• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.105-112
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• 2021

In the case of harbor structures, it is important to understand the characteristics of structures that are subjected to repeated loads as they are structures that receive repetitive loads such as wave pressure as well as static loads. In this study, the lateral resistance according to the pile embeded depth of the block breakwater reinforced with piles by cyclic lateral loads was obtained through an model experiment. As the depth of embedment of the pile increased, the lateral resistance showed a tendency to increase. As the load was repeated, the gradient of the lateral resistance gradually appeared to be gentle. The bending moment of the rear pile was larger than that of the front pile. The bending moment of piles in the ground was similar to that when the pile head was free in the cohesionless of Broms (1964).

• Journal of the Korea Fashion and Costume Design Association
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• v.24 no.1
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• pp.45-57
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• 2022

A rash guard, also known as rash vest or rashie, is functional sportswear that protects the wearer's skin from various dangers during outdoor sports activities. It is durable and comfortable since it is designed considering muscle movement. In modern society, more and more people enjoy leisure activities due to an increase in income level and increased leisure hours. Water leisure activities are increasingly enjoyed in the summer. As the way people think of leisure evolves, people are more inclined toward dynamic leisure sports rather than static facility tourism. Therefore, more research on rash guards is required. By identifying and analyzing the design preferences and purchase behaviors of young adults on rash guards, this study aims to provide basic data on the actual sportswear behaviors concerning those who are most active in water sports, people in their 20s and 30s. Furthermore, the study aims to contribute to a healthy exercise lifestyle for women who enjoy water sports and the growth of the water sportswear market. In the study, a survey was conducted using a questionnaire to investigate the wearing behaviors and purchase preferences as well as the wearing satisfaction on rash guards. For the study, 200 copies of the questionnaire were distributed and collected to be used as analysis data. The questionnaire consisted of 36 questions, 6 about demographic characteristics, 11 about purchase preferences, and 19 about wearing satisfaction. The collected data was analyzed using the statistical program SPSS 8.0. The study results can be used as basic data to investigate the design preferences and wearing behaviors of rash guards of women in their 20s and 30s. The results found numerous complaints on comfortableness and durability, which suggests more concern and improvements are necessary in those areas when designing patterns for rash guards.

• The Journal of the Korea Contents Association
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• v.22 no.1
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• pp.126-137
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• 2022

Whether an excellent animation film has vitality and charm largely depends on the aesthetic and emotional experience it brings to the audience, as well as the flexible use of the medium-long shot during the production of the animated film, especially the long take shot. It can then realize the real emotional communication between the animated film and the audience, stimulate the aesthetic experience, and achieve emotional resonance and sublimation. This thesis studies the characteristics and morphological divisions of moving long-shot composition and static composition and explores the diversified theories of animated emotional experience. Additionally, combined with the actual application analysis in the excellent animation feature "Prince Nezha's Triumph Against Dragon King", this thesis discussed the changes in the emotional experience created by the long take shots in the animation. This thesis finally summarized the relationship between the long shots in animation and the emotional experience of the animation creators, and how long shots stimulate viewers' aesthetic and emotional experience. In this way, it also provides a reference for future animation theory research, and finally creates animation works that bring high-quality emotional experience to the audience.

• Tribology and Lubricants
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• v.38 no.1
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• pp.27-31
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• 2022

Harmonic drives have attracted increasing attention with the development of materials, parts, and related equipment. Harmonic drives exhibit high deceleration, high accuracy, and light weight. The stiffness of flexible splines according to the radial load is studied using a commercial FEM program to design the structure of the flexible spline and finite element to improve the weight and price competitiveness of harmonic drives. In addition, several studies have measured and compared friction coefficients based on 3D printed tread patterns. However, owing to the characteristics of plastic materials, a decrease in stiffness in the radial direction is inevitable. To prevent a decrease in stiffness in the radial direction, we designed and manufactured flex splines with a wrinkle shape. Through structural analysis, the reaction force and stiffness in the radial direction were determined. In addition, the maximum angle of the mound was derived by theoretical calculations, and the performance of the harmonic drive was compared with the results obtained in the mound experiment. Structural analysis shows that the shape of wrinkles decreased the stress and reaction force and increased the safety factor in comparison with that of the circular shape. During performance verification through continuous experiments, the developed harmonic drive showed continuous performance similar to that of an actual tank model. It is expected that the flex spline with a compliant spring and wrinkle shape will prevent a decrease in the radial stiffness.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.5
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• pp.49-59
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• 2022

The SHAPE algorithm has the advantage of being able to shape the pulse spectrum as desired and design it not to distort other characteristics, so it was used in the active sonar pulse design. In this paper, we propose a pulse design using the SHAPE algorithm for a multi-static sonar system to reduce the cross-correlation between frequency-adjacent pulses and prevent the performance degradation of the pulses themselves. The boundary function of the SHAPE algorithm is set to be limited to the pulse bandwidth. As a result of applying the proposed design method to the sinusoidal frequency modulated pulse, the peak cross-correlation level (PCCL), which means the degree of cross-correlation, was reduced by 44.23 dB. Although the PCCL decreased by several tens of dB, no significant change in the ambiguity function was observed, and the integrated sidelobe level (ISL), which means the average value of the side lobe, increased by 11.64 dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1477-1482
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• 2022

