• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.43.2-43.2
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• 2014

We investigate the ionized gas kinematics at the center of 6 nearby Seyfert galaxies, using the integral field spectroscopy data from the Calar Alto Legacy Integral Field spectroscopy Area survey Data Release 1. To understand the kinematic nature of the ionized gas in the narrow-line regions (NLRs), we measured the flux, velocity, and velocity dispersion of the [OIII] $5007{\AA}$ and Ha $6563{\AA}$ emission lines, after subtracting a best-fit stellar population model representing the stellar features. At the same time, we measured stellar velocity as a reference for the systemic velocity, and stellar velocity dispersion. We spatially resolved the velocity structure of the ionized gas using each emission line and compared it to that of stars. In this poster we present the flux, velocity, and velocity dispersion maps of the ionized gas and stars, and discuss the nature of the ionized gas outflows in the central kiloparsec scale.

• Economic and Environmental Geology
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• v.24 no.3
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• pp.309-318
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• 1991

Analysis for landslides was studied in framework of Chungju dam right abutment, 6.5km northeast of Chungju city. $5.5{\times}10^6m^3$ landslide materials were excavated during dam construction for safety of the Chungju dam. Geology of study area is composed mainly of meta sediments such as dolomitic limestone, quartzite and schist which are dipping toward the Nam Han river. Scanline survey of discontinuities was performed for slope stability, resistivity exploration was performed for the evaluation of potential failure plane, and direct shear strength test of rocks and soils was performed for the effect on landslide. Monitoring systems of tiltmeter, tensiometer, ground water observation hole and level monument were installed during dam construction and interpreted for the evaluation of slope instability. Kinematic solution of the geological structure and evaluation using safety factor for slope may prove the failure of the slope.

• Electronics and Telecommunications Trends
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• v.38 no.3
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• pp.11-19
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• 2023

Drones, which were early operated by remote control, have evolved to enable autonomous flight by combining various sensors and software tools. In particular, autonomous flight of drones was possible since the application of GNSS-RTK (global navigation satellite system with real-time kinematic positioning), a precision satellite navigation technology. For instance, unmanned drone delivery based on GNSS-RTK data was demonstrated for pizza delivery in Korea for the first time in 2021. However, the vulnerabilities of GNSS-RTK should be overcome for delivery drones to be commercialized. In particular, jamming in the navigation system and low positioning accuracy in urban areas should be addressed. Solving these two problems can lead to stable flight, takeoff, and landing of drones in urban areas, and the corresponding solutions are expected to establish a hybrid positioning technology. We discuss current trends in hybrid positioning technology that can either replace or complement GNSS-RTK for stable drone autonomous flight.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.50.1-50.1
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• 2019

Ultra Metal-Poor (UMP; [Fe/H] < -4.0) stars are thought to be true second generation of stars. Thus, the chemistry and kinematics of these stars serve as powerful tools to understand the early evolution of the Milky Way (MW). However, only about 40 of these stars have been discovered thus far. To increase the number of these stars, we selected UMP candidates from low-resolution spectra (R ~ 2000) of the Sloan Digital Sky Survey (SDSS) and Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST), and performed high-resolution (R ~ 40,000) spectroscopic follow-ups with Gemini/GARACES. In this study, we present chemical and kinematic properties of the observed UMP candidates, and infer the nature of their progenitors to trace the chemical enrichment history of the MW.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.58.2-58.2
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• 2020

We present a method for determining the abundance ratio of nitrogen to iron ([N/Fe]) from low-resolution (R~2000) stellar spectra from large spectroscopic surveys such as Sloan Digital Sky Survey (SDSS) and Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). The basic idea of the method is to match a grid of synthetic spectra with an observed spectrum in the CN band region around 3883 Å. To calibrate our estimate of [N/Fe], we make use of the giants observed in Apache Point Observatory Galaxy Evolution Experiment (APOGEE), which are also observed in the SDSS. This method will be applied to the Galactic halo stars to determine [N/Fe], and the measured nitrogen abundance ratios will be used to investigate the C-N anti-correlation, which is observed in globular clusters, to trace their origin with their kinematic properties.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.1
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• pp.87-96
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• 2012

The U.S. Geological Survey (USGS) announced that an earthquake of 9.0 magnitude had occurred near the east coast of Japan on March 11, 2011, resulting in a displacement of the crust of about 2.4 meters. The Korean peninsula is located on the Eurasian tectonic plate that stretches out to Japan; therefore, there is a high possibility of being affected by an earthquake. The Korean GPS CORS network operated by the National Geographic Information Institute (NGII) was processed for ten days before and after the earthquake. Both static and kinematic baseline processing were tested for the determination of crustal deformation. The static baseline processing was performed in two scenarios: 1) fixing three IGS stations in China, Mongolia and Russia; 2) fixing SUWN, one of the CORS networks in Korea, in order to effectively verify crustal deformation. All data processing was carried out using Bernese V5.0. The test results show that most of the parts of the Korean peninsula have moved to the east, ranging 1.2 to 5.6 cm, compared to the final solution of the day before the earthquake. The stations, such as DOKD and ULLE that are established on the islands closer to the epicenter, have clearly moved the largest amounts. Furthermore, the station CHJU, located on the southwestern part of Korea, presents relatively small changes. The relative positioning between CORS confirms the fact that there were internal distortions of the Korean peninsula to some extent. In addition, the 30-second interval kinematic processing of CORS data gives an indication of earthquake signals with some delays depending on the distance from the epicenter.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.42.1-42.1
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• 2017

