• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.3
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• pp.417-422
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• 2022

It is always desirable that the continuation of power flow through the lines should not be interrupted for a long time. The optimized guideline of reclosers on distribution lines is known to improve the reliability of power systems, the protection functions on distribution systems heavily rely on the number and placement of such reclosers. This study reviewed the effect of using protection settings methodology with the number of reclosing operations to reduce the damage sustained during faults on distribution networks. The aim of the study is to determine the number of reclosing operations and fault current conditions based on simulation data of PSCAD/EMTDC for standard distribution networks. It is found that the determination of the number of operations on reclosers, which are the protection function of feeders, helped to optimize the operation and reliability of distribution networks.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.110-117
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• 2023

In this paper, the optimal placement of the rotary wing's communication and navigation antennas was evaluated by measuring their performance through ground simulations and flight tests. To select the mounting position of the communication and navigation antenna on the helicopter, after considering the shape and characteristics of the airframe, the radiation patterns, coupling analysis, equipment operation profiles, and antenna type analysis were performed for the aircraft-mounted antenna. Based on the analysis results, a procedure for sequentially performing voltage standing wave ratio (VSWR) measurement and antenna pattern test was established through ground and flight tests of the antenna. The systematic performance measurement method and procedure proposed in this paper were verified through ground and flight tests of the Light Armed Helicopter (LAH) system.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.353-353
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• 2022

본 연구에서는 CMIP5(The fifth phase of the Couple Model Intercomparison Project) 미래기후시나리오와 LSTM(Long Short-Term Memory) 모형 기반의 딥러닝 기법을 이용하여 하천유량 예측을 위한 최적 학습 기간을 제시하였다. 연구지역으로는 진안군(성산리) 지점을 선정하였다. 보정(2000~2002/2014~2015) 및 검증(2003~2005/2016~2017) 기간을 설정하여 연구지역의 실측 유량 자료와 LSTM 기반 모의유량을 비교한 결과, 전체적으로 모의값이 실측값을 잘 반영하는 것으로 나타났다. 또한, LSTM 모형의 장기간 예측 성능을 평가하기 위하여 LSTM 모형 기반 유량을 보정(2000~2015) 및 검증(2016~2019) 기간의 SWAT 기반 유량에 비교하였다. 비록 모의결과에일부 오차가 발생하였으나, LSTM 모형이 장기간의 하천유량을 잘 산정하는 것으로 나타났다. 검증 결과를 기반으로 2011년~2100년의 CMIP5 미래기후시나리오 기상자료를 이용하여 SWAT 기반 유량을 모의하였으며, 모의한 하천유량을 LSTM 모형의 학습자료로 사용하였다. 다양한 학습 시나리오을 적용하여 LSTM 및 SWAT 모형 기반의 하천유량을 모의하였으며, 최적 학습 기간을 제시하기 위하여 학습 시나리오별 LSTM/SWAT 기반 하천유량의 상관성 및 불확실성을 비교하였다. 비교 결과 학습 기간이 최소 30년 이상일때, 실측유량과 비교하여 LSTM 모형 기반 하천유량의 불확실성이 낮은 것으로 나타났다. 따라서 CMIP5 미래기후시나리오와 딥러닝 기반 LSTM 모형을 연계하여 미래 장기간의 일별 유량을 모의할 경우, 신뢰성 있는 LSTM 모형 기반 하천유량을 모의하기 위해서는 최소 30년 이상의 학습 기간이 필요할 것으로 판단된다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.265-275
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• 2023

The purpose of this paper is to devise an optimal route allocation algorithm for automated vehicle(AV) in monitoring quality of road infrastructure to support the road safety. The tasks of an AV in this paper include visiting node-links at least once during its operation and checking status of road infrastructure, and coming back to its depot.. In selecting optimal route, its priority goal is visiting the node-links with higher risks while reducing costs caused by operation. To deal with the problem, authors devised reward maximizing algorithm for AVs. To check its validity, the authors developed simple toy network that mimic node-link networks and assigned costs and rewards for each node-link. With the toy network, the reward maximizing algorithm worked well as it visited the node-link with higher risks earlier then chinese postman route algorithm (Eiselt, Gendreau, Laporte, 1995). For further research, the reward maximizing algorithm should be tested its validity in a more complex network that mimic the real-life.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.302-302
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• 2022

