• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.59-61
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• 2017

The AKARI 9 and 18 µm diffuse maps reveal the all-sky distribution of the interstellar medium with relatively high spatial resolution of ~6". The zodiacal light is a dominant foreground component in the mid-infrared. Thus, removal of the zodiacal light is a critical issue to study low surface brightness Galactic diffuse emission. We carried out modeling of the zodiacal light based on the Kelsall model which is constructed from the COBE data. In the previous study, only a time-varying component of the zodiacal light brightness was used for determination of the model parameters. However, there remains a residual component of the zodiacal light around the ecliptic plane even after removal with the model. Therefore, instead of using a time-varying component, we use the absolute brightness of the zodiacal light and we find that the new model can better remove the residual component. As a result, the best-fit model parameters are changed from those in the previous study. We discuss the properties of the zodiacal light based on our new result.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.1
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• pp.751-760
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• 2009

This research aims to develop the strategy and method to enhance the reliability of image matching results and improve the efficiency of the matching process by utilizing LIDAR data in the main image matching processes. In this work, we present the methods to utilize LIDAR data in the selection of matching entities, the search for the matched entities and the evaluation of the matching results. The proposed method has been applied to medium-resolution digital aerial images and LIDAR data acquired at the same time. The results have been analyzed in comparison with an existing method using a virtual horizontal surface rather than LIDAR DEM. This analysis indicates that the proposed method can show significantly more improved performance than the existing method. The results of this study can contribute to the improvement of the currently available commercial image matching software and the enhancement of the DEM derived from LIDAR data and matching results.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.355-362
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• 1999

With the ready access to the high resolution satellite image data, users of and areas covered by satellite image data are constantly on the rise world-wide. Korea will also be able to take full advantage of the satellite data once the KOMPSAT is successfully launched. Harmonizing satellite data production and application technology and users' needs, along with the guiding policy is essential for promoting satellite data use. Up to now, the Korean government has mainly concentrated on developing production technology for the satellite units. However, the imminent task of independent satellite data production demands a promotion policy for satellite data use. In this context, the policy is defined as an important medium for identifying the role and status of satellite image information at the national level and also Preparing the legal as well as systematic foundation for producing, building, distributing, and packaging satellite data. For example, in the countries with the advanced satellite technology, such as the United States, the United Kingdom, and Australia, digital ortho image and digital elevation model (DEM) are mandatorily included in the National Geographic Framework Data through policy measures. In addition, in order for the efficient provision of the satellite data, separate organization or agency is being in operation for the exclusive production and distribution of the satellite data. The present paper aims to examine the role and status of the satellite data as well as their current status and problems in Korea in reference to the National Spatial Data Infrastructure, and finally to provide the policy directions to promote the satellite data use in public sector on the basis of the preceding analyses.

• Journal of the Korean earth science society
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• v.31 no.5
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• pp.475-487
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• 2010

Sea surface wind field was retrieved from high-resolution SIR-C SAR data by using CMOD algorithms off the east coast of Korea. In order to extract wind direction information from SAR data, a two-dimensional spectral analysis method was applied to the normalized radar cross section of the image. An $180^{\circ}$-ambiguity problem in the determination of wind direction was solved by selecting a direction nearest to the wind vector of the ECMWF reanalysis data. Comparison of the wind retrieval patterns with the ECMWF and NCEP/NCAR dataset showed RMS errors in the range of 1.30 to $1.72\;ms^{-1}$. In contrast, comparison of wind directions revealed large errors of greater than $60^{\circ}$, which is enormously higher than the permitted limit of about $20^{\circ}$ for satellite scatterometer winds. Compared with wind speed results from different algorithms, wind vectors based on commonly-used CMOD4 algorithm showed good agreement with those derived by other algorithms such as CMOD_IFR2 and CMOD5, particularly at medium winds from 4 to $8\;ms^{-1}$. However, apparent discrepancy appeared at low winds (< $4\;ms^{-1}$). This study also addressed an importance of accurate wind direction data to improve the accuracy of wind speed retrieval and discussed potential causes of wind retrieval errors from SAR data.

• Atmosphere
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• v.28 no.1
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• pp.85-97
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• 2018

This study evaluates the performance of the Weather Research and Forecasting (WRF) model in reproducing the present-day (1981~2005) precipitation over Far East Asia and South Korea. The WRF model is configured with 25-km horizontal resolution within the context of the COordinated Regional climate Downscaling Experiment (CORDEX) - East Asia Phase 2. The initial and lateral boundary forcing for the WRF simulation are derived from European Centre for Medium-Range Weather Forecast Interim reanalysis. According to our results, WRF model shows a reasonable performance to reproduce the features of precipitation, such as seasonal climatology, annual and inter-annual variabilities, seasonal march of monsoon rainfall and extreme precipitation. In spite of such model's ability to simulate major features of precipitation, systematic biases are found in the downscaled simulation in some sub-regions and seasons. In particular, the WRF model systematically tends to overestimate (underestimate) precipitation over Far East Asia (South Korea), and relatively large biases are evident during the summer season. In terms of inter-annual variability, WRF shows an overall smaller (larger) standard deviation in the Far East Asia (South Korea) compared to observation. In addition, WRF overestimates the frequency and amount of weak precipitation, but underestimates those of heavy precipitation. Also, the number of wet days, the precipitation intensity above the 95 percentile, and consecutive wet days (consecutive dry days) are overestimated (underestimated) over eastern (western) part of South Korea. The results of this study can be used as reference data when providing information about projections of fine-scale climate change over East Asia.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.1
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• pp.22-33
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• 1991

