• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.1
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• pp.33-44
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• 2000

Ships in a seaway will encounter dangerous situation, such as slamming, stranding, and capsizing. The number of capsizing is small, but the loss due to them is very large from the viewpoint of human life, property, and the environmental pollution. The number of capsizing of fishing vessels is about 62% of total number of capsizing, and the half of them is originated from the operational mistake in a seaway. So the dynamics and the capsizing phenomena are to be studied, and the guide for the safe operation of a fishing vessel in a seaway are to be specified. The hydrodynamic forces consist of radiation forces (which are due to the motion of a ship), Froude-Krylov forces (which is due to the incoming waves), and diffraction forces (which is due to the wave and ship interaction). These forces are calculated by well-known strip method. Using the calculated forces, the motion of a ship in a regular sea is obtained. In the real seaway, the waves are very irregular, therefore the statistical analysis is very helpful. In this paper, using the results of the motion in a regular seaway and the wave spectrum, the motion in a irregular seaway are obtained and analyzed.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.4
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• pp.378-387
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• 2016

This study sought to investigate interrelationships and differences of brachial-ankle pulse wave velocity (baPWV), body composition and cardiovascular variables between genders who have been exercised or not in elderly. One hundred fifty participants were classified four groups. Especially out of variables, in male elderly group who had participated in exercise program the PWV range were significantly correlated with muscle mass (r=0.357, p=0.026), SBP (r=0.468, p=0.003), right baPWV (r=0.406, p=0.010), and left baPWV (r=0.333, p=0.038). In male elderly group who had not participated in exercise program, the PWV range were significantly correlated with heart rate (r=0.395, p=0.014), right baPWV (r=0.598, p=0.000), and left baPWV (r=0.602, p=0.000). In female elderly group who had participated in exercise program, the PWV range were significantly correlated with name of diagnosis (r=0.321, p=0.044), SBP (r=0.399, p=0.011), DBP (r=0.545, p=0.000), right baPWV (r=0.648, p=0.000), and left baPWV (r=0.676, p=0.000). In female elderly group who had not participated in exercise program, the PWV range were significantly correlated with age (r=0.471, p=0.003), right baPWV (r=0.836, p=0.000), and left baPWV (r=0.801, p=0.000). The PWV among four groups were not significant different after experiment. However, there were significant differences in the waist/hip ratio (F=9.197, p=0.000), muscle mass (F=74.295, p=0.000), and %fat (F=35.045, p=0.000) from body composition. And there were significant differences in the SBP (F=3.525, p=0.017) after experiment. In conclusion, these data show that regular exercise is associated with arterial compliance (PWV range, right or left PWV) and differed from genders. In other words, this paper may support the concept that regular exercise program may exert a protective effect on arterial compliance, body composition and cardiovascular systems.

• The Journal of the Acoustical Society of Korea
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• v.15 no.6
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• pp.47-51
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• 1996

The Cylindrical Shell Equation is one of the fundamental tools in the study of the noise analysis in the cylindrical shell. Therefore, lot of the acousticians induced many cylindrical shell motion equations.[1] In the Reference[6], we introduced the newly induced cylindrical Shell Equation and Junger and Feit's shell equation[5], and computed the free wave number with the linear Equation with the supposed solution, in the case of the free motion of the shell. In this paper, we compared above cylindrical shell equations by using dispersion curve of free wave number and we describe the physical mean for the dispersion curve with ring-frequency and ring-extention-frequency. With this result, we proves the useful of a newly induced cylindrical shell equation and we can analyse the Structure-Borne Sound of the shell with this equation in the application.

• Journal of the Korean Chemical Society
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• v.41 no.3
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• pp.123-129
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• 1997

In order to consider the reduced mass effects on the out-of-plane ring inversion vibration of 1,3-CHD, the vector-based computer program has been written and the kinetic energy expansion function for the large amplitude ring inversion vibration has been calculated using this program. The structural parameters for the calculations have been determined from the ab initio HF/6-31G** calculation. The potential energy function for the out-of-plane ring inversion vibration of 1,3-CHD has been determined from the kinetic energy expansion function and previously reported low-frequency Raman data. The vibrational Hamiltonian calculation including kinetic energy expansion function made it possible to determine the more reliable out-of-plane potential energy function for the ring inversion of 1,3-CHD.

