• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.67-71
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• 1998

This study was carried out to granulate artificial zeolite powder that remove ammonium nitrogen and phosphorous simultaneously in wastewater treatment. Optimum water content was required for 30 percent volume to granulate artificial zeolite with 1.7mm diameter and 1~2cm length using granulator. Portland cement could remove much $NH_4{^+}$ and $PO_4{^{3-}}$ from the wastewater than other binding materials. Mixed 33, 25. 20. 16 percent of portland cement to artificial zeolite powder(v/v), cation exchange capacity of the granulars were 66.5, 81.4, 126.8, $151.2cmol^+kg^{-1}$ and hardness of that were 176.1, 24.4, 4.1, $0.4kg\;cm^{-2}$, respectively. Content of portland cement in the granular were related with removal of $PO_4{^{3-}}$ positively and that of $NH_4{^+}$ negatively. Shaked 1g of the granulars that made of portland cement 33 percent with 40ml synthetic wastewater containing $NH_4{^+}$ $1545mgl^{-1}$ and $PO_4{^{3-}}$ $417mgl^{-1}$, 99.4 percent of $NH_4{^+}$ and 90.3 percent of $PO_4{^{3-}}$ were removed simultaneously after 48 hours shaking. The longer shaking, the more $NH_4{^+}$ and $PO_4{^{3-}}$were removed. The artificial zeolite granular had both micropore and macropore that could be useful in the wastewater purification.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.577-589
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• 2021

Soil seed bank community contributes to the long-term conservation of plant diversity and vegetation dynamics, and their decreasing diversity and density with soil depth provide critical perspectives (deterministic and stochastic) for understanding the community disassembly process. We analyzed changes in species composition and diversity and structuring patterns by soil layer (top and bottom), including surface vegetation, in Gwangneung Forest, a mature forest with a vegetation climate in the temperate central part of the Korean Peninsula. From two layers of soil collected with a vertical difference of 10 cm, 934 specimens of 27 families, 40 genera, 44 species, three varieties, and 47 taxa, germinated. Although species diversity and germination density decreased in most comparative characteristics, including growth type, there was no statistical significance due to large deviations. Within-group variability of species composition was similar in the upper and lower soils, as was the decline pattern in co-occurred species (ζ-diversity) and change in species retention probability. The structuring process of the community composition in the two soil layers was fitted with an exponential correlation rather than a power function, demonstrating the dominance of the stochastic process. The pattern in diversity and species turnover according to soil depth in Gwangneung Forest was discovered to be structured by stochastic random events, such as seed vertical movement rather than interaction with trait characteristics.

• Journal of Applied Biological Chemistry
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• v.64 no.4
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• pp.333-341
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• 2021

In this study, to select strains suitable as microbial agent from among rhizosphere microorganisms present in rhizosphere soil and roots, the mineral solubilization ability, antifungal activity against 10 types of plant pathogenic fungi, and plant growth-promoting activity of rhizosphere microorganisms were evaluated. As a result, DDP346 was selected because it has solubilization ability of phosphoric acid, calcium carbonate, silicon, and zinc; nitrogen fixing ability; production ability of siderophore, indole-3-acetic acid, and aminocyclopropane-1-carboxylate deaminase; and antifungal activity against seven types of plant pathogenic fungi. DDP346 showed a 99.9% homology with Acinetobacter pittii DSM 21653 (NR_117621.1); phylogenetic analysis also revealed a close relationship with Acinetobacter pittii based on the 16S rRNA base sequence. The growth conditions of DDP346 were identified as temperatures in the range of 10-40 ℃, pH in the range of 5-11, and salt concentrations in the range of 0-5%. In addition, a negative correlation coefficient (r² = -0.913, p <0.01) was shown between pH change and the solubilized phosphoric acid content of Acinetobacter sp. DDP346, and this is assumed to be due to the organic acid generated during culture. Consequently, through the evaluation of its mineral solubilization ability, antifungal activity against plant pathogenic fungi, and plant growth-promoting activity, the potential for the utilization of Acinetobacter sp. DDP346 as a multi-purpose microbial agent is presented.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.25-32
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• 2021

In this study, it proposes a mode converter that is relatively easy to implement and can shorten the transmission line length of the final combining port and it was fabricated and tested by applying it to an 8-way spatial combiner. The proposed mode converter converts the signal converted from the doorknob-shaped circular disk connected to the ground into the TM₀₁ mode by opening it in the circular waveguide. The 8-way waveguide spatial combiner is designed and implemented so that 8 signals input from the H-plane are combined in a circular waveguide at the center, and the final combining mode is TM₀₁. The test results confirmed excellent performance with an insertion loss of less than 0.4dB and a combining efficiency of 95% or more. In addition, it was confirmed that it is suitable for high output by calculating the breakdown voltage and discharge threshold power of the new mode conversion structure through electric field analysis. The results confirmed through this study are expected to be applicable to high-power, high-efficiency SSPA in various fields in the future.

