• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.5
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• pp.489-496
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• 2010

The power generation and chemical industry have been subjected to further material degradation with long term operations and need to predict the remaining service life of components, such as reformer tube and steam turbine rotor, that have operated at elevated temperatures. As a non-destructive technique, replication method with reliable metallurgical life and microstructural soundness assessment has been recognized with strongly useful method until now. Developments of this method have variously accomplished by new quantitative approach, such as carbide analysis, with A-parameter and grain deformation method. An overview of replication, some new techniques for material degradation and life assessment were introduced in this paper. Also, on-site applications and its reasonableness were described. As a result of having analyzed microstructure by replication method, carbide approach was quantitatively useful to life assessment.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.209-213
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• 2003

It is advantage of accelerated vibration testing to compress service exposures to operating vibration into a reduced laboratory test by increasing the amplitude or frequency of the applied input excitations. This paper proposes an accelerated test method to estimate the high-cycle fatigue life under random excitation. The method consists of conducting a test with amplified input excitation and extrapolating linearly the lift in the accelerated condition into the real lift in field condition. The extrapolation is carried out applying the high-cycle irregular excitation fatigue theory including the rainflow counting, Miner’s damage accumulation rule, and Goodman’s mean stress correction. As a verification, those estimated lift is compared with that acquired by experiment f3r the simple case of spot welding specimen with good agreement. This testing procedure will provide an useful scheme that can reduce testing period associated with developing time schedule of new product.

• Journal of the Korea Safety Management & Science
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• v.17 no.1
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• pp.289-300
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• 2015

According to the generalization of mobile device use in our life, the complexity and diversity of mobile applications are increased, and thus the importance of application test to find faults and errors quickly and easily before release grows. This paper reviews the current automatic testing methodologies for mobile device applications and their element technologies. Also, well-known commercial tools for automatic testing are surveyed and case studies of their recent industry applications in domestic and foreign countries are performed.

• Proceedings of the Korean Reliability Society Conference
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• 2006.05a
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• pp.149-157
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• 2006

에스컬레이터 스텝 및 수평보행기 팰릿의 가속수명시험 국제 기준인 5백만회 시험조건 및 하중조건의 등가 현장 수명에 대한 근거를 산출하였다. 업체 및 산기원의 시험 데이터로부터 Weibull 모델을 추정하여 분석한 결과 에스컬레이터 스텝 및 수평보행기 팰릿의 형상모수가 각각 2.4$\sim$2.6 및 2.7$\sim$2.8로 산출되었다. 이 형상모수를 이용하여 본 연구에서 대상으로 한 에스컬레이터 스텝 및 수평보행기 팰릿의 B$_{10}$ 수명이 각각의 목표 수명 7년과 6년을 보증할 수 있음을 확인하였다.

• Journal of Information Processing Systems
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• v.6 no.1
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• pp.21-32
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• 2010

Software maintenance is one of the major activities of the software development life cycle. Due to the time and cost constraint it is not possible to perform exhaustive regression testing. Thus, there is a need for a technique that selects and prioritizes the effective and important test cases so that the testing effort is reduced. In an analogous study we have proposed a new variable based algorithm that works on variables using the hybrid technique. However, in the real world the programs consist of multiple modules. Hence, in this work we propose a regression testing algorithm that works on interprocedural programs. In order to validate and analyze this technique we have used various programs. The result shows that the performance and accuracy of this technique is very high.

• Molecules and Cells
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• v.19 no.3
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• pp.428-435
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• 2005

This study was carried out to assess the potential of SSR markers for variety identification by comparing SSR markers and morphological traits in tests of distinctiveness, uniformity, and stability (DUS) of pepper (Capsicum annuum L.) varieties. Twenty-seven SSR markers were polymorphic in 66 pepper varieties, revealing a total of 89 alleles. Average polymorphism information content (PIC) value was 0.529, ranging from 0.03 to 0.877. Cluster analysis of the band patterns separated the varieties into three groups corresponding to varietal types. Morphological trait-based clustering showed some degree of similarity to dendrogram topologies based on the SSR index. However, no significance correlation was found between the SSR and morphological data. SSR markers could be used to complement a DUS test of a candidate variety and to select complimentary varieties by pre-screening existing varieties in the context of protecting new varieties of pepper.

• The Korean Journal of Applied Statistics
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• v.8 no.2
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• pp.121-132
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• 1995

In this paper we consider optimal designs of partially step-stress life testing which is deviced for k-component series systems with the considerably long life time. Test items are first run simultaneously at use condition for a specified time, and the surviving items are then run at accelerated condition until a predetermined censoring time. The optimal criterion for the change time to accelerated condition is to minimized either the generalized asymptotic variance of maximum likelihood estimators of the hazard rates at use condition and the acceleration factors or the asymptotic variance of the maximum likelihood estimators of the acceleration factors.

• Journal of the Korean Statistical Society
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• v.26 no.1
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• pp.101-116
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• 1997

This is primarily an expository paper that presents several nonparametric procedures for testing exponentiality against certain monotonicity properties of the mean residual life function, tests against the trend change in such function attract a great deal of attention of late in reliability analysis. In this note, we present some of the known testing procedures regarding the behavior of mean residual life function. These tests are also compared in terms of asymptotic relative efficiency and empirical power against a few alternatives. The tests based on incomplete data are also briefly discussed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.77-79
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• 2009

The paper is to evaluate for reliability of 4W LED Lamp using internal converter by ALTs(Accelerated Life Tests). The recently, some of KS were established by law of LED Modules for Lighting(KS C 7651, 7652, 7653, 7655, 7656, 7657, 7658 and 7659), but reliability assessment methods of LED Lamps had not been established. Therefore, the paper aided companies to perform accelerated life testing(temperature 60 $^{\circ}C$, humidity 90 %) for themselves.

• International Journal of Reliability and Applications
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• v.6 no.1
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• pp.1-12
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• 2005

A new test for testing that a life distribution is exponential against the alternative that it is harmonic new better (worse) than used in expectation upper tail HNBUET (HNWUET), but not exponential is presented based on the highly popular 'Kernel methods' of curve fitting. This new procedure is competitive with old one in the sense of Pitman's asymptotic relative efficiency, easy to compute and does not depend on the choice of either the band width or kernel. It also enjoys good power.