인터넷 데이터베이스와 온라인 데이터베이스의 검색시스템 검색효율 비교

안태경,김현희 明知大學校 文獻情報學會 1999 文獻情報學論集 Vol.- No.6

인터넷은 상용데이터베이스에 없는 정보와 상용데이터베이스와 거의 같은 정보를 무료로 입수할 수 있는 경우도 있으며 새로운 정보원으로서 중요성을 더해가고 있다. 전문 검색사들은 어떤 때 무슨 온라인 정보원을 이용해야 하는지에 관한 안내가 필요하게 되었다. 따라서 본 연구에서는 먼저 인터넷 데이터베이스와 상용 데이터베이스의 특성을 기존 연구 결과들에서 살펴본 후 두 탐색의 검색 효율성을 측정하기 위해서 이용자에게 의뢰 받은 정보 질문들을 이용하여 실험을 한 후 두 시스템의 탐색 결과를 분석하여 검색소요시간, 최종검색 건수, 적합성 등을 비교해 보았다. 실험 결과, 검색소요시간은 4명의 정보검색사가 6개의 질문 모두를 검색하는데 소요된 시간은 인터넷 평균 14.67분, 상용온라인 평균 4.75분으로 인터넷은 상용온라인 보다 약 3배의 검색시간이 소요되었다. 또한 정보검색속도의 문제는 검색성능과도 관련이 있지만 비용의 문제가 제기 되었다. 적합성 측정에서는 검색자와 질문자 적합성을 측정하였는데 모두 유사한 평가를 하고 있었다. 데이터베이스의 유형별 정보검색의 적합성 측정은 인터넷 데이터베이스에는 수치데이터, 연구기관자료, 디렉토리형 정보원, 기업의 동향분석자료 등에 강한 것으로 나타났다. 상용온라인 데이터베이스는 학술지의 전문(full-text), 학술지의 서지데이터에서 우수한 것으로 적합성이 평가 되었다.

경량 고강도 Mg-Zn계합금의 조직과 내식성에 관한 연구

안효준,남태현,임수근,안인섭,허보영,김기원 慶尙大學校 1995 論文集 Vol.34 No.1

The purpose in this study is to develope of high strength and corrosion reistant Mg-Zn system alloys by controlling microstructures and by adding of Cu elements. To produce optimum tesile strength,it is imperative to obtain effective grain refinment during casting. Optimal condition for grain size refining effect was obtained at the minmum composotion of 2wt% Cu or 1.5wt%So addition to Mg-6wt%Zn alloy.Age hardening behavior was experimented at the optimal compositions of the Mg-6wt%Zn, Mg-6wt%Zn-2wt%Cu and Mg-6wt%Zn-1.5wt%Si. The hardeness increment due to age hardening was at the Mg-Zn-Si alloy system. The improvement of corrosion resistanece by the addition with Cu is related to and increasing Zn/Cu ration in the intermatallic particles in the Mg-Zn system.Further improvements obtained by T6 treatment are related to the properties of the Mg-Zn phase,whih acts as a corrosion barrier by precipitating along the grainboundaries.Filiform corrosion observed soon after pit initiation and cellular form of pit propagation later in chloride media are explained in terms of solid solution matrix structure and the properties of air formed oxide.The information obtained from the fundamental research work is utilized in suggesting ways of improving the corrosion resistance of commercial AZ91.

응급환자에 대한 맥박산소측정기의 임상적 평가

안철민,이한식,조광현,황태식,김성규 대한응급의학회 1995 대한응급의학회지 Vol.6 No.2

Pulse oximetry is a noninvasive method of measuring blood oxygen saturation even before changes to the cardiopulmonary functions become apparent clinically. Therefore it has been widely excepted in many disciplines as a standard patient monitoring equipment. But its accuracy has been argued at low oxygen saturation levels. To determine the accuracy of the pulse oximetry in the emergency department where the patients presenting with respiratory difficulty are expected to have low oxygen saturation levels. Prospective, cross-sectional, paired measurements of oxygen saturation by two different pulse oxineters(SpO2) against oxygen saturation of arterial blood gas analysis(SaO2) was performed from May 1994 to September 1995 at two different university hospitals. Two pulse oxineters each with its digital probe were applied to the patient for the measurement of SpO2 simultaneously and arterial blood gas was drawn for analysis(ABGA) at the same time to measure SaO2. 98 patients who met the criteria mostly consisted of cardiopulmonary patients. There were no significant differences between mean SpO2(88.1±11.4, 88.2±10.0) of the two pulse oximeters and mean SaO2(88.7±11.4) from the arterial blood gas analysis(p=NS). Strong correlations were found(r=.80). But the regression declined as SaO2 decreased especially SaO2 < 90%. The pulse oximetry is potentially useful in patients with clinical signs of acute hypoxemia and patients receiving interventions that may produce acute hypoxemia, because of their ability to continuously monitor the oxygen saturation. But pulse oximetry along cannot identify the degree of hypoxemia or severity of distress. Therefore patients complaining of respiratory difficulty in an emergengy department, history and physical examination must be performed with pulse oximeter as a guide while backing it up with ABGA.

