• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.531-542
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• 2021

Open-pit mines require constant monitoring as they can cause surface changes and environmental disturbances. In open-pit mines, there is little vegetation at the mining site and can be monitored using InSAR (Interferometric Synthetic Aperture Radar) coherence imageries. In this study, activities occurring in mine were analyzed by applying the recently developed InSAR coherence-based NDAI (Normalized Difference Activity Index). The March 5 Youth Mine is a North Korean mine whose development has been expanded since 2008. NDAI analysis was performed with InSAR coherence imageries obtained using Sentinel-1 SAR images taken at 12-day intervals in the March 5 Youth Mine. First, the area where the elevation decreased by about 75.24 m and increased by about 9.85 m over the 14 years from 2000 was defined as the mining site and the tailings piles. Then, the NDAI images were used for time series analysis at various time intervals. Over the entire period (2017-2019), average mining activity was relatively active at the center of the mining area. In order to find out more detailed changes in the surface activity of the mine, the time interval was reduced and the activity was observed over a 1-year period. In 2017, we analyzed changes in mining operations before and after artificial earthquakes based on seismic data and NDAI images. After the large-scale blasting that occurred on 30 April 2017, activity was detected west of the mining area. It is estimated that the size of the mining area was enlarged by two blasts on 30 September 2017. The time-averaged NDAI images used to perform detailed time-series analysis were generated over a period of 1 year and 4 months, and then composited into RGB images. Annual analysis of activity confirmed an active region in the northeast of the mining area in 2018 and found the characteristic activity of the expansion of tailings piles in 2019. Time series analysis using NDAI was able to detect random surface changes in open-pit mines that are difficult to identify with optical images. Especially in areas where in situ data is not available, remote sensing can effectively perform mining activity analysis.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.543-557
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• 2021

Because aerosols have different spectral characteristics according to the size and composition of the particle and to the satellite sensors, a comparative analysis of aerosol products from various satellite sensors is required. In South Korea, however, a comprehensive study for the comparison of various official satellite AOD (Aerosol Optical Depth) products for a long period is not easily found. In this paper, we aimed to assess the performance of the AOD products from MODIS (Moderate Resolution Imaging Spectroradiometer), VIIRS (Visible Infrared Imaging Radiometer Suite), Himawari-8, and Sentinel-3 by referring to the AERONET (Aerosol Robotic Network) sun photometer observations for the period between January 2015 and December 2019. Seasonal and geographical characteristics of the accuracy of satellite AOD were also analyzed. The MODIS products, which were accumulated for a long time and optimized by the new MAIAC (Multiangle Implementation of Atmospheric Correction) algorithm, showed the best accuracy (CC=0.836) and were followed by the products from VIIRS and Himawari-8. On the other hand, Sentinel-3 AOD did not appear to have a good quality because it was recently launched and not sufficiently optimized yet, according to ESA (European Space Agency). The AOD of MODIS, VIIRS, and Himawari-8 did not show a significant difference in accuracy according to season and to urban vs. non-urban regions, but the mixed pixel problem was partly found in a few coastal regions. Because AOD is an essential component for atmospheric correction, the result of this study can be a reference to the future work for the atmospheric correction for the Korean CAS (Compact Advanced Satellite) series.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.2
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• pp.81-88
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• 2021

In this paper, by applying LTCC substrate, the library of the passive elements is implemented. And it can be used in 24 GHz circuits. Depending on how to use it to the circuit, it is required large value by designing the basic structures such as electrode capacitor and spiral inductor. However they are not available in high-frequency domain, because their SRF(Self-Resonant Frequency) is lower than the frequency of 24-GHz. By solving the limit, this paper devised passive elements classified for the DC and the high-frequency domain. The basic structure is suitable for low frequency under 1~2 GHz like DC. The microstrip λ/8 length stub structure is proposed to use for high-frequency like 24-GHz. The open and short stub structure operate as a capacitor and inductor respectively, also they have their impedances. Through their impedances, we can extract the value with the impedance-related equation. In this paper, the proposed passive elements are produced with the permittivity 7.5 LTCC substrate, the basic structure which are available in the DC constituted a library of capacitance of 2.35 to 30.44 pF and inductance of 0.75 to 5.45 nH, measured respectively. The stub structure available in the high-frequency domain were built libraries of capacitance of 0.44 to 2.89 pF and inductance of 0.71 to 1.56 nH, calculated respectively. The measurements have proven how to diversify value, so libraries can be built more variously. It will be an alternative to the passive elements that it is possible to integrate with the operation circuit of radar module for the frequency 24-GHz.

