• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.295-298
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• 1989

Using the anisotropic etching characteristics or $N_2H_4-H_2O$ solution, Si diaphragm was fabricated for the integrated sensor. The optimal composition and temperature of the solution in Si etching process was established to be 50mol% $N_2H_4$ in water at $105{\pm}2^{\circ}C$ for both higher etch rate(=$2.6{\mu}m/min$) and better surface quality of etched {100} planes. Under the optimal etching condition, the electrochemical etch stop technique was employed to form Si diaphragm for pressure sensor and diaphragm thickness was exactly controlled to $20{\pm}2{\mu}m$.

• ETRI Journal
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• 제38권3호
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• pp.529-539
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• 2016

Recently, a product-matrix (PM) framework was proposed to construct optimal regenerating codes for homogeneous distributed storage systems (DSSs). In this paper, we propose an extended PM (EPM) framework for coding of heterogeneous DSSs having different repair bandwidths but identical storage capacities. Based on the EPM framework, an explicit construction of minimum remote-repair bandwidth regenerating (MRBR) codes is presented for a specific heterogeneous DSS, where two geographically different datacenters with associated storage nodes are deployed. The data reconstruction and regeneration properties of the MRBR code are proved strictly. For the purpose of demonstration, an example implementation of MRBR code is provided. The presented MRBR code is the first optimal strict-regenerating code for heterogeneous DSSs. In addition, our proposed EPM framework can be applied to homogeneous systems also.

• 전기학회논문지
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• 제56권2호
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• pp.254-259
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• 2007

PM(Preventive Maintenance) can avail the generating unit to reduce cost and gain more profit in a competitive supply-side power market. So, it is necessary to perform reliability analysis on the power systems in which reliability is essential. Thus, to schedule optimal PM planning based on reliability that is defined RCM(Reliability-Centered Maintenance), FMECA(Failure Mode Effects and Criticality Analysis) assessment is very important. Therefore, in this paper, the procedure of FMECA assessment for optimal RCM is proposed by probabilistic approach using real historical failure data of combustion-turbine generators in Korean power systems. The stochastic FMECA is performed based on the effects of probable failure modes of combustion-turbine generating unit.

• 전기학회논문지
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• 제56권12호
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• pp.2109-2115
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• 2007

The wind generators have been installed with high output power to increase the energy production and efficiency. Hence, Optimal design of the direct-driven PM wind generator, coupled with F.E.M(Finite Element Method) and Genetic Algorithm(GA), has been performed to maximize the Annual Energy Production(AEP) over the whole wind speed characterized by the statistical model of wind speed distribution. Particularly, the parallel computing via internet web service has been applied to loose excessive computing times for optimization. The results of the optimal design of Surface-Mounted Permanent Magnet Synchronous Generator(SPMSG) are compared with each other candidates to verify the usefulness of the maximizing AEP model.

• 한국수정란이식학회지
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• 제21권2호
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• pp.109-119
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• 2006

