CAN 프로토콜 성능 해석에 관한 연구

홍승호,김욱헌 漢陽大學校 工學技術硏究所 1998 工學技術論文集 Vol.7 No.1

CAN에 접속된 각종 필드 장비들로부터 생성되는 데이터는 크게 산발적 실시간, 주기적 실시간 및 비실시간 데이터의 세 가지 종류로 구분된다. 특성이 다른 이러한 데이터들의 트래픽이 하나의 네트워크 미디엄을 공유하는 경우에 네트워크 트래픽이 적절히 관리되지 못하면 CAN 버스에 접속되는 응용시스템의 성능에 악영향을 미칠 수 있다. 본 연구는 CAN을 자동화 시스템에 도입하는 경우에 실시간 데이터가 전송 허용 한계치를 넘지 않는 동시에 CAN 대역폭을 충분히 활용하도록 하는 대역폭 할당 기법을 제시한다. 본 연구에서는 또한 CAN의 이산 사건 시스템 모델과 제어 시스템의 연속 시간 모델을 통합한 통합 시뮬레이션 모델을 개발한다. 시뮬레이션 모델을 통하여 본 논문에서 제시하는 대역폭 할당 알고리듬의 타당성을 검증하고 실시간 데이터의 지연 시간이 실시간으로 동작되는 제어 시스템의 성능에 미치는 영향을 분석한다. Messages generated from field devices connected by CAN bus are classified into three categories : (1) real-time aperiodic messages, (2) real-time periodic messages, (3) non-real-time messages. Because these share one CAN bus medium, if the traffic of these messages are not efficiently managed, the performance of the application systems interconnected into the CAN bus can be degraded. This paper proposes a bandwidth allocation scheme that satisfies the performance requirement of application systems as well as fully utilizes the bandwidth of CAN bus. Using the simulation model of CAN bus, this study validates the bandwidth allocation scheme and analyzes the effect of network-induced delay on the performance of control system.

오염기름 제염에 있어 초임계 이산화탄소의 사용 타당성 연구

박승현,박광헌 慶熙大學校 材料科學技術硏究所 1998 材料科學技術硏究論集 Vol.11 No.-

The main object of this study is a possible use of supercritical fluid in decontamination of contaminated mechanical parts and dresses used in nuclear power plants. Supercritical CO_(2) is a good solvent for cleaning these materials, since it has a powerful ability of penetration to unreachable places and high solubility of oils. And the solubility changes dramatically according to the pressure change, so contaminants can be collected without making any secondary waste. In this study, solubility and removal efficiency of pure oil, gear oil, and grease were measured using supercritical CO_(2) dry cleaning method. The solubility of several oils was shown to increase with pressure ranging from 80 to 200 bars. The removal efficiencies of oil in cleaning mothods using water and that using perclorethylene were compared to dry cleaning with supercritical CO_(2). Oils were removed over 99% in supercritical CO_(2) and in percloroethylene ; however, most of oil was remained in the case of water washing at 60℃. In nuclear power plants, main components of radioactive wastes to be removed are Cs and I. Cs and I were completely removed when we used the water washing method, while percloroethylene and supercritical dry cleaning method couldn't remove Cs and I. To eliminate these components, we used modifier, i.e., a mixture of ethanol and pure water. The results show that removal efficiency of Cs and I in supercritical CO_(2) greatly increases with addition of ethanol and pure water. If this technique becomes materialized, there will be no or less secondary waste for decontamination of contaminated parts and dresses, resulting in more environmentally clean nuclear power plants.

대호 간척기 토양의 염농도별 밭작물의 염해 평가

이승헌,류순호,설수일,안열,정영상,이상모 江原大學校 附設 環境硏究所 2001 環境硏究 Vol.18 No.-

This study was carried out to obtain the basic data for selecting the applicable crops in reclaimed land during desalinization period. A pot experiment was conducted with 5 different electrical conductivities of the saturated extracts (ECe 1, 3, 9, 14, and 16 dS·m^(-1)) of soils taken from the Dae-Ho reclaimed tidal lands. Eight crops (Chinese cabbage, radish, tomato, red pepper, buckwheat, soybean, sesame, and green perilla) were grown for 37days. Plant height and number of leaves were surveyed on 2 and 4 weeks after seeding, and on harvest time (5 weeks). After harvest, dry weights of harvested crops were measured and soil chemical properties were analyzed. Emergence rates of crops were comparatively high except sesame. For sesame, there was no emergence at ECe over 3 dS·m^(-1). Growth and dry weight decreased significantly as increasing ECe. The ECe which decreased 50% of dry weight index were 14.2 dS·m^(-1) for radish, 11.4 dS·m^(-1) for Chinese cabbage, 10.2 dS·m^(-1) for tomato for red pepper, 8.9 dS·m^(-1) for buckwheat and green perilla, 8.6 dS·m^(-1) for soybean, and 8.9 dS·m^(-1) for tomato. At higher ECe that start the growth inhibition, increasing 1 dS·m^(-1) in ECe, 7.7, 6.5, 5.9, 5.6, 5.2, and 4.9% of dry weight decreased for buckwheat, green perilla, Chinese cabbage, radish, soybean, and tomato (red pepper), respectively. The critical value of ECe for crop survival except sesame was 15.4~23.1 dS·m^(-1).

