• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.3
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• pp.1-1
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• 1987

The accurate prediction of the ship wave resistance is very important to design ships which operate satisfactorily in a wave environment. Thus, work should continue on development and validation of methods to compute ship wave patterns and wave resistance. Research efforts to improve the prediction of ship waves and wavemaking resistance are categorized in two major areas. First is the development of higher-order theories to take account of the nonlinear effect of the free surface condition and improved analytical treatment of the body boundary condition. Second is the development of direct numerical methods aimed at solving body and free-surface boundary conditions as accurately as possible. A new formulation of the slender body theory for a ship with constant speed is developed by Maruo. It is quite different from the existing slender ship theory by Vossers, Maruo and Tuck. It may be regarded as a substitute for the Neumann-Kelvin approximation. In present work, the method of asymptotic expansion of the Kelvin source is applied to obtain a new wave resistance formulation in fluid of finite depth. It takes a simple form than existing theory.

• Journal of the Korean Society of Costume
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• v.62 no.3
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• pp.84-95
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• 2012

The purpose of this study is to provide basic data reflecting body characteristics for production of briefs by classifying lower body types of women in their 40s, 50s and 60s. The results are as follows: First, measurements for height-related items decreased while the measurements for width and depth items increased with age. However, 'hip width' and 'hip depth' items showed no significant differences among the age groups. In addition, no visible differences appeared in the length items among the age groups but 'waist to hip' and 'outside leg' lengths showed decreasing values according to age. Second, four factors were established from the factor analysis: 'obesity level around waist and abdomen', 'vertical length of the lower body', 'thickness and obesity level of lower limbs', and, 'size and shape of buttocks'. Lastly, cluster analysis resulted in the classification of the four factors mentioned above. Type 2 appeared the most, representing women in their 40s~60s. Type 1(n=257) was referred as 'slender with a short lower body', Type 2(n=443) as 'plump with short lower body', Type 3(n=224) as 'slender with long lower body', and Type 4(n=199) as 'obese around abdomen and lower limbs'.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.3
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• pp.335-342
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• 1999

The purpose of present research is to develop and efficient numerical method for the calculation of potential flow and predict the wave-making resistance for the application to ship design of tuna purse seiner. Havelock was considered the wave resistance of a post extending vertically downwards through the water from the surface, its section by a horizontal plane being the same at all depths and having its breadth small compared with its length. This enables us to elucidate certain points of interest in ship resistance. However, the ship has not infinite draft. So, the problem which is investigated ind detail in this paper is the wave resistance of a mathematical quadratic model in a uniform stream. The paper deals with the numerical calculation of potential flow around the series 60 with forward velocity by the new slender ship theory. This new slender ship theory is based on the asymptotic expression of the Kelvin-source, distributed over the small matrix at each transverse section so as to satisfy the approximate hull boundary condition due to the assumption of slender body. The numerical results using the panel shift method and finite difference method are compared with the experimental results for wigley mono hull. There are no differences in the wave resistance. However, it costs much time to compute not only wave resistance but also wave pattern over some range of Froude numbers. More improvements are strongly desired in the numerical procedure.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.3
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• pp.260-266
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• 2011

For long slender offshore structures, such as cables and pipe lines, their interaction with surrounding fluid flow becomes an important issue for global design of ocean systems. We employ a long circular cylinder as a representative case of slender offshore structure. A flexibly mounted cylinder in cross-flow generates complex vortex shedding and results in oscillation of the structure. In this paper, flow behind a circular cylinder at Re=100 is simulated. The vortex shedding pattern and flow induced motion are examined in the cross flow configuration as well as with various yaw-angled configurations. The "Lock-in" phenomenon is also observed when reduced velocity is approximately 4.0. The MAC Grid system, which is the typical grid system for Cartesian mesh and pressure correction methods, are used for solving the incompressible Navier-Stokes equations. Predictor/Corrector method is applied for obtaining a non-linear response of structure at the flexibly mounted. The existance and motion of the body is represented by the immersed boundary technique.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.8 s.145
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• pp.1114-1124
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• 2005

