• Korean Journal of Heritage: History & Science
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• v.55 no.3
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• pp.102-118
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• 2022

Gyeongju, the capital of Silla, is the very essence of the culture and technology of the thousand-year-reign of Silla. However, few studies have been conducted on the landscape sites of the capital of Silla other than Donggung Palace and Wolji Pond, due to the lack of related data. Therefore, this study examined the construction characteristics and nature of the garden pond in Guhwang-dong, whose complete appearance was identified through excavation following Donggung Palace and Wolji Pond. Since the excavation of the garden pond in Guhwang-dong, Gyeongju, there have been disagreements in academia as to whether it is a palace pond or a temple pond of Bunhwangsa Temple. Considering the unique characteristic of the garden pond that it is divided into two periods, it was interpreted that it would have functioned as a ritual facility related to Ryong (oriental dragon) belief in the 6th to 7th centuries, the first period, and as a garden pond with enhanced landscaping functions in the 8th to 9th centuries, the second period. In addition, it is highly probable that it was the site of Cheongyeongung Palace (青淵宮) and Jochujeong Pavilion (造秋亭) mentioned in the literature records. The "ㄹ"- shaped waterway, a characteristic facility of the first period, was found; however, considering its width and depth, it is insufficient to conclude that it was a simple drainage facility. Rather, it is more likely that it functioned as a passageway for the conceptual entry of Ryong during Ryong rituals. Furthermore, some have suggested that it may have been a ceremony-related Yusang-goksu (流觴曲水) facility. These facilities related to Ryong rituals were reorganized in the second period. Specifically, the nature of the garden pond was changed centered on the landscaping function in connection with the addition of a curved revetment, garden stone, and pavilion buildings, and the dismantlement of the "ㄹ"-shaped waterway and hexagonal building. As for nature, it can be regarded as a royal facility in terms of decorative elements including the ritual function of the first period and the gwimyeonwa (ghost face tiles) of the second period. Judging from the fact that the upper part of the embankment adjacent to the west side of the site was removed, it is very apparent that the main building was located on the upper part of the embankment. There would not have been a large-scale building site because it served the functions of ritual and recreation, rather than being the residence of the king.

• Journal of the Korean Orthopaedic Association
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• v.56 no.6
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• pp.484-490
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• 2021

Purpose: A rheumatoid forefoot deformity includes severe hallux valgus and claw toe of the four lateral toes. The authors intended to analyze the mid-term results of the modified Hoffman procedure for a rheumatoid forefoot deformity. Materials and Methods: Twenty-two feet of eighteen patients were followed up for more than two years after the modified Hoffman procedure. The mean age was 54.7 years, and the mean follow-up period was three years and four months. Clinically visual analogue scale (VAS) and American Orthopaedic Foot and Ankle Society (AOFAS) MP-IP score were analyzed preoperatively and postoperatively. The postoperative complications, the satisfaction of patients, and the presence of plantar callosity were also analyzed. Radiographically, the hallux valgus angle, the 1st intermetatarsal angle, the 1st interphalangeal angle, the 1st interphalangeal joint arthritic change after the operation, and the dorsiflexion angle and the time to union of the 1st metatarsophalangeal joint were analyzed. Results: Clinically, the VAS and AOFAS score were respectively improved from 7.1 points and 30.3 points preoperatively to 1.5 points and 83.1 points postoperatively (p<0.001). All patients were satisfied with the results. Plantar callosity disappeared in all cases. Radiographically, the mean hallux valgus angle, the 1st intermetatarsal angle, and the 1st interphalangeal angle changed from 52.8°, 13.3°, and 7.5° preoperatively to 16.2°, 8.7°, and 14.6° postoperatively (p<0.001). The mean dorsiflexion angle of the 1st metatarsophalangeal joint was 17.2° postoperatively. The mean time to radiographic union of the 1st metatarsophalangeal joint was 11.1 weeks. There were two cock-up deformities of the lesser toe, one wound problem, and two hallux interphalangeal joint arthritis as a complication. There were no cases of nonunion of the 1st metatarsophalangeal joint. Conclusion: The modified Hoffman procedure appears to be a safe and satisfactory procedure for a rheumatoid forefoot deformity.

