• 한국항행학회논문지
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• 제13권1호
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• pp.19-26
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• 2009

항공관제시스템은 안전하고 신뢰할 수 있는 공항 운영을 위해 절대적으로 높은 신뢰성이 요구된다. 본 연구에서는 서버 워크스테이션과 네트워크를 포함하는 ATM 하드웨어 시스템의 신뢰성을 분석하였다. 구체적으로 하드웨어 신뢰성 평가에 자주 사용되는 신뢰도 불록도(Reliability Block Diagram)와 고장수목분석법(Fault Tree Analysis)을 이용하여 분석하였다. 분석 실험은 Relex 사의 Reliability Studio를 이용하여 ATM 하드웨어 시스템의 신뢰도를 예측하였다.

• 항공우주기술
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• 제2권1호
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• pp.205-212
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• 2003

신뢰성이란 부품이나 시스템이 얼마나 오랫동안 안심하고 사용할 수 있는가를 정량적 수치로 표현하는 미래의 품질 개념으로 앞으로 제품의 국제적인 경쟁력을 갖추기 위하여 필수적으로 요구되는 기술이다. 국내에서도 제품의 신뢰성 향상에 대한 관심과 필요성이 더욱 고조됨에 따라, 정부에서도 세계적 수준의 신뢰성 평가 인프라를 구축하기 위해 “신뢰성 향상 기반 구축사업”을 적극적으로 추진하고 있으며, 대학, 연구기관 및 전자, 자동차, 중공업 등 수출업체에서 신뢰성에 관한 연구 및 시험평가센터를 설립하여 본격적으로 신뢰성 문제를 다루고 있다. 본 논문에서는 신뢰성 향상 사업에 대한 국내의 현황을 소개하고 항공우주분야에 대한 신뢰성 인증제도 도입의 필요성에 대하여 검토하였다.

• Journal of Astronomy and Space Sciences
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• 제20권3호
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• pp.217-226
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• 2003

MSC (Multi-Spectral Camera) is the payload of KOMPSAT-2, which is being developed for earth imaging in optical and near-infrared region. The design of the MSC is completed and its reliability has been assessed from part level to the MSC system level. The reliability was analyzed in worst case and the analysis results showed that the value complies the required value of 0.9. In this paper, a calculation method of reliability for the MSC system is described, and assessment result is presented and discussed.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권4호
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• pp.325-331
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• 2017

Purpose: There is active research that improves both reliability and fatigue life of structures which widely used in the aerospace fields of defense industry. The effects of three parameters (pressure, peening time, nozzle distance) on Almen intensity and coverage will be investigated by using the experimental and analyzed data. Methods: we employed a Box-Behnken design. Additionally, to verify the validity of the optimal condition obtained from experimental results, metallurgical analyses of the shot-peened aerospace part were conducted with respect to surface morphology, residual stress. Results: Optimal shot peening condition is determined as (distance, pressure, time) by optimizing simultaneously the two responses of intensity and coverage. At the optimal peening condition the prediction interval for Almen intensity is well within the required range. And, the validity of the condition was checked by using the real aerospace aluminum alloy plate. Conclusion: Shot peening introduces significant levels of compressive residual stress and induces improves both reliability and fatigue life of structures.

• Advances in aircraft and spacecraft science
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• 제4권4호
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• pp.467-486
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• 2017

A method for decoupling reliability based design optimization problem into a set of deterministic optimization and performing a reliability analysis is described. The inner reliability analysis and the outer optimization are performed separately in a sequential manner. Since the outer optimizer must perform a large number of iterations to find the optimized shape and size of structure, the computational cost is very high. Therefore, during the course of this research, new multilevel reliability optimization methods are developed that divide the design domain into two sub-spaces to be employed in an iterative procedure: one of the shape design variables, and the other of the size design variables. In each iteration, the probability constraints are converted into equivalent deterministic constraints using reliability analysis and then implemented in the deterministic optimization problem. The framework is first tested on a short column with cross-sectional properties as design variables, the applied loads and the yield stress as random variables. In addition, two cases of curvilinearly stiffened panels subjected to uniform shear and compression in-plane loads, and two cases of curvilinearly stiffened panels subjected to shear and compression loads that vary in linear and quadratic manner are presented.

