농용(農用) 디이젤 엔진 연료(燃料)로서의 에타놀 이용(利用)에 관(關)한 연구(硏究)

유관희,배영환,유수남,Ryu, Kwan Hee,Bae, Yeong Hwan,Yoo, Soo Nam 한국농업기계학회 1982 바이오시스템공학 Vol.6 No.2

The objective of this study was to find out the technical feasibility of ethanol-diesel fuel blends as a diesel engine fuel. Fuel properties essential to the proper operation of a diesel engine were determined for blends containing several concentrations of ethanol in No. 2 diesel fuel. A single-cylinder diesel engine for a power tiller was used for the engine tests, in which load, speed and fuel consumption rate were measured. The fuels used in tests were No. 2 diesel fuel and a blend containing 10-percent ethanol and 90-percent No. 2 diesel fuel. The results of the study are summarized as follows. 1. It was not possible to blend ethanol and No. 2 diesel fuel as a homogeneous solution even though anhydrous ethanol was used. The problem of blending ethanol in No. 2 diesel fuel could be solved by adding butanol about 5% of the amount of ethanol in the blends. 2. Because ethanol had a much lower boiling point ($78.3^{\circ}C$ under atmospheric pressure) than a diesel fuel, it was necessary to store ethanol-diesel fuel blends airtight in order to prevent them from evaporation losses of ethanol. 3. The addition of ethanol to No. 2 diesel fuel lowered the fuel viscosity and the cetane rating, but a blend of 10% ethanol and 90% diesel fuel had a viscosity and a cetane rating well above the KS minimum values for No. 2 diesel fuel. 4. At the rated speed, the specific fuel consumption of No.2 diesel fuel was lower than that of the 10% ethanol blend for the almost entire range of load. However, under the overload condition the specific fuel consumption was lower for the 10% ethanol blend. 5. Under the variable-speed full-load tests, both fuels produced approximately the same torque and power. At the speeds of 1600rpm or below, the specific fuel consumption of No. 2 diesel fuel was lower than that of the 10% ethanol blend. At the speeds of 1600rpm or above, however, the specific fuel consumption was lower for the 10% ethanol blend. 6. At the ambient temperature above $15^{\circ}C$, the use of the 10% ethanol blend in the engine created a vapor lock in the fuel injection pump and stalled the engine. The vapor locking problem was overcome by chilling the surroundings of the fuel injection pump and the cylinder head with water.

다중 참여자 3차원 웹 브라우징 시스템을 위한 서비스 통신 규약 설계

유관희 충북대학교 컴퓨터 정보통신 연구소 1997 컴퓨터정보통신연구 Vol.5 No.1

본 논문에서는 인터넷을 통하여 3차원 가상 공간상에서 다중 참여자를 지원하는 응용서비스, 예를 들어 화이트보드(White board) 지원 대화방, 시합 및 가상 공간 설계 서비스등을 가능하게 하는 다중 참여자 3차원 웹브라우징 시스템을 구현하기 위한 효율적인 통신 규약을 제안한다. 본 통신 규약에서는 3차원 가상공간, 동적 객체 및 참여자를 위한 참여자 표현을 위해 VRML 1.0 화일을 사용하고 인터넷상의 응용 서비스 지원을 위해 웹의 통신 규약일 HTTP을 사용한다. 더욱이 가상 공간상의 다중 참여자와 동적 3차원 객체 조직을 위해 참여자의 변화 정보 및 참여자간의 대화정보와 3차원 동적 객체 정보 전송 기능을 제공한다. In this paper, we propose an efficient service protocol for implementing a 3D Web browsing system. It is possible for the 3D Web browsing system to design application services such as chatting with board, games and design of virtual spaces, which support multi-user to represent 3D virtual spaces, dynamic objects, and avatars for users, and a HTTP on Internet is also used as the low layer of the protocol. In addition, the protocol provides the changing information of avatars and dynamic 3D objects, and the chatting one among avatars for manipulating multi-user and dynamic 3D objects in a virtual space.

