• Journal of KIISE:Computer Systems and Theory
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• v.27 no.9
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• pp.768-776
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• 2000

본 논문에서는 심혈관 조영영상으로부터 좌심실의 형태 및 운동을 가시화하기 위해 기하학적 정보와 물리적 정보를 통합한 동적 가우시안 블럽(dynamic gaussian blob)모델을 개발하였다. 동적 가우시안 블럽 모델은 superellipsoid에 3차원 가우시안 형태함수를 갖는 단일 유한요소를 통합한 것으로, 좌심실에 작용되는 가상적인 힘에 의해 형태를 적하하고, 심박동 전 주기에서의 운동을 추적한다. 또한 벽 운동 정도에 따라 다른 색을 지정하여 볼 수 있도록 함으로써 벽 운동에 이상이 있는 부위를 육안으로 쉽게 판별할 수 있도록 하였다. 이와 같은 좌심실의 동적.색체 가시화는 형태가 변황되는 심장질환이나 허혈이나 심근경색증처럼 심실벽 운동에 이상이 있는 질환의 진단을 도울 수 있다.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.435-448
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• 2009

The purpose of this study was to investigate the kinemaitc gait parameter of lower extremities with different gait conditions(level walking, stairs, ramp) in old adults. Fourteen healthy older adults participated in this study and kinematic data were measured using 3D motion analysis system(Vicon, Oxford Metrics, England). Statistical analysis was used one-way ANOVA to know the difference of lower extremities angle at each gait phase with a different gait conditions. In sagittal plane, pelvic anterior tilt increased in stairs and ramp climbing and hip and knee flexion increased in stairs climbing but ankle dorsiflexion increased in ramp climbing. In frontal plane, pelvic was up in stairs and hip abduction and adduction more changed in stairs climbing than level walking. Knee varus and ankle inversion increased in stair climbing. In horizontal plane, pelvic internal rotation increased in stairs and ramp climbing and knee internal rotation increased in stairs climbing but ankle external rotation increased in stairs climbing. This results was shown that the stairs and ramp climbing changed the kinematic gait parameters of lower extremities in healthy old adults.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.538-542
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• 2015

The transverse moment of inertia is an indispensable factor in analyzing the roll motion characteristics of ships and the calculating method needs to be based on the more reasonable theories when deciding the value as the results and reliability of analysis could be much affected by the correctness. However, the mass distribution and shape of hulls are quite complicated and give much difficulties in case of calculating the value directly from the ship design data, furthermore even acquiring the detailed design data for calculation is almost impossible. Therefore some simpler ways are practically adopted in the assumption that the gyradius of roll moment can be decided by a given ratio and hull width. It is well known that the responses of the free roll decay are varied according to the value of roll moment in view of roll period and amplitude decay ratio, so that the general formula to get the moment value can be derived also from the observation of roll decay responses. This study presents how the roll period and decay ratio are interrelated each other from the roll motion characteristics with suggesting a general formula to be able to calculate roll moment from it. Finally, the obtained general formula has been applied to a ship data to check the resultant characteristics through analyzing graphs and showed that the roll moment becomes more accurate when rolling period and decay ratio are considered together in calculation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.235-242
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• 1985

The mechanics of the walking shrimps is useful to clarify the fishing mechanisms in relation to the fishing gears. The gaiting behaviour concerning step positions and step timings on the flat board and the nettings, 16, 23 and 37mm in mesh size were experimented in the aquarium using video camera from June to October, 1984. It was found that the irregular movements of walking legs in step positions and step patterns were appeared on the nettings more than the flat surface due to the absence of mechanical contact with the substrates. The mean stride length and coefficient of variation of the periods in the walking shrimps on the flat board were significantly different from those values on the nettings, However, the velocity, the period and the ratio of forestroke to backstroke were unsteadily changed with the carapace length, and showed little difference under the four conditions. The mean phase difference on the flat board was greater than those values on the nettings which were decreased, while standard deviation on the flat board was smaller than those values on the nettings which were increased with increasing in mesh size.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.3
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• pp.71-82
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• 1999

Irregular motions of nonlinear dynamic system are the result of an intrinsic characteristics that the system have, and sometimes occur unpredictable large motion. For a ship in a regular seaway, the capsizing occur because of this unexpectable motion. So, from the safety's point of view, nonlinear ship motions should be treated carefully. In this study, stable and unstable regions are investigated firstly under the variation of a control external force. Secondly, we consider the attractors to know how ship motions of the stable region that does not undergo capsizing change. Thirdly, bifurcation diagram is considered to study the range in detail where nonlinear chaotic motions are occurred.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.15-22
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• 2016

