• 헤리티지:역사와 과학
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• 제52권4호
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• pp.264-271
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• 2019

별을 관측하는 천문대로 잘 알려진 경주 첨성대는 그 모양과 성격이 독특하고 원래의 모습으로 잘 보존되어 있어 역사적·학술적·예술적 가치가 높은 문화재이다. 그동안 많은 연구자들이 첨성대의 외부 구조와 지반 안전성, 지진 재해 위험도 평가 연구 등 과학적인 조사를 이용한 첨성대의 평가를 진행해왔으나 첨성대의 지하 구조에 대해서는 조사가 매우 미흡하였다. 이 논문에서는 첨성대와 관련한 주변의 매장문화재 존재 여부와 첨성대의 기초부를 확인하기 위하여 지하투과레이더(GPR) 탐사를 수행하고 2차원과 3차원 영상을 통해 첨성대의 지하 구조를 정밀 분석하였다. 그 결과, 0.4~0.6m 깊이에서는 절반 정도만 남아 있긴 하지만 12개의 작은 물체들이 원형의 배치를 이루고 있고, 0.7~1m 깊이에서는 정면 4칸, 측면 3칸의 건물지로 추정되는 반응이 첨성대를 중심으로 주변에 분포하는 것이 확인되었다. 또한 첨성대의 직하부에는 이미 알고 있는 2단의 기단부 외에 7×7m 크기의 방형 시설이 깊이 0.6m에 존재하며, 깊이 1.2~3m에서는 첨성대의 기초시설로 추정되는 반응이 확인되었다. 이 기초시설은 동서 11m, 남북 12m의 타원형이며 첨성대 기단을 중심으로 북·서·동측면은 1m 이내로 짧고 남측면은 5m 정도로 넓게 분포하고 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2814-2818
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• 2000

This paper describes an image processing algorithm capable of recognizing the road lane using a CDF (Cumulative Distribution Function). which is designed for the model function of the road lane. The CDF has distinctive peak points at the vicinity of the lane direction because of the directional and positional continuities of the lane. We construct a scatter diagram by collecting the edge pixels with the direction corresponding to the peak point of the CDF and carry out the principal axis-based line fitting for the scatter diagram to obtain the lane information. As noises play the role of making a lot of similar features to the lane appear and disappear in the image we introduce a recursive estimator of the function to reduce the noise effect and a scene understanding index (SUI) formulated by statistical parameters of the CDF to prevent a false alarm or miss detection. The proposed algorithm has been implemented in a real time on the video data obtained from a test vehicle driven in a typical highway.

• Journal of KIEE
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• 제11권1호
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• pp.69-77
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• 2001

This paper describes an image processing algorithm capable of recognizing road lanes by using a CDF(cumulative distribution function). The CDF is designed for the model function of road lanes. Based on the assumptions that there are no abrupt changes in the direction and location of road lanes and that the intensity of lane boundaries differs from that of the background, we formulated the CDF, which accumulates the edge magnitude for edge directions. The CDF has distinctive peak points at the vicinity of lane directions due to the directional and the positional continuities of a lane. To obtain lane-related information a scatter diagram was constructed by collecting edge pixels, of which the direction corresponds to the peak point of the CDF, then the principal axis-based line fitting was performed for the scatter diagram. Noises can cause many similar features to appear and to disappear in an image. Therefore, to reduce the noise effect a recursive estimator of the CDF was introduced, and also to prevent false alarms or miss detection a scene understanding index (DUI) was formulated by the statistical parameters of the CDF. The proposed algorithm has been implemented in real time on video data obtained from a test vehicle driven on a typical highway.

• 정보과학회 논문지
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• 제44권6호
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• pp.587-594
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• 2017

최근, 동작 상상(Motor Imagery) Electroencephalogram(EEG)를 기반으로 한 Brain-Computer Interface(BCI) 시스템은 의학, 공학 등 다양한 분야에서 많은 관심을 받고 있다. Common Spatial Pattern(CSP) 알고리즘은 동작 상상 EEG의 특징을 추출하기 위한 가장 유용한 방법이다. 그러나 CSP 알고리즘은 공분산 행렬에 의존하기 때문에 Small-Sample Setting(SSS) 상황에서 성능에 한계가 있다. 또한 사용하는 주파수 대역에 따라 큰 성능 차이를 보인다. 이러한 문제를 동시에 해결하기 위해, 4-40Hz 대역 EEG 신호를 9개의 필터 뱅크를 이용하여 분할하고 각 밴드에 Regularized CSP(R-CSP)를 적용한다. 이후 Mutual Information-Based Individual Feature(MIBIF) 알고리즘은 R-CSP의 차별적인 특징을 선택하기 위해 사용된다. 본 연구에서는 대뇌 피질의 운동영역 부근 18개 채널을 사용하여 BCI CompetitionIII DatasetIVa의 피험자 다섯 명(aa, al, av, aw 및 ay)에 대해 각각 87.5%, 100%, 63.78%, 82.14% 및 86.11%의 정확도를 도출하였다. 제안된 방법은 CSP, R-CSP 및 FBCSP 방법보다 16.21%, 10.77% 및 3.32%의 평균 분류 정확도 향상이 있었다. 특히, 본 논문에서 제안한 방법은 SSS 상황에서 우수한 성능을 보였다.