We present the results from an extensive spectroscopic survey of the central region of the nearby galaxy cluster Abell 2199 (A2199) at z=0.03. By combining 775 new redshifts from the MMT/Hectospec observations with the data in the literature, we construct a large sample of 1624 galaxies with measured redshifts at R<30', which redsults in high spectroscopic completeness at $r_{petro,0}$<20.5 (77%). We use these data to study the kinematics and clustering of galaxies, focusing on the comparison with those of the intracluster medium (ICM) from Suzaku X-ray observations. We identify 406 member galaxies of A2199 at R<30' using the caustic technique. The velocity dispersion profile of cluster members appears smoothly connected to the stellar velocity dispersion profile of the cD galaxy. The luminosity function is well fitted with a Schechter function at $M_r$<-15. The radial velocities of cluster galaxies generally agree well with those of the ICM, but there are some regions where the velocity difference between the two is about a few hundred kilometers per second. The cluster galaxies show a hint of global rotation at R<5' with $v_{rot}=300-600kms^{-1}$, but the ICM in the same region does not show such rotation. We apply a friends-of-friends algorithm to the cluster galaxy sample at R<60' and identify 32 group candidates, and examine the spatial correlation between the galaxy groups and X-ray emission. This extensive survey in the central region of A2199 provides an important basis for future studies of interplay among the galaxies, the ICM, and the dark matter in the cluster.

• Journal of People, Plants, and Environment
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• v.24 no.4
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• pp.441-450
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• 2021

Background and objective: The purpose of study is to analyze the three-dimensional (3D) structure by creating a 3D model for green spaces in a park using unmanned aerial vehicle (UAV) images. Methods: After producing a digital surface model (DSM) and a digital terrain model (DTM) using UAV images taken in Mureung Park in Chuncheon-si, we generated a digital tree height model (DHM). In addition, we used the mean shift algorithm to test the classification accuracy, and obtain accurate tree height and volume measures through field survey. Results: Most of the tree species planted in Mureung Park were Pinus koraiensis, followed by Pinus densiflora, and Zelkova serrata, and most of the shrubs planted were Rhododendron yedoense, followed by Buxus microphylla, and Spiraea prunifolia. The average height of trees measured at the site was 7.8 m, and the average height estimated by the model was 7.5 m, showing a difference of about 0.3 m. As a result of the t-test, there was no significant difference between height values of the field survey data and the model. The estimated green coverage and volume of the study site using the UAV were 5,019 m² and 14,897 m³, respectively, and the green coverage and volume measured through the field survey were 6,339 m² and 17,167 m³. It was analyzed that the green coverage showed a difference of about 21% and the volume showed a difference of about 13%. Conclusion: The UAV equipped with RTK (Real-Time Kinematic) and GNSS (Global Navigation Satellite System) modules used in this study could collect information on tree height, green coverage, and volume with relatively high accuracy within a short period of time. This could serve as an alternative to overcome the limitations of time and cost in previous field surveys using remote sensing techniques.

• Geophysics and Geophysical Exploration
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• v.8 no.1
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• pp.59-66
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• 2005

The main purpose of this paper is to describe a highly efficient common mid-point (CMP) data acquisition method for ground-penetrating radar (GPR) surveying, which is intended to widen the application of GPR. The most important innovation to increase the efficiency of CMP data acquisition is continuous monitoring of the GPR antenna positions, using a real-time kinematic Global Positioning System (RTK-GPS). Survey time efficiency is improved because the automatic antenna locating system that we propose frees us from the most time-consuming process-deployment of the antenna at specified positions. Numerical experiments predicted that the data density and the CMP fold would be increased by the increased efficiency of data acquisition, which results in improved signal-to-noise ratios in the resulting data. A field experiment confirmed this hypothesis. The proposed method makes GPR surveys using CMP method more practical and popular. Furthermore, the method has the potential to supply detailed groundwater information. This is because we can convert the spatially dense dielectric constant distribution, obtained by using the CMP method we describe, into a dense physical value distribution that is closely related to such groundwater properties as water saturation.

• The Journal of Korean Academy of Prosthodontics
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• v.28 no.2
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• pp.125-146
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• 1990

The relationale for recording mandibular movement is to accurately adjust an articulator. Techniques to record mandibular movement include radiographic interpretation, extraoral tracing, and intraoral recording materials. This study was performed to compare the concylar guidance inclination and Bennett shift(immediate & progressive side shift)obtained by using an electronic pantograph, pantograph and wax interocclusal records in Korean. Ten adults who have normal occlusion and are free of TMJ dysfunction were selected and clutches were constructed. At first Pantronic survey was performed three times by using an kinematic hinge axis according to manufacturer's direction. Next pantographic survey was performed three times and the articulator was adjusted with each pantographic recording. And then maxillary cast was attached to the articulator with pantographic as a face-bow and the mandibular cast was mounted to the articulator with centric relation record. Three protrusive, three left lateral and three right lateral wax interocclusal records were taken on the subjects and the articulator was adjusted with each interocclusal record. Protrusive condylar inclination, lateral condylar inclination, immediate side shift and progressive side shift obtained by using electronic pantograph, pantograph and wax interocclusal record were compared and analized. The results were as follows; 1. The average left and right protrusive and orbiting condylar inclination($33.7^{\circ},\;37.1^{\circ},\;40.6^{\circ},\;43.5^{\circ}$) record with Pantronic was significantly greater than that recorded with other methods. 2. The average left and right protrusive and orbiting condylar inclination($24.8^{\circ},\;27.0^{\circ},\;31.4^{\circ},\;32.4^{\circ}$)recorded with wax interocclusal record was less than that of other methods. 3. The average left and right immediate side shift(0.57mm,0.44mm)recorded with wax interocclusal record was greater than that of other methods and the average left rigtht immmediate side shift(0.30mm,0.41mm)recorded with Pantronic was significantly greater than that recorded with pantograph(0.11mm,0.20mm). 4. The average variance of wax interocclusal was signivicantly higher than that of other methods.