• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.7 no.2
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• pp.35-43
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• 1989

The improvements of highly accurate and dense control networks are major requirements to carry out numerical surveying and a large scale mapping for cadastral renovation. In the most conventional photogrammetric solutions, adjusted control coordinates have been applied to block triangulations. However, this study, imploying real data and those of simulated as well, contributes to a simultaneously combined adjustment. It also contains such photogrammetric as photocoordinates and geodetic observations like distances, angles and hight differences. Its purpose is to introduce the improved results, despite it is not sufficient for the ground network. In addition, through the detection of gross error, more precise observational data can be selected for the better adjustment. All in all, the result of this study can be summarized as follows : First, even if the ground control points are not sufficient nor existed at all, the combination of pbotogrammetric and geodetic observations are improved its accuracy. Secondly, the case #2 is more accurate than that of #3, and the case #7 comes into close to that of #6.

• Journal of the Korean earth science society
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• v.40 no.4
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• pp.406-413
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• 2019

Red-Green-Blue (RGB) imagery techniques are useful for both forecasters and public users because they are intuitively understood, have advantageous visualization, and do not lose observational information. This study presents a novel RGB convective cloud product and its application to tropical cyclone analysis using Communication, Oceanography, and Meteorology (COMS) satellite observations. The RGB convective cloud product was developed using the brightness temperature differences between WV ($6.75{\mu}m$) and IR1 ($10.8{\mu}m$), and IR2 ($12.0{\mu}m$) and IR1 ($10.8{\mu}m$) as well as the brightness temperature in the IR1 bands of the COMS, with the threshold values estimated from the Korea Meteorological Administration (KMA) radar observations and the EUMETSAT RGB recipe. To verify the accuracy of the convective cloud RGB product, the product was applied to the center positions analysis of two typhoons in 2013. Thus, the convective cloud RGB product threshold values were estimated for WV-IR1 (-20 K to 15 K), IR1 (210 K to 300 K), and IR1-IR2 (-4 K to 2 K). The product application in typhoon analysis shows relatively low bias and root mean square errors (RMSE)s of 23 and 28 km for DANAS in 2013, and 17 and 22 km for FRANCISCO in 2013, as compared to the best tracks data from the Regional Specialized Meteorological Center (RSMC) in Tokyo. Consequently, our proposed RGB convective cloud product has the advantages of high accuracy and excellent visualization for a variety of meteorological applications.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2D
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• pp.191-198
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• 2010

The displacement of slope is a key factor in predicting the risk of a landslide. Therefore, the slope displacement should be continuously observed with high accuracy. Recently, high-tech equipment such as optical fiber sensor, GPS, total station and measuring instrument have been used. However, such equipment is poorly used in fields due to economics, environment, convenience and management. Because of this, development of substantial observational techniques for varied slope observation and field applications is needed. This study analyzed the possibility of terrestrial LiDAR for slope monitoring and suggested it as information-obtaining technique for slope investigation and management. For that, this study evaluated the monitoring accuracy of terrestrial LiDAR and performed GRID analysis to read the displacement area with the naked eye. In addition, it suggested a methodology for slope monitoring.

• Korean Journal of Remote Sensing
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• v.40 no.3
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• pp.269-274
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• 2024

High-quality precipitation data are crucial for various industries, including disaster prevention. In South Korea, long-term high-quality data are collected through numerous ground observation stations. However, data between these stations are reprocessed into a grid format using interpolation methods, which may not perfectly match actual precipitation. A prime example of real-time observational grid data globally is the Integrated Multi-satellite Retrievals for Global Precipitation Measurement (GPM IMERG) from National Aeronautics and Space Administration (NASA), while in South Korea, ground radar data are more commonly used. GPM and ground radar data exhibit distinct differences due to their respective processing methods. This study aims to analyze the characteristics of GPM and Constant Altitude Plan Position Indicator(CAPPI),representative real-time grid data, by comparing them with ground-observed precipitation data. The study period spans from 2021 to 2022, focusing on hourly data from Automated Synoptic Observing System (ASOS) sites in South Korea. The GPM data tend to underestimate precipitation compared to ASOS data, while CAPPI shows errors in estimating low precipitation amounts. Through this comparative analysis, the study anticipates identifying key considerations for utilizing these data in various applied fields, such as recalculating design rainfall, thereby aiding researchers in improving prediction accuracy by using appropriate data.

