• Current Industrial and Technological Trends in Aerospace
• /
• v.6 no.1
• /
• pp.35-43
• /
• 2008

Technical trends of propulsion system for small aircraft are investigated. Currently, most small aircraft are equipped with piston engine, turboprop and turbofan engines, and the technology development is going continuously. For piston engines, new diesel engines are arising besides gasoline engine. The diesel engines use relatively low-cost and easy to get fuel(Jet A), so the demand for small aircraft is getting increased, and new engines with high reliability and efficiency are being developed. For gas turbine engines, application of small turbofan is getting increased for newly arising VLJ market and the engine demand will be rapidly increased in the future. On the other hand, some electric propulsions without fossil fuels are being developed without high cost of fuel and environmental effects. In the future, propulsion system for small aircraft will be developed having enhancement of performance and efficiency with higher reliability and safety.

• Cartoon and Animation Studies
• /
• s.29
• /
• pp.151-172
• /
• 2012

Game production education in a university is very important because it is the stage for completing a game education course as well as for determining a future of game industry. In order to perform various experience and creative learning, it should be able to effectively use a computer infrastructure representing the knowledge and information society for the purpose of obtaining and re-processing information necessary for game production through prediction of directions of game industry as well information technology. This research is focused on an effective game engine education for students whom want to become game graphics designers. The purpose of this study is to draw a lesson of game production utilizing game engines and it enables practice-focused class for game production. It also allows the class participant to manufacture prototypes without support from game programmers for their outcomes of works planned during the game production class. The theoretical background of game production compared and analyzed exemplary game engines. Based on the result, the study selected Unity 3D engine and conducted the research on the background where the Unity engine has been selected and its characteristics. In addition, this study provided an example of game production utilizing a game engine, and also described the details of actual realization. This study selected Torque3D with the Unity in order to identify the purpose of this study and efficiency of learning. Thus, the previous situation is that the class remained in making a game plan during the course of game production project and, students whose major is not game programming. Now, it is necessary for students to make many efforts to make a game in an active and positive attitude by utilizing a game engine beyond the previous method of class.

• Journal of the korean Society of Automotive Engineers
• /
• v.18 no.3
• /
• pp.1-7
• /
• 1996

이상 소개한 바와 같이 미쓰비시의 경우 현상의 기술로서도 실린더내 분사는 4l 클래스 엔진까지 확대가능하고 앞으로 더욱 엄격해질 배출가스의 규제와 저연비의 요구로 디젤엔진에 대신하여 소형트럭에까지 탑제가 확대될 것으로 추측된다. 그리고 이와 같은 초희박연소에 의한 저연비와 체적효율 향상에 따른 고출력의 양립은 지구환경보호측면에서도 크게 기대할 새로운 기술의 개가라 할수 있을 것이다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.05a
• /
• pp.41-49
• /
• 2001

최근의 대형 디젤 엔진은 고성능, 고효율 및 제작비용 절감 등의 요구에 따른 경량화, 유연화 추세로 설계되고 있는 한편, 엔진 자체에서 발생하는 고유의 큰 기전력 (가스폭발력, 왕복동 관성력, 각종 우력) 때문에 항상 진동 문제에 노출되어 있다. (중략)

• Journal of the KSME
• /
• v.30 no.6
• /
• pp.535-541
• /
• 1990

소규모 가스엔진 cogeneration 시스템의 국산화 개발을 위해 성능실험장치를 설계. 제작하고 성 능실험을 하였다. 성능실험결과 시스템의 에너지 이용률이 최고 73.6%에 달해 고효율 에너지 이용 시스템임을 입증하였다. 본 실험은 과기처 특정연구과제 "단위건물용 엔진구동 cogeneration 시스템 개발 연구"의 일부로서 수행된 것이다.서 수행된 것이다.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.13 no.2
• /
• pp.128-134
• /
• 2008

The variable speed engine generator set is interested for an isolated power system due to reduced fuel consumption and less emission. However, because of sluggish dynamic behavior of the internal combustion engine the power quality would be degraded during the sudden load power surge, where the power required by the load is not available by the engine due to the reduced engine speed. An isolated power system based on variable speed engine with a super-capacitor bank can improve dynamic characteristics under such a sudden load change, and power quality, fuel consumption, and pollutants can be improved remarkably. Also, it is verified by the computer simulation that the inverter of 3phase-4leg is compatible to the isolated power system with unbalanced load. In this paper, the feasibility of the system has been verified based on a 26kw commercial diesel engine system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.1057-1059
• /
• 2017

In development of liquid-propellant rocket engine, engine gimbaling requires various types of bellows movements and cryogenic insulation is applied with movement-based design and material on each axial and circular bellows. Cryogenic insulation of Bellows for high pressure line and recirculation line are necessary to maintain cryogenic temperature for engien efficiency and protect from heat transfer and radiation of high temperature components during engine gimbaling.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2004.10a
• /
• pp.423-426
• /
• 2004

인트라넷에서는 증가하는 웹문서의 검색을 목적으로 웹 검색엔진의 도입이 활발히 진행 중이며 대부분 찾아야할 키워드를 알고 접근하는 검색엔진 형태이다. 그러나 사용자가 무엇을 찾아야 하는지 모르는 경우 웹문서 분류체계는 효율적인 방법을 제시할 수 있다. 일부 구축되어 있는 분류체계는 수작업에 의한 분류로 인해 증가하는 웹문서의 양에 효율적으로 대처하기 곤란하므로 자동분류기법을 활용한 분류가 더 효율적일 것이다. 본 논문에서는 국방인트라넷의 수작업으로 구축된 분류체계를 대상으로 용어 가중치를 계산하는 방법을 달리하여 다양한 분류기법을 적용하여 성능을 비교평가하고 웹문서 자동분류시스템에 적용하여 분류성능의 향상을 도모하고자 한다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.05a
• /
• pp.159-162
• /
• 2008

In this study, various cycles of liquid rocket engines were surveyed and specifically gas generator after burning cycle was investigated for upper stage motors. The engines for the upper stage can be categorized into three group based on the cycles and propellants at the diagram. Kerosene engines which adapt the gas generator after burning cycle and are located in the region II, are characterized for high combustion pressure and complexity. This cycle usually needs more than two pumps to use the turbine power efficiently. The fuel line can be divided into the gas generator line and the combustor line, and only the gas generator line is need to be pressured more because the combustion pressure in the gas generator is much higher than that of the combustor. Basically, all the oxidizer goes into the gas generator and than to the combustor, thus the auxiliary LOx pump is not critically necessary. However, for the various reasons, the LOx line requires a booster pump. A gas generator after burning cycle engines produces relatively high specific impuls than that of the open cycle engines. Thus it is suitable for upper stages of launch vehicles.

• Journal of the Korean Society for Library and Information Science
• /
• v.34 no.2
• /
• pp.117-133
• /
• 2000

This study evaluated two Korean search engines, Korean AltaVista and Naver, using user-based measures by Su(1998). Measures are based on four evaluation criteria: efficiency, precision, validity of the links, user satisfaction. For this study, users conducted searches on two engines with their own search queries and performed relevance judgement. Study results indicate that efficiency, validity of the links, and user' s satisfaction ratios of system features are significantly different between two search engines, although there is no significant difference of precision. This study can be used as a framework for usercentered evaluation and utilized to enhance Korean search engines.