• Journal of Astronomy and Space Sciences
• /
• v.3 no.1
• /
• pp.41-51
• /
• 1986

Two-photometric light curves(Oh and Chen 1984) of the eclipsing binary TX UMa have been analyzed by the method of differential corrections of the model of Wilson and Devinney (1971). The system found to be simi-detached with the cooler and less massive component filling its Roche lobe. The absolute dimensions have been derived from the results of the photometric solutions with the spectroscopic elements of Hiltner(1945). It is assumed that the B8V primary component is on the zero main sequence stage of the core hydrogen burning and the secondary is at the core contraction stage after the shell hydrogen burning stage according to the Iben's (1967) evolutional tracks for $3.0m_\odot$ and $1.0m_\odot$ .

• YAKHAK HOEJI
• /
• v.34 no.3
• /
• pp.215-218
• /
• 1990

An ion chromatographic method based on indirect photometric detection of UV transparent anions was developed. Separation of anion was accomplished on strong anion exchange column (Waters SAX) using UV detector at 254 nm. Among examined UV-active additives (Dns-H, Dns-glu, Dnsser, Dns-val), Dns-glu showed the highest sensitivity. Studies on the effects of the pH and ionic strength of eluent revealed that the increase of pH and ionic strength of the eluent decreased capacity factor. The best eluent for the separation of acetate, fluoride, chloride, nitrate and bromide was $1\;{\times}\;10^{-4}M$ Dns-glu in 5 mM phosphate buffer (pH 6.30). The detection limit of chloride ion was 2.1 ng in this condition.

• Journal of Institute of Control, Robotics and Systems
• /
• v.19 no.12
• /
• pp.1061-1066
• /
• 2013

In the steel industry, the detection of tiny defects including its 3D characteristics on steel surfaces is very important from the point of view of quality control. A multi-spectral photometric stereo method is an attractive scheme because the shape of the defect can be obtained based on the images which are acquired at the same time by using a multi-channel camera. Moreover, the calculation time required for this scheme can be greatly reduced for real-time application with the aid of a GPU (Graphic Processing Unit). Although a more reliable shape reconstruction of defects can be possible when the numbers of available images are increased, it is not an easy task to construct a camera system which has more than 3 channels in the visible light range. In this paper, a new 6-channel camera system, which can distinguish the vertical/horizontal linearly polarized lights of RGB light sources, was developed by adopting two 3-CCD cameras and two polarized lenses based on the fact that the polarized light is preserved on the steel surface. The photometric stereo scheme with 6 images was accelerated by using a GPU, and the performance of the proposed system was validated through experiments.

• Journal of The Korean Astronomical Society
• /
• v.24 no.2
• /
• pp.151-159
• /
• 1991

Using the photographic imagery of the SO galaxy NGC 5102, the equivalent luminosity profile and the fractional integrated luminosity curve have been derived. Several photometric parameters of the galaxy, such as a total magnitude ($B_T$), equivalent radius ($r^*_e$), effective surface brightness (${\mu}^*_e$), and concentration indices ($C_{21}$, $C_{32}$) were derived from the luminosity profiles. According to the decomposition method from the nonlinear least squares fitting, photometric parameters of the bulge (${\mu}_e$, $r_e$) and the exponential disk (${\mu}(0)$, ${\alpha}^{-1}$), and the bulge to total luminosity ratio (B/T) were obtained. The derived central disk surface brightness (${\mu} (0)\;=\;22.06\;{\pm}\;0.18\;mag/\Box"$) and the evaluated B/T ratio (= 0.52) of the NGC 5102 are close to the mean values (${\mu} (0)\;=\;21.65\;{\pm}\;0.3\;mag/\Box"$, B/T=0.63) of the SO galaxies. Analysis showed that a lens-like hump is embedded in the equivalent luminosity profile of the NGC 5102.

• Korean Journal of Food Science and Technology
• /
• v.37 no.5
• /
• pp.695-701
• /
• 2005

Efficient method was established for analysis of sulfur-containing compounds, including dimethyl disulfide, dimethyl trisulfide, 3-methyl thiophene, allyl mercaptan, 2-methyl-3-furanthiol, and methional. Sulfur-containing compounds were extracted through solid phase microextraction (SPME) or static headspace extraction (SH), and quantified using gas chromatograph equipped with pulsed flame photometric detector. All sulfur compounds, except ally mercaptan, showed higher detection response when dissolved in hexane than in dichloromethane. Linear range was $10^2-10^4$. Dimethyl trisulfide showed lowest limit of detection (LOD) value of 15.2 ppt, and methional highest of 70.5 ppb. Highest extraction efficiency for sulfur-containing compounds, particularly polar and small molecular weight compounds, was observed in 75mm carboxen/polydimethylsiloxane fiber, followed by 65mm polydimethylsiloxane/divinylbenzene and 100mm polydimethylsiloxane. Compared to SPME, less sulfur-containing compounds could be analyzed by SH, mainly due to its low extraction efficiency, although lower amount of artifacts were formed during sample preparation.

