• Journal of Wetlands Research
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• v.21 no.spc
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• pp.61-68
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• 2019

Recently, climate indices represented by quantifying atmospheric-ocean circulation patterns have been widely used to predict hydrologic variables for considering long-term climate variability. Hydrologic forecasting models based on artificial neural networks have been developed to provide accurate and stable forecasting performance. Forecasts of hydrologic variables considering climate variability can be effectively used for long-term management of water resources and environmental preservation. Therefore, identifying significant indicators for hydrologic variables and applying forecasting models still remains as a challenge. In this study, we selected representative climate indices that have significant relationships with dam inflow time series in the Han-River basin, South Korea for applying the dam inflow forecasting model. For this purpose, the ensemble empirical mode decomposition(EEMD) method was used to identify a significance between dam inflow and climate indices and an artificial neural network(ANN) ensemble model was applied to overcome the limitation of a single ANN model. As a result, the forecasting performances showed that the mean correlation coefficient of the five dams in the training period is 0.88, and the test period is 0.68. It can be expected to come out various applications using the relationship between hydrologic variables and climate variability in South Korea.

• Journal of Navigation and Port Research
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• v.29 no.10 s.106
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• pp.853-858
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• 2005

Recently, various novel numerical models based on Navier-Stokes equation have been developed for calculating wave motions in the sea with coastal or ocean structures. Among those models, Volume Of Fluid (VOF) method might be the most popular one, and it has been used for numerical simulations of wave motions including complicated phenomena of wave breakings. VOF method, however, needs enormous computation time and large computational storage memories in general, thus it is practically difficult to use this method for calculations in the case of random waves because long and stable computation (e.g for more than 100 significant wave periods) is required to obtain statistically meaningful results. On the other hand if the wave motion is potential motion, Boundary Element Method (BEM), which is a much faster and more accurate method than VOF method, can be effectively used. The aim of this study is to develop a new efficient model applicable to calculations of wave motion and/or wave-structure interactions under random waves. To achieve this, a strictly combined BEM-VOF model has been developed by making the best use of both methods' merits; VOF method is used in a restricted fluid domain around a structure where complicated phenomena of wave breakings may exist, and BEM is used in the other domains far from the disturbance where the wave motion may be assumed to be potential. The verification of the model was performed with numerical results for Stokes' 5th order wave propagation and a random wave propagation.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.5
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• pp.91-100
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• 2011

This study aimed at the identity of the landscape architectural award, which is the highest authority award system in landscape architecture; the establishment of cooperation between the landscape architecture and urban public sector, which deals with infrastructure is significantly requested nowadays. The identity characteristic of a detailed concept which configures the sameness in the shape of inner self-cognition and individuality as external and correlative cognition are utilized as the research methodology, and the findings are summarized as follows. The Korean Landscape Architectural Award holds an internal value as the only award in landscape architecture that is granted municipalities and public agencies. However, when it is compared with several correlated award systems, the vulnerable sides such as short origin and partly limping in terms of sustainability, the possibilities of losing the interest in the public sector due to management's reform program and insufficient participants and responses regarding social authority have been found. In addition, according to the today's paradigm tha taims for green cities, the aspect that shares the large portion with the values set by detailed categories of city planning that enforces metropolis awards is also in the spotlight. Hence, the landscape architectural award should construct specialization and development strategies by strengthening the superiority compared with the city award in the field of city planning. In other words, the Ministry of Land, not limited to the systematic cooperation with various administrative areas will be strengthened and it will communicate with the aspect that reinforces characters as an academic and practical area that covers various districts and disciplines. Thus, the identity is directly connected to the landscape architectural award's competitive reinforcement as a detailed characteristic variously combined, and it requires huge interest and discussions regarding internal and external landscape architecture areas and the democratic public discussion process.

• Journal of Korean Society of Steel Construction
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• v.25 no.3
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• pp.307-320
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• 2013

This paper proposes a new hybrid support structure by the driven piles which removes disadvantages of the existing type of support structure for offshore wind turbines. The hybrid type of support structure is combined with concrete cone and steel shaft, and is supported not only by gravity type foundations but also by driven piles. For three dimensional analysis of the huge and thick concrete structure, a solid-shell element that is capable of exact modeling and node interpolations of stresses is developed. By applying wave theory of stream function and solid-shell element in XSEA simulation software for fixed offshore wind turbines, a quasi-static analysis and natural frequency analysis of proposed support structure are performed with the environmental condition on Southwest Coast in Korea. In the result, lateral displacement is not exceed allowable displacement and a superiority of dynamic behavior of new hybrid support structure is validated by natural frequency analysis. Consequently, the hybrid support structure presented in this study has a structural stability enough to be applied on real-site condition in Korea. The optimized structures based on the preliminary design concept resulted in an efficient structure, which reasonably reduces fabrication costs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.1
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• pp.68-80
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• 1984

