파랑집중에 의한 다방향 극한파 생성의 효율성에 관한 실험적 연구

홍기용(KEY-YONG HONG),류슈쉐(SHU-XUE LIU),양찬규(CHAN-KYU YANG) 한국해양공학회 2002 韓國海洋工學會誌 Vol.16 No.5

Extreme waves are generated in a model basin based on directional wave focusing. The targeted wave field is described by double summation method and it is applied to serpent-type wavemaker system. The extreme crest amplitude at a designed location is obtained by syncronizing the phases and focusing the directions of wave components. Two distinguished spectrums of constant wave amplitude and constant wave steepness are adapted to describe the frequency distribution of component waves. The surface profile of generated wave packets is measured by wave guage array and the effects of dominant spectral parameters governing extreme wave characteristics are investigated. It is found that frequency bandwidth, center frequency, shape of frequency spectrum and directional range play a significant role in the wave focusing. In particular, the directional effect significantly enhances the wave focusing efficinecy.

WAVE2 Overexpression and Promoter Hypomethylation Is Associated with Poor Clinical Outcome in Hepatocellular Carcinoma

( Hye Ri Ahn ),( Geum Ok Baek ),( Moon Gyeong Yoon ),( Chul Won Seo ),( Suna Sung ),( Ju A Son ),( Jung Woo Eun ),( Jae Yeon Cheong ),( Hyo Jung Cho ),( Soon Sun Kim ) 대한간학회 2020 춘·추계 학술대회 (KASL) Vol.2020 No.1

Aims: Hepatocellular carcinoma (HCC) is the one of the most common cancers and lethal diseases in the world. Wiskott-Aldrich Syndrome Protein Family Member 2 (WAVE2) overexpression overexpression is reported in HCC. However, the regulation mechanism of WAVE2 and its effect on HCC progression is not well-known. We aimed to explore WAVE2 regulation mechanism through methylation study and WAVE2 role on HCC progression through in vitro study. Methods: Methylation status of WAVE2 was determined through profiling of promoter-region DNA methylation in HCC from The Cancer Genome Atlas (TCGA) data. Validation was performed with bisulfite-specific PCR sequencing and methylation-specific PCR analysis in 20 pairs HCC tissues with corresponding non-cancerous tissues. Targeted inactivation of WAVE2 using siRNA was performed in HCC cell lines and cell growth and proliferation were examined. Results: WAVE2 was significantly overexpressed in HCCs compared to non-tumor tissues and associated with poor prognosis in overall survival and disease-free survival of patients in TCGA data. Also, we found inverse correlation between DNA methylation and gene expression of WAVE2, and WAVE2 was significantly hypomethylated in human HCC compared to non-tumor. Targeted inactivation of WAVE2 suppressed cell growth and proliferation of HCC cells, and reduced the metastatic potential of HCC cells by selectively modulating epithelial mesenchymal transition regulatory proteins. Conclusions: We observed that WAVE2 is significantly overexpressed and hypomethylated in HCC. Also, WAVE2 up regulation is associated with poor prognosis in HCC patients. WAVE2 activation might be one of the key mechanisms during liver tumorigenesis and can be a candidate of therapeutic target for HCC.

2차원 조파수조에서의 파 생성 특성 조사

안재열(Jae-Youl Ahn),최정규(Jung-Kyu Choi),김형태(Hyoung-Tae Kim) 한국해양공학회 2013 韓國海洋工學會誌 Vol.27 No.4

This paper investigates the characteristics of waves generated by a flap?type wave maker in a two?dimensional wave channel. Measurements are carried out for various water depths, wave heights, periods, and lengths capacitance-?type wave height gages. The experimental results are shown to satisfy the dispersion relation of the linear wave theory. For waves with a small height and long period, the wave profiles agree well with those of the linear wave theory. However, as the wave height and period become higher and shorter, respectively, it is shown that the wave profiles measured in the present experiments are different from the linear wave profiles, and the measured wave heights are smaller than the target wave heights, which may be due to the non?linearity of the waves. As the wave progresses toward the channel end, the wave height gradually decreases. This reduction in the wave height along the wave channel is explained by the wave energy dissipation due to the friction of the side walls of the channel. The performance of the wave absorber in the channel is found to be acceptable from the results of the wave reflection tests.

