• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.3
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• pp.292-298
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• 2016

In this research, considering the practical situation of separated placing method for mass concrete structure, an efficient method of controlling the heat of hydration is suggested by comparing between the simulated values and actual measurements conducted with the optimum mix design obtained from the various mix conditions with different types and amount of supplementary cementitious materials(SCMs). As the result of the research, firstly, the optimum mix designs for top and bottom layers were determined by Midas gen as OPC to FA of 85 to 15, and OPC to FA to BS of 50 to 20 to 30, respectively. The concrete mixtures prepared with the mix designs determined from the simulation satisfied the target performance range in slump, air content and compressive strength. Additionally, from temperature measurement for the actual mass concrete placed during spring, the maximum temperature difference between surface and core was about $10^{\circ}C$ with 59 and $49^{\circ}C$ for top and bottom layers, respectively, and 1.4 of cracking index was obtained. Therefore, considering the practical conditions of mass concrete construction, it is considered that the different heat of hydration method using different mix designs with SCMs can be an efficient method for controlling thermal cracking and settling cracking of mass concrete.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.617-623
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• 2020

Urban railroad vehicles carry many passengers and are the core of an urban railroad transportation system. Therefore, the dynamic performance of the vehicle must be ensured. Dynamic behaviors such as the vibration and ride comfort of railway vehicles are affected by the structure of the suspension system. We analyzed the dynamic behavior of a railway vehicle according to the suspension system of an urban railway vehicle, which is mainly operated in Korea. For two types of vehicles with different suspension structures, the vibration of the vehicles on railway tracks was measured, and dynamic behavior characteristics such as vibration, ride, and vibration reduction rate were analyzed. The result of the test shows that the vibration performance of the body is superior to that of B-bogie in the lateral direction and that of A-bogie in the vertical direction. Overall, the ride quality of the A-bogie car is superior to that of B-bogie. When analyzing the vibration attenuation rate of primary suspension system, the vibration attenuation performance of B-bogie with coil spring was superior to that of A-bogie with a conical rubber spring. The secondary suspension system has better vibration attenuation performance for A-bogie with air springs compared to coil springs.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.150-158
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• 2013

In Korea, the official monitoring of the atmospheric re-entry of satellites or space debris was initiated by the first operation of a re-entry situation analysis team for the 'Cosmos 1402' of the Soviet Union, which main body re-entered on January 23, 1983 and radio active core re-entered on February 7, 1983. After this incident, a task force team consisting Korea Astronomy and Space Science Institute (KASI), Korea Aerospace Research Institute (KARI) and other related institutes operated a situation monitoring group under the supervision of the Ministry of Science and technology (MOST) for the controlled re-entry of the Russian 'Mir' space station in 2001. The re-entry of the upper atmospheric weather satellite 'UARS' of United States had been monitored and analyzed by KASI on September 24, 2011. As the re-entry of the space object has been frequently occurred, the government officials and the experts from MEST (Ministry of Education, Science and Technology), KASI, KARI had an urgent official meeting to establish a satellite re-entry monitoring room in KASI and to give an operational authority to KASI in September 14, 2011. Under this decision, the satellite re-entry monitoring room in KASI has successfully executed the monitoring, data analyzing, official reporting, media contacting, and public announcing for the German satellite 'Roentgen' in October 2011, Russian space explorer 'Phobos-Grunt' in January 2012, Russian satellite 'Cosmos 1484' in January 2013, and European geodetic satellite 'GOCE' in November 2013 with the support from the Korean Air Force and KARI.

• Korean Security Journal
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• no.58
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• pp.35-58
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• 2019

Drone was originally developed for air force aircraft or missile exercise shooting targets, and is being considered as the entire unmanned aircraft to the public. The core concept of a drone can be divided into 'unmanned' and 'aircraft'. However, there are many questions about whether the Fourth Industrial Revolution, expressed as a convergence scientific innovation, is appropriate at a time when smart cities are proposed as a concept of new urban spatial formation, and the role of self-driving vehicles, including drones, is being emphasized within the new urban integrated transport system. In this study, the concept of the existing drones was analyzed for the development process, definitions in each country's laws, and the results of the preceding research to present a concept suitable for future society and a unified term. It is not desirable to define a drone for the purpose of a country, an institution, or an operating entity, depending on the circumstances of the era. It is more reasonable to find the concept of a drone based on human life than in the traditional way, and more reasonable considering the development of the drones in the future. Subsequent studies should be more detailed, more data and research results analyzed, and discussed areas that were not covered in this study. Based on this, research should also be conducted on a variety of topics, including legislation, preparation of operational regulations, and related industrial processes and regulations.

