• 대한조선학회논문집
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• 제54권3호
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• pp.227-241
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• 2017

In this study, a Volterra system for the variations of metacentric height (GM) in waves is employed to simulate the parametric roll phenomena of ships in head sea condition. Using the present Volterra system, the transfer function of each harmonic component in the GM variation is computed for different ship models, including mathematical models and a real containership, and the results are validated through the comparison with the values obtained using the direct calculations based on a weakly nonlinear time-domain method. Then, a semi-analytic approach employing a 1-degree of freedom equation for roll motion is developed to simulate the parametric roll motions in irregular waves. In the derived approach, the nonlinear and time-varying restoring forces in the waves are approximated using the Volterra system. Through simulations of the parametric roll for different sea states, the effects of the 1st and 2nd-order harmonic components of the variations in the occurrence and amplitude of the parametric roll motions are investigated. Because of the strong nonlinearities in the phenomena, a stochastic analysis is conducted to examine the statistical properties of the roll motions in consideration of the sensitivities and uncertainties in the computations.

• 한국운동역학회지
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• 제25권2호
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• pp.149-155
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• 2015

Purpose : Recently, many researchers and golf coachers demonstrated that X-factor and X-factor stretch had a co-relationship with driving distance. However, its relationship is still controversial and ambiguous. Thus, the aim of this study was to examine the relationship among X-factor, X-factor stretch and swing-related factors, including driving distance in elite golfers. Method : Seventeen male elite golfers (handicap: ${\leq}4$) with no history of musculo-skeletal injuries participated in the study. Thirty spherical retro-reflective markers were placed on including the middle point of PSIS, the right/left ASIS, the right/left lateral acromion of the scapula, driver head and shaft grip. All motion capture data was collected at 100Hz using 6 infrared cameras. Carry distance, club speed, ball speed, smash factor, launch angle, and spin rate were collected from radar-based device, TrackMan. Results : Pearson's correlation coefficient method was used to find the correlations among X-factor, X-factor stretch and swing-related factors. Positive correlations between driving distance and other swing-related factors which include club speed(r=.798, p<.001), and ball speed(r=.948, p<.001) were observed. In contrast to the swing-related factors, X-factor and X-factor stretch had no relationship to driving distance. Conclusion : These results indicate that X-factor and X-factor stretch are not key regulators in driving distance.

• 한국컴퓨터그래픽스학회논문지
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• 제17권4호
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• pp.31-40
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• 2011

프로젝터 기반의 가시화 시스템은 가상현실 흑은 체험형 응용에서 널리 사용된다. 그러나 스크린 재질과 반사 성질에 따라 스크린 상의 투사 밝기의 불균일성이 때때로 체험자의 체험을 방해할 수 있다. 이러한 현상은 체험자의 위치를 추적하는 시스템인 CAVE 혹은 운동판 체험 시스템의 체험자가 시스템 안에서 계속적으로 움직일 경우에는 특별히 문제가 될 수 있다. 스크린 화상 상에 밝기의 불균일성을 만드는 이유 중에 하나는 참여자의 눈의 위치로의 프로젝터와 스크린의 스펙큘라 반사이며, 이에 대한 분석은 높은 계산 복잡도가 요구된다. 그래픽 프로세서의 프로그래머블 쉐이더를 이용하여 스펙큘라 라이팅 요소를 계산하는 것과 마찬가지로, 본 연구에서는 밝기의 불균일성을 줄이기 위하여 주어진 스크린 환경 3D 모델을 가지고 수행 시간에 모든 화소의 밝기를 조정하였다. 이러한 목적을 위하여 개개의 스크린 응용에 따른 각도 기반의 밝기 보정 함수를 고안하였으며, GPU 상에서 수행과 접근을 용이하도록 하였다. 두가지 기법이 구현되었는데, 각도 기반의 접근에서 프로덕트 기반의 접근으로 변환과 구간 선형 보간 근사 기법을 구현하였다.

