• 교육시설 논문지
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• 제26권5호
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• pp.25-36
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• 2019

School gymnasium is a multi-purpose large space building for various events and physical education activities, and is a facility that requires an approach to the desirable structural design, besides mechanical problems of structure against loads. For the integrated structure design concerning the architectural features, the major considerations of gymnasium planning that are the internal and external shape of the gymnasium, the space scale with structure members, the structural efficiency by members weight reduction and openness of the gymnasium space will have to take into account in the structural planning. From this point of view, the several cases of the school gymnasium were investigated and the parametric analyses were performed to the models using the various structural system. The parameters were the composition elements of structure system that are profile of structure, rigidity of member, connection and anchorage and stability. At the result, It was presented that the profile of structure member was the most influential factor to structural efficiency and the effect of the form and space of gymnasium. Also the design informations of structure design having the various feature of form and space were presented for the initial gymnasium planning.

• 한국전자파학회논문지
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• 제27권5호
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• pp.407-415
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• 2016

무선 통신의 최근 동향을 살펴보면 에너지 효율적 전송의 중요성이 강조되고 있다. 본 논문은 multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM) 무선 시스템에서 에너지 효율성을 최대화하기 위해 기계학습 기술을 사용하는 적응형 전송을 고려한다. MIMO-OFDM 시스템의 채널 상태를 효과적으로 나타내기 위한 two- dimensional capacity(2D-CAP) feature space와 classification 기술을 통해 에너지 효율적인 적응형 전송을 수행하는 machine-learning-based bit and power adaptation(ML-BPA) 알고리즘을 제안한다. 모의 실험 결과를 통해 2D-CAP이 본 논문이 고려하는 무선 채널 상태를 정확하게 나타내며, 이를 통해 적응형 전송의 성능을 향상시킴을 확인하였다. 또한, ordered postprocessing signal-to-noise ratio(ordSNR)를 포함한 다른 feature space들과 직접적인 비교를 통해 2D-CAP이 전송 성능이나 복잡도 측면에서 뚜렷한 이득을 가짐을 확인하였다.

• 대한기계학회논문집B
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• 제33권12호
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• pp.952-960
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• 2009

Selective Catalytic Reduction (SCR) system is a high-effective NOx reduction technology in diesel engines. As the emission standard of diesel engines is more stringent, vehicle manufactures makes efforts on emission technologies. This paper discusses the performance of Urea-SCR system according to the engine operating conditions in a passenger diesel engine. Engine test results in this paper show that it is important to consider the catalyst temperature and space velocity to obtain high NOx conversion efficiency. In condition of high catalyst temperature, over 90% NOx conversion efficiency is indicated. However, when catalyst temperature is low, NOx conversion efficiency was decreased. Also, it was shown that space velocity mainly effects on the DeNOx performance under 220 degree celsius of SCR catalyst temperature. As the urea injection pressure was decreased, NOx conversion efficiency was declined. It is concerned about urea droplet atomization. This work shown in this paper can lead to improved overall NOx conversion efficiency.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제25권4호
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• pp.81-91
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• 2019

Purpose: Since infectious disease hospitals are premised on emergency operations, the operational efficiency of secured personnel, equipment, facilities, etc. is relatively low. In order to increase such normal operational efficiency, it is necessary to flexibly operate facilities and operations during normal and emergency times. The purpose of this study is to suggest the architectural planning method focusing on the space composition and circulation of the regional infectious disease hospital which can increase the operational efficiency in the private hospitals. Methods: Through literature review, functional requirements of infectious disease hospitals were identified, and related personnels inter-views and field surveys were conducted to understand the spatial composition and circulation requirements of infectious disease hospitals. Results: Through the complete separation between the negative pressure zone and the general zone, even when the negative pressure zone is completely closed, the general zone should be operated separately to achieve operational efficiency. In addition, the separation of the negative pressure zone and the general zone should simultaneously consider the optimal space configuration and movement for each function while the zone settings match in the floor plan of each department and the overall cross-sectional configuration of the hospital. Implications: Infectious disease hospitals intended to be installed in private hospitals should not apply excessive space just for safety reasons and should plan to ensure their operational efficiency.

• 한국정보과학회논문지:시스템및이론
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• 제33권9호
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• pp.615-625
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• 2006

최근 차세대 메모리 기술이 급격히 발전하여 FeRAM과 PRAM과 같은 비휘발성 메모리의 상품화가 진행 중이다. 이러한 차세대 비휘발성 메모리(NVRAM)는 메모리와 저장 장치의 속성을 모두 만족시켜 데이타를 영속적으로 저장할 뿐 아니라 빠른 데이타 임의 접근을 가능하게 한다. NVRAM에 자주 변경되는 객체를 영속적으로 저장하기 위해서는 네이밍, 회복, 그리고 공간 관리와 같은 파일 시스템의 핵심 기능이 모두 필요하다. 그렇지만 기존 파일 시스템과 최근에 개발된 NVRAM 용 파일 시스템 모두 공간 효율이 낮으며, 어떤 경우 50% 정도에 불과하다. 따라서 상대적으로 고가인 NVRAM을 활용하기 위하여 공간 효율성이 뛰어난 익스텐트(extent) 기반의 NEBFS (NVRAM Extent-Based File System) 파일 시스템을 설계하였다. 그리고 기존 파일 시스템과 NEBFS의 공간 효율성을 비교 분석하였으며, 아울러 NEBFS를 구현하고 NVRAM이 탑재된 보드 및 NVRAM 에뮬레이션 환경에서 공간 효율성을 측정하여 분석 결과를 검증하였다. 이러한 실험 결과는 NEBFS의 공간 효율이 기존 파일 시스템보다 우수함을 보여 준다.

