• Journal of Fisheries and Marine Sciences Education
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• v.28 no.4
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• pp.893-902
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• 2016

The purpose of this study is to investigate the effect of wearing a weightlifting belt, which is an auxiliary equipment used during squat, by measuring and analyzing biomechanical difference in lower limb and proposing safer and to suggest a more effective exercise method for general population. Selected 8 male participants in their 20s who have not performed regular resistance exercise for at least a year, but have experience of performing squat. The comprehensive method of study is as follows: subjects were notified of the purpose of the study and were told to practice warm-up and the squat motion for the experiment for 20 minutes. When the participant believed they were ready to begin, the experiment was started. At controlled points, foot pressure distribution sensor has been installed. Then left and right feet have been placed on the pressure distribution sensor, from which data for successful squat position that does not satisfy the criteria for failure have been collected and computed with Kwon3D XP program and TPScan program. For data processing of this study, SPSS 21.0 was used to calculated mean (M) and standard deviation (SD) of the analyzed values, and paired t-test has been conducted to investigate the difference before and after wearing the weightlifting belt, with p-value of ${\alpha}<.05$. As for time consumed depending on usage of weightlifting belt in squat, statistically significant difference has been found in P2, which is recovery movement. Lower limb angle depending on usage of weightlifting belt in squat has shown statistically significant difference in E1 foot joint(p<. 001). There has been statistically significant difference in E2 knee joint. Foot pressure percentage depending on usage of weightlifting belt in squat were found to be statistically significant (p<. 01) in both regions of anterior and posterior foot.

• Journal of Welding and Joining
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• v.27 no.5
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• pp.55-61
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• 2009

Pure titanium and its alloys have good formability, excellent corrosion resistance and high strength to weight ratios. Therefore, it has been using to heat exchangers, offshore plants, sports equipments, and etc. As broad as its application fields, it also increases welding locations. Conventional GTAW and GMAW are very popular welding methods of titanium, but it has a high heat input and wide HAZ. It has a possibility of inducing Stress Corrosion Cracking. So, laser welding method has been using to get reliable welds by reducing heat input. Weld beads change its color to silver, gold, brown, blue, and gray by shied conditions. And the closer to gray, the more oxidize, nitride and embrittlement. The most effective atom to embrittlement was nitrogen. And shield gas flow was not so effective over the constant flow rates. In this study, weld properties of the pure titanium were investigated by pulsed & CW Nd:YAG lasers and evaluated by various shield conditions. And It is observed that nitrogen is more effective to oxidation and embrittlement of titanium compared with oxygen by oxygen and nitrogen quantitative analysis.

• International Journal of Aerospace System Engineering
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• v.7 no.1
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• pp.16-20
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• 2020

The recent trend is increasing towards the usage of polymer matrix composites since they have a wide variety of applications. They have applications in the field of aircraft and space industry, sporting goods, medical devices, marine and automotive applications and also in commercial usage. The most commonly used fibre-reinforced polymer matrix composite is Glass fibre reinforced epoxy (GFRE) composite which is used in aviation, sports and automotive industries. However, the strength of GFRE composites is not adequate for structural applications. Therefore, the current research focuses on increasing the strength of GFRE composites by reinforcing with micro Graphite (Gr) particulates. The Gr used is an ultra-fine powder with particle size 250 ㎛. Gr is known to have good wear resistance, thermal conductivity and can operate at high temperatures. Gr particulates are mixed with the epoxy matrix in various weight ratios. Hand-lay technique is used for fabricating the composites. Mechanical properties such as tensile strength, elongation, compressive strength and flexural strength are obtained experimentally to study the effect of change in Gr content (0-5 wt. %). The tests were done as per ASTM standards.

• Journal of Navigation and Port Research
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• v.36 no.7
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• pp.545-552
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• 2012

Domestic marina facilities today consist mostly of composite-type marinas with particular spatial composition characteristics, due to the regulatory restrictions that keep their development in the public sector and the tepid growth of marine leisure-sports. To develop a marina club design appropriate for domestic conditions, this study establishes space program standards for designing Korean marinas based on a case analysis of existing marina clubs and a survey of floating marina clubs. It is possible for a current composite-type Korean marina club to have a spatial composition of 16~18% for marina-exclusive facility (mFA), 47~49% for commercial facility (cFA), 27~30% for public space (pFA) and 5~8% for management space (emFA). With this composition as a basis, space program estimation of a Korean marina club can be done through the process of estimating in order the marina-exclusive facility area, the floor area by each space and the total floor area, the first floor area, the deck area and the pontoon area. Since the space program established in this study can be utilized as a tool for designing a Korean marina club, it is expected to be helpful in designing marina clubs in the future.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.2
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• pp.108-114
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• 2016

Recently, there has been a growing interest in marine leisure sports and high speed power boat for fishing. The prototype of 20 feet class power boat was developed and authors are joined in this government-led project. The research was performed to evaluate the optimal structure and design of the structural strength necessary to ensure the structural safety of the power boat. A new material ROCICORE fiber added to the mat and roving was adopted for high-power tenacity. ANSYS Workbench has been used to make the structural model, evaluate the strength and optimize the structural design. The response of the structure to quasi-static slamming loads according to the rules and regulations of ISO 12215-5, Lloyd’s Register of Shipping and Korean Register has been implemented and studied. An optimization study for the structural response is carried out by changing the plate thickness and section modulus of stiffeners. The power boat structure derived fuel efficiency is optimized by performing the best possible structural design to minimize the hull weight.

