• Journal of Biosystems Engineering
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• 제39권4호
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• pp.352-356
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• 2014

Purpose: We estimated the dietary qualities of green soybean (edamame) by using a specialized NIR transmission spectrometer to determine the constitutive properties of the soybean, such as the sucrose content and ninhydrine reaction quantity (NRQ; defined by the ninhydrine reaction, which has a high positive correlation with the total free amino acids), with the purpose of establishing a quality assurance system. Methods: We used a newly developed spectrometer probe that enables in situ estimation of the constituents of the soybean. Results: The calibration results obtained using a wavelength range of 760-960 nm were characterized by $R^2$ = 0.57 and standard error of cross-validation (SECV) of 0.78% for sucrose, and $R^2$ = 0.59 and SECV = 0.35% for NRQ. Conclusions: These results are inferior to those of our previous study obtained using a specialized bench-type transmission spectrometer. The poorer results are attributed to several possible reasons, including the effect of direct sunlight and the unstable sample presentation. We plan to conduct further study using improved optical layout and sample presentation.

• 항공우주산업기술동향
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• 제6권2호
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• pp.80-89
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• 2008

사진측정기는 2차원 사진 이미지를 사용해 비접촉식으로 3차원 좌표를 측정한다. 사진측정기는 2차원 사진으로부터 3차원 데이터를 재구성하기 위해 삼각측량법을 사용한다. 디지털 사진측정기는 측정사진에 대한 맵핑(mapping)과 비율 조정(scaling) 그리고 번들(bundle) 조정이 소프트웨어로 동시에 계산되며 이를 통해 카메라의 위치와 좌표를 해석해 낸다. 본 연구에서는 대형전파망원경의 구조적인 변형 측정, ISIM 시험 구조체의 사진측정기 결과 분석, 원자로 연료 조립물에 대한 수중 사진측정, 위성 광학 조립부 측정 및 위성 지상지원장비 측정과 같은 특별한 용도로 사용된 사진 측정기에 대해 소개하였다.

• 한국정밀공학회지
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• 제20권6호
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• pp.88-95
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• 2003

This paper presents the measurement and correction method of PCB alignment errors for PCB screen printer. Electronic equipment is getting smaller and yet must satisfy high performance standard. Therefore, there is a great demand for PCB with high density. However conventional PCB screen printer doesn't have enough accuracy to accommodate the demand fur high-resolution circuit pattern and high-density mounting capacity of electronic chips. It is because the alignment errors of PCB occur when it is loaded to the screen printer. Therefore, this study focuses on the development of the system which is able to measure and correct alignment errors with high-accuracy. An automatic optical inspection part measures the PCB alignment errors using machine vision, and the high-accuracy 3-axis stage makes correction for these errors. This system used two CCD cameras to get images of two fiducial marks of PCB. The geometrical relationship between PCB, cameras, and xy$\theta$ stage is derived, and analytical equations for alignment errors are also obtained. The unknown parameters including camera declining angles and etc. can be obtained by initialization process. Finally, the proposed algorithm is verified by experiments by using test bench.

• 천문학회지
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• 제56권2호
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• pp.169-185
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• 2023

The GMT-Consortium Large Earth Finder (G-CLEF) is the first instrument for the Giant Magellan Telescope (GMT). G-CLEF is a fiber feed, optical band echelle spectrograph that is capable of extremely precise radial velocity measurement. G-CLEF Flexure Control Camera (FCC) is included as a part in G-CLEF Front End Assembly (GCFEA), which monitors the field images focused on a fiber mirror to control the flexure and the focus errors within GCFEA. FCC consists of an optical bench on which five optical components are installed. The order of the optical train is: a collimator, neutral density filters, a focus analyzer, a reimager and a detector (Andor iKon-L 936 CCD camera). The collimator consists of a triplet lens and receives the beam reflected by a fiber mirror. The neutral density filters make it possible a broad range star brightness as a target or a guide. The focus analyzer is used to measure a focus offset. The reimager focuses the beam from the collimator onto the CCD detector focal plane. The detector module includes a linear translator and a field de-rotator. We performed thermoelastic stress analysis for lenses and their mounts to confirm the physical safety of the lens materials. We also conducted the global structure analysis for various gravitational orientations to verify the image stability requirement during the operation of the telescope and the instrument. In this article, we present the opto-mechanical detailed design of G-CLEF FCC and describe the consequence of the numerical finite element analyses for the design.

• Journal of Advanced Marine Engineering and Technology
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• 제39권1호
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• pp.32-44
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• 2015

일반적으로 선박의 운동은 이동운동과 회전운동의 결합으로 이루어진다. 특히 대형 크루즈 선박과 광케이블 포설용 선박, 다이버용 선박 등 특수 선박은 자동 접이안이나 설정된 경로 등을 따라 선수방향의 변화 없이 여러 방향으로 이동만 하는 운동을 재현할 수 있어야 한다. 본 논문에서는 다 추력장치를 가진 선박을 대상으로 조이스틱 명령 기반의 이동운동제어를 실현할 수 있는 통합제어시스템의 구성방법을 제안하며, 이를 실현하기 위하여 필요한 속도명령 생성방법과 대응하는 운동변수 및 이들이 가져야 하는 기준 값 생성방법을 제안한다. 또한 정의된 운동변수의 기준 값을 추종하기 위한 다양한 알고리즘 구성에 대하여 논한다. 또한 통합제어시스템 시뮬레이션 프로그램을 작성하고 이를 토대로 다양한 이동운동 명령에 대한 모의실험을 수행한 후, 시뮬레이션 결과를 바탕으로 제안된 방법의 유효성을 검증한다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.540-543
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• 2007

