• Journal of the Korean Society for information Management
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• v.15 no.2
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• pp.47-68
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• 1998

Although the research information resources on Internet are spread out on thousands of computers, it is not always easy to get them on the right time by the right manner. The purpose of this study is to use DDC(Dewey Decimal Classification) scheme in subject-based directory search engine for research information resourcees to aid retrieval on the Internet. For the design of classification code, this study followed 'systematic order' of DDC to arrange subjects from the general o the specific in a logical order, and for the design of classification dictionary, 'Relative Index' of DDC was used to bring together the various aspects of subjects.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.102-109
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• 2003

The number of engines for fighters has been decided by thrust required and available engines at the time since the beginning of the jet age. However, many factors such as combat effectiveness, survivability, performance, and cost were considered as engine technology has been progressed. From the vietnam war and desert storm, a twin engine fighter was shown slight superiority to a single engine one in an vulnerability，but single engine fighters were a little predominant in susceptibility This paper includes the trade-off study results on the number of engines for the supersonic light attack aircraft with single and twin engines. Twin engine configuration is 8%, 26%, and 13% higher than single engine one in MTOGW, Flyaway Cost, and LCC respectively. Little difference has been found in RM&S, Maneuver and field performance. According to the factors above, single engine fighter is profitable for low class and twin engine one for medium and higher class.

• Journal of the KSME
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• v.32 no.10
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• pp.830-836
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• 1992

엔진ECU의 개발현황과 타 제어장치와의 통합 문제 특히 트랙션 제어와의 통합 문제를 개괄적 으로 서술하였다. 현대의 자동차에 있어서 전자 제어장치는 필수 불가결한 요소로서 등장한 지 오래고 그 비중이 날로 커지고 있음은 주지의 사실이다. 국내에서의 자동차 전자제어장치의 개발이 최근에 와서야 그 중요성의 인식이 제고되고 있어 후발 주자로서의 시기적, 기술적 어 려움이 예상된다. 이러한 가운데 더욱 효과적이고 체계적인 연구를 위해서는 업계와 학계 간의 긴밀한 협조체계가 필요하며 선진국과의 격차를 빠른 시일내에 줄여 나가기 위해서는 업계 간의 공동 노력이 절실하다 할 수 있다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1994.06a
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• pp.34-39
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• 1994

자동차엔진의 고성능화 및 경량화는 지속적으로 추구되어 왔으며, 향후에도 배기가스 저감 및 연비향상등의 문제 해결을 위한 기술개발이 지속될 것으로 예상된다. 이와 같은 엔진의 지속적인 성능향상에 따라 엔진유의 요구성능도 증가일로에 있는데, 특히 엔진유에 가해지는 열부하의 증대로 고온산화에 의한 열화가 촉진되기 때문에 이와 관련된 엔진유의 고성능화가 절실히 요구되고 있다. 국내에서도 가솔린엔진유의 신규격인 API SH 및 ILSAC GF-1 규격을 만족하는 신제품들이 개발되어 상업화되어 있다. 그러나, 이러한 고성능제품들의 성능이 구규격 제품인 API SG, SF, SE, SD 등의 제품과 어떻게 차이가 있는지에 대한 체계적인 연구가 되어있지 못한 실정이다. 본보에서는 성능등급이 서로 다른 가솔린엔진유에 대한 성능차이를 조사하기 위하여 수행항 실험결과를 보고하고자 한다.

• Journal of the Korean Society for Library and Information Science
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• v.32 no.3
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• pp.207-230
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• 1998

Because of a rapid increase of information available through web site, a user often falls into confusion of which web sites should be visited for his information needs. If a web site search engine can classify web sites according to their subject or topics, it can help the user to determine which web sites are worth accessing and thus to easily acquire relevant information. In this study, I propose new classifying system with a two level hierarchy and 57 items.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.7
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• pp.599-611
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• 2016

This paper proposes a cognitive engine platform that enables dynamic spectrum access(DSA) based on a spectrum sharing system for the military tactical network environment. The current military tactical wireless communication system is increasing need to secure a supplementary wireless spectrum to ensure that multiple wireless networks for different weapon systems co-exist, so that tactical wireless communication between the same or different systems can be operated effectively. This paper examined policy development and research activities engaged by the U.S. and European countries on wireless spectrum sharing to secure more spectrum. It also introduces the current status of cognitive engine development, which is the core technology of tactical wireless communication for DSA. In addition, based on the investigation performed into the latest trends, we propose a platform structure for a cognitive engine based on a spectrum sharing method where more frequencies can be added for tactical radio communication, so that DSA can be realized, and wireless networks of different weapon systems can co-exist.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.3
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• pp.74-82
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• 2000

The concept and characteristics of the propulsion systems for the next generation flight vehicles are described in this paper, where Hey are grouped into air breathing engine, rocket engine and combined cycle engine according to the feeding system of oxidizer. Air breathing engine has its good reusability and superior performance at low altitude, but its usage is limited at high altitude due to the decreased air density. Rocket engine can be used over the wide range of altitude, but it has disadvantages in low specific impulse and high cost. The several types of combined cycle engine, which are being developed by the leading countries in the aerospace, are highlighted as a remarkable candidate for the next generation propulsion system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.548-551
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• 2010

A 150 lbf-thrust class micro turbojet engine has been developed. The engine could be applied to power plant for small aviation vehicle such as UAV, decoy and anti-radar missile and was designed with concepts that has small size, low-cost and high performance. A prototype was manufactured and performed the ground static test and high altitude test. This paper outlines the features and layout of 150 lbf turbojet engine and also describes the design characteristics and test results of the engine and components.

• 기계와재료
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• v.19 no.3 s.73
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• pp.50-63
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• 2007

• Archives of design research
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• v.17 no.4
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• pp.79-88
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• 2004

This study is aimed to grasp the organization of Internet information resources and to infer the characteristics of resource search engines so that criteria may be established to classify and evaluate Internet information resources. In addition, the author has compared and analyzed interior design classification systems of directory sites of each subject that provide classification system based on the Internet, foreign sites to be used to search for information, and domestic information-specialized sites in order to set up models of interior design classification systems of directories of each Web subject. The systems have been analyzed against such four measures as comprehensiveness of the subject scope, logicality of classification systems, preciseness of subject terms, and effectiveness of searches. Information of interior designs is mixed with that of related fields, and so its information search and classification are not organized systematically. The author has analyzed such a problem so as to present models of search engine classification systems for interior design information classification after considering both academic and practical aspects.