• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.19-32
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• 2021

In this study, evaluation and consideration of domestic/overseas design, construction, and quality control performed by the authors on the deep cement mixing method were performed, and improvements for the development of the DCM method were suggested in the future. As a result of this study, it was found that the cross-sectional area correction for strength is required during the laboratory test of mix proportion, and caution is required because the extrapolation method may lead to different results from the actual one. Applicable design methods should be selected in consideration of both the improvement ratio and the type of improvement during design, and it was confirmed that the allowable compressive strength to which the safety factor was applied refers to the standard value for stability review and not the design parameters. In the case of the stress concentration ratio, rather than applying a conventional value, it was possible to perform economical design by calculating the experimental and theoretical stress concentration ratio reflecting the design conditions. In the case where pre-boring is expected during construction, if the increased water content is not large compared to the original, there were cases where a major problem did not occur even if the result that did not consider the increase in water content was used. In addition, it was confirmed that when the ratio of the top treatment length to the improved length is high, a small amount of design cement contents per unit length can be injected during construction. In the case of quality control, it was evaluated that D/4~2D/4 for single-axis and D/4 point for multi-axis were optimal for coring of grouting mixtures. As an item for quality control, it is judged that the standard that considers the TCR along with the unconfined compressive strength of grouting mixtures is more suitable for the domestic situation.

• Journal of Nutrition and Health
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• v.55 no.3
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• pp.330-347
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• 2022

Folate, a water-soluble vitamin, acts as a coenzyme for one-carbon metabolism in nucleic acid synthesis and amino acid metabolism. Adequate folate nutritional status during the periconceptional period is known to prevent neural tube defects. In addition, insufficient folate intake is associated with various conditions, such as anemia, hyperhomocysteinemia, cardiovascular disease, cancer, cognitive impairment, and depression. This review discusses the rationale for the revision of the 2020 Korean dietary reference intakes for folate, and suggestions for future revisions. Based on the changes in the standard body weight in 2020, the adequate intake (AI) for infants (5-11 months) and the estimated average requirements (EARs) for 15-18 years of age were revised, but there were no changes in the recommended nutrient intakes (RNIs) and tolerable upper intake levels (ULs) for all age groups. Mean folate intake did not reach RNI in most age groups and was particularly low in women aged 15-29 years, according to the results of the 2016-2018 Korea National Health and Nutrition Examination Survey (KNHANES). The percentages of folate intake to RNI were lower than 60% in pregnant and lactating women, but serum folate concentrations were higher than those in other age groups, presumably due to the use of supplements. Therefore, total folate intake, from both food and supplements, should be evaluated. In addition, the database of folate in raw, cooked, and fortified foods should be further expanded to accurately assess the folate intake of Koreans. Determination of the concentrations of erythrocyte folate and plasma homocysteine as well as serum folate is recommended, and quality control of the analysis is critical.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.906-917
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• 2021

This study focused on real estate rental income, which is being interested as a means of preparing for old age in the age of low growth and aging. Rental income is seen to function as a safety net of society at a time when it is necessary to live a difficult old age due to the disconnection of income and the extension of the average life span. Therefore, this study conducted the following study on 1,025 households that own rental real estate nationwide. First, the relationship between the characteristics of the household of the rental real estate owner and the real estate rental income was analyzed, and second, it examined whether there is a difference in rental income between the group that engages in income activities other than rental income and the group that only has rental income without income activities. As a result of the analysis, among the demographic and sociological characteristics, gender and spouse were identified as significant variables in rental income. Among the economic characteristics, income and total debt were found to be significant variables. In the case of income activities, rental income was low, and rental income was high when the total debt was high. However, if interest rates rise and the economic recession is prolonged due to unpredictable causes, the owner may suffer from double-use. In preparation for this, it is necessary to review real estate policy alternatives such as easing the period of real estate holdings.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.801-824
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• 2022

Recently, United Nations found that 38% of global carbon emissions are generated in the building sector, surpassing other industries (32%) and transportation (23%), and ESG is actively used as a way to reduce carbon emissions in the building sector, led by overseas advanced countries. In Korea, as the National Pension Service announced "Consider ESG with more than 50% of investment assets" this year, the move to introduce ESG in the building sector is accelerating, centering on construction companies and asset management companies. However, as the domestic ESG evaluation system is still mainly focused on corporate governance and social responsibility, interest in the environmental sector is lagging behind that of advanced countries. As ESG in the building sector is expected to grow rapidly over the next 10 years, I would like to suggest the following development directions. The first is the expansion of the incentive system. In order for the government to successfully implement policies related to ESG in the building sector, incentive system such as tax reduction and building standards should be expanded further than now in addition to negative systems such as rent restrictions and punishment taxes due to regulatory violations. Second, standardized ESG standards are established. Rather than creating an independent Korean ESG standard that is far from global standards, it is necessary to organize the common parts of global standards and evaluation methods and create and provide guidelines in the form of standard textbooks that can be used equally by all stakeholders. Third, it is an effort to link ESG in the building sector with Digital Transformation(DX). This is because actual energy savings and carbon emission reduction can be realized only when the operation method of the building sector, which is operated mainly by manpower, is digitalized and converted to an intelligent way.