동적 X3D 콘텐츠의 영상 품질 향상을 위한 다중텍스쳐링 기법의 적용

유관희,하종성,Yoo Kwan-Hee,Ha Jong-Sung 한국콘텐츠학회 2006 게임&엔터테인먼트논문지 Vol.2 No.1

본 논문은 텍스쳐와 같은 물체의 속성이 동적으로 변하는 인터넷 3D 콘텐츠에서 영상 품질을 향상시키기 위한 다중텍스쳐링 기법에 관한 것이다. 다중텍스쳐링과 관련된 X3D 노드들을 최근의 X3D 뷰어를 중심으로 실험하여 이들의 활용 방법과 제약점을 알아보고 이를 바탕으로 향후 사용자 요구 및 그래픽가속기의 발전에 따른 차세대 X3D 뷰어의 개발 방향에 대하여 논의한다. This paper is concerned with the techniques of multitexturing for increasing the image quality of 3D contents in the Internet, where the attributes of objects such as textures are dynamically changed. First we explain the empirical results of implementing the X3D nodes related with the multitexturing in the recent X3D viewers. Next we discuss the directions for developing the next-generation of X3D viewers that satisfy the user requirements and the advanced graphics accelerators.

회계정보시스템 설계시 내부감사인과 시스템분석가 간의 인식차이에 관한 연구

유관희,허춘 韓國公認會計士會 2000 회계·세무와 감사 연구 Vol.36 No.-

본 연구는 컴퓨터화된 회계정보시스템을 설계하는데 있어 시스템분석가에게만 의존하는 것보다 내부감사인이 동참하는 것이 보다 우수한 통제능력을 갖춘 시스템을 개발할 수 있을 것이라는 전제에서 진행되었다. 이 전제를 간접적으로 검증해보기 위해, 내부감사인이 시스템분석가보다 회계시스템의 내부통제기능을 평가,분석하는데 한 차원 높은 자질을 가지고 있는가를 간단한 시나리오분석을 통해 알아보았다. 본 연구의 결과는 시스템분석가들과 내부감사인들간에 내부통제요소를 찾아내는 데나 통제요소의 중요성을 평가하는 데에 별 차이가 나지 않음을 보여주고 있다. 즉, 시스템 개발과정에 내부감사인이 참여하여야만 시스템의 통제능력이 더욱 향상된다고 결론내리기는 어렵다는 점을 시사해주고 있다. The major objective of this study was to investigate whether internal auditor involvement in the design of computerized accounting information systems might result in an improved system. To this effect, this study examined whether a difference existed in the analysis of internal controls between systems analysts and internal auditors. The internal auditors were considered superior to the systems analysts in inserting control features within a system. The primary finding of this study was that no significant difference was found between the groups in their identification of internal control measures, or in their evaluation of the importance of internal control measures. This result implies that the participation of internal auditors does not always guarantee a superior computerized AIS.

Growth Inhibition Profile of an Antibacterial Entity from Paenibacillus DY1 Isolated from Korean Soil against Multidrug Resistant Enteric Bacterial Strains and Its Characterization

유관희,권순일,신은석 대한의생명과학회 2007 Biomedical Science Letters Vol.13 No.1

Due to wide abuse of antibiotics both in human and livestock use, the advent and spread of multidrug resistant (MDR) pathogens becomes a serious health problem all over the world. Since the development of new antibiotics is at a standstill in pharmaceutical industry, the choice of therapeutic antibiotics is getting narrower. In this study, in an effort to search new antibiotics, the antimicrobial activity of Paenibacillus DY1 isolated from Korean soil was characterized on its growth inhibition spectrum against various health threatening MDR strains, with its stability and chemical structure. Extracellular culture filtrate of Paenibacillus DY1 effectively inhibits the growth of all the tested MDR enteropathogenic Eshcherichia coli, enterohemolytic E. coli, and enterotoxigenic E. coli strains, at a similar level to that on the nonresistant control E. coli strains. It showed significant growth inhibition effect against the causative agents of class one legal communicable disease, MDR Salmonella typhi, MDR Salmonella paratyphi A, food poisoning bacteria, MDR Salmonella typhimurium, and other MDR Salmonella spp. The growth of all of 10 different MDR Shigella spp. strains and 6 different Vibrio spp. strains tested was also inhibited. The antimicrobial activity of Paenibacillus DY1 was well preserved after heat treatment, and was also stable in both alkaline and acidic environment. The antimicrobial activity was partially purified with Diaion HP20 column and TLC. By NMR study, the putative structure of the activity was postulated as an alkane having hydroxyl groups.

