• 한국정보과학회논문지:시스템및이론
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• 제28권11호
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• pp.601-612
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• 2001

슈퍼스칼라 프로세서에서 값 예측(value prediction)은 한 명령의 결과를 미리 예측하여 명령들 간의 데이터 종속관계를 극복하고 실행함으로써 명령어 수준 병렬성(Instruction Level Parallesim, ILP)을 이용하는 기법이다. 값 예측기(value predictor)는 명령어 페치 시에 예측 테이블을 참조(lookup)하여 값을 예측하고, 명령의 실행 후 판명된 예측 결과에 따라 테이블을 갱신(update)하여 이 후의 참조를 대비한다. 그러나, 최근의 값 예측기는 프로세서의 명령 페치 및 이슈율이 커짐에 따라 예측 테이블이 갱신되기 전에 다시 같은 명령이 페치되어 갱신되지 못한 낡은 값(stale value)으로 예측되는 경우가 빈번히 발생하여 예측기의 성능이 저하되는 경향이 있다. 본 논문에서는 이러한 성능저하를 줄이기 위해 명령의 결과가 나올 때가지 기다리지 않고 테이블 값을 모험적으로 갱신(speculative update)하는 스트라이트 값 예측기(stride value predictor)를 제안한다. 제안된 방식의 타당성을 검증하기 위해 SimpleScalar 시뮬레이터 상에 제안된 예측기를 구현하여 SPECint95 벤치마크를 시뮬레이션하고 제안된 모험적 갱신의 스트라이드 예측기가 기존의 스트라이드 예측기 보다 성능이 향상됨을 보인다.

• Advances in nano research
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• 제8권1호
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• pp.83-94
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• 2020

An analytical formulation and solution process for the buckling analysis of porous magneto-electro-elastic functionally graded (MEE-FG) beam via different thermal loadings and various boundary conditions is suggested in this paper. Magneto electro mechanical coupling properties of FGM beam are taken to vary via the thickness direction of beam. The rule of power-law is changed to consider inclusion of porosity according to even and uneven distribution. Pores possibly occur inside FGMs due the result of technical problems that lead to creation of micro-voids in these materials. Change in pores along the thickness direction stimulates the mechanical and physical properties. Four-variable tangential-exponential refined theory is employed to derive the governing equations and boundary conditions of porous FGM beam under magneto-electrical field via Hamilton's principle. An analytical model procedure is adopted to achieve the non-dimensional buckling load of porous FG beam exposed to magneto-electrical field with various boundary conditions. In order to evaluate the influence of thermal loadings, material graduation exponent, coefficient of porosity, porosity distribution, magnetic potential, electric voltage and boundary conditions on the critical buckling temperature of the beam made of magneto electro elastic FG materials with porosities a parametric study is presented. It is concluded that these parameters play remarkable roles on the buckling behavior of porous MEE-FG beam. The results for simpler states are proved for exactness with known data in the literature. The proposed numerical results can serve as benchmarks for future analyses of MEE-FG beam with porosity phases.

• Structural Engineering and Mechanics
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• 제72권1호
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• pp.113-129
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• 2019

A four-variable shear deformation refined plate theory has been proposed for dynamic characteristics of smart plates made of porous magneto-electro-elastic functionally graded (MEE-FG) materials with various boundary conditions by using an analytical method. Magneto-electro-elastic properties of FGM plate are supposed to vary through the thickness direction and are estimated through the modified power-law rule in which the porosities with even and uneven type are approximated. Pores possibly occur inside functionally graded materials (FGMs) due the result of technical problems that lead to creation of micro-voids in these materials. The variation of pores along the thickness direction influences the mechanical properties. The governing differential equations and boundary conditions of embedded porous FGM plate under magneto-electrical field are derived through Hamilton's principle based on a four-variable tangential-exponential refined theory which avoids the use of shear correction factors. An analytical solution procedure is used to achieve the natural frequencies of embedded porous FG plate supposed to magneto-electrical field with various boundary condition. A parametric study is led to carry out the effects of material graduation exponent, coefficient of porosity, magnetic potential, electric voltage, elastic foundation parameters, various boundary conditions and plate side-to-thickness ratio on natural frequencies of the porous MEE-FG plate. It is concluded that these parameters play significant roles on the dynamic behavior of porous MEE-FG plates. Presented numerical results can serve as benchmarks for future analyses of MEE-FG plates with porosity phases.

