• Journal of Advanced Navigation Technology
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• v.13 no.1
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• pp.19-26
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• 2009

Air Traffic Management (ATM) system requires extremely high reliability for the safe and dependable operations in the airport. This paper reports a study on the reliability of the prototype ATM hardware system including the servers and local area networks. Reliability Block Diagram and Fault Tree Analysis on the prototype ATM hardware were performed.

• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.205-212
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• 2003

Reliability means that certain parts or systems maintain its best qualities and functionalities within certain periods and is the prospective quality which the safe life of products is indicated by quantitative values and the highest level of reliability of the products is required to attain in the highly competitive business world. In Korea, there have been a significant growth in the field of reliability and government promotes the "Reliability Improvement Project" to establish infrastructure to conduct reliability assessment and certification. The importance and necessity is well recognized among researchers and engineers working in the research institutions and the manufacturing industries and many industries invest a great amount of money and effort in improving the reliability of its products. In this paper, the promotional status of reliability improvement project and necessity of establishment of the reliability certification system for aerospace field is presented.

• Journal of Astronomy and Space Sciences
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• v.20 no.3
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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.

• Journal of Applied Reliability
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• v.17 no.4
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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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• v.4 no.4
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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.

• Journal of the Korean Society of Systems Engineering
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• v.2 no.1
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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.

• Proceedings of the KWS Conference
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• 2007.11a
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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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• v.15 no.2
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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.

• Journal of Aerospace System Engineering
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• v.10 no.1
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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.

• Journal of Aerospace System Engineering
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• v.18 no.2
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• pp.21-28
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• 2024

In light of the rapid development of the space industry, there has been increased attention on small satellites. These satellites rely on components that are considered to have lower reliability compared to larger-scale satellites. As a result, predicting reliability becomes even more crucial in this context. Therefore, this study aims to compare three reliability prediction techniques: MIL-HDBK-217F, RiAC-HDBK-217Plus, and FIDES. The goal is to determine a suitable reliability standard specifically for nano-satellites. Furthermore, we have refined the quality assurance factors of the manufacturing company. These factors have been adjusted to be applicable across various industrial sectors, with a particular focus on the selected FIDES prediction standard. This approach ensures that the scoring system accurately reflects the suitability for the aerospace industry. Finally, by implementing this refined system, we confirm the impact of the manufacturer's quality assurance level on the total failure rate.