[논문 or 기술논문 택일] Study of a Sloping-wall-type Wave Absorber placed in Various Sinusoidal Propagate Waves

ZHEN-Zhong Yuan(원진중),Eui-Chul Jung(정의철),Hee-Chang LIM(임희창) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.5

?;?;Since there has been a rapid progress to understand the dynamics of an offshore floating body under an ocean environment, we undertake to generate the ocean waves in a lab-scale wind-wave flume. The study is aiming to observe and optimize the similar ocean environmental condition as input wave and to reduce the wall reflective wave. Several absorption methods are suggested to optimize the propagate wave by measuring the maximum and minimum of the standing wave envelope. There has been no optimized absorption method, as they highly depend on the wave period and the wave length. One of the methods-two fixed wave gauges measuring two wave heights and one wave phase ? is applied in this study. In the present paper various approaches were used to analyze the results using the flume, by position of probes, with absorber and without absorber, different position, condition and angle of the wave absorber, This paper also focuses on the analysis of fundamental equations which describe the separating method of the incident and reflective wave, and finally we confirm that the wave absorber is highly efficient considering all the permutation and combination. From the study it is clear that there is a change in the wave amplitude at the receiving end then the generated end; wave absorber is a strong source to control the energy of the coming wave. With the changing the period of the wave, the reflectance is increasing when the period becomes larger.

Estimation of Design Wave Height for the Waters around the Korean Peninsula

Lee, Dong-Young,Jun, Ki-Cheon The Korean Society of Oceanography 2006 Ocean science journal Vol.41 No.4

Long term wave climate of both extreme wave and operational wave height is essential for planning and designing coastal structures. Since the field wave data for the waters around Korean peninsula is not enough to provide reliable wave statistics, the wave climate information has been generated by means of long-term wave hindcasting using available meteorological data. Basic data base of hindcasted wave parameters such as significant wave height, peak period and direction has been established continuously for the period of 25 years starting from 1979 and for major 106 typhoons for the past 53 years since 1951 for each grid point of the North East Asia Regional Seas with grid size of 18 km. Wind field reanalyzed by European Center for Midrange Weather Forecasts (ECMWF) was used for the simulation of waves for the extra-tropical storms, while wind field calculated by typhoon wind model with typhoon parameters carefully analyzed using most of the available data was used for the simulation of typhoon waves. Design wave heights for the return period of 10, 20, 30, 50 and 100 years for 16 directions at each grid point have been estimated by means of extreme wave analysis using the wave simulation data. As in conventional methodsi of design criteria estimation, it is assumed that the climate is stationary and the statistics and extreme analysis using the long-term hindcasting data are used in the statistical prediction for the future. The method of extreme statistical analysis in handling the extreme vents like typhoon Maemi in 2003 was evaluated for more stable results of design wave height estimation for the return periods of 30-50 years for the cost effective construction of coastal structures.

