• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.117.1-117.1
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• 2011

We present the smoothness of mid-infrared sky brightness from the Japanese infrared astronomical satellite, AKARI observations. AKARI monitored the north ecliptic pole (NEP) during its cold phase with nine wavebands from 2.4 to 24 ${\mu}m$, out of which six mid-infrared bands are used in this study. Simple sinusoidal fit to the seasonal variation of the sky brightness shows that the mid-infrared brightness towards the NEP is not affected by small-scale features of the interplanetary dust cloud. We applied the power spectrum analysis to the images to search for the fluctuation of sky brightness. The fluctuation powers at 200 arcsecond are estimated to be at most $1.58{\pm}0.33\;nW\;m^{-2}sr^{-1}$ or 0.13% of the total brightness at $7{\mu}m$ and a tleast $0.64{\pm}0.11\;nW\;m^{-2}sr^{-1}$ or 0.02% at $18{\mu}m$. The residual fluctuations at a few arcminute scales at short mid-infrared wavelengths (7, 9, and 11 ${\mu}m$) are consistent with those expected from the diffuse galactic light. At long mid-infrared wavelengths (15, 18, and 24 ${\mu}m$) the measured fluctuations are comparable to or smaller than the one caused by photon noise and their sources are not identified. We conclude that the upper limit of the fluctuation in the zodiacal light is about 0.02% of the sky brightness.

• Journal of Korean Society for Geospatial Information Science
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• v.8 no.1 s.15
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• pp.85-95
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• 2000

There is a recent emphasis on the need for updating and revision of existing digital maps as more digital maps are used and produced. Various type of data sources, such as photographs, ground surveyed data and satellite images, are used in the revision and the updating process. The process is very time consuming and costly, especially for small regional areas. This study, attempts to present an effective update/revision method using the as-built surveying drawings and the accuracy of the digital map which has been updated and revised using this method was also investigated. This study showed that by using as-built surveying drawings of scale 1/1,200 to update a digital map of scale 1/1,000, the resulting accuracy satisfied the requirements of the national digital map accuracy specification for the corresponding scale. The necessity of the existence of the necessary drawings and maps is a requirement of this process and it is also suggested that densification of local control points especially in the urban areas is necessary for producing accurate as-built surveying drawings. This would require the establishment of rules and regulations which would require constructions to perform as-built surveying, immediately after the construction has been completed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.941-944
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• 2015

In this paper study for VSAT(very small aperture terminal) LNB(low noise block). ship LNB was demanded high stability and low noise figure. We designed FEM(Front-End Module) that was operated multi-band. FEM designed was constructed in a multi-band low noise receiver amplifier, a frequency converter, IF amplifier, Voltage Control Oscillator signal generating circuit four circuit using. To convert the multi-band 2.05GHz band, it generates four local oscillator signals, the four(band1, band2, band3, band4) designed to output an IF signal developed conversion apparatus, the conversion gain 64dB, noise figure 1dB or less, output P1dB 15dBm or more, phase noise showed -73dBc@100Hz.

• Genomics & Informatics
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• v.11 no.2
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• pp.76-82
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• 2013

Over the past decade or so, dramatic developments in our ability to experimentally determine the content and function of genomes have taken place. In particular, next-generation sequencing technologies are now inspiring a new understanding of bacterial transcriptomes on a global scale. In bacterial cells, whole-transcriptome studies have not received attention, owing to the general view that bacterial genomes are simple. However, several recent RNA sequencing results are revealing unexpected levels of complexity in bacterial transcriptomes, indicating that the transcribed regions of genomes are much larger and complex than previously anticipated. In particular, these data show a wide array of small RNAs, antisense RNAs, and alternative transcripts. Here, we review how current transcriptomics are now revolutionizing our understanding of the complexity and regulation of bacterial transcriptomes.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.125.1-125.1
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• 2012

The wave number 4 (wave-4) and wave number 3 (wave-3) longitudinal structures in the thermospheric neutral mass density are understood as tidal structures driven by diurnal eastward-propagating zonal wave number 3 (DE3) and wave number 2 (DE2) tides, respectively. However, those structures have been identified using data from limited time periods, and the consistency and recurrence of those structures have not yet been examined using long-term observation data. We examine the persistence of those structures by analyzing the neutral mass density data for the years 2001-2008 taken by the CHAllenging Minisatellite Payload (CHAMP) satellite. During years of low solar activity, the amplitude of the wave-4 structure is pronounced during August and September, and the wave-4 phase shows a consistent eastward phase progression of $90^{\circ}$ within 24 h local time in different months and years. During years of high solar activity, the wave-4 amplitude is small and does not show a distinctive annual pattern, but the tendency of the eastward phase shift at a rate of $90^{\circ}$/24 h exists. Thus the DE3 signature in the wave-4 structure is considered as a persistent feature. The wave-3 structure is a weak feature in most months and years. The amplitude and phase of the wave-3 structure do not show a notable solar cycle dependence. Among the contributing tidal modes to the wave-3 structure, the DE2 amplitude is most pronounced. This result may suggest that the DE2 signature, although it is a weak signature, is a perceivable persistent feature in the thermosphere.

