• Journal of Astronomy and Space Sciences
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• 제35권2호
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• pp.83-92
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• 2018

The summer polar lower thermosphere (90-100 km) has an interesting connection to meteors, adjacent to the mesopause region attaining the lowest temperature in summer. Meteors supply condensation nuclei for charged ice particles causing polar mesospheric summer echoes (PMSE). We report the observation of meteor trail with nearly horizontal transit at high speed (20-50 km/s), and at last with re-enhanced echo power followed by diffusive echoes. Changes in phase difference between radar receivers aligned in meridional and zonal directions are used to determine variations in horizontal displacements and speeds with respect to time by taking advantage of radar interferometric analysis. The actual transit of echo target is observed along the straight pathway vertically and horizontally extended as much as a distance of at least 24 km and at most 29 km. The meteor trail initially has a signature similar to 'head echoes', with travel speeds from 20 - 50 km/s. It subsequently transforms into a different type of echo target including specular echo and then finally the power reenhanced. The reenhancement of echo power is followed by fume-like diffusive echoes, indicating sudden release of plasma as like explosive process probably involved. We discuss a possible role of meteor-triggered secondary plasma trail, such as fireball embedded with electrical discharge that continuously varies the power and transit speed.

• 한국추진공학회지
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• 제21권2호
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• pp.102-110
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• 2017

발사대시스템의 산화제공급계(Liquid Oxygen Filling System)는 발사체의 추진제(Propellant) 중 연료의 연소를 위한 산화제(Oxidizer)로 사용되는 액체산소(Liquid Oxygen)를 저장하고, 발사체 요구조건에 맞게 공급하는 하는 설비이다. 본 논문에서는 한국형발사체(KSLV-II) 발사대시스템 상세설계(Critical Design, 2015년 8월에서 2016년 4월, 8개월) 동안 수행된 한국형발사체 발사대시스템 추진제 공급설비의 산화제공급계 설계 내용을 주요 설비 구성에 대하여 구조적 관점으로 소개한다.

• Clinical and Experimental Pediatrics
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• 제53권1호
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• pp.97-102
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• 2010

림프관종은 드물게 발생하는 림프혈관의 양성 과오종으로, 주로 두경부에 호발하는데, 혀나 구저부 또는 심 경부에 발생할 경우 원심성 림프관 흐름의 방해로 이차적 거설증이 발생할 수 있다. 저자들은 출생 시에는 경부 또는 하악 부종 없이 거설증만 보였던 두 명의 환아에서 각각 생후 5개월과 5주에 하악 부종이 보여 MRI로 심 경부 림프관종을 확인한 2례를 경험하였기에 보고하는 바이다.

• 디지털콘텐츠학회 논문지
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• 제18권2호
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• pp.275-282
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• 2017

디지털 기술의 발전과 함께 영화콘텐츠도 다양하게 변화하고 있다. 웹과 모바일 등의 플랫폼들이 개발되면서 이에 맞는 영화콘텐츠들이 등장하였다. 그러나 최근 화두가 되고 있는 가상현실 기술과 디바이스의 발달에도 불구하고 아직 영화콘텐츠 분야의 연구는 미비하다. 본 연구는 HMD(Head Mounted Display) 기반의 가상현실영화 제작을 위하여 로토스코핑 기법 활용한 영화의 미학적 활용을 중심으로 연구를 진행하였다. 먼저 기존의 가상현실 영화 중 그래픽 정보를 활용하여 미학적 표현을 한 사례인 'Notes on Blindness'와 'Pearl' 사례에서 어떻게 가상현실 공간을 미학적으로 표현하였는지를 살펴보았다. 이를 통해 그래픽화된 공간이 가상현실의 관객에게 새로운 미학적 경험을 제공하는 것을 발견하였다. 또한 실사기반 영상에 로토스코핑 기법을 활용한 '웨이킹 라이프' 와 '스캐너 다클리' 사례를 통해 로토스코핑 기법의 판타지적 활용과 성공 사례를 분석하였다. 마지막으로 실사기반의 가상현실 영화에서 관객의 몰입과 욕망의 충족을 위해 '그네 타는 소녀' 작품에 로토스코핑 기법을 적용하여 미학적으로 활용하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1430-1436
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• 2007

A principal components analysis (PCA) of the median head-related impulse responses (HRIRs) in the CIPIC HRTF database reveals that the individual HRIRs can be adequately reconstructed by a linear combination of 12 orthonormal basis functions. These basis functions can be used generally to model arbitrary HRIRs, which are not included in the process to obtain the basis functions. To clarify whether these basis functions can be used to model other set of arbitrary HRIRs, an numerical error analysis for modeling and a series of subjective listening tests were carried out using the measured and modeled HRIRs. The results showed that the set of individual HRIRs, which were measured in our lab using different measurement conditions, techniques, and source positions, can be well modeled with reasonable accuracy. Furthermore, all subjects reported not only the accurate vertical perception but also the front-back discrimination with the modeled HRIRs based on 12 basis functions. However, as less basis functions were used for HRIR modeling, the modeling accuracy and localization performance deteriorated.