• Journal of Energy Engineering
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• v.23 no.1
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• pp.21-32
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• 2014

This study has analyzed whether the virtuous cycle of value-added between the processes within the company has formed and whether the virtuous ecosystem between the processes within the industry has been built through the analysis of value chain(VC) and value system(VS) targeting the Korean photovoltaic companies. For a study method, after conducting a survey on the companies, a regression analysis was performed on the causal relationship between the process within the VC and VS. Based on the results of the analysis, for the VC of the Korean photovoltaic industry, an increase in the R&D support from the government has led to the increase in the investment of R&D for the related industry, and the increase in the investment of R&D has contributed to the increase in the growth of its productivity, and the growth in the productivity of R&D has influenced the increase in the production of solar products. In addition, the reduction of photovoltaic production cost for the company has influenced the increase of recurring profit margin compared to the sales. However it was shown that the increase in the company's production volume does not contribute to the reduction of production cost. Meanwhile, the increase in recurring profit margin compared to the sales were influencing the increase in the production volume but it was shown that the increase in the company's investment of R&D was not a contributing factor thus it was not included in the virtuous cycle. It was analyzed that the VS was shown not to influence all other processes within the industry except for the module companies where the increase in the recurring profit margin compared to the sales was influenced by the increase in the recurring profit margin compared to the sales of solar cell companies. This shows that the virtuous industrial ecosystem which should be made under the mutual cooperation by the ingot, wafer, solar cell, module and system companies are yet incomplete.

• Journal of Mushroom
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• v.17 no.2
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• pp.52-63
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• 2019

Agrocybe spp. belongs to the Agaricales order, Bolbitiaceae family, and Agrocybe genus. In Korea, so far, it has been cultivated through bottle cultivation; therefore, this study was conducted for the development of a new cultivar using the bag cultivation method for quantitative improvement. Thirty-three gene resources of Agrocybe spp. were collected and their quantity and characteristics of bag cultivation were examined. Next, 5 kinds of crossing parents were selected based on the cultivation period and shape of the fruit body. Seven strains were selected through 3 cross combinations. The 7 selected strains and the comparative cultivar 'Cham' were cultivated in a bag. As a result, the cultivation period was 49 days for 'JBAC15-1' and 50 days for 'JBAC15-6' which are 4 days and 3 days less than the cultivation period of the comparative cultivar 'Cham'(53 days), respectively. Cultivation periods of other strains except for 'JBAC15-1' and 'JBAC15-1' were longer than that of the comparative cultivar'Cham'. The best ratio of primordia formation among the selected strains was found to be that of 'JBAC15-1' with 96.1% followed by 'JBAC15-6' with 94.5%. These rates were 3.1% and 1.5% higher than the ratio of primordia formation of the comparative cultivar 'Cham', which is found to be 93.0%. The quantity was maximum in the 'JBAC15-1' cultivar with 176.8 g per bag followed by 'JBAC15-6' with 168.7 g per bag. The quantities were 10% and 5% more than the comparative cultivar 'Cham' with 160.7 g per bag. Based on these results, 'JBAC15-1' and 'JBAC15-6', which had shorter cultivation periods and more quantities than the comparative cultivar 'Cham' were finally selected. For the selected strains of 'JBAC15-1' and 'JBAC15-6', mycelial growth was observed to be optimal on PDA medium and the optimum temperature was $27.5^{\circ}C$. The optimum pH was pH 5 for 'JBAC15-1' and pH 6 for 'JBAC15-6'. The color of the pileus of the fruit body was dark brown in 'JBAC15-1' and 'Cham' and light brown in 'JBAC15-6'. The pileus was hemispherical in shape in both 'JBAC15-1' and 'Cham'. However, the colors of the stem were different - light brown in 'JBAC15-1', white in 'JBAC15-6', and ivory in the comparative cultivar 'Cham'.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.10
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• pp.678-683
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• 2012

One of alternatives to solve the global water shortages is the reuse of wastewater. The aim of this study was to evaluate whether it can be reused for industrial water from wastewater in "A" City with ultrafiltration (UF) and reverse osmosis (RO) process. The results obtained in this study were that the inorganics such as Na, Mg, Cl, Ca, Mn, $PO_4$, $SO_4$, etc. were removed with high treatment efficiency (more than 97%), respectively. However, the removal of $NH_4$-N, TN, $NO_3$-N, BOD was found to be 35.71%, 85.21%, 87.05% and 56%, respectively. The removal efficiency of nutrients was relatively low compared to other metal ions. Despite low nutrients removal, the treated wastewater is recommended to reuse, because the nutrient contents in influent from the secondary wastewater treatment plant were small amount. In addition, all other metrics in the wastewater were found to be lower amount than wastewater reuse criteria. Therefore, the wastewater treated by UF-RO could be sufficient to reuse for industrial waster.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.2
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• pp.9-15
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• 2011

