• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.34-34
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• 2023

The Chah-Nimeh reservoirs, which are a sort of natural lakes located in the border of Iran and Afghanistan, are the main drinking and agricultural water resources of Sistan arid region. Considering the occurrence of intense seasonal wind, locally known as levar wind, this study aims to explore the possibility to provide a TSM (Total Suspended Matter) monitoring model of Chah-Nimeh reservoirs using multi-temporal satellite images and in-situ wind speed data. The results show that a strong correlation between TSM concentration and wind speed are present. The developed empirical model indicated high performance in retrieving spatiotemporal distribution of the TSM concentration with R²=0.98 and RMSE=0.92g/m³. Following this observation, we also consider a machine learning-based model to predicts the average TSM using only wind speed. We connect our in-situ wind speed data to the TSM data generated from the inversion of multi-temporal satellite imagery to train a neural network based mode l(Wind2TSM-Net). Examining Wind2TSM-Net model indicates this model can retrieve the TSM accurately utilizing only wind speed (R²=0.88 and RMSE=1.97g/m³). Moreover, this results of this study show tha the TSM concentration can be estimated using only in situ wind speed data independent of the satellite images. Specifically, such model can supply a temporally persistent means of monitoring TSM that is not limited by the temporal resolution of imagery or the cloud cover problem in the optical remote sensing.

• Wind and Structures
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• 제10권6호
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• pp.495-510
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• 2007

Wind pressure data have been collected on the tiled roof of a full-scale test house at Silsoe in the UK. The tiled roof was of conventional UK construction with a batten-space and bitumen-felt underlay beneath the interlocking concrete tiles. Pressures were monitored on the outer surface of selected tiles, at several locations within the batten-space, and beneath the underlay. Data were collected both with and without ventilator tiles installed on the roof. Little information appears to exist on the share of wind load between tiles and underlays which creates uncertainty in the design of both components. The present study has found that for the critical design case of maximum uplifts it would be appropriate to assign 85% of the net roof load to the tiles and 15% to the underlay when an internal pressure coefficient of -0.3 is used, and to assign 60% to the tiles and 50% to the underlay when an internal pressure coefficient of +0.2 is assumed (an element of design conservatism is inherent in the apparent 110% net loading indicated by the latter pair of percentage values). These findings indicate that compared with loads implied by BS 6399-2, UK design loads for underlay are currently conservative by 25% whilst tile loads are unconservative by around 20% in ridge and general regions and by around 45% in edge regions on average over roof slopes of $15^{\circ}-60^{\circ}$.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3599-3616
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• 2023

After a nuclear power plant (NPP) accident, it would be helpful to predict the movement of the radioactive plume emitted from the NPP as accurately as possible to protect the nearby population. Radioactive plumes are mainly affected by wind direction and speed. Since it is difficult to identify the wind direction and speed immediately after the accident, a good understanding of the historical wind data could save many lives and ensure smoother evacuation procedures. In this study, wind data for the past 10 years are analyzed for the five NPPs in the Republic of Korea (ROK). The analyzed data include wind direction and wind speed from 2012 to 2021. In particular, the characteristics of the wind field blowing from the NPPs to the nearest densely populated regions are examined. Finally, suggestions to improve evacuation plans are made.

• 수산해양기술연구
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• 제48권1호
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• pp.59-71
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• 2012

In order to elucidate the mechanism of fishing condition variation of anchovy in the set net fisheries of Anggang Bay, the monthly catch of anchovy was analyzed and examined based on the data acquired from 2006 to 2010 in 13 different fishing grounds. Anchovy consistently appeared from April to December and reached the production of 840 to 1,424 t (average : 1,228 t), with a big annual variation. However, anchovy production in this area accounts for approximately 75% of the production by set net in Anggang Bay whereas it holds 6.8% of the nationwide production (=18,034 t) by set net. The school of anchovy starts to appear in April at the west mouth of the bay and move north-eastward. Afterward, having three of clockwise turns in the middle of the bay, they scatter to swim into the deep place of the bay and finally go out to turn back to their coming way. These behaviors of anchovy are likely related to thermal fronts as well as distributions of food. The production of anchovy (y, kg) relied greatly on frequencies of effective northeasterly ($x_1$) or northwesterly ($x_2$) wind (${\leq}$3.5m/s) which blow between April and June. Their relationships are as follows: $y=1086.27+21.499x_1-15.16x_2$ (r=0.901). Consequently, we concluded that the northeasterly wind, which appears in the breeding season of spring, played a role to retard the movement of anchovy school to the eastern sea, while the northwesterly wind inhibits the invasion of anchovy school into the bay.

• 전기학회논문지
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• 제64권1호
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• pp.35-40
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• 2015

This paper presents the optimal network configuration for electric stations using HOMER software. For the given data such as annual average wind speed and grid costs, this software calculates the NPC(Net Present Cost), operating cost and COE(Cost of Energy). Based on these simulation results, it is possible to find the optimal network configuration for electric stations depending on the grid cost and average wind speed. When the rising grid cost is considered, it is essential to use grid and renewable energy together. Depending on the increase of the grid cost, NPC of the configuration using renewable energy and grid can be gradually getting smaller than NPC of the configuration using only grid.