소독제 과산화수소에 노출된 Legionella pneumophila의 생존력

송승열,오계헌 순천향대학교 기초과학연구소 2000 순천향자연과학연구 논문집 Vol.6 No.2

Survival of L. pneumophila exposed by hydrogen peroxide as a disinfectant was monitored. Initially morphological and physiological characteristics were examined. The strain was small Gram-negative cocco-bacillus and could not degrade carbohydrate. Survival of L. pneumophila was examined in the buffered charcoal yeast extract medium containing 0-5% hydrogen peroxide. The survival rates of cells decreased with increasing concentrations of hydrogen peroxide. The growth of L. pneumophila was significantly inhibited by the exposure of hydrogen peroxide. When the strain was treated with >0.01% hydrogen peroxide, the cells could not grow on the medium. Survival rate of cells decreased when trated with >0.01% of concentrations of hydrogen peroxide. Time-survival studies showed that exposure of L. pneumophila cells to 0.3% hydrogen peroxide resulted in at least 80% killing after 90 min and not detected the survivors at 120 min. No cells were grown at the concentrations of 1%> hydrogen peroxide. As the result, hydrogen peroxide suggested a good candidate for the control agent of L. pneumophila.

Benzoate에서 배양된 Acinetobacter baumannii로부터 Catechol 1,2-dixoygenase의 정제와 촉매적 성질

송승열,오계헌 순천향대학교 기초과학연구소 2001 순천향자연과학연구 논문집 Vol.7 No.2

The purpose of this work was to perform the catalytic properties and sequence analysis of catechol 1,2-dioxygenase (C1,2O) purified from Acinetobacter baumannii which was grown on benzoate as a carbon source. C1,20 demonstrated its enzyme activity to other substrates, catechol and 4-methylcatechol. The optimum temperature of C1,20 was 35℃, and the optimal pH was in the range from pH 7.5 to 9. Ag^+, Hg^+, and Cu^+2 showed inhibitory effect on the activity of C1,20. Molecular weight of the enzyme was determined to approximately 36 kDa by SDS-PAGE. N-terminal amino acid sequence of C1,20 was analysed as ^1MNYQQIDALVKQMNVDTAKG^20 and exhibited 95% sequence homology with that of C1,20 from Acinetobacter radioresistens. For internal sequencing analysis, trypsin digestion and peptide mapping were performed. Molecular weights of three digested peptide fragments were analyzed as 966.3 dalton, 1933.8 dalton and 2081.7 dalton by MALDI-TOF, which were matched with internal sequences (^1SQSDFNLRR^9, ^1TIEGPLYVAGAPESVGFAR^19, ^1HGNRPSHVHYFVSAPGYR^18)of Acinetobacter radioresistens.

난관 소통성의 진단에 있어서 초음파 검사와 진단적 복강경 및 개복술의 비교

이승연,채규정,나미옥,이정헌,류철희,김종덕 대한산부인과초음파학회 2000 대한산부인과초음파학회지 Vol.2 No.2

청양 지역에 분포하는 트라이아스기 후기의 조계리층에서 산출된 규화목 화석

김종헌,백승덕,이원국 공주대학교 과학교육연구소 2003 과학교육연구 Vol.34 No.-

충남 청양 지역에 분포하는 트라이아스기 후기의 조계리층에서 규화목 화석이 발견되었다. 규화목 화석의 산출은 남한에 분포하는 하부중생계 지층에서 최초의 기록이다. 분류학적 연구결과, 구과류에 속하는 Xenoxylon sp.와 Dadoxylon sp.의 2속 2종이 식별되었다. 본 논문에서 구과류 화석의 특징과 비교 및 그 의미에 대해서 고찰하였다. Petrified wood fossils are discovered from the Upper Triassic Jogyeri Formation distributed in the Cheongyang area. The occurrence of petrified fossils is the first record in the Lower Mesozoic strata distributed in South Korea. As a result of anatomical study of wood fossils, two specie belonging to two genera of Xenoxylon sp. and Dadoxylon sp. which belong to conifers, are recognized. This paper deals with the characteristics, comparison and significance of conifer wood fossils.

