• Journal of Applied Reliability
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• v.16 no.3
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• pp.216-223
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• 2016

Purpose: This paper suggests the procedure to enhance the reliability of the software of the medical device that is to cure, treat, diagnose, and prevent a disease or an abnormal health conditions. Methods: After test requirements are classified by the software requirements specification for safety and backgrounds, reliability assessment methods are suggested. Results: Verification and validation for function and safety can be performed whether the medical device software are implemented as intended. Conclusion: Procedure on the static analysis, unit test, integration test, and system test are provided for the medical device software.

• Journal of Applied Reliability
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• v.13 no.1
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• pp.55-63
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• 2013

For a reliability assessment of large machinery parts, reliable data should be obtained from testing many samples for a long time. However, in case of testing these samples, testing cost is excessive; in case of life test for long time, power consumption is high; and in case of accelerated test by over load, very high cost is required to build the life testing device. Especially it is very frequent that the expensive device's life has ended during a accelerated test by over load. In this study, the design mechanism of the life testing device which excels in energy saving during the reliability test of large machinery parts has been introduced.

• Journal of Applied Reliability
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• v.2 no.1
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• pp.15-22
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• 2002

This paper is concerned about an Accelerated Life Test for Micro Display Device which is being used in a Projection TV, in order to find a failure mode occurred in field in a short time, to identify a major factor to affect a life, and to estimate a mean life. For this purpose, we selected a temperature as a accelerated factor to perform a test and measured degradation of display device using visual inspection and chromaticity table. In the result of Accelerated Life Test, it is confirmed that failure mode is equal to the degradation of display device by vendor and the Temperature is a major factor to affect a failure. Besides, according as the display device is turned to green as degraded, it is identified that the change of the chromaticity value is one method to measure the degree of the degradation . So, we applied the optimal condition, which consider a cost and life to lower the Temperature which is a major factor acquired by the result of ALT, to PTV design

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.723-730
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• 2006

In the electrical railway, the tension ascension of contact wire is essential to speed up of train and current collection performance of catenary largely depends on the tension. The tension variation rate of the tensioning device used in existing line limits within 5%, and the tension variation rate of the spring-type tensioning device installed at the section where tensioning length is short bounds within 15%. So it is urgent for us to localize it for high speed line, which the tension variation rate is limited within 3%. Therefore in this study, a pulley-type tensioning device for high speed line is developed. To verify the performance of developed device, a performance test, overload test and failure test is carried out under the code of the Kyung-Bu High Speed line. And it is secured durability performance through a fatigue test.

• Journal of Welding and Joining
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• v.31 no.3
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• pp.84-88
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• 2013

These days embedded technology may be the most significant development in the electronics industry. The study focused on the development of active device embedding using flexible printed circuit in view of process and materials. The authors fabricated 30um thickness Si chip without any crack, chipping defects with a dicing before grinding process. In order to embed chips into flexible PCB, the chip pads on a chip are connected to bonding pad on flexible PCB using an ACF film. After packaging, all sample were tested by the O/S test and carried out the reliability test. All samples passed environmental reliability test. In the future, this technology will be applied to the wearable electronics and flexible display in the variety of electronics product.

• Journal of Acupuncture Research
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• v.30 no.3
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• pp.135-140
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• 2013

Objectives : The purpose of this study is to investigate the repeatability and reproducibility of the Ryodoraku acupuncture device. For such device to be accepted as a good apparatus for clinical diagnosis, the score it provides should be stable no matter who measure it or when it is measured, assuming all other conditions equal. Materials and Methods : Three oriental medical doctors who were well trained and fully aware of the usage of the Ryodoraku acupuncture device examined ten randomly selected patients three times. Each doctor measured the Ryodoraku scores three times from each of the 10 selected patients. Three doctors were involved in this experiment to investigate the reproducibility and each of them measured the Ryodoraku scores three times from each patient to investigate the repeatability. Data was analyzed with Friedman test, Spearman correlation test, and intra-class correlation coefficient(ICC) in SPSS ver. 18. Results : 1. The Friedman test showed that there is no statistically significant difference between the 1st, 2nd and 3rd Ryodoraku scores measured by the same examiner. It indicates that the Ryodoraku acupuncture device provides the repeatability. 2. Spearman correlation test confirmed the results obtained by the Fiedman test by showing that there exists a strong positive correlation between the three Ryodoraku scores measured by the same examiner. 3. A very high ICC among the three examiner assured that the Ryodoraku acupuncture device achieves the reproducibility. Conclusions : The Ryodoraku acupuncture device achieves the repeatability and reproducibility. However, we still recommend that a doctor trained to a certain level use the Device to carry out the diagnosis. Also, to improve the device in terms of Reproducibility even more, it should be considered to provide a manual for the exact usage.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.6
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• pp.42-49
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• 2014

Test device using virtual engine simulator can help reduce the number of engine tests through tests similar to the actual engine tests and repeat the test under the same condition, and thus reduce the engine maintenance and operating costs. Also, as it is possible to easily implement extreme conditions in which it is hard to conduct actual tests, it can prevent engine damages that may happen during the actual engine test under such conditions. In this study, an upgraded small jet engine performance test device was developed that can conduct both real and virtual engine test by applying real-time engine model to the existing micro jet engine performance test device that was previously developed by authors. This newly developed multi-purpose small jet engine performance test device is expected to be used for various educational and research purposes.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.891-894
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• 1999

According to increasing the integration of the device, there are important consideration about the improvement of the reliability in the product. To improve the reliability of the device, the test parameters and test time are increased. There are no pin-to-pin short test and pin-to-pin leakage test in the present test items to analysis the characteristics and reliability of the device. The purpose of the paper is to model the pin-to-pin phenomenon and propose to modify the test method present and to test the new pin-to-pin DC parameters. These modified and additive test items are applied to product test and confirmed to improve the reliability of product test.

• The Journal of Engineering Geology
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• v.26 no.1
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• pp.15-22
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• 2016

Hydraulic falling head and slug tests were carried out in an alluvium aquifer using a borehole stability device. The hydraulic testing had proved difficult in alluvial formations of sands and gravels due to borehole collapse and unstable borehole walls within the test section. This study aims to improve the hydraulic test results by using a borehole stability device. The device can minimize the collapse of borehole walls, and the use of a filter with a constant opening ratio improves the calculations per unit area of the test section. Permeability obtained from the falling head test without a borehole stability device was 8.82 × 10⁻⁵m/sec. When the borehole stability device was installed in the same test section the measured permeability increased to 4.00 × 10⁻⁴m/sec, which is 4.5 times that obtained without the borehole device. The relatively low permeability obtained using the conventional test method is attributed to the presence of a fine-grained slime generated during drilling and a reduction of the test area in the test interval due to a gradual collapse of the borehole walls. This study considers how the use of a borehole stability device to prevent borehole collapse can influence the results of hydraulic tests in alluvial formations. It is expected that the results can be used as a basis for improving the reliability and applicability of hydraulic tests performed in alluvial aquifers.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.11
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• pp.937-941
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• 2016

Stand-alone cervical cage consists of a PEEK body, Ti plate, and screw, which are configured as a single-piece. Through a single operation, this implantable medical device is capable of completely fixing the cervical vertebral body. For example, instead of a plate, which is normally used, the intervertebral disc is removed and replaced with a cervical cage. It should be noted that in Korea, KFDA guidelines for a stand-alone cervical cage have not yet been suggested. Therefore, the aim of this study is to present the systematic study of the static compression test, static torsion test, dynamic compression test, and expulsion test. Further, the test method is designed to refer to the ASTM standard and relative literature.