• 한국정보처리학회논문지
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• 제2권1호
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• pp.106-118
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• 1995

본 연구에서는 스케쥴링과 하드웨어 할당에 관련된 상위단계합성에서 최적설계 방법론을 효과적으로 변형된 시뮬레이티드 어닐링 기법을 사용하여 정립한다. 또한 정립된 기법을 디지탈필터(DF : digital filter)의 설계에 적용하여 파이프라인 DF 의 경우 최적설계시에 속도와 하드웨어의 최적의 절충 문제와 어레이 DF에서의 해석 에 관련된 문제점을 검토한다. 이러한 적용사례를 통해 제안된 방법이 보다 빠른 시간 에 향상된 비용함수값을 줄 수 있음이 확인되고 복잡한 디지탈필터 설계에 이용될 수 있음이 입증된다.

• 한국과학예술포럼
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• 제37권3호
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• pp.135-145
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• 2019

BIM기반 협업 과정에서 정보 교환을 위해 활용중인 IFC(Industry Foundation Classes)는 구조적인 한계로 분야간 정보 교환 결과에 대한 신뢰성을 확보하지 못하고 있다. 결국 분야별 전문 BIM 소프트웨어를 사용 할 수밖에 없는 현실적 문제로 정보 교환 및 변경 과정에서 원할한 상호 운영성을 확보 하지 못하고 있다. 본 연구는 이러한 문제들을 해결하기 위해 소프트웨어 개발사들이 제공하고 있는 오픈 소스(Open Source)를 활용하여 건축-구조 분야 간 BIM 업무 상호 운영성 확보 방안을 찾기 위해 다음과 같이 연구하였다. 첫째, 전문가 설문조사 및 심층 인터뷰를 통해 건축-구조 분야간 협업 과정에서 요구되어지는 정보들과 개선 요소를 도출하였다. 둘째, 개선 요소에 대한 해결 방안을 찾기 위해 Open-API 관련 기존 연구 고찰과 국·내외 API를 개발 사례를 조사 및 분석하였다. 셋째, 각 분야에서 주로 활용중인 BIM S/W를 중심으로 Open API를 활용하여 상호 운영성을 확보 할 수 있는 애드온(Add-On)을 개발하였다. 연구 결과 API를 활용하여 분야간 설계 변경 이력관리를 통한 상호 운영성을 확보 할 수 있는 가능성을 확인 하였다. 향후 시공 및 유지관리 분야까지 API 활용 범위는 넓어질 것으로 판단된다. 따라서 응용 확산을 위해 활용성을 높이기 위해서는 사용자 중심의 검증을 통한 인터페이스 개선에 대한 연구가 추가적으로 필요하다.

• 보존과학연구
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• 통권27호
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• pp.103-128
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• 2006

Rock properties of the five storied stone pagoda in the Mooryangsa temple are consist mainly in medium grained biotite granite with partly pegmatite veinlet. A part of the foundation stone is substituted in identical rock properties of the pagoda. The upper part of the pagoda is used purples and stone, gray shale and granodiorite. The most serious problem of the pagoda is structual instability from centered subsidence of the ground in northwestern direction remarkably. In southern view, the upper part of the pagoda also is slanted a little in right, it will need reinforcement by engineering method for structual stability of the stone pagoda. Weathering states of the stone pagoda are affected results of natural and artifical factors due to the surface-exfoliation, fine-fissure, crack, falling offs. On the rock surface of the pagoda, ferro-manganese hydroxide compounds are coated along the rainpathway. Also, bryophyte range concentration spreads raindrops face of roof rock properties, which areadd biological weathering effects. For the synthetic evaluation of the deterioration state, we make detailed surface weathering maps, it will be contribute to investigation for future conservation schemes.

• 한국전기전자재료학회논문지
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• 제37권4호
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• pp.420-426
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• 2024

This study proposes an innovative methodology for developing flexible printed circuit boards (FPCBs) capable of conforming to three-dimensional shapes, meeting the increasing demand for electronic circuits in diverse and complex product designs. By integrating a traditional flat plate-based fabrication process with a subsequent three-dimensional thermal deformation technique, we have successfully demonstrated an FPCB that maintains stable electrical characteristics despite significant shape deformations. Using a modified polyimide substrate along with Ag flake-based conductive ink, we identified optimized process variables that enable substrate thermal deformation at lower temperatures (~130℃) and enhance the stretchability of the conductive ink (ε ~30%). The application of this novel FPCB in a prototype 3D-shaped sensor device, incorporating photosensors and temperature sensors, illustrates its potential for creating multifunctional, shape-adaptable electronic devices. The sensor can detect external light sources and measure ambient temperature, demonstrating stable operation even after transitioning from a planar to a three-dimensional configuration. This research lays the foundation for next-generation FPCBs that can be seamlessly integrated into various products, ushering in a new era of electronic device design and functionality.

