• Journal of Wetlands Research
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• v.25 no.1
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• pp.35-47
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• 2023

Korean facility horticulture and hydroponic cultivation methods increase, requiring the management of waste water generated. In this study, the amount of fertilizer contained in the discharged waste liquid was determined. By evaluating this as a price, it was suggested to reduce water treatment costs and recycle fertilizer components. It was evaluated based on the results of major water quality analysis of waste liquid by crop, such as tomatoes, paprika, cucumbers, and strawberries, and in the case of P component, it was analyzed by converting it to the amount of phosphoric acid (P₂O₅). The amount of nitrogen (N) can be calculated by discharging 1,145.90kg·ha^-1 of tomatoes, 920.43kg·ha^-1 of paprika, 804.16kg·ha^-1 of cucumbers, 405.83kg·ha^-1 of strawberries, and the fertilizer content of P₂O₅ is 830.65kg·ha^-1 of paprika, 622.32kg·ha^-1 of tomatoes, 477.67kg·ha^-1 of cucumbers. In addition, trace elements such as potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), and manganese (Mn) were also analyzed to be emitted. The price per kg of each item calculated by averaging the price of fertilizer sold on the market can be evaluated as KRW, N 860.7, P 2,378.2, K 2,121.7, Ca 981.2, Mg 1,036.3, Fe 126,076.9, Mn 62,322.1, Zn 15,825.0, Cu 31,362.0, B 4,238.0, Mo 149,041.7. The annual fertilizer loss amount for each crop was calculated by comprehensively considering the price per kg calculated based on the market price of fertilizer, the concentration of waste by crop analyzed earlier, and the average annual emission of hydroponic cultivation. As a result of the analysis, the average of the four hydroponic crops was 5,475,361.1 won in fertilizer ingredients, with tomatoes valued at 6,995,622.3 won, paprika valued at 7,384,923.8 won, cucumbers valued at 5,091,607.9 won, and strawberries valued at 2,429,290.6 won. It was expected that if hydroponic drainage is managed through self-treatment or threshing before discharge rather than by leaking it into a river and treating it as a pollutant, it can be a valuable reusable fertilizer ingredient along with reducing water treatment costs.

• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.246-254
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• 2022

Domestic facility agriculture grows rapidly, such as modernization and large-scale. And the production scale increases significantly compared to the area, accounting for about 60% of the total agricultural production. Greenhouses require energy input to create an appropriate environment for stable mass production throughout the year, but the energy load per unit area is large because of low insulation properties. Through the rooftop greenhouse, one of the types of urban agriculture, energy that is not discarded or utilized in the building can be used in the rooftop greenhouse. And the cooling and heating load of the building can be reduced through optimal greenhouse operation. Dynamic energy analysis for various environmental conditions should be preceded for efficient operation of rooftop greenhouses, and about 40% of the solar energy introduced in the greenhouse is energy exchange for crops, so it should be considered essential. A major analysis is needed for each sensible heat and latent heat load by leaf surface temperature and evapotranspiration, dominant in energy flow. Therefore, an experiment was conducted in a rooftop greenhouse located at the Korea Institute of Machinery and Materials to analyze the energy exchange according to the growth stage of crops. A micro-meteorological and nutrient solution environment and growth survey were conducted around the crops. Finally, a regression model of leaf temperature and evapotranspiration according to the growth stage of leafy vegetables was developed, and using this, the dynamic energy model of the rooftop greenhouse considering heat transfer between crops and the surrounding air can be analyzed.

• The Journal of Engineering Geology
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• v.29 no.4
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• pp.531-539
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• 2019

Various slope protect systems are applied to the slope located around the major facility to maintain stability, and the applied these systems play an important role in protecting the structure by ensuring the safety of the slope. Reinforcement techniques ensure complete safety at the time of application to the slope, but over time, it may become difficult to secure safety. In particular, the deterioration of reinforcement systems may significantly reduce the stability of the slope. Therefore, it is necessary to secure the safety of the slope by defining the necessary items for maintenance of the protect systems and verifying them by the field expert. In this study, a group of experts were formed to determine these items and select their importance among them, and based on their data, the importance of each item was selected by Analytic Hierarchy Process (AHP). The selected items are expected to play an important role in the maintenance of reinforcement systems applied to the slope based on the survey items used by experts.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.1
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• pp.119-130
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• 2018

The VE/LCC study on the existing multi-utility tunnel examined the economical feasibility of the collective area through the cost-benefit analysis of the ten major routes of Seoul for the benefit (7 items) and the cost (5 items) through quantitative methods. In this paper, we analyzed the economic efficiency of 61 sectors by adding 3 items (reduced traffic accident, reduced vehicle noise, social-economic loss). The reduced traffic accident item is an improvement of the traffic accident cost that can be saved by the implementation of the project, and the reduced vehicle noise item is an indicator of the amount of noise change caused by the implement of the business. Finally, the social-economic loss items represent the impact on the local economy due to the construction of the multi-utility tunnel. The amounts of the additional items were compared and items added in the open type and tunnel type multi-utility tunnel were analyzed for each analysis. Result on the analysis, it analyzed the items applied to the basic and detail models in the economic evaluation of the multi-utility tunnel design, and makes it possible to evaluate the economic efficiency more efficiently. The economic evaluation of the basic and detailed models including the items presented in this study will be often used in the design of the multi-utility tunnel design.