• Economic and Environmental Geology
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• v.55 no.5
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• pp.511-519
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• 2022

In order to develop an air-stripping based remediation process to remove the TOC (Total Organic Carbon) in groundwater around the underground LPG storage cavern, the laboratory scale experiments at various conditions (change of air injection volume and temperature, the application of ultrasonic treatment, etc.) for two types of groundwater (initial TOC concentration of 608 mg/L and 153 mg/L, respectively). From results of experiment, as the air injection rate for stripping into groundwater increased from 2 L/min to 11 L/min and as the air-stripping time increased from 1 hour to 24 hour, the TOC removal efficiency of air-stripping increased. However, the TOC concentration of treated groundwater was higher than the discharge tolerance limit (100 mg/L) even after 24 hour stripping at the maximum air injection rate of 11 L/min. The main compounds of the TOC in groundwater were identified as methanol and propane and the long stripping time (more than 24 hour) was needed to separate the methanol from groundwater because of the affinity between water and methanol. At 20℃ and 4 L/min of air injection, the TOC removal efficiency increased to 59.1% after 24 hour air-stripping. When the temperature of groundwater increased to 30℃ and 40℃, the TOC removal efficiency increased up to 80.0% and 82.8%, suggesting that more than 24 hour air-stripping at 40℃ is needed to lower the TOC concentration to below 100 mg/L and the additional TOC removal process as well as the air-stripping is necessary. When the temperature increased to 60℃ and the ultrasonic treatment was conjugated with the air-stripping, the TOC removal efficiency increased to 87.8% within 5 hour stripping and the final TOC concentration (72.4 mg/L) was satisfied with the TOC discharge tolerance limit. The TOC removal efficiency for groundwater having low TOC concentration (153 mg/L) also showed similar removal efficiency of 89.7% (the final TOC concentration: 18.9 mg/L). Results in this study supported that the air-stripping conjugated with the ultrasonic treatment could remove successfully the TOC in groundwater around the underground LPG strorage cavern.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.2
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• pp.165-170
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• 1994

High quality rapeseed cultivars including Nojeokchae, Yeongsanyuchae Halla-yuchae and Tamrayuchae have been released and recommended as a zero erucic acid variety to Cheju farmers for 13 years, where is a major rapeseed production area in korea. However, rapeseeds produced in Cheju island in 1992 and 1993 contained 47.7% and 37.0% of erucic acid respectively resulting in poor quality oil being not adequate for edible oil. It was considered that the zero erucic acid varieties did not have an opportunity to be cultivated in Cheju island by farmers living in the Island. Thus, the new rapeseed varieties without erucic acid should be bred and recommended to the farmers of southern area of Korea as a multiple cropping crop just after rice harvest, and for large scale mechanized and labour-serving rapeseed culture. The change of rapeseed breeding goal would be desirable for fatty acid composition improvement of rapeseed to develop varieties adaptable to southern part of Korea, and to produce rapeseed oil directly used as an edible oil safely.

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.105-119
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• 2023

Water supply is decreasing due to climate change, and coastal and island regions are highly dependent on groundwater, reducing the amount of available water. For sustainable water supply in coastal and island regions, it is necessary to accurately diagnose the current condition and efficiently distribute and manage water. For a precise analysis of the groundwater flow in the coastal island region, submarine fresh groundwater discharge was calculated for the Seongsan basin in the eastern part of Jeju Island. Two methods were used to estimate the thickness of the fresh groundwater. One method employed vertical interpolation of measured electrical conductivity in a multi depth monitoring well; the other used theoretical Ghyben-Herzberg ratio. The value using the Ghyben-Herzberg ratio makes it impossible to accurately estimate the changing salt-saltwater interface, and the value analyzed by electrical conductivity can represent the current state of the freshwater-saltwater interface. Observed parameter was distributed on a virtual grid. The average of submarine fresh groundwater discharge fluxes for the virtual grid was determined as the watershed's representative flux. The submarine fresh groundwater discharge and flux distribution by year were also calculated at the basin scale. The method using electrical conductivity estimated the submarine fresh groundwater discharge from 2018 to 2020 to be 6.27 × 10⁶ m³/year; the method using the Ghyben-Herzberg ratio estimated a discharge of 10.87 × 10⁶ m³/year. The results presented in this study can be used as basis data for policies that determine sustainable water supply by using precise water budget analysis in coastal and island areas.

