• 품질경영학회지
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• 제30권4호
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• pp.106-119
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• 2002

The fatigue curve with estimated parameters represents the estimate of the median or mean life at a given applied stress But, in order to assist a designer in making decisions regarding the fatigue failure mode, it is common practice to construct a design curve on the lower or safe side of data. In this study, to overcome the limitations(i.e., no runout, equal variance, and quality of the approximation, etc) of Shen, Wirsching, and Cashman's method which suggested the approximate design curve for nonlinear models using tolerance interval constructed by Owen's method, an algorithm to find design curves under the fatigue model using a parametric bootstrap method, is proposed and illustrated with multiple fatigue data sets.

• Molecules and Cells
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• 제21권2호
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• pp.192-196
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• 2006

Salt tolerance was evaluated at the young seedling stage of rice (Oryza sativa L.) using recombinant inbred lines (MG RILs) from a cross between Milyang 23 (japonica/indica) and Gihobyeo (japonica). 22 of 164 MG RILs were classified as tolerant with visual scores of 3.5-5.0 in 0.7% NaCl. Interval mapping of QTLs related to salt tolerance was conducted on the basis of the visual scores at the young seedling stage. Two QTLs, qST1 and qST3, conferring salt tolerance, were detected on chromosome 1 and 3, respectively, and the total phenotypic variance explained by the two QTLs was 36.9% in the MG RIL population. qST1 was the major QTL explaining 27.8% of the total phenotypic variation. qST1 was flanked by Est12~RZ569A, and qST3 was flanked by RG179~RZ596. The detection of new QTLs associated with salt tolerance will provide important information for the functional analysis of rice salt tolerance.

• 품질경영학회지
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• 제30권1호
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• pp.97-117
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• 2002

We apply Taguchi method to the process optimization problem of chemical reaction process, and some case studies are done to find out the way for cost reduction and quality improvement The parameter and tolerance designs of Taguchi mettled are done with operation data of a chemical process and we propose a procedure how to use and analyze the operation data to find the optimal process conditions and tolerance limits. In order to use the continuous values in experiment conditions, it is suggested how to determine the interval of each level by discrete values and to treat any missing values caused from discrete 4 levels.

• 산업경영시스템학회지
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• 제30권2호
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• pp.37-43
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• 2007

ANOVA is widely used for measurement system analysis. It assumes that the measurement error is normally distributed, which may not be seen in certain industrial cases. In this study, the exact and bootstrap confidence intervals for precision-to-tolerance ratio (PTR) are obtained for the cases where the measurement errors are normally and non-normally distributed and the reproducibility variation can be ignored. Lognormal and gamma distributions are considered for non-normal measurement errors. It is assumed that the quality characteristics have the same distributions of the measurement errors. Three different bootstrap methods of SB (Standard Bootstrap), PB (Percentile Bootstrap), and BCPB (Biased-Corrected Percentile Bootstrap) are used to obtain bootstrap confidence intervals for PTR. Based on a coverage proportion of PTR, a comparative study of exact and bootstrap methods is performed. Simulation results show that, for non-normal measurement error cases, the bootstrap methods of SB and BCPB are superior to the exact one.

• 품질경영학회지
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• 제47권3호
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• pp.523-535
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• 2019

Purpose: We research on the efficient response surface methodology(RSM) design to develop a design space in Quality by Design(QbD). We propose practical designs for the successful construction of the design space in QbD by allowing different number of replicates at the box points, star points, and the center point in the rotatable central composite design(CCD). Methods: The fraction of design space(FDS) plot is used to compare designs efficiency. The FDS plot shows the fraction of the design space over which the relative standard error of predicted mean response lies below a given value. We search for practical designs whose minimal half-width of the tolerance interval per a standard deviation is less than 4.5 at 0.8 fraction of the design space. Results: The practical designs for the number of factors between two and five are listed. One of the designs in the list could be chosen depending on the experimental budget restriction. Conclusion: The designs with box points replications are more efficient than those with the star points replication. The sequential method to establish a design space is illustrated with the simulated data based on the two examples in RSM.

• 한국산림과학회지
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• 제99권1호
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• pp.47-51
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• 2010

