• Journal of Yeungnam Medical Science
• /
• v.38 no.2
• /
• pp.118-126
• /
• 2021

Background: This study is an analysis of evaluator factors affecting physician-patient interaction (PPI) scores in clinical performance examination (CPX). The purpose of this study was to investigate possible ways to increase the reliability of the CPX evaluation. Methods: The six-item Yeungnam University Scale (YUS), four-item analytic global rating scale (AGRS), and one-item holistic rating scale (HRS) were used to evaluate student performance in PPI. A total of 72 fourth-year students from Yeungnam University College of Medicine in Korea participated in the evaluation with 32 faculty and 16 standardized patient (SP) raters. The study then examined the differences in scores between types of scale, raters (SP vs. faculty), faculty specialty, evaluation experience, and level of fatigue as time passes. Results: There were significant differences between faculty and SP scores in all three scales and a significant correlation among raters' scores. Scores given by raters on items related to their specialty were lower than those given by raters on items out of their specialty. On the YUS and AGRS, there were significant differences based on the faculty's evaluation experience; scores by raters who had three to ten previous evaluation experiences were lower than others' scores. There were also significant differences among SP raters on all scales. The correlation between the YUS and AGRS/HRS declined significantly according to the length of evaluation time. Conclusion: In CPX, PPI score reliability was found to be significantly affected by the evaluator factors as well as the type of scale.

• Advances in aircraft and spacecraft science
• /
• v.5 no.2
• /
• pp.239-249
• /
• 2018

Physical tests are performed at various stages of the development cycle of a product, from prototype validation to product qualification. Although costly, there are growing demands for qualification tests like endurance vibration testing to be more representative of the real world. At the same time there are growing demands to assess the durability of these items based on FEA simulation. In this paper, we will explain how to set up a CAE-based test and how to correlate the results with some physical measurements. Specific assumptions will be explained and some advantages of using virtual tests will be highlighted such as the reduction of the number of prototypes needed, investigations on failures, evaluation of the level of reliability via sensitivity analysis, evaluation of the margins are at the end of a successful test. This presentation will therefore focus on explaining and showing how virtual tests can enrich the exploitation of physical tests.

• Journal of Ocean Engineering and Technology
• /
• v.10 no.2
• /
• pp.69-76
• /
• 1996

In-process quality control and high reliability of the weld are the major concerns in applying friction welding to the economical and qualified mass-production. Experimental examinations and quantitative analysis were performed for the optimiaztion of similar friction welding of hydraulic valve spool steels(SNCM220, SCM435, SACM645, SCM415, ${\varphi}24). The quantitative correlations were found between the initial cumulative counts of acoustic emission(AE) occurring during plastic deformation periods of the welding and the fatigue life as well as weld strength and welding conditions. A real-time evaluation system was developed for the friction weld quality by AE.

• Transactions of the KSME C: Technology and Education
• /
• v.5 no.2
• /
• pp.115-126
• /
• 2017

This paper proposes an accelerated life evaluation of drive shaft for the power train parts of special purpose vehicle. It is necessary the real load data of usage level driving load condition for life evaluation of power train parts, but we can't get the load spectrum data for evaluation in many case of special purpose vehicle. So, in this paper, the road load spectrum data for evaluation is created by modeling and simulation based on vehicle data and special road condition. The inverse power model is used for accelerated life test. The equivalent torque of load spectrum is achieved using the Miner's Rule. This paper also proposes the calibrated acceleration life test method for drive shaft. The fatigue test is performed through three stress levels. The lifetime at normal stress level is predicted by extrapolation, and is verified through comparison of experimental results and load spectrum data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11b
• /
• pp.204-207
• /
• 2005

A reliable and practical finite element modeling technique to predict the lifetime of automotive electronics is important for engineers in reliability. In reliability evaluation on the automotive electronics, most studies rarely used FE model verification process. The material properties and boundary conditions are very important factors in this process to assure the reliability of the automotive electronics. This study aims to develop a better and more accurate FE model in order to predict fatigue life of the automotive electronics using Virtual Qualification lifetime assessment techniques. After conducting the modal analysis by the experiments to grasp a system characteristic, this paper presents material properties and boundary conditions that is obtained by the comparisons of FEA simulation results using DOE technique and the experiment results.

