• Korean Journal of Remote Sensing
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• v.21 no.4
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• pp.287-302
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• 2005

Digital Elevation Models (DEMs) were generated by ERS-l/2 and JERS-1 SAR interferometry in Daejon area, Korea. The quality of the DEM's was evaluated by the Ground Control Points (GCPs) in city area where GCPs were determined by GPS surveys, while in the mountain area with no GCPs, a 1:25,000 digital map was used. In order to minimize errors due to the inaccurate satellite orbit information and the phase unwrapping procedure, a Differential InSAR (DInSAR) was implemented in addition to the traditional InSAR analysis for DEM generation. In addition, DEMs from GTOPO30, SRTM-3, and 1:25,000 digital map were used for assessment the resolution of the DEM generated from DInSAR. 5-6 meters of elevation errors were found in the flat area regardless of the usage and the resolution of DEM, as a result of InSAR analyzing with a pair of ERS tandem and 6 pairs of JERS-1 interferograms. In the mountain area, however, DInSAR with DEMs from SRTM-3 and the digital map was found to be very effective to reduce errors due to phase unwrapping procedure. Also errors due to low signal-to-noise ratio of radar images and atmospheric effect were attenuated in the DEMs generated from the stacking of 6 pairs of JERS-1. SAR interferometry with multiple pairs of SAR interferogram with low resolution DEM can be effectively used to enhance the resolution of DEM in terms of data processing time and cost.

• Journal of Convergence for Information Technology
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• v.11 no.12
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• pp.254-264
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• 2021

This study was conducted to investigate changes in posture and muscle characteristics by applying mat pilates and kinesio taping to college students with round shoulder posture and to investigate effective interventions. Subjects were 28 men and women with a round shoulder posture, and they were randomly assigned to a mat pilates group (MPG, n=14) and a Kinesio taping group (KTG, n=14). Each group performed the intervention for 4 weeks, and the distance from the ground to the acromion(DGA) and muscle characteristics (F: Frequency; S: Stiffness; D: Decrement) were measured before and after the intervention. Independent T-test was performed for the difference in the amount of change between groups, and the paired-sample T-test was performed for the difference between pre-post values within the group. Statistical significance level was set as 𝛼=.05. As a result of measuring the change in DGA in both groups, it was significantly decreased in MPG (p<.05). As a result of measuring the change in muscle characteristics of the two groups, the change in F in TL was significantly increased in MPG (p<.05), there was no change in TG, and the amount of change in MPG was larger in the amount of change between the two groups. appeared (p<.05). The change in S was significantly increased in MPG (p<.05). Therefore, the mat pilates conducted in this study is considered to be an effective intervention for improving the round shoulder posture and changing the muscle characteristics than kinesio taping.

• Journal of Korea Water Resources Association
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• v.54 no.12
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• pp.1265-1274
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• 2021

The analysis of hyperspectral characteristics of materials near the South Han River has been conducted using riverside area measurements by drone installed hyperspectral sensors. Each spectrum reflectance of the riverside materials were compared and analyzed which were consisted of grass, concrete, soil, etc. To verify the drone installed hyperspectral measurements, a ground spectrometer was deployed for field measurements and comparisons for the materials. The comparison results showed that the riverside materials had their unique hyperspectral band characteristics, and the field measurements were similar to the remote sensing data. For the classification of the riverside area, the K-means clustering method and SVM classification method were utilized. The supervised SVM method showed accurate classification of the riverside area than the unsupervised K-means method. Using classification and clustering methods, the inherent spectral characteristic for each material was found to classify the riverside materials of hyperspectral images from drones.