• 대한예방한의학회지
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• 제18권2호
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• pp.115-123
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• 2014

Objective : The objective of this study is to develop a Qigong exercise program to reinforce musculoskeletal system of seniors appropriate for physical strength and conditions of seniors aged 65 years or above based on health Qigong exercise of oriental medicine. Method : Qigong exercise motions that can improve strength, muscular endurance, flexibility, and cardiovascular endurance of seniors were developed by primarily performing literature review of Qigong experts on the fields like oriental medicine, Qigong exercise, physical education and health science and secondarily using motion training for increased validity of motions. Results : The Qigong exercise program for musculoskeletal system of seniors was designed with 12 motions repeated 8 times and 20 minutes per session, including shoulder exercises (alternate turning of left and right shoulders, turning both arms back and forth, holding and lifting elbow to put it aside), waist exercises (wrapping the head with hands to bow, twisting waist while looking at the tip of hand, large spinning of ball, putting hands together to pull back), and knee exercises (going up a down while lifting a rock, balancing the body while lifting a knee, lifting and spreading knees while drawing circle with arms, raising both arms to the side while lifting heels, breathing). Conclusion : Once the effects of Qigong exercise for musculoskeletal system of seniors developed in this study are tested, the program is expected to contribute to development of Qigong exercise, a core part of oriental medicine health improvement project.

• 한국정밀공학회지
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• 제21권1호
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• pp.140-148
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• 2004

A novel rapid prototyping (RP) process, a full-automated transfer type variable lamination manufacturing process (Full-automated VLM-ST) has been developed. In the full-automated VLM-ST process, a vacuum chuck and a rectilinear motion system transfer the EPS foam material in the form of the plate with two pilot holes to the rotary supporting stage. The supplied material is then cut into an automated unit shape layer (AUSL) with a desired width, a desired length, a desired slope on the side surface, and a pair of reference shapes, which is called the guide shape (GS)’, including two pilot holes in accordance with CAD data through cutting in two steps using a four-axis synchronized hotwire cutter. Then, each AUSL is stacked by setting each AUSL with two pilot holes in the building plate with two pilot pins, and subsequently, adhesive is applied onto the top surface of the stacked AUSL by a bonding roller and pressure is simultaneously given to the bottom surface of the stacked AUSL. Finally, three-dimensional shapes are rapidly and automatically fabricated. This paper describes the method to generate guide shapes in AUSL data for the full-automated VLM-ST process. In order to examine the applicability of the method to generate guide shapes, three-dimensional shapes, such as a piston shape and a human head shape, are fabricated from the full-automated VLM-ST apparatus.

• 한국의상디자인학회지
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• 제6권2호
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• pp.111-121
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• 2004

The Mevelana sect is a spiritual Islamic group experiencing spiritual transaction with their god through a peculiar dancing as a form of religious ritual. The Mevelana, a sect of Islamic Sufism, has their head mosque in Konya in Turkey. Although Mevelana sect is regarded as heretic of Islam, it has exerted considerable influence on the Islamic religion through its peculiar religious worshiping form constituted in dancing and reciting poems. Nowadays, Turkey recognizes the Mevelana dancing as their precious cultural legacy of a long history, exerting public information efforts to give it for wider publicity of Turkey to the world. The Mevelana dress with ornament attired for the ritual dancing performance is regarded to symbolize a spiritual medium, which leads to conciliation with the eternity. The straight lines and curved line characteristic of the Mevelana dancer's trousers, skirt, jacket and such mirrors the image of the Orientals, which is in peculiar contrast with the white and gray colors of the dress with ornament. The impression of the spiritual Mevelana dressing in harmony with the dynamic dancing motion goes beyond mere a religious dressing. It is expressive of a graceful and sophisticated modern formative art, of which the mystic design gives an inspiration to the modern fashion. After Poiret, Islamic factors have emerged in the modern fashion. For instance, a hat with Arabic fashion lapel, a Fez hat of Turkish style, harem pants and such are still popular in the modern fashion. It seems probable that the Iraq War would far more activate the influence of Arabic culture to the modern fashion. By making an analysis on the religious background and formative characteristics of the Mevelana dressing, and by giving design examples on how the Mevelanan dressing has been applied to the modern fashion, this research suggests working out new designs by making a renewed application of their characteristics to the modern fashion.

• 한국해양환경ㆍ에너지학회지
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• 제13권2호
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• pp.83-90
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• 2010

해양파 중에서 2개 선체가 가까운 거리에 계류되어있는 경우에 2선체의 운동을 엄밀한 파 중 2 부유체 운동이론에 의하여 계산하였다. 2 선체의 방사 및 산란파 포텐셜은 특이파 수 현상이 없는 주파수영역 Improved Green 적분방 정식으로부터 구하였다. 규칙파 중에서 근접한 2선체가 서로 연결되지 않은 경우와 강체 연결장치로 병렬 계류된 된 경우의 운동 및 강체연결체에 작용하는 6방향 힘과 모오멘트를 해석하는 기법과 수치실험 결과도 보였다.