퍼머넌트웨이브시 water wrapping 시술이 웨이브효율성에 미치는 영향

최은정,박수향 한국피부과학연구원 2010 대한피부미용학회지 Vol.8 No.4

The purpose of this study was to present basic data for effective procedures and improvement strategies to minimize hair damage at permanent wave. For this, the investigator treated damaged hair with water wrapping procedure, ampoule & permanent wave agent procedure, and permanent wave agent procedure according to the method of reducing agent application and then permanent wave efficiency. In order to find a useful method of procedure for permanent wave, the investigator first produced damaged hair specimen from virgin hair by treating it with the procedure of permanent wave and dyeing (twice) in a cross manner and then carried out an experiment by applying water wrapping procedure (A), ampoule & permanent wave agent procedure (B) and permanent wave agent procedure (C) to the specimen. Study findings are as follows:As for the efficiency of hair wave according to permanent wave procedures, the water wrapping procedure (A) presented a relatively even interval of wave and excellent efficiency in general. The permanent wave agent procedure(C) presented a broad interval of wave and the worst efficiency of wave among the three procedures. 본 연구에서는 환원제 도포방법에 따라 손상된 모발을 워터래핑, 앰플 처치 와 퍼머넌트웨이브제 및 퍼머넌트웨이브제의 시술방법 등을 통하여 시술한 후, 퍼머넌트웨이브 효율성을 측정하여 모발의 손상을 보다 최소화 할 수 있는 효과적인 시술방법 및 개선을 위한 기초자료를 제공하는데 본연구의 목적이 있다. 실험방법은 버진헤어에서 각각의 시료에 퍼머넌트웨이브 2회, 염색 2회, 교차시술 시술과정을 거처 손상된 모발에 퍼머넌트웨이브에 유리한 시술방법을 찾는다는 측면에서 대표적인 실험방법으로 (A)워터래핑, (B)앰플 처치 와 퍼머넌트웨이브제, (C)퍼머넌트웨이브제 시술방법을 선정하여 시술하였다. 본 연구에서 시술방법에 따른 모발의 웨이브 효율성을 분석한 결과 모든 시술방법에서 (A)워터래핑에서는 웨이브 간격이 비교적 일률적이었고, 효율성이 우수하게 확인할 수 있었으며, (C)퍼머넌트웨이브제에서 웨이브 간격이 넓어지고 늘어져 웨이브 효율성이 가장 저하됨을 확인할 수 있었다.

Optimum design of Wave Absorber in Various Sinusoidal Propagating Wave

Zhen-Zhong Yuan(원진중),Hee-Chang LIM(임희창) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12

Since there has been a rapid progress to understand the dynamics of the coastal wave under a sloping-wall-type breakwater, we undertake to simulate the coastal waves and wave absorbers in a lab-scale wave flume. The study is aiming to observe and optimize a similar ocean environment and to reduce the wall reflection in the wave flume. In order to generate the ocean waves in the wave flume, the combination of the flat-type wave generator and wave absorbers is installed at the channel. Two probes for measuring the wave heights (i.e., level gauges) are used to observe the temporal variation of wave surface as well as the phase difference and the maximum (crest)/minimum (trough) points between the propagating waves. In order to optimize the shape and size of propagating waves, several absorption methods are proposed ?vertical-porous-plates absorber, horizontal punching plates absorber, sloping-wall-type wave absorber and active wave absorption, but for the better option of the propagating waves, the sloping-wall-type wave absorbers are chosen and tested in terms of the constitutive filling materials and the location and shape of the frame. This paper also focuses on the theoretical prediction of the wave surface separating them into incident and reflective components. In the result, it clearly shows that the wave absorber with hard filling material has better performance than that of soft material; i.e., wave absorber can be a strong sink to control the energy of the coming wave. In addition, the larger wave absorber becomes, the lower the reflectance be since the larger volume can remove the on-coming wave energy better. Therefore, given that the same condition of absorber is provided, the reflectance becomes bigger as the wave period is longer. Finally, the reflectance of wave would be controlled under 0.1 in this study so that the wave flume would be applied for simulating the offshore environment.

파력발전장치 발전성능평가를 위한 파랑에너지 자료 구축

박지용(J.Y. Park),고태경(T.K. Ko),최종수(J.S. Choi),김경환(K.H. Kim),이정기(J.K. Lee),김길원(G.W. Kim),신승호(S.H. Shin),백원대(W.D. Baek) 한국해양환경·에너지학회 2019 한국해양환경·에너지학회 학술대회논문집 Vol.2019 No.11

