• 제목/요약/키워드: p chart

검색결과 387건 처리시간 0.03초

저수준 불량 공정의 개선을 위한 관리도 (A Control Chart for the Improvement of Low Defective Process)

  • 박기주
    • 산업경영시스템학회지
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    • 제21권45호
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    • pp.375-381
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    • 1998
  • For products that are subject to inspections that lead to either acceptance or rejection, the p chart or control chart for proportion defective is applicable. The charting technique approach to quality control aims at alerting its user to any presentations in the properties of a manufactured product. This article presents an important tool available for quality control of a production process at the occurrence of defects in manufactured products at view low levels to improve the efficiency of the manufacturing productivity and to satisfy customer through the reduction of defect rates. To understand the consequences of the level of quality on competitive position, a more technical perspective is needed.

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Numerical Switching Performances of Cumulative Sum Chart for Dispersion Matrix

  • Chang, Duk-Joon
    • 통합자연과학논문집
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    • 제12권3호
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    • pp.78-84
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    • 2019
  • In many cases, the quality of a product is determined by several correlated quality variables. Control charts have been used for a long time widely to control the production process and to quickly detect the assignable causes that may produce any deterioration in the quality of a product. Numerical switching performances of multivariate cumulative sum control chart for simultaneous monitoring all components in the dispersion matrix ${\Sigma}$ under multivariate normal process $N_p({\underline{\mu}},{\Sigma})$ are considered. Numerical performances were evaluated for various shifts of the values of variances and/or correlation coefficients in ${\Sigma}$. Our computational results show that if one wants to quick detect the small shifts in a process, CUSUM control chart with small reference value k is more efficient than large k in terms of average run length (ARL), average time to signal (ATS), average number of switches (ANSW).

Adjustment of Control Limits for Geometric Charts

  • Kim, Byung Jun;Lee, Jaeheon
    • Communications for Statistical Applications and Methods
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    • 제22권5호
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    • pp.519-530
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    • 2015
  • The geometric chart has proven more effective than Shewhart p or np charts to monitor the proportion nonconforming in high-quality processes. Implementing a geometric chart commonly requires the assumption that the in-control proportion nonconforming is known or accurately estimated. However, accurate parameter estimation is very difficult and may require a larger sample size than that available in practice in high-quality process where the proportion of nonconforming items is very small. Thus, the error in the parameter estimation increases and may lead to deterioration in the performance of the control chart if a sample size is inadequate. We suggest adjusting the control limits in order to improve the performance when a sample size is insufficient to estimate the parameter. We propose a linear function for the adjustment constant, which is a function of the sample size, the number of nonconforming items in a sample, and the false alarm rate. We also compare the performance of the geometric charts without and with adjustment using the expected value of the average run length (ARL) and the standard deviation of the ARL (SDARL).

광도차이에 따른 자주중산국수나무(Physocarpus opulifolius 'Diabolo') 와 자주맥문동(Ophiopogon planiscapus 'Nigrescens')의 엽색과 생육 변화 (Effect of Different Shading Levels on the Growth and Leaf Color Changes of Variegated Physocarpus opulifolius 'Diabolo' and Ophiopogon planiscapus 'Nigrescens')

  • 김현진;주나리
    • 한국환경복원기술학회지
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    • 제11권6호
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    • pp.112-119
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    • 2008
  • 본 연구는 자주중산국수나무와 자주맥문동의 광도변화에 따른 생육 및 생리 특성과 엽색발현을 조사하여 적정 광도를 구명하고자 한 결과는 다음과 같다. 1.자주색 잎이 특징인 중산국수나무(Physocarpus opulifolius 'Diabolo')는 차광에 따른 생육 변화를 관찰한 결과 40% 차광구에서 생육이 좋았으나 양지조건일 때 생리활성이 2배 이상 좋은 것으로 나타났다. 엽색발현은 0% 차광구에서 85% 차광구로 갈수록 진한 자주색(RHS colour chart 202A, dark grayish red)에서 녹색(RHS colour chart 139A, dark yellowish green)으로 변화되어 본래의 품종 특성인 엽의 색이 사라져 관상가치면에서 저하된 것으로 사료되어진다. 2.자주맥문동(Ophiopogon planiscapus 'Nigrescens')은 노지상태인 무차광구에서 생육이 가장 양호하였고, 관상가치면에서 생육활성이 좋은 대조구에서 선명한 자주색이 잘 나타났으며 더욱 진해진 검붉은색(RHS colour chart 202A, dark grayish)으로 엽색이 발현되었다.

