• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.1
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• pp.41-51
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• 2018

Format preserving encryption(FPE) performs encryption with preserving the size and format of plain-text. Therefore, it is possible to minimize the structural change of the database before and after the encryption. For example, when encrypting data such as credit card number or social security number, it is possible to maintain the existing database structure because FPE outputs the same form of cipher-text as plain-text. Currently, the National Institute of Standards and Technology (NIST) recommends FF1 and FF3 as standards for FPE. Recently, in Korea, FEA, which is a very efficient FPE algorithm, has been adopted as the standard of FPE. In this paper, we analyze FEA and measure the performance of FEA by optimizing it in various environments.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.4
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• pp.454-461
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• 2015

This study compares the results of a sled test and FEA(Finite Element Analysis) of a vehicle seatbelt system and aims to propose a method to efficiently reduce the error rate in the results of the FEA. This study evaluates the relative importance of potential causes, applying AHP(Analytic Hierarchy Process) technique in order to improve the reliability of the result of the FEA, and draw a highly reliable result of FEA, conducting a Taguchi Method and optimization for reducing the error rate in the FEA through the design of experiments.

• Korean Journal of Computational Design and Engineering
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• v.10 no.5
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• pp.328-338
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• 2005

CAD systems are routinely used by designers for creating part geometries. Interfaces to CAE/CAM systems are also commonplace enabling the FEA-based design optimization and the rapid fabrication of the designed part. However, conventional CAD systems have thus far focused on objects with homogeneous interior. Two recent advances--use of heterogeneous objects such as Functionally Graded Materials (FGM) in parts and Layered Manufacturing Technology (LMT)--have brought to the forefront the need for CAD systems to support the creation of geometry as well as the graded material inside. We first describe the need and the components of such a CAD system for heterogeneous objects. A prototype CAD system is then described with one specific example (thermal barrier type FGM, pressure vessel) in order to illustrate the use of the implemented CAD system. The implemented system is manually integrated with FEA tools for optimal design. Our ongoing work involves the automation of the integration with FEA tools.

• Korean Journal of Materials Research
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• v.8 no.1
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• pp.10-12
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• 1998

Si FEA 로부터 tip의 표면을 Ti금속으로 silicidation한 새로운 2극형 Ti-실리사이드 FEA를 제작하고 이의 전계방출 특성을 Si FEA의 경우와 비교하였다. 양극과 음극간의 거리를 10$\mu\textrm{m}$로 유지하고 $10^{-8}$Torr의 고진공 상태에서 측정한 실리사이드 FEA의 turn-on전압은 약 40V로, 전계방출전류와 정상상태 전류 변동율은 150V의 바이어스 아래에서 약 3x$10^{-2}$ $\mu$A/tip와 0.1%min로 나타났다. Ti-실리사이드 FEA는 Si FEA에 비해 낮은 turn-on 전압, 높은 전계방출전류 및 고내구특성을 나타내었다.

• Steel and Composite Structures
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• v.18 no.1
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• pp.213-233
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• 2015

A nonlinear finite element analysis (FEA) model is presented for simulating the behaviour of recycled aggregate concrete-filled steel tube (RACFST) beam-columns subjected to constant axial compressive load and cyclically increasing flexural loading. The FEA model was developed based on ABAQUS software package and a displacement-based approach was used. The proposed engineering stress versus engineering strain relationship of core concrete with the effect of recycled coarse aggregate (RCA) replacement ratio was adopted in the FEA model. The predicted results of the FEA model were compared with the experimental results of several RACFST as well as the corresponding concrete-filled steel tube (CFST) beam-columns under cyclic loading reported in the literature. The comparison results indicated that the proposed FEA model was capable of predicting the load versus deformation relationship, lateral bearing capacity and failure pattern of RACFST beam-columns with an acceptable accuracy. A parametric study was further carried out to investigate the effect of typical parameters on the mechanism of RACFST beam-columns subjected to cyclic loading.

• Journal of the Korea Safety Management & Science
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• v.9 no.2
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• pp.135-147
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• 2007

이 논문은 CC 프로세스의 movable side trowel 효과를 연구하기 위한 실험과 모델링을 제시한다. FEA simulation을 이용하여 우리는 movable side trowel의 효과와 움직임에 대한 기초적인 이해를 얻어냈다. 단면의 side trowel 보다 양면의 side trowel이 실제의 3D 형상을 만드는 동안에 층간의 최적의 결합을 만들어 준다는 면에서 가장 적합하다는 것을 알아냈다. 우리의 실험이 위의 결과를 입증하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.3
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• pp.223-233
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• 2011

A ceramic monolithic catalyst is a honeycomb structure that consists of two layers. The honeycomb structure is regarded as a continuum in structure and heat-flow analysis. The equivalent mechanical properties of the honeycomb structure were determined by performing finite element analysis (FEA) for a test specimen. Bending strength experiments and FEA of the test specimen used in ASTM C1674-08 standard test were performed individually. The bonding coefficient between the cordierite ceramic layer and the washcoat layer was almost zero. The FEA test specimen was modeled on the basis of the bonding coefficient. The elastic modulus, Poisson's ratio, and the thermal properties of the ceramic monolithic substrate were determined by performing the FEA of the test specimen.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.216-220
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• 2000

AC Superconducting Generators (ACSG) are featured by 3D magnetic flux distribution, which decreases in the direction of axis. For this reason, when ACSG is optimal designed, 3D magnetic field analysis is required. This paper proposes 2D Finite Element Analysis (FEA) results normalized by 3D FEA according to the position of armature coil and the ratio of field coil width to axial length in order to reduce the analysis time. By using the proposed data, the reasonable 3D FEA results of ACSG can be only predicted by 2D FEA results. The validity of the 3D FEA results is verified by comparison with the experimental results of 30kVA superconducting synchronous generator.

• Proceedings of the Korean Society For Composite Materials Conference
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• pp.43-47
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• 1999

A FEA model is proposed to study the effects of fiber waviness on tensile/comprssive nonlinear behaviors of thick unidirectional composites. In the analyses both material and geometical nonlinarities are considered. The predicted results from the FEA model are compared with those obtained from the previous analytical model (thin carpet model) Tensile/compressive tests are also conducted on the specimens with various controlled fiber waviness to obtain the nonlinear behaviors of composites experimentally. The predictions from the FEA model show better agreements with the experiments than those from the analytical model.

• Proceedings of the KIEE Conference
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• pp.836-837
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• 2008

현재 화석에너지 고갈에 따른 다양한 신재생에너지의 활용에 대한 연구가 활발히 진행되고 있다. 본 논문은 영구자석을 사용한 수력용 영구자석 다극형 동기발전기의 기동토크 저감을 위한 최적설계 방안에 대해 연구를 수행하였다. 먼저 FEA 해석기법을 이용한 수력용 영구자석 다극형 동기발전기의 설계 및 발전기 기동토크에 가장 큰 영향을 주는 코깅토크 저감 방안에 대해 연구하였다. 코깅토크 저감을 위해 고정자 skew비에 따른 코깅토크의 변화를 FEA해석기법을 통해 알아보았으며, 실제 고정자에 skew를 적용하였을 때, 코깅토크의 최소화에 가장 적합함을 알 수 있었다. 또한 실제 설계된 영구자석 다극형 동발전기의 출력 및 코깅토크 측정 결과와 FEA해석결과를 비교 및 분석하여 FEA해석방법의 타당성을 입증하였다.