• 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.

• Geophysics and Geophysical Exploration
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• v.12 no.2
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• pp.192-198
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• 2009

Side scan sonar and SBP (sub-bottom profiler) play a very important role in the survey for seafloor imaging and sub-bottom profiling. In this study, we have acquired side scan sonar and SBP data from the artificial reef area. We applied digital image processing techniques to side scan sonar data in order to improve an image quality. For the enhancement of data quality and image resolution, we applied the typical seismic data processing sequence including gain recovery, muting, spectrum analysis, predictive deconvolution, migration to SBP data. We could easily estimate if artificial reef structures were settled properly and their distribution on the seafloor from the integrated interpretation of side scan sonar and SBP data. From the sampling analysis of seabed sediments, texture filtering of side scan sonar data and SBP data interpretation, we could evaluate the sediment type, distribution and thickness of seafloor sediments in detail.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.357-364
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• 2012

For this study, real estate brokerage services to customers how to evaluate quality factors and quality factors important for studying about what is preferred. Real estate brokerage service quality factors, the expertise of brokers, dealers sales skills, a sense of responsibility of traders, brokerage firm's position, whether or not participating were chosen franchise. Looking at the findings, and customer service quality factors, the five kinds of real estate brokers a sense of responsibility to be the most important quality factors were analyzed as a favorite, followed by the expertise of brokers, sales skills brokers, brokerage firm's presence, a franchise analysis of whether the order has been participating. As the results of this study, the traders as traders sense of responsibility and expertise and strive to improve, friendly servece and act as an active intermediarv will need to improve sales skills. Continuous promotion of the brokerage firm's position is shown to be critical, franchise affiliated businesses in order to make use of an efficient information network of the Internet is seen to be in need of improvement. This paper, we have experienced a real estate brokerage contracts require customers a service directly to find out whether the data obtained through interviews with the empirical analysis is Therefore, work-related departments of Ministry of Land and brokerage herein with reference to the Association to take measures to Once you have contributed little bit. Brokerage industry and the traders themselves, as well as the competition is to the straight ahead Do not look at a value for the development of brokerage will be constantly working.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.607-614
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• 2014

This article aims to explore and discuss research trends in global cruise industry using keyword network analysis. We visualize keyword networks in each of four groups of 1982-1999, 2000-2004, 2005-2009, 2010-2014 based on the top 20 keyword nodes' degree centrality and betweenness centrality which are selected among four centrality measurements, comparing them with frequency order. The article shows that keyword frequency collected from 240 articles published in international journals is subject to Zipf's law and nodes degree distribution also exhibits power law. We try to find out research trends in global cruise industry to change some important keywords diachronically, visualizing several networks focusing on the top two keywords, cruise and tourism, belonging to all the four year groups, with high degree and betweenness centrality values. Interestingly enough, a new node, China, connecting the top most keywords, appears in the most recent period of 2010-2014 when China has emerged as one of the rapid development countries in global cruise industry. Therefore keyword network analysis used in this article will be useful to understand research trends in global cruise industry because of increase and decrease of numbers of network types in different year groups and the visual connection between important nodes in giant components.