• Journal of the Society of Disaster Information
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• v.17 no.1
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• pp.10-24
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• 2021

Purpose: The purpose of this study is to determine the dangers of biodiesel and general diesel mixtures currently used as alternative fuels by equipment (tag method and penski Marten method) and to determine the difference between flash point and combustion point (closed, open) according to test methods. It is intended to be used as a reference material for identification and evaluation of firecausing substances by confirming the risk of mixtures by comparative analysis and measurement, and establishing a risk assessment method for chemical substances. Method: Flash point test method and result treatment were tested based on ASTM and KS M mode, which are tag sealing and pen schematense test methods used as flash point and combustion point test methods for crude oil and petroleum products. The manufacturer of the equipment used in this experiment was a test equipment that satisfies the test standards of KS M 2010 with equipment produced by TANAKA of Japan. The flash point and combustion point were measured, and the flash point according to the test method of biodiesel and general diesel mixture ( Closed, open), and the ignition point of a mixture of biodiesel and general diesel was compared and analyzed for ignition risk compared with conventional diesel. Results: Looking at the experimental results, first, as an analysis of the risk of flammability of the mixture, the flash point of a substance containing 70% biodiesel was found to be about 92℃ based on general diesel with a flash point of 64.5℃, and gasoline and biodiesel or When the biodiesel mixture was synthesized, it was confirmed that the flash point tends to decrease. In addition, the difference between the flash point and the combustion point was analyzed as about 20 ~ 30℃, and when a small amount of gasoline or methanol was mixed, the flash point was lowered, but it was confirmed that the combustion point was similar to that of the existing mixture. Conclusion: In this study, in order to secure the effectiveness of the details of the criteria for judging dangerous materials in the existing Dangerous Materials Safety Management Act, and to secure the reliability and reproducibility of the judgment of dangerous materials, we confirm the criteria for judging the risk of the mixture through an experimental study on flammable mixtures. It will be able to provide reference data for experimental criteria for flammable liquids that are regulated in the field. In addition, if this study accumulates know-how on experiment by test method, it is expected that it can be used as a basis for research on risk assessment and research on dangerous goods.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.483-493
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• 2011

Erosion control dams play a primary role in preventing or controlling natural disasters (landslide and debris flow etc.) and also conserve ecosystem in forested watersheds. This study examines structural characteristics of the dams such as the height of ecosystem control and the ecosystem permeability of the erosion control dams under standard drawings and the existing construction works. The objective of this study was to characterize the type classification of erosion control dams as ecosystem. Average permeability was highest on eco-piller dam (63.0%), followed in increasing order by wire rope (13.9%), silt dam (10.9%), multifunctional dam (7.2%), and gravity dam (0.4%). The height of ecosystem control was highest on gravity dam (3.2 m), followed in increasing order by multifunctional dam (1.7 m), wire rope dam (1.2 m), silt dam (0.6 m), and eco-piller dam (0.0 m). Criteria for defining the height of ecosystem control was indefinite. We grouped erosion control dams into three functional types (eco-connection, eco-semi connection, and eco-disconnection) by considering physical and structural characteristics such as the ecosystem permeability and the height of ecosystem control. The type of eco-connection (permeability > 20%) had connection areas from streambed to adjacent riparian areas, and these connection areas serve as ecosystem corridors for fauna and flora. Typical wildlife species includes mammals, reptiles, amphibians, and fishes. The type of eco-semi connection (5% < permeability < 20%) had < 2 m in the eco-barrier height from streambed, however, this type of dams partially serve as wildlife corridors and often provide fish ways. The type of eco-disconnection (permeability < 5%) had > 2 m in the eco-barrier height from streambed, thereby preventing wildlife movement.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.29 no.3
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• pp.134-146
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• 2011