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.24-32
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• 2021

Personal Air Vehicle (PAV), Cargo UAS (Cargo UAS), and existing manned and unmanned aircraft are key vehicles for urban air mobility (UAM), and should demonstrate compatibility for the design of aircraft systems. The safety assessment required by for certification to ensure safety and reliability should be systematically performed throughout the entire cycle from the beginning of the aircraft development process. However, with the increasing complexity of safety critical aviation systems and the application of state-of-the-art systems, conventional experience-based and procedural-based safety evaluation methods make ir difficult to objectively assess safety requirements and system safety. Therefore, Model-Based Safety Assessment (MBSA) using modeling and simulation techniques is actively being studied at domestic and foreign countries to address these problems. In this paper, we propose a Model-Based Safety Evaluation framework utilizing modeling and simulation-based integrated flight simulators. Our case studies on the Traffic Collision Availability System (TCAS) and Wheel Brake System (WBS) confirmed that they are practical for future safety assessments.

• The Journal of Bigdata
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• v.6 no.1
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• pp.51-62
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• 2021

In the field of medical artificial intelligence, there have been a lot of researches on disease prediction and classification algorithms that can help doctors judge, but relatively less interested in artificial intelligence that can help medical consumers acquire and judge information. The fact that more than 150,000 questions have been asked about which hospital to go over the past year in NAVER portal will be a testament to the need to provide medical information suitable for medical consumers. Therefore, in this study, we wanted to establish a classification model that classifies 8 medical subjects for symptom text directly described by patients which was collected from NAVER portal to help consumers choose appropriate medical subjects for their symptoms. In order to ensure the validity of the data involving patients' subject matter, we conducted similarity measurements between objective symptom text (typical symptoms by medical subjects organized by the Seoul Emergency Medical Information Center) and subjective symptoms (NAVER data). Similarity measurements demonstrated that if the two texts were symptoms of the same medical subject, they had relatively higher similarity than symptomatic texts from different medical subjects. Following the above procedure, the classification model was constructed using a ridge regression model for subjective symptom text that obtained validity, resulting in an accuracy of 0.73.

• Journal of Teachers' Pension
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• v.4
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• pp.175-205
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• 2019

본 연구의 목적은 폐교로 인해 퇴직한 사립학교 교직원을 대상으로 사학연금의 재해보상기금을 활용하여 실업급여를 제공하는 방안을 모색하는데 있다. 이를 위해 먼저 폐교 퇴직 교직원 현황 및 사학연금에서 폐교로 인한 퇴직 시 연금 지급규정, 재해보상 관련 쟁점, 고용보험 임의가입방안 관련 쟁점 등에 대해 고찰하였다. 다음으로 폐교로 인한 퇴직 교직원에 대한 정책방안들로 현행안, 재해보상기금을 활용한 구직급여 제공방안, 고용보험 임의가입안에 대한 재정추계를 실시하였다. 주요 분석결과는 다음과 같다. 첫째, 불과 5년 뒤인 2024학년도부터는 대입가능자원이 대학입학정원을 크게 밑돌 것으로 전망되고 이로 인해 대학의 통·폐합과 구조조정 등이 발생하여 현재보다 훨씬 더 많은 대학이 폐교될 것으로 예상된다. 둘째, 현행 사학연금법 상연금지급개시연령은 65세이나, 공무원연금법을 준용하고 있는 사학연금에서 폐교로 인해 퇴직하는 경우 퇴직 때부터 5년이 경과한 때 연금을 지급하는 규정으로 인해 여러 문제점들이 발생하고 있다. 셋째, 폐교로 인한 비자발적 퇴직 교직원의 소득활동 중단에 따른 소득 대체 및 생활안정을 위한 방안마련이 시급하다. 넷째, 산재보험과 공무원연금·군인연금 등 공적 재해보상제도들은 모두 업무상 또는 공무상 사고나 질병으로 부상·질병·장해·사망이 발생하면 재해로 정의하고 있어 사학연금에서 폐교를 재해로 포함시키는 것은 적합하지 않으며, 실업에 대응하는 사회보장제도인 고용보험에 포함시키는 것이 보다 타당할 것으로 보인다. 다섯째, 사립학교 교직원에 대한 고용보험적용 여부를 논의하기 위해서는 대학교수의 법적 지위와 근로기준법의 적용가능성이 중요한데, 향후 대법원이 대학교수를 근로기준법상 근로자로 판단한다면 사학 교직원의 고용보험 가입도 가능하게 될 것이다. 여섯째, 사학연금가입자들을 위한 고용보험 도입이 바람직하나, 이것이 단기간 내에 실행되기 어렵다면 고려 가능한 대안으로 공무원연금과는 다른 사학 교직원 직무에서 발생하는 재해의 특성을 고려하여 사학재해보상제도에서 폐교로 인한 퇴직을 재해보상에 포함시키고 구직급여를 제공하는 방안을 검토해 볼 수 있다. 또한 재정추계결과는 다음과 같다. 첫째, 현재 폐교로 인한 퇴직 시 제공되는 연금 대신에 재해보상기금으로 구직급여를 제공할 경우 사학연금기금에 재정적으로 상당히 긍정적 효과가 있을 것으로 예상된다. 둘째, 폐교로 인한 2018년 현재 연금수급자(285명)의 예상 연금급여액 추계에 의하면 2050년까지 누적해서 볼 경우, 재해보상기금을 활용하여 구직급여를 제공하는 방안이 폐교로 인한 퇴직 시 연금을 지급하는 현행안보다 2018년 현재가치로 123억 원 정도 유리한 것으로 나타났다. 셋째, 현재 수급자와 미래 수급자의 예상 연금급여액 추계에 의하면 2028년까지 누적해서 볼 경우, 재해보상기금을 활용하여 구직급여를 제공하는 방안이 현행안보다 2018년 현재가치로 747억 원 정도 재정적으로 유리한 것으로 나타났다.