• 한국기록관리학회지
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• 제7권2호
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• pp.73-94
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• 2007

기록관은 이용자의 다양한 요구에 따라 변화하여 왔다. 초창기 기록관에서의 업무 수행은 자료의 수집 및 보존에 치중되었지만, 지금은 자료의 보존 뿐 아니라 활용에 대하여 많은 관심을 갖고 있다. 따라서 기록관들은 이용자 중심의 적극적 서비스를 제공하기 위하여 많은 노력을 기울이고 있다. 본 연구에서는 중앙기록물 관리기관인 국가기록원에서 2005년 서비스혁신팀을 신설하여 지난 2년간 수행한 각종 서비스 프로그램을 소개하고 이와 병행하여 선진기록국인 미국립기록관리청, 영국 기록관리청에서 수행하는 기록정보 서비스 내용을 소개하여 향후 벤치마킹을 할 수 있도록 하였다. 아울러 새로운 이용자를 창출하기 위한 서비스 프로그램 영역의 확대와 기록홍보의 중요성을 제언하면서 선진기록관의 기록정보 서비스 표준지침을 수록하여 국내 기록관련 유관기관의 향후 기록정보 서비스 정책을 수립하는데 기초 자료로 제시하였다.

• Advances in nano research
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• 제5권4호
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• pp.281-301
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• 2017

In this disquisition, an exact solution method is developed for analyzing the vibration characteristics of magneto-electro-elastic functionally graded (MEE-FG) beams by considering porosity distribution and various boundary conditions via a four-variable shear deformation refined beam theory for the first time. Magneto-electroelastic properties of porous FG beam are supposed to vary through the thickness direction and are modeled via modified power-law rule which is formulated using the concept of even and uneven porosity distributions. Porosities possibly occurring inside functionally graded materials (FGMs) during fabrication because of technical problem that lead to creation micro-voids in FG materials. So, it is necessary to consider the effect of porosities on the vibration behavior of MEE-FG beam in the present study. The governing differential equations and related boundary conditions of porous MEE-FG beam subjected to physical field are derived by Hamilton's principle based on a four-variable tangential-exponential refined theory which avoids the use of shear correction factor. An analytical solution procedure is used to achieve the natural frequencies of porous-FG beam supposed to magneto-electrical field which satisfies various boundary conditions. A parametric study is led to carry out the effects of material graduation exponent, porosity parameter, external magnetic potential, external electric voltage, slenderness ratio and various boundary conditions on dimensionless frequencies of porous MEE-FG beam. It is concluded that these parameters play noticeable roles on the vibration behavior of MEE-FG beam with porosities. Presented numerical results can be applied as benchmarks for future design of MEE-FG structures with porosity phases.

• Nuclear Engineering and Technology
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• 제53권1호
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• pp.44-60
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• 2021

In this paper, we validate the decay heat calculation capability via a two-step method to analyze spent nuclear fuel (SNF) discharged from pressurized water reactors (PWRs). The calculation method is implemented with a lattice code STREAM and a nodal diffusion code RAST-K. One of the features of this method is the direct consideration of three-dimensional (3D) core simulation conditions with the advantage of a short simulation time. Other features include the prediction of the isotope inventory by Lagrange non-linear interpolation and the use of power history correction factors. The validation is performed with 58 decay heat measurements of 48 fuel assemblies (FAs) discharged from five PWRs operated in Sweden and the United States. These realistic benchmarks cover the discharge burnup range up to 51 GWd/MTU, 23.2 years of cooling time, and spanning an initial uranium enrichment range of 2.100-4.005 wt percent. The SNF analysis capability of STREAM is also employed in the code-to-code comparison. Compared to the measurements, the validation results of the FA calculation with RAST-K are within ±4%, and the pin-wise results are within ±4.3%. This paper successfully demonstrates that the developed decay heat calculation method can perform SNF back-end cycle analyses.

• 한국인터넷방송통신학회논문지
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• 제21권2호
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• pp.27-32
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• 2021

본 논문은 차세대 사물인터넷 디바이스를 위한 에너지 효율적인 캐시 및 메모리 관리 기법을 제안한다. 제안하는 기법은 전력 소모가 적은 상변화 메모리를 사물인터넷 디바이스의 메인 메모리로 채택하고 캐시 메모리의 관리 시 쓰기 연산에 취약한 상변화 메모리의 쓰기량을 최소화하는 방향으로 설계한다. 구체적으로 살펴보면 최종단 캐시 메모리에서 캐시 블록이 삭제되어 메인 메모리로 반영될 때, 캐시 블록을 구성하는 캐시 라인별 수정 여부를 추적하여 상변화 메모리에 쓰기 발생량을 적게 발생시키는 캐시 블록을 우선적으로 교체한다. 또한, 최종단 캐시 메모리에서 캐시 블록의 참조 비트와 캐시 라인의 수정 비트를 함께 고려함으로써 메모리 시스템의 성능은 훼손하지 않으면서 에너지 소모를 줄이는 방식을 사용한다. 스펙 벤치마크를 이용한 시뮬레이션 실험을 통해 제안한 기법이 상변화 메모리에 발생하는 쓰기량을 평균 34.6% 줄이고 전력 소모를 28.9% 줄이면서 메모리의 성능 저하는 발생시키지 않음을 보인다.

