• Journal of information and communication convergence engineering
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• 제15권2호
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• pp.73-78
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• 2017

A general linearly constrained broadband adaptive array is examined in the eigenvector space with respect to the optimal weight vector and the adaptive algorithm. The optimal weight vector and the general adaptive algorithm in the eigenvector space are obtained by eigenvector matrix transformation. Their operations are shown to be the same as in the standard coordinate system except for the relevant transformed vectors and matrices. The nulling performance of the general linearly constrained broadband adaptive array depends on the gain factor such that the constraint plane is shifted perpendicularly to the origin by an increase in the gain factor. The general linearly constrained broadband adaptive array is observed to perform better than a conventional linearly constrained adaptive array in a coherent signal environment, while the former performs similarly to the latter in a non-coherent signal environment.

• 한국항공우주학회지
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• 제42권3호
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• pp.199-212
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• 2014

본 논문은 무인전투기를 위한 일대일 근접 교전 상황에서의 가상 추적점을 이용한 자율 공중 교전 법칙에 관해 기술하였다. 가상의 지연 및 선도 추적점으로 구성된 가상 추적점은 전술 교전 기동을 수행하기 위해서 도입한 것으로 각 가상 추적점은 전투기의 공력 특성과 기본 전투 기동의 선회원, 총 에너지 및 무기 거동 특성을 고려하여 생성된다. 무인전투기는 현재의 교전 상태를 기반으로 기동 전환을 위해 각 추적 기동의 확률을 평가하는 스무딩 함수를 이용해 단일의 가상 추적점을 결정하고 추적 기동을 실시하게 된다. 제안된 기법은 상용 전투기 모델과 X-Plane 시뮬레이터를 이용한 고충실도의 실시간 교전시뮬레이션을 통해 성능을 검증하였다.

• 한국항공우주학회지
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• 제43권3호
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• pp.265-271
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• 2015

본 연구에서는 소형 위성카메라의 영상성능 저하를 궤도상에서 능동적으로 보정하기 위해 광학보정장치를 적용한 위성카메라의 광학설계를 수행하였다. 2개의 광학 보정장치는 각각 부반사경 및 초점면부에 부착되며 총 5자유도의 운동이 가능하다. 본 논문에서 설계한 광학부는 슈미트-카세그레인(Schmidt-Cassegrain)타입으로 주반사경의 직경은 200mm이고, GSD 3.8m, MTF 성능은 약 50% 정도이다. 설계된 광학계는 수차곡선과 Spot diagram과 MTF를 통해 성능평가를 수행하였다. 수차곡선을 통해 광학성능에 가장 큰 영향을 미치는 수차가 구면수차인 것을 확인 할 수 있고, MTF 해석을 통해서 나이퀴스트 주파수에서 MTF 30%이상의 요구 성능을 충분히 만족하는 것을 확인하였다.

• 한국의상디자인학회지
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• 제25권2호
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• pp.97-110
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• 2023

The purpose of this study is to develop 3D pattern textile design of traditional Jogakbo motifs and fashion products using it. As a research method, first, through literature review, the three-dimensional representation of geometry on a plane with Jogakbo, design cases were examined. Second, through a survey, the purchase perception and design preference of Jogakbo cultural products was analyzed. Third, based on the results of the survey on color and print, the 3D pattern design for each type of Jogakbo is printed, and then textile fashion cultural products were developed. The results of this study are as follows. First, the reason why the public was not attracted to the purchase of cultural products was disatisfaction with practicality, unsuitable preference, price adequacy, aesthetics, and originality. Therefore, it was analyzed that quality, practicality, price, carry-on storage harmony and manageability, as well as aesthetic design were important factors for consumers. Second, the stereoscopic space on the plane expanded the two-dimensional plane space by forming a cube through the division and dissolution of geometry could be visualized using color expression of cubes of different brightness depending on the direction of light. Third, Jogakbo had eight types consisting of four detailed forms and three arrangement methods. The 3D pattern design could be developed through regular disolution and stereoscopic construction using Jogakbo's representative images for each type. In addition, it was found that it was easy to produce Jogakbo fashion products suitable for modern people through 3D pattern digital textile printing applying traditional colors.

• 천문학논총
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• 제31권3호
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• pp.35-41
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• 2016

We have constructed a wide-field photometric survey system called as the Korea Microlensing Telescope Network (KMTNet) in 2015. It consists of three 1.6 m optical telescopes equipped with mosaic CCD cameras. Four 9k CCDs were installed on the focal plane of each telescope. In this paper, we present the crosstalk analysis of the KMTNet mosaic CCD images. The crosstalk victims caused by bright sources were visible at eight sub-images obtained through different readout ports of each CCD. The crosstalk coefficients were estimated to be several tens of $10^{-4}$ in maximum, differing from sub-image to sub-image, and the non-linearity effect certainly appeared at the victims made from saturated sources. We developed software functions to correct the crosstalk effect of the KMTNet CCD images. The software functions showed satisfying results to remove clearly most of the crosstalk victims and have been implemented in the KMTNet image processing pipeline since 2015 September.