• Journal of Advanced Navigation Technology
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• v.25 no.5
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• pp.397-402
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• 2021

The real-name electric fishing gear system is one of the important policy capable to build 'abundant fishing ground' and to protect marine environment. And, fishing gear automatic-identification system is one of IoT services that can implement above-mentioned policy by using communication such as low power wide area (LPWA) and multi-sensing techniques. Fishing gear automatic -identification system can gather the location data and lost/hold data from electric buoy floated in sea and can provide them to fishermen and monitoring center in land. We have developed the communication modules and electric buoy consisted of fishing gear automatic-identification system. In this paper, we report the test results of communication distance between electric buoy and wireless node installed in fish boat and location error of electric buoy. It is confirmed that line of sight (LOS) distance between electric buoy and wireless node is obtained to be 62 km, which is two times of the desired value, and location error is obtained to be CEP 1 m, which is smaller than the desired value of CEP 5 m. Therefore, it is expected that service area and accuracy of the developed fishing gear automatic-identification system is more extended.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.403-412
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• 2021

Despite strengthening requirements for fire retardancy and applied buildings of insulation panels, the number of fires and influence of damage have increased. In this study, the thermal effects were evaluated as the separation distances, and three types of EPS panel, glass wool panel, and gypsum board panel were then selected. Temperature sensors on the panels were installed vertically from the ground. The fire source on the lamination layer of lumber was ignited by changes in the separation distances (0 cm, 25 cm, 50 cm) from the panels. The test results suggested that the maximum temperature was 349 ℃ in the EPS panel. The inside/outside shape changes were limited by the height of the low and middle positions until the critical point of a 25 cm separation distance. Furthermore, the combustion marks appeared after 500 s on average, and then the EPS panel with a high fire strength showed a broad "U type" pattern, glass wool panel, and gypsum board panel showed medium or narrow "V type" pattern. Therefore, the acquired data can provide valuable information for evaluating the fire risks and verifying fire investigation from buildings composed of these insulation panels.

• The Korean Journal of Archival Studies
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• no.7
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• pp.37-74
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• 2003

An Old document(Diploma) is a historical and unique record, so it must be collected, arranged, and preserved for research as soon as possible. Especially, for the effective use of the Old Document(Diploma), it is needed to arrange and describe the material systematically on the ground of modern archival theory. The Kyujanggak Archives in the Seoul National University has published 23 volumes of Old document(Diploma) material Old Document(Diploma). But they seem to cause the readers inconvenience, because the materials are classified and gathered only by genre, the titles or the orders of the materials are not standardized, and there is no description about the content of each Old document(Diploma). Jangseo-gak Library in The Academy of Korean Studies has also published the series of Old document(Diploma) material Old Document(Diploma) Collection. However the case is not different, since they are all mixed up with materials classified and gathered by genre, family, academy, or local school. And a great part of the materials have no titles and no description about the content of each Old document(Diploma), either. About the arrangement and description of the records, European and American archival science has established the theory of l)the principle of provenance, 2)the principle of original order, 3)levels of control, 4)collective description. These theories are valuable for the effective use of Old document(Diploma). On the viewpoint of the principle of provenance, Old document(Diploma) materials should not be classified by subject and genre, but by family and person. Then, the Old document(Diploma) materials, after collected by the unit of family or person on the viewpoint of the principle of provenance, should be arranged in their original order for more detailed arrangement and furthermore, for the work to find their relationship. This is so called the principle of original order. The hierarchical management of the Old document(Diploma) materials, for example, classifying by record group, sub-group, series, item and so on, is the concept of the levels of control, and comprehensive description of the each hierarchical structure is the concept of the collective description. Let's apply these archival theories to 34 pieces of the Chung, Man-Seok's material in the series of Old document(Diploma) material Old Document(Diploma). First, collect the Old document(Diploma) materials into Chung, Man-Seok's collection(the principle of provenance), which were scattered in the series classified by genre. Secondly, rearrange them chronologically(the principle of original order), and then we can find the comprehensive information about Chung, Man-Seok. For the hierarchical management of the Old document(Diploma) materials, we should establish a few concepts from the general, large group to specific, small item. The concepts can be organized as following; l)record group(Chung, Man-Seok record group) - 2)sub-group(personnel document, property document, family document, social activity document, political activity document, etc) - 3)series(gyoji-series, gyoseo-series, yuji-series etc. in the personnel document) - 4)folder(document with additions) - 5)item(one document). According to the the theory of the collective description, in the level of record group, there should be a collective description of Chung, Man-Seok's biography or a summary of record group. Similarly, there should be a collective description of a summary of sub-group in the level of sub-group and a summary of series in the level of series.

• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.59-66
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• 2018

The utilized coefficient of friction (UCOF) as a ratio of the shear force to the normal force on the ground during walking is used to identify the point at which slip is likely to occur. Shoe walking will change the utilized coefficient of friction by shoe design such as sole thickness and hardness, heel shape, and outsole pattern. In this study, subjects are 21 adults (10 female, 11 male, age: $25.2{\pm}2.3yrs$, height: $165.6{\pm}7.2cm$), analysis variables were walking speed, GRF, when the UCOF is maximal, and Tangent of CoP-CoM angle, and correlation analysis with the utilized friction coefficient (UCOF). As a result, First, for the shod walking the time point which UCOF is maximum about heel strike was faster and the magnitude was larger than for barefoot walking. Second, the correlation between the tangent of CoP-CoM and UCOF of right foot was higher at the left heel striking point (UCOF2_h) which occurred in the post propulsion phase than at the right heel striking point (UCOF1_h). This suggests that the right foot UCOF is related to the braking phase of left foot( which is the propulsion phase of right foot) rather than the braking phase of right foot.

• Journal of the Korean earth science society
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• v.39 no.6
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• pp.533-544
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• 2018

Rainfall is one of the most important meteorological variables in meteorology, agriculture, hydrology, natural disaster, construction, and architecture. Recently, satellite remote sensing is essential to the accurate detection, estimation, and prediction of rainfall. In this study, the accuracy of Integrated Multi-satellite Retrievals for GPM (IMERG) product, a composite rainfall information based on Global Precipitation Measurement (GPM) satellite was evaluated with ground observation data in the inland of Korea. The Automatic Weather Station (AWS)-based rainfall measurement data were used for validation. The IMERG and AWS rainfall data were collocated and compared during one year from January 1, 2016 to December 31, 2016. The coastal regions and islands were also evaluated irrespective of the well-known uncertainty of satellite-based rainfall data. Consequently, the IMERG data showed a high correlation (0.95) and low error statistics of Bias (15.08 mm/mon) and RMSE (30.32 mm/mon) in comparison to AWS observations. In coastal regions and islands, the IMERG data have a high correlation more than 0.7 as well as inland regions, and the reliability of IMERG data was verified as rainfall data.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.6
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• pp.243-250
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• 2019

Because of a moving UAV has a lot of potential/kinetic energy, if the UAV falls to the ground, it may have a lot of impact. Because this can lead to human casualities, in this paper, the population density area on the UAV flight path is defined as a dangerous area. The conventional UAV path flight was a passive form in which a UAV moved in accordance with a path preset by a user before the flight. Some UAVs include safety features such as a obstacle avoidance system during flight. Still, it is difficult to respond to changes in the real-time flight environment. Using public Big Data for UAV path flight can improve response to real-time flight environment changes by enabling detection of dangerous areas and avoidance of the areas. Therefore, in this paper, we propose a method to detect and avoid dangerous areas for UAVs by utilizing the Big Data collected in real-time. If the routh is designated according to the destination by the proposed method, the dangerous area is determined in real-time and the flight is made to the optimal bypass path. In further research, we will study ways to increase the quality satisfaction of the images acquired by flying under the avoidance flight plan.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.2
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• pp.107-113
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• 2019

In this paper, a robust filter based wind velocity estimation algorithm without an air velocity sensor in an air vehicle is presented. The wind velocity is useful information for the air vehicle to perform precise guidance and control. In general, the wind velocity can be obtained by subtracting an air velocity which is obtained by an air velocity sensor such as a pitot-tube, and a ground velocity which is obtained by a navigation equipment. However, in order to simplify the configuration of the air vehicle, the wind estimation algorithm is necessary because the wind velocity can not be directly obtained if the air velocity measurement sensor is not used. At this time, the aerodynamic coefficient of the air vehicle changes due to the turbulence, which causes the uncertainty of the system model of the filter, and the wind estimation performance deteriorates. Therefore, in this study, we propose a wind estimation method using $H{\infty}$ filter to ensure robustness against aerodynamic coefficient uncertainty, and we confirmed through simulation that the proposed method improves the performance in the uncertainty of aerodynamic coefficient.