• Journal of Mechanical Science and Technology
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• v.15 no.6
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• pp.776-787
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• 2001

The turbofan engine performance analysis for a medium scale commercial aircraft was carried out and the LQR control scheme for performance optimization was studied. By using scaled component maps from well-known CF6 engine characteristics, the steady-state performance analysis result was compared with BR715-56 engine performance data. The transient performance analysis was performed with four fuel schedules. The linear simulation was done at the maximum take-off condition. The real time linear simulation was performed by interpolation of the system matrices, which used the least square method as the function of LPC rotational speed. By using linear system matrices of design point, the LQR controller which used control variables for the fuel flow and the LPC bleed air was designed.

• Radiation Oncology Journal
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• v.35 no.2
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• pp.185-188
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• 2017

Primary liver tumor, especially hepatocellular carcinoma (HCC), is a common cause of cancer death worldwide. The incidence is generally higher in Asian countries than in western countries. Carcinogenesis of HCC is often associated with hepatitis viral infections. Current standard treatment of HCC is surgical resection or transplantation in patients with early stage disease. However, the patient with advanced stage disease, surgical resection is often limited. Sorafenib or other treatment modalities are not so effective as well. We report a case of unusual radiation super-sensitivity in advanced stage HCC, and review the literature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.2
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• pp.126-132
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• 2017

The power conversion efficiency of organic polymer solar cells was enhanced by introducing a ferroelectric polymer layer at the interface between active layer and metal electrode. The power conversion efficiency was increased by 50% through the enhancement of the open circuit voltage. To investigate the role of the ferroelectric layer on the dissociation process of the excitons, non-radiative portion of the exciton decay was directly measured by using photoacoustic technique. The results show that the ferroelectric nature of the buffer layer does not play any roles on the dissociation process of the excitons, which indicates the efficiency enhancement is not due to the ferroelectricity of the buffer layer.

• Particle and aerosol research
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• v.12 no.3
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• pp.103-107
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• 2016

We conducted experiments on mask filters. We measured filtering efficiencies of several new mask filters which were manufactured by disassembling and reassembling of one type of mask filter. New filter (A+C: combination of the first layer and the third layer of the tested mask filter) showed the highest efficiency (97.7%) with the respiratory resistance of 98 pa.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.295-298
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• 2002

In the analysis of the mass distribution and SMD (Sauter Mean Diameter), planar laser imaging technique Is a convenient and useful one when compared to the mechanical patternator or PDPA (Phase Doppler Particle Analyzer). But for the accurate usage of this laser technique, it is required to compensate the signal attenuation and to find the attenuation coefficients. In the present research, we considered effects of the spray distributions on the attenuation coefficient and improved the accuracy of planar laser imaging technique by the reduction of errors issuing from the signal attenuation.

• Journal of the Korean Society for Library and Information Science
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• v.23
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• pp.1-31
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• 1992

The present study aims at a systematic access to EC information. EC information is the outcome of the complex organizations, the continuous changes in functions and the subsequent changes in policies. An attempt for an effective approach to the information requires the examination of the organizational structures and changes, the processes involved in formulating and implmenting the information policies, and the infrastucture for information. Information activities of the major organizations of EC have been examined with a special reference to the Commission of European Communities. The Commission is the EC institution from which the majority of the EC's documentation originates. The information functions of the Commission have been studied in such categories as information production and distribution, authorizing services, and information services to the public.

• Proceedings of the Korea Contents Association Conference
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• 2014.11a
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• pp.111-112
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• 2014

본 연구는 사이버대학생들의 학업스트레스, 학업지연 그리고 학업소진 간의 관계를 살펴보고, 그 중 학업지연의 매개 역할을 검증하고자 하였다. 또한, 이러한 결과가 참여자들의 사이버대학 참여 동기 수준에 따라 차이가 있는 지를 검증하고자 하였다. 본 연구에는 283명의 사이버대학 재학생이 참여하였다. 분석 결과 학업지연은 학업스트레스와 학업소진 간에 부분매개 역할을 하는 것으로 나타났으며, 사이버대학 참여 동기 수준에 따라 학업지연의 역할은 차이를 보였다. 이러한 결과를 바탕으로 본 연구가 가지고 있는 함의와 한계점에 대해 논의하였다.

• Journal of the Korean Society for Library and Information Science
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• v.13
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• pp.143-181
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• 1986

The present study aims at figuring out the potential benefits occured from the practical pplications of the information analysis center concept in Korea. The R&D requirements in Korea at the moment is such that the highly specialized and sophisticated information services are essential. With the general information infrastructure still embryonic the best possible answer is sought in a specialized tried-out method, namely, the information analysis center which is to be planned and serviced as an integral part of a specific research project. The article examines the information exchange activities of scientists; the backgrounds of the development of the information analysis center concept into 'a technical institute'; the processess of information analyses and evaluations; the effects and values of an analysis center; and the applicabilities of the information analysis center concept with a special regard to the developing country's needs. The conclusion confirms of the potential benefits of the information analysis center type facilities for the current needs of the Korean research and development environments.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.645-647
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• 2018

최근 IoT의 기술의 발달로 사용자 인식에 관한 연구가 주목을 받고 있다. 사용자 인식은 각 사용자만의 특징에 근거하여 특정 사용자를 인식하는 기술이다. 사용자 인식과 관련하여 홍채나 지문인식 등과 같은 생체 인식, 얼굴 인식 그리고 걸음걸이 인식 등에 관한 연구들이 진행되고 있다. 다양한 방식은 각각의 인식률을 높이기 위해 노력하고 있지만, 인식하고자 하는 사용자의 상황에 따라 인식률에 영향을 받게 된다. 본 연구에서는 다양한 방식을 여러 단계로 구성하여 다양한 상황에 놓인 사용자를 인식하기 위한 방법을 연구한다. 제안 시스템은 드론에서 촬영된 영상을 수신하는 것을 기반으로 하여 얼굴인식과 걸음걸이 인식을 이용한 방식이다. 1차적으로 사람의 얼굴을 탐지를 하고, 사람의 얼굴이 탐지되었을 때는 얼굴 인식을 수행한다. 탐지하지 못했을 경우 걸음걸이 인식을 수행하여 인식률을 향상시킨다.

• Journal of the Korean Society for Library and Information Science
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• v.8
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• pp.209-232
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• 1981

The study aims at bringing to the attentions of Korean librarians the ways and means with government publications, which had hardly been brought to the scene yet. It deals with the characteristics of archives and the nature of an archival arrangement based on 'the principle of provenance' ; the characteristics of government publications in relation to the adequacy of an archival arrangement; the three major devices in use for organizing government publications; and introduction to two sample classification systems. The study concludes with a notion that a vast reservoir of information sources(government publications) should be tapped and put to the use of researchers without delays inherent in library processing. It advocates an archival arrangement for economy and efficiency.