• Journal of The Korean Astronomical Society
• /
• v.49 no.5
• /
• pp.175-192
• /
• 2016

CCD photometric observations of the globular cluster (GC), M53 (NGC 5024), are performed using the 1.8 m telescope at the Bohyunsan Optical Astronomy Observatory in Korea on the same nights (2002 April and 2003 May) as the observations of the GC M92 (NGC 6341) reported by Cho and Lee using the same instrumental setup. The data for M53 is reduced using the same method as used for M92 by Cho and Lee, including preprocessing, point-spread function fitting photometry, and standardization etc. Therefore, M53 and M92 are on the same photometric system defined by Landolt, and the photometry of M53 and M92 is tied together as closely as possible. After complete photometric reduction, the V versus B − V , V versus V − I, and V versus B − I color-magnitude diagrams (CMDs) of M53 are produced to derive the relative ages of M53 and M92 and derive the various characteristics of its CMDs in future analysis. From the present analysis, the relative ages of M53 and M92 are derived using the Δ(B − V ) method reported by VandenBerg et al. The relative age of M53 is found to be 1.6 ± 0.85 Gyr younger than that of M92 if the absolute age of M92 is taken to be 14 Gyr. This relative age difference between M53 and M92 causes slight differences in the horizontal-branch morphology of these two GCs.

• Journal of Astronomy and Space Sciences
• /
• v.30 no.4
• /
• pp.327-334
• /
• 2013

The purpose of this study is to develop an observation program for obtaining effective flat images that are necessary for photometric observation. The development of the program was achieved by improving the existing method for obtaining twilight flat images. The existing method for obtaining twilight flat images acquires flat images by observing the sky light after sunset or light before sunrise. The decision of when to observe flat images at each night is solely dependent on the judgment of an observer, and thus the obtained flat images for particular nights may not be clean. Especially, in the case of the observatories where an automated observation system is in operation, there is a difficulty that an observer should pay attention during sunrise and sunset in order to obtain flat images. In this study, a computer program is developed to improve this inconvenience and to efficiently perform photometric observation in the observatories where an automated observation system is applied. This program can obtain flat images by calculating the time for obtaining flat images automatically and the exposure time using a numerically calculated function. When obtaining twilight flat images at dusk and at dawn, the developed program performs automated observation and provides effective flat images by acquiring appropriate exposure time considering the sunrise and sunset times that vary depending on the day of observation. The code for performing this task was added to Obs Tool II (Yoon et al. 2006), which is the automated observation system of the Chungbuk National University Observatory, and the usefulness of the developed program was examined by performing an actual automated observation. If this program is applied to other observatories where automated observation is in operation, it is expected that stable and high-quality flat images could be obtained, which can be used for the pre-processing of photometric observation data.

• Publications of The Korean Astronomical Society
• /
• v.26 no.4
• /
• pp.159-168
• /
• 2011

We constructed two test server systems for KMTNet data management. One is the photometry database server which is optimized for stable operation, and the other is the photometric data process server which is optimized for fast I/O between devices. The performances of servers and data storage units were tested using various methods. Database upload was also checked using five different methods. From tests, we concluded that the most efficient method to upload photometric data processing results to database is the use of three nodes with job scheduler under the InnoDB engine. In this study we provide the test results for prototype servers for KMTNet data management.

• The Bulletin of The Korean Astronomical Society
• /
• v.38 no.1
• /
• pp.52.2-52.2
• /
• 2013

We compile a near-infrared photometric and polarimetric catalog for the $5{\times}9$ fields (${\sim}39^{\prime}{\times}69^{\prime}$) in the eastern side of the Large Magellanic Cloud (LMC). The photometric and the polarimetric data were obtained in J, H, and Ks bands using JHKs-simultaneous imaging polarimeter SIRPOL of the InfraRed Survey Facility (IRSF) in 2008 December and 2011 December. We estimate quality of the data using the method and the result from the IRSF Magellanic Clouds point source catalog which was published on 2007 June. In this poster, we present configuration of the catalog and the results of the verification.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.17 no.4
• /
• pp.209-215
• /
• 2022

This paper proposes a novel approach for training an unsupervised depth estimation algorithm. The objective of unsupervised depth estimation is to estimate pixel-wise distances from camera without external supervision. While most previous works focus on model architectures, loss functions, and masking methods for considering dynamic objects, this paper focuses on the training framework to effectively use depth cue. The main loss function of unsupervised depth estimation algorithms is known as the photometric error. In this paper, we claim that direct depth cue is more effective than the photometric error. To obtain the direct depth cue, we adopt the technique of knowledge distillation which is a teacher-student learning framework. We train a teacher network based on a previous unsupervised method, and its depth predictions are utilized as pseudo labels. The pseudo labels are employed to train a student network. In experiments, our proposed algorithm shows a comparable performance with the state-of-the-art algorithm, and we demonstrate that our teacher-student framework is effective in the problem of unsupervised depth estimation.