• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.37-43
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• 2008

The durability test of turbo-blower for PEM fuel cell is very important process of BOP development. It is a major barrier to the commercialization of these systems for stationary and transportation power applications. Commercial viability depends on improving the durability of the air supply system to increase the reliability and to reduce the lifetime cost. In this study, turbo-blower supported by oil-free bearing is introduced as the air supply system used by 80kW proton exchange membrane fuel systems. The turbo-blower is a turbo machine which operates at high speed, so air foil bearings suit their purpose as bearing elements. The impeller of blower was adopted mixed type of centrifugal and axial. So, it has several advantages for variable operating condition. The turbo-blower test results show maximum parasitic power levels below 1.67kW with the 30,000 rpm rotating speed, the flow rate of air has maximum 163SCFM(@PR1.1). For proper application of FCV, these have to durability test. This paper describes the experiment for confirming endurance and stability of the turbo-blower for 500 hours.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.5
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• pp.413-422
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• 2012

The ducted fan for a small UAV propulsion can reconnoiter and observe in a town and a small area, it has better thrust efficiency and a long endurance than propeller. Thrust characteristics of hover and for ward flight condition for the ducted fan UAV is important issue to improve a endurance. The unsteady 3-dimensional flow fields of the ducted fan UAV is essential to stable flight. In this paper, to verify the design results of the ducted fan and to investigate a stable aeronautical characteristic, the thrust performance and the unsteady 3-dimensional flow fields are measured. Thrust characteristics for the hovering and the forward flight conditions are measured by the 6-components balance system in the subsonic wind tunnel. The unsteady 3-dimensional flow fields are analyzed by using a stationary $45^{\circ}$ slanted hot-wire technique. The swirl velocity is almost removed behind the stator blades. Therefore, the thrust performance of the ducted fan is improved and the flight stability is maintained.

• Journal of the Korean Society of Marine Environment & Safety
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• v.11 no.1 s.22
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• pp.23-28
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• 2005

We have investigated the usefulness cf active stabilizing system to reduce ship rolling under disturbances, using varying reaction cf the flaps. In the proposed anti-rolling system for a ship, the flaps as the actuator are installed on the stem to reject rolling motion induced by disturbances like wave. The action induced by flaps which depends on power of disturbances am take the ship balance. Especially, in this study we identify the controlled system under the undefined system structure using spectral analysis and experimental studies. Based on these informations, we design the controller to evaluate the usefulness of the proposed system.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.23 no.2
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• pp.9-16
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• 2017

Background: The purpose of this study was to investigate the relationship between the spine and the flat-foot, the stability and the alignment of the posture of the neck to prevent the alignment of the ankle joint operation and the lower back flexibility of the lumbar region according to the type of treatment using active stretching of the triceps, back pain, and to see how they affect weight bearing differences. Methods: The subjects of this study were 24 chronic low back pain patients. They were randomly divided into experimental group and control group. In the experimental group, ankle joint mobilization and active scraping of triceps were performed three times a week for a total of 6 weeks. The control group was performed in the same way without articulation. The range of flexion and extension motion of the lumbar spine and pain degree and difference of weight-bearing were measured before and after the experiment. Results: The model of ankle joint mobilization and calf muscle elongation of flat foot significantly improved the range of flexion and extension motion of the vertebrae (p<.05) and the VAS and distribution of weight-bearing were decreased in both of two groups (p<.05). In other words, the exercise and mobilization help to recover of the balance of the whole musculoskeletal, the vertebrae. Conclusions: The active exercise of the triceps muscle of the lower leg in this study It affects the flexibility of the lumbar spine, the pain and the difference in the weight support of the lower extremities, when we performed ankle joint mobilization for exercise and cramping, pain and the difference in weight support between the two lower limbs.

• Journal of the Korean Geographical Society
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• v.38 no.1
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• pp.70-86
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• 2003

This study aimes to describe the forms and characteristics of Myungdang tomb sites in Andongs Area by conducting field trips and analyzing on topographic maps. Most Myundang sites are concentrated around hills, mountains, and tributaries that collectively are located in a northern parts of Nakdong river. The river and the mountain, which the principle of Pungsu, so called Jangpung and Duksu, is applied to, constitute the various forms. They provide the sites with physical settings for Myungdang that can be said to commonly retain such properties as semi-openness, multi-surroundedness, stability, harmony, balance. It can be further argued that those properties of Myungdang sites offer criteria for human settlement and sustainable land development in the current world.

• Korean Journal of Plant Resources
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• v.28 no.1
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• pp.135-144
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• 2015

The Korean daily intake of vegetable oils has increased about 2.5-fold from 17 g/day to 46 g/day for the last several decades. Perilla (Perilla frutescens var. frutescens) has been cultivated in Korea for a long time as a dietary oil seed which has the highest content of ${\alpha}$-linolenic acid, accounting for nearly 60%. It is known that the main role of ALA is as a precursor to the longer-chain ${\omega}-3$, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), the metabolic products of ${\alpha}$-linolenic acid (ALA, ${\omega}-3$). Dietary ${\omega}-3$ fatty acids reduce inflammation and the risk of chronic diseases such as heart disease, cancer, and arthritis, but they also may act as functional components for cognitive and behavioral function. Thus, ${\alpha}$-linolenic acid is one of the essential nutrients in modern dietary patterns in which much linoleic acid is consumed. Nevertheless, perilla oil, rich in ${\alpha}$-linolenic acid, can be easily oxidized, giving rise to controversies with respect to shelf life, the deterioration of the product's commercial value, and further related toxicity. Recent research using genetic modifications has tried to develop new plant oil seeds that balance the ratio of ${\omega}-6/{\omega}-3$ fatty acids. Such trials could be a strategy for improving an easily oxidizable property of perilla oil due to high ${\alpha}$-linolenic acid. Alternatively, appropriate application of antioxidant to the oil can be considerable.

