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.

인터리버를 이용한 eHDR-WPAN 시스템의 성능 분석

정승희,이현재,오창헌 한국기술교육대학교 2006 論文集 Vol.12 No.1

In this paper, we propose a performance of improvement method for eHDR-WPAN system with Interleaver. The pattern of burst error caused by fading in indoor wireless channel. For the reason, using of Interleaver(make burst error to random error) can be enhanced to error-rate in eHDR-WPAN system. Interleaver at the simulation considered Convolutional, Block and Random, respectively. Available symbol spacing of Interleaver is assumed 9 and 27. In results, Block-Interleaver is shown that a performance of improvement about 0.6dB of E_(b)/N_(o) at 10^(-4). Therefore, the suitable Interleaver for eHDR-WPAN system was 9 symbol spacing of Block Interleaver.

交通事故의 豫防對策에 대하여

서승록,신승헌 대구대학교 산업기술연구소 1984 産業技術硏究 Vol.3 No.-

This paper was analnzed the 1,622 traffic accidents of kyounbuk area provided by the police bureau in 1982 and showed the precautionary measures of traffic accidents by using data sheets. This research suggestds as follows: 1. Strengthening of traffic rules and educations. 2. Investigation of accident patterns. 3. Improvement of driver's labour conditions. 4. Installation of safety devices. 5. Study of human engineering of traffic indicators. 6. Improvement of driving test

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.

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).

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.

시효처리와 마모체가 치과용 콤포짓트 레진의 마모에 주는 영향

김승헌,임범순,문현정,이용근,김철위 大韓齒科器材學會 2001 대한치과재료학회지 Vol.28 No.4

Over the last decade, the use of posterior resin composites has grown considerably. Wear resistance of restorative materials is important for clinical longevity, esthetics, and resistance to dental plaque. The purpose of this study was to evaluate the effect of artificial saliva and 75% ethanol solution on the wear resistance of composite resins by measuring the amounts of wear, and compare the effect of antagonistic materials on the wear resistance of composite resins. Four universal composite resins (Z100, Aelitefil, Spectrum, and Unifill F) and two condensable composite resins (Surefil and Synergy Compact) were measured. Cylinder type specimens were light-cured for 40 sec on the wear surface, and 20 sec on each side surface. The surface for wear testing was polished by 600 grit SiC paper. Three different antagonistic materials (600 grit SiC paper, amalgam, and procelain) were used as an antagonist for 2-body wear test. After speciments were aged in 37℃, artificial saliva and 75% ethanol solution for specific periods (1 day, 1 month and 2 month), 2-body wear testing was performed by the FRP-2000 friction tester with applying 500 g load (80 kPa) to the specimen. The wear test was performed for 10 min and 30㎖ distilled water was used as lubricant. Amount of wear was measured by microscopic measuring device of Micro Hardness Tester in 0.1㎛ scale. There was significant difference in wear resistance of composite resins (p<0.05). Composite resins with filler content below 59 vol.% showed higher wear resistance that composite resins those with filler content above 62 vol.%. In composite resins from 1 day to 1 months (p<0.05). On the contray, the wear amounts of groups which filler fraction were above 62 vol.% did not show any significant differences with increasing aging period (p>0.05). In 1 day aged groups, the wear amounts of the groups aged in 75% ethanol solution were more than those of the groups aged for 1 month (p=0.045) and Spectrum group aged for 2 month (p=0.006). Amounts of wear were significantly decreased with changing antagonist from 600 grit SiC paper to amalgam or porcelain (p<0.05).

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.

4개 간척 지구에 분포하는 식생과 토양 염류농도

이승헌,지광재,안열,노희명 한국환경농학회 2003 한국환경농학회지 Vol.22 No.2

토양 제염이 토양 화학성 변화와 식물 분포에 미치는 영향을 분석하여 간척농경지의 효율적인 관리방안에 대한 기초자료를 확보하고자 본 연구를 실시하였다. 방조제 체절전후 자연식생이 존재하는 9개 지점에서 식생분포 특징을 조사하고 2개 지점에 대해서는 토양과 식생가의 관계를 검토하였다. 9개 조사지점에서 11목, 14과, 46속, 49종, 8변종, 1품종등 총 58종류의 식생분포가 관찰되었고 자연상태를 잘 유지한 대호 식생보전구와 석문 국가공단 예정 부지에서의 출현종수가 다양하게 분포하였으며 해수를 유통시키고 있는 홍보지구나 만경강, 동진강 하구의 식생은 10 정도로 단순하였다. 9개 조사지점에서 가장 빈도가 높게 출현한 종은 벼과, 명아주과, 국화과에 속하는 나문재(Suaeda asparagoides (Miq.) Maakino), 객개미취(Aster tripolium L.), 갈대(Phragmites australis Trin.), 해홍나물(Suaeda maritima Dum.), 칠면초(Suaeda japonica Dum.), 천일사초(Carex scabrifolia Steud.) 토양에서 염류(Saline)토양으로 그리고 최종적으로 일반 토양으로 변화하였다. 명아주과의 식생은 염도(ECe)가 30 dS/m 전후인 토양에서 출현하여 10 dS/m까지 지속되고, 20dS/m전후에서 객개미취, 산조풀, 사데풀 등이 출현하였으며 10 dS/m 이하에서는 일반육상에서 볼 수 있는 식생종들이 출현하였다. 그러나 토양제염과 동시에 식생의 천이가 일어나는 것은 아니며, 외부에서 종자 등의 식물이 유입될 확률이 있어야하므로, 초기간척지의 식생을 조기에 정착하기 위해서는 토양검정을 통해 적정 염도에서 정착할 수 있는 식생의 인공식재 내지 종자 산파를 통해 촉진시키는 것이 효과적일 것으로 판단된다. This research was conducted to present reference data to be used as newly reclaimed tidal land management. We investigated vegetation succession at 4 reclaimed/reclaiming project areas and discussed relationship with soil and vegetation through investigation and analysis soil chemical characteristics at 2 areas. 14 families 58 kinds were investigated. Vegetation were various at Dea-Ho conservation plot and Seok-Mun National Industrial Area which are maintaining naturally. Vegetation were simple at Hong-Bo and Dongjin and ManKyong river areas which effected sea water. Common species that were investigated at 9 sites were Suaeda asparagoides, Aster tripolium, Phragmites australis, Suaeda maritima, Suaeda japonica, Carex scabrifolia. As soil desalinization progressing, soil classified at first saline-sodic soil, the next saline soil and then normal soil. Chenopodiaceae revealed at about 30 dS/m of soil W e and existed to 10 dS/m of soil ECe. At about 20 dS/m of soil ECe, Aster tripolium, Chlamagotis epigeios, and Sonchus brachyotus revealed and then non halophytes and commom plants at inland revealed at low soil ECe of about 10 dS/m However it was not to progress vegetation succession and soil desalinization at the same time, owing to input of seeds or plants etc from out-ecosystern So for promotion of vegetation at newly reclaimed tidal land, we proposed that it was very effective to plant artificially halophytes or suitable species through soil test.