노인정신의학 연구의 발전 방향 : 알쯔하이머병을 중심으로 Research on Alzheimer's Disease

김승현,이헌정 大韓神經精神醫學會 2002 신경정신의학 Vol.41 No.5

알쯔하이머병(AD)은 전반적인 인지기능의 저하를 보이는 진행성 치매이며, 병리학적으로는 amyloid plaque와 neurofibrillary tangle이 특징적이다. 최근 십여 년 동안 AD의 병태생리에 대한 연구에 있어 중요한 진전이 있었으며, 그로 인하여 질병 발생의 근원적 과정을 직접적으로 차단할 수 있는 새로운 치료적 시도들이 점차 가능해지고 있다. AD의 병인은 아직 확실하게 규명되지 않았지만 일반적으로 질병의 최종 공통경로로서 '아밀로이드 가설'이 가장 유력한 원인 가설로 인정받고 있다. AD를 치료하기 위한 새로운 전략들은 β-amyloid protein(Aβ)의 생산을 중단시키고, Aβ의 제거를 촉진하거나, Aβ의 응집과 침전을 방해하는 시도들이다. 저자들은 본고에서 AD에 대한 현재까지의 연구성과를 요약하고 최근 새롭게 주목받고 있는 치료적 접근 방법에 대해 간략하게 설명하려고 한다. Alzheimer's disease(AD) is a progressive dementia characterized by global cognitive decline and is defined pathologically by amyloid plaques and neurofibrillary tangles. In the past 10 years, important progress has been made in the understanding of the pathogenic mechanism of AD, and new therapeutic targets have become available that should allow the underlying disease process to be tackled directly. In this respect, the 'amyloid hypothesis' has been become the dominant theory in the cause of AD. New strategies for conquering the AD include attempts to stop the production of β-amyloid protein(Aβ), increasing Aβ clearance, or interfere with Aβ aggregation and precipitation into fibril or plaques. This review summarizes recent advances in research on AD and inspects the perspective of research in potential therapies of AD.

알코올의 수분함량과 몰비 변화에 따른 실리콘알콕사이드(TEOS·TMOS)의 수율

노재성,조헌영,홍성수,조태웅 忠南大學校 産業技術硏究所 1993 산업기술연구논문집 Vol.8 No.1

Silicon alkoxides(TEOS:tetraethylorthosilicate and TMOS:tetramethylorthosilicate) were synthesized from silicon tetrachloride and ethanol or methanol with the variation of the mole ratio (alcohol/SiCl_4) and the water contents in the alcohol. The optimum mole ratios of alcohol/SiCl_4 were measured to be betweem 4 and 5 and the reactions completed within one hour. The yield of TEOS decreased from 70% to 48% as the water contents increased from 0.1% to 1.0% in ethanol.

진화계획법(EP)을 이용한 산업체 열병합발전시스템의 일간 최적운전계획

류승헌,김규호 永同大學校 1998 硏究論叢 Vol.4 No.1

본 논문에서는 진화계획법(Evolutionary Programming, EP)을 이용하여 산업체 열병합발전시스템의 일간 최적운전계획을 수립하였다. 최적운전 대상 열병합발전시스템은 축열조와 전기저장장치를 포함하는 복잡한 시스템을 선택하였다. 일간 최적운전계획은 산업체의 열부하와 전기부하를 공급하는데 필요한 일간 총 에너지비용을 최소화하도록 수립하였다. 에너지비용 계산시 열병합발전시스템의 연료비 뿐만 아니라 산업체의 전기비용까지 고려하였다. 실계통 시뮬레이션을 통하여 복잡한 열병합 발전시스템의 일간 최적운전계획을 진화계획법을 이용하여 신속하게 수립할 수 있음을 입증하였고, 동적계획법에 의한 최적운전계획 결과와 비교함으로써 그 정확성을 검증하였다. This paper presents the establishment of an optimal daily operation scheduling for the industrial cogenertion system using EP(Evolutionary Programming). The industrial cogeneration system has both thermal storage tank and electrical storage facility. The minimum energy cost for thermal and electrical loads is calculated through optimal daily operation scheduling. The total energy cost includes both fuel costs and electrical rates imposed to the industry. Through the real system simulation, it is verified that the optimal operation scheduling can be established fastly and accurately by the use of EP.