• Computational Structural Engineering
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• v.5 no.1
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• pp.97-108
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• 1992

This paper is an attempt to account for the uncertainty of the residual strength in the reliability analysis of structural systems. For this purpose the stochastic finite element method(SFEM) is linked to the system reliability analysis procedure. The stochastic finite element is known to be able to a more explicitly consider the effect of uncerainties of material and geometric variables on those of load effects in structural analysis procedure. The method has been applied to system as well as component reliability analysis of a plane structure. Comparison of the results by the present approach is made with the method in which the residual strength of failed component is treated as deterministic variable. Several case studies have been carried to show the effect of uncertainty in residual strength of a member after failure. Is has been conformed that reidual strength very much affect the system reliability level. It can be, hence, concluded that the uncertainties in the post-ultirnate behaviour may have to be taken into account in the system reliability analysis for a better a ssessment of the system reliability especially for a structure of which member behaviour is modelled as asemi-brittle model. And then the stochastic finite element method can efficiently evaluate the system reliability.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.1
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• pp.25-36
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• 1995

The application of the reliability analysis is investigated as a probabilistic approach to the assessment of ship's structural strength and to the establishment of design format for longitudinal strength. Reliability analyses are carried out for 34 ships of tankers and bulk carriers built in HHI for some failure modes such as tensile yielding, compressive buckling and ultimate strength of hull girder. The safety assessment of each ship, the calculation of sensitivity factors and the derivation of target reliability index are performed. As results. the difference of reliability indices among ships is great for all modes. To provide more uniform levels of safety the establishment of new strength criteria using partial safety factors is performed. The partial safety factors for the design format are obtained according to the AFOSM method and the reliability-conditioned(RC) method. Finally, a design format using partial safety factors has been proposed. We could find out that new strength criteria can produce consistent reliability indices which are close to the target value.

• Industry Promotion Research
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• v.7 no.4
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• pp.1-8
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• 2022

There are many one-shot devices that are used once and thrown away. One-shot devices such as firecrackers and ammunition are typical, and they are stored for a while after manufacture and then disposed of after use when necessary. However, unlike general operating systems, these one-shot devices have not been properly evaluated. This study first examines what the government does to secure reliability in the case of ammunition through ammunition stockpile reliability program. Next, in terms of statistical analysis, we show what the reliability analysis methods are for one-shot devices such as ammunition. Specifically, we show that it is possible to know the level of reliability if sampling inspection plan such as KS Q 0001 which is acceptance sampling plan by attributes is used. Next, non-parametric and parametric methods are introduced as ways to determine the storage reliability of ammunition. Among non-parametric methods, Kaplan-Meier method can be used since it can also handle censored data. Among parametric methods, Weibull distribution can be used to determine the storage reliability of ammunition.

• Journal of the Korea Society for Simulation
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• v.15 no.4
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• pp.129-136
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• 2006

Grid computing has been appeared for solving large-scaled data which are not solved by a single computer. Grid computing is a new generation platform which connects geographically distributed heterogeneous resources. However, gathering heterogeneous distributed resources produces many difficult problems. Especially. to assure resource reliability is one of the most critical problems. So, we propose a grid resource scheduling model using grid resource reliability measurement. We evaluate resource reliability based on resource status data and apply it to the grid scheduling model in DEVSJAVA modeling and simulation. This paper evaluates parameters such as resource utilization, job loss and average turn-around time and estimates experiment results of our model in comparison with those of existing scheduling models such as a random scheduling model and a round-robin scheduling model. These experiment results showed that the resource reliability measurement scheduling model provides efficient resource allocation and stable Job processing in comparison with a random scheduling model and a round-robin scheduling model.

