• 한국해안해양공학회지
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• 제14권1호
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• pp.34-40
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• 2002

본 연구에서는 해안선 부근의 장주기파가 해안침식과 관련이 있음에 주목하며 심해파의 특성으로부터 천해역의 장주기파의 파고를 추정하기 위해 파고계 3대를 해안으로부터 외해방향의 해안종단 방향으로 일직선상에 배치하여 현장관측을 실시하고 그 결과를 분석하였다. 아울러, 장주기파의 발생기구에 관한 기존의 이론을 현장관측을 통해 검증하고, 장주기파의 발생기구를 토대로 심해파 제원과 천해역의 장주기 파고와의 관계를 검토하였다. 관측된 장주기파는 기존의 이론과 대체적으로 일치하였으며, 심해파와 장주기파 사이에는 선형적인 대응이있음을 확인하였다. 또한, 장주기파의 공간적·시간적 변화를 추가하기 위하여 각 지점별로 관측된 장주기파를 합성함으로서 장주기파의 파고를 계산하였다. 그 결과, 장주기파와 심해파 사이의 관계는 더욱 뚜렷한 경향을 나타내었으며, 양자로부터 장주기파의 추정식을 도출할 수 있었다. 따라서, 이를 이용함으로서 해당지역의 천해역에 존재하는 장주기파랑의 규모가 심해파랑의 자료로부터 예견될 수 있을 것으로 사료된다.

• Journal of Advanced Marine Engineering and Technology
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• 제35권5호
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• pp.682-689
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• 2011

최근 우리나라 해안지역에서는 너울성 파도(Swell-like wave)에 의한 재해가 빈번하게 발생하고 있다. 이러한 해양 현상은 풍파(wind wave)에 비해 주기가 10초대 이상의 긴 주기를 갖는 특성이 있다. 장주기 파(Long period wave)에 의한 피해를 사전에 예방하기 위해서는 실시간으로 정확하게 관측할 수 있어야 한다. 하지만 현재 파고를 측정하는 기기는 풍파를 관측하는 것을 주 목적으로 하고 있어 장주기 파를 관측할 수가 없다. 따라서 본 연구에서는 GPS를 이용하여 해양에서 실시간으로 운영할 수 있는 장주기 파고 관측시스템을 개발하고자 하는 것이다.

• 한국항해항만학회지
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• 제27권6호
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• pp.677-682
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• 2003

The long-period gravity wave, the wave period from some ten seconds to some minutes, induces not only the big sway of a ship moored and berthed in the harbor due to the horizontal long-distance motion of a water but also strong exfoliated flow and vortices near the harbor entrance. They muse serious problems on the safety navigation of vessels entering and leaving the harbor, but this gravity wave has not been searched sufficiently yet. Then it is quite important to reveal the characteristics of this long-period gravity wave ana to solve various problems induced by this wave. The long-period gravity wave measurement system with arrayed buoys installed the kinematic GPS was already proposed, which provides the precise propagating direction of the long-period gravity wave. In this paper, the observation results of the wave measurement system are shown by the MUSIC method And the propagating wave direction was estimated precisely enough in comparison with other results used other method.

• 한국태양에너지학회 논문집
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• 제38권5호
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• pp.1-9
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• 2018

The purpose of this study is to analyze the urban heat island ultimately by analyzing long-wave radiation which is the dominant factor of night minimum temperature formation. We observed during two months with four elements which is long and short wave radiation, temperature, relative humidity. And we analyzed the correlation between the four factors of long-wave radiation, temperature, cloud form, and cloud amount during the summer two months on the night time. Observations were carried out at two sites in Daegu and nearby. The results are as follows. (1) Long-wave radiation change per $1^{\circ}C$ in summer was larger than winter. (2) Long-wave radiation amount is affected by temperature change when the amount of cloud is small. (3) Low cloud was analyzed to have more influence on long-wave radiation than high cloud.