• 천문학회지
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• 제52권6호
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• pp.227-233
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• 2019

We report the performance of the 13.7-meter Taeduk Radio Astronomy Observatory (TRAO) radio telescope. The telescope has been equipped with a new receiver, SEQUOIA-TRAO, a new backend system, FFT2G, and a new VxWorks operating system. The receiver system features a 16-pixel focal plane array using high-performance MMIC preamplifiers; it shows very low system noise levels, with system noise temperatures from 150 K to 450 K at frequencies from 86 to 115 GHz. With the new backend system, we can simultaneously obtain 32 spectra, each with a velocity coverage of 163 km s^-1 and a resolution of 0.04 km s^-1 at 115 GHz. The new operating system, VxWorks, has successfully handled the LMTMC-TRAO observing software. The main observing method is the on-the-fly (OTF) mapping mode; a position-switching mode is available for small-area observations. Remote observing is provided. The antenna surface has been newly adjusted using digital photogrammetry, achieving a rms surface accuracy better than 130 ㎛. The pointing uncertainty is found to be less than 5" over the entire sky. We tested the new receiver system with multi-frequency observations in OTF mode. The aperture efficiencies are 43±1%, 42±1%, 37±1%, and 33±1%, the beam efficiencies are 45±2%, 48±2%, 46±2%, and 41±2% at 86, 98, 110, and 115 GHz, respectively.

• 한국음향학회지
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• 제14권1호
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• pp.115-122
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• 1995

균일한 소자 (안테나 또는 감지기) 간격으로 계수치를 체감하는 것보다 균일한 계수치로 소자의 간격을 체감하는 것이 실용적이며, 직사각형 어레이에서는, 삼각형 격자 구조가 직사각형 격자구조 보다 소자 수를 줄이는데 더 경제적이다. 접지판 위에 설치된 삼각형 격자 구조를 가진 직사각형 위상어레이의 성능을 향상시키기 위하여 소자간격 체감 방법을 제안하였다. 소자간격 체감이 주빔(main beam)의 폭과 측면로브(sidelobe)의 높이에 미치는 영향을 논의하였다. 제안된 방법을 사용한 결과 측면로브의 성능이 향상되었으나 주빔폭은 약간 넓어지는 것이 밝혀졌다.

• 한국운동역학회지
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• 제13권1호
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• pp.1-12
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• 2003

The purpose of this study was to design the method of 3D space calibration to reduce RMSE by statistical analysis when using the DLT algorithm and control frame. Control frame for 3D space calibration was consist of $1{\times}3{\times}2m$ and 162 contort points adhere to it. For calculate of 3D coordination used two methods about 2D coordination on image frame, 2D coordinate on each image frame and mean coordination. The methods of statistical analysis used one-way ANOVA and T-test. Significant level was ${\alpha}=.05$. The compose of methods for reduce RMSE were as follow. 1. Use the control frame composed of 24-44 control points arranged equally. 2. When photographing, locate control frame to center of image plane(image frame) o. use the lens of a few distortion. 3. When calculate of 3D coordination, use mean of 2D coordinate obtainable from all image frames.

• 터널과지하공간
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• 제26권4호
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• pp.327-337
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• 2016

본 연구에서는 화강암 내부의 미세균열 분포에 따른 이방성이 수압파쇄실험 결과에 미치는 영향을 평가하였다. 압력증가율을 일정하게 설정하여 수압파쇄실험을 수행한 결과, 원주방향(주입정 방향과 직교)으로 리프트면이 분포한 시료의 파쇄압력이 가장 낮게 측정되었고, 이는 미세균열의 밀도가 높기 때문이다. 수압파쇄실험과정에서 시료 내부의 변화가 발생하는 주입압력의 크기와 유체 주입속도의 변화 또한 결방향에 따라 분포한 미세균열의 밀도와 관계가 있는 것으로 판단된다. 유체주입속도를 일정하게 설정하여 수압파쇄실험을 수행하였을 경우, 상대적으로 미세균열의 밀도가 높은 리프트면이 원주방향으로 분포된 시료에서 주입압력증가율이 낮게 나타났고, 유체가 침투될 수 있는 균열망이 상대적으로 적게 형성된 그레인면 및 하드웨이면이 원주방향으로 분포된 시료에서는 압력증가율이 높게 나타났다. X-ray CT 촬영을 통해 시료 내부에 생성된 균열의 방향을 확인한 결과, 대부분의 시료에서 리프트면 혹은 그레인면과 평행한 방향으로 균열이 생성된 것을 확인하였고, 이는 암석 내에 상대적으로 미세균열의 밀도가 높아서 분리성이 크기 때문이다.

• 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.