• 한국해양공학회지
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• 제27권1호
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• pp.102-108
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• 2013

In this paper time series wave data, which were measured at the Draupner platform in the North Sea on 1995, are used to investigate statistical characteristics of nonlinear wave. Various statistical properties based on time and frequency domain are examined. The Gram-Chalier distribution fits the probability of wave elevation better than the Gaussian distribution. The skewness of wave profile is 0.393 and the kurtosis is 4.037 when the freak wave is occurred. The nonlinearity of D1520 data is higher than two adjacent wave data. AI index of the New Year Wave is 2.11 and the wave height is 25.6m. The zero crossing wave period of the New Year Wave is 12.5s which is compared to the average zero up-crossing period 11.3s. The significant steepness of wave data is 0.077 when the freak wave was occurred. H1/3/${\eta}_s$ does not increases as the kurtosis increases and the values is close to 4. The New Year Wave belongs to highly nonlinear wave data packet but the AI index is within linear focusing range.

• 천문학회보
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• 제40권1호
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• pp.58.1-58.1
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• 2015

Gravitational-wave has been predicted by Einstein's general relativity in 1916, but its direct detection has failed to date despite of the persistent efforts in the last fifty years in the ground-based gravitational wave detectors. In the centennial year of the birth of general relativity, 'advanced LIGO', one of the most promising Earth-based gravitational wave detectors, plans to start commissioning for the successful discovery of gravitational waves. In addition, a pathfinder satellite of eLISA project, a space-based GW antenna by European Space Agency (ESA), will be launched in the mid of this year. In this talk, we review the current status of gravitational waves detection experiments and discuss its scientific impacts and the possibility of opening the new age of astronomy.

• 한국해양공학회지
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• 제33권3호
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• pp.252-258
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• 2019

In this paper, the time history of the surface elevation measured at the Draupner platform in the North Sea in 1995 is used to examine the statistical characteristics of the wave data. The wave statistics for 48 surface measurements, which contain three freak wave occurrences, are summarized. The quartiles, boxplots, correlations, and pair plots of 15 variables, along with the abnormality index, are presented. The kurtosis and skewness of the surface elevation are two variables that are highly correlated with the abnormality index, which defines freak waves. Principal coordinate analysis showed that the direction of the changes in the abnormality index agreed with the changes in the kurtosis and skewness. In addition, various wave heights, except the maximum wave height, showed a similar direction for the height changes, and various wave periods showed a similar direction for the period changes. Based on the correlations and PCA analysis, the kurtosis and skewness of the surface profiles are the two most important variables to predict the abnormality index.

• 통상정보연구
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• 제9권1호
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• pp.427-449
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• 2007

The question of what our cultural goods might have known in a major exporting market, has intrigued investigators since 2000 year. Actually, Maybe Korean cultural assets just didn't have time to get to know International or Asia market. But now, a new euphoria can be tasted, on the lips of the small but growing Korean Contents Mania, as New Korean Wave-Crust begin to welcome the priciest contents from korea. Given Asian's surging population for our entertainment contents-drama, movie, music, character, etc., and the sense of a positive response its newly international market, it is hardly surprising. Now, Korea Wave must play an important roles in our country- economy, business, specially. This paper is seeking in OSMU on Korean Contents in East-North Asian Market, and is developing about Korean Wave study model. and It also points to a different strategy for exporting cultural contents, suggesting it should be effected for model to OSMU.

• International Journal of Contents
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• 제10권3호
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• pp.47-54
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• 2014

Although the Korean Wave originated in China, its presence in this country had been faltering for some time. Recently, however, Korean Wave star centered K-drama via online video websites, Korean Wave TV programs with high ratings, and idol group centered K-pop with glocalization strategies are all popular in China once again. The purpose of this paper is to explore Chinese teens and twenty year olds as the main consumers of Korean popular culture and the how preferred genres, motives, and behaviors of Korean pop culture use and Korean image affect one another. According to the study results, media use via online video service was most common, and among the preferred genres, K-drama has the highest usage rates. In addition, it was discovered that motives and behaviors associated with the use of Korean pop culture had a considerable influence on a positive Korean image.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.105-112
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• 2006

Freak waves in the ocean are recently drawing much attention as a natural disaster to ocean structures and navigating ships as well. Several observation data, among them the Draupner New Year Wave, show the very impressive feature of Freak waves whose wave height is up to three times as high as the significant wave height of surrounding waves, In addition, Freak wave appears as an isolated very high crest in somewhat stationary random waves of same order in their wavelengths. Bearing such characteristics in mind, one notices its extraordinary steepness. This strongly suggests that Freak wave is not long lived but transient nature on the whole. A great number of studies to explain these natures were published from both theoretical and numerical point of view. However it is not sure if they are applicable to actual ocean environment. In this paper, we deal with the results concerning abnormal and/or Freak waves from in-situ ocean wave data and point out several remarks to the problems lain behind the contributions in this context. A physical experiment is described to reinforce the subject discussed from the observation data.