본 연구의 목적은 일회성 산림 걷기 운동이 내당능장애(impaired glucose tolerance, IGT)와 인슐린 비의존성 당뇨병(non-insulin-dependent diabetes mellitus, NIDDM)환자의 혈당치 변화에 어떠한 영향을 미치는 가를 알아보기 위한 것이었다. 연구의 대상자는 노인 여성(n=60)을 IGT 산림 걷기 운동군(n=15; $66.21{\pm}4.16$ yrs), NIDDM 산림 걷기 운동군(n=15; $64.85{\pm}3.23$ yrs), IGT 운동장 걷기 운동군(n=15; $67.44{\pm}1.78$ yrs), NIDDM 운동장 걷기 운동군(n=15; $65.55{\pm}8.21$ yrs)으로 구분하여 운동강도 HRmax 50~60%의 산림 걷기 운동(인터벌+저항성 근육운동)과 운동장 걷기 운동(유산소성 운동) 프로그램을 적용하여 운동 전과 후에 혈당을 측정하여 분석하였다. 그 결과, 첫째 내당능장애군에서 산림 걷기와 운동장 걷기 집단은 운동 후에 모두 유의한 수준에서 혈당치의 감소를 보였고, 둘째 인슐린 비의존성 당뇨병군에서 산림 걷기 집단은 운동 후에 혈당치가 유의하게 감소되었지만 운동장 걷기 집단은 특별한 혈당치의 변화가 없었다. 따라서 본 연구는 유산소 운동으로 지속적으로 운동장을 걷는 운동보다 오르막 내리막 지형을 이용한 인터벌 운동과 저항성 근육운동의 복합 형태인 산림 걷기 운동이 내당능장애와 인슐린 비의존성 당뇨병 환자에 더 효과적인 것으로 제안한다.

• 제어로봇시스템학회논문지
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• 제15권7호
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• pp.753-759
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• 2009

As many systems depend on electronics in an intelligent vehicle, concern for fault tolerance is growing rapidly. For example, a car with its braking controlled by electronics and no mechanical linkage from brake pedal to calipers of front tires(brake-by-wire system) should be fault tolerant because a failure can come without any warning and its effect is devastating. In general, fault tolerance is usually designed by placing redundant components that duplicate the functions of the original module. In this way a fault can be isolated, and safe operation is guaranteed by replacing the faulty module with its redundant and normal module within a predefined interval. In order to make in-vehicle network fault tolerant, this paper presents the concept and design methodology of an IEEE 1451 based dual CAN module. In addition, feasibility of the dual CAN network was evaluated by implementing the dual CAN module.

• Architectural research
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• 제9권1호
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• pp.31-37
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• 2007

This study presents the so-called Modified Allowable Stress Design (MASD) method for structural designs. The objective of this study is to qualitatively estimate uncertainties of tensile steel member's cross-sectional structural designs and find the optimal resulting design which can resist all uncertainty cases. The design parameters are assumed to be interval associated with lower and upper bounds and consequently interval methods are implemented to non-stochastically produce design results including the structural uncertainties. By seeking optimal uncertainty combinations among interval parameters, engineers can qualitatively describe uncertain design solutions which were not considered in conventional structural designs. Under the assumption that structures have basically uncertainties like displacement responses, the safety range of resulting designs is represented by lower and upper bounds depending on given tolerance error and structural parameters. As a numerical example uncertain cross-sectional areas of members that can resist applied loads are investigated and it demonstrates that the present design method is superior to conventional allowable stress designs (ASD) with respect to a reliably structural safety as well as an economical material.

• Journal of Oral Medicine and Pain
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• 제20권1호
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• pp.97-103
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• 1995

The purpose of this study was to evaluate the effect of experimenter gender on pain report as well as the sex differences in pain threshold and pain tolerance. Cold pressor test and pressure pain threshold (PPT) test were performed on forty dental students by both of a male and a female experimenter separately with 1 day interval. The obtained results were as follows : There were no differences in pain threshold and pain tolerance between males and females when they were examined by the same gender experimenter in the cold pressor test, but when they were examined by the opposite gender experimenter the pain threshold of males was significantly higher than females. When the pain threshold was measured by the same gender experimenter, using a algometer, there was no differences in PPT between males and females. However, when the same measurements were done by the opposite gender experimenter, the PPT of males was significantly higher than females at anterior temporalis and inferior masseter. For cold pressor test, females tended to report lower levels of pain threshold and pain tolerance to a male experimenter than a female, but the differences were not significant. Although both pain threshold and pain tolerance were increased when males were examined by a female experimenter in the cold pressor test, the statistical significance was found only in pain tolerance. When subjects were examined by the opposite gender experimenter in the PPT text, females reported significantly higher levels of pain at inferior masseter and males reported significantly lower levels of pain at anterior temporalis and inferior masseter.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1749-1752
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• 2005

High speed machining has become the main issue of metal cutting. Due to increase of the rotational speed of the spindle, problems, such as the run-out errors, reduced stiffness, must be overcome to improve the machining accuracy. In order to solve the problems, it is important to determine the appropriate clamping unit and tooling system. This paper presents an investigation into an evaluation of contact interval which is the interface between spindle taper hole and tool holder shank of the spindle. Finite element analysis is performed by using a commercial code ANSYS according to variation of clamping forces and rotational speeds. This paper proposed fit tolerance in order to evaluate the effects of clamping force and rotational speed on the contact interval in the spindle interface. From the finite element results, it has been shown that the rotational speed rather than clamping force mostly influence on the variation of the contact interval.