• Korean Journal of Environment and Ecology
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• v.37 no.1
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• pp.1-12
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• 2023

We analyzed the distribution area of debris slopes in Mudeungsan (Mt. Mudeung) National Park by comparing aerial photos of the past (1966) and the present (2017) and identified the vegetation characteristics that affect the change in the area of the debris slopes by investigating the vegetation status of the debris slopes and the surrounding areas. The area of debris slopes in Mt. Mudeung appears to have been reduced to a quarter of what it used to be. Debris slopes here have decreased at an average rate of 2.3 ha/yr over 51 years by vegetation covers. Notably, most of the small-area debris slopes in the low-inclination slopes disappeared due to active vegetation coverage. However, there are still west-facing, south-west-facing, south-facing, and large-area debris slopes remaining because the sun's radiant heat rapidly raises the surface temperature of rock blocks and dries moisture, making tree growth unfavorable. Because of these locational characteristics, the small-scale vegetation in the middle of Deoksan Stony Slope, which is the broadest area, showed distinct characteristics from the adjacent forest areas. Sunny places and tree species with excellent drying resistance were observed frequently in Deoksan Stony Slope. However, tree species with high hygropreference that grow well in valleys with good soil conditions also prevailed. In some of these places, the soil layer has been well developed due to the accumulation of fine materials and organic matter between the crevices of the rock blocks, which is likely to have provided favorable conditions for such tree species to settle and grow. At the top of Mt. Mudeung, on the other hand, the forest covered the debris slopes, where Mongolian oaks (Quercus mongolica) and royal azaleas (Rhododendron schlippenbachii), which typically grow in the highlands, prevailed. This area was considered favorable for the development of vegetation for the highlands because the density of rock blocks was lower than in Deoksan Stony Slope, and the soil was exposed. Moreover, ash trees (Fraxinus rhynchophylla) and Korean maple trees (Acer pseudosieboldianum) that commonly appear in the valley areas were dominant here. It is probably due to the increased moisture content in the soil, which resulted from creating a depressive landform with a concave shape that is easy to collect rainwater as rock blocks in some areas fell and piled up in the lower region. In conclusion, the area, density of the rock blocks, and distribution pattern of rock block slopes would have affected the vegetation development and species composition in the debris slope landform.

• Journal of the Daesoon Academy of Sciences
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• v.45
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• pp.69-102
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• 2023

There has been a growing demand for spiritual education in public education in recent years. In fact, the concept of spirituality was included in the national religious curriculum in 2022. However, compulsory spiritual education based on the national curriculum is different from individual or private organization-based spiritual education which can be characterized as voluntary. This article aims to discuss the potential problems that may arise when making spiritual education compulsory in public education. This discussion includes the expansion of spiritual discourse and the scope of spirituality, the contents and examples of spiritual education, and the implications of compulsory spiritual education. My perspective on this topic is that the religious curriculum, being a national curriculum, should be applicable to all schools and learners. The channels for expanding spiritual discourse include studies for measuring each individual's spirituality or religiosity and spiritual tourism. Both exclusive and inclusive spirituality coexist within spiritual discourse. Furthermore, spiritual educators criticize knowledge-based education for its tendency towards romanticization, while overlooking reflective education in national religious curriculum. Additionally, the normative nature inherent in the concept of spirituality is often overlooked, despite the potential recurrence of problems seen in faith-based education. This article suggested that the minimum principle for the nation's religious curriculum should be that "religious or normative knowledge is not to be injected or delivered but rather reflected upon." This principle aims to provide an opportunity for learners to reflect on their religious experiences or lives subjectively. When this principle is applied, spirituality becomes the object of reflection and selection for learners. Above all, learners with reflective thinking skills will be able to live independently, even if their experiences and lives change. We hope that this article will serve as an opportunity to continually reflect on the form of religious education found in public education.

• Economic and Environmental Geology
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• v.56 no.4
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• pp.435-445
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• 2023

