• Macromolecular Research
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• 제14권6호
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• pp.596-602
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• 2006

The effect of high-temperature spinning and poly(vinyl pyrrolidone) (PVP) additive on poly(vinylidene fluoride) (PVDF) hollow fiber membranes was investigated using differential scanning calorimetry, X-ray diffraction measurement, and scanning electron microscopy, together with the corresponding microfiltration performances such as water flux, rejection rate, and elongational strength. Using high-temperature spinning, porous hollow fiber membranes with particulate morphology were prepared through PVDF crystallization. The particulate structure of the membranes was further modified by the addition of miscible PVP with PVDF. Due to these effects, the rejection rate and strength of the fibers were increased at the expense of reduced water flux and mean pore size, which indicates that high-temperature spinning and PVP addition are vary effective to control the morphology of PVDF hollow fiber membranes for microfiltration.

• 한국물환경학회지
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• 제28권5호
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• pp.657-662
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• 2012

This study was carried out to evaluate the removal rate of organic and inorganic matters from landfill leachate using pre-treatment process as coagulation and limonite adsorption, and membrane process as RO (reverse osmosis) and NF(nanofiltration). By adding limonite adsorption as pre-treatment process, about 40% of organic matters in leachate was removed through pre-treatment process and 74.7% of boron was removed after RO process without pH adjustment. The rejection rate of boron in RO process mainly depends on the pH and increased at pH value of 10. RO process was performed as two stage system adjusting pH condtion to 7 and 10 in second RO stage for boron removal. Most (>90%) of TOC, Cl- and inorganic matters as Ca was rejected in first RO stage, the residue was rejected in second RO and the rejection rate was above 97%. Considering economic efficiency of operation cost, NF substituted for the first RO and total removal rate of TOC was above 90%. Through RO system toxicity to Daphnia in leachate was removed completely.

• 한국주조공학회지
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• 제31권1호
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• pp.7-10
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• 2011

• 디지털융복합연구
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• 제10권8호
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• pp.173-178
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• 2012

어휘 인식을 위한 모델 생성에서 준비하지 않은 트라이폰이 생성된다. 이는 모델 파라미터의 초기 추정치를 생성하지 못하는 원인으로 어휘 모델을 구성할 수 없는 단점으로 나타난다. 결과적으로 가우시안 모델의 정교함이 떨어지게 되어 인식률을 저하시키게 된다. 이를 개선하기 위한 방법으로 미등록 어휘 거절 알고리즘을 이용한 오류 보정 시스템을 제안한다. 이 방법은 어휘 인식 모델 생성 시 등록되지 않은 어휘를 거절하여 인식률을 향상시킨다. 또한 확률 분포를 이용하여 어휘 분석과 의미를 파악하고 음운 변동이 적용되기 전의 문자열로 복원시킨다. 시스템 분석은 음소 유사율과 신뢰도를 이용하여 오류 보정율을 확인하였고 성능 평가를 위해 에러 패턴, 오류 패턴, 의미 패턴 방법을 이용하여 평가하였다. 성능 평가 결과 2.8%의 오류 보정률의 향상을 보였다.

• Membrane and Water Treatment
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• 제11권4호
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• pp.303-312
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• 2020

This study aims to investigate at a laboratory scale fluorides removal from an industrial wastewater having excessive F^- concentration through a hybrid process combining neutralization and membrane separation. For the membrane separation operation, both Reverse Osmosis (RO) and Nanofiltration (NF) were investigated and confronted. The optimized neutralization step with hydrated lime allowed reaching fluoride removal rates of 99.1± 0.4 %. To simulate continuous process, consecutive batch treatments with full recirculation of membrane process brines were conducted. Despite the relatively high super saturations with respect to CaF₂, no membrane cloaking was observed. The RO polishing treatment allowed decreasing the permeate fluoride concentration to 0.9± 0.3 mg/L with a fluoride rejection rate of 93± 2% at the optimal transmembrane pressure of around 100 psi. When NF membrane was used to treat neutralization filtrate, the permeate fluoride concentration dropped to 1.1± 0.4 mg/L with a fluoride rejection rate of 88± 5% at the optimal pressure of around 80 psi. Thus, with respect to RO, NF allowed roughly 20% decrease of the driving pressure at the expense of only 5% drop of rejection rate. Both NF and RO permeates at optimal operating transmembrane pressures respect environmental regulations for reject streams discharge into the environment.