Garolim Bay is not only important fishing ground but also expected area for the tidal power plant. The construction and operation of tidal power plant will make change the ecosystem of this bay. Therefore, the actual fisheries stocks should be precisely understood for the effect estimation and overall utilization of the bay after the construction of the tidal power plant. During the study period from January through December in 1981, forty-six adult fishes species, 3 species of fish egg and 25 fishes larvae species have occurred in the bay. Considering the result on monthly distribution of eggs and larvae, the inner area of the bay seems to be important as nursing ground of larvae spawned at the outside bay in winter, e. g., Ammodytes personatus, and Enedrias sp. This inner bay is also major spawning ground for many species spawning in spring and summer, e. g., Gobiidae, Konosirus punctatus, Engraulis japonica, etc. Taking into consideration the annual mean production for three years($1978{\sim}1980$), there are two major fishing seasons. The one is in May-June for Enedrias larvae stock, and the another in October-November for big eyed herring stock. For the mariculture stocks, short necked clam, oyster and laver are important species. After construction of the tidal power plant, the migratory species, i. e., larvae of Enedrias and Ammodytes personatus, Mugil cephalus, Konosirus punctatus, etc. will be directly damaged by the interuption of migration route. On the otter hand, the change of physico-chemical factors of seawater will also affect the ecosystem of the bay. Consequently, for the overall utilization of the bay after construction, the actual ecosystem including the fisheries stocks, must bs precisely revealed, and the mechanical designs, e. g., sluice position and its demension, should be also considered with these biological characters of the bay.

• Strategy21
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• s.42
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• pp.114-153
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• 2017

고도화 및 가시화되고 있는 북한의 '잠수함발사탄도미사일(SLBM: Submarine Launched Ballistic Missile)'위협에 대응하기 위한 효과적인 전략수단으로써 핵추진잠수함의 필요성에 대한 국민적 관심이 고조되고 있다. 핵추진잠수함의 전략적 가치에 대한 논의가 활발히 진행되고 있는 가운데, 주변국과의 갈등과 국제사회의 비핵화 규범의 미 준수 논란 등 핵추진잠수함 확보과정에서 야기될 수 있는 대·내외의 정치·외교적 파장에 대한 우려의 목소리 또한 높아지고 있다. 그러나, 핵추진잠수함의 필요성 및 확보와 관련한 지금까지의 대부분의 논의들은 한국의 '내부적 논의(Just our own scenario)'에 그치는 한계를 보이고 있다. 전략무기체계로써의 상징성과 그에 따르는 대외적 민감성을 고려 시 일방적이고 독자적인 핵추진잠수함 확보노력은 과정상의 시행착오와 불확실성을 더욱 가중시켜 정책적 실패로 귀결될 수 있는 위험성을 내포하고 있다. 특히, 한반도 평화와 아태지역의 안전보장이라는 공동의 전략적 목표를 공유하고 있는 동맹국인 미국의 공감대와 지지가 뒷받침되지 않은 독자적인 핵추진잠수함 확보노력은 큰 난항이 예상되며 자칫 서로간의 '전략적 신뢰(Strategic Trust)'를 무너뜨려 '한미동맹의 결속력(Alliance Cohesion)'을 약화시키는 요인으로 작용할 수 있다. 미국의 동의와 지지에 기반한 핵추진잠수함 확보를 위해서는 한국의 핵추진잠수함 확보가 동맹의 전략목표 및 미국의 전략적 이해관계에 미칠 수 있는 긍정적, 부정적 효과에 대한 충분한 검토와 논의가 선행되어야 한다. 한미동맹의 공동의 전략목표와 미국의 전략적 이익에 상충하는 한국의 핵추진잠수함 확보시도는 성공 가능성이 낮기 때문이다. 본 연구에서는 현실화되고 있는 북한의 핵위협에 대응하고 지역안전보장에 기여할 수 있는 미국과의 연합방위력 증강차원에서의 한국의 핵추진잠수함의 전략적 효용성을 분석하였다. 더불어, 한국의 핵추진잠수함 확보과정에서 야기될 수 있는 대·내외의 기술적, 정치·외교적 사안들을 살펴본 후 한미동맹 차원에서의 정책적 해결방안을 제시하였다. 연구목적을 위해 유사한 역사적 사례연구를 통해 교훈을 도출하였으며, 미국 오바마 1기 행정부에서 미국의 아태지역 및 대북정책을 주도한 전 미국 국무부부장관 제임스 스타인버그(James Steinberg) 및 여러 미국 내 한반도 전문가들의 의견을 수렴하였다. 본 연구가 한국의 핵잠수함 확보를 위한 한미간 발전적 논의의 시발점이 되기를 기대한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1151-1159
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• 2014