• 한국해안·해양공학회논문집
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• 제24권2호
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• pp.109-119
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• 2012

부산항 신항 인근 해역에서 10년간 파랑 장기 관측을 수행하고, 주요한 파랑 특성을 분석하였다. 부산항 신항은 S계열 파랑이 연중 우세하며, 겨울철에는 거제도 북부 해역에서 발달하는 W계열 파랑이 이에 상응하는 정도로 나타나는 계절적 변동성이 뚜렷이 나타났다. 관측기간 중 유의파고는 대부분 1 m 이하였으나 2003년 9월 태풍 매미 내습 시 최대 유의파고 7.4 m가 관측되었다. 또한, 7월을 제외하고는 계절적 변동성은 거의 없었다. 반면에, 유의파 주기는 평균파향의 영향으로 뚜렷한 계절적 변동성을 나타내었으며, 첨두주기는 여름철에 4~5초, 겨울철에는 3초 내외에 분포하였다. 유의파주기 최대값은 2003년 6월에 관측된 15.56초였다. 한편, 평균파향, 유의파고 및 유의파주기 모두 연별 변동성은 나타나지 않았다. 남측으로 약 4.5 km 떨어진 대죽도 남측 해역에서 5년간 관측된 자료도 함께 분석하여 여름철에는 두 지점 간 높은 상관관계가 존재하는 반면 겨울철에는 그렇지 않음을 확인하였다.

• Ocean and Polar Research
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• 제24권3호
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• pp.263-266
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• 2002

Gravity waves have been searched for with a new all-sky camera system over Korean Peninsular. The all-sky camera consists of a 37mm/F4.5 Mamiya fisheye lens with a 180 dog field of view, interference filters and a 1024 by 1024 CCD camera. The all-sky camera has been tested near Daejeon city, and moved to Mt. Bohyun where the largest astronomical telescope is operated in Korea. A clear wave pattern was successfully detected in OH filter images over Mt. Bohyun on July 18, 2001, indicating that small scale coherent gravity waves perturbed OH airglow near the mesopause. Other wave features are since then observed with Na 589.8nm and OI 630.0nm filters. Since a Japanese all-sky camera network has already detected traveling ionospheric disturbances (TID) over the northeast-southwest range of Japanese islands, we hope our all-sky camera extends the coverage of the TID's observations to the west direction. We plan to operate our all-sky camera all year around to study seasonal variation of wave activities over the mid-latitude upper atmosphere.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.229-236
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• 2002

In this paper, a new novel technique of seismic survey is introduced to estimate the continuity of inclined pits filled with water, It was assumed that the pits would be connected to an abandoned railway tunnel that might be constructed in the past. Thus, detection of pit end was needed for the design of a new highway tunnel(Yukshimreong tunnel) that was likely to be met with a pit. In the beginning of exploration, no reliable, cost effective method was available. Hence, focus of interest moved toward the high impedance contrast(reflection coefficient k∼0.8) between water and rock. In this special model of sequence rock-water-rock, total reflection occurs and the seismic energy, when it is generated in the pit water, is nearly confined to the pit so that seismic waves can propagate much further within the pit. As a matter of convenience, this is called“tunnel channel wave”. With these considerations in mind, seismic detonator(2g) was used as a source at the entrance of pit, whereas hydrophone chain(hydrophone interval=1m) was placed on the bottom of pit. With this appropriate source-receiver arrangement, desirable down-going and up-going waves could be observed that will help conform the continuity of pits. After about one year, it was ascertained that the inclined pit of interest was just nearby crossed with the newly excavated tunnel, as it was predicted.

• 대한전자공학회논문지
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• 제13권2호
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• pp.14-22
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• 1976

본연구는 서부휴전선이북에서 발생되고 있는 잡음파에도 불구 KBS텔레비젼방송의 양호한 시청을 보장하는 안테나를 얻기 위하여 시작되었으며 약 1년에 걸친 연구를 통하여 마침내 전후방비가 30dB정도일뿐 아니라 그 side lobe love 이 -3OdB 이하가 되는 안테나의 개발에 성공하였다. 이 안테나는 VHF TV의 고채널군 전체를 카바하기에 마땅하다고 생각되는 대수주기형으로 제작되었으며 이 안테나를 사용하는 경우 안테나의 후방에서 오는 잡음전파나 반사파에 의해서 수상이 방해되거나 고우스트 즉 2중화면이 나타나는 현상이 현저하게 개선된다는 것이 현지시경의 결과 확인되었다. 이 안테나는 또한 전 side lobe level이 매우 낮음으로써 그 이득이 높으며 TV 가시청지역 확대와 난시청범위의 축소에 그만큼 기여한 것으로 기대된다. This research was started to develop a VHF television antenna which secures good pictures in spite of the disturbance from tile rear side. In a year of research, an antenna which front to banck ratio is gyrator than 30dB and whose side lobe level is smaller than -30dB alas been developed. This new antenna was designed log-periodically for the sake of wide frequency bandwidth which is necessary to cover all tile high channel. And it was found having characteristics of anti-interference against the disturbance wave from tole behind, and anti-ghosts from the reflected waves. Furthermore, the gain of this new antenna is reasonablly high, because of its low side lobe level. After all, the developed antenna is silpposcd to increace the service area considervably and to improve the TV receiving certainly.