• Journal of Korean Society for Quality Management
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• v.27 no.4
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• pp.241-255
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• 1999

This paper concerns Reliability Analysis System(RAS) developed by LG Electronics, Inc. for collecting, classifying, and analyzing field failure data. To develop this system, a database for the management of field failure data was built and several functions were included to analyze and assess the product reliability. Nonparametric estimation and cumulative hazard plotting techniques were applied to estimate the reliability for a specific period. This system serves not only engineers in charge of quality but also designers who wish to monitor the reliability of their own products.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.10a
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• pp.34-39
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• 1989

Recent trends in design standards development have encouraged the use of probabilistic limit sate design concepts. Reliability analysis adopted in those advanced countries have the potentials that they afford for symplifying the design Process arid placing it on a consistent reliability based for various construction materials. This study is proposed in the reliability analysis of plane frame structures using second-order moment method(Level-II they). Lind-Hasofer's minimum distance method is use in the derivation of an mathematical algorithm as well as an determination of Correlation cofficients, reliability index and total reliability index depending on the multiple failure modes. In addition. This study is employed as a practical tool for the approximate reliability analysis. Results of the numerincal analysis showed that the difference between the reliability index of the failure probability of the multiple failure modes and the total reliability index of the failure probability with the simultaneous failure modes deviated nearly 3∼10% depending on tile performance functions.

• Steel and Composite Structures
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• v.24 no.3
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• pp.369-382
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• 2017

This study investigates the reliability of the performance levels of moment resisting steel frames subjected to lateral loads such as wind and earthquake. The reliability assessment has been performed with respect to three performance levels: serviceability, damageability, and ultimate limit states. A four-story moment resisting frame is used as a typical example. In the reliability assessment the uncertainties in the loadings and in the capacity of the frame have been considered. The wind and earthquake loads are assumed to have lognormal distribution, and the frame resistance is assumed to have a normal distribution. In order to obtain an appropriate limit state function a linear relation between the loading and the deflection is formed. For the reliability analysis an algorithm has been developed for determination of limit state functions and iterations of the first order reliability method (FORM) procedure. By the method presented herein the multivariable analysis of a complicated reliability problem is reduced to an S-R problem. The procedure for iterations has been tested by a known problem for the purpose of avoiding convergence problems. The reliability indices for many cases have been obtained and also the effects of the coefficient of variation of load and resistance have been investigated.

• International Journal of Reliability and Applications
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• v.9 no.1
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• pp.95-112
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• 2008

This paper gives the reliability equivalence factors of a parallel system with n independent and non-identical components. It is assumed here that, the failure rates of the system's components are constants. We used three different methods to improve the system given. Two reliability characteristics (the mean time to failure and the reliability function) are used to perform the system improvement. For this purpose, the reliability functions and the mean times to failures of the original and improved systems are obtained. The results given in this paper generalize the results given in the literatures by setting n = 1, 2. An illustrative numerical example is presented to compare the different reliability factors obtained.

• Journal of the Korea Safety Management & Science
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• v.8 no.2
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• pp.91-102
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• 2006

Korea Railroad Research Institute developed the driverless rubber-tired Korean-AGT system from 1999 to 2005 and has done its performance and reliability tests on the test line at Gyeongsan-city. We made the reliability management program to control required the RAMS(reliability, availability, maintainability & safety) of the K-AGT system. Therefore, we demonstrated the development and application of Reliability DB program. The main functions of K-AGT Reliability DB program manages failures and maintenance data systematically from the test line through test period and provides various analysis results based on the inputted data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.7
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• pp.1354-1359
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• 2011

This paper presents a novel methodology for improving the reliability of electromagnetic devices and machines based on the reliability-based design optimization method. To achieve this, the method includes reliability analysis and optimization process taking into account uncertainties of design variables. One of the first-order reliability analysis techniques, called reliability index approach, is adopted to evaluate the reliability of performance functions with respect to probabilistic design variables. The proposed method has been successfully applied to designing a superconducting magnetic energy storage system. For verifying the efficiency and accuracy of the method, the results are compared with those of conventional optimization methods.

• Journal of the Korean Society of Industry Convergence
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• v.12 no.4
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• pp.209-214
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• 2009

Usually, it says that reliability is failure rate achieved by required functions for some period under limited use environment conditions. The reliability can be researched by automotive part or system module and it can be affected by using environment condition, such as using atmosphere temperature and using user's behavior. Also, the time can be influence on the reliability. Recently, the oil leakage from eng oil pan was raised by customer in the field. So, there is the purpose of this paper that research predicting the reliability of eng oil pan efficiently by using reliability method described below.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.8 s.251
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• pp.985-992
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• 2006

Many methods for reliability analysis have been studied and one of them, a moment method, has the advantage that it doesn't require sensitivities of performance functions. The moment method for reliability analysis requires the first four moments of a performance function and then Pearson system is used for the probability of failure where the accuracy of the probability of failure greatly depends on that of the first four moments. But it is generally impossible to assess them analytically for multidimensional functions, and numerical integration is mainly used to estimate the moment. However, numerical integration requires many function evaluations and in case of involving finite element analyses, the calculation of the first fo 따 moments is very time-consuming. To solve the problem, this research proposes a new method of approximating the first four moments based on kriging metamodel. The proposed method substitutes the kriging metamodel for the performance function and can also evaluate the accuracy of the calculated moments adjusting the approximation range. Numerical examples show the proposed method can approximate the moments accurately with the less function evaluations and evaluate the accuracy of the calculated moments.

• Journal of Sensor Science and Technology
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• v.27 no.1
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• pp.59-63
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• 2018

Among Internet of things (IoT) applications, the most demanding requirements for the widespread realization of many IoT visions are security and low power. In terms of security, IoT applications include tasks that are rarely addressed before such as secure computation, trusted sensing, and communication, privacy, and so on. These tasks ask for new and better techniques for the protection of data, software, and hardware. An integral part of hardware cryptographic primitives are secret keys and unique IDs. Physical Unclonable Functions(PUF) are a unique class of circuits that leverage the inherent variations in manufacturing process to create unique, unclonable IDs and secret keys. In this paper, we propose a low power Arbiter PUF circuit with low error rate and high reliability compared with conventional arbiter PUFs. The proposed PUF utilizes a power gating structure to save the power consumption in sleep mode, and uses a razor flip-flop to increase reliability. PUF has been designed and implemented using a FPGA and a ASIC chip (a 0.35 um technology). Experimental results show that our proposed PUF solves the metastability problem and reduce the power consumption of PUF compared to the conventional Arbiter PUF. It is expected that the proposed PUF can be used in systems required low power consumption and high reliability such as low power encryption processors and low power biomedical systems.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.10
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• pp.1458-1466
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• 2004

Deterministic optimum designs that are obtained without consideration of uncertainties could lead to unrealiable designs. Such deterministic engineering optimization tends to promote the structural system with less reliability redundancy than obtained with conventional design procedures using the factor of safety. Consequently, deterministic optimized structures will usually have higher failure probabilities than unoptimized structures. This paper proposes the reliability based design optimization technique fur apressure tank considering temperature effect. This paper presents an efficient and stable reliability based design optimization method by using the advanced first order second moment method, which evaluates a probabilistic constraint for more accuracy. In addition, the response surface method is utilized to approximate the performance functions describing the system characteristics in the reliability based design optimization procedure.