• Journal of Digital Convergence
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• v.18 no.4
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• pp.101-112
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• 2020

This study aims to discuss the current status of the ride-sharing platform industry, which embodies the core values of the 4th Industrial Revolution, sharing and connectivity, as well as economic, industrial, and legal issues. To understand the position of competing groups, the research conducted extensive literature reviews on domestic and international cases of technical and legal issues of the sharing economy. The result indicates that the ride sharing industry showed the economy of synthesis in which production, supply, distribution, and consumption are on one platform. It made possible to share values to users and synthesize them with new services through easy-access mobile application technology. To resolve the conflicts between the taxi industry and the ride sharing industry, this study suggests the following: Ride-sharing companies should make contributions to provide legitimate services. The taxi industry needs to understand the value of the new industry and consumers who chose the shared platform service. The significance of the current study is that it proposed a comprehensive analysis and policy direction toward the issue of balance between public and private interests and legal stability.

• Journal of the Korean Solar Energy Society
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• v.40 no.5
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• pp.23-34
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• 2020

Concentrator photovoltaic (CPV) system consists of high-quality complex optical elements, mechanical devices, and electronics components and can have the advantages of high integration and high-efficiency energy sources. III-V compound semiconductor cells have proven performance based on high reliability in the aerospace field, but have characteristics that require absolute support of the balance of systems (BOS) such as solar position trackers, receivers with heat sinks, and housing instruments. To determine the optimum parameters of secondary optical elements (SOEs) design for CPV systems, we designed three types of CPV modules, classified as non-SOEs type, reflective mirror type, and CPC lens type. We measured the I-V and P-V characteristics of the prototype CPV modules with the angle of inclination varying from 0° to 12° and with a 500-magnification Fresnel lens. The experimental results assumed misalignment of the solar position tracker or module design of pinpoint accuracy. As a result, at the 0° tilt angle, the CPC lens produced lower power due to the quartz transmittance ratio compared to that by other SOEs. However, for tilt angles greater than 3°, the CPC lens type module achieved high efficiency and stability. This study is expected to help design high-performance CPV systems.

• Physical Therapy Rehabilitation Science
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• v.7 no.1
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• pp.13-17
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• 2018

Objective: This was a correlation study for predicting the power to improve the distance of golf players and developing an effective power program. Design: Cross-sectional study. Methods: The subjects of this study were 24 healthy males and females in their 20s and 30s who were golf athletes living in Seoul and Gyeonggi-do. In the Titleist Performance Institute (TPI) Level 1 test, the twelve swing characteristics include components of stability, mobility, body conditioning ability, and balance. The power test consisted of a vertical jump (VJ) in order to examine the power of the lower body, the seated chest pass (SCP) was used to examine upper body power, and the sit up and throw (SUAT) was used to examine the power of the upper body and core for the TPI Level 2 test. Results: The results of this study showed that the 90/90 was correlated with VJ, SUAT, and SCP scores (p<0.05). Single leg stance was correlated with VJ, SUAT, over head deep squat, and bridge with leg extension were correlated with VJ (p<0.05). The toe touch was correlated with SUAT results (p<0.05). Conclusions: The results of this study showed that the TPI Level 1 test and power test were correlated with the performance of the golf players. Future studies have shown that fitness program development and further research are needed.

• Journal of Fashion Business
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• v.24 no.3
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• pp.121-137
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• 2020

This thesis makes it an aim to develop designs of Shinhanbok coats interpreting and applying the formative structure of the lattice window pattern in Huijeongdang of the Changdeokgung palace, one of the best architecture in Chosun dynasty. Literature review about the history and characteristics of the window of Huijeongdang of the Changdeokgung palace was performed on the basis of the internet resources and papers, and the examples of the fashion design applying the lattice window patterns were analyzed. Then, three style Shinhanbok coats were designed and presented with making use of 6 kind of lattice window patterns as its motif. The coats were designed in flexible size, attempting to clad any kind of body size and shapes. Design 1 drawn from Wanjasal, Tisal, Design 2 drawn from Ajasal, Yongjasal, Tisal, design 3 drawn from Bitsal, Jungjasal. In conclusion, lattice window patterns of the traditional beauty highlighted in view of modern times might be suggested as the motif for expressing the proportion with balance and rhythm with stability. The division of the space with the line was tried with the technique of the bias cutting, stitching and taping with the design of simplicity signified in the aesthetics of the vacant space in addition to its ornamental effects. Thus, this study would like to contribute to the popularity of the Shinhanbok outlined in modern application and unique taste through the study and applications of the traditional lattice window pattern of Korea.