비글개 6두에서 11회(임신견 7두, 비 임신견 4두)의 발정 주기 및 임신 기간 동안 질 상피 세포 검사 및 혈장 progesterone과 estradiol-$17{\beta}$ 농도를 측정하여 질 상피 세포상과 번식 호르몬의 관계를 조사하고 배란 및 교배 적기 판정을 위한 기초 자료를 제공하고자 본 실험을 실시하였다. 임신 예와 비 임신 예에 있어서 발정 전기, 발정기 및 발정 휴지기의 기간은 각각 $8.5{\pm}1.4(Mean{\pm}SD),\;10.0{\pm}1.4$ 및 $54.0{\pm}2.8$ 그리고 $7.9{\pm}2.1,\;9.5{\pm}0.7$ 및 $62.0{\pm}11.3$일이었다. 임선 예에 비해 비 임신견의 발정 휴지기가 길었으며, 발정 주기 사이의 간격은 임선 예가 $246.2{\pm}24.5$일, 비 임신 예은 $175.3{\pm}34.5$일을 나타내어 임신이 되었던 예가 임신이 되지 않았던 예보다 길었다. 발정 주기별 질 상피 세포상의 변화를 보면 발정 전기와 발정기에는 superficial cell, anuclear cell 및 적혈구가, 발정 휴지기에는 parabasal cell, small intermediate cell, large intermediate cell 및 백혈구가, 그리고 무발정기에는 parabasal cell과 small intermediate cell이 주종을 이루었다. Cornification index(CI)는 발정 주기와 발정기에 유의하게 높았다. 발정 주기 중 혈장 progesterone과 estradiol-$17{\beta}$의 농도 사이의 관계를 혈장 progesterone 농도가 최초로 4.0 ng/ml 이상으로 상승한 날을 기준(Day 0)으로 살펴보면, 혈장 progesterone 농도는 발정 출혈 개시 일에 1.0 ng/ml 이하였으나 Day -2에 2.0 ng/ml 이상으로 상승하였으며, 혈장 progesterone 농도가 최초로 4.0 ng/ml 이상으로 상승한 날은 최초 교배 허용 후 2일이었다. Day 20일 경에 임신 예 및 비임신 예 모두 40 ng/ml 이상으로 최고치를 나타내었으며 Day 35 일까지 임신 예와 비 임신 예 사이에 차이가 인정되지 않았으나 이후 임신 예가 비 임신 예에 비해 높게 유지된 기간이 걸었다. 혈장 estradiol-$17{\beta}$ 농도는 발정 출혈 개시 일에 9 pg/ml 이상을 나타냈으며 이후 급증하여 Day -2 에 26.4 pg/ml로 peak를 나타내었다. CI와 혈장 progesterone 및 estradiol-$17{\beta}$ 농도 사이의 관계를 살펴보면, 혈장 estradiol-$17{\beta}$ 농도는 최초 교배 허용 일(Day 0)에 peak를 나타냈고 혈장 progesterone 농도는 Day 2에 4.0 ng/ml 이상으로 처음 상승하였다. CI 는 혈장 estradiol-$17{\beta}$ peak 이후 l일(Day 1)에 최고치를 나타냈으며 80% 및 90% 이상으로 증가한 날은 각각 Day -1 및 Day 1이었다. CI가 80% 및 90% 이상을 지속한 기간은 각각 Day -1에서 Day 8(10 일간 ) 및 Day 1에서 Day 6(6 일간)이었다. CI가 최고치를 나타낸 후 l일 (Day 2)에 혈장 progesterone 농도가 4.0 ng/ml 이상으로 처음 증가하였다. 결과를 종합하면 본 연구에서 비글개의 배란은 혈장 estradiol-$17{\beta}$ peak 이후 3일 및 혈장 progesterone 농도가 4.0 ng/ml 이상으로 처 음 상승한 날에 일어나며, 교배 적기는 CI가 90% 이상으로 증가한 후 2일 이후와 혈장 progesterone 농도가 $2{\sim}25\;ng/ml$인 시기로 생각된다.

• Applied Biological Chemistry
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• 제51권1호
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• pp.17-23
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• 2008

본 연구는 산머루를 이용한 과실주의 발효시 원료 등에서 기인한 강한 산미에 의한 과실주의 품질을 저하시키는 것을 개선시키기 위하여 혼합균주의 접종에 의한 알코올 발효 과정중 다양한 혼합배양 조건으로 감산발효를 시도하였다. 산머루 알코올 발효균주로 사용된 Saccharomyces sp. SMR-3 배양구에 Schizosaccharomyces pombe와 Schizosaccharomyces japonicus를 각각의 감산발효균주로 접종 후 혼합배양 한 결과, 산머루 알코올 발효균주 Saccharomyces sp. SMR-3에 Schizosaccharomyces pombe를 $22^{\circ}C$, 12일간 혼합 배양한 처리구가 알코올 함량 $15.8{\pm}0.2%$로 최대였고, 산도 $0.44{\pm}0.02%$, 총 유기산 함량 $648.96{\pm}7.14mg%$ , malic acid $99.30{\pm}1.24mg%$ 로 가장 낮게 나타나, 알코올 발효균주 단독으로 배양한 처리구 보다 알코올 함량은 2% 이상 높았고, 산도는 51.65%, 총 유기산은 48.02% 및 malic acid는 81.12%의 감소 효과를 나타내어 최적의 감산발효 조건으로 나타났다.

• Clinical and Experimental Pediatrics
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• 제61권1호
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• pp.6-11
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• 2018

Purpose: Mid-upper-arm circumference (MUAC) is considered an alternative screening method for obesity. The aims of this investigation were to examine the ability of MUAC to correctly identify children with elevated body mass index (BMI) and to determine the best MUAC cutoff point for identification of children with high BMI. Methods: Anthropometric measurements (height, weight, and MUAC) from a cross-sectional sample of 7,921 Pakistani children aged 5-14 years were analyzed. Pearson correlation coefficients between MUAC and other anthropometric measurements were calculated. Receiver operating characteristic curve analysis was used to determine the optimal MUAC cutoff point for identifying children with high BMI. Results: Among 7,921 children, the mean (${\pm}$standard deviation) age, BMI, and MUAC were 10.00 (${\pm}2.86years$), 16.16 (${\pm}2.66kg/m^2$), and 17.73 (${\pm}2.59cm$), respectively. The MUAC had a strong positive correlation with BMI. The optimal MUAC cutoff points indicating elevated BMI in boys ranged from 16.76 to 22.73, while the corresponding values in girls ranged from 16.38 to 20.57. Conclusion: MUAC may be used as a simple indicator of overweight/obesity in children, with reasonable accuracy in clinical settings.

