• 한국항공우주학회지
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• 제41권6호
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• pp.488-494
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• 2013

전자식 비행제어시스템(Fly-By-Wire Flight Control System)에 적용되는 헬리콥터의 제어법칙 설계 및 해석은 모델기반 설계기법(Model Based Design)을 사용하여 개발되고 있다. 모델기반 설계기법은 회전익뿐만 아니라 고정익, 무인항공기, 자동차 산업에서도 널리 사용되고 있다. 모델기반 설계기법은 핵심기술인 시뮬레이션과 자동생성코드를 이용하여 개발기간 단축 및 개발리스크 감소라는 장점을 제공한다. 본 논문에서는 FBW 헬리콥터 비행제어법칙의 자동생성코드에 대해서 체계적인 기능검증을 위한 프로세스를 개발하였다. 그리고 지식경제부 과제로 진행하고 있는 FBW 헬리콥터 개발에 적용하여 비행제어법칙 자동생성코드의 기능 검증을 수행 결과, 요구 조건을 충족하는 것으로 확인할 수 있었다.

• 한국CDE학회논문집
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• 제21권4호
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• pp.433-442
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• 2016

This paper aims to define the relational logic of in-between code articles as well as within atomic sentences in Korean Building Code, as an intermediate research and development process for the automated building permit system of Korea. The approach depicted in this paper enables the software developers to figure out the logical relations in order to compose KBimCode and its databases. KBimCode is a computer-readable form of Korean Building Code sentences based on a logic rule-based mechanism. Two types of relational logic definition are described in this paper. First type is a logic definition of relation between code sentences. Due to the complexity of Korean Building code structure that consists of decree, regulation or ordinance, an intensive analysis of sentence relations has been performed. Code sentences have a relation based on delegation or reference each other. Another type is a relational logic definition in a code sentence based on translated atomic sentence(TAS) which is an explicit form of atomic sentence(AS). The analysis has been performed because the natural language has intrinsic ambiguity which hinders interpreting embedded meaning of Building Code. Thus, both analyses have been conducted for capturing accurate meaning of building permit-related requirements as a part of the logic rule-based mechanism.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.501-504
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• 2000

In this paper, performance of a pseudonoise (PN) code tracking loop is analyzed and simulated for a direct-sequence/code-division multiple access ( DS/CDMA) system with imperfect power control in a multipath fading channel. A noncoherent first-order delay-locked loop (DLL) is considered as a PN code tracking loop. Power control error is modeled as a log-normally distributed random variable. From the simulation results, it is shown that for smaller discriminator offset, tracking jitter performance is improved while MTLL performance is degraded. It is shown that large power control error and heavy shadowing substantially degrade the PN tracking performance. The analysis in this paper can be applicable to design of PN code tracking loop for a DS/CDMA system.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4280-4295
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• 2022

In this paper, a new multi-group neutron-gamma transport calculation code system STRAUM-MATXST for complicated geometrical problems is introduced and its development status including numerical tests is presented. In this code system, the MATXST (MATXS-based Cross Section Processor for S_N Transport) code generates multi-group neutron and gamma cross sections by processing MATXS format libraries generated using NJOY and the STRAUM (S_N Transport for Radiation Analysis with Unstructured Meshes) code performs multi-group neutron-gamma coupled transport calculation using tetrahedral meshes. In particular, this work presents the recent implementation and its test results of the Krylov subspace methods (i.e., Bi-CGSTAB and GMRES(m)) with preconditioners using DSA (Diffusion Synthetic Acceleration) and TSA (Transport Synthetic Acceleration). In addition, the Krylov subspace methods for accelerating the energy-group coupling iteration through thermal up-scatterings are implemented with new multi-group block DSA and TSA preconditioners in STRAUM.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2004년도 춘계학술대회 논문집
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• pp.101-108
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• 2004

KEPRI has developed an Nuclear Steam Supply System(NSSS) thermal-hydraulics simulation program (called ARTS-KORI), based on the best-estimate system code, RETRAN, as a part of the development project for the KORI unit 1 Nuclear Power Plant Simulator. A number of code modifications, such as simplifications and removing of discontinuities of the physical correlations, were made in order to change the RETRAN code as an nuclear Steam Supply System thermal-hydraulics engine in the simulator. Some simplified models and a backup system were also developed. This paper briefly presents the results of non-integrated standalone test of ARTS-KORI.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(1)
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• pp.209-212
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• 2000

In this paper, effect of imperfect power control on performance of a pseudonoise (PN) code tracking loop is analyzed and simulated for a direct-sequence/code-division multiple access (DS/CDMA) system. The multipath fading channel is modeled as a two-ray Rayleigh fading model. Power control error is modeled as a log-normally distributed random variable. The tracking performance of DLL (delay-locked-loop) is evaluated in terms of tracking jitter and mean-time-to-lose-lock (MTLL). From the simulation results, it is shown that the PN tracking performance is very sensitive to the power control error.

