• Journal of Advanced Research in Ocean Engineering
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• 제1권1호
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• pp.25-35
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• 2015

This study presents the analysis of relationship between ship speed and local ice load on the Korean Icebreaker ARAON. The relationship curves were made from the data obtained at two areas: the Arctic and the Antarctic; and for two operation condition: the icebreaking condition in sea ice trial and general operation in ice covered sea. The strain data were converted to the equivalent stress value, and the influence of ship speed on the local ice load was analyzed and compared each other. These analysis results are useful in working on a statistically valid hull design approach.

• 한국항해항만학회지
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• 제37권2호
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• pp.143-148
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• 2013

본 연구의 목적은 빙해역을 운항하는 선박의 쇄빙시 깨진 해빙에 의해 선수부 좌현 외판에 작용하는 국부 빙하중을 계측한 신호의 특성을 조사하는 것이다. 한국 최초의 쇄빙연구선인 아라온호를 이용하여 2010년 8월초 북극해에서 실선 시험을 수행하여 선수부에 설치된 변형률 게이지로부터 국부적인 빙하중에 의한 신호를 계측하였다. 국부적인 빙하중에 의한 구조 응답 특성을 반영한 계측 신호는 전형적인 유체 충격압에 대한 하중-시간 이력과 다소 다른 특성을 갖는 것도 있음이 파악되었다. 본 연구에서는 계측 신호에 대한 시간 이력을 분석하고, 무차원화된 특성값들로 나타내었다.

• 대한조선학회논문집
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• 제45권2호
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• pp.175-185
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• 2008

One of the concerns that arise during navigation in ice-covered waters is the magnitude of ice loads encountered by ships. However, the accurate estimation of ice loads still remains as a rather difficult task in the design of icebreaking vessels. This paper focuses on the development of simple ice load prediction formulas for the icebreaking cargo vessels. The maximum ice loads are expected from unbroken ice sheet and these loads are most likely to be concentrated at the bow area. Published ice load data for icebreaking vessels, from the model tests and also from full-scale sea trials, are collected and then several ice load prediction formulas are compared with these data. Finally, based on collected data, a semi-empirical ice load prediction formula is recommended for the icebreaking cargo vessels.

• 한국해양공학회지
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• 제27권5호
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• pp.82-87
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• 2013

The icebreaking research vessel ARAON conducted her second ice trial in the Arctic Ocean during the summer season of 2010. During this voyage, the local ice loads acting on the bow of the port side were measured using 14 strain gauges. The measurement was carried out during icebreaking while measuring the thickness of the ice every 10 m. The obtained strain data were converted to the equivalent stress values, and the effects of the ship speed and ice thickness on the ice load were investigated. As a result, it was found that a faster speed produced a larger stress, according to the variation in the peak values below an ice thickness condition of 1.5 m. Meanwhile, the effect of the ice thickness on the ice load was not clear.

• 한국해양공학회지
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• 제19권6호통권67호
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• pp.50-57
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• 2005

Ice resistance on ice-transiting vessels is one of th￡ important issues concerning th￡ design of ships with ice classes. In this study, th￡ development of GUI software for estimation of ice resistance on ice-transiting vessels is discussed. lee resistance estimation equations, based on model tests and full-scale sea trial data from many previous research articles, are studied in conjunction with two ship categories i.e., ,icebreakers/supply/tug vessels and ice-strengthened cargo vessels. lee resistance estimation equations are summarized in common format and are compared with each other. The GUI software 'Ice View,' written in MS Visual Basic language, can calculate ice resistances according to varying ice thickness and ship speed. The software can provide the calculated results, with suitable tables and graphs, for easy comparison of each ice resistance estimation equation.

• 대한조선학회논문집
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• 제51권2호
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• pp.107-113
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• 2014

The icebreaking research vessel, ARAON had her second ice trial in the Arctic Sea from 16th July to 12th August 2010. During the voyage, the local ice loads acting on the bow of port side were measured from 14 strain gauges. The measurements were also carried out in ice waters with various ice concentration ratio as well as the icebreaking performance tests. In this study, the ice loads measured during the 'general' operation in ice waters were analyzed. As a first step, the relationship between the location of strain gauges and the ice loads were investigated, and then the possibility for observation of higher ice loads was estimated based on the probability density function. The relationship between the ship speed and the ice load was also investigated. 718 peak stresses data higher than 20 MPa obtained from strain gauges array attached in longitudinally and vertically was analyzed. In general, the ice load increases as the ship speed increases in the low ship speed range, and ice load decreases as the ship speed is greater than a certain speed.

