• 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.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.4
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• pp.207-215
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• 2004

Recently, securing a vast land in the land region becomes more difficult and efforts to seek its alternation in the sea area have been increased. As a consequence, the coastal region has been faced to extensive beach erosion problems. In planning offshore structures such as artificial islands, it is necessary to forecast the influence of the structure construction exerting on the beach erosion of the adjacent coast. In the present study, the sediment movement pattern behind offshore structure was examined through a series of three dimensional movable bed experiments, so as to develop the numerical model which forecasts morphological change including beach erosions. The experimental results reveal that the sediment movement patterns of the beach line side and the depth region are separated at a certain boundary line. In details, at the beach side including swash zone the sediment movement becomes dominant, which is governed by a relation between depth contours and incident wave directions, while at the depth region the bed load and suspended load due to the orbit motion of waves are carried by nearshore currents, and both movements are clearly separated at a specified boundary that is related to partial standing wave from the beach. It is expected that these results can be effectively used for verification of a numerical model on morphological change of the coast.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.5
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• pp.21-30
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• 2000

As a means of getting over the linguistic barrier between different languages, a sign-language communication system using CG animation techniques has been studied. In order to generate a kind of sign-language animation in the system, the joint angles of the arms and the hands corresponding to the gesture have to be determined Up to date, however, the values of joint angles have been decided by trial-and-error methods based on the animator's experiences To overcome the drawback, m this paper, we design an integrated keyframe editor of the arms and the hands for 3D sign-language animation with which we can easily and quickly generate the keyframes of the sign-language animation required to build up In the Implemented keyframe editor, the values of joint angles are calculated by using mverse kinematics, and the same transformation matrix is applied to the joints of two arms and twenty fingers Experimental results show a possibility that the editor could be used efficiently for making up the sign-language communication dictionaries needed for inter-communication between different languages.

• Journal of the Korean Society for Marine Environment & Energy
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• v.20 no.2
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• pp.91-99
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• 2017

The parametric study was performed for performance enhancement of wave energy converter(WEC) using a submerged pendulum plate. The wave exciting moment and hydrodynamic moment were obtained by means of eigenfunction expansion method based on the linear potential theory, and then the roll response of a pendulum plate and time averaged extracted power were investigated. The optimal PTO damping coefficient was suggested to give optimal extracted power. The peak value of optimal extracted power occurs at the resonant frequency. The resonant peak and it's width increase, as the height and thickness of a pendulum plate increase. The mooring line installed at the end of the pendulum plate is effective for extracting wave energy because it can not only induce the resonance with the waves of the installation site but also increase the restoring moment in case of PTO-on. The WEC using a rolling pendulum plate suitable for the shallow water acts as breakwater as well as energy extraction device.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.5
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• pp.397-403
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• 2007

Insect and birds in nature flap their wings to generate fluid dynamic forces that are required for locomotion. To develop a feasible flapping MAV, it is of crucially important to study the fundamental relations between flapping motion and thrust generation. In this paper, the onset conditions of the thrust generation of a heaving flat plate is investigated using a Lattice-Boltzmann method. For a fixed heaving amplitude of h/C=0.5, the effect of reduced frequency on the thrust generation is investigated. For several values of heaving amplitude(h/C=0.25, 0.325, 0.50), the effect of reduced frequency on the thrust generation is also investigated. It can be said that Strouhal number is more important rather than reduced frequency in case of thrust generation. It is found that the critical Strouhal number over which the flat plate starts to produce thrust is around 0.1. Thrust is an exponential function of the Strouhal number.

• Journal of Science and Technology Studies
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• v.13 no.2
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• pp.71-110
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• 2013

As a patient has recently been recognized as not a passive object but a subject of medical services, various attempts are being made to strengthen the status of a patient. Medical communication which has been led by a doctor so far is being made with a focus on a patient due to sovereignty of a consumer and activation of medical information. The purpose of this paper is to investigate the process to strengthen the status of a patient as a consumer of health care service through a patient association and consumer movement as medical information becomes public. As the patient centered medical service is creating a variety of health care service market using IT technologies, it has contributed to the improvement on asymmetry of medical information. As the expansion of IT fusion health care market is bringing the fundamental change into the traditional relationship between a doctor and a patient, the medical service market is being re-organized. A patient centered medical service such as expansion of mobile health care model led by a patient is being accelerated.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.1
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• pp.37-49
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• 2000

