• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.172-175
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• 2005

The numerical simulation is performed for the acoustic emission and the wave propagation due to fiber breakage in single fiber composite plates by the finite element transient analysis. The acoustic emission and the following wave motions from a fiber breakage under a static loading is simulated to investigate the applicability of the explicit finite element method and the equivalent volume force model as a simulation tool of wave propagation and a modeling technique of an acoustic emission. For such a simple case of the damage event under static loading, various parameters affecting the wave motion are investigated for reliable simulations of the impact damage event. The high velocity and the small wave length of the acoustic emission require a refined analysis with dense distribution of the finite element and a small time step. In order to fulfill the requirement for capturing the exact wave propagation and to cover the 3-D simulation, we utilize the parallel FE transient analysis code and the parallel computing technology.

• International Journal of Concrete Structures and Materials
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• v.9 no.3
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• pp.307-321
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• 2015

The primary objective of this study is to investigate the feasibility of an innovative surface-mount sensor, made of a piezoelectric disc (PZT sensor), as a consistent source for surface wave velocity and transmission measurements in concrete structures. To this end, one concrete slab with lateral dimensions of 1500 by 1500 mm and a thickness of 200 mm was prepared in the laboratory. The concrete slab had a notch-type, surface-breaking crack at its center, with depths increasing from 0 to 100 mm at stepwise intervals of 10 mm. A PZT sensor was attached to the concrete surface and used to generate incident surface waves for surface wave measurements. Two accelerometers were used to measure the surface waves. Signals generated by the PZT sensors show a broad bandwidth with a center frequency around 40 kHz, and very good signal consistency in the frequency range from 0 to 100 kHz. Furthermore, repeatability of the surface wave velocity and transmission measurements is significantly improved compared to that obtained using manual impact sources. In addition, the PZT sensors are demonstrated to be effective for monitoring an actual surface-breaking crack in a concrete beam specimen subjected to various external loadings (compressive and flexural loading with stepwise increases). The findings in this study demonstrate that the surface mount sensor has great potential as a consistent source for surface wave velocity and transmission measurements for automated health monitoring of concrete structures.

• The Journal of Asian Finance, Economics and Business
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• v.5 no.4
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• pp.201-211
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• 2018

The paper suggests making a policy and strategies for a way of exporting Korean ICT product effectively in the EU and Eastern area, and an effective preparation of 4^th industrial revolution through analysis of preparation status of 4^th industrial revolution of the Visegrad group. Analyze policy, status, what they want for 4^th preparation in the Visegrad group from comparing characteristics analysis of each country's official data, publication data, portal, paper, and etc. They have been preparing for 4^th industrial revolution long time ago as basic research and business before 4^th wave word. With these basic results, they are trying to apply such as, AI, S/W, security, ICT, etc. of 4^th wave core technology. For the development of new export market in EU, the Korean team should research with university and research center or venture company. Through these cooperation, they should understand their personal characteristic, lifestyle, and what consumers want to purchase in EU. And this results can be used in South Asia and India that give a big effect to all over the world ICT market. The external impact of the 4^th wave must have a long-term shift in manpower, and production policy is related to the EU's strategic role, or the preparation of the 4^th wave to the V4 country in the short term.

• Journal of Distribution Science
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• v.14 no.9
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• pp.65-72
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• 2016

Purpose - This study is to examine the effect of Korean Wave (Hallyu) towards consumer purchase intention of Korean Product in Indonesia. In addition, this study also investigates the image of Korea whether it can give an impact on Indonesian consumers' intention to purchase Korean Products. Research design, data, and methodology - A total of 227 respondents from Indonesian consumers were collected using online surveys. The results from this survey were analyzed using principal component analysis (PCA) to identify each of the factors. Multiple regression and process analysis (designed by Andrew F. Hayes) were conducted to test the hypotheses. Results - This research found that 'Korean Wave', 'Ethnocentrism', and 'Country-of-Origin Image' significantly affected consumer purchase intention towards Korean Products in Indonesia, while 'Country Image' on the purchase intention was not significant affected the purchase intention. Conclusions - Study findings provide useful information for business practitioners and government to develop and maintain the use of Korean Wave in the business and marketing fields. By only referring to the image of country, it will be difficult for the consumers to decide whether they want to purchase the products or not. In other words, the favorable image of Korea, usually represented by high level of industrialization and economy, is more likely to be enhanced by favorable image of product and Korean cultural wave.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.04a
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• pp.232-239
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• 1997

The phenomenology of shock loading effects in brittle mass has been of interest to researchers and engineers. The shock loading as blasting causes strong stress waves in the structures. Discontinuous faces due to shock waves interrupt the tensile stress wave propagation and reflect the stress wave propagation. To predict the fracturing behavior of brittle mass, it is required for the numerical method that can analyze the colliding and slipping behavior of discontinuous faces and the wave propagation in the mass, simultaneously In this study, the wave propagation in the brittle materials is analyzed using the modified distinct element method to be able to predict the behavior of discontinuous structures. The behavior of an unsupported bar subjected to loading at the end is analyzed to verify the rigid body motion of a bar and the relative displacement in the bar. The colliding behavior of two bars is analyzed to investigate the propagation of stress waves in the bar. The fracturing behavior of a bar due to impact loading is analyzed to investigate the propagation of stress waves in the bar with and without the discontinuous faces. The applicability of the modified distinct element method to the wave propagation problems is investigated.