분자의 진동(특히, 뒤틀림 운동)은 분자의 반응성과 동역학적 특성을 결정하는 중요한 요인이다. 특히, 분자내 메틸기의 뒤틀림 운동은 매우 흔히 관찰되지만, 이 운동을 분광학 실험으로 관찰하고 이론적으로 설명하는 것은 여전히 어려운 과제이다. 여러 양자화학 소프트웨어가 상용화되어 있지만, 뒤틀림 운동과 같은 주기적인 퍼텐셜 에너지를 갖는 운동을 기술하기 위해서는 뒤틀림 운동을 위한 양자화학 솔버가 필요하다. 따라서, 우리는 EDISON의 양자화학 솔버(1차원 슈레딩거 방정식(LagChem), 작은 유기 분자의 분광스펙트럼 분석을 위한 양자 소프트웨어(SGU-QASSO))들을 이용하여 $2-C_3H_5Br$의 ZEKE/MATI (J.Chem.Phys.119,12351(2003),Zero kinetic energy/mass-analyzed threshold ionization)스펙트럼을 이해하고 해석해보았다. $2-C_3H_5Br$ 분자는 메틸기의 강한 뒤틀림 운동을 관찰 할 수 있는 비교적 간단한 분자이기 때문에 뒤틀림 운동 분석을 위한 실험대상으로 적절하다(J.Chem.Phys.119,12352(2003)). $2-C_3H_5Br$ 분자의ZEKE/MATI스펙트럼의 결과는 EDISON양자화학 솔버를 통해 성공적으로 재현되었다. 각 진동 전이의 진동수와 세기는 실험 결과와 일치했으며, 진동 상태에 따른 파동 함수도 구할수 있었다. 이를 바탕으로 thietane 분자와 같은 고리분자의 ring-puckering운동에 대해 이해하려 한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.5
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• pp.28-33
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• 2005

Nonlinear aeroelastic characteristics of a two dimensional typical section model with bilinear plunge spring are investigated. Doublet-point method(DPM) is used for the calculation of supersonic unsteady aerodynamic forces which are approximated by using the minimum-state approximation. For nonlinear flutter analysis structural nonlinearity is represented by an asymmetric bilinear spring and is linearized by using the describing function method. The linear and nonlinear flutter analyses indicate that the flutter characteristics are significantly dependent on the frequency ratio. From the nonlinear flutter analysis, various types of limit cycle oscillations are observed in a wide range of air speeds below or above the linear flutter boundary. The nonlinear flutter characteristics and the nonlinear aeroelastic responses are investigated.

• Journal of Ocean Engineering and Technology
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• v.12 no.2 s.28
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• pp.130-138
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• 1998

본 논문은 AUV의 수직면 운동제어를 수행하기 위하여 의사 슬라이딩 모드 제어기를 이용한 모델링 기법과 제어기 설계법에 관한 것으로서, 샘플링 간격이 길어지는 경우에도 시스템의 강인성이 확보되며 심도 제어가 안정적으로 수행되는 실용성을 실험과 수치 해석을 통하여 검증하였다. 제어기는 참고문헌에서 제안한 방법을 이용하였으며, 한국기계연구원 선박해양공학연구센터(KRISO)에서 개발한 VORAM호를 제어 대상 AUV로 선정하였다. PMM 시험으로 얻어진 운동 계수를 이용하여 수치 해석을 수행하였으며, KRISO의 장수조에서 실험을 수행하였다. 수치 해석과 실험 결과로부터 샘플링이 길어짐에 따라 의사 슬라이딩 모드 제어기는 연속계에 대한 슬라이딩 모드 제어기에서 발생하는 과도한 채터링 및 불안정성을 보이지 않았으며, 시스템의 안정성이 확보되고 불확실성에 대하여 강인한 제어 성능을 보였다. 또한, 본 논문에서는 수치 해석과 실험 결과를 근거로 의사 슬라이딩 모드 제어기의 설계를 위한 제어 변수의 선정 기준을 제시하였다.

• Sleep Medicine and Psychophysiology
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• v.10 no.1
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• pp.26-31
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• 2003

Restless leg syndrome (RLS) and periodic limb movement of sleep (PLMS), often concurrent, come under diagnosed disorders of sleep and treatable condition. RLS symptoms are evoked in the limbs at rest and increase in the evening and during the night. PLMS is characterized by periodic episodes of repetitive limb movements caused by muscle contractions during sleep. RLS is often associated with a sleep complaint and PLMS. Both RLS and PLMS represent one of the most commonly encountered sleep disorders in a primary care setting. The circadian rhythm and the presence of PLMS cause sleep disturbances in RLS. The emphasis on pathophysiology includes consideration of central nervous system localization, neurotransmitter, and the role of iron metabolism. Dopaminergic agents are considered the treatment of choice for RLS and PLMS. With proper diagnosis and effective treatment patients' ability to fall asleep and maintain sleep improves, and their sense of well being increases.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.579-585
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• 2003

This paper investigates the whirling, tilting and flying motion of a HDD spindle system supported by FDB experimentally. Experimental setup is built to measure the flying, whirling and tilting motion of the HDD spindle system, and three capacitance probes fixed on the xyz-micrometers measure the displacement of a HDD spindle system in the xyz-directions. This research shows that the tilting and whirling motion is mostly dependent on the centrifugal force and the gyroscopic moment due to the unbalanced mass of a HDD spindle. It also shows that the rotating HDD spindle starts to float to the equilibrium position in the z-direction until the weight of the rotating spindle is equal to the supporting pressure generated in the upper and lower thrust bearing.