• 융합신호처리학회논문지
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• 제16권4호
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• pp.162-167
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• 2015

본 논문에서는 한일상관센터에서 운영하고 있는 대전상관기의 복층패턴에 대한 원인과 문제 해결에 대해 기술한다. 대전상관기의 상관결과에서 입력신호의 전력파워가 잡음에 묻힐 정도로 작은 경우에는 잘 보이지 않지만, 전력파워가 큰 경우 입력신호에 특정한 패턴을 가진 신호가 출현하는 문제가 보고되었다. 이는 관측데이터의 상관결과와 소프트웨어 상관기와 비교하여 AIPS 소프트웨어에서 분석할 때 관측결과의 천체신호 진폭이득에는 3% 정도의 영향을 미치고 있음이 확인되었다. 따라서 복층패턴의 문제를 해결하기 위해 주기적으로 발견되는 복층패턴의 원인으로 상관기의 데이터 입력과 직렬화를 담당하는 모듈에서 메모리 관리 영역에 문제가 있음을 발견하였다. 즉, 직렬화 모듈에서 데이터를 직렬화할 때 할당된 각 메모리 영역의 데이터가 반복적으로 읽혀져 직렬화되면서 중복된 데이터가 마지막으로 할당된 메모리의 데이터와 중첩이 되면서 발생하는 것이다. 따라서 직렬화 모듈의 메모리 관련 영역의 FPGA 프로그램을 수정하여 문제를 해결하여, 정상적인 상관결과가 출력되는 것을 확인하였다.

• 한국지형학회지
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• 제25권3호
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• pp.71-87
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• 2018

As part of further study on Gwangseungri coastal deposits which occurred at 10 ~ 15m above sea level and was analyzed as palaeo-coastal flood-type sediments, six burial ages of six additional samples from the two cross sections (KST1 and, KST2) near to the points of the past study were estimated and the geochemical analysis was performed. Further investigation on the cross section KST1 revealed a reversal of the burial age at the bottom of the section which was identified as palaeo-flooding sediments and supposed to have been buried about 350 years ago. At the lower part of the KST1, the burial age of the sediment layer was estimated to be 3,800 years. The lower part of KST2 sediments was identified as sediments that was formed about 6,600 years ago and about 20,000 years ago. Considering the inclination of the sediment layers, the coastal flooding sedimentsreported to have formed 700 years ago in the previousstudy are located at the top and the KST1 section analyzed in thisstudy seemed to be connected to the lower part. The chemical analysis showed that the relationship between these layers was not continuous but had a discontinuous characteristic influenced by a specific event, and the chemical composition also showed a rapid change. If we judge these together, the lowest part of Gwangseungrisediment layerseemed to have formed during the last glacial period but it was hard to find its origins clearly. On top of this layer, a fine sediment layer containing gravels was also formed.Itseemed thatsedimentation did not occur continuously, but was affected by temporary events in such a way that after a sediment layer was formed, it stopped. Since then, a coastal flooding event occurred about 700 years ago, and part of flooded sediments accumulated in the rear slope. After that, when a flood layer including additional granular materials about 350 years ago was formed, sedimentation along the slope seemed to have occurred.

• Journal of Forest and Environmental Science
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• 제24권2호
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• pp.89-97
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• 2008

