• Journal of Broadcast Engineering
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• v.26 no.6
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• pp.714-724
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• 2021

The point cloud content is immersive content recorded by acquiring points and colors corresponding to the real environment and objects having three-dimensional location information. When a point cloud content consisting of three-dimensional points having position and color information is enlarged and rendered, the gap between the points widens and an empty hole occurs. In this paper, we propose a method for improving the quality of point cloud contents through inverse transformation-based interpolation using depth information for holes by finding holes that occur due to the gap between points when expanding the point cloud. The points on the back are rendered between the holes created by the gap between the points, acting as a hindrance to applying the interpolation method. To solve this, remove the points corresponding to the back side of the point cloud. Next, a depth map at the point in time when an empty hole is generated is extracted. Finally, inverse transform is performed to extract pixels from the original data. As a result of rendering content by the proposed method, the rendering quality improved by 1.2 dB in terms of average PSNR compared to the conventional method of increasing the size to fill the blank area.

• Journal of Conservation Science
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• v.38 no.3
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• pp.243-253
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• 2022

Using non-destructive analytical methods, we identified the material characteristics of two gold fabric artifacts excavated from the Cheongsong Sim clan (Bugeum Wonsam, Jikgeum Chima), including the artifact condition, fiber type, surface contamination, and metallic threads. We found that the artifacts were buried and had turned brown; thus, we were unable to determine their original color. The fiber type was determined to be silk from cocoons, based on scanning electron microscopy, Fourier transform infrared (FT-IR) analyses of Amide I, II, III, and IV peaks, and color reactions Further, the FT-IR and X-ray fluorescence (XRF) analyses identified the white and black stains as natural resin hydrolyzed substances, such as lipids and proteins, that occurred as microbial decomposition due to body decay. Finally, the XRF analyses identified the thin gold layer of the metallic yarn as gold (Au). According to the FT-IR data and the color reaction to the metallic yarn medium, the adhesive component of the medium was a product of-Amides I, II, III, and 3000 cm^-1 within Amides A and B (an animal type), respectively. Thus, the medium was identified as Hanji (Korean paper), which is made from domestically produced Broussonetia kazinoki fibers.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.2
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• pp.99-110
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• 2023

This study proposed a classification of malicious network traffic using the cyber threat framework(Mitre ATT&CK) and machine learning to solve the real-time traffic detection problems faced by current security monitoring systems. We applied a network traffic dataset called UNSW-NB15 to the Mitre ATT&CK framework to transform the label and generate the final dataset through rare class processing. After learning several boosting-based ensemble models using the generated final dataset, we demonstrated how these ensemble models classify network traffic using various performance metrics. Based on the F-1 score, we showed that XGBoost with no rare class processing is the best in the multi-class traffic environment. We recognized that machine learning ensemble models through Mitre ATT&CK label conversion and oversampling processing have differences over existing studies, but have limitations due to (1) the inability to match perfectly when converting between existing datasets and Mitre ATT&CK labels and (2) the presence of excessive sparse classes. Nevertheless, Catboost with B-SMOTE achieved the classification accuracy of 0.9526, which is expected to be able to automatically detect normal/abnormal network traffic.

• Journal of The Geomorphological Association of Korea
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• v.17 no.1
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• pp.49-57
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• 2010

To evaluate physical characteristics of open rainfall in Korea, terminal velocity of raindrop and drop size distributions (DSD) were continuously measured using by laser-optical disdrometer around Gosam reservoir, Anseong-si, Gyeonggi-do during three rainfall events from 2008 to 2009. The relationships between kinetic energies (KE, Jm^-2mm^-1; KER, Jm^-2h^-1) and rainfall intensity were obtained, respectively. Moreover, we compared the rainfall intensity from a disdrometer with the rainfall intensity from a tipping bucket raingauge to transform the kinetic energy of rainfall using the data from a tipping bucket raingauge. Therefore, the established relationships between kinetic energies (KE and KER) and rainfall intensity could be a useful model to consider the kinetic energy of raindrop using the rainfall intensity below 40mmh^-1 of max 5-min rainfall intensity in the middle of South Korea. However, to better examine the relationship between kinetic energy and rainfall intensity, further measurement will be required.

• Journal of Korean Society of Forest Science
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• v.112 no.2
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• pp.145-156
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• 2023

In this study, Fourier-transform near-infrared (FT-NIR) spectra of Korean red pine seeds stored at -18℃ and 4℃ for 18 years were analyzed. To develop seed-germination prediction models, the performance of seven machine learning methods, namely XGBoost, Boosted Tree, Bootstrap Forest, Neural Networks, Decision Tree, Support Vector Machine, PLS-DA, were compared. The predictive performance, assessed by accuracy, misclassification, and area under the curve (0.9722, 0.0278, and 0.9735 for XGBoost, and 0.9653, 0.0347, and 0.9647 for Boosted Tree), was better for the XGBoost and decision tree models when compared with other models. The 54 wave-number variables of the two models were of high relative importance in seed-germination prediction and were grouped into six spectral ranges (811~1,088 nm, 1,137~1,273 nm, 1,336~1,453 nm, 1,666~1,671 nm, 1,879~2,045 nm, and 2,058~2,409 nm) for aromatic amino acids, cellulose, lignin, starch, fatty acids, and moisture, respectively. Use of the NIR spectral data and two machine learning models developed in this study gave >96% accuracy for the prediction of pine-seed germination after long-term storage, indicating this approach could be useful for non-destructive viability testing of stored seed genetic resources.

