• East Asian Economic Review
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• v.18 no.1
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• pp.83-107
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• 2014

This paper studies the effects of economic development and cultural proximity as common determinants of trade in cultural goods in a dynamic preference selection model. For the empirical analysis, this paper utilizes the gravity framework with importer fixed effects and Poisson pseudo-maximum likelihood estimators. This paper applies the model to Korean export of broadcasting contents to Asian countries. The relative economic development of the export country and the market size of the import country are important determinants of cultural trade, the results of which are generally consistent with traditional goods trade. However, the distance variable does not show much significance, reflecting the unique characteristics of trade in cultural goods.

• Journal of Ship and Ocean Technology
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• v.9 no.4
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• pp.11-22
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• 2005

This paper addresses details of wave load nonlinearity effect on stress RAO and damage ratio using component stochastic fatigue analysis. Traditional spectral fatigue analysis for ship structure is based on linear theory; however, there are a number of nonlinearity sources. Especially loading nonlinearity, such as hydrodynamic pressure applying to ship side and gravity changes due to roll and pitch motion, is thought to critically violate the linearity assumption of spectral fatigue analysis, which involves stress RAO as linear parameter. The main focus is placed on how to idealize complicated characteristics of loading nonlinearity and how to implement the nonlinear bias to linear spectral fatigue analysis.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1233-1236
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• 1996

Attitude Control System for a Hydrofoil type catamaran in wave is designed using a Decentralized Adaptive Control technique which is announced already by authors. This automatic attitude control system is designed for its good seaworthiness and for robustness on the variation of center of gravity. The performance is compared with a PID controller and the results show that the Decentralized Adaptive controller has better stability on the variation of the center of gravity.

• Journal of Ship and Ocean Technology
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• v.7 no.3
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• pp.1-12
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• 2003

The influence of nonlinear phenomena on the behavior of stationary forced flexural-gravity waves on the surface of deep water is investigated, when the perturbation of external pressure moves with near-resonant velocity. It is shown that there are three branches of bounded stationary solutions turning into asymptotic solutions of the linear problem with zero initial conditions. For the first time ice sheet destruction by turbulent fluctuations of atmosphere pressure in ice adjacent layer in wind conditions is studied.

• Geomechanics and Engineering
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• v.31 no.2
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• pp.159-166
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• 2022

The model of two-dimensional plane waves is analyzed in a micropolar-thermoelastic solid with microtemperatures in the context of the three-phase-lag model, dual-phase-lag model, and the Green-Naghdi theory of type III. Harmonic wave analysis is used to hold the solution to the problem. Numerical results of the physical fields are visualized to show the effects of the gravity field, magnetic field, and viscosity. The expression for the field variables is obtained generally and represented graphically for a particular medium.

• Structural Engineering and Mechanics
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• v.59 no.6
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• pp.951-972
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• 2016

The purpose of this study is to illustrate the propagation of the shear waves (SH-waves) in a prestressed hetrogeneous orthotropic media overlying a pre-stressed anisotropic porous half-space with self weight. It is considered that the compressive initial stress, mass density and moduli of rigidity of the upper layer are space dependent. The proposed model is solved to obtain the different dispersion relations for the SH-wave in the elastic-porous medium of different properties. The effects of compressive and tensile stresses along with the heterogeneity, porosity, Biot's gravity parameter on the dispersion of SH-wave are shown numerically. The wave analysis further indicates that the technical parameters of upper and lower half-space affect the wave velocity significantly. The results may be useful to understand the nature of seismic wave propagation in geophysical applications and in the field of earthquake and material science engineering.

• Journal of Ocean Engineering and Technology
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• v.16 no.2
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• pp.1-5
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• 2002

In the past, ports have been mainly developed in natural harbors but nowadays ports are built wherever they can be economically justified. Therefore, construction of breakwater in area that establishment of structure is disadvantageous is risen according to the change of conditions to the location for ports. In case of building gravity breakwater in such point, need that plane shapes of more reasonable section permitting wave overtopping is necessary. One of the earliest methods for solving unsteady incompressible flow including free surfaces is the MAC(Marker And Cell) method by Harlow and Welch (1965). Recently. VOF(Volume Of Fluid) method to improve several drawbacks of MAC method is suggested by Hirt and Nichols(1981) and utilized extensively in fields of hydrodynamics. Wave overtopping phenomenon is simulated including wave breaking for permeable breakwater by numerical analysis and investigated features of wave overtopping behind structure using VOF method.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.3
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• pp.131-139
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• 2014

Infra-gravity waves (IGWs) with a period of 1~3 minutes are a factor that directly influences the motion analysis of moored ships inside a harbor and longshore sediment transport analysis. If significant levels of IGWs from far seas are transferred to a harbor and amplified, they may cause downtime of large ships and induce economic loss. In this study, transfer characteristics of the IGWs intruding from outside to inside Pohang New Harbor were analyzed using statistical analysis and transfer function of wave data measured at both outside and inside the harbor for around 5 years. Transfer characteristic analysis was limited to events where IGWs had wave heights above 0.1 m. The wave height distribution of inside the harbor was similar to that of outside the harbor, while the wave period variance of the former was larger than that of the latter. The parameters of the transfer function was optimally estimated according to each event. The estimated average RMS error of the wave height inside the harbor was around 0.013 m. The estimated parameters had a strong correlation with the linear combination information of IGW wave height, period, and direction (R = 0.95). The transfer function suggested in this study can quickly and easily estimate information on IGWs inside the harbor using IGW information predicted beforehand, and is expected to reduce damage due to unexpected restrictions on harbor usage.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.1
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• pp.60-73
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• 2014

The seaward reverse wave, occurring on the submerged dual porous horizontal plate, can contribute to the reduction of the transmitted wave as it reflects the propagating wave. However, the collision between the propagating and seaward reverse waves increases the water level and acts as a weight on the horizontal plate. This study investigated the characteristics of the wave pressure created by the seaward reverse wave through the analysis of experimental data. The analysis confirmed the following results: 1) the time series of the wave pressure showed reverse phase phenomena due to the collision, and the wave pressures acted simultaneously on both upper and lower surfaces of the horizontal plate; 2) the horizontal plate became repeatedly compressed and tensile before and after the occurrence of the seaward reverse wave; and 3) the seaward reverse wave created the total wave pressure to the maximum towards the direction of gravity, primarily on the upper plate. It was also confirmed that the wave distributions showed a similar trend to the wave steepness. Such outcome of the analysis will provide basic information to the structural analysis of the horizontal plate as a wave dissipater of the steel-type breakwater (STB).

• Journal of the Korean Geotechnical Society
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• v.30 no.11
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• pp.39-49
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• 2014

Volcanic rocks in Jeju island show vesicular structure caused by various environmental factors, and indicate the differences in geological and mechanical characteristics from region to region. Previous studies on the volcanic rocks in Jeju island have been actively conducted on geological and chemical properties in terms of geophysics and geology and on physical and mechanical properties in terms of engineering. But comprehensive comparative analysis on physical and mechanical properties of volcanic rocks in Jeju island is not conducted. In this study, the physical and mechanical properties of volcanic rocks in Jeju island were compared and analyzed comprehensively through the existing research papers and reports about volcanic rocks in Jeju island. As a result, it was found that the relationship between absorption (porosity) and apparent specific gravity is commonly linear and could be represented as two different linear approximations. In addition, it was found that the relationship between P-wave velocity and S-wave velocity and the relationship between absorption (porosity) and uniaxial compressive strength could be classified more clearly, considering two different linear relationships in absorption (porosity) and apparent specific gravity.