• Proceedings of the Korean Reliability Society Conference
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• 2000.04a
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• pp.177-183
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• 2000

As monitoring, testing, and measuring techniques develop, predictive control of components and complete systems have become more practical and affordable. In this paper we develop a statistics-based approach assuming nonlinear degradation paths and time-dependent standard deviation. This approach can be extended to provide reliability estimates and limit value determination in the censoring case fur predictive maintenance policy.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.8
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• pp.9-16
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• 2008

• Proceedings of the Safety Management and Science Conference
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• 2004.05a
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• pp.129-136
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• 2004

Environmental factors for automotive consist of temperature, humidity, vibration(sine & random), gas, an electrical load and so on. These environmental factors are impressed in a automotive. Dependability is essential requirement in many electronic parts. Among components of automotive, the connector connecting electrical signals is one of the most important parts. Automotive -connector is inspected according to each manufacturer's test standard in which dependability should be considered. This paper aims to verify that current test standard is suitable for dependability, and present an inductive life test for automotive connector based on the field data in use-condition.

• International Journal of Contents
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• v.6 no.3
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• pp.25-29
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• 2010

Scanners play an important role in digitally reproducing the color and imaging of original documents used in public offices; however, the current system lacks a standard for digitized documents created by scanners, complicating efforts to create a digitized system. In particular, macrography cannot guarantee the accuracy and reliability of digitalized color documents, pictures, and photographs created by scanners. To this end, we develop a standardized evaluation tool and test target to certify digitalized documents created by a scanner in the domestic environment. In this study, we enhance the accuracy and reliability of scanned data to create an advanced standard evaluation tool for scanners. Moreover, to produce a scanner certification standard, we overcome existing problems related to the growing market. We anticipate that this new standard will see a high degree of application in the current environment.

• Physical Therapy Korea
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• v.20 no.2
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• pp.60-68
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• 2013

The purpose of this study was to assess the intra-rater test-retest reliability of tibial external rotation angle measurement using a smartphone-based photographic goniometer, DrGoniometer (DrG) compared to a three-dimensional motion analysis system (Vicon). The current study showed an interchangeable method using DrG to measure the tibial external rotation angle in standing knee flexion at $90^{\circ}$. Twelve healthy subjects participated in this study. A rest session was conducted 30 minutes later for within-day reliability and five days later for between-day intra-rater test-retest reliability. To assess the validity of the measurement using DrG, we used a three dimensional motion analysis system as a gold standard to measure the angle of tibial external rotation. Intra-class correlation coefficient (ICC) and the standard error of measurement (SEM) values were used to determine the within- and between- day intra-rater test-retest reliability of using DrG and a three dimensional motion analysis system. To assess validity, Pearson correlation coefficients were used for two measurement techniques. The measurement for tibial external rotation had high intra-rater test-retest reliability of within-day (ICC=.88) and between-day (ICC=.83) reliability using DrG and of within-day (ICC=.93) and between-day (ICC=.77) reliability using a three-dimentional motion analysis system. Tibial external rotation angle measurement using DrG was highly correlated with those of the three-dimensional motion analysis system (r=.86). These results represented that the tibial external rotation angle measurement using DrG showed acceptable reliability and validity compared with the use of three-dimensional motion analysis system.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.2 s.43
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• pp.23-33
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• 2007

The growing environmental regulation governs the use of lead by RoHS, WEEE, and then. The electronic industry is moving to replace Pb-bearing solder with Pb-free solder. To use the Pb-free solder, microelectronic industry needs consequently the new reliability appraisal such as the packaging for high temperature process, various mechanical change caused by new solder, and the development of Pb-free sloder for long life of product. The evaluation of solder bar and mechanical properties of joint were performed compared with international standard, and new appraisal standard was established. The solderability and spread ability of Sn-0.7Cu solder material showed up to the standard. Shear test of solder joint using by the solder resulted that the shear strengths after thermal shock or after aging were not much lower than the shear strength of as-soldered and that they were also up to the standard.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.4
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• pp.100-108
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• 2013

In aerospace industry, MTBF (Mean Time Between Failure) and MFTBF (Mean Flight Time Between Failure) are generally used for reliability analysis. So far, especially to Korean military aircraft, MFTBF of avionic equipments is predicted by MIL-HDBK-217 and MIL-HDBK-338, however, the predicted MFTBF by military standard has a wide discrepancy to that of real-world operation, which leads to overstock and increase operation cost. This study analyzes operational data of avionic equipments. Operational MFTBF, which is calculated from operational data, is compared with predicted MFTBF calculated conventionally by military standard. In addition, failure rate trend is investigated to verify reliability growth in operational data, the investigation shows that failure rate curve from operational data has somewhat pattern with decreased failure rate and constant failure rate.

• Journal of the Korean Society of Safety
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• v.26 no.6
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• pp.85-89
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• 2011

Component reliability data were analyzed by using PRinS(Plant Reliability data information System) based on the latest operating experiences of eight KSNPs(Korea Standard Nuclear Power plants), and these new data were applied to the KSNP PSA models. In addition, the existing PSA models were revised for reflecting as-built and as-operated plant conditions. As a result of newly performing PSA in this paper, CDF and LERF were estimated 26.1% and 18.2% lower than the existing values, respectively. It was identified that the risk measures decreased not because of revising the models but because of applying the new component reliability data. The result and the method of this paper could be used when generating plant specific data and performing the living PSA in the future.

• Journal of Korean Society for Quality Management
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• v.44 no.1
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• pp.109-120
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• 2016

Purpose: This study developed a method of determining priorities for evaluating and revising defense standards. Methods: The proposed data integration and refinement methods are used to obtain component reliability information and to determine the frequency of component citation based on Pareto analysis. Based on the reliability information and the frequency of cited components, the target components for quality improvement can be determined and improved using various methods, such as engineering changes, special meetings, additional training, and revising the maintenance manual. Results: Based on the proposed process, we identified components that need to be improved in order to enhance the quality and reliability. Conclusion: Our process will improve the quality and reliability of weapon systems. The proposed process can be adopted for various weapon systems to enhance their quality and reliability, and to reduce military spending.

• Journal of Internet Computing and Services
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• v.7 no.4
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• pp.1-10
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• 2006

We are studying international standard about the software quality evaluation. The software quality has been more important on users and developers. In this paper, first, we study international tendency of the inside and outside of the country in software quality evaluation for evaluating the software quality objectively and quantitatively, Second, we notify a new direction for software quality standard of inside and outside of country. Third, we study on the testing method of software reliability for making use of the software reliability growth model. Fourth, we spread method about standard of the software quality evaluation, fifth, we research into the international standard ISO/IEC 9126 and ISO/IEC 25000 series for evaluation of software quality testing, and we propose to the application plan of software quality testing.