• Journal of Korean Society for Quality Management
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• v.43 no.4
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• pp.589-606
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• 2015

Purpose: In developing new products, reducing performance variation is important for competitiveness factors such as quality, cost, and delivery. This paper aims at evaluating three performance variations; measurement, performance evaluation, and manufacturing variations, and then improving product and process design, focused on paper helicopter making case study. Methods: For measurement system analysis, gage R&R (repeatability and reproducibility), linearity, stability are evaluated. Since gage R&R are not satisfactory, the measurement system is improved by adopting voice memos application of iPhone and providing standard measurement procedure. To evaluate performance variation, product deterioration and environment factor (wind speed) is considered. Since the existing design is sensitive to these noise factors, a new product design is developed, which is proven to be robust to the noise factors. Finally, manufacturing variations are evaluated with five factors which can cause variation in flight time. To reduce the impact of three significant factors, three improvement methods are applied. Results: Three performance variations are evaluated and robust paper helicopter design is presented. Conclusion: To reduce measurement and process variations, improved measurement method and paper helicopter making procedure are proposed. A new product design is also presented which is robust to deterioration and environmental variation. This paper is expected to benefit students and practitioners who want to have hands-on knowledge on new product quality improvement.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.10 no.1
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• pp.78-97
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• 2006

Background: There was seldom study about method that estimate expertness of pulse diagnosis in 8 Constitution Medicine in spite of the diagnostician importance in 8 Constitution Medicine Objectives: This study is to evaluate diagnostician's consistency and accuracy about pulse diagnosis in 8 Constitution Medicine using Cage R&R study. Methods: The subjects were comprised of 28 volunteers. Among theme, 3 diagnosticians and 10 participants were chosen through questionnaire. Diagnosticians diagnosed participant's Constitution by pulse diagnosis in 8 Constitution Medicine with hiding their eyes by eyepatch. MINITAB statistical software(ver. 13.20) was used for statistical analysis: Attribute Cage R&R study was used to verify the results. Results: 1. In the measurements of consistency, diagnostician b(agreement=80%, Value of k=0.8276)was very good, diagnostician a(agreement=70%, Value of k=0.7465) was good, and diagnostician c(agreement=50%, Value of k=0.5365) was moderate. 2. In the measurements of accuracy, diagnostician b(agreement =70%, Value of t=0.6812) was good, diagnostician a(agreement=60%. Value of t=0.6414) was good, and diagno-stician c(agreement=0%, Value of k=-0.1000) was poor. 3. In cofidence of diagnosis, diagnostician c was 75%, diagnostician a was 70%, and diagnostician b was 64%. Conclusion: The results suggest that diagnostician's consistency and accuracy about pulse diagnosis in 8 Constitution Medicine can be evaluated by Cage R&R study. further study is needed for estimation method of pulse diagnosis in 8 Constitution Medicine.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.9 no.2
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• pp.123-144
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• 2005

Objectives: Pulse-Respiration Ratio has been used for estimating subject's Han-Yeol [寒熱] status since it mentioned in suwen [素問]. In practicing Pulse-Respiration Ratio over 5 means the status of Yeol [熱], Pulse-Respiration Ratio below 3 means the status of Han [寒]. We performed this study to examine the Optimum Standard for Measuring Pulse-Respiration Ratio on the Basis of Repeatability and Reproducibility. Methods: After subject's 5 minutes rest we measured subject's ECG, respiration pattern, EEG, EMG simultaneously. In this research examiner's number is two, subject's number is four, and the number of repeat is two. We calculated Pulse-Respiration Ratio through dividing Respiration cycle average by Pulse cycle average according to each standard including time section, $EEG(relative-{\alpha}$ density, $relative-{\beta}$ density, ${\alpha}/{\beta}$ and EMG. We analyzed these data through Gage R&R study using MINITAB 13.20 program and considered the results of below 30 %R&R and over 4 Number of Distinct Categories to have a significance. Results: 1. In the applying of time standard, Pulse-Respiration Ratio from section 3, 4, 6, 8 had a significant meaning in the aspect of Repeatability and Reproducibility. 2. In the applying of $EEG({\alpha}$ I , ${\beta}$ I , ${\alpha}/{\beta})$, EMG(E I) standard, there was no significant results. 3. In the applying of time standard(section 5, 6, 7), $EEG({\alpha}$ I , ${\beta}$ I , ${\alpha}/{\beta})$ and EMG(E I) standard simultaneously, Pulse-Respiration Ratio from ${\alpha}/{\beta}$ in section 6, ${\beta}$ I in section 8 had a significant meaning in the aspect of Repeatability and Reproducibility. Conclusions: We can suggest the Optimum Standard for Measuring Pulse-Respiration Ratio on the basis of Repeatability and Reproducibility as followings; 1. Pulse-Respiration Ratio Measuring time should be at least 15 minutes. 2. Applying of time(section 6, 8) and $EEG({\beta}$ I, ${\alpha}/{\beta})$ standard simultaneously is recommended considering reliability and validity but more study is needed. 3. EMG(E I) may be helpful to detect the segment of physical rest and exclude artifacts but more study is needed.

