• Nuclear Engineering and Technology
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• 제48권5호
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• pp.1126-1139
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• 2016

In this research, for the first time, a new optimization method, i.e., strength Pareto evolutionary algorithm II (SPEA-II), is developed for the burnable poison placement (BPP) optimization of a nuclear reactor core. In the BPP problem, an optimized placement map of fuel assemblies with burnable poison is searched for a given core loading pattern according to defined objectives. In this work, SPEA-II coupled with a nodal expansion code is used for solving the BPP problem of Kraftwerk Union AG (KWU) pressurized water reactor. Our optimization goal for the BPP is to achieve a greater multiplication factor ($K_{eff}$) for gaining possible longer operation cycles along with more flattening of fuel assembly relative power distribution, considering a safety constraint on the radial power peaking factor. For appraising the proposed methodology, the basic approach, i.e., SPEA, is also developed in order to compare obtained results. In general, results reveal the acceptance performance and high strength of SPEA, particularly its new version, i.e., SPEA-II, in achieving a semioptimized loading pattern for the BPP optimization of KWU pressurized water reactor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.598-600
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• 2002

The magnet design is investigated by using the topology optimization and FEM. The design sensitivity equation for topology optimization is derived using the adjoint variable method and the continuum approach. The proposed method is applied to the topology optimization of C-core.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.726-728
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• 2002

The topology optimization of electromagnetic systems with two materials is investigated using the FEM. The design sensitivity equation for topology optimization is derived using the adjoint variable method and the continuum approach. The proposed method is applied to the topology optimization of C-core and compared to previous study with one material.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.479-484
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• 2000

The topology optimization of electromagnetic systems is investigated and the TOPEM (Topology Optimization for Electromagnetic Systems) is developed using the finite element method (FEM). The design sensitivity equation for topology optimization is derived using the adjoint variable method. The proposed method is validated by applying it to the topology optimizations of a C-core actuator and an optical pickup actuator.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.705-707
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• 2003

The design of multi-domain that considers all components of the electromagnetic systems such as air, iron, magnet, and coil is investigated using the topology optimization, interpolation method, and FEM. The design sensitivity equation for the topology optimization is derived using the adjoint variable method and the continuum approach. The proposed method is applied to the topology optimization of C-core actuator.

• 대한전자공학회논문지SD
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• 제45권4호
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• pp.117-123
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• 2008

본 논문에서는 규칙적인 형태의 NoC 중 mesh 구조를 기반으로 한 어플리케이션 코어 매핑 알고리즘 연구 내용을 소개한다. 제안된 알고리즘은 ant colony optimization(ACO) 기법을 이용하여 주어진 SoC 내장 코어 및 NoC 특성 정보를 대상으로 가장 효과적인 코어 배치 결과를 도출한다. 설계 목적으로 사용된 네트워크 지연 시간 측정을 위해 평균 흡수 계산 결과를 이용하였으며 제한 조건으로는 NoC 대역폭을 기준으로 하였다. 12개의 코어로 구성되는 실제 기능 블럭을 대상으로 실험한 결과 계산 시간이나 매핑 결과 모두 우수함을 확인할 수 있었다.

• 한국전자거래학회지
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• 제23권1호
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• pp.37-45
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• 2018

현재 프로그램이 운용되는 시스템은 기존의 싱글코어 및 멀티코어 환경을 넘어서 매니코어, 부가 프로세스 및 이기종 환경까지 그 영역이 확장되고 있는 중이다. 하지만, 기존 연구의 경우 NVIDIA 벤더에서 나온 아키텍쳐 및 CUDA로의 병렬화가 주로 이루어졌고 AMD에서 나온 범용 GPU 아키텍쳐인 GCN 아키텍쳐에 대한 성능향상에 관한 연구는 제한적으로 이루어졌다. 이런 점을 고려해 본 논문에서는 GCN 아키텍쳐의 GPGPU 환경인 OpenCL 내에서의 성능향상 기법에 대해 연구하고 실질적인 성능향상을 보였다. 구체적으로, 행렬 곱셈과 컨볼루션을 적용한 GPGPU 프로그램을 본 논문에서 제시한 성능향상 기법을 통해 최대 30% 이상의 실행시간을 감소시켰으며, 커널 이용률 또한 40% 이상 높였다.

• 조명전기설비학회논문지
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• 제28권11호
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• pp.58-67
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• 2014

A grid-connected inverter used for renewable energy resources produces harmonic components in the switching frequency. To effectively reduce switching harmonic components, several types of filter are generally used in the output stage of the grid-connected inverter. Many research works on LCL filter design have been done to maintain the performance with low cost. However, it is not easy to make the filter design be economical and optimal due to the varying characteristic of magnetic core and redundancy design by experience. In this paper, a design method for a LCL filter is presented through the inductor optimization scheme in view of the size and cost when the inductor is manufactured using the magnetic core. The effectiveness is verified through tests using a 3kW grid-connected inverter by simulations and experiments.

• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1687-1697
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• 2024

This study presents the Supporting platform for reactor fine flow characteristics calculation and analysis (Cilian platform), a user-friendly tool that supports the analysis and optimization of pressurized water reactor (PWR) cores with mixing vanes using computational fluid dynamics (CFD) computing. The Cilian platform allows for easy creation and optimization of PWR's main CFD calculation schemes and autonomously manages CFD calculation and analysis of PWR cores, reducing the need for human and computational resources. The platform's key features enable efficient simulation, rapid solution design, automatic calculation of core scheme options, and streamlined data extraction and processing techniques. The Cilian platform's capability to call external CFD software reduces the development time and cost while improving the accuracy and reliability of the results. In conclusion, the Cilian platform exemplifies an innovative solution for efficient computational fluid dynamics analysis of pressurized water reactor (PWR) cores. It holds great promise for driving advancements in nuclear power technology, enhancing the safety, efficiency, and cost-effectiveness of nuclear reactors. The platform adopts a modular design methodology, enabling the swift and accurate computation and analysis of diverse flow regions within core components. This design approach facilitates the seamless integration of multiple computational modules across various reactor types, providing a high degree of flexibility and reusability.

• 대한전자공학회논문지SP
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• 제46권3호
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• pp.119-124
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• 2009

본 논문에서는 AMR Core(R)를 이용해서 AMR-WB+ 오디오 부호화기를 실시간 구현하였다. 구현 시 사용된 최적화 방법은 어셈블리어 단계에서 수행되었고, latency를 제거하고 32비트 레지스터를 사용하였다. 구현된 음성 부호화기는 평균 복잡도가 ARM9E 버전에서 인코더 160.76MHz, 디코더 33.05MHz으로 총 193.81MHz로 측정되었다. 사용된 ROM의 크기는 인코더 65.21Kbyte, 디코더 32.01Kbyte, 공통소스 279.81Kbyte이다. 구현된 AMR-WB+ 소스 코드는 3GPP에서 제공하는 테스트 벡터들을 CodeWarrior와 목표 PDA 상에서 모두 bit-exact하게 통과함을 보임으로써 검증되었다.