파력발전장치의 설계시 설치 대상해역의 정확한 파랑에너지 자료 구축은 장치의 발전성능 최대화와 경제성 확보를 위해 중요한 요소이다. 파력발전장치가 설치되는 해역의 파랑환경에 따라 그에 적합한 장치의 형상뿐만 아니라 전체 에너지변환장치의 구성까지 변화하게 된다. 본 연구에서는 파력발전장치의 설계시 발전성능평가를 위하여 설치적지의 파랑에너지 자료를 구축하였다. 이를위해 제주도 서쪽해안 파력실해역 시험장 해역에 부이식 파고계를 설치하여 2018년 9월에서부터 2019년 8월까지 1년간 파랑을 계측하였다. 계측된 결과를 통해 연간 유의파고-에너지 파주기 분포표를 완성하였고, 파주기별, 파고별, 파향별 특징을 분석하였다. 본 연구를 통해 얻어진 연간 유의파고-에너지 파주기 분포표를 활용하여 추후 연구되는 파력발전장치의 연간 발전성능평가가 가능하고, 파력발전장치의 최적설계를 달성할 수 있다. When designing wave energy converters, establishment of accurate wave energy data in the installation target area is an important process to maximize power generation performance and securing economic feasibility. According to the wave environment of the sea area where the wave energy converter is installed, not only the suitable shape of the device but also the configuration of the entire energy conversion system is changed. In this study, wave energy data for performance assessment of wave energy converter were established. A buoy-type wave measurement instrument was installed in the open sea test site on the west coast of Jeju Island, and the wave was measured for one year from September 2018 to August 2019. Through the measured results, the annual significant wave-energy period scatter diagram was completed, and the characteristics of wave period, wave height, and wave direction were analyzed. Using the annual significant wave-energy period scatter diagram obtained through this study, it is possible to evaluate the annual power generation performance and to achieve the optimum design of the wave energy converter.

Experimental investigation on wave characteristics due to interference of catamaran demi-hulls in waves

Mai Thi Loan,VO ANH KHOA,조애리,Mai Van Thuan,윤현규 대한조선학회 2024 International Journal of Naval Architecture and Oc Vol.15 No.-

The presence of twin hulls of a catamaran has a strong impact on wave pattern in the whole inner region due to interference between waves generated by each demi-hull. Consequently, wave profiles as well as wave height become complicated and unpredictable in the inner region not only in still water, but also in the presence of waves. Determining wave characteristics between demi-hulls of the catamaran is essential for predicting the operation of an autonomous underwater vehicle (AUV) throughout the launch and recovery (LAR) process. This study performed an experiment to investigate wave characteristics between demi-hulls of the catamaran under regular and irregular waves at various wave directions and speeds. The experiment was designed to measure wave elevation in the inner region between demi-hulls in waves using ultrasonic sensors and capacitance wave probes. The experimental method and setting were verified exacting by comparing the motion response of the catamaran measured by the Qualisys system with numerical simulation using the 3D panel method. Then, wave elevation in the inner region was measured and analyzed to wave height which is a representative parameter of regular waves and to wave spectral density and significant wave height which are representative parameters for irregular waves. These parameters were compared to those of the ocean waves to understand influences of wavelengths, sea states, wave directions, and speeds on wave characteristics between demi-hulls of the catamaran. Plotting of difference from ocean waves indicated the discrepancy in wave characteristics among positions in the inner region, wavelengths, wave directions, sea states, and speeds compared to ocean waves. Results of wave characteristics in the inner region are valuable to analyze motion response and behavior of AUV during LAR process of unmanned surface vehicle (USV).

An Experimental Study on Wave Absorber Performance of Combined Punching Plate in a Two-Dimensional Mini Wave Tank

Hyen-Cheol Jung,Weoncheol Koo 한국해양공학회 2021 韓國海洋工學會誌 Vol.35 No.2

In order to perform a precise wave tank experiment, it is necessary to maintain the incident wave generated by the wavemaker in a steady state and to effectively remove the reflected waves. In this paper, a combined sloping-wall-type punching plate wave absorber was proposed to attenuate reflected waves effectively in a two-dimensional mini wave tank. Using the four-point reflection separation method, the reflected waves were measured to determine the reflection coefficients. Experiments were conducted under various punching plate porosities, sloping plate angles, and incident wave conditions to evaluate the performance of the combined punching plate wave absorber. The most effective wave absorbing performance was achieved when the porosity was 10% and the inclination angle of the punching plate was 18.6° under the present condition. It was also found that the installation of the sloping plate could improve the wave attenuation performance by generating the shoaling effect of the incident wave.