• 천문학회보
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• 제43권1호
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• pp.65.2-65.2
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• 2018

Through MIRIS $Pa{\alpha}$ Galactic plane survey, a lot of $Pa{\alpha}$ blobs were detected along the plane. To reveal their characteristics, we are planning to collect NIR high-resolution spectroscopic data for them by using Immersion GRating INfrared Spectrograph (IGRINS). Here, we present the preliminary results of the IGRINS observations for a Herbig Be star, MWC 1080, which is one of the $Pa{\alpha}$ blobs detected in Cepheus. This Herbig Be star is known to possess a lot of young stellar objects (YSOs) and bright MIR ($10-20{\mu}m$) nebulosity in its vicinity. From IPHAS $H{\alpha}$ data, we revealed large extended $H{\alpha}$ features that correlate well with MIR and 13CO morphologies around MWC 1080. A part of the $H{\alpha}$ features shows a bow shock shape to the northeast of the primary star MWC 1080A, which seems to be due to an outflow from MWC 1080A. Through IGRINS observations, we detected faint [Fe II] ${\lambda}1.644{\mu}m$ and H2 1-0 S(1) ${\lambda}2.122{\mu}m$ emission lines around the bow shock feature. Interestingly, to the east region of MWC 1080A, we also detected strong [Fe II] and H2 emission lines with a couple of velocity components, which suggests the detection of a new outflow from another YSO. Broad $Br{\gamma}$ ${\lambda}2.1662{\mu}m$ line and H2 lines with various velocity components were detected around the bright MIR and $H{\alpha}$ nebulosity as well.

• 천문학회보
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• 제39권1호
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• pp.41.2-41.2
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• 2014

Hierarchical merging scenario indicates that galaxies go through major and minor merger events during their formation and evolution. As a result of the merging, substructural features of remnants such as stellar stream are shown around a current galaxy system. To find evidence of stellar substructures on M31 system, we used the near-infrared images of JHK filters obtained from the Wide Field Camera (WFCAM) at UKIRT 3.8m. A total sky coverage is an area of about$ 4.5^{\circ}{\times}6^{\circ}$ around M31. Indeed, M31 system which consists of several satellite systems contains stellar substructures such as giant stellar stream, loops, and spurs. By analysing stellar populations on the near-infrared color-magnitude diagrams, we selected member star candidates of each stellar substructure, from which we map out spatial distribution of stars in the vicinity of M31 system. Here, we present spatial density distribution maps of stars on each substructure over the entire field of M31 system. Also, we discuss the possible origin of the substructures and the implications on the galaxy assembly process.

• Journal of Radiation Protection and Research
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• 제28권3호
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• pp.165-172
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• 2003

본 연구에서는 국내 원자력발전소가 위치한 지역의 토양(영광, 울진, 고리, 고성, 월성)에 존재하는 휴믹산(HA)을 추출하여 각 시료의 원소성분 및 분광학적 방법(UV/Vis, IR, CPMAS $^{13}C$ NMR)을 이용한 물질 특성을 조사하였고, Aldrich HA과 함께 비교 분석하였다. 분자량 크기 분포의 차이는 한외여과법을 이용하여 조사하였다. 원소분석 결과, 울진 지역의 HA에서 가장 높은 산소 함량비를 보였으며, 고리와 고성지역의 HA에서 상대적으로 낮은 산소 함량비를 보였다(O/C: 0.51(UJHA) vs. 0.43(KRHA), 0.46(KSHA)). 분자량 크기 분포는 울진과 영광 지역의 HA가 고리와 고성 지역의 HA에 비하여 30,000 daltons이상의 고분자가 더 높게 존재함을 알 수 있었다. CPMAS $^{13}C$ NMR, UV/Vis., IR 등의 분광학적 특성분석 결과, 울진과 영광 지역의 HA가 고리, 고성 및 월성 지역의 HA에 비하여 상대적으로 높은 방향족성(aromaticity)과 산소 포함 작용기의 함량이 높은 특성을 보였다. 이상의 결과로 볼 때, 울진과 영광지역의 HA가 상대적으로 더 높은 휴믹화(humification) 단계의 물질 특성을 가짐을 알 수 있었으며, 금속이온과의 반응성이 더 높을 것으로 예측된다.