• Smart Structures and Systems
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• 제15권2호
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• pp.335-353
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• 2015

Previous long-term measurements of the Uldolmok tidal current power plant showed that the structure's natural frequencies fluctuate with a constant cycle-i.e., twice a day with changes in tidal height and tidal current velocity. This study aims to improve structural health monitoring (SHM) techniques for offshore structures under a harsh tidal environment like the Uldolmok Strait. In this study, lab-scale experiments on a simplified offshore structure as a lab-scale test structure were conducted in a circulating water channel to thoroughly investigate the causes of fluctuation of the natural frequencies and to validate the displacement estimation method using multimetric data fusion. To this end, the numerical study was additionally carried out on the simplified offshore structure with damage scenarios, and the corresponding change in the natural frequency was analyzed to support the experimental results. In conclusion, (1) the damage that occurred at the foundation resulted in a more significant change in natural frequencies compared with the effect of added mass; moreover, the structural system became nonlinear when the damage was severe; (2) the proposed damage index was able to indicate an approximate level of damage and the nonlinearity of the lab-scale test structure; (3) displacement estimation using data fusion was valid compared with the reference displacement using the vision-based method.

• Journal of Information Processing Systems
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• 제19권4호
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• pp.527-539
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• 2023

In the positioning algorithm of two-dimensional planar sensor array, the estimation error of time difference-ofarrival (TDOA) algorithm is difficult to avoid. Thus, how to achieve accurate positioning is a key problem of the positioning technology based on planar array. In this paper, a method of sensor reliability discrimination is proposed, which is the foundation for selecting positioning sensors with small error and excellent performance, simplifying algorithm, and improving positioning accuracy. Then, a positioning model is established. The estimation characteristics of the least square method are fully utilized to calculate and fuse the positioning results, and the non-uniform weighting method is used to correct the weighting factors. It effectively handles the decreased positioning accuracy due to measurement errors, and ensures that the algorithm performance is improved significantly. Finally, the characteristics of the improved algorithm are compared with those of other algorithms. The experiment data demonstrate that the algorithm is better than the standard least square method and can improve the positioning accuracy effectively, which is suitable for vibration detection with large noise interference.

• 대한조선학회논문집
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• 제52권4호
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• pp.315-322
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• 2015

In this paper, the theory of rectangular plate on the elastic foundation is used to get the relation equation between the effective Young’s modulus and the ice sheet deflection by applying the characteristic length concept, since the model ice sheet is rectangular shape in KRISO (Korea Research Institute for Ships and Ocean Engineering) ice basin. The obtained relation equation is equal to that of using the circular plate theory. A device is made and used to measure the deflection of ice plate using LVDT (Linear Variable Differential Transformer) for several loading cases and the procedure of experiments measuring the deflection used for getting the Young’s modulus is explained. In addition, the flexural strength value obtained through flexural strength experiments is compared with that of finite element analysis using the obtained effective Young’s modulus. Also, a nonlinear FEA (Finite Element Analysis) of cantilever ice beam is done with eroding effect and LS-DYNA result shows the fracture of brittle ice under 1 mm/s velocity load.

• 한국정보통신학회논문지
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• 제22권6호
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• pp.910-915
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• 2018

미국의 GPS, 러시아의 GLONASS, 유럽의 Galileo, 중국의 Beidou 등과 같은 GNSS(Global Navigation Satellite System)의 핵심요소인 정밀 시각은 전 세계에서 다양한 경제적 활동의 중요한 근간이 되어 있다. 통신시스템, 전력 그리드, 금융 네트워크 등은 기본적인 작동 원리의 근간뿐만 아니라 작업들 간의 동기와 운영적 효율을 위해 정밀 시각을 기반으로 동작한다. 본 논문에서는 GNSS 신호 관측을 통해 클럭의 오류(클럭 솔루션)를 계산하는 방법인 정밀 절대측위 기법을 구현한 벨기에의 아토미움을 국내에서 처음으로 소개하고 한국표준과학연구원 관측 데이터를 적용하여 클럭 솔루션을 추출한 결과를 제시한다.

• 기술혁신연구
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• 제31권3호
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• pp.111-138
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• 2023

본 논문의 목적은 주요 과학기술인력정책의 발전과정에 대한 정리와 함께 수급 패러다임 변화라는 정책 환경 속에서 바람직한 미래 정책 방향을 도출하는 데 있다. 이를 위해 먼저 이공계 기피 현상 해소를 화두로 2000년대부터 본격 추진되었던 과학기술인력정책의 전개과정을 이공계인력 지원 기본계획을 중심으로 살펴보았다. 다음으로 디지털 전환 등으로 인해 나타나는 과학기술인력 수요 변화와 인구구조 감소라는 공급충격, 즉 과학기술인재 수급 패러다임 전환의 주요 내용과 시사점을 정리하였다. 이를 바탕으로 미래 과학기술인력정책의 핵심 방향을 우수 과학기술인재 배출과 활용의 토대가 되어 인재의 지속 성장과 유입을 촉진시키는, 사람 중심의 과학기술 연구생태계 조성으로 제언하였다.

• 한국자동차공학회논문집
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• 제22권4호
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• pp.46-54
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• 2014

The hollow design of a railway axle is one of the most effective methods to reduce the weight of an axle. However, the conventional hollow axle has the limitation of a lightweight design because it has the same bore diameter along the axial position. The new type of railway axle, the tapered inner surface railway axle, has a different inner diameter between the journal bearing seat and wheel seat. This design method is one way to increase the weight reduction possibility. The purpose of the present study is to establish and evaluate the design of the tapered inner surface railway axle. The case study and Finite Element Method(FEM) are applied to evaluate the strength of the lightweight railway axle according to the European Norm(EN 13103). Finally, the best design case for reducing the weight of the axle is drawn from the results of the case study.