• Membrane and Water Treatment
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• 제9권4호
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• pp.255-262
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• 2018

This study attempted to evaluate the process of self-forming dynamic membrane formation on mesh filter in membrane bioreactor with a two-stage method of batch (agitation) and continues (aeration) stage at different sludge concentrations. Four concentrations of activated sludge including $6{\pm}0.4$, $8{\pm}0.5$, $10{\pm}0.3$, $14{\pm}0.3g/L$ were used to demonstrate the optimal concentration of sludge for treating municipal wastewater and reducing fouling in dynamic membrane bioreactor. The formation time and effluent turbidity were decreased in the batch stage when increasing the activated sludge concentration. The minimum values of formation time and effluent turbidity were 14 min and 43 NTU for the optimum mixed liqueur suspended solids of $8{\pm}0.5g/L$, respectively. To improve operational condition and fouling reduction in the aeration stage, critical fluxes were measured for all concentrations by flux-step method. With increasing the sludge concentration, the relevant critical fluxes reduced. The optimum subcritical flux of $30L/m^2/h$ was applied as operating flux in the second stage. The maximum COD removal efficiency of 98% was achieved by the concentration of $8{\pm}0.5g/L$. Compressibility index of self-forming dynamic membrane and transmembrane pressure trend remained somewhat constant until the optimal concentration of $8{\pm}0.5g/L$ and thereafter they increased steeply.

• 약학회지
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• 제58권3호
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• pp.171-180
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• 2014

To enhance the in vitro permeation of lovastatin through excised hairless mouse and human cadaver skins, solubility was determined in various hydrophilic and lipophilic vehicles, and the effects of vehicles and penetration enhancers on the skin permeation from solution formulations were investigated. Solubility of lovastatin was highest in N-methyl-2-pyrrolidone (NMP) ($278.2{\pm}10.1$ mg/ml) and dimethyl sulfoxide (DMSO) ($162.2{\pm}9.7$ mg/ml). Among different pure vehicles used, NMP, DMSO, propylene glycol and isopropyl myristate provided some drug permeation ($6.9{\pm}1.1$, $5.9{\pm}1.6$, $3.0{\pm}0.5$ and $2.2{\pm}0.3{\mu}g/cm^2$ at 24 hr, respectively) through hairless mouse skin. The addition of oleic acid, linoleic acid and oleyl alcohol to DMSO showed the maximum permeation at around 5 v/v%, however, capric acid and caprylic acid had no enhancing effect. The increase of enhancer concentrations showed bell-shaped permeation rate, suggesting the presence of optimal concentration in lovastatin penetration. Increasing donor concentration from 10 mg/ml to 80 mg/ml in DMSO and a cosolvent of DMSO, NMP and DGME (3 : 3 : 4 v/v) did not show significant dose dependent permeation in both hairless mouse and human cadaver skins. The maximum lovastatin flux through human cadaver skin was found to be $0.87{\pm}0.46{\mu}g/cm^2$/hr with 5 v/v% linoleic acid and donor dose of 4 mg/0.64 $cm^2$ in the cosolvent. These results suggest that transdermal delivery of lovastatin would be feasible by establishing the optimal concentrations of donor dose and unsaturated fatty acids in appropriate vehicles.

• 대한안전경영과학회지
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• 제15권4호
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• pp.123-129
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• 2013

Among various manual materials handling tasks, pushing/pulling was known to be one of the risk factors for the low back and shoulder musculoskeletal disorders (MSDs). This study was conducted to find out an optimal solution set of the handle height and distance for 4-wheel cart with two vertical handles. Ten male college students participated in the pushing force measurement experiment. The face-centered cube design, one of the central composite designs, was applied for the experiment, and the isometric voluntary pushing force was measured in 9 treatment conditions. The second order response surface model was predicted by using the pushing strength as a response variable, and the handle height and distance as independent factors. According to the 2nd order response model, the handle height and distance showed nonlinear relationship with the isometric pushing strength. To maximize the 2nd order response model (pushing force), the handle height and distance were optimized. The optimal handle height was 'xyphoid process height - stature', and the optimal handle distance was '$1.25{\times}shoulder$ width'. When calculated using the anthropometric data of the subjects of this study, the optimal handle height was $115.4{\pm}3.4$ cm, slightly higher than the elbow height, and the handle distance was $52.9{\pm}2.3$ cm.