The purpose of the paper is to find the elements of jacket pattern far the obese women who went to slenderize their shape by optical illusion. Representative four subjects participated in wear tests. Subjective evaluation of the visual appearance we collected and, at the same time, 3D clothing air volume was observed for the four types of experimental jackets. As results it was found that narrower shoulder width, back upper width, and front waist width resulted in slender look, however, back abdomen width and front shoulder length induced more slender appearance in waist area. The result of the distance between clothing and skin measured by 3D scanner clearly demonstrated the distribution of ease due to the elements of pattern, which is useful to find the pattern variables responsible for the slender appearance of the obese women.

• Journal of Ocean Engineering and Technology
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• v.30 no.2
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• pp.91-99
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• 2016

The global demand for oil and natural gas has increased, and resource development is moving to the deep sea. Floating and flexible offshore structures such as semi-submersible, spar, and FPSO structures have been widely used. The major equipment of floating structures is always exposed to waves, currents, and other marine environmental factors, which cause structural damage. Moreover, flexible risers are susceptible to an exciting force due to the motion of the floating body. The inline and transverse responses from the three-dimensional behavior of a floating structure occur because of various forces. Typical risers are made of steel pipe and applied in the oil and gas development field, but flexible materials such as polyethylene are suitable for OTEC risers. Consequently, the optimal design of a flexible offshore plant requires a dynamic behavior analysis of slender bodies made of the different materials commonly used for offshore flexible risers. In this study, a three-dimensional motion measurement device was used to analyze the displacements of riser models induced by external force factors, and forced oscillation of a riser was linked to forced oscillation under a steady flow and regular wave condition.

• Animal cells and systems
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• v.1 no.4
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• pp.549-552
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• 1997

A new species of Korean ophichthid eel, Ophichthus rotundus, is described on the basis of specimens collected from Kyehwado, Chollabuk-do, Korea. 0, rotundus is characterized by small eye, elongated and slender body, short head and trunk, small eye, long tail, low dorsal and anal fins, many vertebrae, and no spotted pattern on body and fins.

• Journal of Ecology and Environment
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• v.40 no.1
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• pp.1-4
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• 2016

Recent ocean warming near the Korean peninsula and our lack of knowledge of an important vertebrate group, the sea snakes, encouraged us to clarify this part of Korea's regional fauna. We re-examined photographs that had been used to report the slender-necked sea snake (Hydrophis melanocephalus) in 1995. We discovered it was misidentified. To determine the correct identity of the sea snake, we studied 13 original photographs taken at the collecting site in Sooyoung Bay, Busan-si, in 1995 and determined the snake to be Laticauda semifasciata based on enlarged ventral scales, definitive for Laticaudinae sea snakes, and internasal scales, pale blue body color, divided rostral scale, and evident "V"-shaped stripes on the body trunk, definitive for L. semifasciata. Therefore, the snake caught 30 years ago in Korean waters should be considered the first record of a Laticaudinae sea snake in Korean waters. L. semifasciata is listed as near threatened setting the stage for urgently needed studies of sea snakes in Korea and supporting those currently underway.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.497-504
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• 2015

In this paper, we study the propulsive behavior related to the flagellar motion of bacteria using a spring model. A commercial program was used to conduct simulations, and we verified the numerical technique by setting an additional rotating domain and conducting a parametric study. The numerical results are in good agreement with slender-body theory, although overall, they are not in agreement with resistive-force theory. We confirm the effect of the rotational velocity, pitch, helical radius, fluid viscosity, and, in particular, the distance from the wall on the propulsion of the spring.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.197-202
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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 wail. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic interaction forces between ship and bank wail is applied. The hydrodynamic interaction forces acting on a ship during passing through the proximity of the bank wail 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.