질소 기체의 다분자층 흡착을 이용한 BN, Alumina 및 Silica-Gel의 동공 크기 분포

안운선,조현우,곽현태,김영진 성균관대학교 기초과학연구소 1988 論文集 Vol.39 No.1

Multilayer adsorption isotherms of nitrogen on hexagonal boron nitride, γ-alumina, and silicagel powders are determined at the liquid nitrogen temperature using a gravimetric adsorption apparatus. The volume(V) of the adsorbed gas are plotted against the statistical thickness(t) of the adsorbed layer, and the t-method area are calculated from the slope of these V-t plots to compare with the BET area. The Frenkel-Halsey-Hill equation are used in calculating the statistical thickness. Pore-size distribution of the adsorbents are determined by using the improved method of pore-size distribution analysis proposed by Ahn et al. The cumulative surface area calculated from the results of these pore-size distribution analysis agrees very well with the BET area and the t-method area.

장거리 달리기 선수에서 횡문근융해와 생화학적 지표의 변화에 대한 연구

안선호,최석채,김태현,나용호,송주흥,이영진,조지현,최석준 대한신장학회 2000 대한신장학회잡지 Vol.19 No.5

당뇨병성 신경병증에서 근위부 비골신경전도 검사를 이용한 병태생리학적 접근

김동현,이강건,박종원,박태환,안병철,권오상 대한신경과학회 1998 대한신경과학회지 Vol.16 No.2

국부 안전율을 고려한 유한요소 사면안정해석

이종현,박용원,안태봉 명지대학교 대학원 1997 대학원논문집 Vol.1 No.-

In generally, slole stability analysis has performed by limit by equilibrium method(LEM) Using overall safety factor. Nowadays, however, numerical analysis techniques such as finite element method(FEM) is began to be used in slope stability analysis which considers nonlinear stress-strain behaviour with the advance of computer processor. FEM analysis has merits in reducing the over-or understanding problems of LEM analysis by adapting local safety factor concept and the nonlinearity in stress-strain behaviour of soil and rock. This study performs to develope a FEM computer program for slope stability analysis of soil and/or slope. The newly developed program is testified by the analysis results for several sample cases with existing LEM programs. The minimum safety factors of both analysis methods show good agreement, while the depth of failure surface of FEM analysis is larger than those of LEM analysis.

서울 남산 도시자연공원의 대기정화기능과 가치

조현길,조용현,안태원 江原大學校 附設 環境硏究所 2003 環境硏究 Vol.20 No.-

본 연구는 서울시 남산 도시자연공원을 대상으로 식생의 대기 CO₂SO₂및 NO₂흡수능을 계향화하여 대기정화에 기여하는 가치를 구명하였다. 활엽수림이 전체 식생면적의 약 54%를 차지하였고, 수령구조는 유목내지는 성장과저으이 수목들로 우점하였다. 평균 교목밀도와 기저면적은 각각 17.5주/100m², 2,580cm²이었다. 식생유형 및 영급별 단위면적당 대기정화능은 기저면적의 변화와 유관하여 영급이 높을수록 증가하였고, 동일 영급내에선 대체로 침엽수림보다는 온효림이나 활엽수림이 더 컸다. 식생유형 전체의 단위면적당 평균 CO₂저장량은 293.8t/ha이었고, 경제가치는 147백만원/ha이었다. 연간 흡수량은 CO₂ 24.6t/ha/yr, SO₂ 17.1kg/hr/yr및 NO₂ 43.9kg/ha/yr이었고 연간 경제가치는 13백만원/ha/yr이었다. 전체 식생명적은 총 72.100t의 CO₂를 저장하고 있으며, 해마다 CO₂6.040t/yr, SO₂4.200kg/yr, NO₂10.770kg/yr을 흡수하는 것으로 나타났다. 그 전체면적의 경제가치는 CO₂저장 약 361억원, 연간 CO₂SO₂및 NO₂흡수 31억원/yr에 상당하였다. 남산 도시자연공원은 해마다 시민 약 1,100인의 CO₂배출량, 2,800인의 SO₂배출량,1.160인의 NO₂배출량을 각각 상쇄시키는 중요한 역할을 담당하였다. 본 연구결과는 도시자연공원의 대기정화 가치를 홍보함은 물론, 보강식재 및 관리의예산확보에 필요한 설득력 있는 기반자료가 될 것으로 기대한다. This study quantified C0₂SO₂and N0₂uptake by vegetation for the Namsan Nature Park in Seoul, and explored values for the park to contribute to atmospheric purification. Broad?leaved forest accounted for about 54% of total forest area, and tree-age structure was dominated by a young; growing tree population. Tree density and basal area averaged 17.5 trees/100㎡ and 2,580c㎡/100㎡, respectively. Atmospheric purification per unit area by forest type and age class was greater in older age classes, associated with changes in basal area, and tended to be greater in broad-leaved or mixed forest than in coniferous forest for the same age classes. Mean CO₂storage per unit area for all the forest types and age classes was 293.8 t/ha and economic value of the CO₂storage was \147millions/ha. Annual uptake averaged 24.6 t/ha/yr for C02' 17.1 kg/ha/yr for 802 and 43.9 kg/ha/yr for N02, and economic value of the annual uptake was W 13millions/ha/yr. Total forest area stored 72,100t of CO₂and annually sequestered 6,040t/yr of CO₂4,200 kg/yr of SO₂and 10,770 kg/yr of NO₂. Economic value of atmospheric purification for the entire area amounted to approximately \ 36,100millions for the CO₂ storage, and \ 3,100millions/yr for the annual CO₂SO₂and NO₂uptake. The park played an important role through annually offsetting CO₂emissions from fossil fuel consumption by 1,100 persons, SO₂emissions by 2,800 persons, and NO₂emissions by 1,160 persons. The results from this study are expected to be useful not merely in informing the public of atmospheric purification values of urban nature parks, but in urging the necessity for replanting and management budgets.