• 대한정형외과 초음파학회지
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• 제1권1호
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• pp.64-72
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• 2008

주관절, 완관절 주변의 압박성 신경병증은 일상생활의 불편을 초래하는 상지에서의 흔한 신경병증의 하나로 이에 대한 초음파 검사 소견을 바르게 해석하는 데는 정상적인 신경의 구조와 압박성 신경병증의 병리적 변화를 이해하는 것이 중요하다. 압박성 신경병증에서는 특징적인 초음파 소견을 보이는데 압박부위의 신경은 눌려서 편평한 모양으로 나타나고 근위부에서는 고신호강도의 부종성 변화와 신경속 양상의 소실을 보인다. 기본적인 횡주사 및 종주사 영상 외에 관절이나 근육을 동적으로 움직이면서 시행한 초음파 검사는 척골신경이 주관절 굴곡시 삼두박건 내측두와 함께 내상과위로 아탈구 되는 탄발성 삼두박근 증후군이나 능동적 회내근의 수축시 신경압박이 일어나는 원형 회내근 증후군 등에서 신경의 아탈구나 압박소견을 보여준다. 수근관 증후군이나 주관 증후군 등에서는 신경 단면적의 정량적인 계측이나 압박비의 평가가 진단에 도움이 된다. 임상적 검사 및 전기생리적 검사와 병행하여 사용할 경우 초음파 영상은 상지에서의 압박성 신경병증을 진단하는데 있어 매우 유용한 검사방법의 하나이다.

• 정신신체의학
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• 제7권2호
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• pp.241-246
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• 1999

섬망은 두부손상, 혈관성 질환, 뇌종양 등의 중추신경계 질병뿐 아니라 여러 가지 신체 질병(대사 장애 및 내분비장애, 감염, 심혈관 질병)과 약물에 의해 야기되는 각성 수준의 감퇴, 지남력 장애, 수면-각성 주기 장애, 기억력 장애, 지각장애 등을 특징으로 하는 증후군이다. 1) 섬망을 일으킬 수 있는 약물의 하나인 scopolamine(Kimite$^{(R)}$)은 차멀미 예방을 위해 흔히 사용되며 피부 부착형으로 사용하는데 항콜린성 작용을 갖는belladonna akaloid제제이다. 저자들은 차멀미 예방 목적으로 사용된 transdermal scopolamine(Kimite$^{(R)}$)으로 유발된 섬망 2례를 경험하였기에 이를 문헌 고찰과 함께 보고하였다. 두 증례의 공통점은 여자 노인 환자였다는 점, 멀미 예방을 위해 transdermal scopolamine부착 후 여행지에서 갑자기 증상이 발생하였다는 점, 증상이 2~3일이내에 호전되어 추적 관찰상 아무런 이상이 없었던 점 등이다. Transdermal scopolamine(Kimite$^{(R)}$)으로 인한 섬망의 예방을 위해 사용자와 판매자 모두에게 올바른 사용법에 관해 교육하는 것이 필요할 것으로 사료된다.

• 대한의용생체공학회:의공학회지
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• 제31권3호
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• pp.210-216
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• 2010

This study is vestibular electric stimulation applied between the mastoids during quiet standing elicits postural sway. The aim of this study was to characterize the postural sway response to continuous sinusoidal vestibular electric stimulation across various stimulus frequencies and amplitudes. Binaural bipolar sinusoidal vestibular electric stimulation was applied to the skin overlying the mastoid processes of 10 subjects while they stood on a force plate. The position of the center of pressure(COP) and signals at the feet are obtained on an force plate, while the head and whole body center of mass(COM) was measured with motion analysis system. The stimulus conditions included eight frequencies (1/64, 1/32, 1/16, 1/8, 1/4, 1/2, 1, and 2Hz) and six peak amplitudes (0.1, 0.25, 0.5, 0.7, 1 and 2mA). Each subject experienced one trial at each amplitude-frequency pair. The stimuli elicited sway in lateral plane in all subjects, as evidenced by changes in the stimulus frequency. Our results demonstrate that the vestibular system is sensitive to vestibular electric stimulation intensity changes and responds by altering the magnitude of the response accordingly.