• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.957-960
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• 2009

최근 대용량 데이터 저장을 위한 스토리지에 대한 요구가 증가되고 있다. 이들 대용량 스토리지 시스템은 다양한 형상으로 구성될 수 있으며 학교, 기업 및 정부기관에서는 스토리지 성능은 기업 내부 전체 정보 시스템의 성능을 결정하는 주요한 요소로서 영향을 미친다. 그러나 성능시험을 위한 이형의 환경과 시험을 위한 성능 파라매터가 상이함으로 인해 스토리지 벤더에서는 제공하는 결과에 대한 평가가 쉽지 않다. 이 논문에서는 스토리지 성능시험 기법과 벤치마킹을 위한 성능시험환경을 제안한다. 성능시험 환경은 NGS 시스템 아키텍처 내의 병목 현상을 제거하고 입출력 대역폭을 늘려 성능을 최적화에 활용할 수 있다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.500-503
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• 2010

본 논문에서는 산업용 용접구조물의 피로성능 평가를 위한 시간 및 비용 절감형 전산피로시험법을 개발한다. 임의의 하중에 놓인 용접구조물의 성능저하 현상(균열발생 및 진전 등)을 손상역학에 기반하여 역학적으로 기술하고 자체개발한 유한요소해석코드에 탑재하여 이를 전산적으로 시뮬레이션한다. 정도 높은 용접구조물 전산피로시험법의 개발을 위해 용접잔류응력과 재료파라미터를 자체개발한 유한요소해석코드를 통해 구현한다. 개발된 전산피로시험법은 용접구조물의 피로시험 결과와 비교함으로서 제안 기법의 적합성 및 유용성을 검증한다.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.3
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• pp.51-57
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• 2019

Post curing effects are estimated by specimen tests. Propellant specimen accelerated aging tests are performed when post curing is estimated to be complete and the coefficients of Arrhenius aging equations are acquired. Simulated motors with cylindrical grain are designed and fabricated to confirm the application. Accelerated aging tests are conducted, and aged properties are measured and estimated for the inner bore, center and bond parts of the grain. The measured aging ratios of the modulus are compared with the ones predicted by the equations. As the results, the accelerated aging equations predict well the propellant aging trends; however, some differences are observed at the bond part. Therefore, the specimen extraction part must be carefully chosen to suit the test purpose when a rocket motor grain is used for the aging test.

• Korean Journal of Materials Research
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• v.3 no.4
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• pp.361-371
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• 1993

Among the various test methods for stress corrusiun cracking(SCC) susceptibility evaluatiun, the slow stram rate test(SSHT) method is a rapid and effective nwthod to evaluate the SCC susceptibility of metal in relatively short time. But it is very difficult to analyze the microfracture behaviors in SCC process by using the test(SSRT) method only. Up to now, it has been well known that the acoustic emission(AE) test is the effective technique to monitor the microcrack initiation and propagation in material fracture pmcess. Therefore. in this paper, we analyzed the correlation between the see process and the characteristics of AE signal by using the SSHT and the AE test. According to the test results. the AE signals produced from the material microfracture were clearly depended on the test environment. The AE signal characteristics generated during see process in synthetic sea water were comparatively greater than those. in air. In addition, the SCC behaviors could be definitely evaluated by the amplitude parameter of AE signals.

• Journal of the Korean Society of Propulsion Engineers
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• v.1 no.2
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• pp.1-11
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• 1997

During hydroproof test of composite pressure vessel, acoustic emission signal was measured and analyzed to evaluate structural integrity of composite motor case. When pressure was held for 1 min. at constant pressure from low pressure level to high pressure level, the pattern of hit rate of good composite pressure vessel is increased with higher value than that of bad composite pressure vessel. This report also presents detection possibility of burst location approximately in the range of 25∼36％ of burst pressure using energy rate. In case that it is difficult to detect burst location of composite motor case, it is possible to detect burst location, i.e. structurally weak location of composite pressure vessel with applying same pressure lower than maximum expected operating pressure(MEOP) repeatedly.

• Computational Structural Engineering
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• v.9 no.1
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• pp.125-132
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• 1996

This study is to propose a practical and realistic reliability analysis by ETCM (Expected Total Cost Minimization). One of the main objectives is intended to propose the safety assessment and capacity rating of existing reinforced concrete members by evaluation index, that is RF(Rating Factor) from the results of the field test and inspection for reinforced concrete bridge. ETCM method is used for the reliability analysis of the proposed models. The proposed reliability model and method are applied to the safety assessment and system factors of reinforced concrete members.

• Defense and Technology
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• no.10 s.164
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• pp.38-42
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• 1992

복합재 압력용기의 제작 및 사용중에 발생하는 결함(손상)의 비파괴검사를 통해 구조물의 건전성을 평가하는 것은 제품의 품질보증 관점에서 아주 중요합니다. 복합재에서는 여러 종류의 결함이 동시에 존재할수 있으며, 결함-기계적 성질-비파괴특성 사이의 상호관계는 완전히 알려져 있지 않습니다. 이글에서는 복합재 연소관에 존재하는 결함의 위험도와 결함 탐지를 위한 비파괴 검사 기법에 대해 먼저 살펴보았습니다. Filament Winding으로 제조한 복합재 연소관의 Proof Testing과 관련해 음향방출(AE)법에 의한 최근의 연구결과를 살펴본 다음, 연소관의 신뢰도 확보를 위한 비파괴 평가 방법에 대해 앞으로의 연구 방향을 제시하였습니다

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.239-245
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• 1998

GOMS 평가는 운전원 개인의 인지과정에 초점을 두어 직무 절차의 학습시간과 직무 실행시간을 예측하고 직무 실행시 요구되는 인지부하를 분석한다. 하지만 실제 원전의 운전은 그룹에 의해 이루어지므로 운전원간 의사소통과 직무의 상호 의존관계를 고려하여 기존의 GOMS를 확장한 분산형 GOMS를 고안하였다. 본 논문에서는 분산형 GOMS 평가기법을 CE형 원전의 비상운전절차서에 시험적으로 적용해 본 결과를 제시한다.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2006.03a
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• pp.217-236
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• 2006

In this study, the LCM was applied as the preliminary study for the cutterhead design of TBM and the drilling performance evaluation. The optimum cutting condition is obtained from the LCM tests and the effects of the design factors of IBM cutterhead, such as penetration depth and cutter spacing, on drilling performance are estimated. In this study, hence, to predict the accurate performance of TBM, instead of one-dimensional penetration depth applied in existing studies, three-dimensional cutting volume was quantified and measured. For this, the digital photogrammetry technique was applied to the LCM tests. Also, AUTODYN 2D was applied to investigate the applicability of the numerical analysis technique to simulate the cutting process of rock by the TBM disc cutter.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.11
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• pp.1407-1413
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• 2013

The swing motion drive unit of a hybrid excavator is composed of an electrical motor instead of a hydraulic motor that is used in hydraulic excavators. The method to assess and guarantee the reliability of a hybrid excavator should consider combining the mechanical and the electrical failure mode effects. In particular, the swing reduction gear set of a hybrid excavator is operated under severe outdoor conditions; therefore, an accelerated life test, which is based on field operating condition, should be conducted for the newly developed reduction gear set. In this study, various qualitative methods for reliability engineering, such as FMMA, FMECA, FTA, and QFD, were used to develop the accelerated life test method for the swing drive reduction gear set for the hybrid excavator.