최근 태풍, 집중호우로 인한 홍수피해가 빈번히 발생함하고 있다. 특히 상류에 저수지가 있을 경우 홍수조절을 통해 하류지역의 홍수피해를 저감하기도 하지만 급작스런 방류량의 증가 등으로 인해 하류지역의 피해가 증가되는 경우도 있다. 따라서 하류지역 홍수피해 저감을 위해 저수지의 홍수관리기능에 대한 관심도가 높아지고 있다. 대규모 다목적댐의 경우 다양한 저수지운영룰을 통해 수문을 운영하고 있어 홍수조절기능을 충분히 수행하고 있지만, 농업용저수지는 홍수관리에 있어 수문조작 전문성의 부족과 운영룰의 미정립 등으로 인해 취약성을 가지고 있는 상황이다. 본 연구에서는 수문이 설치된 1백만m³이상의 저수지 중 성주저수지를 연구대상저수지로 선정하였다. 비상수문을 통한 사전방류방안과, 저수지운영을 연구하여 농업용저수지의 홍수조절용량 확보를 위한 사전방류방안에 대해 연구하였다. 저수지운영은 Auto ROM을 적용하였고 홍수조절용량 확보를 위하여 홍수기 수위관리기법 중 사전방류기법을 채택하였다. 사전방류기법은 모의기법에 의한 사전방류와 최적화기법에 의한 최적사전방류량을 결정하는 방법으로 연구하였다. 홍수기의 제한수위는 유효저수량의 70%인 EL.179.7m, 65%인 EL.178.8m, 60%인 EL.177.8m로 설정하여 분석하였다. 모의기법에 의한 사전방류방법은 초기수위는 만수위에서부터 1.0m씩 감소하였고, 비상수문은 0.5m씩 개방하여 4.0m까지 개방 하였다. 사전방류의 시간은 24hrs, 48hrs를 적용하였다. 최적화기법에 의한 사전방류방법은 초기수위는 모의기법과 동일하고 목표수위를 제한수위(70%, 65%, 60%)가 되는 최적방류량을 산정하고 최적방류량을 방류할 수 있는 수문의 개방높이를 분석하였다. 2012년, 2020년의 호우사상에 대해 사전방류가 없는 경우와 모의기법, 최적화기법에 의한 사전방류결과를 적용한 경우를 비교하여 검토하였다. 그 결과 제한수위 70%를 유지할 경우 2012년은 모의기법이 5.6%, 최적화기법이 5.4%의 방류량 감소효과가 있으며 2020년은 모의기법이 9.0%, 최적화기법이 8.8%의 방류량 감소효과가 있는 것으로 검토되었다.

• Korean Journal of Agricultural Science
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• v.15 no.2
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• pp.153-163
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• 1988

This experiment was carried out to obtain the thermophilic fungus producing amylase and to investigate properties of the amylase. The selected strain, L-11 was obtained from soil in the vicinity of a hot spring and identified as Mocor sp.. And then the conditions for enzyme production in wheat bran cultures and properties of the crude enzyme were investigated. Furthermore, the enzyme was purified and the characteristics of purified enzyme were studied. The results obtained were as follows: 1. On the wheat bran medium added 80-100% water, amylase was effectively produced by the selected strain, L-11 for 48 hrs incubation at $50^{\circ}C$. 2. When the crude enzyme solution of the strain L-11 was passed through DEAE-Sephadex A-50 column chromatography, two peaks having amylase activity were obtained, and one peak was that of the main enzyme (enzyme of B peak). 3. The purified enzyme (enzyme of B peak) was recognized as single protein band on polyacrylamide disc gel electrophoresis. 4. In the hydrolysis reaction of soluble starch by the enzyme of main amylase, oligosaccharides produced at early stage were maltose and maltotriose mainly and procedure of the reaction maltose amount of maltose and glucose was increased. 5. The strain L-11 was recognized as a special strain producing ${\alpha}-amylase$ mainly and scarcely glucoamylase. 6. The optimum pH, optimum temperature, pH stability, and temperature stability of ${\alpha}-amylase$ were pH 4.0, $60-65^{\circ}C$, pH 4.0-9.0, and below$70^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.217-225
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• 2004

This study was carried out to reduce the loss of frozen dough quality during frozen storage. Using response surface method, ascorbic acid 160.4 ppm, L-cysteine 63.1 ppm, and SSL 0.6% were found to be optimum, with xanthan gum 0.3% (formula A) and Ultra tex-3 5% (formula B) added as cryoprotectants. During frozen storage at $-20^{\circ}C$, control rapidly deteriorated after 4 weeks, while formulas A and B showed slight deterioration with immutable quality after 10 weeks.