• 한국임상약학회지
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• 제12권1호
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• pp.13-21
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• 2002

After the introduction of cyclosporin, the graft survival rate of renal transplant and patients' life expectancy have been greatly improved. However, cyclosporin is known to cause several undesirable side effects, one of which is hyperuricemia, which may subsequently cause gouty nephropathy and graft dysfunction. The purpose of this study was to evaluate the frequency and predisposing factors of hyperuricemia in cyclosporin-treated patients within one year of kidney transplantation and uricosuric efficacy of benzbromarone. The patients who were treated with cyclosporin after kidney transplantation in 1998 and the patients who were treated with benzbromarone for the control of cyclosporin-induced hyperuricemia in 1999 were investigated retrospectively. Among the 76 patients in cyclosporin-treated patients in 1998, hyperuricemia occurred in 55 patients $(72.4\%)$ and the mean time from kidney transplantation to occurrence of hyperuicemia was $5.0\pm8.0$ months. In 1999, 22 patients were treated with benzbromarone for hyperuricemia and their mean time from kidney transplantation to occurrence of hyperuricemia was $4.5\pm10.4$ months. Acute rejection developed in one patient $(4.8\%)$ out of 21 normo-uricemic patients and 11 patients $(20.0\%)$ out of 55 hyperuricemic patients in 1998. The difference of rejection rate in these two groups was significant (p<0.001). There was no difference of rejection rate between before and after treatment of benzbromarone. Cyclosporin trough levels did not show a significant correlation with the serum uric acid levels among the three groups. However, hyperuricemic patients showed significantly higher serum creatinine levels than patients with normal uric acid levels (p<0.001). Benzbromarone decreased serum uric acid levels from $8.3\pm2.3\;mg/dl\;to\;5.1\pm2.0\;mg/dl$ (p<0.0001) and normalizing serum uric acid in all of 22 patients. Except for one patient $(4.5\%)$ who experienced diarrhea, no significant side effect was noted.

• 대한음성학회지:말소리
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• 제43호
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• pp.45-55
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• 2002

High reliability of automatic speaker recognition regardless of voice conditions is necessary for forensic application. Audio recordings in real cases are not consistent in voice conditions, such as duration, time interval of recording, given text or conversational speech, transmission channel, etc. In this study the variation of verification error rate of ASR system with the voice conditions was investigated. As a result in order to decrease both false rejection rate and false acception rate, the various voices should be used for training and the duration of train voices should be longer than the test voices.

• 한국정보처리학회논문지
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• 제3권4호
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• pp.915-925
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• 1996

본 논문에서는 오프라인 필기체 숫자의 변형을 흡수할 수 있는 효과적인 특징을 찾기 위해서 여러 가지 특징의 성능을 비교하였다. 실험적인 성능 비교 결과는 윤곽 선을 이용한 4방향성 특징 그리고 교차 거리＋교차＋망＋투영 특징이 오프라인 필기체 숫자 인식에서 인식률과 인식 시간측면에서 효과적인 것으로 나타났다. 그리고 단일 신경회로망에서 인식률의 한계점을 극복하기 위하여 효과적인 특징을 조합한 복합특징 으로 다수결투표와 신뢰도 지수를 이용한 모듈화된 신경회로망을 제안한다. 제안된 방식의 성능을 검증하기 위해서 캐나다의 Concordia 대학교와 한국의 Dong-A 대학교 오프라인 필기체 숫자 데이터베이스에 대하여 실험을 하였다. Concordia 대학교의 데이터 베이스는 97.1%의 정인식률, 1.5%의 기각률, 1.4%의 오인식률 그리고 98.5%의 신뢰도가 나타났으며, Dong-A 대학 교의 데이터 베이스는 98%의 정인식률, 1.2%의 기각률, 0.8%의 오인식률 그리고 99.1%의 신뢰도가 나타났다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권3호
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• pp.271-276
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• 2004

This paper is a research on the dynamic signature verification of error rate which are false rejection rate and false acceptance rate, the size of signature verification engine, the size of the characteristic vectors of a signature, the ability to distinguish similar signatures, the processing speed and so on. Also, we present our efficient user interface and performance results.

• 멤브레인
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• 제5권4호
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• pp.137-144
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• 1995

Hydranautic사의 셀룰로오즈 아세테이트 재질로 된 RO S/W 4040을 이용하여 2성분계의 붕산수용액 및 붕산수에 함유된 실리카의 3성분계 수용액에 대하여 조업온도, 운전압력 및 공급유량 변화가 투과량, 붕산회수율, 실리카 배제율에 미치는 영향에 대한 실험을 수행하였다. 붕산수용액의 경우 35$^{\circ}$C, 20atm 및 원액의 유속이 2.82l/min에서 붕산회수율 및 투과도는 각각 58.7% 및 2.82l/min, 35$^{\circ}$C, 10atm에서는 68.1% 및 1.56l/min이었다. 또한 실리카 및 붕산이 함께 함유된 용액의 경우 35$^{\circ}$C, 3.2atm에서 붕산회수율 69.7%, 실리카 배제율 97.5% 및 투과도 0.47l/min의 결과를 보여주었으며, 35$^{\circ}$C, 20atm에서 원액의 유속이 2.92l/min의 경우 붕산회수율 56.4%, 실리카 배제율 96.1% 및 투과도 2.72l/min의 결과를 보여 주었다.