도시녹지의 대기환경개선 효과 : 서울시 중구를 중심으로;Focusing on Jung-gu in Seoul

조현길,조용현,안태원 江原大學校 附設 環境硏究所 2003 環境硏究 Vol.20 No.-

This study explored effects of urban greenspace on improving atmospheric environmcnt, which is concerned with CO₂, SO₂and NO₂ uptake, and with reduction of summer air temperatures. The site of this study was focused on Jung-gu in Seoul. Tree density and cover were1.1trecs/l00 m₂and 12.5% respectively for the study area except forest lands. Atmospheric purification by greenspace was associated with changes in tree cover per unit area of each land use type. The mean C02 storage by woody plants was 19.4t/ha, and annual uptake averaged 2.2t/ha/yr for C0₂, 1.9kg/ha/yr for SO₂and 5.0kg/ha/yr for NO₂. Entire tree plantings in the study area played a significant role by annually offsetting CO₂emissions of about 1,8301 from fossil fuel consumption by 330 persons, SO₂emissions of 1,620kg by 1,080 persons, and NO₂emissions of 4,230kg by 450 persons. The smnmer air temperature was 3.6℃ cooler at a location with 54% cover of woody plants and 4.5℃ cooler at a forest site with 100% cover, compared to a place with no planting. A 10% increase of woody plant cover was estimated to decrease slimmer air temperature by approximately 0.6℃ until a certain level of canopy cover. Analyzing data from the Automatic Weather Stations in Seoul revealed that increasing tree cover decreased mean air tern-perature for the smruner season (Jun∼Aug) in a nonlinear function. Woody plant cover was the best predictive variable of summer temperature reduction. The results from this study are expected to be useful in emphasizing the environmental benefits and importance of urban greenspace enlargement, and in urging the necessity for planting and management budgets.

저혈청 배지에서 인간 전골수세포(HL-60)를 이용한 tPA 생산과 세포사멸기작에 관한 연구

김현구,성기돈,김태호,안주희,함문선,박진서,이현용 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.1

tPA 생산과 세포 사멸의 연구를 하기 위해서 인간 전골수세포가 배양되었다. 연속 관류 배양하에서 최대 tPA 생산량은 324 ng/ml이며 최대 세포 농도는 5.27×10 exp (6) cells/ml였다. Phorbol ester를 넣었을 때 tPA 생산량은 420 ng/ml까지 향상되었다. 형광 현미경으로 관찰했을 때, apoptosis는 세포 배양 초기부터 중반까지 우세했고 빠른 교반 속도에서도 우세했다. 그러나 necrosis는 세포배양 말기와 동결된 세포가 해동 되었을 때 우세했다. HL-60 was cultivated to produce tPA (tissue-type plasminogen activator) and study the mechanism of cell death. Maximum cell density and tPA production were obtained as 5.27×10 exp (6) cells/ml and 324 ng/ml, respectively under perfusion cultivation. tPA production was enhanced to 420 ng/ml in adding 160 nM of phorbol ester. The cells were gradually differentiated to granulocytes rather than proliferation. By Fluorescent microscope, apoptosis was prevailed except the death phase and in high agitation speed, but necrosis was prevailed in thawed cells and during the latter periods of the cultivation. It was also proved that tPA was most produced in apoptosis. To obtain higher tPA productivity, the cells must be maintained in apoptosis, not necrosis phase when the cells were dying.