• Journal of the Korean Society of Safety
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• v.10 no.3
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• pp.42-46
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• 1995

To purpose of this study is to model design and motion analysis of tangential cam mechanism using personal computer system. The CAD(Computer Aided Design) system used in this study was constructed with CPU(Central Processing Unit) 80486, RAM(Random Access Memory) 8M, CGA graphic card. By using developed program for tangential cam mechanism, we designed tangential cam models and analysed displacement, velocity, acceleration of follower.

• The Journal of Korean Physical Therapy
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• v.13 no.2
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• pp.453-458
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• 2001

The aim of this study is to present the basic reference data of age and specific gait parameters for Parkinson's Disease Patients. The basic gait parameters were extracted from 5 patients, 5 men and 65 years of age using VICON 512 Motion Analyzer. The temporal gait parameters and kinematic parameters is data of Parkinson's Disease Patients. The results were as follows; 1. The cadence, velocity, stride length decreased and single limb support period, double limb support period increased than normal adult in the temporal parameters. 2. The mean angles of joint pelvic tilt and hip, knee, ankle joint decreased than normal adult at kinematic characteristics on sagittal plane. 3. The mean angles of joint pelvic tilt and hip, knee joint has no difference than normal adult at kinematic characteristics on coronal plane. 4. The mean angles of joint pelvic tilt, hip joint no difference and internal, external rotation in ankle joint significantly decreased than normal adult at kinematic characteristics on transverse plane.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.3 s.18
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• pp.69-76
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• 2004

In this paper, an efficient inverse design method for nose shape of submerged body based on the MGM(Modified Garabedian-McFadden) design method has been developed. The MGM design method is a residual-correction technique, in which the residuals are differences between the desired and the computed pressure distributions. 3-D incompressible Wavier-Stokes equation was adopted for obtaining the surface pressure distribution and combined with the MGM design method to perform the inverse design of nose shape of submerged body. The design method was verified by applying to several airfoil shapes. Improved design shapes could be obtained when the method was applied to nose shapes of submerged body.

• Journal of Korean Port Research
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• v.10 no.1
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• pp.37-51
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• 1996

2차의 섭동법과 경계요소법에 기초한 시간영역해석법은 불규칙파의 파동장에 있어서 파-구조물의 비선형간섭을 해석할 수 있는 해석법이지만. 파와 구조물의 운동이 정상상태에 도달하기까지 시간스텝으로 계산을 수행하여야 하므로 계산시간이 매우 길어지고, 각 성분파와 그에 의한 운동요소를 평가하는 것이 어렵다. 반면에 주파수영역해석법은 계산시간이 짧고, 각 성분요소들의 변화특성을 쉽게 판단할 수 있지만, 불규칙파동장으로의 적용이 현실적으로 어렵다는 단점을 가진다. 본 연구에서는 잠제 등에 대해서 전개되어 있는 주파수영역해석법을 임의형상의 부체 구조물에 대해 새롭게 수식의 전개를 수행하고, 압축공기주입 부체구조물에 적용하여 실험 및 이론해석결과로부터 그의 타당성을 확인한다. 이 때 압축공기의 거동은 Boyle법칙을 사용하여 평가한다.

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.2
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• pp.25-31
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• 1989

Two-dimensional large-amplitude motions in regular harmonic wave are treated in time domain, by satisfying the exact body boundary condition and the linear free surface condition. For the present numerical calculation, the method of free-surface spectral representation with simple source distribution on the instantaneous body surface has been extended to include the effect of the incident wave. Calculations of the wave exciting force are performed for a submerged circular cylinder fixed or oscillating with large amplitude. Especially, nonlinear effects on the time-mean forces are studied in detail. It is shown that relative motion between the body and the fluid particle gives a significant effect on the lift and drift forces. Also, large-amplitude motion of a submerged circular cylinder and that of a floating Lewis-form cylinder are directly simulated in time domain. In the calculation results, some nonlinear effects are shown.

