• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.2
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• pp.5-13
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• 2019

Orostachys species grow from anywhere in Korea. This variety, which lives in the harsh areas of the beach and mountains, is known to have as much change as it was isolated. It has been used as a medicine for a long time, and now the flower is beautiful and has been developed for horticulture. As a result of morphological characteristics and component analysis of three Orostachys species, the following results were obtained. 1. Orostachys species showed two types of leaves according to the growing environment. O. japonica (Maxim.) A. Berger and O. minuta (Kom.) A. Berger were lanceolate, and O. chongsunensis Y. N. Lee was obovate. 2. The leaves were all green. However, some of the O. japonica (Maxim.) A. Berger had white powder. Some of the O. minuta (Kom.) A. Berger was green with red spots on the back. O. chongsunensis Y. N. Lee showed strong gray before flowering but weak green when flowering. 3. The thorns of the leaves were O. japonica (Maxim.) A. Berger and O. minuta (Kom.), but O. chongsunensis Y. N. Lee was not. 4. Whether it was a leaf dot or not, there were dots in O. japonica (Maxim.) A. Berger and there were dots on the O. minuta (Kom.) and the O. chongsunensis Y. N. Lee. 5. The flowers were all white, and the stamens were red in O. japonica (Maxim.) A. Berger and O. minuta (Kom.) A. Berger and white in O. chongsunensis Y. N. Lee. 6. It was confirmed that the ingredients in Orostachys species contained kaempferol, quercetin, flavonoid etc., which have high antioxidant activity.

• Journal of Practical Engineering Education
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• v.15 no.1
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• pp.73-80
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• 2023

The advancement of online technology in the 21st century has increased online courses and web-based communication in higher education. This type of education is not limited by time or location and has made it possible to expand university campuses globally and broaden the reach of university education to the general public and students from other universities. Changes such as a decrease in the school-age population and a reorganization of the university structure have also created an opportunity to change the perception of online education. In this paper, we conducted surveys on K University students, high school seniors, and the general public to assess their satisfaction with online courses, identify areas that require massive online courses, and determine students' needs for the operation of massive online courses. The survey showed that K University students are generally satisfied with online courses. However, improvements are needed to ensure a smooth online course-taking environment, increase system uniformity, and enhance the overall online course environment. High school students have a strong preference for natural science and should be offered online courses in subjects such as mathematics and physics as prerequisites to prepare for their major classes. The general public prefers the humanities, which is evident in the purpose of the liberal arts lectures.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.992-1001
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• 2023

OWEC (Overtopping Wave Energy Converter) is a wave power generation system using the wave overtopping. The performance and safety of the OWEC are affected by wave characteristics, such as wave height, period. To mitigate this issue, optimal OWEC designs based on wave characteristics must be investigated. In this study, the environmental conditions along the Ulleungdo coast were used. The hydraulic efficiency of the OWEC was calculated using SPH (Smoothed Particle Hydrodynamics) by comparing 4 models that changed the substructure. As a result, it was possible to change the substructure. Through design optimization, a new truss-type structure, which is a substructure capable of carrying the design load, was proposed. Through a case study using member diameter and thickness as design variables, structural safety was secured under allowable stress conditions. Considering wave load, the natural frequency of the proposed structure was compared with the wave period of the relevant sea area. Harmonic response analysis was performed using wave with a 1-year return period as the load. The proposed substructure had a reduced response magnitude at the same exciting force, and achieved weight reduction of more than 32%.

• Korean Journal of Remote Sensing
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• v.39 no.5_2
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• pp.755-770
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• 2023

Due to recent severe climate change, abnormal weather phenomena, and other factors, the frequency and magnitude of natural disasters are increasing. The need for disaster management using artificial satellites is growing, especially during large-scale disasters due to time and economic constraints. In this study, we have summarized the current status of next-generation medium-sized satellites and microsatellites in operation and under development, as well as trends in satellite imagery analysis techniques using a large volume of satellite imagery driven by the advancement of the space industry. Furthermore, by utilizing satellite imagery, particularly focusing on recent major disasters such as floods, landslides, droughts, and wildfires, we have confirmed how satellite imagery can be employed for damage analysis, thereby establishing its potential for disaster management. Through this study, we have presented satellite development and operational statuses, recent trends in satellite imagery analysis technology, and proposed disaster response strategies that utilize various types of satellite imagery. It was observed that during the stages of disaster progression, the utilization of satellite imagery is more prominent in the response and recovery stages than in the prevention and preparedness stages. In the future, with the availability of diverse imagery, we plan to research the fusion of cutting-edge technologies like artificial intelligence and deep learning, and their applicability for effective disaster management.

