• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.667-673
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• 2019

Global warming may accelerate climate change and may increase disaster caused by strong winds. This research studied a method for a nonstationary frequency analysis considering the linear trend over time. The Bayesian method was used to estimate the posterior distribution of the parameters for the extreme value distribution of the annual maximum wind speed at Jeju Airport. The nonstationary frequency analysis was performed based on the Monte Carlo Markov Chain simulation and the Gibbs sampling. The estimated wind speeds by nonstationary frequency analysis was larger than those by stationary analysis. The conventional frequency analysis procedure assuming stationarity is likely to underestimate the future design wind speed in the region where statistically significant trend exists.

• Journal of the Korean association of regional geographers
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• v.22 no.4
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• pp.809-825
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• 2016

This study aims to review the existing forms and farmers'perception of the agricultural dry stonewalls under agricultural environment, based on the case of Hado-ri, Gujwa-eup, Jeju Province. The study results are as follows: First, agricultural dry stonewalls in Hado-ri are most external walls, many of which are curvy. Concrete walls have recently shown up to enclose fields. Second, the height of agricultural dry stonewalls varies according to the location, and their length was calculated 16.514km(two farming region) based on a field survey and numerical cadastral maps. Third, farmers in Hado-ri perceive a great need for agricultural dry stonewalls. This means that agricultural dry stonewalls have a sustainable value despite rapid social change. Fourth, the methods for the sustainable preservation of agricultural dry stonewalls involve improving eco-friendly agricultural environment for the stonewalls, building database by village about them, carrying out their transformation and building according to promulgated ordinances, promoting the value of the stonewalls to Jeju citizens, and educating them to perceive the value of the stonewalls.

• Journal of The Korean Association For Science Education
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• v.27 no.9
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• pp.848-853
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• 2007

The purpose of this study was to investigate the relationships among scientifically gifted students' science related attitudes, learning motivation and learning strategy. Subjects were 135 middle school students enrolled at a Center for Science Gifted and Talented Education. There was no difference among talented divisions according to science related attitudes. But the score of the female students were higher than that of the male in learning motivation and learning strategy. Some significant correlation coefficients were between learning motivation and learning strategy. Also significant correlation coefficients were among 'career interest in science' domain, 'leisure interest in science' and 'social implication of science.'

• Journal of the Korean earth science society
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• v.21 no.1
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• pp.81-92
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• 2000

The purpose of this study is to elucidate the characteristic of this study is of attitudinal variation of water quality for nine representative springs in the Halla mountain region. The evolutional processes of the spring water also have been studied. Results of hydrogeochemical analyses show that Gwaneumsa spring is very high in pH. The spring waters from Yungsil, Namguksunwon, Sungpanark Oremok and Gwaneumsa which springs situated lower than 1000m in altitude are relatively high concentrations in chloride, sulphate, nitrate nitrogen and sodium ions, indicating that they are affected by surrounding pollution sources. The concentrations of bicarbonate, sulphate and hydrogen ions in spring waters increase when the precipitation increases, whereas the concentrations of nitrate nitrogen, chloride and calcium ions decrease with increasing amounts of precipitation. The magnesium, sodium and electrical conductivity are nearly independent of the precipitation. The spring waters in the Halla mountain region belong to the groups of sodium or potassium type and bicarbonate type, except the Baegrogdam and Wiseorm spring water.

• The Korean Journal of Malacology
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• v.10 no.2
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• pp.10-23
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• 1994

패류화석은 지구를 이루는 퇴적암 중 석회암을 이루고 있는 주요 구성원 중의 하나이다. 지난 20년간 지질학자 및 해양학자들은 주로 심해에 쌓여 있는 퇴적물 중의 미화석(microfossil)을 이용하여 과거의 기후 및 해양의조건을 규명하기 위하여 많은 노력을 하여왔다. 그 결과로서 지질학적 시대 중 중생대 이후로부터 신생대에 이르기까지 지구 전반에 영향을 주었던 고기후에 대한 많은 정보가 얻어졌다. 또한 일부 학자들에 의하여 천해에 서식하였던 여러 화석들의 생태와 지화학적 분석(geochemical analysis)을 통하여 지엽적인 고기후(paleoclimate) 및 고해양학적(paleoceanographic)이해도 증진되어 온 것이 사실이다. 천해에 서식하고 있는 석회질 골격(calcareous skeleton)을 만드는 생물종들은 주로 생화확적인 작용을 통하여 아라고나이트와 방해석이라는 탄산염 광물을 침전시킨다. 특히 이 중에서 아라고나이트라는 광물은 불안정하여 속성작용 (퇴적물이 쌓인 후 거치는 물리, 화학적 작용)동안에 방해석으로 변하게 된다. 따라서 특이한 속성환경의 조건에 의해 아라고나이트로 보존되어 있는 패류를 제외하고는 주로 방해석으로 이루어진 화석의 분석을 통하여 고환경 복원을 위한 여러 정보를 얻을 수 있다. 이를 근거로 하여 분석 대상이 주로 된 것은 완족류나 방해석으로 이루어진 이매패류(e.g., 굴등)이었다.우리나라에서는 최근에 이르러서야 패류 화석의 지화학적 분석을 통하여 고해양학적 연구가 수행되기 시작하였다. 신생대 제 3기 마이오세에 해당하는 포항 부근에서 발견되는 연체동물 화석들은 변질이 안된 상태로서 우리에게 매우 귀중한 고해양학적 정보를 제공한다. 과거에 생물이 자랐던 성장 온도는 산소 동위원소의 비를 측정하여 구할 수 있는데 그결과에 의하면 해수의 온도가 현재보다 약간 높았음을 지시한다. 제주도 내의 서귀포 부근에서는 현재 천연기념물로 지정되어 있는 서귀포층내에서 많은 화석들이 산출되고 있다. 이 시대는 빙하기와 간빙기가 교호하던 시대로서, 분석 결과에 의하면 서귀포층이 쌓일 당시에 우리 나라는 빙하기의 영향을 받았던 것으로 생각된다.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.197-202
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• 2005