• 대한조선학회지
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• 제11권2호
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• pp.15-22
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• 1974

As for the added mass moment of inertia of ships in torsional vibration, it seems that the works by T. Kumai[1,2] are the only systematic one available currently. The work[1] is for the calculation of the two dimensional correction factors with finitely-long elliptic cylinders as the mathematic model. In this work the authors recalculated the above factors, $J_{\tau}$, with the same mathematic model and the same problem formulation, and presented the numerical results in Fig. 1. The reason why the reinvestigation was done was that in Kumai's work he obtained the solutions of the Mathieu equations, which was derived from the problem formulation for the velocity potential, under the assumption that the dummy constant q involved in the equations was always far less than unity, whereas in fact it takes values within the region of $0<q{\leq}{\infty}$ in sequence. As a result the authors found two remarkable differences in general features of $J_{\tau}$(refer to Fg.3); one that the authors' numerical results are considerably higher than the results given in [2], and the other that for a given number of node those have properties of decreasing monotonically with increase of the beam-draft ratio while these rapidly decrease from a maximum value of near at B/T=2.00 with B/T becoming greater or less than ratio. It seems that the latter trend was resulted from the fact that the assumption of $q{\ll}1$ employed in [2] was more closely satisfied in the vicinity of B/T=2.00.

• Ocean Science Journal
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• 제40권2호
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• pp.67-78
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• 2005

Complex physical, chemical and biological interactions off the Korean coast created several striking patterns in the phytoplankton blooms, which became conspicuous during the measurements of ocean color from space. This study concentrated on analyzing the spatial and temporal aspects of phytoplankton chlorophyll variability in these areas using an integrated dataset from a Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Advanced Very High Resolution (AVHRR) sensor, and Conductivity Temperature Depth (CTD) sensor. The results showed that chlorophyll concentrations were elevated in coastal and open ocean regions, with strong summer and fall blooms, which appeared to spread out in most of the enclosed bays and neighboring waters due to certain oceanographic processes. The chlorophyll concentration was observed to range between 3 and $54\;mg\;m^{-3}$ inside Jin-hae Bay and adjacent coastal bays and 0.5 and $8\;mg\;m^{-3}$ in the southeast sea offshore waters, this gradual decrease towards oceanic waters suggested physical transports of phytoplankton blooms from the shallow shelves to slope waters through the influence of the Tsushima Warm Current (TWC) along the Tsushima Strait. Horizontal distribution of potential temperature $(\theta)$ and salinity (S) of water off the southeastern coast exhibited cold and low saline surface water $(\theta and warm and high saline subsurface water $({\theta}>12^{\circ}C; S>34.4)$ at 75dBar, corroborating TWC intrusion along the Tsushima Strait. An eastward branch of this current was called the East Korean Warm Current (EKWC), tracked with the help of CTD data and satellite-derived sea surface temperature, which often influenced the dynamics of mesoscale anticyclonic eddy fields off the Korean east coast during the summer season. The process of such mesoscale anticyclonic eddy features might have produced interior upwelling that could have shoaled and steepened the nutricline, enhancing phytoplankton population by advection or diffusion of nutrients in the vicinity of Ulleungdo in the East Sea.

• 천문학회보
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• 제37권2호
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• pp.142.1-142.1
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• 2012

During the photometric runs of the eclipsing binary V432 Per in 2006, we serendipitously discovered peculiar light variations of GSC 2855-0585 that imaged on the same target field. Its brightness decreased about 0.02 mag for about 0.15 days in all B, V, and R bands. The depth, duration, and box-shaped light curves are very similar to those of typical transiting exoplanets. We gathered the time-series data of GSC 2855-0585 from the SuperWASP public archive and detected the same light variations with a period of about 2.406 days. The period and transitlike features were confirmed by photometric follow-up observations at a predicted epoch in 2010 November. In order to estimate the mass of the companion that produced the light variations, we obtained 10 high-resolution spectra with different orbital phases in 2010 November and 2011 October-December. The radial velocities showed large variations of about 44 km/s. It indicates that the transitlike light variations do not originate from a transiting exoplanet, but from the single-lined spectroscopic eclipsing binary with a cool dwarf companion. Using the photometric and spectroscopic data, we estimated the physical parameters of the eclipsing binary GSC 2855-0585, such as orbital period, effective temperature, surface gravity, and mass.