• Korean Journal of Remote Sensing
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• v.39 no.5_2
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• pp.743-754
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• 2023

The global occurrence of myriad natural disasters and incidents, catalyzed by climate change and extreme meteorological conditions, has engendered substantial human and material losses. International organizations such as the International Charter have established an enduring collaborative framework for real-time coordination to provide high-resolution satellite imagery and geospatial information. These resources are instrumental in the management of large-scale disaster scenarios and the expeditious execution of recovery operations. At the national level, the operational deployment of advanced National Earth Observation Satellites, controlled by National Geographic Information Institute, has not only catalyzed the advancement of geospatial data but has also contributed to the provisioning of damage analysis data for significant domestic and international disaster events. This special edition of the National Disaster Management Research Institute delineates the contemporary landscape of major disaster incidents in the year 2023 and elucidates the strategic blueprint of the government's national disaster safety system reform. Additionally, it encapsulates the most recent research accomplishments in the domains of artificial satellite systems, information and communication technology, and spatial information utilization, which are paramount in the institution's disaster situation management and analysis efforts. Furthermore, the publication encompasses the most recent research findings relevant to data collection, processing, and analysis pertaining to disaster cause and damage extent. These findings are especially pertinent to the institute's on-site investigation initiatives and are informed by cutting-edge technologies, including drone-based mapping and LiDAR observation, as evidenced by a case study involving the 2023 landslide damage resulting from concentrated heavy rainfall.

• Journal of Korea Water Resources Association
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• v.56 no.10
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• pp.641-653
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• 2023

As climate change and urbanization are causing unprecedented natural disasters in urban areas, it is crucial to have urban flood predictions with high fidelity and accuracy. However, conventional physically- and deep learning-based urban flood modeling methods have limitations that require a lot of computer resources or data for high-resolution flooding analysis. In this study, we propose and implement a method for improving the spatial resolution of urban flood analysis using a deep learning based super-resolution technique. The proposed approach converts low-resolution flood maps by physically based modeling into the high-resolution using a super-resolution deep learning model trained by high-resolution modeling data. When applied to two cases of retrospective flood analysis at part of City of Portland, Oregon, U.S., the results of the 4-m resolution physical simulation were successfully converted into 1-m resolution flood maps through super-resolution. High structural similarity between the super-solution image and the high-resolution original was found. The results show promising image quality loss within an acceptable limit of 22.80 dB (PSNR) and 0.73 (SSIM). The proposed super-resolution method can provide efficient model training with a limited number of flood scenarios, significantly reducing data acquisition efforts and computational costs.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.41 no.4
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• pp.1-7
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• 2023

Chwibyeong is a hedge made into a folding screen shape by setting up supports and placing plants on it. Traces of chwibyeong can be found in various paintings, such as the 『Donggwoldo painting of Changdeokgung Palace』, 『Gyujanggak painting』, 『Munhuimyo painting』, and 『Hwaseong Temporary Palace painting depicting Suwon Hwaseong Temporary Palace』. However, since the Chwibyeong has not survived to this day, the whereabouts of the Chwibyeong were estimated through ancient documents, old paintings, and photographs. In the case of a manned Chwibyeong using a support, a picture related to the composition of the Chwibyeong using a base can be Winnow willow. Methods for creating intoxicants using coniferous trees such as Chinese juniper and Rigid-branch yew have been studied. In existing old paintings, only the supports, parts of leaves, and branches were depicted, so the location of the Chwibyeong could not be confirmed through the drawings. However, in the 『Jungli-Euiguae』, written around 1797, a manned type of Chwibyeong using a support was depicted as the material of the Chwibyeong. By being able to confirm the type of tree used, it was possible to confirm the method of creating a Chwibyeong using Winnow willow introduced in the 『LimwonGyeongjeji』. However, in the 『Jungli-Euiguae』, written around 1797, a manned type of Chwibyeong using a support was depicted as the material of the Chwibyeong. By being able to confirm the type of tree used, it was possible to confirm the method of creating a Chwibyeong using Winnow willow introduced in the 『LimwonGyeongjeji』. Therefore, the purpose of this study is to suggest a method of using Chwibyeong to restore by analyzing old literature. For this purpose, first, the process of change in the material of the Chwibyeong was analyzed through the analysis of old documents showing the method of forming the Chwibyeong. Second, the material and composition method of the Chwibyeong were analyzed through the analysis of the picture of "Seongyeok-do" in 『Jungli-Euiguae』, which allows us to understand the form of the Chwibyeong

