• Title/Summary/Keyword: s wave

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Study of Korean Wave's The Origin and the Usage (한류의 어원과 사용에 관한 연구)

  • Jang, Gyu-Soo
    • The Journal of the Korea Contents Association
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    • v.11 no.9
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    • pp.166-173
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    • 2011
  • Asia has shown a tendency that a certain country's culture leads the fashion in turn every 10 years. The trend of Hong Kong movies in 1980's was called 'Hong Kong Wave', the trend of Japanese animation and games in 1990's was called 'Japanese Wave', and then the 'Korean Wave' began in the late 1990's. This term '~Wave(流)' is a Japanese-style term meaning '~way', '~style', '~group', and so on. In the same manner, recent popularity of Taiwanese TV dramas and a particular star that is in fashion in Japan are called 'Taiwanese Wave', and Chinese movies, broadcast, tourism, and etc. are called 'Chinese Wave'. Thus, the term 'Korean Wave' is a part of expression '~wave' used in Japan and it started to be used in the mean time, and was officially used in <韓流-Song from Korea>, a promotion record of Korean pop music, produced by Ministry of Culture and Tourism in Korea. In this paper I propose to correct the error of the term 'Korean Wave', and furthermore, to define a term expressing Korean culture and study for its usage.

Stress Wave Technique for Detecting Decay of Structural Members in Ancient Structures

  • Lee, Jun-Jae;Oh, Jung-Kwon
    • Journal of the Korean Wood Science and Technology
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    • v.27 no.4
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    • pp.43-50
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    • 1999
  • The safety-evaluation of ancient wood structures has been executed with only visual inspection. The application of NDE(nondestructive evaluation) is required because the visual inspection has many restrictions. Among many NDE techniques, the stress wave technique was used in this research. This study focused on evaluating the extent of decay in members of ancient structures, using stress wave nondestructive technique. For application of stress wave technique to ancient structures, the threshold time which divides members into categories according to degree of decay should be determined in advance. Stress wave timer (Metriguard Model 239A) was used in this study, specimens used in this research were the members obtained from six ancient structures. All specimens were identified as Hard Pine(Pinus densiflora S. et Z. or Pinus thunbergii P.) by microscope. Each member was tested with stress wave passing radially through the pith. In this study, the stress wave time of $12{\mu}s$/cm could distinguish between sound and decayed specimens with accuracy of 77.5 percent. Also, decayed specimens could be separated into moderate and severe categories by stress wave time of $20{\mu}s$/cm. Among the three decay location groups (exterior, mixed, interior), the exterior group could be classified into sound, moderate and severe decay with the greatest accuracy. Stress wave transit time was not sensitive to small decay pockets located in interior of the member.

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Prediction of Wave-Induced Current Using Time-Dependent Wave Model (쌍곡선형 파랑모형을 이용한 해빈류 예측)

  • 김재중;이정만
    • Journal of Korean Port Research
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    • v.12 no.2
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    • pp.269-280
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    • 1998
  • A Wave-induced current model is developed in our study and this model is composed with wave transform model and current model. Two types of wave model are used in our study one is Copeland(1985) type which is applied in the offshore region and the other is Watanabe and Maruyama(1984) type which is applied in the surf zone. The depth-integrated and time-averaged governing equation of an unsteady nonlinear form is used in the wave induced current model. Lateral mixing radiation stresses surface and bottom stresses are considered in our current model. Copeland’s(1976) is used as a surface friction formula. Numerical solutions are obtained by Leendertse scheme and compared with Noda’s(1974) experimental results for the uniform slope coastal region test and Nishimura & Naruyama’s (1985) experimental results and numerical simulation results for the detached breakwater. The results from our wave model and wave model and wave-induced current model show good agreements with the others and also show nonlinear effects around the detached breakwater. The model in this study can be applied in the surf zone considering the friction stresses.

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A study on eliminating baseline wander of ECG using approximated S-wave contour (근사 S-파 궤적을 이용한 심전도의 기저선 변동 제거에 관한 연구)

  • Ju, Jangkyu;Lee, Ki Young
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.1 no.2
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    • pp.33-38
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    • 2008
  • The baseline wander of ECG makes difficult to detect P-, Q-, R- and S-wave. This paper presents and compares two method to remove the baseline wander of ECG using slope traceing waves. For the first method that had been proposed already[1], the ascending slope tracing method is used to eliminate baseline wander. And the second method employs the contour of the approximated S-wave to remove baseline wander. These two methods are common to use the slope tracing wave. However, the first one is to get difference signals between the ascending tracing waves and ECG signals, and the other is to remove baseline wander using the contour of the approximated S-wave obtained from descending slope waves. To evaluate these methods, we apply to MIT/BIH database.