• Applied Biological Chemistry
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• v.11
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• pp.83-88
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• 1969

94 Cellulase producing strains were isoated from soils, composts, rotten woods and straws, and gastric contents and feces of herbivorous animals in various places. Among them, the strain MC-9, MC-10, MC-53 and MC-61 were found to be highly active in the degradation of carboxy methyl cellulose. Their cultural conditions adequate for the cellulase formation and effects of inorganic salts and various organic substances added to the wheat bran media were investigated. The results obtained are as follows; 1. Optimum conditions for the cellulase formation were MC-9: pH 5.5, temp. $35^{\circ}C$, incubation time 5 days, MC-10: pH 5.5-6.0, temp. $30^{\circ}C$, incubation time 5 days, MC-53: pH 3.5, temp. $30^{\circ}C$, incubation time 5 days, MC-61: pH 3.5-4.0, temp. 30-$35^{\circ}C$, incubation time 5 days. 2. Their cellulase activity in their optimum conditions were MC-9: CMC-LP(liquefying power). 87.7%, CMC-SP(saccharifying power) 3.20 glucose mg./gm. of the cultures/min., MC-10: CMC-LP 82.9%, CMC-SP 2.48 glucose mg./gm. of the cultures/min., MC-53: CMC-LP 72.4%, CMC-SP 1.76 glucose mg./gm. of the cultures/min., MC-61: CMC-LP 87.1%, CMC-SP 2.08 glucose mg./gm. of the cultures/min. 3. Additions of inorganic salts to the wheat bran media were not significant for the cellulase formation, but additions of soybean film and orange-peel pomace promoted the CMC-liquefying power 3 to 5 percent in wheat bran cultures of the strains.

• Clean Technology
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• v.28 no.1
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• pp.79-93
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• 2022

In this study, an electronics industrial wastewater activated sludge model (e-ASM) to be used as a Water Digital Twin was calibrated based on real high-tech electronics industrial wastewater treatment measurements from lab-scale and pilot-scale reactors, and examined for its treatment performance, effluent quality prediction, and optimal process selection. For specialized modeling of a high-tech electronics industrial wastewater treatment system, the kinetic parameters of the e-ASM were identified by a sensitivity analysis and calibrated by the multiple response surface method (MRS). The calibrated e-ASM showed a high compatibility of more than 90% with the experimental data from the lab-scale and pilot-scale processes. Four electronics industrial wastewater treatment processes-MLE, A2/O, 4-stage MLE-MBR, and Bardenpo-MBR-were implemented with the proposed Water Digital Twin to compare their removal efficiencies according to various electronics industrial wastewater characteristics. Bardenpo-MBR stably removed more than 90% of the chemical oxygen demand (COD) and showed the highest nitrogen removal efficiency. Furthermore, a high concentration of 1,800 mg L^-1 T MAH influent could be 98% removed when the HRT of the Bardenpho-MBR process was more than 3 days. Hence, it is expected that the e-ASM in this study can be used as a Water Digital Twin platform with high compatibility in a variety of situations, including plant optimization, Water AI, and the selection of best available technology (BAT) for a sustainable high-tech electronics industry.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.302-311
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• 1995

Benfuresate or oxolinic acid, as an experimental pesticide, was applied to the different textural paddy or upland soil respectively under the field condition and the residual concentrations were determined. Six kinetic models were employed to characterize the best-fit kinetic model describing the residual pattern of benfuresate or oxolinic acid and the $t\frac{1}{2}$ estimated from each model was comparatively assessed. All of the six models explained significantly the residual patterns of the pesticides but the empirical models such as PF, EL, and PB were not recommendable for the $t\frac{1}{2}$ estimation. Among theoretical models, the residual patterns were followed in the orders of the second-order(SO)>first-order(FO)>zero-order(ZO) kinetics, judging from the size and significance of coefficient of determination and standard error. However, the multiple FO model, consisting of the fast and slow decomposition steps, was better than the single FO model for the residual pattern and the $r^2$ in this case became similar to that of SO kinetic model. Thus the multiple FO and SO models were represented as the best fit model of the experimental pesticide. The $t\frac{1}{2}$ of benfuresate estimated from the single FO kinetic model in Weolgog and Cheongwon series was 49 and 63 days, respectively, which were 20 and 13% longer than the respective $t\frac{1}{2}$ from the SO kinetic model. The $t\frac{1}{2}$ of oxolinic acid from the FO model in Yonggye and Ihyeon series were 87 and 51% longer than those from the SO kinetic model, respectively. These results demonstrated that the best-fit model representing the residual pattern of a pesticide and the resultant $t\frac{1}{2}$ might be variable with the kinds of pesticides and the environmental conditions. Therefore it is recommended that the half-life of a pesticide be assessed from the best-fit model rather than from the FO kinetic model uniformly.