• The Journal of Korean Society for School & Community Health Education
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• v.1 no.2
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• pp.17-27
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• 2000

This Study carried out for the purpose of basic data collection school teachers in Korea during September 2000 at Seoul, Kangwon province and JeonRaBuk province. 534 teachers among 600 school health teachers was analyzed by SPSS program. The major findings is as follows; 1. Mean score of Job-satisfaction is $25.52{\pm}4.46$ as 50 total point. Staff cooperation $2.96{\pm}.93$ is the highest score and promotion system $2.02{\pm}1.06$ is the lowest score as 5 total point by Job-satisfaction factor 2. Age-specific mean scores are $20.63{\pm}4.44$ at age of $20{\sim}29$, $25.77{\pm}4.15$ at age of $30{\sim}39$, $27.69{\pm}4.63$ at age of $40{\sim}49$ and $27.11{\pm}5.26$ at age of more than 50. 'Promotion', 'Health education', 'Cooperation of school physician', 'Allocation of professional' and 'Professional skill' are significantly different by age group. 3. Job-satisfaction of long period working teachers is higher than that of short workers, 'Salary system' and 'Professional skill' by factor are significantly different. 4. Job satisfaction by area is not significantly different, and 'Professional skill' as a factor of urban is higher than rural area. 5. Job-satisfaction by school level is not significantly different, and 'Health budget', 'Cooperation of school physician', 'Allocation of professional' and 'Professional skill' are significantly different by level of school. 6. Job-satisfaction of big size school is higher than that of small school and 'Health education' of big size school is high. 7. Job-satisfaction of low education is low score and 'Salary', 'Textbook for health education', 'Health facility' and 'Professional skill' are differnt. 8. 'Educational background', 'Size of school' and 'Level of school' are significantly affected to 'Salary system', this three varialbles explained 13.8% of the total. We can express job -satisfaction of 'Salary system' ; y=2.677-$.182X_6$(Education)+$.120X_5$(Size of school)+$.019X_4$(Level of school) 9. 'Age group', 'Working period' and 'Size of school' are affected to 'Cooperation of school physician', and three variables explain 13.2% of total. We can express job-satisfaction of 'Cooperation of school physician' ; y=2.644+$.247X_1$(Age)+$.179X_2$(Working period)-$.133X_5$(Size of school) 10. 'Working period', 'Education of teacher', and 'Working area' are affected professional skill, this three variables explain 13.5% of job-satisfaction of professional skill. We can express 'Professional skill' ; y=3.076+$.11X_2$(Working period)-$1.06X_6$(Education)-$.126X_3$(Working area). 11. 'Education', 'Age', 'Size of school' and 'Working period' are affected to total job-satisfaction, this four variables explain 14.2% of total satisfaction. We can express job-satisfaction of school health teacher; y=19.76-$.126X_6$(Education)+$.215X_1$(Age)+$.107X_5$(Size of school)+$.121X_2$(Working period).

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1106-1115
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• 2020

Research was conducted on the production of bio-methane for city gas, from food waste digestion gas using two membrane-separation methods(4SBR and 3SDR) in a commercial plant. A purity of 98.9% can be obtained using either method. The recovery rate of methane from the digestion gas was 88.1% for 4SBR and 79.4% for 3SDR. the ratios of bio-methane production to treated digestion gas were 53.5% for 4SBR and 49.4% for 3SDR. However, the 4SBR method had a higher ratio of returned gas(56.5%), approximately twice that of 3SDR, making 3SDR the more desirable method in terms of maximum treat capacity. Therefore, 4SBR seems more economical when the digestion gas to be treated is less than 200 N㎥/day, while 3SDR is more suited to treat gas volumes of more than 240 N㎥/day. The relative deviation of each operation index, compared to mean values, was generally greater for the 4SBR method. Additionally, the correlation coefficients between major system indexes, such as bio-methane production and bio-methane draw out pressure(which is the main control measure of membrane facility) showed that these indexes are more closely related in the 3SDR method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.48-53
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• 2017