경사모세관법에 의한 우의 적혈구침강 속도에 미치는 환경온도의 영향 (Effect of Ambient Temperature on Bovine Erythrocyte Sedimentation Rate as Measured by Angled Capillary Method)

  • 김경진;이방환
    • 한국임상수의학회지
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    • 제4권1호
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    • pp.395-401
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    • 1987
  • In this study, the effect of ambient temperature on the 45$^{\circ}$micro ESR/hr of cattle blood were observed, and a correction chart for correcting observed values at any ambient temperature to standard values at 20$^{\circ}C$ was plotted. Besides, the effect of storage temperature of blood on the 45$^{\circ}$micro ESR/hr was surveyed. The results were as follows: 1. The values of the 45$^{\circ}$micro ESR/hr were increased as the ambient temperature were elevated(P<0.01), and lower the value of PCV, higher the effect of temperature on the 45$^{\circ}$micro ESR/hr was observed(P<0.01). 2. Regression of values of 45$^{\circ}$micro ESR to ambient temperature in all the group of different level of blood PCV showed linear regression with the highly significant coefficient of correlation. With the results, correction chart was drawn as in Fig. 1. 3. In the purpose to verify the reliability of correction chart, observed values of 45$^{\circ}$micro ESR/hr in field(out door) were corrected to values at 20$^{\circ}C$ by the correction chart(Fig. 1), comparing with the observed values at 20$^{\circ}C$ of standard temperature. No significant differences were found between two groups mentioned above. 4. In the study on the effect of storage temperature of the blood on the 45$^{\circ}$micro ESR/hr, group of storage temperature at 5$^{\circ}C$ showed statistically no significant differences untill 24 hours in contrast with standard control group.

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영상 기반 pH 산도 측정 시스템 개발 (The development of pH reading system based on vision system)

  • 문하정;이동훈
    • 전기전자학회논문지
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    • 제17권4호
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    • pp.398-406
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    • 2013
  • 핵의학 영상 기기인 양전자 방출 단층 촬영 장치(Positron emission tomography: PET)와 같은 진단기기는 방사성의약품을 인체에 주입하여 질병을 진단한다. 이 때 사용되는 방사성의약품은 안전성을 위하여 적절한 수소 이온농도를 가져야 한다. 일반적으로 방사성 의약품의 수소 이온 농도를 측정하는 과정에서 흔히 사용되는 것이 pH시험지이다. 표본을 pH 시험지에 떨어뜨려 pH 시험지의 변색 정도를 표준색상표(Standard color chart)와 비교하여 표본의 pH를 알 수 있다. 그러나 이 방법은 측정자의 경험 정도에 따라 pH 측정값에 차이가 발생할 수 있다. 또한 pH 메타기는 고감도의 센서를 사용함으로 오염에 주의해야 한다. 이러한 불편함을 고려하여 쉽고 간단하게 정확한 pH를 측정하기 위한 새로운 장치 제작과 영상 기반 알고리즘을 통한 소프트웨어를 개발하였다. 이렇게 개발한 장치는 최종적으로 방사성의약품의 생산 시 품질관리(QC) 통합 제어 시스템으로 사용된다.

어패럴 CAD System의 활용화 방안 연구(II) - 테일러드 쟈켓 설계 과정을 중심으로 - (A Study on the Application of the Apparel CAD System(II))

  • 남윤자;이형숙;조영아
    • 한국의류학회지
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    • 제18권1호
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    • pp.43-56
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    • 1994
  • The Purpose of this study was to utilize of CAD System in pattern making process for women's apparel. The automation by the use of CAD System provides the higher accuracy and efficiency in pattern making process. AccuMark 300 System was used. for .this study. The results from this study were as follows . 1. New size spec chart and grading pitch chart were developed based on the data analysis and fitting tests for female college students. 2. New jacket block was developed based on the torso length sloper 3. Automatic grading of jacket block have been developed by creation and modification of grading rules of block pattern. 4. Pattern Design Systyem(P/D/S) were enabled to be constructed directly form a block pattern by modifications to existing styled pattern. 5. Original master pattern was generated by P/D/S menu option. 6. Production pattem added seam allowance, notchs was generated by P/D/S menu option. 7 Interative maker making process have enabled to save a wide range of time and space. 8. Measurement of garment by P/D/S measuring tools is to utilize in garment costing, quality control.

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