• 천문학회지
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• 제41권5호
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• pp.139-145
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• 2008

The molecular cloud, embedding AFGL 2591, has a "head-and-tail" structure with a total mass of ${\sim}\;1800\;M_{\odot}$, about half of the mass (${\sim}\;900\;M_{\odot}$) in the head (size ${\sim}\;1.2\;pc$ in diameter), and another half in the envelope (${\sim}\;3.5\;pc$ in the east-west direction). We found a new cloud in the direction toward north-east from AFGL 2591 (projected distance ${\sim}\;2.4\;pc$), which is probably associated with the AFGL 2591 cloud. The $^{12}CO$ spectrum clearly shows a blue-shifted high-velocity wing at around the velocity $-20\;{\sim}\;-10\;km\;s^{-1}$, but it is not clear whether this high-velocity component has a bipolar nature in our observations. The observed CN spectra also show blue-shifted wing component but the existence of the red-shifted component is not clear, either. In some CN and HCN spectra, the highvelocity components appear as a different velocity component, not a broad line-wing component. The dense cores, traced by CN and HCN, exist in the 'head' of the AFGL 2591 cloud with an elongated morphology roughly in the north-south direction with a size of about 0.5 pc. The abundance ratio between CN and HCN is found to be about 2 - 3 within the observed region, which may suggest a possibility that this core is being affected by the embedded YSOs or by possible shocks from outside.

• 전기전자학회논문지
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• 제22권3호
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• pp.558-564
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• 2018

In distributed estimation where each node can collect only partial information on the parameter of interest without communication between nodes and quantize it before transmission to a fusion node which conducts estimation of the parameter, we consider a novel quantization technique employed at local nodes. It should be noted that the performance can be greatly improved if each node can transmit its measurement to one designated node (namely, head node) which can quantize its estimate using the total rate available in the system. For this case, the best strategy at the head node would be simply to partition the parameter space using the generalized Lloyd algorithm, producing the global codewords, one of which is closest to the estimate is transmitted to a fusion node. In this paper, we propose an iterative design algorithm that seeks to efficiently assign the codewords into each of quantization partitions at nodes so as to achieve the performance close to that of the system with the head node. We show through extensive experiments that the proposed algorithm offers a performance improvement in rate-distortion perspective as compared with previous novel techniques.

• 한국식생활문화학회지
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• 제31권5호
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• pp.411-429
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• 2016

This study introduced "Dongchundang Eumsikbeop" and examined its value as a reference. "Dongchundang Eumsikbeop" is a recipe book from the Head House of Eunjin Song Clan. As the author is unknown, the book is named after where it was found. "Dongchundang Eumsikbeop" records the recipes for 32 total foods, including 12 types of fermented foods, eight types of liquor, and six types of side dishes, etc. In "Jusiksiui", written by the same clan 100 years before, fermented foods account for 15% of its contents. On the other hand, this book assigns 34% of its space to fermented foods. It is assumed that the recipe book must have been compiled according to what households ate the most, as hostesses had to cook for their households due to financial difficulties at the time. In "Dongchundang Eumsikbeop", baking soda and alum were used as leavening agents for confectionery while sugar-based caramelizing was used for making soy sources, implying that modern food techniques were already applied. In short, this book provides a glimpse into the wisdom of hostesses of the Head House who improved recipes to suit changing times while adhering to tradition.

• 한국기계가공학회지
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• 제16권5호
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• pp.47-54
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• 2017

This study examines the implementation of a kinematic machining tool to evaluate the interference and collision phenomenon of 5-axis machining of wing ribs from airplanes, particularly for a large-size model airplane. We develop a machine simulation model of a parallel kinematic machining tool that can operate in a virtual space, which is equivalent to the authentic conditions in the field. The investigation of the simulation function elements indicates the necessity to generate the 6-axis machining, which attaches an angle head to the main axis of the machine. Using an NC program for the wing ribs, we attempt to verify the correspondence and conformity between the machine simulation model and the actual equipment.

• 터널과지하공간
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• 제31권3호
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• pp.198-209
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• 2021

최근 노후화와 기능적 요건을 만족하지 못하여 불용하는 스틸 셸 구조물의 해체 수요가 증가하면서 스틸셸 구조물 해체에 대한 관심이 부각되고 있다. 본 시공사례는 구조적 노후화와 기능적 요건을 충족하지 못하는 스틸 셸 구조물인 굴뚝과 수조의 해체에 발파해체공법 중 전도공법을 적용하였다. 발파해체 결과, 스틸 굴뚝과 스틸 수조는 예측된 방향으로 정확히 전도되었으며, 주변 시설물에 피해 없이 발파해체를 완료하였다.