• Journal of the Korean earth science society
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• v.43 no.1
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• pp.1-22
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• 2022

We provide a detailed description of the installation and operation of a remote spectroscopic meteor observation system at Unjangsan optical astronomy observatory. Three light-sensitive charge-coupled device cameras were installed, and two cameras had a diffraction grating attached to the front of the lens. Station employ sensitive "Watec-902H2" cameras in combination with f/1.2 lenses were installed in November 2019. Diffraction gratings for spectral observations were used at 500 l/mm. Observations were conducted from November 2019 to June 2020. We employed the SonotaCo UFO software suite for meteor detection. Subsequently, meteor spectra were analyzed using field-tested RSpec software. To analyze the observation images, astronomical calibration and photometric calibration were performed, and the chemical elements of the meteor were determined. The study results are presented along with the system setup installation and operation experience. Brief information regarding the origin of the meteor was also provided based on the results.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.116-119
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• 2009

HSPF is a comprehensive, continuous, lumped parameter, watershed-scale model that simulates the movement of water, sediment, and a wide range of water quality constituents on pervious and impervious surfaces, in soil profiles, and within streams and well-mixed reservoirs. The hydrologic calibration of HSPF is performed manually using the decision-support software Expert System for the Calibration of HSPF (HSPEXP). The initial values for the HSPF hydrologic parameters were estimated based on guidance from BASINS Technical Note 6. Initial parameter values were adjusted for the study watershed during the calibration period within the recommended ranges for the parameters.

• Applied Microscopy
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• v.46 no.2
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• pp.71-75
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• 2016

The scanning electron microscope (SEM) offers two-dimensional (2D) micrographs of three-dimensional (3D) objects due to its inherent operating mechanisms. To overcome this limitation, other devices have been used for quantitative morphological analysis. Many efforts have been made on the applications of software-based approaches to 3D reconstruction and measurements by SEM. Based on the acquisition of two stereo images, a multi-view technique consists of two parts: (i) geometric calibration and (ii) image matching. Quantitative morphological parameters such as height and depth could be nondestructively measured by SEM combined with special software programs. It is also possible to obtain conventional surface parameters such as roughness and volume of biomedical specimens through 3D SEM surface reconstruction. There is growing evidence that conventional 2D SEM without special electron detectors can be transformed to 3D SEM for quantitative measurements in biomedical research.

• Korean Journal of Remote Sensing
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• v.38 no.5_1
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• pp.485-496
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• 2022

This study is for the software implementation to generate atmospheric and surface reflectance products from RapidEye satellite imagery. The software is an extension based on Orfeo Toolbox (OTB) and an open-source remote sensing software including calibration modules which use an absolute atmospheric correction algorithm. In order to verify the performance of the program, the accuracy of the product was validated by a test image on the Radiometric Calibration Network (RadCalNet) site. In addition, the accuracy of the surface reflectance product generated from the KOMPSAT-3A image, the surface reflectance of Landsat Analysis Ready Data (ARD) of the same site, and near acquisition date were compared with RapidEye-based one. At the same time, a comparative study was carried out with the processing results using QUick Atmospheric Correction (QUAC) and Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) tool supported by a commercial tool for the same image. Similar to the KOMPSAT-3A-based surface reflectance product, the results obtained from RapidEye Extension showed accuracy of agreement level within 5%, compared with RadCalNet data. They also showed better accuracy in all band images than the results using QUAC or FLAASH tool. As the importance of the Red-Edge band in agriculture, forests, and the environment applications is being emphasized, it is expected that the utilization of the surface reflectance products of RapidEye images produced using this program will also increase.

• The Journal of Korea Robotics Society
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• v.11 no.1
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• pp.9-18
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• 2016

A rectangle-based relative localization method is proposed for a mobile robot based on a novel geometric formulation. In an artificial environment where a mobile robot navigates, rectangular shapes are ubiquitous. When a scene rectangle is captured using a camera attached to a mobile robot, localization can be performed and described in the relative coordinates of the scene rectangle. Especially, our method works with a single image for a scene rectangle whose aspect ratio is not known. Moreover, a camera calibration is unnecessary with an assumption of the pinhole camera model. The proposed method is largely based on the theory of coupled line cameras (CLC), which provides a basis for efficient computation with analytic solutions and intuitive geometric interpretation. We introduce the fundamentals of CLC and describe the proposed method with some experimental results in simulation environment.