• Journal of the Korean Institute of Landscape Architecture
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• v.29 no.1
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• pp.131-139
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• 2001

This paper aims at surveying through case studies the planting possibility on the interval artificial ground between the bank and the core landfill of the first section of works in the SUDOKWON Landfill area landfill area which was completed, followed by the layer-on-layer landfill process involving the latch or sealing layer against emitting landfill gas from the reclaimed waste. The survey results are as follows; 1. The layers of the artificial planting ground on the landfill were established on the basis of top-on-top procedure for a waste layer, a topping soil layer (T=50cm), a gas blocking layer (broken stones T=30cm), a filter layer (non-woven fabric 700g), a sheet protecting soil layer (T=20cm), and a blocking layer (HDPE SHEET 2.0mm), an irrigation layer (SAND T=30cm), a filter layer (non-woven fabric 700g), a sheet protecting soil layer (T=20cm), and a blocking layer (HDPE SHEET 2.0mm), an irrigation layer (SAND T=30cm), a filter layer (non-woven fabric 700g), a planting layer (T=90cm+), a top mound (T=2m). 2. Since no direct damage on the planting layer affected by the landfill gas was detected, planting is found to be still possible and successful except the severely unequal subsidence portion. 3. The mortality rate is discovered different on different trees: Pinus thunbergii (H3.0$\times$W1.0m) 11.25%, Pinus thunbergii (H2.5$\times$W0.8m) 4.73%, Koelreuteira paniculata 8.67%, Hibiscus syriacus 5.68%, Deutzia parviflora 6.50%, Forsythia koreana 8.17%, Rho. yedoense v. poukhanese 32.22%, and Spiraea pru v. symplicifolia 18.89%; although the last two of which are generally considered to have a strong generic growing character, they are subject to be weakened when exposed to the contaminated microclimate of the site like landfill gas. 4. The damage rates, on Pinus thunbergii, Koelreuteria paniculata, Hibiscus syracus, Forsythia koreana, Deutzia parviflora, Rho. yedoense v. poukhanense were shown to decrease to 7.31-17.69% in the second check (June 2000) lower than 5.77-46.92% in the first examination (June 1999), whereas the damage on Spiraea pru v. symplicifolia relatively increased. It is believed that preparatory method of the air pollution, change of temperature, odor by emitting landfill gas, and minute dust from vehicles should be made, and a research on this matter will be conducted in the near future.

• Journal of the Korean Geotechnical Society
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• v.30 no.1
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• pp.65-74
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• 2014

Cemented soils have been widely used in road and dam construction, and recently ground improvement of soft soils. The strength of such cemented soils can be tested by using cored sample or laboratory-prepared specimen through unconfined compression or triaxial tests. It takes time to core a sample or prepare a testing specimen in the laboratory. In a certain situation, it is necessary to determine the in-situ strength of cemented soils very quickly and on time. In this study, the relation between unconfined compressive strength and shear wave velocity was investigated for predicting the in-situ strength of cemented soils. A small cemented specimen with 5 cm in diameter and 10 cm in height was prepared by Nakdong river sand and ordinary Portland cement. Its cement ratios were 4, 8, 12, and 16% and air cured for 7, 14, and 28 days. For recycling of resources, a blast furnace slag was also used with sodium hydroxide as an alkaline activator. The shear wave velocity for cemented soils was measured and then unconfined compressive strength test was carried out. As a cement ratio increased, the shear wave velocity and unconfined compressive strength increased due to increased density and denser structure. The relation between unconfined compressive strength and shear wave velocity increased nonlinearly for cemented soils with less than 16% of cement ratio.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2003.06a
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• pp.1-5
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• 2003