• 한국컴퓨터정보학회논문지
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• 제26권11호
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• pp.11-19
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• 2021

본 논문은 충전식 배터리의 단점을 보완하여 급속 충전과 방전이 가능하고 높은 전력 효율 및 반영구적인 충·방전 사이클 수명의 특성을 갖는 수퍼커패시터를 보조 전력 저장장치로 사용하여 전력 관리 시스템에 결합한 프로토타입 플랫폼을 제안한다. 본 논문의 플랫폼을 위해 물리적인 환경 변화에 따른 태양광 패널에서의 공급 전력 차단 혹은 재개 상태를 마이크로컨트롤러에 연결된 인터럽트를 통해 감지할 수 있는 기법을 개발하였다. 연속적인 전원 공급이 보장되지 않는 컴퓨팅 환경에서 데이터의 유실을 방지하기 위해 전원 공급이 차단되는 경우 휘발성 메모리에 있는 프로그램 문맥 및 데이터를 비휘발성 메모리로 이전하는 낮은 수준의 시스템 소프트웨어를 마이크로컨트롤러에 구현하였다. 실험을 통해 슈퍼커패시터가 보조 전력 저장장치로서 일시적 전원 공급에 효과적으로 하는지를 검증하였으며 다양한 벤치마크를 통해 전원 상태 감지 및 휘발성 메모리에서 비휘발성 메모리로의 프로그램 문맥 및 데이터의 이전 기법이 낮은 오버헤드를 갖음을 확인하였다.

• Advances in nano research
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• 제7권4호
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• pp.249-263
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• 2019

In the current paper, an exact solution method is carried out for analyzing the thermo-mechanical vibration of curved FG nano-beams subjected to uniform thermal environmental conditions, by considering porosity distribution via nonlocal strain gradient beam theory for the first time. Nonlocal strain gradient elasticity theory is adopted to consider the size effects in which the stress for not only the nonlocal stress field but also the strain gradients stress field is considered. It is perceived that during manufacturing of functionally graded materials (FGMs) porosities and micro-voids can be occurred inside the material. Material properties of curved porous FG nanobeam are assumed to be temperature-dependent and are supposed to vary through the thickness direction of beam which modeled via modified power-law rule. Since variation of pores along the thickness direction influences the mechanical and physical properties, porosity play a key role in the mechanical response of curved FG nano-structures. The governing equations and related boundary condition of curved porous FG nanobeam under temperature field are derived via the energy method based on Timoshenko beam theory. An analytical Navier solution procedure is utilized to achieve the natural frequencies of porous FG curved nanobeam supposed to thermal loading. The results for simpler states are confirmed with known data in the literature. The effects of various parameters such as nonlocality parameter, porosity volume fractions, thermal effect, gradient index, opening angle and aspect ratio on the natural frequency of curved FG porous nanobeam are successfully discussed. It is concluded that these parameters play key roles on the dynamic behavior of porous FG curved nanobeam. Presented numerical results can serve as benchmarks for future analyses of curve FG nanobeam with porosity phases.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권2호
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• pp.751-770
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• 2019

Action recognition is an essential task in computer vision due to the variety of prospective applications, such as security surveillance, machine learning, and human-computer interaction. The availability of more video data than ever before and the lofty performance of deep convolutional neural networks also make it essential for action recognition in video. Unfortunately, limited crafted video features and the scarcity of benchmark datasets make it challenging to address the multi-person action recognition task in video data. In this work, we propose a deep convolutional neural network-based Effective Hybrid Learning (EHL) framework for two-person interaction classification in video data. Our approach exploits a pre-trained network model (the VGG16 from the University of Oxford Visual Geometry Group) and extends the Faster R-CNN (region-based convolutional neural network a state-of-the-art detector for image classification). We broaden a semi-supervised learning method combined with an active learning method to improve overall performance. Numerous types of two-person interactions exist in the real world, which makes this a challenging task. In our experiment, we consider a limited number of actions, such as hugging, fighting, linking arms, talking, and kidnapping in two environment such simple and complex. We show that our trained model with an active semi-supervised learning architecture gradually improves the performance. In a simple environment using an Intelligent Technology Laboratory (ITLab) dataset from Inha University, performance increased to 95.6% accuracy, and in a complex environment, performance reached 81% accuracy. Our method reduces data-labeling time, compared to supervised learning methods, for the ITLab dataset. We also conduct extensive experiment on Human Action Recognition benchmarks such as UT-Interaction dataset, HMDB51 dataset and obtain better performance than state-of-the-art approaches.