합성배지에서 Stropharia rugosoannulata 가 생산하는 섬유소분해효소에 관한 연구

유관희,장형수 한국균학회 1999 韓國菌學會誌 Vol.27 No.2

For the purpose of utilizing cellulose resources by cellulolytic enzymes of Stropharia rugosoannulata, it's cultural conditions for the prodution of cellulolytic enzymes in synthetic media were investigated. The optimum pH for the production of Avicelase and β-glucosidase was pH 5.0, while that of CMCase was pH 4.0. The optimum temperature for the production of Avicelase, CMCase and β-glucosidase was 40℃. Among the carbon sources, xylose was good for the production of CMCase and β-glucosidase, but maltose was good for the production of Avicelase. The optimum concentration of the carbon sources for the production of CMCase, Avicelase and β-glucosidase was 1.0, 0.8 and 1.1 %, respectively. As inorganic nitrogen sources, NH₄Cl was good for the production of all the three cellulolytic enzymes. The optimum concentration of NH₄Cl for the production of CMCase was 0.3% while that of Avicelase and β-glucosidase was 0.4%. As organic nitrogen sources, malt extract was good for the production of all the three cellulolytic enzymes. The optimum concentration of organic nitrogen for the production of β-glucosidase was 1.3% while that of CMCase and Avicelase was 1.0%. As the mineral sources, CoCl₂ good for the was good for the production of all the three cellulolytic enzymes. The optimum concentration of CoCl₂ for the production of all the three enzymes was 0.35%.

農業機械要素의 스트레인 게이지 應用에 관한 調査硏究

柳寬熙,鄭昌柱,高學均,崔在甲 農科大學 農業開發硏究所 1980 農業開發硏究 報告書 Vol.1 No.1

디지털 교과서 표준화 현황

유관희,유재수,이석재 한국정보과학회 2008 정보과학회지 Vol.26 No.6

볼록 이차 광원으로부터 완전음영부를 구하는 최적 알고리즘

유관희 충북대학교 컴퓨터 정보통신 연구소 1999 컴퓨터정보통신연구 Vol.7 No.2

3차원 공간상에서 볼록 영역 광원이 주어진 물체를 비추면 각 객체에 대해 두 가지 유형의 그림자 볼륨, 즉 주어진 객체에 의해 부분적으로 가려지는 그림자볼륨과 완전히 가려지는 그림자 볼륨이 생성된다. 우리는 이것을 각각 반음영부(penumbra)와 완전음영부(umbra)라 한다. 본 논문에서는 원, 타원, 구, 타원체, 실린더 등과 같은 볼록 이차 광원으로부터 하나의 다각형에 대해 완전음영부를 계산하는 최적 알고리즘을 제시한다. 그리고 구해진 완전음영부를 렌더링(rendering),과 워크스루우(walkthrough)에 어떻게 응용할 것인지를 제시한다. An area light source in the three dimensional space shines past a scene polygon, to generate two types of shadow volumes for each scene polygon, i.e., one with partial occlusion and the other with the complete occlusion. These are called, penumbra and umbra, respectively. In this paper, we propose an optimal algorithm for computing the umbra of a scene polygon from convex quadric light sources such as circles, ellipses, spheres, ellipsoids and cylinders. And we also present how to apply the computed umbra to rendering and to walkthrough in computer graphics.

이앙기 식부긱구의 기구학적 분석

유관희 한국농공학회 1972 한국농공학회논문집 Vol.14 No.3