The studies aimed to distinguish between initial (ionic or osmotic) effects of salinisation on growth and the longer-term consequences of excessive salt accumulation. Tall and dwarf varieties of rice were used to provide different growth rates. There was no significant effect upon the day-to-day pattern of growth, upon the ultimate length of leaves that were developing at the time of, or shortly after, salinisation with 50 mM NaCl. Leaves that developed after prolonged exposure of the plants to salinity were shorter. Addition of NaCl, KCl or mannitol to the root medium brought about a cessation of leaf elongation within one minute. Growth at a reduced rate restarted abruptly after a lag period that depended upon the external concentration. Elongation rate recovered to its original value within 24 hours after exposure to 50 mM NaCl, though not at higher concentrations. Addition of NaCl at concentrations up to 100 mM elicited no short-term effect upon photsynthetic gas exchange. No change in turgor pressure was detectable in the growing zone with the resolution of the miniature pressure probe used (about 70 kPa). It is concluded that the initial growth reduction in rice caused by salinisation is due to a limitation of water supply. A clear distinction is made between the initial effects of salt which are recoverable, and the long-term effects which result from the accumulation of salt within expanded leaves.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.2
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• pp.110-119
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• 2013

As the technologies such as middle-range resonant WPT (wireless power transfer) advance that utilizes medium and low-frequency magnetic field, the importance of safety of such magnetic field is growing. The research on the effect of electromagnetic field on the human body has been mainly done on the GHz range of mobile phones, or 50~60Hz range of electric power systems. However, there has been relatively few works on the 100kHz~10MHz range used in the resonant wireless power transfer. Since there is a difference in the limiting value of magnetic field between widely used ICNIRP EMF guideline and IEEE C95.1 standard, there can be possible confusion when establishing EMF (Electromagnetic Field) standard on the wireless power transfer device in the future. In this paper, the induced current in the human body, which is the basic restriction of the EMF guideline, is calculated using Quasi-static FDTD method when 3D high-resolution human model is exposed to the 100kHz~10MHz magnetic field. Using this result, the feasibility of the magnetic field reference level in the ICNIRP guideline is analyzed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.93-98
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• 1999

In recent years, medical procedures have become more complex, while financial pressures for shortened hospital stays and increased efficiency in patient care have increased. As a result, several shortcomings of present film-based systems for managing medical images have become apparent. Maintaining film space is labor intensive and consumes valuable space. Because only single copies of radiological examinations exist, they are prone to being lost or misplaced, thereby consuming additional valuable time and expense. In this paper, Any-PACS for image archiving, transmission, and viewing offers a solution to these problems. Proposed Any-PACS consists of mainly four parts such as Web Module, Client-Server Module, Internal Module, Acquisition Module. In addition, Any-PACS system includes DICOM Converter that Non-DICOM file format converts standard file format. In Client-Server Module case, Proposed system is combined both SCU(Service Class Use: Client) part and SCP(Service Class provider: Server)part therefore this system provides the high resolution image processing techniques based on windows platform. Because general PACS system is too expensive for Medium and Small hospitals to install and operate the full-PACS. Also, we constructed Web Module for database connection through the WWW.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.1095-1104
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• 2000

In recent years, medical procedures have become more complex, while financial pressures for shortened hospital stays and increased efficiency in patient care have increased. As a result, several shortcomings of present film-based systems for managing medical images have become apparent. Maintaining film space is labor intensive and consumes valuable space. Because only single copies of radiological examinations exist, they are prone to being lost or misplaced, thereby consuming additional valuable time and expense. In this paper, mini-PACS for image archiving, transmission, and viewing offers a solution to these problems. Proposed mini-PACS consists of mainly four parts such as web module, client-server module, internal module, acquisition module. In addition, mini-PACS system includes DICOM converter that non-DICOM file format converts standard file format. In client-server module case, proposed system is combined both SCU (service class user: client) part and SCP(service class provider: sewer)part therefore this system provides the high resolution image processing techniques based on windows platform. Because general PACS system is too expensive for medium and small hospitals to install and operate the full-PACS. Also, we constructed web module for database connection through the WWW.

• Journal of Biomedical Engineering Research
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• v.10 no.3
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• pp.253-260
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• 1989

The time domain methods of estimating the attenuation coefficient are generally based on the analysis of statisical properties of the reflected echoes form an attenuating medium. Hence, it is often required to have a large number of data samples in order to obtain a statistically stable estimation result. In the attenuation estimation problem, this means that many different speckle patterns are required in the spatial resolution volume of an attenLlation image. In this paper, by using the fact that the speckle pattern Is sensitive to the point spread function of the ultrasound beam, we suggest a method to generate the statiscally uncorrelated or slightly correlated data samples in a given region by rotating a linear transducer and carrying out lateral scans for all rotating angles. This technique is applied to the entropy method for attenuation estimation proposed recently by the authors where the performance is verified by experiments using a tissue equivalent phantom.