• Korean Chemical Engineering Research
• /
• v.62 no.4
• /
• pp.355-363
• /
• 2024

Although copolymer aramid is a fiber with excellent flexural performance, there is no test method to evaluate flexural fatigue performance. Various studies are currently being conducted in korea to develop copolymer aramid, and in order to develop the reliability of aramid fibers to a global level, it is necessary to develop a test method to evaluate the flexural fatigue performance of aramid fibers. In this study, we developed an test equipment and test method that can evaluate the flexural fatigue performance of copolymer aramid and analyzed the flexural fatigue performance of aramid fiber. Flexing rollers are made of ceramic materials and rotating shapes to minimize friction. The diameter of the roller was set to 10 mm by calculating the minimum allowable curvature. The B₁₀ life was calculated through a flexural fatigue test, and the para-aramid was 125,770 cycles, the copolymer aramid was 598,150 cycles, and the aramid nano fiber(ANF) coated copolymer aramid was 589,073 cycles. Through the S-N diagram, the fatigue life relationship according to the load change was confirmed. copolymer aramid fibers exhibit better flexural fatigue performance than para-aramid fibers at high loads. The ANF coated copolymer aramid also exhibits excellent flexural fatigue performance.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.8
• /
• pp.721-728
• /
• 2017

High-grade gray cast iron (HCI350) was prepared by adding Cr, Mo and Cu to the gray cast iron (GC300). Their microstructure, mechanical properties and fatigue strength were studied. Cast iron was made from round bar and plate-type castings, and was cut and polished to measure the percentage of each microstructure. The size of flake graphite decreased due to additives, while the structure of high density pearlite increased in volume percentage improving the tensile strength and fatigue strength. Based on the fatigue life data obtained from the fatigue test results, the probability - stress - life (P-S-N) curve was calculated using the 2-parameter Weibull distribution to which the maximum likelihood method was applied. The P-S-N curve showed that the fatigue strength of HCI350 was significantly improved and the dispersion of life data was lower than that of GC300. However, the fatigue life according to fatigue stress alleviation increased further. Data for reliability life design was presented by quantitatively showing the allowable stress value for the required life cycle number using the calculated P-S-N curve.

• Journal of Oriental Neuropsychiatry
• /
• v.20 no.4
• /
• pp.1-13
• /
• 2009

Objectives : As depression falls into the category of Wuljeung, Gamiguibi-Tang(Jiaweiguipitang) is the standard prescription to cure Wuljeung. This study develops a questionnaire for building the guidelines to administer Gamiguibi-Tang to depression and evaluates reliability and validity of questionnaire. Methods : With extracting the text related to depression and Gamiguibi-Tang through total 9 Korean medicine books and consulting the experts, the study selected 80 items and converted them into a questionnaire. It surveyed the neuropsychiatry professors and the medical specialists three times by Delphi method, and lastly selected 21 final items of a questionnaire. On the basis of the questionnaire, it collected total 216 samples and tested their reliability and validity. Results : 21 items all didn't reduce total Cronbach alpha coefficient and satisfied test-retest reliability. As a result of factor analysis, totally 5 factors were extracted such as mental state, sleep, accompaniment, fatigue and weakness. Finally, in comparing a depression group with a normal control group, two groups all showed meaningful difference in each 21 items' point, the sum of factor 1 to 5 items' points, and the sum of 21 items' points. Conclusions : The questionnaire on the updated depression prescription guideline of Gamiguibi-Tang satisfied both of reliability and validity. Later it can help objectifying to apply Gamiguibi-Tang to depression cure.

• Journal of Sensor Science and Technology
• /
• v.33 no.2
• /
• pp.86-92
• /
• 2024

Flexible electronic devices are exposed to repeated mechanical deformation; therefore, electrode performance is an important element. Recently, a new technology has been developed to improve the adhesion strength between polymer substrates and metal thin films through the cross-linking reaction of bovine serum albumin (BSA) bioconjugation proteins; however, additional performance evaluation as an electrode is necessary. Therefore, in this study, we investigated the effect of adhesive strength between a flexible substrate and a metal thin film on the performance of a flexible electrode. Cracks and changes in the electrical resistance of the electrode surface were observed through outer bending fatigue tests and tensile tests. As a result of a bending fatigue test of 50,000 cycles and a tensile test at 10% strain, the change in the electrical resistance of the flexible electrode with a high adhesion strength was less than 40%, and only a few microcracks were formed on the surface; thus, the electrical performance did not significantly deteriorate. Through this study, the relationship between the adhesion strength and electrical performance was identified. This study will provide useful information for analyzing the performance of flexible electrodes in the commercialization of flexible electronic devices in the future.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.45 no.6
• /
• pp.498-507
• /
• 2017

Electronic equipments comprised of high density components with various packaging types have been recently applied to a satellite. Therefore, to guarantee high reliability of electrical equipment, a design approach, which can reduce the development period and cost through an early diagnosis in potential risks of failure, should be established. In the previous research, the reliability assesment of the electronic equipments have based on Steinberg's fatigue failure theory. However, this theory was not enough for further investigation of life prediction and reliability of the electronic equipments comprised of various sizes and packaging types due to its theoretical limitations and analysis results sensitivity with regard to different modeling technic. In that case, if detailed finite element model is established, aforementioned problems can be readily solved. However, this approach might arise disadvantage of spending much time. In this paper, to establish strategy for high reliability design of electronic equipment, we performed mechanical reliability evaluation of CCB (Camera Controller Box) at qualification level based on the approach using Sherlock unlike design techniques applied to existing business.