• Ocean Science Journal
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• 제43권3호
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• pp.147-152
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• 2008

The seasonal variability of sonic layer depth (SLD) in the central Arabian Sea (CAS) (0 to $25^{\circ}N$ and $62-66^{\circ}E$) was studied using the temperature and salinity (T/S) profiles from Argo floats for the years 2002-2006. The atmospheric forcing responsible for the observed changes was explored using the meteorological data from NCEP/NCAR and Quickscat winds. SLD was obtained from sound velocity profiles computed from T/S data. Net heat flux and wind forcing regulated SLD in the CAS. Up-welling and down-welling (Ekman dynamics) associated with the Findlater Jet controlled SLD during the summer monsoon. While in winter monsoon, cooling and convective mixing regulated SLD in the study region. Weak winds, high insolation and positive net heat flux lead to the formation of thin, warm and stratified sonic layer during pre and post summer monsoon periods, respectively.

• Nuclear Engineering and Technology
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• 제51권2호
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• pp.607-617
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• 2019

Global warming and climate change are increasing the intensity of typhoons and hurricanes and thus increasing the risk effects of typhoon and hurricane hazards on nuclear power plants (NPPs). To reflect these changes, a new NPP should be designed to endure design-basis hurricane wind speeds corresponding to an exceedance frequency of $10^{-7}/yr$. However, the short typhoon and hurricane observation records and uncertainties included in the inputs for an estimation cause significant uncertainty in the estimated wind speeds for return periods of longer than 100,000 years. A logic-tree framework is introduced to handle the epistemic uncertainty when estimating wind speeds. Three key parameters of a typhoon wind field model, i.e., the central pressure difference, pressure profile parameter, and radius to maximum wind, are used for constructing logic tree branches. The wind speeds of the simulated typhoons and the probable maximum wind speeds are estimated using Monte Carlo simulations, and wind hazard curves are derived as a function of the annual exceedance probability or return period. A logic tree decreases the epistemic uncertainty included in the wind intensity models and provides reasonably acceptable wind speeds.

• 한국농공학회논문집
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• 제63권5호
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• pp.63-71
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• 2021

Windbreak forests, which have a windproof effect against strong winds, are known to be effective in reducing the spread of odors and dust emitted from livestock farms. The effect of reducing the spread of odors and dust can be estimated through numerical models such as computational fluid dynamics, which require aerodynamic coefficients of the windbreaks for accurate prediction of their performance. In this study, we aimed to evaluate the aerodynamic coefficients, Co, C₁, C₂, and α, of two windbreaks, Thuja occidentalis and a mesh net, through wind tunnel experiments. The aerodynamic coefficients were derived by the relation between the incoming wind speed and the pressure loss due to the windbreaks which was measured by differential pressure sensors. In order to estimate the change in the aerodynamic coefficient concerning various leaf density, the experiments were conducted repeatedly by removing the leaves gradually in various stages. The results showed that the power law regression model more suitable for coefficient evaluation compared to the Darcy-Forchheimer model.

• 환경영향평가
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• 제23권1호
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• pp.11-17
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• 2014

Since the Renewable Portfolio Standard (RPS) would be started in 2012, the use of renewable energy should be 11% of total energy use including bio-fuel in 2030. The economic efficiency for renewable energy in B power plant was considered with the bio-diesel, wind power and solar power. The Net Present Value (NPV) and Benefit/Cost Ratio(BC) were used for the economic efficiency with the cost and benefit analysis. In case of bio-diesel, the cost resulted from the fuel conversion and the benefit would be created with trade and environmental improvement. With regard to wind power and solar power, the construction cost would be required and benefit factors would be same as the bio-diesel. The wind power was the best of economic efficiency of renewable energy as the results of NPV and BC ratio. Whereas, the market of wind power was very popular and the techniques of wind power has been developing rapidly.

• 해양환경안전학회지
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• 제29권2호
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• pp.127-138
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• 2023

국제사회는 글로벌 기후위기 극복을 위해 2050년까지 탄소중립(Net Zero)을 목표로 다양한 탈탄소 에너지원 개발을 지속하고 있다. 우리 정부에서도 '재생에너지 3020' 정책을 수립하고 태양광이나 풍력을 이용한 에너지 개발계획을 추진함에 따라 해상 풍력발전단지와 같이 연안해역에서 기존에는 볼 수 없었던 대규모 해양개발사업이 추진되고 있다. 해양시설물은 선박의 입장에서 볼 때는 항행 장애물의 일종이며, 해양시설물 설치에 따라 좁아진 수역에서 선박 간 충돌사고 발생 또는 선박과 해양시설물의 접촉사고 발생시 환경오염 및 인명피해 등의 발생이 우려된다. 이에 국내외의 해상풍력발전단지 개발계획을 살펴보고 풍력단지에서 선박의 안전한 통항을 보장하기 위한 제도적 장치가 완비되어 있는지 분석하였으며, 해외의 입법 사례와 국내 법규를 비교하여 법적 사각지대를 해소하기 위한 새로운 법령안을 제안함으로써 대한민국의 관할해역에서 해양시설물의 안전한 운영과 선박의 안전한 통항을 기대하였다.