• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.132-133
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• 2013

Ship salvage crane is to salvage the equipment safely, this type of crane in the shipyard's large ships or port is being used a lot of container etc. Such a salvage crane was installed on the land and it is built to use the harbour facilities. In this paper, the response amplitude operator and the wave exiting force of floating type salvage crane is calculated and it is performed to structural response estimation.

• Korea Journal of Cosmetic Science
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• v.2 no.1
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• pp.33-46
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• 2020

Cosmetics are representative complex fluids, and there have been many studies focusing on the correlation between the rheological properties and sensory attributes. Various instrumental measurements have been suggested to evaluate the sensory attributes, and one of the most common instruments is Texture Analyzer (TA). Although it is reported that the adhesiveness measured by TA is related to the stickiness of cosmetics, there exists reproducibility problem because measurements with TA are sensitive to application conditions. In this study, an instrumental protocol using rotational rheometer has been set up to measure the stickiness of cosmetics. This protocol consists of two steps. The first step is a preconditioning step, and various types of shear deformations are applied to the samples. The next step is the extensional flow and the axial force is measured. When the amplitude of the shear flow corresponded to the linear viscoelastic region, the axial force is the same as those without preconditioning. On the other hand, an axial force decreases as variation nonlinearity increases. It is because the effects of microstructure changes caused by nonlinear deformation affects the extensional flow. It is worth noting that a new protocol facilitates to evaluate the stickiness of cosmetics in a more systematic way.

• Earthquakes and Structures
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• v.20 no.4
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• pp.457-471
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• 2021

This study aims at providing a simple and effective methodology to define a meaningful characteristic period for special class of earthquake records named "pulse-like ground motions". In the proposed method, continuous wavelet transform is employed to extract the large pulse of ground motions. Then, Fourier amplitude spectra obtained from the original ground motion and the residual motion is simply compared. This comparison permits to define a threshold pulse-period (Tp∗) as the threshold period above which the pulse component has negligible contributions to the Fourier amplitude spectrum. The effect of pulse on frequency content of motions was discussed on the light of this definition. The advantage and superior features of the new definition were related to the inelastic displacement ratio (IDR) for single-degree-of-freedom systems with period equal to one half of the threshold period. Analyses performed for the proposed period at three ductility levels u=2,4,6 were compared with the results obtained at half of pulse period derived from wavelet analysis, peak-point method and the peak of product of the velocity and the displacement response spectra (Sv x Sd). According to the results, pulse effects on inelastic displacement ratio seem to be more important when $\frac{T_p^*}{T}=2$ (T is the fundamental vibration period of system). The results showed that utilizing of the proposed definition could facilitate an enhanced understanding of pulse-like records features.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1055-1058
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• 2002

The movement of bone fluid from the region of the bone vasculature through the canaliculi and the lacunae of the surrounding mineralized tissue accomplishes three important tasks. First it transports nutrients to the osteocytes in the lacunae buried in the mineralized matrix. Second, it carries away the cell waste. Third, the bone fluid exerts a force on the cell process, a force that is large enough for the cell to sense. This is probably the basic mechanotrasduction mechanism in bone, the way in which bone senses the mechanical load to which it is subjected. The mechanism of bone fluid flow are described below with particular emphasis on mechanotransduction. Also described is the cell to cell communication by which higher frequency signals might be transferred, a potential mechanism in bone by which the small whole tissue strain is amplified so the bone cells can respond to it. One of the conclusions is that higher frequency low amplitude strains can maintain bone as effectively as low frequency low amplitude strains can maintain bone as effectively as low frequency high amplitude strains. This mechanism has many similarities with the mechanotransduction of acoustical signals in the ear. These conclusion leads to a paradigm shift in how to treat osteoporosis and how to cope with microgravity.