Based on the former researches, this article studied the influence of cone harvesting of Korean pine on the regeneration of Korean pine trees and the life of animals in Mt. Changbai Nature Reserve. When the cone matures, scales of the cone do not open so the seeds can not be released automatically. And the seeds, if left inside, are hard to germinate and can not grow further into seedlings. The seeds of Korean pine have deep dormancy characteristics. Natural regeneration of Korean pine is very poor under mother trees. Hoarding behavior of dispersing animals not only helps animals for food shortage period but also contributes to the dispersion of seeds of Korean pine. Among those hoarding animals, squirrel and Eurasian nutcrackers are found to be the most important dispersing agents for the seeds of Korean pine. After cone harvesting, the number of those dispersers reduced a lot since the seeds of Korean pine are very important food for them. Seed quantity of Korean pine on surface layer became very few and most of them only showed single distribution. Most of the seeds were buried under litter layer and showed a single or 2-4 seeds/cluster distribution. The case of more than 4 seeds in one cluster was few. The seed quantity of Korean pine forest on steep slopes of the research area was only 0.3% of the seed quantity in 1980 for the same forest type. If seed source of Korean pine are not protected, Korean pine forest in Mt. Changbai Nature Reserve would not maintain present feature in the future.

• 보존과학회지
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• 제33권3호
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• pp.167-179
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• 2017

서산 비경도 출수 상평통보를 대상으로 혐기성 수중 매장환경에서 형성되는 부식화합물 성분과 이에 따른 혐기성 부식 원인을 추정하였다. 미세조직 관찰, 원소 mapping, 층위별 주성분 분석, 부식화합물 동정을 실시하였다. 그 결과 표면의 고착물은 침상형 육면체형 팔면체형으로 분류되며, 그에 따른 분석 결과 Cu, Pb, S 등의 원소가 검출되었다. 원소 mapping에서는 최외곽에 Cu-S로 이루어진 뚜렷한 층이 확인되었다. 층위별 주성분은 Cu, S, Pb 등이 검출되었고, Zn은 검출되지 않았다. 부식화합물은 $PbCO_3$(고착물), $Cu_{1.96}S$(소지금속)이 나타났다. 따라서 서산 비경도 출수 상평통보의 혐기성 부식 특성은 탈아연, 황화동, 납화합물 세 가지로 요약할 수 있다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 추계학술대회
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• pp.292-294
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• 2021

디지털 트윈 기반 스마트 파이프 통합 관리 시스템은 자기진단 및 상태 감시 기능 센서 기능이 있는 수로 파이프를 지하에 매설하여, 이로부터 데이터를 전송받아 효율적인 운영 및 감시를 위한 통합 솔루션으로 스마트한 의사결정을 통하여 지하 상하 수도관을 혁신적으로 운영할 수 있는 시스템이다. 원격제어및 모니터링이 주요한 기능의 하나이기 때문에 어떻게 실시간으로 모니터링을 구성할 것인가 하는 사안은 중요한 이슈이다. 우리는 이를 위하여 특별한 실시간 기반의 에이전트 기능을 설계하였다. 본 논문에서는 이러한 이슈를 해결하기 위하여 센서 데이터들을 주고받는 전송 포인트를 기준으로 계층적 구조(Layered Architecture)를 제안하였다. 각각의 계층들에는 에이전트를 위치시키어 하위 계층을 바라보고 센서의 변화가 있는지를 실시간으로 주기적 감시를 진행하도록 하였다. 이에 대한 에이전트 시스템을 설계하고 개념모델 수준의 구현을 진행하여 우수성을 검증하였다.

• ETRI Journal
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• 제27권5호
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• pp.551-556
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• 2005

We have demonstrated a high-power widely tunable sampled grating distributed Bragg reflector (SGDBR) laser integrated monolithically with a semiconductor optical amplifier (SOA) having a lateral tapered waveguide, which is the first to emit a fiber-coupled output power of more than 10 dBm using a planar buried heterostructure (PBH). The output facet reflectivity of the integrated SOA using a lateral tapered waveguide and two-layer AR coating of $TiO_2\;and\;SiO_2$ was lower than $3\;{\times}\;10^{-4}\;over$ a wide bandwidth of 85 nm. The spectra of 40 channels spaced by 50 GHz within the tuning range of 33 nm were obtained by a precise control of SG and phase control currents. A side-mode suppression ratio of more than 35 dB was obtained in the whole tuning range. Fiber-coupled output power of more than 11 dBm and an output power variation of less than 1 dB were obtained for the whole tuning range.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.35-35
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• 2009