• The Journal of Engineering Geology
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• v.31 no.3
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• pp.333-342
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• 2021

In this study was conducted to measure the water content and dry unit weight of the ground using TDR (Time Domain Reflectometry) in order to supplement the problems of the conventional compaction management method. The Flat TDR system is a device that does not cause ground disturbance, and in order to verify the measured values, the dry density and water content were measured for samples of the ground subject at 7 sites other than Jumunjin Standard Temple. The water content section was divided into 6 sections of 3, 6, 9, 12, 15, and 18%, and the experimental results were confirmed according to the unified classification method. As a result of the indoor experiment, the water content showed an error of about 0.7% for the SP sample and about 1.3% for the SM sample. In addition, the dry unit weight confirmed an error of about 7% for the SP sample and about 5% for the SM sample. It was confirmed that stable values were derived in sandy or silty sandy ground except for clay or gravel. Through the experimental results, it was confirmed that the measured values of the flat TDR system derive similar values to the existing traditional compaction management method, and it was determined that the flat TDR equipment was suitable for construction sites that require quick constructability and economic feasibility.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.3
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• pp.265-271
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• 2021

Nanoparticles are substances that are smaller in size and smaller than cells that make up the skin. Therefore, they are very suitable as mediators for transmitting drugs or genes across cell membranes, and also deliver specific ingredients into the skin.In this study, nanoparticles were extracted from mugwort and particles of around 100 nm were obtained through dynamic light scattering (DLS), and the results of concentration-dependent enhancement of cell viability in fibroblasts were obtained through MTT assay. In addition, it was confirmed that the COL1A1 mRNA expression level was increased and the IL-6 mRNA expression level was decreased through the quantitative real-time PCR analysis method. Moreover, as these nanoparticles were confirmed to be stable, they can be applied not only to cell experiments but also to cosmetic formulations. While the demand for plant-derived ingredients continues to increase, excluding chemical ingredients from the recent cosmetics industry trend, there is a limitation in that there are few research results suggesting the application field of plant-derived nanoparticles. Therefore, in order to overcome the limitations of the cosmetic industry at the present time, the results obtained in this study present nanoparticles derived from Artemisia princeps (NDAP) as a highly functional cosmetic material.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.379-386
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• 2021

This study was undertaken to develop a cascade-type continuous culture system (CCCS) that combines both ICT and biotechnology (BT), for the mass production of microalgae. This system is capable of maintaining the essential culture conditions of pH, temperature, carbon dioxide, and illuminance control, which are key parameters for the growth of microalgae, and is economical for producing microalgae regardless of the season or location. It has the added advantage of providing stable and high productivity. In the current study, this system was applied to culture microalgae for 71 days, with subsequent analysis of the experimental data. The initial O.D. of the culture measured from incubator 1 was 0.006. On the 71st day of culture, the O.D.s obtained were 0.399 (incubator 1), 0.961 (incubator 2), 0.795 (incubator 3), and 0.438 (incubator 4), thereby confirming the establishment of continuous culture. Thus, we present a smart-farm based on ISMC (in-situ monitoring and control) for a mass culture method. We believe that this developed technology is suitable for commercialization, and has the potential to be applied to hydroponics-based cultivation of microalgae and cultivation of high-value-added medicinal plants as well as other plants used in functional foods, cosmetics, and medical materials.