• Proceedings of the Korean Reliability Society Conference
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• 2000.04a
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• pp.109-114
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• 2000

제품의 사용환경에서의 고장데이터는 일반적으로 보증기간 동안 발생하는 클레임을 처리하거나 A/S를 하는 과정에서 얻어지게 되는데 이러한 현장데이터를 적절한 방법으로 분석하여 제품의 신뢰도에 대한 올바른 정보를 얻고 품질개선에 활용하는 것은 기업에 있어서 매우 중요하다. 본 연구에서는 사용현장 데이터의 수집방법 연구와 현장 데이터의 신뢰성 분석 방법의 연구 흐름을 살펴보고 이후 사용현장데이터의 신뢰성 분석 방법연구에 도움을 주는 것이 목적이다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.475-481
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• 1993

The objective of this study is to develope the reliability prediction model for Float Rated Integrating Gyroscope( :FRIG) at maximum loading. The equation of motion for FRIG is firstly derived to set up the reliability prediction model. To analysis reliability or all parts of the gyro is not easy due to their complicated structure. Therefore the failure parts are chosen by Failure Mode Effective Analysis (:FMEA). F.E.M is utilized to calculate loads for the selseced rotating assembly and pivot / jewel. The technical reliability is calculated by applying reliability design theory with these results and the performance reliability is sought through distribution estimation with error test data. The bulk reliability of gyroscope is sought by applying the two results. The present prediction results are compared with the accumulation time in good agreement.

• Journal of Applied Reliability
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• v.6 no.1
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• pp.63-91
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• 2006

According to the rapid development of science technologies, a life and development cycle of products are getting shorter and structures and functions become more complex so that the reliability requirement of customers is getting greater for components in the products. However, most domestic mechanical components are manufactured by small and medium-sized companies, who are manufacturing in poor economic and technical condition. Because of this, assessment technologies and equipment to predict and guarantee the reliability are very weak. For this reason, it is the fact that many customers neglect the domestic mechanical components which fail to win the reliability. Korean government has been trying to eliminate the problem by establishing 18 reliability assessment centers in 2000 and performing R-Mark certification promotion and constructions of the foundation for reliability assessment to rebuild the reliability on the domestic components and materials. Korea Institute of Machinery and Materials has been designated as a supervising organization for reliability assessment in the machinery filed for 5 years. In this paper, we would like to introduce effective and systematized 12 steps of reliability substantiation test on mechanical components with know-how we achieved during the period.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.578-580
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• 2009

Wireless Sensor Networks(WSNs) has been used for various applications. It is optimized to low power operation than various function and transmission reliability because of limited power by batteries. but it is necessary to guarantee of reliability for using exact data for more diversity purpose. In WSNs environment composed by multi-hop, it is guarantee to end-to-end transmission reliability based hop-by-hop reliability. however, IEEE 802.15.4 standard is not consider link-layer reliability. in this paper, we propose energy efficient Reliable Link-layer Protocol for Wireless Sensor Networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4B
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• pp.332-345
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• 2011

As weapon systems are evolving into more advanced and complex ones, the role of the software is becoming heavily significant in their developments. Particularly in the war field of today as represented by the network centric warfare(NCW), the reliability of weapon systems is definitely crucial. In this context, it is inevitable to develop software reliably enough to make the weapon systems operate robustly in the combat field. The reliability engineering activities performed to develop software in the domestic area seem to be limited to the software reliability estimations for some projects. To ensure that the target reliability of software be maintained through the system's development period, a more systematic approach to performing software reliability engineering activities are necessary from the beginning of the development period. In this paper, we consider the software reliability in terms of the development of a weapon system as a whole. Thus, from the systems engineering point of view, we analyze the models and methods that are related to software reliability and a variety of associated activities. As a result, a process is developed, which can be called the software reliability engineering process for weapon systems (SREP-WS), The developed SREP-WS can be used in the development of a weapon system to meet a target reliability throughout its life-cycle. Based on the SREP-WS, the software reliability could also be managed quantitatively.

• Journal of Applied Reliability
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• v.5 no.1
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• pp.181-192
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• 2005

In this paper, we consider a process for design for reliability(DFR) in design and development phases. The procedure of GE for DFR is applied to develope and analyze a washing machine with required reliability and the detailed procedure is proposed.