• Bulletin of the Society of Naval Architects of Korea
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• v.27 no.4
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• pp.3-14
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• 1990

For a moored body on the sea surface, incident waves with narrow-banded spectra excite the body oscillations of short and long periods. Since the period of slow oscillations can be as long as the natural period of the moored body in horizontal modes, resonance can occur and resulting large motions may cause significant strains in mooring cables. By using the perturbation method of multiple scales, the large slow motion can be analyzed without solving any second-order potentials explicitly. To the leading order, the flows associated with the fast and slow motions interact only parametrically and thus they can be studied separately. It is found that the slow motion strongly depends on the mooring stiffness. In particular, if the moring stiffness is considerably weak compared to the body inertia, the slow motion is highly amplified near resonance. It is also shown that the slow motion is associated with the generation of long waves.

• Journal of Navigation and Port Research
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• v.35 no.6
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• pp.483-488
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• 2011

When a tug-barge navigates in the water, maneuvering ability of a tug is affected by the slewing motion of barge. Therefore it is necessary to decrease the slewing motion of a barge for safe towing work. We chose two different types of barge model and investigated their motion depending on the existence of bridle, towing speed and length of towline. The experiments are performed in the still water using the wire rope for the towline. A longer towline makes the heading angle smaller. The towing speed does not largely affect the turning of barge. Finally, it is noted that the bridle of a towing line decrease the slewing motion of barge more effectively.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.258-261
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• 2011

실내에서 화재가 발생한 경우에 매연의 크기분포 및 형상(morphology) 변화 특성은 경보장치의 작동 및 흡입에 의한 인체피해 등과 관련되어 중요한 연구 분야이다. 이와 관련하여 많은 연구가 이루어져 왔으나 실험에 의한 연구는 각 연구마다 결과치가 정량적 또는 정성적 측면에서 많은 편차를 보이고 있고, 이론적인 연구는 몇몇 특정 조건에 대하여 제한적으로 이루어져 있어서, 실재 구획화재에 적용하는 데는 어려움이 있다. 이 연구에서는 구획화재에 대하여 발열속도이력(history of heat release rate) 및 매연발생률(soot yield) 등에 따른 매연입자의 크기분포 및 형상 변화 해석을 위한 방법을 개발하였으며, 이를 유럽표준시험화재(EN54 Part7)에 규정된 폴리우레탄폼화재(TF4)에 대하여 시험 적용하였다. 이 방법에서는 입자의 크기분포방정식(dynamic equation for the discrete-size spectrum)을 푸는데 있어서 계산시간을 줄이기 위하여 결절방법(nodal method)을 도입하였으며, 또한 실재 화재에서의 매연입자의 성장에 따른 입경범위에 맞추기 위하여 분자운동영역(free molecular region)과 연속영역(continuum region)을 포괄하는 입자크기에 적용되는 충돌빈도함수(collision frequency function)를 사용하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.5
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• pp.420-427
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• 2008

For simulation of a fin unfolding motion for the various aerodynamic conditions, equations and moments applying to the unfolding fin were modelled. Aerodynamic roll moment consists of the static roll moment and the damping moment, which were obtained through wind tunnel tests and numerical analyses respectively. Panel method was used to compute the roll damping coefficient with deflected fin, whose angle was equivalent to angle of attack due to the deployment motion. Roll damping coefficient is a function of angle of attack, sideslip angle, and deployment angle but not of angular velocity of deployment. Simulation with aerodynamic damping model gave more similar deployment time compared to fin deployment test results.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.333-337
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• 2004

It is well known that the hydrodynamic interaction forces between ship and bank wall affect ship manoeuvring motion This paper deals with the interaction effect acting on a ship navigating closely in the proximity of bank wall. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic interaction forces between ship and bank wall is applied. The hydrodynamic interaction forces acting on a ship during passing through the proximity of the bank wall are predicted to evaluate an influence of these interaction forces on ship manoeuvrability. The calculation method used in this paper will be useful for prediction of ship manoeuvrability at the initial stage of design, for automatic control system of ship in confined waterways, for discussion of marine traffic control system and for construction of harbour.