• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.121-131
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• 1999

Automatic Rudder Trim System(ARTS) is a device to reduce the pilot's work load for rudder trimming greatly required in varying abruptly aircraft's engine power. This paper represents a technical analysis and a design of control law of the ARTS. The control law of the ARTS is designed based on the analysis of aircraft's characteristics, system's requirements, and limitations. The control law is comprised of open loop control using the rudder trim map for a specific aircraft and closed loop control to compensate the error of the open loop control system. flight test results show that the ARTS can reduce pilot's work load for rudder trimming dramatically and can compensate the aircraft's transient yaw motion.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.2
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• pp.737-744
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• 2019

The study aimed to effect of leisure support and leisure constraints on life satisfaction for extreme sports participants. A total of 368 adults from Seoul, In-chon, Gyeonggi, and Chungcheng-do were recruited. I conducted frequency, reliability, confirmatory factor, correction, and structure equaling modeling analyses using PASW Statistics 18.0 and AMOS 18.0. The results were as follows: (1) leisure support of extreme sport participants has no influence on leisure constraints; (2) leisure support of extreme sport participants had no influence on life satisfaction; (3) leisure constrain of extreme sports had a positive influence on life satisfaction. The article revealed which sport activity as like leisure activity had influence on life satisfaction, and leisure support of participants were related with life satisfaction. Therefore, we continue need to induce to join a extreme sport as it publicize a good benefits for extreme sport.

• Analytical Science and Technology
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• v.24 no.4
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• pp.290-297
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• 2011

In present, evaluation method for car cabin air quality has been developed in ISO, China, Japan. Also The management standard for new produced car has been applied since 1, July, 2010. To manage car cabin air quality, It is important to evaluate VOC emitted from interior material. In this study, complete component of door trim armrest was evaluated in accordance with ISO 12219-5, cut component was evaluated in accordance with ISO 12219-3. The vapour gas was collected with stainless tube packed with Tenax TA and analyzed with TD-GC/MS. It was confirmed that emission rate of each compounds was difficult in each evaluation method. As a result, to evaluating each components composing door trim armrest, main sources of emitting VOCs in door trim armrest were PP substrate and adhesive.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.656-665
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• 2021

In this study, trim tabs were attached to end of stern hull of a small high-speed vessel of length approximately 10 m and Froude number 1.0 to improve resistance performance and passenger comfort. Before computational fluid dynamics (CFD) simulations to assess the performance according to various geometries of the trim tab, the scale effect had been found through a previous study, so full-scale simulations were performed. The trim tab chord length was set to 0.5 %, 1.0 % and 1.5 % of L_PP, and its angle to base line was varied in intervals of 5°. It decreased trim by stern and flotation: the greater the angle and length, the greater was the effect. Then it had pressure resistance decreased and shear resistance increased, and reduction ratio of total resistance varied accordingly. The results of this study indicated that the resistance performance was improved about 27 % at optimal running attitude that was the trim by stern about 1.5°.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.10
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• pp.859-870
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• 2021

KARI (Korea Aerospace Research Institute) is developing a design framework for the concept and preliminary design of eVTOL aircrafts. A low fidelity mission analysis tool was developed for the eVTOL aircrafts of Lift-Tilt Concept, which have tilt propellers and lift propellers, using open source SUAVE package. For its development, a review for the propeller performance analysis functionality was made. To find the trim solution at each mission segment automatically, an algorithm is implemented, using a global optimization technique through parallel processings and DOE(design of experiment). Using the tool, the one seated eVTOL OPPAV(optionally piloted personal air vehicle) was modeled and evaluated, which results were compared with the preliminary design data.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.31-39
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• 2013

A Quad Tilt Wing UAV is a new concept hybrid UAV having the advantages of both fixed-wing and rotary-wing aircraft. This paper presents longitudinal flight dynamic characteristics of a Quad Tilt Wing UAV. The designed Quad Tilt Wing UAV is a configuration of a tandem wing type aircraft with an actuating motor and propeller mounted at each wing. Momentum theory is used to calculate the thrust, and nonlinear modeling is performed considering lift and drag generated by slip stream effect of propellers. Also, Force and moment variation at each tilting angle is considered. Static trim on longitudinal axis is analyzed via numerical simulation. Componentwise force contribution was analyzed at each trim mode. Dynamic characteristics were evaluated through eigenvalue analysis for a linear model at each flight mode. It is verified that longitudinal dynamic characteristics are changing from unstable to stable state by continuous transition of dominant poles.

• Journal of Navigation and Port Research
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• v.38 no.2
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• pp.147-154
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• 2014

The purpose of this study was to identify the correlation among participating in the extreme sports, the flow experience and the satisfaction of life. 420 participants of the extreme sports were selected by the Judgement Sampling Method. Factor analysis and multi-regression analysis have been conducted. The conclusion is as follows. First, the participants' life satisfaction is partially affected by the duration period and term. Second, period, frequency, duration partially effect to life satisfaction. Third, flow experience partially effect to life satisfaction.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.1070-1077
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• 2022

The International Maritime Organization has recently strengthened its marine environment regulations. The energy efficiency index has long been an important indicator of ship design, and now, energy efficiency is being enforced for existing ships as well as new ships. To increase the energy efficiency of existing ships, methods such as retrofitting the bow bulb, selecting an optimized trim during ship operation, and installing an energy saving device have been applied. In this study, the ship resistance was numerically simulated using computational fluid dynamics (CFD) under various bow and stern trim conditions. In addition, the bulb was redesigned to further improve the resistance performance under the selected trim conditions. When the improved bulb was applied, the effective horse power increased by approximately 5%. It is, however, necessary to verify whether the redesigned bulb can reduce ship resistance in waves.

• Journal of Fisheries and Marine Sciences Education
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• v.9 no.2
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• pp.179-187
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• 1997

Doppler log and current meter are based on the measurment of the doppler effect. Ship's speed over the ground measured by means of doppler log effect of underwater ultrasonic intends to get infulence by the difference of sound velocity, the ship's course, the sea bottom inclination, the trim and tranducer installation etc. This paper investigated on the error of speed over the ground by change of the trim comparing the real speed obtained by the mile post with the speed of single beam type doppler log on the trainning ship Kyeongyangho. The results are as follows ; 1. Indicating speed of doppler log is very much greatly influenced on variation of trim, but the real speed is less affected variation by trim. 2. The range of variation and error of speed over ground are smallest when ship's trim is 2.15m trim by the stern.

• Proceedings of the Korea Contents Association Conference
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• 2018.05a
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• pp.179-180
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• 2018

최근 N스크린 세대의 새로운 소비 주도층인 밀레니얼세대(10대~20대 초반)의 증가로 모바일 YouTube 동영상 시청자가 증가하였다. 이로 인해 광고 노출 가능성이 높아지고 있어 YouTube 인스트림 광고가 광고주들의 높은 주목을 받고 있다. 그러나 현재 광고 게재에 따른 정확한 노출 효과에 대한 연구 분석 자료는 현저히 부족하다. 이에 모바일 YouTube 동영상 시청자 수가 가장 높은 10대~20대 초반을 대상으로 국내 YouTube 인스트림 광고 사례 10개를 선정하여 선택적 시청에 따른 시청자들의 행태 파악과 광고 몰입도를 분석해 보았다. 분석 결과 소구 유형별 광고 몰입도는 이성소구보다 감성소구가 컸으며, 그 중 유머소구의 광고 몰입도가 가장 크게 나타났다. 본 연구 결과가 향후 광고 노출 효과를 높이는데 도움이 되기를 기대한다.