• Smart Structures and Systems
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• v.24 no.4
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• pp.525-539
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• 2019

In this study, vibration characteristics of a gravity-based caisson-foundation breakwater system are investigated for ambient and geometric parameters such as various waves, sea levels, and foundation conditions. To achieve the objective, following approaches are implemented. Firstly, operational modal analysis methods are selected to identify vibration modes from output-only dynamic responses. Secondly, a finite element model of an existing caisson-foundation breakwater system is established by using a structural analysis program, ANSYS. Thirdly, forced vibration analyses are performed on the caisson-foundation system for two types of external forces such as controlled impacts and wave-induced dynamic pressures. For the ideal impact, the wave force is converted to a triangular impulse function. For the wave flow, the wave pressure acting on the system is obtained from wave field analysis. Fourthly, vibration modes of the caisson-foundation system are identified from the forced vibration responses by combined use of the operational modal analysis methods. Finally, vibration characteristics of the caisson-foundation system are investigated under various waves, sea levels, and foundations. Relative effects of foundation conditions on vibration characteristics are distinguished from that induced by waves and sea levels.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.4
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• pp.343-351
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• 2019

Green water impact may sometimes cause some structure damages on ship's bow deck. Prediction of proper design pressure against the green water impact is an essential task to prevent the possible damages on bow deck. This paper presents a computational method of the bow deck's design pressure against the green water impact. Large heave and pitch motions of ship are calculated by the time domain nonlinear strip method. Green water flow and pressure on bow deck are simulated by the predictor-corrector second kind upstream finite difference method. This green water simulation method is based on the shallow water wave equations expanded for moving bottom conditions. For various kind of ships such as container ship, VLCC, oil tanker and bulk carrier, the green water design pressures on bow deck are computed and discussed. Also, the obtained results of design pressure on bow deck are compared with those of the classification society rules and discussed.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1858-1868
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• 2021

Resisting an accidental impact of large commercial aircrafts is an important aspect of advanced nuclear power plant (NPP) design. Especially after the 9·11 event, some regulations were enacted, which required the design of NPPs should consider the accidental impact of large commercial aircrafts. Normal working of equipment is important for stopping reactor under an impact when an NPP is in operation. However, there is a lack of reliable analysis and research on the impact test of nuclear prototype equipment. Therefore, in order to study the response of the equipment under high acceleration impact, a centrifugal pump is selected as the research object to perform the impact test. A horizontal half-sinusoidal pulse wave was applied to the working pump. The test results show that the horizontal response of the motor and flange is greater compared to other parts, as well as the vertical response of the coupling. The stress response of the pump body support and motor support is high, hence these parts should be considered in the design of the pump. Finally, combined with the damage and stress evaluation results of the pump under different amplitudes, the ultimate impact acceleration that the pump can withstand is given.

• Journal of Ocean Engineering and Technology
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• v.21 no.2 s.75
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• pp.12-21
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• 2007

As the economy grows and the population increases, we need to develop our coastal area and make use of it for various purposes. Specifically, investigation of the wave interactions on and around the vertical cylinders is very important in the design of the offshore or coastal structures. The nonlinear potential analysis developed so far, although very useful, has been found to be limited in application, as strong nonlinear waves generated by the interference between multilayered cylinders and wave impact forces by breaking waves can hardly be estimated. In this study, using a 3-Dimensional volume tracking method VOF(Volume of Fluid), based on Namer-Stokes equations, was developed to simulate highly nonlinear effects, such as breaking waves at the interface or complicated interference waves among structures. A numerical method for nonlinear interaction wave and vertical cylinders is newly proposed. The wave forces and wave transformations computed by the newly proposed numerical simulation method were compared to the other researcher's experimental results, and the results agree well. Based on the validation of this study, this numerical method is applied to the two vertical cylinders to discuss their nonlinear wave forces and wave transformations, according to the variations of separate distance of vertical cylinders.

• Fashion & Textile Research Journal
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• v.19 no.1
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• pp.40-48
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• 2017

In this study, the impact of the fashion design education on the brain wave and the psychological change of the senior females and its change was intended to analyze. 16 senior females were selected as a subject and the brain wave and the psychology were analyzed before and after the educational program of 4 hours a day for total 3 weeks. Out of the brain wave, the increase of alpha wave represents the mental stability and the comfortable state and its decrease represents the tension and stress. On the contrary, the increase of beta wave represents the tension and the excitation. In the brain wave analysis results, the alpha wave was increased and the beta wave was decreased after the design education program, through which it is deemed that the design education would help to increase the psychological stability and to decrease the tension and the stress in the senior females. In the results of analyzing the psychological test, while the test results for 4 senior females were shown as anxious out of 16 senior females, the BAI score was decreased to 'minor anxiety' after the education and the BAI score was decreased except 2 subjects, through it is deemed that the fashion design education would help to reduce the anxiety in the senior females and it seems that it is coincided with the beta wave analysis results.