• Journal of the Korea Society of Computer and Information
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• v.14 no.11
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• pp.97-103
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• 2009

In this thesis, we discuss the implementation of parallel processing system which is able to get a high degree of efficiency(size, cost, performance and flexibility) by using $Nios^{(R)}$ II(32bit RISC(Reduced Instruction Set Computer) processor) embedded processor in DE2-$70^{(R)}$ reference board. The designed Parallel processing system is master-slave, shared memory and MIMD(Mu1tiple Instruction-Multiple Data stream) architecture with 4-processor. For performance test of system, N-point FFT is used. The result is represented speed-up as follow; in the case of using 2-processor(core), speed-up is shown as average 1.8 times as 1-processor's. When 4-processor, the speed-up is shown as average 2.4 times as it's.

• The Mathematical Education
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• v.61 no.1
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• pp.1-28
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• 2022

The purpose of this study is to explore how students' fractional knowledge is related to their solving of proportion problems. To this end, 28 clinical interviews with four middle-grade students, each lasting about 30~50 minutes, were carried out from May 2021 to August 2021. The present study focuses on two 7th grade students who exhibited their ability to coordinate three levels of units prior to solving whole number problems. Although the students showed interiorization of three levels of units in solving whole number problems, how they coordinated three levels of units were different in solving proportion problems depending on whether the problems required reasoning with whole numbers or fractions. The students could coordinate three levels of units prior to solving the problems involving whole numbers, they coordinated three levels of units in activity for the problems involving fractions. In particular, the ways the two students employed partitioning operations and how they coordinated quantitative unit structures were different in solving proportion problems involving improper fractions. The study contributes to the field by adding empirical data corroborating the hypotheses that students' ability to transform one three levels of units structure into another one may not only be related to their interiorization of recursive partitioning operations, but it is an important foundation for their construction of splitting operations for composite units.

• Journal of Broadcast Engineering
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• v.27 no.1
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• pp.80-90
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• 2022

Currently, the domestic early warning system is issued differently for each disaster, and is operated independently by relevant organizations from central government to local governments. Representative domestic disaster warning systems include disaster broadcasting using CBS(Cell Broadcasting Service) and DMB(Digital Multimedia Broadcasting) Automatic Emergency Alert Service, DITS(Disaster Information Transform System) transmitted and displayed on TV screens, automatic response system, automated rainfall warning system, and disaster message board. However, due to the difference in the method of issuing each emergency alert at the site of an emergency disaster, the alerts are issued at different times for each media, and the delivered content is also not integrated. If these systems are integrated, it is expected that damage to people's property and lives will be minimized by sharing and integrated management of disaster information such as voice, video, and data to comprehensively judge and make decisions about disaster situations. Therefore, in this study, we present a plan for the integration of the disaster warning system along with the analysis of the operation status of the domestic early warning system.

• Journal of Service Research and Studies
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• v.11 no.2
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• pp.67-77
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• 2021

This study is a study on the methodology of establishing an innovation strategy centering on the customer experience, which is essential in order to transform the existing collection and preservation-centered mutual aid company service into a visitor-centered service. To this end, we conducted literature research on environmental changes in the funeral industry from the perspective of service science and the significance and value of customer experiences within them, good customer experiences and bad customer experiences from the perspective of customer experience management. A study was conducted to present and prove a specific model. The customer experience-oriented innovation strategy of the funeral industry means to search for various alternatives that can reach the target state from the present state, focusing on the customer, and select the most appropriate transformation plan among them. As an effect of application, it was found that it is a source of differentiation by generating positive emotions to customers, and that customer experience data is highly helpful in making important decisions for the actual resource input of the parent company. This innovation model was presented, and its value was firstly proved by analyzing the difference from the existing evaluation method. Finally, as a result of analyzing the causal relationship through regression analysis using the customer experience measurement procedure, customer experience diagnosis/evaluation, customer experience innovation strategy, and cooperative company's performance as variables, the relationship proved to be significant.

• Analytical Science and Technology
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• v.19 no.6
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• pp.460-467
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• 2006

Carbon-coated $TiO_2$ was prepared by $CCl_4$ solvent mixing method with different heat treatment temperature (HTT). Since the carbon layers derived from pitch on the $TiO_2$ particles were porous, the carbon-coated $TiO_2$ sample series showed a good adsorptivity and photo decomposition activity. The BET surface area was decreased by the increasing of the heat treatment temperature. The SEM results present to the characterization of surface texture on the carbon-coated $TiO_2$ sample and carbon distributions on the surfaces for all the materials used. The main elements of C, O and Ti were shown from EDX spectra. And the quantity of these elements is very rich in the samples. From XRD data, the pristine anatase peaks were observed in the X-ray diffraction patterns for the carbon-coated $TiO_2$ at the different HTTs. However, the rutile peaks were observed for the carbon-coated $TiO_2$ at HTT of 1073 K and 1123 K. Finally, the excellent photocatalytic activity of carbon-coated $TiO_2$ with UV-vis spectra between absorbance and time could be attributed to the homogeneous coated carbon on the external surface and structural phase transform, and the photocatalytic activity was decreased by the increasing of the HTT.