• 한국태양에너지학회 논문집
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• 제37권6호
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• pp.93-102
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• 2017

Interpretation of relevance between long-wave radiation and meteorological elements is recognized as an essential element for understanding the underlying mechanism of urban thermal environment formation. In this study, we analyzed relation between three elements : long-wave radiation, temperature, and lower-middle class cloudiness. The correlation was analyzed through field observations. The results are as follows. (1) Temperatures and long-wave radiation increased from January to March. This phenomenon has been confirmed in urban and suburban areas. (2) Long-wave radiations showed a tendency to increase clearly with increasing cloudiness.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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• pp.155-162
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• 2001

In this study, it was performed that the seismic response analysis using long period earthquake wave and short period earthquake wave on dynamic behavior of concrete gravity dam. The results showed that if the same magnitude earthquake waves acted on concrete dam, the maximum displacement and stress at dam crest of long period wave(0funato wave) were about 30 % larger than those of short period wave(Hachinohe wave). And the response acceleration of dam crest was amplified about 5 times in long period earthquake wave and about 3 times in short period earthquake wave.

• 한국항해항만학회지
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• 제41권5호
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• pp.329-336
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• 2017

This study suggests a general process of analyzing the mooring and cargo handling limit waves, which is an incident to the new energy port under long wave agitation. To reduce damages of ships and harbor structures due to strong wave responses, it is necessary to predict the change of wave field in the mooring berth to make the proper decision by dock master. The berthing area at a new LNG port in the east coast of Korea in this study is frequently affected by oscillations from waves of 8.5~13s periods in the wintertime. The long period waves give difficulties on port operation by lowering the annual berthing ratio. It needs to find the event waves from the real time offshore wave records, which cause over the mooring limits. For that purpose, the wave records from field measurement and offshore wave buoy were analyzed. From numerical simulation, the response characteristics of long period waves in the berthing area were deduced with or without breakwater expansion plan, analyzing the offshore field wave data collected for two years. Some event wave cases caused over the cargo handling and mooring limits as per the standard Korean port design guideline, and those were used for the decision of port operation by dock master, comparing with the real time offshore wave observations.

• 동력기계공학회지
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• 제13권2호
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• pp.63-70
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• 2009

This paper discusses the influence on long-tenn predictions of the ship response in ocean by using the Global Wave Statistics data, GWS, and wave information from the remote sensing satellites. GWS's standard scatter diagrams of significant wave height and zero-crossing wave period are suggested to be corrected to a round number of 0.01/1000 fitted with a statistical analytic model of the conditional lognormal distribution for zero-crossing wave period. The GEOSAT satellite data are utilized which presented by I. R. Young and G. J. Holland (1996, named as GEOSAT data). At first, qualities of this data are investigated, and statistical characteristic trends are studied by means of applying known probability distribution functions. The wave height data of GEOSAT are compared to the data observed onboard merchant ships, the data observed by measure instrument installed on the ocean-going container ship and so on. To execute a long-tenn prediction of ship response, joint probability functions between wave height and wave period are introduced, therefore long-term statistical predictions are executed by using the functions.

• 한국해양공학회지
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• 제16권2호
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• pp.21-26
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• 2002

In this study, the characteristics of long period waves are analyzed by field observation at Sokcho harbor on the eastern coast of Korea. firstly. the pressure data obtained from field observation are transformed into water surface elevations and the wave by wave analysis is applied to the observed wave data. also, we select long period waves by setting up the range 30-200sec, and suggest the relationship between ordinary waves and long period waves using the concept of the significant wave height. and, we examine the effects oft he long period waves on the rate of the harbor operation. The observation results demonstrate that the long period waves with heights of 1.2-14.6cm and periods of 35.8-162sec exist at Sokcho harbor. also, we found the rates of harbor operation based on long period waves are 61.8%-99.5% lower than the usual rates of 93.8%-100%.

• 한국해양공학회지
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• 제21권5호
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• pp.1-8
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• 2007

A long wave induced by a Gaussian-shape submarine landslide is simulated by a 2D fully nonlinear numerical wave tank (NWT). The NWT is based on the boundary element method and the mixed Eulerian/Lagrangian approach. Using the NWT, physical characteristics of land-slide tsunami, including wave generation, propagation, particle kinematics, hydrodynamic pressure, run-up and depression, are simulated for the early stage of long wave generation and propagation. Various sliding mass heights are applied to the developed model for a systematic sensitivity analysis. In particular, the fully nonlinear NWT results are compared with linear results (exact body-boundary conditions with linear free-surface conditions) to identify the nonlinear effects in the respective cases.