• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.213-220
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• 1999

The life data analysis of the system and component are useful to describe the result of reliability test in product life to satisfy customer's growing need and to change test specifications or design criteria by life data analysis. And vehicle durability tesr occurred market environment. In this study, a statistical analysis for the wear life of brake pad linings helped perform correlation procedure between vehicle durability test and market. B-life values of the brake pad wear life data from both vehicle durability test and marker usage were compared to determine acceleration of the test by the Weibull, normal and log-normal distribution. The acceleration coefficient of the vehicle durability test can access to evaluate design criteria of product and test specification.

• Journal of Applied Reliability
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• v.13 no.1
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• pp.1-10
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• 2013

A Bayesian zero-failure reliability demonstration test method for products with exponential lifetime distribution is presented. Beta prior distribution for reliability of a product is used to design the Bayesian test plan and selecting a prior distribution using a prior test information is discussed. A test procedure with zero-failure acceptance criterion is developed that guarantees specified reliability of a product with given confidence level. An example is provided to illustrate the use of the developed Bayesian reliability demonstration test method.

• Communications for Statistical Applications and Methods
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• v.23 no.6
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• pp.563-574
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• 2016

In this study, we propose several simultaneous tests to detect the difference between means and variances for the two-sample problem when the underlying distribution is normal. For this, we apply the likelihood ratio principle and propose a likelihood ratio test. We then consider a union-intersection test after identifying the likelihood statistic, a product of two individual likelihood statistics, to test the individual sub-null hypotheses. By noting that the union-intersection test can be considered a simultaneous test with combination function, also we propose simultaneous tests with combination functions to combine individual tests for each sub-null hypothesis. We apply the permutation principle to obtain the null distributions. We then provide an example to illustrate our proposed procedure and compare the efficiency among the proposed tests through a simulation study. We discuss some interesting features related to the simultaneous test as concluding remarks. Finally we show the expression of the likelihood ratio statistic with a product of two individual likelihood ratio statistics.

• Journal of Korean Society for Quality Management
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• v.40 no.4
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• pp.599-614
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• 2012

Purpose: We measure service quality based on service process, and examine relationships among product quality, product and service loyalty. Methods: We develop a construct to evaluate process based service quality. We collect data from customers of auto maintenance centers to measure perceived product quality, service and product quality. We test relationships between constructs using structural equation model and regression analysis. Results: Relationships among perceived-product quality, service quality, service loyalty, and product loyalty are all significant. Conclusion: Perceived-product quality has a indirect impact through service quality and loyalty in addition to a direct impact on product loyalty.

• Journal of Power System Engineering
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• v.16 no.3
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• pp.44-50
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• 2012

The reliability qualification test is essential in order to ensure the life time of the product under the normal operation conditions when a new product is developed. The reliability qualification test period has an important impact on the development time of new product. Therefore, some researches to reduce the test time of reliability qualification test have been actively studied. Generally, accelerated life test is well known as one method that can save the test time of the reliability qualification test. This test is conducted under the higher stress condition than normal condition. So we need to investigate what factor affects to the higher stress condition. This paper shows the relationship between the acceleration factor and reliability qualification test period. Especially, we focused on the method to obtain effective acceleration factors under the high temperature condition. Through some experiments for a refrigerator's compressor, we were able to confirm how to increase acceleration factors and how to reduce the reliability qualification test period with minimum samples.

• Journal of KIISE
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• v.42 no.1
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• pp.76-85
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• 2015

Software Product Line Engineering is a collection of techniques that analyze the commonalities and variabilities of the products within a product family and produce products using such information. In Software Product Line Engineering, construction of the correct core assets is very important. To accomplish this, the commonalities and variabilities must first be definitively identified, both to provide traceability between the core assets, and to guarantee the reliability of the products. This paper suggests software product line development and test processes based on CVL for the differentiation of commonalities and variabilities. The proposed approach enables correct building of the core assets through procedures to keep traceability and guarantee the reliability of the products.

• Publications of The Korean Astronomical Society
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• v.24 no.1
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• pp.65-81
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• 2009

We present the performance test results of VLBI Correlation Subsystem (VCS) trial product which was being developed for 1 year from August 2007. It is a core component of Korea-Japan Joint VLBI Correlator (KJJVC). The aim for developing VCS trial product is to improve the performance of VCS main product to reduce the efforts and cost, and to solve the design problems by performing the preliminary test of the manufactured trial product. The function of VCS trial product is that it is able to process the 2 stations-1 baseline, 8 Gbps/station speed, 1.2 Gbps output speed with FX-type. VCS trial product consists of Read Data Control Board (RDC), Fourier Transform Board (FTB), and Correlation and Accumulation Board (CAB). Almost main functions are integrated in the FTB and CAB board. In order to confirm the performance of VCS trial product functions, the spectral analysis, delay compensation and correlation processing experiments were carried out by using simulation and real observation data. We found that the overflow problem of re-quantization after FFT processing was occurred in the delay compensation experiment. We confirmed that this problem was caused by valid bit-expression of the re-quantized data. To solve this problem, the novel method will be applied to VCS main product. The effectiveness of VCS trial product has been verified through the preliminary experimental results, but the overflow problem was occurred.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.8
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• pp.1128-1140
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• 2002

As consumers' alternatives in fashion store selection increase, they select different store types to purchase different product types. Therefore, the probability of patronage mix behavior according to product type increases. Understanding consumers patronage mix behavior, finding out the determinant attributes of fashion stores for each product type are important to retailers and marketers for building a successful merchandising and marketing strategies. Most of the previous researches in store selection and patronage assume consumer behavior as single store patronage, and thus relatively little is known about patronage mix behavior. Also, little attention has been given to product characteristics as an important variable in store patronage behavior. The purposes of this study were to determine the effects of product characteristics in consumers patronage mix behavior. In this study, a theoretical model including product characteristics as an intervening variable between store attributes and patronage behavior was developed. A Questionnaire was developed and data were collected form 464 adult women living in Seoul area in Korea. Factor analysis, paired t-test, ANOVA, Duncan test and discriminant analysis were employed to analyze the data. As a result, the suggested model was partially verified. First, the product characteristic was found to have an effect on perceived importance of store attributes and on determinant attributes of stores. Consumers were found to use different evaluative criteria for store attributes when they purchase different product types. Second, the perceived importance of store attributes was determined by consumer characteristics as well as product characteristics. Third, the determinant attributes in store selection were affected not only by the perceived importance of store attributes but also by the type of product to be purchased.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2418-2423
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• 2005

Hard Disk Drive (HDD) test system is the equipment for the final test of HDD product by iterative read/write/seek test. This paper proposes an expert system for the fault diagnosis of HDD test systems. The purposed expert system is composed with two cascade inference, fuzzy logic and conventional binary logic. The fuzzy logic determines the possibility of the system fault using the test history data, then, the binary logic inferences the fault location of the test system. The proposed expert system is tested in SAMSUNG HDD product line, KUMI, KOREA, and shows satisfactory results.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2424-2429
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• 2005

Hard Disk Drive (HDD) test system is the equipment for the final test of HDD product by iterative read/write/seek test. This paper proposes an expert system for the fault diagnosis of HDD test systems. The purposed expert system is composed with two cascade inference, fuzzy logic and conventional binary logic. The fuzzy logic determines the possibility of the system fault using the test history data, then, the binary logic inferences the fault location of the test system. The proposed expert system is tested in SAMSUNG HDD product line, KUMI, KOREA, and shows satisfactory results.