Gyeokgu is a group ball game transmitted into the Joseon Dynasty period as acquiring a great vogue among the royal palace and people in Goryeo Dynasty after being introduced into the country from China. This research aimed through historical investigation to look into the form in which the Goryeo dynasty's kings enjoyed Gyeokgu game, and the historical-spatial signification and the locational characteristics of Gujeong(the ground where play Gyeokgu) which is the courtyard where Gyeokgu game was held centering around the Goryeo dynasty's palace where Gyeokgu was prosperous most. We researched and analyzed the data for research after extracting the records related to Gyeokgu from three historical data of the true records of the Goryeo Dynasty. Upon investigation, twelve among 34 kings of the past generations were concerned with Gyeokgu in Gyeokgu game participation form, and 46 times were recorded in historical records in total. In the participation form, kings participated personally in 9 times among 46 Gyeokgu games, and viewed games in case of 37 times. Among these kings, the 18th generation king Uijong was recorded most as 17 times(36.9%) in Gyeokgu records. Places where Gyeokgu were held were 25 places in total including royal palace, detached palace, Lu-jeong, Buddhist temple, private residences, markets and streets, other outside of the royal court and so on, and 46 time-Gyeokgu games in total were held in these places. 21 time(45.6%)-Gyeokgu games were held in only 5 detached place among these places. So, detached palace were used most for Gyeokgu games. In particular, Gyeokgu games were held most in Suchanggung palace and Jangwonjeong palace among these detached palaces, and all these things were recorded during the reign of King Uijong. Gyeokgu game which was prevalent by the end of the Goryeo Dynasty showed a progression to a national festival which kings, personally coming into streets or Jeoja(an archaic word for "market"), enjoyed with the crowd.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.246-255
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• 2011

This study was carried out to investigate the characteristics of wind damaged trees in the Hongneung Arboretumin Korea. Many trees in the Hongneung Arboretum were damaged by the 'Kompasu', the seventh typhoon in the year of 2010 having strong impacts on the central region of Korea. Damaged trees were divided into 3 damage types: windthrow, slanted and broken trees. Most of damaged trees (97.3%) were found at low slope (below 15 degree) or medium slope (15~20 degree). The 45.3% of damaged trees were coniferous and 54.7% were deciduous trees. The wind speed was recorded for the duration of the typhoon from 04:00 AM to 12:00 PM on September 2. The average wind speed and the maximum instantaneous wind speed inside the forest were 1.4 m/sec and 3.5 m/sec, respectively. The highest peak of the average and the maximum instantaneous wind speed inside of forest, 3.4 m/sec and 8.7 m/sec respectively, were recorded at 06:10 AM on September 2. To analyze relationship between wind characteristics and the damage types, the average wind speed and the frequency of wind wave was compared to those of pre-typhoon period (Feb. 13, Feb. 20, Apr. 21, Oct. 16, 2009 and Mar. 20, 2010). The results indicated that the damaged trees were affected by frequent wind wave rather than the wind speed itself. Also average wind direction inside the forest was analyzed to investigate the impact of wind direction on the damaged trees. The wind had mainly blown from SE and SW, and the maximum instantaneous wind direction was SE direction overall. Most of the damaged trees (84.0%) had fallen down to the NW or NE direction. This result showed that the fallen direction of the damaged trees and wind direction was highly related. Therefore, we found that the frequency of wind wave was the main factor of wind damages during the typhoon 'Kompasu' and wind direction was highly related to the fallen direction.

• Journal of Korean Classical Literature and Education
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• no.39
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• pp.67-97
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• 2018

The purpose of this paper is to clarify that the difference between past and present response to the same folktales relates to other cultural contexts. This is part of the research to explore the methodology of folktale education for intergenerational communication. This paper compares the reaction on a storytelling site from the past to with current college students' impressions. On the older site, the storyteller and audience sympathized with the characters of . Additionally, they were pleased with the conclusion that the characters would get a new family. However, university students thought that the characters of was incompetent. University students evaluated their success as depending on other people, accidentally obtained. Such a difference was closely related to the culture of the group intervening when understanding the folktale. In the past culture, empathy, interdependence, and unity were considered important values. Meanwhile, the new-generation culture emphasized the individual's free will and rights, diligence, and honesty. As a result, due to differences in cultural context, university students distorted , and communication with past generations was also broken. In this paper, we study the folktale education methodology that helps communication between generations. this paper proposes that It is more suitable to tile the story instead of for university students. That is because resembles the cultural context of university students. At the same time, it has the same problem as .