A delta is a depositional landform that is formed when sediment transported by a river is deposited in a relatively low-energy environment, such as a lake, sea, or a main channel. Among these, a delta formed at the confluence of rivers has a great importance in river management and research because it has a significant impact on the hydraulic and sedimentological characteristics of the river. Recently, the equilibrium state of the confluence area has been disrupted by large-scale dredging and construction of levees in the Nakdong River. However, due to the natural recovery of the river, the confluence area is returning to its pre-dredging natural state through ongoing sedimentation. The time-series data show that the confluence delta has been steadily growing since the dredging, but once it reaches a certain size, it repeats growth and retreat, and the overall size does not change significantly. In this study, we developed a model to explain the sedimentation-erosion processes in the confluence area based on the assumption that the confluence delta reaches a dynamic equilibrium. The model is based on two fundamental principles: sedimentation due to supply from the tributary and erosion due to the main channel. The erosion coefficient that represents the Nakdong River confluence areas, was obtained using data from the tributaries of the Nakdong River. Sensitivity analyses were conducted using the developed model to understand how the confluence delta responds to changes in the sediment and water discharges of the tributary and the main channel, respectively. We then used annual average discharge of the Nakdong River's tributaries to predict the dynamic equilibrium positions of the confluence deltas. Finally, we conducted a simulation experiment on the development of the Gamcheon-Nakdong River delta using recorded daily discharge. The results showed that even though it is a simple model, it accurately predicted the dynamic equilibrium positions of the confluence deltas in the Nakdong River, including the areas where the delta had not formed, and those where the delta had already formed and predicted the trend of the response of the Gamcheon-Nakdong River delta. However, the actual retreat in the Gamcheon-Nakdong River delta was not captured fully due to errors and limitations in the simplification process. The insights through this study provide basic information on the sediment supply of the Nakdong River through the confluence areas, which can be implemented as a basic model for river maintenance and management.

• Journal of Practical Agriculture & Fisheries Research
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• v.16 no.1
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• pp.37-53
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• 2014

The purpose of this research is to find what difficulties the agricultural successors, the Korea National College of Agriculture and Fisheries (KNCAF) graduates, face with in implementing eco-friendly agriculture in Jeju, and what solutions they can be provided with. This research, a case study on the basis of open-ended survey questions, has 6 cases out of 8 graduates who have or had implemented eco-friendly citrus farming. In Jeju, 24 graduates have involved in citrus farming. According to the case study, only one case was environment-friendly farming method at the pesticide-free level, and the others at organic farming level. All the cases have tried to alter main crops or to diversify management for coping with global climate change and market-opening. On analyzing operating cost to gain product of merchantable quality, it revealed that the environment-friendly farming method needs much more managing efforts than the conventional farming does. But to the contrary, the materials cost in the environment-friendly farming method was lower than in the conventional farming method. In the total production and the price, the environment-friendly farming was 20~50% lower and 10~50% higher than the conventional farming, respectively. Difficulties which the graduates confronted with in implementing the environment-friendly agriculture are as below. Firstly, many of the difficulties have resulted from lack of the environment-friendly farming techniques, and the high cost of farm scale improvement due to high price of land and topographical features of Jeju. Secondly, the agricultural successors, the KNCAF graduates, have trouble in obtaining approval of their parents to changeover from the conventional farming to the environment-friendly farming. Lastly, there is no advisory organizations and experts for environment-friendly farming in the given area. For shift to the environment-friendly farming, followings are needed. Agricultural Technology & Extension center, with cooperation of leading farms in environment-friendly farming, should have a key role in offering education and consults on the environment-friendly farming techniques. Also, this organization should inform rapidly the research results to the farmers, and their feed-back should be involved in the next research. Therefore, it is suggested that the forum called 'Environment-friendly Organic Farming Forum in Jeju' tentatively is organized.

• Journal of Korea Water Resources Association
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• v.56 no.4
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• pp.261-272
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• 2023

In recent years, natural disasters such as heavy rainfall and typhoons have occurred more frequently, and their severity has increased due to climate change. The Korea Meteorological Administration (KMA) currently uses the same criteria for all regions in Korea for watch and warning based on the maximum cumulative rainfall with durations of 3-hour and 12-hour to reduce damage. However, KMA's criteria do not consider the regional characteristics of damages caused by heavy rainfall and typhoon events. In this regard, it is necessary to develop new criteria considering regional characteristics of damage and cumulative rainfalls in durations, establishing four stages: blue, yellow, orange, and red. A classification model, called DSCM (Disaster Severity Classification Model), for the four-stage disaster severity was developed using four machine learning models (Decision Tree, Support Vector Machine, Random Forest, and XGBoost). This study applied DSCM to local governments of Seoul, Incheon, and Gyeonggi Province province. To develop DSCM, we used data on rainfall, cumulative rainfall, maximum rainfalls for durations of 3-hour and 12-hour, and antecedent rainfall as independent variables, and a 4-class damage scale for heavy rain damage and typhoon damage for each local government as dependent variables. As a result, the Decision Tree model had the highest accuracy with an F1-Score of 0.56. We believe that this developed DSCM can help identify disaster risk at each stage and contribute to reducing damage through efficient disaster management for local governments based on specific events.