Haze is a local weather phenomenon in which very small droplets float in the atmosphere, and the amount and characteristics of haze may vary depending on the region. In particular, these haze reduce visibility, which can cause air traffic interference and vehicle traffic accidents, and degrade the quality of security CCTVs and so on. Therefore, in the past 10 years, research on haze removal has been actively conducted to reduce damage caused by haze. In this study, local haze removal is performed by weight generation using a haziness degree evaluator to adaptively respond to haze-free, homogeneous haze, and non-homogeneous haze cases. And the proposed method improves the limitations of the existing static haze removal method, which assumes that there is haze in the input image and removes the haze. We also demonstrate the superiority of the proposed method through quantitative and qualitative performance evaluations with benchmark algorithms.

• Transactions of Materials Processing
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• v.31 no.5
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• pp.253-260
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• 2022

In this study, the microstructural characteristics of a high-speed-extruded Mg-5Bi-3Al (BA53) alloy and its tensile, compressive, and high-cycle fatigue properties are investigated. The BA53 alloy is successfully extruded at a die-exit speed of 16.6 m/min without any hot cracking using a large-scale extruder for mass production. The homogenized BA53 billet has a large grain size of ~900 ㎛ and it contains fine and coarse Mg₃Bi₂ particles. The extruded BA53 alloy has a fully recrystallized microstructure with an average grain size of 33.8 ㎛ owing to the occurrence of complete dynamic recrystallization during high-speed extrusion. In addition, the extruded BA53 alloy contains numerous fine lath-type Mg₃Bi₂ particles, which are formed through static precipitation during air cooling after exiting the extrusion die. The extruded BA53 alloy has a high tensile yield strength of 175.1 MPa and ultimate tensile strength of 244.4 MPa, which are mainly attributed to the relative fine grain size and numerous fine particles. The compressive yield strength (93.4 MPa) of the extruded BA53 alloy is lower than its tensile yield strength, resulting in a tension-compression yield asymmetry of 0.53. High-cycle fatigue test results reveal that the extruded BA53 alloy has a fatigue strength of 110 MPa and fatigue cracks initiate at the surface of fatigue test specimens, indicating that the Mg₃Bi₂ particles do not act as fatigue crack initiation sites. Furthermore, the extruded BA53 alloy exhibits a higher fatigue ratio of 0.45 than other commercial extruded Mg-Al-Zn-based alloys.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.6
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• pp.775-786
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• 2022

In the plant structures including nuclear power plants, penetrations are frequently installed in walls and slabs to reinforce facilities during operation, and reinforcing bars are sometimes cut off during concrete coring. Since these penetrations are not considered at the design or construction stage, cutting of reinforcing bar during opening installation is actually damage to the structure, structural integrity evaluation considering the stress transition range or effective width around the new penetration is necessary. In this study, various nonlinear analyses and static loading experiments are performed to evaluate the effect of reinforcing bar cutting that occurs when a penetration is newly installed in the shear wall of wall-type building of operating nuclear power plant. In addition, the decrease in wall stiffness due to the installed new penetration and cutting of reinforcing bars is evaluated and the stress and strain distributions of rebars around penetration are also measured.

• Structural Engineering and Mechanics
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• v.85 no.2
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• pp.179-195
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• 2023

The performance of reinforced concrete (RC) beam specimens strengthened using a newly proposed Side Near Surface Mounted (S-NSM) technology was investigated experimentally in this work. In addition, analytical and nonlinear finite element (FE) modeling was exploited to forecast the performance of RC members reinforced with S-NSM utilizing steel bars. Five (one control and four strengthened) RC beams were evaluated for flexural performance under static loading conditions employing four-point bending loads. Experimental variables comprise different S-NSM reinforcement ratios. The constitutive models were applied for simulating the non-linear material characteristics of used concrete, major, and strengthening reinforcements. The failure load and mode, yield and ultimate strengths, deflection, strain, cracking behavior as well as ductility of the beams were evaluated and discussed. To cope with the flexural behavior of the tested beams, a 3D non-linear FE model was simulated. In parametric investigations, the influence of S-NSM reinforcement, the efficacy of the S-NSM procedure, and the structural response ductility are examined. The experimental, numerical, and analytical outcomes show good agreement. The results revealed a significant increase in yield and ultimate strengths as well as improved failure modes.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.3
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• pp.10-21
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• 2022

The propellant tank, which is a space launch vehicle structure, must have structural integrity as various static and dynamic loads are applied during ground transportation, launch standby, take-off and flight processes. Because of these characteristics, the propellant tank cylinder, the structural object of this study, has a thin thickness, so buckling due to compressive load is considered important in the cylinder design. However, the existing buckling design standards such as NASA and Europe are fairly conservative and do not reflect the latest design and manufacturing technologies. In this study, nonlinear buckling analysis is performed using various analysis models that reflect initial defects, and a method for establishing new buckling design standards for cylinder structures is presented. In conclusion, it was confirmed that an effective lightweight design of the cylinder structure for common bulkhead propulsion tank could be realized.