• Geophysics and Geophysical Exploration
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• v.5 no.2
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• pp.99-107
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• 2002

An analytical forward modeling algorithm was developed for the efficient application to the geotechnical engineering in SASW (Spectral Analysis of Surface Waves) method. for the theoretical dispersion curve, the finite difference method using motion stress vector, which was proposed by Aki and Richards, was employed and verified with two earth models. For the stable and fast calculation, it was found that the model size depending on the frequency range is suitable $1.5\~2$ times bigger than the wavelength.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.215-219
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• 2000

본 연구는 우리나라 연안해역의 파랑특성과 기존에 개발된 방파제의 특성을 근거로 하여 개념만 정립되어 있는 Active Device형 부유식 방파제(그물형 부유식 방파제)의 가능성 검증을 목적으로 수행하였다. 본 논문에서는 그물형 부유식 방파제의 방파효율과 관련한 인자들(부유체의 형상, 홀수, 각부유체간의 연결방식)의 특성을 실험을 통하여 비교 분석하였다. 작은 부유체를 연결한 형태인 그물형 부유식 방파제는 부유체 사이를 지나가는 파랑 에너지를 부유체의 운동으로 소멸시키는 형태이다. 실험결과 부유체가 완전히 Heave 운동만 한다면 상당한 파에너지를 흡수할 수 있음을 알 수 있었다.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.63-68
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• 2000

A very large floating structure has rather small motion characteristics as to the whole body, while the motion at end part of such structure becomes largest due to the elastic motion of the structure. This paper presents on the theoretical result on the relative motion characteristics and green water phenomena of VLFS in waves This phenomena affect not only to strength of the structure but also the determination of depth of structure. To predict motion responses of structure in regular waves, the source-dipole distribution method and F.E.M is used By irregular wave results, the probability of occurrence of green water and response of the structure were calculated.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.57-62
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• 2000

The very large flcating structure which am be used for as airport may be as large as several kilomet wide. The first order wave forces as well as wave drift forces are very important forces on such a very large floating In the present studv, the time simulation of motion responses with dolphin-moored VLFS in waves is presented The coeffcients and wave forces involved in the equations are obtained from a three-dimensionul panel method in the frequc The horizontal drift forces and mooring forces for dolphin systems are taken into account. As for numerical example, analyses are carried out for a VLFS in irregular wave condition

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.546-548
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• 1998

초음파는 초음파 가공기나 초음파 세척기 등에 많이 이용되고 최근 액추에트로서 초음파 전동기가 주목을 받고 있다. 압전 혹은 자기비틀림 효과를 이용하여 얻는 초음파 진동기는 전기-기계 변환효율이 다른 수단에 비하여 매우 높으므로 이것을 이용하여 얻는 초음파 진동은 왕복운동에서 직선 혹은 회전운동으로 변환시키는 연구가 행해지고 있다. 본 연구에서는 진행파 방식의 초음파 전동기를 중심으로 그 회전 원리를 이해하고 모델링 하였다. 외란에 대하여 강인한 제어방식으로 알려져 있는 가변구조제어의 이론을 이해고 회전형 진행파 방식의 초음파 전동기를 이용한 가변구조, 제어에 의한 서보계를 설계한다. 이때 제어방법은 속도패턴을 미리 정하여 두고 그 패턴에 따라 슬라이딩 모드를 사용하여 속도를 제어하여 위치를 제어하는 것이다. 초음파 전동기의 가변구조제어에 의한 위치제어를 컴퓨터 시뮬레이션으로 검토하고 제어 파라미터를 결정하였다. 그리고 인터페이스 보드를 제작하고 컴퓨터와 전동기를 접속하여 실제 제어 알고리즘을 이용하여 초음파 전동기의 제어 실험을 행하였다.

• Journal of Ocean Engineering and Technology
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• v.20 no.4 s.71
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• pp.70-75
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• 2006

A numerical procedure is described for estimating the effects of the multi-directional irregular waves on the motion responses and tension variations of the ISSC-TLP. The numerical approach is based on a three-dimensional source distribution method and a spectral analysis technique of directional waves. The spectral description for the linear system of ISSC-TLP in the frequency domain is sufficient to completely define the motion responses and tension variations. This is because both the wave inputs and responses are stationary Gaussian random processes, of which the statistical properties in the amplitude domain are well known. The numerical results for the linear motion responses and tension variations in regular waves are compared with the experimental and numerical ones, which are obtained in the literature. The results of comparison confirmed the validity of the proposed approach.