The electromagnetic signals associated with the seismic activity in the south-east offshore of Kii peninsula, Japan, were clearly recorded at the MT sites in Jeju island, Korea. In this research, we have identified the co-seismic electromagnetic signals associated with the seismic activity and have analyzed the characteristics of significant electromagnetic variations. The analysis of phase velocity, power spectral density, MT impedance and polarization direction shows that the significant earthquake signals have the frequency band of about 0.05 to 0.5 Hz and that the sources of electromagnetic field are local effects of passing seismic waves. The simple approximation using electrokinetic effect successfully explains the co-seismic EM signals coincides with measured data but cannot explain the localities of electromagnetic variations.

• Journal of the Korean earth science society
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• v.34 no.7
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• pp.633-644
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• 2013

This study evaluates wind farm efficiency at Haengwon in Jeju Island. The actual energy production at Haengwon wind farm is compared with the estimated energy production based on Korean wind map which is developed at the National Institute of Meteorological Research/KMA. The validation of wind map at Gujwa located near the Haengwon wind farm shows that the wind speed is overestimated. The diurnal variation of wind speed shows a maximum value in the afternoon due to the effect of sea-land breeze. The ratio of the actual energy production at Haengwon wind farm and the estimated energy production based on the Korean wind map is 24.8%, while the distribution of energy frequency is similar each other. The difference of energy production is caused by mechanical error of the turbine and the overestimation of the simulated wind map. This study will contribute to the repowering of turbines for improving the efficiency of wind farm in the future.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.37-52
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• 2013

Prior to full-scale implementation of smart grid, the Korean government is conducting a smart grid testbed in Jeju island. However, the participants of the ongoing program are skeptical about the success of the expansion of smart grid. The concern rises from various reasons; the limits of the Korean electricity market mainly led by both the government and KEPCO, high stability and reliability of the existing electricity grid, insufficient utilization of renewable energy, and public fear of raised electricity bills. Five key issues in regards to facilitating the Korean smart grid market are extracted and evaluated. The issues are conflict of interest among participants, the effect of introducing real-time pricing, lack of customer participation of demand response, and absence of business models.

• Journal of the Korean earth science society
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• v.44 no.6
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• pp.533-539
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• 2023

This article reviews a few academic discussions in our geological society. The author presents his opinion on the discussions regarding the ages of the Okcheon Group, Myogog Formation, and hominid footprints of the Jeju Island, as well as on the inaccurate reportage in mass media. The academia advances via healthy debates and discussions. The arguments for and against Darwin's "Origin of Species" and scientific debates regarding Wegener's "Continental Drift Hypothesis" are well known. In academic debates or discussions, authority should not be involved in any form. Academic research should be conducted based on scientific principles and evidence-free of personal preferences or other nonacademic factors. Opponents should challenge with scientific approaches, suggesting alternatives based on science. Opposition without scientific basis is not productive in conducting academic research in search of scientific truth. Often, the news media delivers inaccurate information to the public-intentionally or unintentionally. There must be a mechanism to immediately identify and rectify inaccurate, false, or fake information for the benefit of the public and the credibility of the news media.

• Economic and Environmental Geology
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• v.38 no.4 s.173
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• pp.435-450
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• 2005

The purpose of the study is to analyze the hydrogeochemical characteristics by multivariate statistical method, to interpret the hydrogeochemical processes for the new variables calculated from principal components analysis (PCA), and to infer the groundwater flow and circulation mechanism by applying the geostatistical methods for each element and principal component. Chloride and nitrate are the most influencing components for groundwater quality, and the contents of $NO_3$ increased by the input of agricultural activities show the largest variation. The results of PCA, a multivariate statistical method, show that the first three principal components explain $73.9\%$ of the total variance. PC1 indicates the increase of dissolved ions, PC2 is related with the dissolution of carbonate minerals and nitrate contamination, and PC3 shows the effect of cation exchange process and silicate mineral dissolution. From the results of experimental semivariogram, the components of groundwater are divided into two groups: one group includes electrical conductivity (EC), Cl, Na, and $NO_3$, and the other includes $HCO_3,\;SiO_2,$ Ca, and Sr. The results for spatial distribution of groundwater components showed that EC, Cl, and Na increased with approaching the coastal line and nitrate has close relationship with the presence of agricultural land. These components are also correlated with the topographic features reflecting the groundwater recharge effect. The kriging analysis by using principal components shows that PC 1 has the different spatial distribution of Cl, Na, and EC, possibly due to the influence of pH, Ca, Sr, and $HCO_3$ for PC1. It was considered that the linear anomaly zone of PC2 in western area was caused by the dissolution of carbonate mineral. Consequently, the application of multivariate and geostatistical methods for groundwater in the study area is very useful for determining the quantitative analysis of water quality data and the characteristics of spatial distribution.