The modulation transfer function (MTF) in a camera system is a measurement of how well the system will faithfully reproduce the original scene. The electro-optical camera system consists of optics, an array of pixels, and an electronics which is related to the image signal chain. The system MTF can be cascaded with each element's MTF in the frequency domain. That is to say, the electronics MTF including the detector MTF can be recalculated easily by the acquired system MTF if the well-known test optics is used in the measuring process. A Time-Delay and Integration (TDI) detector can make a signal increase by taking multiple exposures of the same object and adding them. It can be considered the various methods to measure the MTF of the TDI camera system. This paper shows the actual and practical MTF measuring methods for the detector and electronics in the TDI camera. The several methods are described according to the scan direction as well as the TDI stages such as the single line mode and the multiple-lines mode. The measuring is performed in the in the static condition or dynamic condition to get the point spread function (PSF) or the line spread function (LSF). Especially, the dynamic test bench is used to simulate on track velocity to synchronize with TDI read out frequency for the dynamic movement.

• 천문학회보
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• 제39권1호
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• pp.53.2-53.2
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• 2014

IGRINS, the Immersion GRating INfrared Spectrometer, is a near-infrared wide-band high-resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. IGRINS employs three HAWAII-2RG focal plane array (FPA) detectors. The mechanical mounts for these detectors serves a critical function in the overall instrument design: Optically, they permit the only positional compensation in the otherwise "build to print" design. Thermally, they permit setting and control of the detector operating temperature independently of the cryostat bench. We present the design and fabrication of the mechanical mount as a single module. The detector mount includes the array housing, a housing for the SIDECAR ASIC, a field flattener lens holder, and a support base. The detector and ASIC housing will be kept at 65 K and the support base at 130 K. G10 supports thermally isolate the detector and ASIC housing from the support base. The field flattening lens holder attaches directly to the FPA array housing and holds the lens with a six-point kinematic mount. Fine adjustment features permit changes in axial position and in yaw and pitch angles. We optimized the structural stability and thermal characteristics of the mount design using computer-aided 3D modeling and finite element analysis. Based on the computer simulation, the designed detector mount meets the optical and thermal requirements very well.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4195-4208
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• 2022

In this study, operator habitability was numerically evaluated in the event of a fire at the main control bench board (MCB) in a reference main control room (MCR). It was investigated if evacuation variables including hot gas layer temperature (HGLT), heat flux (HF), and optical density (OD) at 1.8 m from the MCR floor exceed the reference evacuation criteria provided in NUREG/CR-6850. For a fire model validation, the simulation results of the reference MCR were compared with existing experimental results on the same reference MCR. In the simulation, various input parameters were applied to the MCB panel fire scenario: MCR height, peak heat release rate (HRR) of a panel, number of panels where fire propagation occurs, fire propagation time, door open/close conditions, and mechanical ventilation operation. A specialized-average HRR (SAHRR) concept was newly devised to comprehensively investigate how the various input parameters affect the operator's habitability. Peak values of the evacuation variables normalized by evacuation criteria of NUREG/CR-6850 were well-correlated as the power function of the SAHRR for the various input parameters. In addition, the evacuation time map was newly utilized to investigate how the evacuation time for different SAHRR was affected by changing the various input parameters. In the previous studies, it was found that the OD is the most dominant variable to determine the MCR evacuation time. In this study, however, the evacuation time map showed that the HF is the most dominant factor at the condition of without-mechanical ventilation for the MCR with a partially-open false ceiling, but the OD is the most dominant factor for all the other conditions. Therefore, the method using the SAHRR and the evacuation time map was very useful to effectively and comprehensively evaluate the operator habitability for the various input parameters in the event of MCB fires for the reference MCR.

• 대한토목학회논문집
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• 제26권2C호
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• pp.99-108
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• 2006

본 연구에서는 점성토의 강도를 증진시키기 위해, 일련의 동전기 주입 안정화 실내 실험을 수행하였다. 이를 위해 규산나트륨을 주입제로 선정하고 농도를 변화(500, 1000, 1500, 2000, 2500mM)시켜 동전기 주입 안정화 기법의 적용성을 파악하였고, 처리기간과 전압경사에 따른 영향을 파악하기 위해 2일 간격(2, 4, 6, 8, 10일)으로 처리기간을 설정한 실험과 0.25, 0.5, 1.0, 1.5, 2.0V/cm로 전압경사를 변화시킨 실험을 실시하였다. 또한 염화칼슘과 수산화알루미늄을 2차 주입제로 사용하여 첨가농도에 따른 전단강도 개량 효과를 파악하고자 하였다. 이를 위해 규산나트륨(1000mM)을 5일간 적용한 후 2차 주입제의 농도를 50, 250, 500, 750, 1000mM로 변화시켜 5일간 적용하였다. 규산나트륨의 농도 결정시험결과 1000mM 이상의 농도에서 일정한 값으로 수렴하는 양상을 띠었으며, 이 때 초기 강도보다 약 800% 크게 강도증진효과가 나타났다. 최적전기경사와 처리기간 결정시험결과 전압의 경우 1V/cm, 처리기간의 경우 6일 이상에서 강도증가치가 수렴하는 양상이 나타났다. 염화칼슘과 수산화알루미늄을 2차 주입제로 사용한 경우, 두 경우 모두 250mM 이상의 농도에서 일정한 강도값으로 수렴하는 양상이 나타났으며, 규산나트륨만 사용한 경우보다 약 20~30%의 강도증진효과가 발생했다.