• Steel and Composite Structures
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• v.14 no.1
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• pp.73-83
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• 2013

In this paper Hamiltonian Approach (HA) have been used to analysis the nonlinear free vibration of Simply-Supported (S-S) and for the Clamped-Clamped (C-C) Euler-Bernoulli beams fixed at one end subjected to the axial loads. First we used Galerkin's method to obtain an ordinary differential equation from the governing nonlinear partial differential equation. The effect of different parameter such as variation of amplitude to the obtained on the non-linear frequency is considered. Comparison of HA with Runge-Kutta 4th leads to highly accurate solutions. It is predicted that Hamiltonian Approach can be applied easily for nonlinear problems in engineering.

• Computational Structural Engineering
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• v.3 no.2
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• pp.67-75
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• 1990

A stepped beam with immovable ends under the free and forced vibrations with large amplitude is investigated by using the finite element method to show the effects of longitudinal displacement, shear deformation and rotary inertia. A modified harmonic force matrix is introduced for analysis of finite amplitude vibration of the stepped beam under uniform harmonic loading and a beam under nonuniform harmonic loading. Numerical examples are analysed for deflections and natural frequencies of stepped beam under various support conditions. Results show that the proposed method is valid and efficient.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.245-248
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• 2000

In this paper, we present the performance of a multi-code parallel combinatory CDMA system using bi-orthogonal modulation under multipath fading channel. In general, the dynamic range of the amplitude of the transmit signal is very large in conventional multi-code CDMA systems, resulting in severe nonlinear distortion due to high power amplifier and thus significant BER performance degradation. Since the number of simultaneously multiplexed code channels in the proposed system is reduced, the proposed system exhibits reduction of peak-to-average power ratio (PAPR) of the transmit signal amplitude with significant BER improvement. We verify the performance of the proposed system by computer simulations under the Vehicular B multipath fading channel model by ARIB.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.6
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• pp.605-615
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• 2003

In practice, it is common to manufacture reference blocks containing simple reflectors to obtain distance-amplitude correction (DAC) curves. However, the construction or DAC curves in this manner requires the use of a large number of specimens with appropriate curvatures and reference reflectors located at various depths. Therefore, less costly and quantitative procedures are strongly needed. To address such a need, in this study, we have developed model-based transfer curves to relate a DAC curve obtained in a particular reference configuration with that for a completely different configuration. An example of transferring DAC curves, using the proposed transfer curves, is given.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.1
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• pp.193-201
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• 1993

Experimental investigation of nonlinear instability of deep-water wave train is performed. Two-dimensional Benjamin-Feir type wave instability and breaking are observed at wave steepness between 0.19 and 0.25 and three-dimensional instability and breaking at wave steepness greater than or equal to 0.31. At the same wave steepness, shorter waves with smaller amplitude are more unstable, with earlier occurrence of breaking, than long waves with large amplitude.

• 한국전산유체공학회:학술대회논문집
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• 2001.05a
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• pp.134-143
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• 2001

Viscous solutions of supersonic jet impinging on a flat plate normal to the flow are simulated using three-dimensional Navier-Stokes solver. The jet impinging flow structure exhibits such complex nature as shock shell, plate shock and Mach disk depending on the flow parameters. Among others, the dominant parameters are the ratio of the nozzle exit pressure to the ambient pressure and the distance between the nozzle exit plane and the impinging plane. In the present study, the nozzle contour and the pressure ratio are held fixed, while the jet impinging distance is varied to illuminate the characteristics of the jet plume with the distance. As the plate is placed close to the nozzle at 3D high, the computed wall pressure at or near the jet center oscillates with large amplitude with respect to the mean value. Here D is the nozzle exit diameter. The amplitude of wall pressure fluctuations subsides as the distance increases, but the maximum pressure level at the plate is achieved when the distance is about 4D high. The frequency of the wall pressure is estimated at 6.0 kHz, 9.3 kHz, and 10.0 kHz as the impinging distance varies from 3D, 4D, to 6D, respectively.