One of the policies of the Ministry of Agriculture, Forestry and Livestock Food and Livestock aims to export $10 billion worth of products. Although it was not easy to achieve the export goal of $ 6.5 billion in 2016, the policy should be pursued continuously. Accordingly, a facility modernization project and high-tech greenhouse project are being implemented to facilitate exports. Moreover, it is possible to consider substitution of imports in the policy shift. Imports of temperate and tropical fresh fruits totaled 1.2 trillion won in 2016. Accordingly, identification of alternatives to tropical and temperate fresh fruit imports will enable farm income to increase and the fresh fruit industry to grow. The major obstacle to tropical fruit production in Korea is high heating costs. However, Jeju Island apple mango farmers found that using non-taxable kerosene and hot water from power plants could reduce heating costs by 42.5%. Indeed, using hot wastewater can reduce heating costs by more than 40%. To improve competition with imported fruits, farmers can change their heating systems using financial support plans (e.g., 20% government subsidies, 20% loans, 30% subsidies from local governments). The income effect and import substitution effect of fruit tree farmers should be carefully analyzed in the future and the study will be closed to discuss the policy direction.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.60-69
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• 2012

The project on Geonjisan Universal Design Forest Trail in Jeonju City was designed and constructed by an NGO called 'Jeonbuk Forest for Life' which was a winner for the '2008 Open Competition by the 'Committee for Greening Society' established in Korea Land Corporation. The purpose of this study is to evaluate the design satisfaction of UD forest trail. Post Occupancy Evaluation (POE) method was applied to measure the user satisfaction and the total number of users. The main result of the study were as follows: the major users of the Geonjisan UD forest trail were people aged over 60 years old(37%) and the main purpose of trail usage were to 'walk and rest'(51.5%) and to 'exercise and rehabilitation' (40.6%). Furthermore, the overall user rating for the UD forest trail design was "satisfied"(3.91 point in 5-point Likert Scale). The three most influencing factors of the overall user satisfaction were facility management, user conflict, and trail width and slope. About forty-five people were found to be End-user in the UD forest trail while six people were found as End-user in non-UD trails. Most importantly, the number of End-user observed on the UD forest trail was greater than the number found in non-UD forest trail. The result implies that the UD forest trail attracts more End-users and provides opportunity for gathering and interaction with the other users. Moreover, the satisfaction rate for the UD forest trail landscape is found to be high in Likert scale, which we can assume that the well-grown existing trees and topographic features as well as appropriately designed wood-paths influence the high satisfaction rate of the users. The POE of UD forest trail revealed the importance of universal design concept due to its convenient uses of the handicapped, old, weak, pregnant woman or children.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.1
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• pp.78-88
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• 2018

The purpose of this study is to establish a utilization plan according to the cultural value of Placenta Chamber of King Sejong's Princes. We used SNS to analyze various public perceptions and opinions, collected data and analyzed it. The collection period is from June 01, 2007 to June 30, 2017 (for about 10 years), We gathered data from blogs, cafes, and Knowledge IN that contain keywords related to 'Placenta Chamber', 'Placenta Chamber of Seongju', 'Placenta Chamber of King Sejong's Princes'. and Analyzed using the text mining method of the big date program. Based on the main results of the big data analysis, Placenta Chamber's method of utilization was derived. As a result, major keywords such as King Sejong Great, Prince, Sungju, Feng Shui, culture, preservation, blessing etc were derived. The association of 'world', 'heritage', 'cultural heritage' is high, and the connection of 'Placenta Chamber', 'Gyeongsangbuk-do', 'cultural property' is high, and it was able to confirm the value of Placenta Chamber as a world cultural heritage. and It is necessary to induce visitors to feel stimulation or change of surroundings through facility refurbishment and environmental improvement around Placenta Chamber.

• Journal of Korea Water Resources Association
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• v.55 no.7
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• pp.515-529
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• 2022

Identifying the available water resources amount is an essential process in establishing a sustainable water resources management plan. Dam facility is a major infrastructure storing and supplying water during the dry season, and the water supply yield of the dam varies depending on dam inflow conditions or operation rule. In South Korea, water supply yield of dam is calculated by reservoir simulation based on observed historical dam inflow data. However, the water supply capacity of a dam can be underestimated or overestimated depending on the existence of historical drought events during the simulation period. In this study, probabilistic inflow data was generated and used to estimate the appropriate range of the water supply yield of hydropower dams. That is, a method for estimating the probabilistic dam inflow that fluctuates according to climatic and socio-economic conditions and the range of water supply yield for hydropower dams was presented, and applied to hydropower dams located in the Han river in South Korea. It is expected that the understanding water supply yield of the hydropower dams will become more important to respond to climate change in the future, and this study will contribute to national water resources management planning by providing potential range of water supply yield of hydropower dams.