• 인터넷정보학회논문지
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• 제7권4호
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• pp.11-22
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• 2006

소프트웨어 프러덕트 라인 개발 방법론이란, 개발 초기에 시스템의 공통적인 부분과 가변적인 부분을 명확히 하여 소프트웨어 자산을 구축한 후 요구 사항에 따라 가변적인 부분을 커스터마이징하여 목표 시스템을 생성하는 소프트웨어 개발 패러다임이다. 일반적인 소프트웨어 프러덕트 라인에 대한 연구는 활발히 진행되고 있지만, 컴포넌트 기반의 실시간 임베디드 소프트웨어 프러덕트 라인에 대한 연구는 상대적으로 미약하다. 본 논문에서는 실시간 임베디드 소프트웨어 프러덕트 라인구축의 생산성 향상을 위해, 특성 모델을 통해 기능적 가변성을 지원하고 상태 모델을 통해 동기화 지원 코드를 생성하는 코드 생성 시스템을 제안한다.

• Nuclear Engineering and Technology
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• 제43권1호
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• pp.45-62
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• 2011

The Korean nuclear industry is developing a thermal-hydraulic analysis code for safety analysis of pressurized water reactors (PWRs). The new code is called the Safety and Performance Analysis Code for Nuclear Power Plants (SPACE). The SPACE code adopts advanced physical modeling of two-phase flows, mainly two-fluid three-field models which comprise gas, continuous liquid, and droplet fields and has the capability to simulate 3D effects by the use of structured and/or nonstructured meshes. The programming language for the SPACE code is C++ for object-oriented code architecture. The SPACE code will replace outdated vendor supplied codes and will be used for the safety analysis of operating PWRs and the design of advanced reactors. This paper describes the overall features of the SPACE code and shows the code assessment results for several conceptual and separate effect test problems.

• Nuclear Engineering and Technology
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• 제43권6호
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• pp.489-498
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• 2011

UK National Nuclear Laboratory's (NNL's) version of the ENIGMA fuel performance code is described, including details of the development history, the system modelled, the key assumptions, the thermo-mechanical solution scheme, and the various incorporated models. The recent development of ENIGMA in the areas of whole core analysis and dry storage applications is then discussed. With respect to the former, the NEXUS code has been developed by NNL to automate whole core fuel performance modelling for an LWR core, using ENIGMA as the underlying fuel performance engine. NEXUS runs on NNL's GEMSTONE high performance computing cluster and utilises 3-D core power distribution data obtained from the output of Studsvik Scandpower's SIMULATE code. With respect to the latter, ENIGMA has been developed such that it can model the thermo-mechanical behaviour of a given LWR fuel rod during irradiation, pond cooling, drying, and dry storage - this involved: (a) incorporating an out-of-pile clad creep model for irradiated Zircaloy-4; (b) including the ability to simulate annealing out of the clad irradiation damage; (c) writing of additional post-irradiation output; (d) several other minor modifications to allow modelling of post-irradiation conditions.

• 한국산학기술학회논문지
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• 제19권10호
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• pp.167-175
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• 2018

최근 증가하고 있는 자연재해에 효과적으로 대처하기 위해서는 그간 다양하고 풍부한 경험을 지닌 재난상황관리 담당자들의 역할이 대단히 중요하다. 중앙재난안전상황실에서는 각종 자연 및 사회재난에 대비하여 재난상황관리 업무를 하고 있으나, 담당자의 잦은 교체로 과거 데이터가 남아 있지 않다. 이에 본 연구에서는 재난관련 기록관리 및 정보 공유가 저조함에 따라 재난정보를 추적하고 관리하기 위한 체계를 마련하기 위하여 재난안전 코드체계를 개발하였다. 22개 자연재난과 사회재난 중에서 대설, 강풍, 풍랑, 호우 등 4개 재난을 대상으로 하였다. 국내외 재난분야 코드체계 사례분석, 구축방향설정, 분류체계 개발 및 유형화 과정을 통해 최종 재난안전 데이터 코드체계를 제시하였다. 데이터의 체계적인 축적을 위하여 4개의 코드체계를 하나로 통합하였다. 제시한 코드체계의 적정성을 검증하기 위하여 운용가능한 프로토타입 시스템을 개발하여 운용한 결과, 코드체계에 맞게 데이터가 축적되고 서비스되는 것으로 확인되었다. 본 연구에서 제시한 코드체계에 따라 과거의 많은 데이터가 축적되어 활용된다면 과거 경험을 바탕으로 새로운 재난에 대응하기 위한 의사결정에 도움을 줄 것으로 생각된다.