In order to prepare a basis for ecological restoration of the Seoul Metropolitan area, ecological diagnoses on soil physico-chemical properties and vegetation structure were carried out. Land use patterns, actual vegetation, and biotope patterns were also investigated based on aerial photograph interpretation and field checks. I formulated landscape elements overlaying those data and evaluated the ecological value of each element. Soil pollution was evaluated by analyzing soil samples collected in each grid on the mesh map, divided by 2km $\times$ 2km intervals. Soil samples were collected in forests or grasslands escaped from direct human interference. Soil pollution evaluated from pH, and SO$_4$, Ca, Mg, and Al contents of soil was more severe in the urban outskirts than in the urban center. Those soil environmental factors showed significant correlation with each other. Vegetation in the urban area was different in species composition from that in suburban areas and showed lower diversity compared with that in the suburban areas. Successional process investigated by population structure of major species also showed a difference. That is, successional trend was normal in suburban areas, but that in urban areas showed a retrogressive pattern. The landscape ecological map of Seoul indicates that the urban center lacks vegetation and greenery space is restricted in urban outskirts. Such an uneven distribution of vegetation has caused a specific urban climate and thereby contributed to aggravation of air and soil pollution, furthermore causing vegetation decline. From this result, it was estimated that such uneven distribution of vegetation functioned as a trigger factor to deteriorate the urban environment. I suggested, therefore, a restoration plan based on landscape ecological principles, which emphasizes connectivity and even distribution of green areas throughout the whole area of the Seoul to solve this complex environmental problem. In this restoration plan, first of all, I decided the priority order for connection of the fragmented greenery spaces based on the distances from the core reserves comprised of green belt and rivers, which play roles as habitats of wildlife as well as for improvement of urban environment. Next, I prepared methods to restore each landscape element included in the paths of green network to be constructed in the future on the bases of such preferential order. Rivers and roads, which hold good connectivity, were chosen as elements to play important roles in constructing green network by linking the fragmented greenery spaces.

• Journal of the Korean Magnetics Society
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• v.14 no.1
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• pp.52-57
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• 2004

In this research, characteristics of air core rectangular spiral type inductors of ㎓ band are numerical analyzed. The basic structure of inductors is a rectangular spiral having 390${\mu}{\textrm}{m}$${\times}$390${\mu}{\textrm}{m}$ size, 5.5 turns, line width of 10 ${\mu}{\textrm}{m}$ and line space of 10 ${\mu}{\textrm}{m}$. Frequency characteristics were simulated up to 10 ㎓. The substrate was modeled as Si, Sapphire, glass and GaAs and the conductor as Cu. The thickness of the conductor was fixed at 2. The number of turns was n.5 to make the input and output terminals to be on the opposite sides. The initial inductance of the basic inductor structure was 13.0 nH, maximum inductance 60.0 nH and resonance frequency 4.25 ㎓. As the dielectric constant of the substrate was increased, the initial inductance varied only slightly, but the resonance frequency decreased considerably. As the number of turns was varied from 1.5 to 9.5, the initial inductance was increased linearly from 2.9 nH to 15.9 nH and, then, saturated at 16.9 nH. The Q factor increased only slightly. The line width and line space of inductors were varied from 5 ${\mu}{\textrm}{m}$ to 20 ${\mu}{\textrm}{m}$, which resulted in the decrease of the initial and maximum inductances. But the resonance frequency was increased. Q factor displayed an increase and a decrease, respectively, when the line width and line space were increased.

• Tuberculosis and Respiratory Diseases
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• v.47 no.5
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• pp.691-696
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• 1999

Epithelioid hemangioendothelioma(EH) is a rare pulmonary vascular malignancy. Clinically, EH has been considered as an indolent, generally non-aggressive tumor. We report a case of EH which was confirmed by open lung biopsy. A 34-year-old woman was admitted for further evaluation of multiple small(less than 2cm in size) nodules, incidentally detected on screening chest radiograph. The chest CT showed multiple, relatively well-marginated, variable sized nodules at both whole lung. Transbronchial lung biopsy and transthoracic needle aspiration were nondiagnostic and open lung biopsy was performed from right middle lobe of lung. On light-microscopic examination, the nodules were composed of a poorly cellular hyaline core and a more cellular peripheral zone which extended into air space in a micropolypoid fashion and obliterated blood vessels. The tumor cells at the peripheral zone had intracytoplasmic vacuoles which suggested primitive, vascular differentiation. Immuno-histochemical study revealed the cellular area which gave positive reaction to factor VIII-related antigen. She received no specific therapy after open lung biopsy and chest X-ray films had showed no change for about two years.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1998.10a
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• pp.83-92
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• 1998