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.85-91
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• 2023

In this study, an experimental study was conducted on the flame behavior, combustion dynamics, and NOx emission characteristics for hydrogen co-firing with the EV burner which is the first stage combustor of GT24. It was confirmed that as the hydrogen co-firing rate increases, the NOx emission increases. This change was elucidate to be the result of a combination of changes in penetration depth due to changes in fuel density, reduction in fuel mixing due to changes in flame position due to increased flame propagation speed, and oscillation of fuel mixedness due to combustion instability. Through pressurization tests in the range of 1.3 to 3.1 bar, NOx emission characteristics under high-pressure operating conditions were predicted, and based on this, the hydrogen co-firing limits of the EV burner was evaluated.

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.178-188
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• 2024

The dynamics of suspended sediment (SS) in forested catchments vary depending upon human or natural disturbances, including land use change, forestry activity, forest fires, and landslides. Understanding the dynamics of SS originating from the potential sources within a forested catchment is crucial for establishing an effective water quality management strategy. Therefore, to suggest a systematic method for interpreting SS dynamics, we evaluated the performance and applicability of ten methods for calculating the hysteresis index based on observed hydrological data and two calculation models (Lawler's method and Lloyd's method) with five sampling intervals (50th, 25th, 10th, 5th, and 1st percentiles). Our results showed that Lloyd's method, which used a sampling interval at the 1st percentile, had the largest number of analyzable runoff events and exhibited the best performance. The results of this study can contribute to quantifying the hysteresis in the relationship between discharge and SS and provide useful information for interpreting SS dynamics.

• Journal of Ecology and Environment
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• v.47 no.4
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• pp.282-289
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• 2023

Background: As wildlife habitats are being destroyed and growth environments are changing, the survival of animals and plants is under threat. Epilobium hirsutum L., a species that inhabits wetlands, has held legally protected status since 2012. However, no specific measures are currently in place to protect its habitat, leading to a decline in remaining populations as a result of land use change and human activities. Results: The growth environment (including location, climate, land use, soil, and vegetation) of the five habitat sites (Samcheok, Taebaek1, Taebaek2, Cheongsong, Ulleung) of E. hirsutum L. was investigated and analyzed. These habitats were predominantly situated in flat areas with gentle south-facing slopes, at an average altitude of 452.7 m (8-726 m) above sea level in Gangwon-do and Gyeongsangbuk-do. The average annual temperature ranged 11.5℃ (9.2℃-12.9℃), whereas the average annual precipitation ranged 1,304.5 mm (1,062.7-1,590.7 mm). The surrounding land use status was mainly characterized by mountainous areas, and human interference, such as agricultural land and roads, was commonly found in proximity to these natural habitats. Soil physicochemical analysis revealed that the soil was predominantly sandy loam with a slightly high sand content. The average pH measured 7.64, indicating an alkaline environment, and electrical conductivity (EC) averaged 0.33 dS/m. Organic matter (OM) content averaged 66.44 g/kg, available phosphoric acid (P₂O₅) content averaged 115.73 mg/kg, and cation exchange capacity (CEC) averaged 23.43 cmolc/kg. The exchangeable cations ranged 0.09-0.43 cmol⁺/kg for potassium (K), 10.23-16.21 cmol⁺/kg for calcium (Ca), 0.67-4.94 cmol⁺/kg for magnesium (Mg), and 0.05-0.74 cmol⁺/kg for sodium (Na). The vegetation type was categorized as E. hirsutum community with high numbers of E. hirsutum L., Persicaria thunbergii (Siebold & Zucc.) H. Gross, Phragmites japonica Steud., Humulus japonicus (Siebold & Zucc.), and Bidens frondosa L.. An ecological flora analysis, including the proportion of lianas, naturalized plants, and annual herbaceous plants, revealed that the native habitat of E. hirsutum L. was ecologically unstable. Conclusions: Analysis of the habitat of E. hirsutum L., a class II endangered wildlife species, provided essential data for local conservation and restoration efforts.