• 한국해양공학회지
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• 제27권5호
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• pp.88-92
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• 2013

The icebreaking research vessel (IBRV) ARAON had her second ice trial in the Arctic Ocean in the summer season of 2010. During the voyage, the local ice loads acting on the bow of the port side were measured using 14 strain gauges. These measurements were carried out in three icebreaking performance tests. To convert the measured strains into the local ice pressures, a finite element model of the instrumented area was developed. The influence coefficient method (ICM), which uses the influence coefficient from the finite element model, and the direct method, which uses the measured strain, were selected as the conversion methods. As a result, the maximum measured pressure was 1.236MPa, and the average difference between ICM and the direct method was about 5% for an area of $0.2m^2$. The pressure-area relationship of the measurement falls below the range of the existing pressure-area curve, which is due to the low ice strength of melted ice in the summer.

• 대한조선학회논문집
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• 제43권2호
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• pp.147-155
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• 2006

Ice resistance estimation equations based on model tests and full-scale sea trial data from many previous research articles are studied. Measured ice resistance data and its empirical/semi-empirical estimation equations are summarized in common format and are compared with each other, considering three ship categories, i.e, icebreakers, tug/supply vessels, ice-strengthened cargo vessels. The most suitable estimation methods or prediction equations are recommended based on this ice resistance data analysis.

• 대한조선학회논문집
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• 제45권5호
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• pp.513-522
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• 2008

In this paper, one of the widely-used ice resistance prediction methods, introduced by Spencer(1992) of the Institute for Ocean Technology, Canada, is reviewed. Spencer's component-based scaling system for ship-ice model tests is analysed to estimate the ice resistance of various types of icebreaking vessels (Canadian MV Arctic, Terry Fox, R-Class icebreaker, US icebreakers Polar Star and Healy, Russian SA-15 cargo ships, Japanese PM Teshio and a model ship). The general form and the non-dimensional coefficients in ice resistance prediction formula are obtained using the published ice model test and full-scale sea trial data. The applicability of Spencer's method on R-Class icebreaker is discussed to estimate ice resistance for the larger icebreaking cargo vessels. Additional parameters to account for the difference in hull forms of icebreakers and cargo vessels are recommended to be included in the Spencer's original ice resistance prediction formula.

• 천문학회보
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• 제37권1호
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• pp.76.2-76.2
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• 2012

The understanding spectral characterization of possible earth-like extra solar planets has generated wide interested in astronomy and space science. The technical central issue in observation of exoplanet is deconvolution of the temporally and disk-averaged spectra of the exoplanets. The earth model based on atmospheric radiative transfer method has been studied in recent years for solutions of characterization of earthlike exoplanet. In this study, we report on the current progress of the new method of 3D earth model as a habitable exoplanet. The computational model has 3 components 1) the sun model, 2) an integrated earth BRDF (Bi-directional Reflectance Distribution Function) model (Atmosphere, Land and Ocean) and 3) instrument model combined in ray tracing computation. The ray characteristics such as radiative power and direction are altered as they experience reflection, refraction, transmission, absorption and scattering from encountering with each all of optical surfaces. The Land BRDF characteristics are defined by the semi-empirical "parametric-kernel-method" from POLDER missions from CNES. The ocean BRDF is defined for sea-ice cap structure and for the sea water optical model, considering sun-glint scattering. The input cloud-free atmosphere model consists of 1 layers with vertical profiles of absorption and aerosol scattering combined Rayleigh scattering and its input characteristics using the NEWS product in NASA data and spectral SMARTS from NREL and 6SV from Vermote E. The trial simulation runs result in phase dependent disk-averaged spectra and light-curves of a virtual exoplanet using 3D earth model.