• Korea Trade Review
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• v.45 no.5
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• pp.23-35
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• 2020

The purpose of this study is to examine relationships among exhibition selection factor, performance, satisfaction and intention to revisit of participants in international exhibition. For this purpose, we set hypotheses relationship among external selection factor of exhibition (ESFE), internal selection factor of exhibition (ISFE), performance of sales (PS), performance of information gathering (PIG), performance of relationship building (PRB), performance of image building (PIB), satisfaction (SAT) and intention to revisit (IR). To verify theses hypotheses, we conducted path analysis on the data from 100 participants of 2019 Korea International Boat Show. The result of this study is as follows: Frist, ESFE positively impacts on PS, PIG, PRB, PIB. Second, ISFE positively impacts on PIG, PRB. Third, PS and PIB positively impacts on SAT. Fourth, SAT positively impacts on IR. The implication of this study is two fold. This study expands research area of international exhibition to a new industry such as marine leisure sports industry and provides useful information to firms that plan to participate in the international exhibition and to those who organize the international exhibitions.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.561-568
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• 2020

A performance analysis was conducted according to changes in inflow velocity and the tip speed ratio of a portable horizontal-axis hydro turbine that can be used for marine leisure sports and outdoor activities by using the commercial computational fluid dynamics software ANSYS CFX. By using the analysis result and flow field analysis, the design was reviewed and the performance of the device was confirmed. In addition, data necessary to improve the performance of the hydro turbine were acquired by performing an additional performance analysis according to the variable blade pitch angle. The results among the numerical analysis cases show that the highest performance at all inflow velocities and blade pitch angles if achieved at a tip speed ratio of 4. The output power was found to be 30 W even under some conditions below the design flow rate. Among the numerical analysis cases, the highest output power (~ 85 W) and power coefficient (~ 0.30) were observed at an inlet flow rate of 1.5 m/s, a blade pitch angle of 3°, and a tip speed ratio of 4.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.5
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• pp.406-415
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• 2012

The research aims to provide its results to each municipal corporation after an in-depth analysis of its optimum demand and also the significance of post-development location selection. The research results, related to the future development of Marina from the municipal corporation, are as follows: There are approximately 49 proper domestic demands after the Marina development. In further detail, there must be a development of the coastal zone Marina concept after classifying the regions to their Metropolitan areas and networking the Marina to each section. Moreover, the classification of the Marinas to small, medium, and large size is of absolute necessity. Regionally, 10 large Marinas must be developed for metropolitan area (2), Chungcheong area (1), Jeolla area (2), Gyeongsang Provinces (3), Gangwon area (1), and Jeju (1). The 17 mid-sized leisure sports Marinas must be developed for metropolitan area (3), Chungcheong area (2), Jeolla area (2), Gyeongsang Provinces (6), Gangwon area (2), and Jeju (2). The rest of 22 small Marinas must be developed for metropolitan area (2), Chungcheong area (1), Jeolla area (6), Gyeongsang Provinces (9), Gangwon area (2), and Jeju (2). In addition, there is an evident result of significant importance in the domestic positions of appropriate Marina development. A group of professionals suggested five key factors contributed to the importance including accessibility, marketability, usability, validity, and natural environment. The results, aimed to show comprehensive importance based on the five factors, ranks in the following order from highest to lowest: usability, accessibility, natural environment, marketability, and validity.

• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.273-281
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• 2019

This study aimed to qualify the amount of movement during game-based training and competition by using a GPS and to identify the non-contact injury risk in lower extremities for female field hockey enrolled in Korean national team. A total of 52 players were participated in this study and their GPS data collected during training and competition were averaged for 1 week and 4 weeks. And then, an injury risk in lower extremities was calculated for each category of the amount of movement in GPS variables that were related to non-contact injury. In forwards, the injury risk was the lowest in the moderate-low category of total distance covered and repeated high-intensity effort bout and the high category of high intensity distance for 1 week, but the risk decreased as the amount of high intensity distance increased for 4 weeks. In midfielders, the injury risk was the lowest in the low category of total distance covered, high intensity distance, repeated high-intensity effort bout and deceleration bout for 1 week.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.4
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• pp.349-354
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• 2023

Sunscreen is a product that protects against ultraviolet rays by blocking and scattering ultraviolet rays, and has now become a daily necessity beyond cosmetics. Applying sunscreen is a common and easy way to prevent skin damage caused by ultraviolet rays. Due to its significance, the evaluation of sunscreen has evolved since its regulation by the FDA in 1978, progressing to standardized methods established by ISO. Additionally, to assess the loss of sunscreen due to activities such as water exposure or sweating, the Ministry of Food and Drug Safety in Korea and ISO have established protocols for evaluating the water-resistant sun protection factor (SPF). However, existing evaluations of water resistance have been mainly confined to test methods involving plain water, and methods accounting for the impact of seawater during activities like beach leisure, sports, and recreation are yet to be established. Based on the existing guidelines for testing the water-resistant UV protection index, this study compared the water-resistant UV protection index in water, artificial seawater (salt water) and natural seawater (sea water) to evaluate the UV protection index in real-world situations such as marine leisure, sports, and leisure activities. Through these results, we were able to compare the differences between water resistance sun protection index tests in ordinary water, artificial seawater, and natural seawater, and suggest a method for water resistance sun protection index tests using natural seawater.