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      • KCI등재

        국가디지탈도서관 구축계획에 관한 연구

        한상완,김성혁,문성빈,이란주 한국문헌정보학회 1996 한국문헌정보학회지 Vol.30 No.1

        21세기 국가 정보력 제고를 위해서 세계 선진국가들은 국가디지털도서관 구축을 위한 전략과 막대한 예산을 투입하고 있다. 우리나라도 국가디지털도서관을 시급히 구축하여 다양한 멀티미디어 정보를 국민에게 제공할 수 있어야만 국가발전경쟁에서 선진국과 어깨를 나란히 할 수 있다. 따라서 이 연구에서는 우리나라의 국가디지털도서관 구축 방안을 마련하기 위해 우선 선진 외국의 디지털도서관의 구축사례를 연구한 다음 이를 바탕으로 우리나라 국가디지털도서관의 건축, 시설, 장비, 조직과 인력, 각종 사업과 기능 등을 소요예산과 함께 가능한한 구체적으로 연구 제시하였다 Many of the development countries in the world have been investing a lot of money and developing plans for a national digital library in order to secure the information power in the 21st century. In order for our country to compete with others, it is also urgent to build a National Digital Library in Korea, which can provide a variety of multimedia information for the people. In this study, based on the investigation of the several cases of the national digital libraries in the developed countries, we suggest a detailed plan for the National Digital Library which includes building, facilities, equipments, organization, staff, events, functions, and expected budget

      • 화상처리에 의한 춉트 스트랜드 섬유배향의 분포측정

        김혁,윤성운,한길영,심재기,이동기 조선대학교 생산기술연구소 1995 生産技術硏究 Vol.17 No.2

        In order to examine the accuracy of intensity method, the fiber orientation distribution of chopped strand reinforced polymeric composites is measured using image processing. Theoretical and experimental results of fiber orientation function are compared with each other for the composites having different fiber content and fiber orientations. An intensity method is used for the experimental investigation and the measured fiber orientation function is compared to the calculated one. The results show that, firstly, the feature of fiber orientation can be represented and identified by the fiber orientation function J measured and theoretical fiber orientation functions, J_(M) and J, respectively and related as J_(M)=0.73J. Secondly, as far as the measuring of fiber orientation is concerned, the intensity method is, in general, found to be quite effective due to its feature of using the intensity difference in the measuring ranges. Finally, the accuracy of the method increases when the fiber with less clash is considered.

      • PEG 분해균주의 분리와 PEG film의 상용성에 관한 연구

        이제혁,정성제,이준열,전억한 경희대학교 부설 식량자원개발연구소 1993 硏究論文集 Vol.14 No.-

        PEG를 sole carbon과 energy source로서 이용하는 미생물을 자연계에서 분리하였고, PEG의 분자량이 높아질수록 그 분해 미생물의 수가 감소하는 것을 확인하였다. 또한, liquid culture로서 PEG농도를 감소시키는 미생물을 선별하였고, 분해율은 PEG 8000이 약 18.8%였으며 PEG 10000은 약 25.4%인 것으로 조사되었다. PEG film의 제조를 위해 EMAA 및 EAA와의 상용성을 적외선 분광(IR) 스펙트럼을 사용하여 조사한 결과, EMAA와 EAA의 카르보닐기와 PEG의 에테르기와의 강한 수소결합이 형성으로 blend film제조시 상용성이 있는 것으로 확인되었다. Several strains capable of degrading PEGs(Polyethylene Glycols)were isolated and investigated for their biodgradation ability of PEGs. Microorganisms screened for the biodegradation studies were those grown on the PEG used as a sole carbon and energy source. It was known that the number of microorganisms decreased when grown on the high molecular weight of PEG(e.g. 20,000). A liquid culture was carried out with such microorgaisms and resulted in the decrease in PEG concentration meaning that PEG was degraded in the reactor. The biodegradability was found to be about 18.8% for PEG-8000 and 25.4% for PEG-10000, respectively. For the manufacture of biodegradable PEG film, EMAA/PEG and EAA/PEG blending ability was investigated with IR spectrum and showed that it was possible to produce blending film.

      • WDM-PON Link에서 upstream, transmission 성능 향상에 대한 연구

        권혁춘,정구익,하상진,한상국 연세대학교 전파통신연구소 2001 電波通信論文誌 Vol.5 No.1

        본 논문에서는 파장 분할 WDM-PON 구조를 제안하였으며, CW source를 가지고 Fabry-Perot laser에 injection 시키는 방법을 사용하여 4 channel 155Mbps를 20km upstream 전송하여 분석해 보았다. 제안된 WDM-PON 시스템에서의 이 injection locking 방법은 약 -7dBm ∼ -4dBm 정도의 높은 출력 파워를 제공하였고, 155Mbps 전송시 BER=10-9에서 receiver sensitivity 는 -38dBm정도를 유지하였다. 또한 제안된 구조에서 CW source로 파장 분할된 LED와 FP laser를 사용하여 각각에 대한 시스템에서의 성능을 비교 분석해 보았다. In this paper, we propose a spectrally sliced WDM-PON architecture and analyze the upstream transmission of 4 channels 155Mbps signals by 25km using an injection locking method of Fabry-Perot laser as a CW source. For a proposed WDM-PON system, This injection locking method provides high output power of -7dBm ∼ -4dBm and satisfies receiver sensitivity -38dBm for 10-9 Bit Error Rate for 155Mbps transmission. Also, we compare performances using spectrum-sliced LED and FP laser respectively as CW source for a proposed WDM-FON system.