In this paper, we propose a method to extract the external oblique muscle of abdomen images that is often excluded by previous method due to image distortion. In the preprocessing phase of the proposed method, we emphasize the brightness contrast with Ends-in search stretching algorithm after removing noise from the initial ultrasonic images. Then we apply average binarization in vertical direction to extract candidate fascia areas. After removing other areas than fascia with morphological characteristics, the lost part in the fascia during the process is restored with such characteristic information and location information. Then the skin area is also removed with information from the arc appearing in convex filming and the candidate muscle areas are extracted by overlapping two results two way up-down search algorithm. Another noise removing process is done to determine the muscle area. In case of obtaining obscure result, after restoring the muscle area by smearing method, the thickness of the muscle is measured by min square method. The experiment verifies that the proposed method is sufficiently effective to analyze the size and shape of muscles in abdomen in ultrasonography than previously used methods.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.108.1-108.1
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• 2010

분류층 가스화기는 석탄과 산소(공기) 및 수증기가 반응하여 $1200{\sim}1600^{\circ}C$의 고온, 20~60기압의 고압에서 작동되어 합성가스를 생성하며 합성가스에 포함된 입자 및 황화합물 등을 정제설비를 통하여 정제 후 발전 및 화학원료로 사용한다. 석탄가스화 중 석탄에 포함된 대부분의 회분은 용융슬래그 형태로 가스화기 벽면을 따라 흘러 내려 가스화기 하부의 냉각수조에서 급랭되어 배출된다. 이때 용융슬래그의 원활한 배출을 위해서는 일정범위의 점도를 유지하는 것이 필요하다. 슬래그의 점도는 가스화기 온도 및 Ash의 조성에 따라 크게 변하며 가스화기 설계 및 운전 시 매우 중요한 변수이다. 따라서 최적의 설계 및 운전을 위해서는 Ash의 점도예측이 중요하며, 분류층 가스화기내부에서 Ash 점도 예측을 위한 DooVisco 프로그램을 개발하였다. DooVisco는 가스화기 내부에서 슬래그 용융온도 및 온도별 점도, 가스화기 최소 운전온도 및 석회석 투입 효과 분석뿐만 아니라 석탄의 혼합 사용 시의 특성 예측도 가능하도록 개발되었다. DooVisco는 슬래그 주요 4성분인 SiO2, Al2O3, CaO, FeO 성분에 대한 Phase Diagram을 이용하여 1차적으로 슬래그용융온도(Liquidus Temperature)를 예측하고, 주요 4 성분 외에 Na2O, MgO, K2O, TiO2 등을 고려한 Kalmanovich Model을 이용하여 점도를 예측한다. 최종적으로 슬래그 용융온도와 점도를 활용하여 분류층 가스화기 운전가능 온도범위를 예측한다. 개발된 DooVisco를 활용하여 300MW급 실증 IGCC 플랜트에 사용가능성이 있는 석탄을 대상으로 슬래그의 용융온도 및 점도 등을 예측하였으며 최적 운전을 위한 슬form점도 조절용 Flux인 석회석 투입량 등을 평가하였다. 평가 결과 슬래그 용융온도가 $1700^{\circ}C$ 이상으로 석회석 투입이 필요하다고 판단되었다. 약 가스화기 내부 온도를 $1500^{\circ}C$ 정도에서 원활한 운전을 위해서는 석탄 대비 약 10% 내외의 석회석 투입이 필요할 것으로 평가되었다. DooVisco는 분류층 가스화기 설 계시 가스화기 최적 운전 온도 설정 및 Flux 투입필요성, 종류, 투입량 선정에 활용될 수 있을 뿐만 아니라 플랜트 운전시 석탄의 탄종 적합성 등을 판단하는데 활용될 수 있을 것이라 판단된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.833-839
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• 2019

Bus Information System (BIS) collects information related to the operation of buses and provides information to users through predictive algorithms. Method of predicting through recent information in same section reflects the traffic situation of the section, but cannot reflect the characteristics of the target line. The method of predicting the historical data at the same time zone is limited in forecasting peak time with high volatility of traffic flow. Therefore, we developed a pattern recognition bus arrival time prediction algorithm which could be overcome previous limitation. This method recognize the traffic pattern of target flow and select the most similar past traffic pattern. The results of this study were compared with the BIS arrival forecast information history of Seoul. RMSE of travel time between estimated and observed was approximately 35 seconds (40 seconds in BIS) at the off-peak time and 40 seconds (60 seconds in BIS) at the peak time. This means that there is data that can represent the current traffic situation in other time zones except for the same past time zone.