• The Korean Journal of Emergency Medical Services
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• v.24 no.1
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• pp.67-76
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• 2020

Purpose: Effective time management, as well as life-saving care, are important in maximizing the prognosis of patients who have sustained major traumas. This study evaluated the appropriateness of emergency medical system (EMS) provider's essential care and how this care impacted on-scene time in patients with major traumas. Methods: This retrospective observational study analyzed the EMS major trauma documents, classified according to the physiological criteria (Glasgow coma scale <14, systolic blood pressure <90mmHg, Respiration rate <10 or >29) in Daejeon, from January, 2015 to December, 2018. Results: Of the 707 major trauma cases, the mean on-scene time was 7.75±4.64 minutes. According to EMS guidelines, essential care accuracy was 67.5% for basic airway, 36.4% for advanced airway, 91.2% for cervical collar, 81.5% for supplemental oxygen, 47.0% for positive pressure ventilation, 19.9% for intravenous access and fluid administration, and 96.0% for external hemorrhage control. Factors affecting on-scene time were positive pressure ventilation (p<.004), and intravenous access and fluid administration (p<.002). Conclusion: Adherence to guidelines was low during advanced airway procedures, positive pressure ventilation, intravenous access, and fluid administration. In addition, the on-scene time was prolonged when the practitioner provided positive pressure ventilation, intravenous access, and fluid administration; however, these durations did not exceed the recommended 10 minutes.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.85.2-85.2
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• 2012

In this paper, we introduce the 3D modeling of the coronal magnetic field in the solar active region by extrapolating from the 2D observational data numerically. First, we introduce a nonlinear force-free field (NLFFF) extrapolation code based on the MHD-like relaxation method implementing the cleaning a numerical error for Div B proposed by Dedner et al. 2002 and the multi-grid method. We are able to reconstruct the ideal force-free field, which was introduced by Low & Lou (1990), in high accuracy and achieve the faster speed in the high-resolution calculation (512^3 grids). Next we applied our NLFFF extrapolation to the solar active region NOAA 10930. First of all, we compare the 3D NLFFF with the flare ribbons of Ca II images observed by the Solar Optical Telescope (SOT) aboard on the Hinode. As a result, it was found that the location of the two foot-points of the magnetic field lines well correspond to the flare ribbon. The result indicates that the NLFFF well capture the 3D structure of magnetic field in the flaring region. We further report the stability of the magnetic field by estimating the twist value of the field line and finally suggest the flare onset mechanism.

• Journal of The Korean Astronomical Society
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• v.47 no.6
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• pp.201-207
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• 2014

We report the development of solar flux receivers operating at 2.8 GHz to monitor solar radio activity. Radio waves from the sun are amplified, filtered, and then transmitted to a power meter sensor without frequency down-conversion. To measure solar flux, a calibration scheme is designed with a noise source, an ambient load, and a hot load at $100^{\circ}C$. The receiver is attached to a 1.8 m parabolic antenna in Icheon, owned by National Radio Research Agency, and observation is being conducted during day time on a daily basis. We compare the solar fluxes measured for last seven months with solar fluxes obtained by DRAO in Penticton, Canada, and by the Hiraiso solar observatory in Japan, and finally establish equations to convert observed flux to the so-called Penticton flux with an accuracy better than 3.2 sfu.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.68.2-68.2
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• 2018

Spectroscopic observations commonly use a slit or fiber; however, non-slit spectroscopy enables us to observe a larger number of targets in one frame of image. Hence, it has been adopted as an observational mode for observatories like HST and JWST. Slitless spectroscopy requires wavelength calibration solutions in order to distinguish and measure the absorption / emission lines from the spectra with high accuracy. We installed the Volume Phase Holographic (VPH) grating to SQUEAN camera on the McDonald 2.1m telescope and obtained images with spectral resolutions of ~ 100 and 200. In order to derive the wavelength calibration, we measured the distances between the 0th order images and spectral features of various quasars. The distances are converted to wavelengths using the known wavelengths of the emission lines. We tested several different methods of spectral extraction and peak estimation of emission lines. We will present the results for the wavelength calibration and suggest the reliable methods to find the solution.

• Journal of Navigation and Port Research
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• v.33 no.2
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• pp.99-104
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• 2009

The Kinematic GPS is well known to provide a quite good accuracy of positioning within an level. Although kinematic GPS assures high precision measurement on the basis of an appreciable distance between a reference station and an observational point, it has measurable distance restriction within 20 km from a reference station on land. Therefore, it is necessary to make out a simple and low-cost method to obtain accurate positioning information without distance restriction In this paper, the velocity integration method to get the precise velocity information of a ship is explained. The experimental results of Zig-zag maneuver and Williamson turn as the ship's maneuvering test, and other experimental results of ship's movement during leaving and entering the port with low speed were shown. From the experimental results, ship's course, speed and position are compared with those obtained by kinematic-GPS, velocity integration method and dead reckoning position using Gyro-compass and Doppler-log.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.10a
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• pp.49-55
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• 2006

Kinematic GPS provides quite good accuracy of position in cm level. Though K-GPS assures high precision measurement in cm level on the basis of an appreciable distance between a station and an observational point, but it has measurable distance restriction within 20 km from a reference station on land. So it is necessary to make out a simple and low-cost method to obtain accurate positioning information without distance restriction. In this paper, the velocity integration method to get the precise velocity information of ship is explained. Next two experimental results (Zig-zag maneuvering test and Williamson turn) as the ship's maneuvering test and also the experimental results of leaving and entering port as slow speed ship's movement were shown. In these experimental results, ship's course, speed and position are compared with those obtained by kinematic-GPS, velocity integration method and dead reckoning position using Gyro-compass and Doppler-log.