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A Study on Elementary School Teachers' Understanding of, Certainty in, and Familiarity with Wave Concepts in Textbook and Teacher's Guidebook (교과서와 교사용 지도서에 제시된 소리의 성질 단원의 파동개념에 대한 초등 교사들의 이해도, 확신도와 친숙도 분석)

  • Jeong, Jaehun;Lee, Jiwon;Kim, Jung Bog
    • Journal of Korean Elementary Science Education
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    • v.35 no.4
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    • pp.389-405
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    • 2016
  • The purpose of this study was to analyze elementary school teachers' understanding, certainty, and familiarity with 13 key concepts of wave physics that are presented in textbook and teacher's guidebook. 123 elementary school teachers answered concept tests and questionnaires. In the results to these tests and questionnaires, teachers demonstrated a high level of understanding and high certainty in understanding with regard to the concepts of sound generation, effect of medium on wave, timbre, wavelength, and trough and crest of wave. For the topics of sound velocity, wave reflection and wave transmission, teachers demonstrated a high level of understanding but low certainty in understanding. With regard to sound propagation, teachers demonstrated a low level of understanding and an improperly high certainty in that low understanding. Teachers lacked knowledge, i.e., displayed a low level of understanding and low certainty in sound strength, sound frequency, constructive interference and destructive interference. In constructive and destructive interference, the teachers also displayed a low level of familiarity. We analyzed the differences in teacher's understanding, certainty, and familiarity according to teacher demographics defined by the teacher's gender, teaching experience with concepts of sound, career, curriculum track while in high school, and major in university. There were no significant differences in understanding, certainty, or familiarity as defined by gender, teaching experience, and career. However, these displays of knowledge were affected by the teacher's curriculum track in high school and their major. These results suggest that the teacher's understanding of, familiarity with, and certainty in wave physics concepts are more influenced by their learning experience than by their teaching experience. Therefore, we suggest additional learning opportunities for teachers (such as teacher training programs) in order to improve teacher knowledge and correct teacher misconceptions in wave physics.

Development of Long Period Wave Observation System based on GPS (GPS 신호를 이용한 장주기 파고 관측 시스템 개발)

  • Kim, Tae-Hee;Gang, Yong-Soo;Lee, Won-Boo;Kim, Dae-Hyun
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.5
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    • pp.682-689
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    • 2011
  • Recently, there are frequent disasters by Swell-like Wave in the coastal area, Korea peninsula. This phenomenon (Swell-like Wave) has long period above 10 seconds compared with wind wave. To prevent these disasters by the long-period wave in advance, it's necessary to observe it in real time. But existing instruments for wave observation can not observe long-period wave because they mainly are aimed to measure the short-period wind wave. Therefore, in this research it is tried to develop the GPS based Long Period Wave Observation System which real time operation can be realzied in the sea.

TWO-PHASE WAVE PROPAGATIONS PREDICTED BY HLL SCHEME WITH INTERFACIAL FRICTION TERMS (계면마찰항을 고려한 이상유동에서 파동전파에 대한 수치적 연구)

  • Yeom, G.S.;Chang, K.S.;Chung, M.S.
    • 한국전산유체공학회:학술대회논문집
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    • 2009.11a
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    • pp.115-119
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    • 2009
  • We numerically investigated propagation of various waves in the two-phase flows such as sound wave, shock wave, rarefaction wave, and contact discontinuity in terms of pressure, void fraction, velocity and density of the two phases. The waves have been generated by a hydrodynamic shock tube, a pair of symmetric impulsive expansion, impulsive pressure and impulsive void waves. The six compressible two-fluid two-phase conservation laws with interfacial friction terms have been solved in two fractional steps. The first PDE Operator is solved by the HLL scheme and the second Source Operator by the semi-implicit stiff ODE solver. In the HLL scheme, the fastest wave speeds were estimated by the analytic eigenvalues of an approximate Jacobian matrix. We have discussed how the interfacial friction terms affect the wave structures in the numerical solution.

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Performance Test of Parabolic Type Equilibrium Shoreline Formula Using Wave Data Observed in East Sea (동해 파랑관측 자료를 활용한 포물선형 평형해안선 식의 타당성 조사)

  • Lim, Chang Bin;Lee, Jung Lyul
    • Journal of Ocean Engineering and Technology
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    • v.32 no.2
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    • pp.123-130
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    • 2018
  • The present study investigated the validity of an equilibrium shoreline empirical formula for real phenomena. Among three types of equilibrium shoreline formulas, Hsu's parabolic type static formula was employed, which is well-known and the most practical for shoreline estimation after coastal or harbor structure construction. The wave data observed at Maengbang beach and the CERC formula on longshore sediment transport were used in the present investigation. A comparison study was only conducted for the case of a shoreline change after the construction of a groyne. Reasonable agreement was seen between the observed wave data and the data obtained under a wave angle spreading function S = 3.5. However, significant changes were observed when S increased. Thus, careful application is required when using Hsu's formula.

Ocular Lens Test using Elastic Wave (탄성파를 이용한 안경렌즈 검사)

  • Joung, Maeng-Sig;Cho, Hyun-Soo
    • Journal of Korean Ophthalmic Optics Society
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    • v.4 no.1
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    • pp.37-43
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    • 1999
  • Ocular lens failure can be verified by measuring the elastic wave velocity diffraction patterns of monochromatic wave applied with elastic wave were detected using optical heterodyne method. The elastic wave velocity was measured by analysing the diffraction patterns. According to measured results of the longitudinal elastic wave velocity of the middle index-refraction and high index-refraction lens are 6588.5575 m/s and 3973.53 m/s, respectively.

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