership should be go down to working level people. Self-leadership means that working level people possess leadership, delegated by their superior persons, and improve their work environment with the leadership as well as related right and responsibility. This paper has tried to find out the components of self-leadership perceived by foreign cabin crews and analyzed the impact of self leadership into airline's organizational effectiveness. Based on empirical research results, this paper would suggest administrative and operational implications of managing foreign cabin crews in K-airline. It was found out foreign cabin crews perceive that self reward and self evaluation have a positive impact on self observation factor. The self observation factor has a significant effect on self goal. The self goal is analyzed as a major factor which results in organizational effectiveness.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.4
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• pp.192-199
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• 2004

Elastic-factor of elastic epoxy were investigated by TMA (Thermomechanical Analysis), DMTA (Dynamic Mechanical Thermal Analysis), TGA (Thermogravimetric Analysis) and FESEM (Field Emission Scanning Electron Microscope) for structure-images analysis as toughness-investigation to improve brittleness of existing epoxy resin. A range of measurement temperature of the TMA and DMTA was changed from -20($^{\circ}C$) to $200^{\circ}(C)$, and TGA was changed from $0^{\circ}(C)$ to $600^{\circ}(C)$. Glass transition temperature (Tg) of elastic epoxy was measured through thermal analysis devices with the content of 0(phr), 20(phr) and 35(phr). Also, thermal expansion coefficient (a), high temperature, modulus and loss factor were investigated through TMA, TGA, and DMTA. In addition, the structure of specimens was analyzed through FESEM, and then elastic-factor of elastic epoxy was visually showed by FESEM. As thermal analysis results, 20(phr) was more excellent than 30(phr) thermally and mechanically. Specially, thermal expansion coefficient, high temperature, modulus, and damping properties were excellent. By structure-images analysis through FESEM, we found elastic-factor of elastic epoxy that is not existing epoxy, and proved high impact.

• Asia-Pacific Journal of Business
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• v.12 no.1
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• pp.121-134
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• 2021

Purpose - This study examines whether flight-to-liquidity (FTL) explains the dynamic liquidity risk on stock returns, and whether it has a significant influence on determinants the cross-section of stock returns. Design/methodology/approach - This study suggests a new risk factor, dynamic liquidity hedge portfolio (DLP), to reflect the dynamic impact of liquidity risk on stock returns and the Fama-MacBeth 2 stage regression analysis is employed in order to analyze the data. Findings - First, the DLP factor shows more positive and significant beta for the small or illiquidity stocks. Second, the DLP shows a different influence than SMB (size risk factor), HML (value risk factor), NMP (liquidity risk factor), FTVOL (total volatility factor) in determining the cross-section of stock returns. In addition, the DLP has a statistically significant risk premium of around 5%, which is relatively larger than other risk factors. Research implications or Originality - This study has academic value in terms of newly confirming that the DLP factor has a more significant impact on cross-sectional determination of stock returns than other risk factors by proposing a conditional liquidity factor that can explain the FTL phenomenon.

• Magazine of the Korea Concrete Institute
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• v.7 no.1
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• pp.109-116
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• 1995

In tnis study, the impact factors of a simply supported highway bridge due to a vehicle moving across the span are presented. This variable has received cons~derable attention in recent years, both analytically and experimentally. The KBDC specification equation has a maximum 30 percent value which decreases with span length. The results of field tests showed that the dynamic load effects are mostly lower t.hari present KBDC value and that the impact factor does not vary significantly with spar1 as implied in KHUC. The rnain parameters affecting lmpact are the br dge approach. bumps, and other pavement roughness. In thls study, based on test results, three values of impact factors are provided by correlating the roughness of the surface to the deck condition survey values. The present study proposes reasonable impact factors for the strength evaluation of highway bridges. This study may be extended to the evaluation of existing brdges.

• Korean Journal of Construction Engineering and Management
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• v.14 no.2
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• pp.56-64
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• 2013

New construction technologies, especially automated equipment, are rarely deployed on a construction site where many accidents and claims occur. This study analyzed and derived impact factors for technology adoption to improve the chance of adopting automated construction equipment to the field. First, impact factors were classified into functional and non-functional factors. Then the functional factors were divided into usability and functionality factors, and the non-functional factors into cost, construction property, and organization factors. Next, the importance and realization possibility of each impact factor were analyzed through a survey with experts. Usability and functionality were analyzed to have the highest importance and realization possibility. Lastly, the differences between construction companies and equipment development companies in the importance and realization possibility of each factor were analyzed. Construction companies recognized previous relationship, operator's attitude, members' will, and construction quality more important than equipment development companies.. The equipment development companies should consider these differences between the view of construction companies and that of equipment development companies on the impact factors. The result of this study can be used as a basis for evaluating for automated construction equipment in the preliminary development phase.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.319-326
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• 2000

It is investigated character of the dynamic behavior at over excavation zone of roadbed using crushed stone instead of lean concrete. It is considered that behavior of roadbed using PENTAGON-3D and Baber's equation. Typical load of sine wave type using impact factor is compared to moving load system to examine relationship in using PENTAGON-3D case. Variations of this paper are material properties of roadbed, train velocity, subgrade bearing capacity. Using variations, safety of roadbed is estimated by dynamic behavior character.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.12 no.2
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• pp.29-42
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• 2004

This paper performs a historical review on aviation threats through a statistical survey. The impact factor, as a criterion to measure the seriousness of the threats occurred, is introduced and evaluated based on annual totals of hijacking and fatalities against aircraft 1948 through 2004. Also, the paper suggests processes of evaluating the level of threats and key functions for an effective management of the aviation security.