In this study, two global simple indices are used to investigate climate variability and change in observations. Land-Ocean Contrast (LOC) is an index of area-averaged surface temperature contrast between land and ocean. Meridional Temperature Gradient (MTG) is defined as the mean meridional temperature gradient in the Northern Hemisphere from mid to high latitude and sub-tropical zonal bands. These indices have direct or indirect effects on changing in atmospheric circulations and atmospheric moisture transport from north-south or east-west into East Asia (EA). In addition, warm season hydrometeorology in EA is highly associated with water supplies for coupled human and natural systems including drinking water, irrigation, hydropower generation as well as fisheries. Therefore, in this study, we developed an empirical separation approach for summer rainfall from typhoon and monsoon. An exploratory analysis was also conducted to identify the regional patterns of summer monsoon precipitation over the Korean peninsula within the context of changes in different types of temperature gradients. The results show significant and consistent changes in summer monsoon rainfall during the summer season (June-September) in South Korea.

• Journal of the Korean GEO-environmental Society
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• v.21 no.10
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• pp.5-10
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• 2020

As the demand for the recycling of industrial by-products increases due to various environmental restrictions including the prohibition of ocean disposal, various studies regarding the recycling of industrial by-products are currently being carried out. One of the industrial by-product, coal ash is produced from thermal power generation; studies on the recycling of fly ash have been actively carried out and it is currently recycled in various fields. In the case of bottom ash, however, only a portion of the total amount generated is primarily processed into a particle size of 2~4mm or less than 2mm to be used for gardening purpose and light weight aggregate and so on. The remaining amount is buried at ash disposal sites. Therefore, various studies are needed to develop measures to use bottom ash. This study aimed at identifying the optimal particle size and mixing ratio of bottom ash to be used as CLSM aggregate. To this end, it evaluated the usability of bottom ash as CLSM aggregate, by investigating the flowability and strength change characteristics of CLSM produced with regard to the mixing ratio of weathered granite soil and bottom ash, particle size of bottom ash to be mixed and soil binder addition rate and conducting a heavy metal leaching test.

• Journal of The Korean Association For Science Education
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• v.40 no.1
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• pp.51-60
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• 2020

In this study, we propose research methods to explore the nature of earth science by applying the phenomenological approach and NOS-family resemblance approach based on literature review. The phenomenological approach exploring the nature of earth science is a method of collecting, analyzing and synthesizing multifaceted features of earth science from intuitive sensory phenomena without prejudice. As a way of exploring the nature of earth science from a phenomenological point of view, we propose the NOS-family resemblance approach to the NOS. This approach provides a comprehensive explanation of NOS by combining the characteristics shared by different areas of science with distinct differences. Applying this method to exploring the nature of earth science, we can identify both domain-general and domain-specific characteristics that make sub-areas of earth science a 'family.' For example, through the networking of features shared by such sub-areas as geology, atmospheric science, oceanography, astronomy, earth system science, etc., we can extract the family-resemblance characteristics that make these sub-areas a family called earth science. Through these approaches to the nature of earth science, the richness, complexity, and dynamic nature of earth science can be revealed as a whole. In addition, we will be able to grasp the change in the sub-areas that constitute the earth science, which in turn changes the nature of earth science, and to contribute to establishing the status and development system of earth science as a school subject.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.2
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• pp.15-22
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• 2012

The variation in the wind speed with height above ground is called the wind shear profile. In the field of wind resource assessment, analysts typically use one of two mathematical relations to characterize the measured wind shear profile: the logarithmic profile (log law) and the power law profile (power law). The logarithmic law uses the surface roughness as a parameter, and the power law uses the power law exponent as a parameter. The shape of the wind shear profile typically depends on several factors, most notably the roughness of the surrounding terrain and the stability of the atmosphere. Since the atmospheric stability changes with season, time of day, and meteorological conditions, the surface roughness and the power law exponent also tends to change in time. For this study, Using the observed data from Met-mast, located in Pyeongdae, Handong in Jeju. we used the matlab and windograper to calculate roughness length and the law exponents. These calculations are similar to reference the data, but they have different ranges. In the ocean case, each reference data and calculated data was the same, but the crop area is higher than the earlier studies. In addition, the agricultural village is lower than the earlier studies.