오존 경보제와 예보제의 실시가 오존 오염에 관한 일반인의 관심을 증폭시키는 중요한 계기가 되었음에도 우리 연구계와 정책 당국의 대응은 이에 훨씬 못미치고 있다. 1990년 이래 학회지 관련 논문 편수는 연간 1∼3편에 그치고 있고, 다른 이차오염 현상과 달리 정책 당국은 여전히 지원을 고려하지 않고 있다. 오존 연구가 뿌리를 내리지 못한 가운데 강행된 경보제와 예보제의 와중에 책임을 떠맡은 지방자치단체는 조급하게 노련한 예보 모델을 찾고 있고 충분한 검토도 없이 외국의 사례에서 대책을 구하고 있다. 논란이 되고 있는 오존 예보의 부정확성은 모델 선택의 문제가 아니라 모델 이용이 잘못된 때문이다. 현재 오존 대책의 일환으로 검토되고 있는 차량 부제 실시와 같은 단기 대책은 역효과를 낼 수 있다는 연구결과도 있다. 선진국의 오존 연구는 도시 규모에서 지역 규모로 확대되고 있고, 구츰 등 액상반응의 효과 규명과 1 kin 이하 미세 변화 모델링이 시도되고 있고, 지구 단위 대류권 실험의 일환으로 태평양 상공의 오존과 오존 전구물질의 대기화학이 조사되고 있다. 우리는 우선 우리의 오존 문제를 정확히 이해하도록 노력하여야 한다 합리적 계획 아래 체계적으로 접근하여 갈 때 당장은 아니지만 우리의 오존에 대한 이해가 깊어갈수록 예보의 정확성은 향상될 수 있다. 많은 비용과 노력이 필요한 오존 대책의 시행은 충분히 신중하여야 한다. 서울과 같은 대도시라면 적합한 수치모델을 구비하여 효과를 점검할 수 있어야 한다. 일부에서는 예보의 정확성을 높일 수 있는 방안의 하나로 수치모델 이용을 거론하고 있으나 수치모델은 매일의 예보와 같이 일상적 목적을 위하여 사용될 수 있는 모델이 아니며, 현재와 같이 기초가 갖추어져 있지 않은 상황에서는 더욱 그러하다. 정상적 모델 이용이 가능할 수 있도록 배출원 자료 체계를 갖추어야 하고, 서을 등 특징적 지역에 대하여서는 집중적 현장 조사를 실시하여야 한다.3)와 NAS(National Academy of Sciences, 1983), 미국에서 발행되는 정부 지침서 (Federal Register)에 고시된 내용 등을 토대로 하였다. 연구는 당면현실로 다가온 정보화 및 세계화의 기업환경에서 예견되는 몰입(committment)의 약화에 대한 치유방안으로서, 정보화된 경영모의게임의 기업 교육훈련 시스템(Business Training System)으로의 발전 가능성을 제시한다 하겠다.암시하며, 따라서 우리 교육문화에 맞는 재택수업 형태의 개발이 시급함을 제시한다고 하겠다.column density of HCaN is (1-3):n1014cm-2. Column density at distant position from MD5 is larger than that in the (:entral region. We have deduced that this hot-core has a mass of 10sR1 which i:s about an order of magnitude larger those obtained by previous studies.previous studies.업순서들의 상관관계를 고려하여 보다 개선된 해를 구하기 위한 연구가 요구된다. 또한, 준비작업비용을 발생시키는 작업장의 작업순서결정에 대해서도 연구를 행하여, 보완작업비용과 준비비용을 고려한 GMMAL 작업순서문제를 해결하기 위한 연구가 수행되어야 할 것이다.로 이루어 져야 할 것이다.태를 보다 효율적으로 증진시킬 수 있는 대안이 마련되어져야 한다고 사료된다.$\ulcorner$순응$\lrcorner$의 범위를 벗어나지 않는다. 그렇기 때문에도 $\ulcorner$순응$\lrcorner$과 $\ulcorner$표현$\lrcorner$의 성격과 형태를 외형상으로 더욱이 공간