      • KCI등재
      • DC/DC 승압 컨버터의 출력 특성 개선을 위한 스너버 회로 설계

        김성종,김인혁,정구종,손영익,한병문 明知大學校 産業技術硏究所 2009 産業技術硏究所論文集 Vol.28 No.-

        Applications of DC!DC boost converters are increasing recently in many industrial areas including renewable energy sources. High switching frequency of the power semiconductor devices including MOSFET, IGBT causes the EMI noise owing to the large values of dv/dt and di/dt. Since the EMI noises degrade power efficiency and reliability of the system many researches have been made to reduce the noise. This paper presents a passive snubber circuit to improve the tum-on and turn-off transients of the pulsewidth modulated (PWM) DC/DC boost converters. The noises in the output voltage of the DC!DC converter are reduced by adding a resistor and an inductor to the circuit. Experimental results show the effectiveness of the proposed snubber circuit to improve the output characteristics of the boost converter.

      • KCI등재후보

        국내 살모넬라 분리주에서 spvR 유전자 분포와 단일 뉴클레오티드 다형 연구

        권혁준,박경윤,박주연,박용호,김선중,유한상 대한감염학회 2004 감염과 화학요법 Vol.36 No.6

        목적 : 지금까지 병원성 살모넬라를 확인하기 위해 분자량이 큰 플라스미드의 존재 유무를 확인하여 왔으나 살모넬라 혈청형 및 검출 방법에 따라 양성율에 큰 차이를 보이고 있고, 일부 병원성 살모넬라 분리주에서 병원성 플라스미드가 관찰되지 않아 spv 유전자들의 유무에 대한 아른 확인방법이 필요하다. 본 실험은 국내 동물 유래 주요 살모넬라 혈청형에서 spvR 유전자의 분포를 알아보고, 병원성 살모넬라 분자진단을 위한 분자표지로써의 가치를 평가하기 위해 실행하였다. 재료 및 방법 : 국내 가축 유래 S. lyphimurium (ST, 26주), S. enteritidis (SE, 10주), S. pullorum (SP, 40주), S. gallinarum (SG, 53주)에 대해 GenBank에 등록된 ST, SE, SP의 spvR 유전자를 비교하여 ST와 SE 간에 차이를 보이는 single nucleotide polymorphism (SNP, 625번 뉴클레오티드)을 포함하도록 시발자를 합성하여 집락-PCR을 수행하였다. 증폭 산물(194bp)은 자동 염기서열장치를 이용하여 염기서열을 결정하였고, 제한효소인 MseI을 사용하여 PCR-RFLP를 실시하였다. 결과 : 집락-중합효소연쇄반응 결과 SP, SG, SE의 모든 (100%) 분리주에서 특이 증폭산물이 검출되었으나 ST의 경우 19주(73%)에서만 증폭되었다. 특히 병원성 관련 플라스미드가 관찰되지 않았던 SP 4주에서 특이적인 증폭산물이 검출되었다. 염기서열 분석결과 SE, SG, SP는 625번 뉴클레오티드에 아데닌을, ST는 구아닌을 가지고 있어 PCR-RFLP를 이용하여 쉽게 구분할 수 있었다. 결 론 : spvR에 대한 집락-중합효소연쇄 반응법은 병원성 플라스미드 검출법보다 SE, SP, SG 병원성 주를 신속하게 검출하는데 유용하고, 625번 뉴클레오티드의 SNP는 ST와 SE, SG, SP를 구분하는 분자표지로 사용될 수 있을 것으로 기대되며, ST에 비해 SE는 진화적으로 SG와 SP에 가까운 것으로 생각되었다. Background : The Salmonella virulence plasmid (spv) genes (spvR, A, B, C and D) on the large virulence plasmids of pathogenic Salmonella serotypes can replace the virulence of the whole plasmid. Recently, virulence plasmid-negative pathogenic Salmonella isolates were isolated. However, positive rates of spv genes among Korean Salmonella serotypes have been obscure. spv genes are conserved in compared to other virulence genes but there are single nucleotide polymorphisms (SNPs) conserved in only certain serotype. Such SNPs are useful for differentiation and understanding evolution of certain serotypes. Materials and Methods : Salmonella serotypes isolated from live stocks [Salmonella typhimurium (ST, 26), S. enteritidis (SE, 10), S. gallinarum (SG, 40) and S. pullorum (SP, 53)] were used for colony-PCR. A primer set covering single nucleotide polymorphism (SNP) at 625th nucleotide of spvR was designed. The nucleotide sequences of amplicons were determined by cyclic sequencing method and RFLP was performed by using MseI. Results : All isolates of SE, SG and SP, including four plasmid-negative isolates, showed specific amplicons but not all of ST (19/26, 73%) were positive to spvR. Based on the nucleotide sequence of 625th nucleotide and PCR-RFLP, SE, SG and SP [A(625)] and ST [G(625)] could be differentiated. Conclusion : spvR can be used as a molecular marker to detect virulent SE, SG, SP and the SNP may be useful for differentiation of SE, SG, SP and ST. According to the SNP study SE may be evolutionarily closer to SG and SP than ST.

