• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.8
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• pp.541-548
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• 2019

In this paper, the required amount of heat for an anti-icing system of a Flush Air Data Sensing(FADS) system is predicted. For an efficient prediction during the early stage of a design process, a handbook method is used. A program of which inputs are flight conditions is developed to predict the required amount of heat. A CFD analysis is conducted to compute the water catch efficiency which is one of the core parameters used in the handbook method. Kriging method, one of well-known regression mothods, is utilized to construct a surface contour database to evaluate impingements of droplets. To predict the trajectories of droplets, the database of a flow field around the surface is built using Kriging method as well.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.5
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• pp.37-47
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• 2019

The study purposed to investigate the optimal location of core and offset outrigger system considering floor diaphragm. To accomplish this aim, a structure design of 70 stories building was performed by using MIDAS-Gen. And the leading factors of the analysis research were the slab stiffness, the stiffness of shear wall and the outrigger position in plan. Based on the analysis results, we analyzed and studied the influences of the shear wall stiffness and the slab stiffness on optimal location of core and offset outrigger considering floor diaphragm. The results of the analysis study indicated whether the slab stiffness, the stiffness of shear wall and the outrigger position in plan had an any impact on optimal location in outrigger system of tall building. Also the paper results can give help in getting the structural engineering materials for looking for the optimal position of outrigger system in the high-rise building.

• Journal of Navigation and Port Research
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• v.43 no.3
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• pp.197-208
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• 2019

This paper assessed the impacts of the specification of the yard, handling equipment, and operation approaches on the expected number of re-handles during the loading operation for empty containers. When the various types of empty containers from multiple shipping liners are placed in separate spaces from each other, then the storage space cannot be fully utilized. So as to increase the utilization of the storage space, empty containers from multiple vessel liners are stored together incurring additional re-handles during the loading operation. Several formulas are derived for the estimation of the expected number of handles, including re-handles, for empty container retrieval from a bay. Transfer cranes and top handlers are utilized as handling equipment and various retrieval strategies are examined. Numerical analysis was conducted to assess the effects of various designs and operational parameters of the container stacking yard on the expected number of handles.

• Journal of Digital Convergence
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• v.17 no.9
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• pp.291-299
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• 2019

This study is a nonequivalent control group pretest-posttest designed to understand the effect of ethical dilemma discussion program on human rights sensitivity and ethical values of university students. By providing ethical dilemma discussion program to university students in C university, G-do, the effectiveness was verified. Analyzed using IBM SPSS 24.0. The normality of the variables was verified by Shapiro-Wilk test. Homogeneity was verified using real number and percentage, Fisher's exact probability test and independent t-test. The program's effect was verified using paired t-test. The results of this study are as follows: after the ethical dilemma discussion program, the experimental group's human rights sensitivity(t=-2.32, p=.025), and ethical value(t=-2.43, p=.020) were higher than the control group. Therefore, the ethical dilemma discussion program of this study helped improve the human rights susceptibility and ethical values of the subjects. Further research is needed to verify the effects of ethics education on diverse groups.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.4
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• pp.233-240
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• 2019

Open-hole tensile tests are usually performed to measure the tensile strengths of composites as they are an essential parameter for designing composite structures. However, correctly modeling the tensile test is extremely challenging as it involves various damages such as fiber and matrix damage, delamination, and debonding damage between the fiber and matrix. Therefore, a progressive damage model was developed in this study to estimate the in-plane failure and delamination between the fiber and matrix. The Hashin damage model and cohesive zone approach were used to model ply and delamination failures. The results of the present model were compared with previously published experimental and numerical findings. It was observed that neglecting delamination during finite element analysis led to overestimation of tensile strength.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.38-39
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• 2019

Optimal route planning is the route planning to minimize voyage time or fuel consumption in a given ocean environment. Unlike the previous studies on weather routing, this study proposes an optimization method for the route planning to avoid the grounding risk in the coast. The route way-points were searched using Dijkstra algorithm, and then the optimization was performed to minimize fuel consumption by setting the optimization design parameter to the engine rpm. To set the engine rpm, a method to use the fixed rpm from the departure point to the destination point, and a method to use the rpm for each section by dividing the route were used. The ocean environmental factors considered for route planning were wind, wave, and current, and the depth information was utilized to compute grounding risk. The proposed method was applied to the ship passing between Mokpo and Jeju, and then it was confirmed that fuel consumption was reduced by comparing the optimum route and the past navigated route.

• Journal of the Korean Geotechnical Society
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• v.35 no.2
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• pp.5-17
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• 2019

Dynamic centrifuge model test was conducted to evaluate the dynamic stability of the pile-supported slab track method during dynamic railway loading and earthquake loading. The centrifuge tests were carried out for various condition of embankment height and soft ground depth. Based on test results, we found that the bending moment was increased with embankment height and decreased with soft ground depth. In addition, it was confirmed that the pile-supported slab track system could have dynamic stability for short-period seismic loading. However, in case of long-period seismic loading, such as Hachinohe earthquake, the observed maximum bending moment reached to pile cracking moment at the return period of 2,400 year earthquake. The criterion of ratio between embankment height and soft ground depth was suggested for dynamic stability of pile-supported slab track system.

• Fire Science and Engineering
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• v.33 no.1
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• pp.99-104
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• 2019

In a gas system fire extinguishing system, extinguishing agents are usually stored with approximately 280 bar at $21^{\circ}C$ and are released at approximately 8 MPa through the decompression valve and orifice to quickly suppress the fire. When extinguishing agents are discharged, they cause a loud noise (approximately 140 dB), which can damage electronics, such as hard disk drives (HDDs). Therefore, the noise is becoming a serious issue in the gas extinguishing system. The method of the noise reduction by adding an absorbent is most general and in this study, the thickness of the absorbent was as a selected design variable. The noise level at the observation point and the flow characteristics inside the nozzle were numerically calculated and analyzed using the commercial code ANSYS CFX ver. 18.1.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.7-13
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• 2018

The strength of concrete is affected significantly not only by the internal influence factors of cement, water, sand, aggregate, and admixture, but also by the external influence factors of concrete placement delay and curing temperature. The objective of this research was to predict the concrete strength considering both the internal and external influence factors when concrete is placed at the construction site. In this study, a concrete strength test was conducted on the 24 combinations of internal and external influence factors, and a neural network model was constructed using the test data. This neural network model can predict the concrete strength considering the external influence factors of the concrete placement delay and curing temperature when concrete is placed at the construction site. Contractors can use the concrete strength prediction neural network model to make concrete more robust to external influence factors during concrete placement at a construction site.

• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.327-336
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• 2021

This study aimed to examine the online lecture quality, self-leadership, and degree of academic self-efficacy of nursing students who experienced online lecture and to identify the factors that influence academic self-efficacy. The subject of this study was 115 nursing students at one university, and the study design is a descriptive survey study that collected data through a structured questionnaire. As a result of this study, self-leadership(β =.431, p=<.001) and online class environment(β =.314, p=.004), a sub-factor of online lecture quality, were significant influencing factors on the academic self-efficacy of nursing college students. These variables explained 37.7% of the total variance in academic self-efficacy. Based on the results of this study, it is expected that it will be used as basic data for cultivating self-leadership and improving the online class environment in order to improve the academic self-efficacy of nursing students taking online classes.