• Nuclear Engineering and Technology
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• 제47권6호
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• pp.678-699
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• 2015

Although the harsh space environment imposes many severe challenges to space pioneers, space exploration is a realistic and profitable goal for long-term humanity survival. One of the viable and promising options to overcome the harsh environment of space is nuclear propulsion. Particularly, the Nuclear Thermal Rocket (NTR) is a leading candidate for nearterm human missions to Mars and beyond due to its relatively high thrust and efficiency. Traditional NTR designs use typically high power reactors with fast or epithermal neutron spectrums to simplify core design and to maximize thrust. In parallel there are a series of new NTR designs with lower thrust and higher efficiency, designed to enhance mission versatility and safety through the use of redundant engines (when used in a clustered engine arrangement) for future commercialization. This paper proposes a new NTR design of the second design philosophy, Korea Advanced NUclear Thermal Engine Rocket (KANUTER), for future space applications. The KANUTER consists of an Extremely High Temperature Gas cooled Reactor (EHTGR) utilizing hydrogen propellant, a propulsion system, and an optional electricity generation system to provide propulsion as well as electricity generation. The innovatively small engine has the characteristics of high efficiency, being compact and lightweight, and bimodal capability. The notable characteristics result from the moderated EHTGR design, uniquely utilizing the integrated fuel element with an ultra heat-resistant carbide fuel, an efficient metal hydride moderator, protectively cooling channels and an individual pressure tube in an all-in-one package. The EHTGR can be bimodally operated in a propulsion mode of $100MW_{th}$ and an electricity generation mode of $100MW_{th}$, equipped with a dynamic energy conversion system. To investigate the design features of the new reactor and to estimate referential engine performance, a preliminary design study in terms of neutronics and thermohydraulics was carried out. The result indicates that the innovative design has great potential for high propellant efficiency and thrust-to-weight of engine ratio, compared with the existing NTR designs. However, the build-up of fission products in fuel has a significant impact on the bimodal operation of the moderated reactor such as xenon-induced dead time. This issue can be overcome by building in excess reactivity and control margin for the reactor design.

• 제어로봇시스템학회논문지
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• 제11권12호
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• pp.984-990
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• 2005

The aim of this paper is to investigate a control framework for mobile robots, operating in shared environment with humans. The Intelligent Space (iSpace) can sense the whole space and evaluate the situations in the space by distributing sensors. The mobile agents serve the inhabitants in the space utilizes the evaluated information by iSpace. The iSpace evaluates the situations in the space and learns the walking behavior of the inhabitants. The human intelligence manifests in the space as a behavior, as a response to the situation in the space. The iSpace learns the behavior and applies to mobile agent motion planning and control. This paper introduces the application of fuzzy-neural network to describe the obstacle avoidance behavior teamed from humans. Simulation results are introduced to demonstrate the efficiency of this method.

• 대한교통학회지
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• 제5권1호
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• pp.75-83
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• 1987

The modernistic rationalism which thinks much of the mathematical rationality and economic efficiency is widely spread in Korea economic planning, urban planning, urban transportation planning, and the like. As a result the demands to humanity, amanity, and so on have been disregarded in the name of rationality in urban spatial organization, the typical examples, one of the pedestrian space. The pedestrian space which is passed over easily from the view point of the modernistic rationalism, is actually the space that should be reflected abundantly in urban space. The author emphasized a need of reconsideration on the position of pedestrian space in urban spatial planning process, and adopted the theoretical research on the functions and roles of pedestrian space. In consequence of this study the functions of pedestrian space are considered : the first, the function as a space for moving, the second, the function as a space for buffer. the third, the function as a space for intermediation. the fourth, the function as a space for urban daily life. the fifth, the function as new urban environment-making factor.

• 천문학회보
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• 제14권
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• pp.8.1-8.1
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• 1989

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.2292-2309
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• 2017

Ciphertext policy attribute-based encryption (CP-ABE) is a useful cryptographic technology for guaranteeing data confidentiality but also fine-grained access control. Typically, CP-ABE can be divided into two classes: small universe with polynomial attribute space and large universe with unbounded attribute space. Since the learning with errors over rings (R-LWE) assumption has characteristics of simple algebraic structure and simple calculations, based on R-LWE, we propose a small universe CP-ABE scheme to improve the efficiency of the scheme proposed by Zhang et al. (AsiaCCS 2012). On this basis, to achieve unbounded attribute space and improve the expression of attribute, we propose a large universe CP-ABE scheme with the help of a full-rank differences function. In this scheme, all polynomials in the R-LWE can be used as values of an attribute, and these values do not need to be enumerated at the setup phase. Different trapdoors are used to generate secret keys in the key generation and the security proof. Both proposed schemes are selectively secure in the standard model under R-LWE. Comparison with other schemes demonstrates that our schemes are simpler and more efficient. R-LWE can obtain greater efficiency, and unbounded attribute space means more flexibility, so our research is suitable in practices.