This paper is for the first essential study on the development of unified finite element formulations for solving problems related to the dynamics/thermoelastics behavior of solids. In the first part of formulations, the finite element method is based on the introduction of a new quantity defined as heat displacement, which allows the heat conduction equations to be written in a form equivalent to the equation of motion, and the equations of coupled thermoelasticity to be written in a unified form. The equations obtained are used to express a variational formulation which, together with the concept of generalized coordinates, yields a set of differential equations with the time as an independent variable. Using the Laplace transform, the resulting finite element equations are described in the transform domain. In the second, the Laplace transform is applied to both the equation of heat conduction derived in the first part and the equations of motions and their corresponding boundary conditions, which is referred to the transformed equation. Selections of interpolation functions dependent on only the space variable and an application of the weighted residual method to the coupled equation result in the necessary finite element matrices in the transformed domain. Finally, to prove the validity of two approaches, a comparison with one finite element equation and the other is made term by term.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.28 no.3
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• pp.69-77
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• 2022

Background: Ankle sprains, and the resulting ankle instability worsen to chronic due to recurrent ankle injuries or sprains, 78% of which are accompanied by posture instability and damage due to changes in the position of the talus of the ankle. The purpose of this study is to investigate the immediate effect of applying MWM taping on the patient's muscle strength and balance ability in patients with chronic ankle instability. Methods: 15 people with MWM taping and 15 people with Kinesio taping were applied, and after applying the taping of the ankle, 10 minutes of walking treadmill and 10 times of forward lunge operation, the change in ankle muscle strength and balance ability was confirmed. The strength test of the ankle was performed using a test device called Biodex system 4 (USA) for the movement of the dorsi-flexion and plantar flexion of the foot, and the balance of the two groups was measured using Biodex balance system (USA) to test balance ability. Results: The comparison of muscle strength changes in the ankle does not show a significant increase in the group applying MWM compared to the group applying kinesio taping (p<.05). In the comparison of equilibrium capabilities, the MWM taping group also showed a significant increase in the MWM taping group compared to the kinesio taping group (p<.05). Conclusion: When applying MWM taping and kinesio taping to patients with chronic ankle instability, there was no significant difference in comparison of muscle strength changes, but there was a significant difference in comparison of balance ability.

• The Journal of the Acoustical Society of Korea
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• v.26 no.8
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• pp.415-425
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• 2007

This paper proposes a method of underwater source localization using the wideband interference patterns matching. By matching two interference patterns in the spectrogram, it is estimated a ratio of the range from source to sensor5, and then this ratio is applied to the Apollonius circle. The Apollonius circle is defined as the locus of all points whose distances from two fixed points are in a constant value so that it is possible to represent the locus of potential source location. The Apollonius circle alone, however still keeps the ambiguity against the correct source location. Therefore another equation is necessary to estimate the unique locus of the source location. By estimating time differences of signal arrivals between source and sensors, the hyperbola equation is used to get the cross point of the two equations, where the point being assumed to be the source position. Simulations are performed to get performances of the proposed algorithm. Also, comparisons with real sea experiment data are made to prove applicability of the algorithm in real environment. The results show that the proposed algorithm successfully estimates the source position within an error bound of 10%.

• Journal of Science and Technology Studies
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• v.4 no.1 s.7
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• pp.1-30
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• 2004

In this paper, I have attempted to show how the environmental controversy surrounding the Saemangeurn Reclamation Project in Korea has been framed as narrow scientific debates. First of all, science, or specifically the Expert Review Pane, has played dual roles in the controversy. On the one hand, it has contributed to illuminating the future environmental impacts of reclamation, by so doing, to providing a momentum to reconsider the project. This has significant meaning that environmental concerns successfully checked the symbolic national project of developmental era through adopting a joint-investigation scheme that guaranteed participation of environmental groups on an equal footing with the government. On the other hand, by limiting the scope and participants of discussion, it fundamentally blocked the possibilities of public debates and deliberative decision-making with full considerations of the political, social, and cultural aspects of the controversy. I have shown that this is due to the realist belief shared by both the developers and the environmentalists in Korea that 'proper' science would disclose the truth. Environmental groups, in particular, were naive in evaluating the role of scientific expertise in the controversy and neglected the political role of the Expert Review Pane as a ritual. In opposition to the realist argument, I have shown through the analysis of the water quality debates concerning the future fresh water lakes that scientific 'facts' were not discovered but constructed through complex negotiations, conflicts, and compromises among related actors. The framing of the controversy as an experts' debate has resulted in the exclusion of an important actor from the discussion. Little attention has been paid throughout the controversy to the very people who have lived in the Saemangeum area for generations and will lose their livelihood all together soon. About 20,000 fishermen are living on the Saemangeum tidal flats.