• 시스템엔지니어링학술지
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• 제2권1호
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• pp.31-36
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• 2006

Development of launch vehicle needs a large-scale and complicated System Engineering discipline interfacing to small-quantity production with special manufacturing processes. In general, the System Engineering discipline of launch vehicle has its relationship with Production, Operations, Product Assurance and Management disciplines and its internal partitions into the functions of System Engineering Integration & Control, Requirements Engineering, Analysis, Design and Configuration and Verification. As a function of Product Assurance, reliability of launch vehicle plays an significant role in risk management, system safety, flight safety and launch certification through design assurance. Moreover, major functions of systems engineering are integrated by means of reliability in the phases of design and verification. Therefore, derailed identification of system engineering interfaces of reliability, and execution of tasks for reliability assurance is required for successful development of launch vehicle. This paper identifies specific pattern and mechanism of the interfaces between reliability and system engineering.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2007년 추계학술발표대회 개요집
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• pp.276-278
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• 2007

Many processes have been introduced to join PE pipes, but most of these methods have lots of disadvantages such as costs and lack of reliability, etc. Recently due to the benefits of cost, safety and reliability, the but welding has been paid much attention to join PE pipes. In case of butt welding, the heat plate which is used to melt PE pipes is the most critical equipment. In this study, after designed secondary developed heat plate of new shape, the PE double wall pipes were but-welding by using the developed heat plate and secondary developed heat plate and comparison of weld-zones and tensile test were performed. As results of tensile test, tensile strengths using secondary developed heat plate were measured higher $1.17{\sim}1.5$ than using developed heat plate.

• Journal of information and communication convergence engineering
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• 제15권2호
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• pp.117-122
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• 2017

Three-dimensional integrated circuits (3D ICs), starting with memory cubes, have entered the mainstream recently. The benefits many predicted in the past are indeed delivered, including higher memory bandwidth, smaller form factor, and lower energy. However, 3D ICs have yet to find their deployment in aerospace applications. In this paper we first present key design tools and methodologies for high performance, low power, and reliable 3D ICs that mainly target terrestrial applications. Next, we discuss research needs to extend their capabilities to ensure reliable operations under the harsh space environments. We first present a design methodology that performs fine-grained partitioning of functional modules in 3D ICs for power reduction. Next, we discuss our multi-physics reliability analysis tool that identifies thermal and mechanical reliability trouble spots in the given 3D IC layouts. Our tools will help aerospace electronics designers to improve the reliability of these 3D IC components while not degrading their energy benefits.

• 항공우주시스템공학회지
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• 제10권1호
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• pp.51-58
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• 2016

In this paper, we present some results on No-failure accelerated life test of aerial vehicle for reliability demonstration. The design of general accelerated life test consists of the three phases: 1) Estimating normal life test time of a single product from Weibull distribution model; 2) Determining the acceleration factor (AF) by utilizing the relation between the life of mechanical components and the applied torque; 3) Calculating the accelerated life test time, which comes from dividing the estimated normal life test time into AF. Then, we applied the calculated life test time to the real reliability test of the flap actuating system, while considering the requirement specification for mechanical components and operating environment of the actuation system. Real experimental processes and results are presented to validate the theory.

• 항공우주시스템공학회지
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• 제18권2호
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• pp.21-28
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• 2024

최근 뉴스페이스 시대라고 불릴 만큼 우주 산업 분야는 점점 커져가고 있으며, 초소형 위성의 중요성도 또한 커지는 추세이다. 초소형 위성은 주로 COTS 부품을 사용하며 우주급 부품에 비해 낮은 신뢰도를 가지고 있지만 개발 기간, 비용, 성능 측면에서 장점을 가지고 있어 사용성이 확대되고 있다. COTS(Commercial Off-The-Shelf)는 상용으로 판매되는 제품을 가리키며, 이는 특정 조직이나 프로젝트에서 직접 제작하는 대신 시장에서 구입하여 사용되는 것을 의미한다. 위성은 발사되는 순간부터 수리가 불가능 하기 때문에 신뢰도 예측의 중요성은 크게 작용한다. 근래에는 신뢰도 예측 시 부품에 대한 인자 뿐만 아니라 시스템 level에서의 신뢰도를 예측하는 것이 더 중요하게 적용되고 있다. 따라서 본 연구에서는 신뢰도 예측 규격인 MIL-HDBK-217F와 업데이트된 RiAC-HDBK-217Plus와 FIDES를 비교해 본다. 그리고 FIDES 예측 기준에서 다양한 산업 분야에 적용될 수 있도록 구성한 제조업체의 품질 보증 요소를 세분화하여 우주 산업에 적합한 점수가 반영될 수 있도록 하였다.