• Journal of Korean Society for Quality Management
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• v.42 no.4
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• pp.607-616
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• 2014

Purpose: This paper reviews popular measurement system indices and proposes a procedure for assessing a measurement system using two parameters with intraclass correlation and a factor for process capability. Methods: Gage Repeatability and Reproducibility(GR&R), precision-to-tolerance ratio(PTR), number of distinct categories, producer's and consumer's risks are employed to assess the measurement capabilities and discuss the relationships between measurement system metrics. Results: Two-dimensional plot by two parameters is presented to assess adequacy of the measurement system and process capability. A numerical example and previously studied case study are provided for illustration. Conclusion: The procedure proposed in this paper using two-dimension parameters provides a valuable procedure and helpful guidelines to quality and production managers in assessing the capabilities of a measurement system and choosing the needed actions to be the most benefit.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.2
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• pp.208-214
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• 1986

To establish the evaluation of the fatigue crack growth behavior in 5083-O aluminum alloy, constant load-amplitude fatigue crack growth tests were carried out under the small scale yielding conditions. Crack length and closure of this material were measured by the compliance method using a clip-on gage. The main results obtained as follows: The fatigue crack growth rate against stress intensity factor range .DELTA.K exhibits the trilinear form with two transitions at the growth rate 5.5*10$^{-6}$ and 5.5*10$^{-5}$ mm/cycle, in the so-caled Region II. The trilinear form appears still in the plot of growth rate versus effective stress intensity factor range .DELTA. $K_{eff}$. Stress ratio R affects the relationship of crack growth rates versus .DELTA.K but does not affect the reation of crack growth rate versus .DELTA. $K_{eff}$. The experimental results indicate that the effective stress intensity range ratio U depends on the maximum stress intensity factor $K_{max}$, but not on the stress ratio R.o R.R.

• Korean Journal of Agricultural Science
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• v.11 no.1
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• pp.160-175
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• 1984