      • 기관골 신생증 1예

        오영상,이은우,정종혁,문승원,김수현,김동한,양혁승,박정환,박경옥,강성수,이영직 朝鮮大學校 附設 醫學硏究所 2006 The Medical Journal of Chosun University Vol.31 No.2

        Tracheobronchopathia osteoplastica is a rare disorder of unknown cause characterized by the projection of numerous bony or cartilaginous submucosal nodules into the tracheobronchial lumen with sparing of the posterior membranous portion of tracheobronchial tree. In the past, most of the cases were diagnosed as secondary finding at autopsy. Nowaday, the key component of the evaluation is flexible fiberoptic laryngoscopy and bronchoscopy, which typically demonstrates irregular spicules of subrnucosal bone and cartilage projecting into the tracheobronchial lumen and causing various degrees of airway obstruction. A 45 years old man was visited Sunchon St. Carollo hospital due to discomfort on throat. We saw several nodules just below vocal cord via laryngoscope. The computed tomography revealed multiple small calcified nqdules on trachea and both main bronchi. Pathologic finding of bronchoscopic biopsy showed abnormal proliferation of bony and cartilagious nodules in the tracheal submucosa. These fingdings were consistent with tracheobronchopathia osteoplastica. We report here on a case of tracheobronchopathia osteoplastica with review of literature.

      • SCOPUSSCIEKCI등재

        사람 뇌척수액중 Transthyretin의 항산화작용

        양성렬,최기오,박종근,류문희,홍석노,김수한,안봉환,이제혁,이민화 대한신경외과학회 1994 Journal of Korean neurosurgical society Vol.23 No.4

        Protective effects of human cerebrospinal fluid antioxidants against enzyme inactivation caused by metal-catalyzed oxidation systems were investigated. When purified glutamine synthetase(GS) was incubated with human cerebrospinal fluid(CSF), the enzyme was progressively inactivated. Catalase and EDTA could inhibit the enzyme inactivation by 50-80%. Small-molecular(Mr< -10,000) fraction of CSF inactivated the exogenous GS, but large-molecular(Mr> -10,000) fraction did not. The GS inactivation by the small-molecular fraction was also markedly inhibited by catalase and EDTA. These results suggested that metal-catalyzed oxidation is involved in the GS inactivation by the small-molecular fraction of CSF. Dithiothreitol(DTT) was shown to inhibit almost completely the oxidative inactivation of GS by CSF. However, DTT inhibited only partially the oxidative inactivation of GS caused by small-molecular fraction of CSF. When large-molecular fraction of CSF was separated by anion-exchange HPLC chromatogrpahy, there was a peak of antioxidant activity inhibiting the small-molecular fraction-induced GS inactivation in the presence of DTT. The antioxidant activity was neutralized by monoclonal antibodies to transthyretin. Purified transthyretin was found to efficiently inhibit ascorbate/Cu^(2+)-induced GS inactivation in the presence of DTT. Uric acid and glucose did not show any protective effect on the GS inactivation in the same condition. The above results suggest that metal-catalyzed oxidation occurs normally in human CSF, and that transthyretin may play an important role as a CSF antioxidant in protecting proteins from metal-catalyzed oxidation.

      • KCI등재

        일반 교육-특수교육 완전 통합을 위한 기초 연구 : 탐구조사 An Exploratory Study

        권상혁,황윤한 국립특수교육원 1995 특수교육연구 Vol.2 No.-

        Total integration is the most ethical and humanistic way of teaching exceptional children. The purpose of this study were 1) to examine the problems in special education, 2) to investigate the reasons for being unable to integrate exceptional children with their non-handicapped peers, and 3) to obtain suggestions to accentuate total integration recommended by special education teachers. Thirty-seven elementary school special education teachers participated in this study. Problems in special education practice pointed by special education teachers vary from the lack of perceptions of educational leaders, teachers, students, and students to the education of quality special education teachers. Reasons for being unable to integrate exceptional children with their non-handicapped peers were also related to the problems in current special education culture. Special education teachers suggested various ways to accentuate total integration.

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