• Korean Journal of Optics and Photonics
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• v.22 no.6
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• pp.283-290
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• 2011

A Raman LIDAR system has been designed and constructed for quantitative measurement of water vapor mixing ratio. The comparison with commercial microwave radiometer and global navigation satellite system(GNSS) was performed for the precipitable water vapor(PWV) profile and total PWV. The result shows that the total GNSS-PWV and LIDAR-PWV have good correlation with each other. But, there is small difference between the two methods because of maximum measurement height in LIDAR and the GNSS method. There are some significant differences between Raman and MWR when the water vapor concentration changes quickly near the boundary layer or at the edge of a cloud. Finally we have decided that MWR cannot detect spatial changes but LIDAR can measure spatial changes.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.64.1-64.1
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• 2011

MIRIS (Multipurpose Infra-Red Imaging System), is a small infrared space telescope which is being developed by KASI, as the main payload of Science and Technology Satellite 3 (STSAT-3). Two wideband filters (I and H) of the MIRIS enables us to study the cosmic infrared background by detecting the absolute background brightness. The narrow band filter for Paschen ${\alpha}$ emission line observation will be employed to survey the Galactic plane for the study of warm ionized medium and interstellar turbulence. The opto-mechanical design of the MIRIS is optimized to operate around 200K for the telescope, and the cryogenic temperature around 90K for the sensor in the orbit, by using passive and active cooling technique, respectively. The engineering and qualification model of the MIRIS has been fabricated and successfully passed various environmental tests, including thermal, vacuum, vibration and shock tests. The flight model was also assembled and is in the process of system optimization to be launched in 2012 by a Russian rocket. The mission operation scenario and the data reduction software is now being developed. After the successful mission of FIMS (the main payload of STSAT-1), MIRIS is the second Korean space telescope, and will be an important step towards the future of Korean space astronomy.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.7
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• pp.118-126
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• 2003

In this study, a battery charge and discharge regulator of modular type is designed as paralleled bi-directional converter that is possible to provide the power without failure not only in the steady state but also in the transient period by the step load variation or the unexpected faults among the converter modules. Each converter module is designed to get stability, performance, reliability, and maintainability and the average current mode method used for controller has the advantages such as noise immunity, fast response, and the real average current signal acquisition. The equivalent model and small signal model for the paralleled battery chargerIdischarger are presented, and also the transfer functions are analyzed for the CCM(Continuous Charge Mode), CDM(Continuous Discharge Mode) and DDM(Discontinuous Discharge Mode). The experiments of the paralleled bi-directional converter are carried out in the step load variation, and in faults of one converter module respectively. And the performance of paralleled bi-directional converter is verified via the experimental results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.10
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• pp.1017-1026
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• 2009

The solar cell system operates by facing the sun-light. Minor cracks, static discharge, and thermal shock that can happen during production/testing phase can lead to degradation in performance during operation, since solar cells are exposed to extreme thermal/mechanical environment in space. In order to detect small cracks and internal damages in the solar cells due to thermal shocks, which are the core units of a solar cell system, expensive equipment, complicated test process, and much time are required. Therefore, a qualitative method for easily and quickly testing the 'health' of solar cell functionality is required. This dissertation describes a theoretical and technical grounds for quickly and easily evaluating the health of solar cells using electroluminescence effect of Gallium-Arsenide solar cells that are most widely used by spacecrafts in recent years. Also described in the dissertation is the technical issues and constraining factors for applying the proposed method to actual space-rated solar cell systems.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.4
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• pp.337-344
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• 2004

A real-time surveillance system of the inshore fishing ground was constructed to identify and detect discrete targets, such as illegal fishing vessels. This paper describes measurements made with a combination of sensors, such as radar, CCTV camera, and GPS receivers, for monitoring the fishing activity of small vessels within the fishing limit zones of the inshore waters. The CCTV camera system was used to confirm detection and to classify the type of target. The location of legal vessels distributed in coastal waters was acquired from each GPS system of ships connected to commercial satellite communication network. The surveillance system was networked via LAN to one host PC with the use of electronic navigational charts (ENC) and a radar link. Radar Target Extractor (RTX) for radar signal processing can be remotely accessed and controlled on existing PC via the internet, from anywhere, at any time. Results are presented that demonstrate the effectiveness of the newly constructed fisheries monitoring system for conducting continuous surveillance of illegal fishing vessels in the inshore fishing ground. The identification of illegal fishing vessels was achieved by comparing radar positions of illegal fishing vessels exceeding the warning limits in the surveillance area with GPS position reports transmitted from legal fishing vessels, and the illegal fishing vessels were marked with red symbols on the ENC screen of a PC. The methods to track the activities of all vessels intruding or leaving the fishing limit zones also were discussed.