This study was carried out to analyze the effects of the revolution and forwarding speed of the rotary blade and the edge curves which were $30^{\circ}$ and $40^{\circ}$, on the power requirement of rotary tillage. In this study, the revolutions of the rotary blade considered were 204, 243, 285, 360 rpm, and the forwarding speeds of the rotary system considered were 29.40cm/sec, 46.93em/sec. The power requirements of rotary blade were measured by a dynamic strain gage systems at the soil bin which was filled with artificial soil. The results of the study were summarized as follows: 1. The response surface analysis showed that the revolution and forwarding speed of the rotary shaft had an interacting influence on the torque requirement of the rotary blade. The mathematical model developed by the above was repersented as follow. $$T=a_0+a_1V+a_2R +a_3VR+a_4VR^2$$ where, $a_0=constant$ $a_1,\;a_2,\;a_3,\;a_4=coefficients$ V=forwarding speed of the rotary system. (em/sec) R=revolution of the rotary shaft. (rpm) T=tilling torque requirement. (kg-m) 2. When the maximum tilling torque requirement was analyzed, ${\partial}T/{\partial}R$ was decreased with the increasing revolution of rotary shaft, while ${\partial}T/{\partial}V$ was increased, which was minimum at 200~220 rpm. When the forwarding speeds were increased, ${\partial}T/{\partial}R$ was decreased with increasing rate. 3. When the mean tilling torque requirement was analyzed, ${\partial}T/{\partial}V$ was constant at 320~360 rpm and ${\partial}T/{\partial}R$ was decreased with increasing rate along with the increasing revolution of rotary shaft. 4. When the mean tilling torgue requirement per unit volume of soil was analyzed, ${\partial}T/{\partial}V$ was minimum at 270~300 rpm. ${\partial}T/{\partial}R$ for the forwarding speeds of 29.40cm/sec and 46.93cm/sec was same as that for 280~290 rpm. 5. Increasing the edge curves of the rotary blades, the tilling torque requirement was increased. But other studies showed that the smaller the edge curve, the more straw could be wrapped on blades which resulted in increasing torque requirements. Therefore, the edge curve of rotary blade should be considered for the future study.

• Journal of the Korea Safety Management & Science
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• v.11 no.2
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• pp.117-126
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• 2009

We develop methods for propagating and analyzing EPCI(Extended Process Capability Index) by using the error type that classifies into accuracy and precision. EPCI developed in this study can be applied to the three combined processes that consist of production, measurement and calibration. Little calibration work discusses while a great deal has been studied about SPC(Statistical Process Contol) and MSA(Measurement System Analysis). EPCI can be decomposed into three indexes such as PPCI(Production Process Capability Index), PPPI(Production Process Performance Index), MPCI(Measurement PCD, and CPCI(Calibration PCI). These indexs based on the type of error classification can be used with various statistical techniques and principles such as SPC control charts, ANOVA(Analysis of Variance), MSA Gage R&R, Additivity-of-Variance, and RSSM(Root Sum of Square Method). As the method proposed is simple, any engineer in charge of SPC. MSA and calibration can use efficientily in industries. Numerical examples are presentsed. We recommed that the indexes can be used in conjunction with evaluation criteria.

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.365-366
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• 2007

Micro jetting drop inspection system is essential to measuring micro drop volume. Measuring pico-liter drop volume is useful for new LCD color filter product process that is based on inkjet printing technology. To upgrade the reliability in drop measurement system, we use the auto focusing & multi drop reiteration & blurring average algorism. First of all we used standard mark for gage R&R in the vision system. Finding the most suitable threshold for multi blurring drop, is the main key of this research. Sensitivity of vision system is a standard in measuring the upgrade system level. So, suitable threshold can upgrade the performance of jetting drop inspection system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.2
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• pp.143-147
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• 2017

In this study, a driving load measuring method has developed without utilizing WFT. To measure the driving load, we developed a three-axis load cell with a strain gage. A method to verify the performance of load cells was developed. A system to measure the input load was proposed, and it was verified by evaluation. The measurement error of the impact road surface was found to be less than 20％. However, except under impact road surface conditions, the proposed system can be applied for actual vehicle input load measurement. The influence of tire evaluation tests were carried out through the handling verification evaluation. The input load measurement methods proposed in the present study make performance verification possible without using WFT.

• Proceedings of the Korean Reliability Society Conference
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• 2004.07a
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• pp.249-261
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• 2004

Many of companies all over the world have been certified ISO 9000 which is customer focused since last ten 10 years, and industrial sector specific certifications have been developed, such as QS-9000 and ISO/TS 16949 which are specific requirements added to ISO 9000 for the automotive industrial sector. Requirements addressed in ISO 9000, QS-9000 and ISO/TS 16949 are considered to be significant. And I think that requirements for reliability elements such as Design FMEA, Process FMEA and Gage R＆R are very important. I sincerely hope that my study for requirements for reliability elements to be helpful to individual, companies and related association. There should be a lot of requirements in related with reliability in other industrial sectors and I am planning to study on it continuously.