Capacitorless one transistor dynamic random access memory (1T-DRAM) cells were fabricated on the fully depleted strained-silicon-on-insulator (FD sSOI) and the effects of silicon back interface state on buried oxide (BOX) layer on the memory properties were evaluated. As a result, the fabricated 1T-DRAM cells showed superior electrical characteristics and a large sensing current margin (${\Delta}I_s$) between "1" state and "0" state. The back interface of SOI based capacitorless 1T-DRAM memory cell plays an important role on the memory performance. As the back interface properties were degraded by increase rapid thermal annealing (RTA) process, the performance of 1T-DRAM was also degraded. On the other hand, the properties of back interface and the performance of 1T-DRAM were considerably improved by post RTA annealing process at $450^{\circ}C$ for 30 min in a 2% $H_2/N_2$ ambient.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.166-166
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• 2013

Mesoporous $SiO_2$-supported Ni catalysts (Ni/$SiO_2$ and Ni/$TiO_2$/$SiO_2$) were fabricated by atomic layer deposition (ALD), and their catalytic activity and stability were investigated in carbon dioxide reforming of methane (CRM) reaction at $800^{\circ}C$ The Ni/$SiO_2$ catalysts showed high stability as a result of confinement of Ni particles with a mean size of ~10 nm within the pores of $SiO_2$ support. Besides, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) results showed that the Ni nanoparticles were partially buried inside the $SiO_2$ support. The strong interaction between Ni and the $SiO_2$ support could also be advantageous for long-term stability of the catalyst. In case of the Ni/$TiO_2$/$SiO_2$ catalyst, it was found that the catalytic activity of 10 nm-sized Ni nanoparticles was not much influenced by $TiO_2$ addition.

• 한국전기전자재료학회논문지
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• 제13권6호
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• pp.514-519
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• 2000

This paper describes on the temperature characteristics of a SDB(silicon-wafer direct bonding) SOI(silicon-on-insulator) Hall sensor. Using the buried oxide $SiO_2$as a dielectrical isolation layer a SDB SOI Hall sensor without pn junction has been fabricated on the Si/ $SiO_2$/Si structure. The Hall voltage and the sensitivity of the implemented SOI Hall sensor show good linearity with respect to the applied magnetic flux density and supplied current. In the temperature range of 25 to 30$0^{\circ}C$ the shifts of TCO(temperature coefficient of the offset voltage) and TCS(temperature coefficient of the product sensitivity) are less than $\pm$6.7$\times$10$_{-3}$ and $\pm$8.2$\times$10$_{-4}$$^{\circ}C$ respectively. These results indicate that the SDB SOI structure has potential for the development of a silicon Hall sensor with a high-sensitivity and high-temperature operation.

• 한국전기전자재료학회논문지
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• 제21권1호
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• pp.1-4
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• 2008

The electrical characteristics of polycrystalline silicon (poly-Si) thin film transistor (TFT) crystallized by excimer laser annealing (ELA) method were evaluated, The polycrystalline silicon thin-film transistor (poly-Si TFT) has higher electric field-effect-mobility and larger drivability than the amorphous silicon TFT. However, to poly-Si TFT's using conventional processes, the temperature must be very high. For this reason, an amorphous silicon film on a buried oxide was crystallized by annealing with a KrF excimer laser (248 nm)to fabricate a poly-Si film at low temperature. Then, High permittivity $HfO_2$ of 20 nm as the gate-insulator was deposited by atomic layer deposition (ALD) to low temperature process. In addition, the solid phase crystallization (SPC) was compared to the ELA method as a crystallization technique of amorphous-silicon film. As a result, the crystallinity and surface roughness of poly-Si crystallized by ELA method was superior to the SPC method. Also, we obtained excellent device characteristics from the Poly-Si TFT fabricated by the ELA crystallization method.