• Journal of Korean Classical Literature and Education
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• no.39
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• pp.221-246
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• 2018

In this text, the author examines the aspects and characteristics of the three forms that were created and enjoyed when the upper-class nobles of Japan "combined(混淆)" waka(和歌) and Chinese poetry(漢詩) between the 10th and 17th centuries. The three forms are the "Collection of Japanese and Chinese poems for singing"(和漢朗詠), "A collection of Japanese and Chinese poems" (詩歌合), and the "Renku renga"(聯句連歌). "Collection of Japanese and Chinese poems for singing" appeared in the 10th century, "A collection of Japanese and Chinese poems" appeared in the 12th century, "Renku renga" appeared in the 14th century, and all three continued to influence the history of Japanese literature after that time. As the combination of literary Japanese and Chinese progressed, the gap between waka and Chinese poetry decreased until they finally combined to create a single work. That is, waka and Chinese poetry converged in one place in multiple ways: as a work that was appropriate to be recited("Collection of Japanese and Chinese poems for singing"), facing each other work against work in a competition("A collection of Japanese and Chinese poems"), and, in the end, they reached the point where they were interchangeable as lines making up long poems(長詩)("Renku renga"). The combination of literary Japanese and Chinese can be said to be the Japanese version of the common movement in East Asian literary history during the Middle Ages to make songs from one's own language flawless in Chinese poetry. Meanwhile, by examining the status changes that appeared as Chinese poetry paralleled, fought with, replaced, and combined with waka, we can find clues to explain the attitudes of the Japanese people on Chinese poetry during the period when the three forms existed, as well as the characteristics of Japanese Chinese poetry that appeared in response to that. The preferences not of "myself" but of the "audience," content and expressions that revere the period rather than the inner self of the poet, and the fact that it is a means for enjoyable pleasure rather than having the original characteristics of lyrical poetry for self-expression are all characteristics of Chinese poetry in Japan during the early and late Middle Ages period. These characteristics can be said to be the current that flows in the underbelly of the history of Chinese literature in Japan. This author believes that the key to discussing the history of Chinese literature in Japan during the Middle Ages period from the perspective of East Asian literary history can be found here.

• 기호학연구
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• no.54
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• pp.93-117
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• 2018

The process of creating Hunminjeongeum described in Haerye version of Hunminjeongeum shows a rule of signification by which a signifiant represents a referent. In this article, I will suggest two types, the mythical and the anti-mythical, that affect the iconic relation between signifiant and referent, and consider how they are realized in Hunminjeongeum. The mythical type is shown as Yin-Yang and the Five Elements Theory and Three Elements Theory of Heaven, Earth and Man dominating the thought of intellectuals at that time. It had became mythos, that is the object of absolute belief, by connecting with the power of King at that time. It is very metaphysical and involves a kind of grand narrative. It is also the voice from the past in time and from China in space. It is reflected in Hunminjeongeum's letter system intactly. Meanwhile, the anti-mythical type also affects the creation of Icon in Hunminjeongeum. Even if Hunminjeongeum had been created from King Sejong's project, its intention seemed to be educational and practical. That is the problem of that time, not of past time, and for common class, not for ruling class. It can be considered as logos in that it had been planned and processed at a real-life situation at that time. Some arguments between King Sejong and liege Choi, Manri about the validity of Hunminjeongeum also show that the creation of Hunminjeongeum had involved the problem of critical logos. Above all, in that referents of Icons of Hunminjeongeum are the figures of human vocal organs, we can suggest that these Icons also implied an Indexicality implying actual connection between voice and body. It can be considered as a deconstrucion of metaphysics and grand narrative that had been dominated by foresaid mythical type. Hereafter, from time when Hunminjeongeum have been widely used, mythos of metaphysics and grand narrative that had dominated Hunminjeongeum have been deconstructed and Hunminjeongeum has become to realize its potential competence of pragmatic sign system for the convenience of common people. Therefore, I expect that the cultural potentiality of Hangul today can be realized by such tendency of logos incessantly deconstructing mythos, that is one direction of mythosemiosis.