• Journal of Biosystems Engineering
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• v.24 no.2
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• pp.159-166
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• 1999

A system to extract continuously the real 3-D geometric fearture information from 2-D image of an object, which is fed randomly via conveyor has been developed. Two sets of structured laser lightings were utilized. And the laser structured light projection image was acquired using the camera from the signal of the photo-sensor mounted on the conveyor. Camera coordinate calibration matrix was obtained, which transforms 2-D image coordinate information into 3-D world space coordinate using known 6 points. The maximum error after calibration showed 1.5 mm within the height range of 103mm. The correlation equation between the shift amount of the laser light and the height was generated. Height information estimated after correlation showed the maximum error of 0.4mm within the height range of 103mm. An interactive 3-D geometric feature extracting software was developed using Microsoft Visual C++ 4.0 under Windows system environment. Extracted 3-D geometric feature information was reconstructed into 3-D surface using MATLAB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.11
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• pp.2191-2198
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• 2017

The PME(precision measurement equipment) used in the measurement to check the performance of the equipment in military weapon system is periodically calibrated to maintain measurement reliability during the life cycle. Previous studies suggest that reliability models are determined by considering sample size and characteristics of equipment. However, it may not be fit well to apply a single model assuming the same characteristic distribution for the maintenance date of many kinds of PMEs. This paper proposes that the most suitable calibration interval for maintenance data is selected through the F-test and the performance index evaluation among the calibration intervals estimated from the measurement reliability models assuming the characteristic of the bath-tub curve during the life cycle of various PMEs. The research results show that the reliabilities of various types of equipment are maintained during calibration intervals.

• The Journal of the Acoustical Society of Korea
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• v.41 no.1
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• pp.1-8
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• 2022

This paper identifies the cause of the high frequency calibration limit of the acoustic chamber type calibrator for microphone calibration and presents a method to improve it. By using a commercial finite element analysis software, we analyzed the calibration frequency limit of the acoustic chamber type calibrator through eigen-frequency and frequency domain analysis. Based on this, we designed and fabricated an acoustic chamber type calibrator that can precisely calibrate within 1 dB from about 2 Hz to 6.4 kHz and verified its performance through experiments. The acoustic chamber type calibrator fabricated through this study has the advantage of being able to calibrate multiple microphones simultaneously in a wide frequency range, so it can be usefully used for simple calibration for multiple microphones.

• Communications for Statistical Applications and Methods
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• v.25 no.2
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• pp.131-157
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• 2018

We propose a robust event date model to estimate the date of a target event by a combination of individual dates obtained from archaeological artifacts assumed to be contemporaneous. These dates are affected by errors of different types: laboratory and calibration curve errors, irreducible errors related to contaminations, and taphonomic disturbances, hence the possible presence of outliers. Modeling based on a hierarchical Bayesian statistical approach provides a simple way to automatically penalize outlying data without having to remove them from the dataset. Prior information on individual irreducible errors is introduced using a uniform shrinkage density with minimal assumptions about Bayesian parameters. We show that the event date model is more robust than models implemented in BCal or OxCal, although it generally yields less precise credibility intervals. The model is extended in the case of stratigraphic sequences that involve several events with temporal order constraints (relative dating), or with duration, hiatus constraints. Calculations are based on Markov chain Monte Carlo (MCMC) numerical techniques and can be performed using ChronoModel software which is freeware, open source and cross-platform. Features of the software are presented in Vibet et al. (ChronoModel v1.5 user's manual, 2016). We finally compare our prior on event dates implemented in the ChronoModel with the prior in BCal and OxCal which involves supplementary parameters defined as boundaries to phases or sequences.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.54.1-54.1
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• 2015

We report results of investigation of amplitude calibration for very long baseline interferometry (VLBI) observations with Korean VLBI Network (KVN). Amplitude correction factors are estimated based on comparison of KVN observations at 22 GHz correlated by Daejeon hardware correlator and DiFX software correlator in Korea Astronomy and Space Science Institue (KASI) with Very Long Baseline Array (VLBA) observations at 22 GHz by DiFX software correlator in National Radio Astronomy Observatory (NRAO). We used the observations for compact radio sources, 3C 454.3 and NRAO 512 which are almost unresolved for baselines in a range of 350-477 km. VLBA visibility data of the sources observed with similar baselines as KVN are selected, fringe-fitted, calibrated, and compared in their amplitudes. We found that visibility amplitudes of KVN observations should be corrected by factors of 1.14 and 1.40 when correlated by DiFX and Daejeon correlators, respectively. These correction factors are attributed to the combination of two steps of 2-bit quantization in KVN observing systems and characteristics of Daejeon correlator.