• 제목/요약/키워드: Standard variation

검색결과 1,552건 처리시간 0.024초

군간-군내-부품내 변동을 고려한 Gage R&R 분석에 관한 연구 (A Study of Gage R&R Analysis Considering the Variations of Between-Within Group and Within Part)

  • 이승훈;이창우
    • 산업공학
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    • 제18권4호
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    • pp.444-453
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    • 2005
  • The purpose of the Gage R&R study is to determine whether a measurement system is adequate for monitoring a process. If the measurement system variation is small relative to the process variation, then the measurement system is deemed "adequate". The sources of variation associated with the measurement system are compared using an analysis of variance (ANOVA) model, in general. A typical ANOVA model used in a standard Gage R&R study is the two-factor random effect model. Then, the ANOVA partitions the total variation into three categories: repeatability, reproducibility, part variation. However, if the process variation possesses the between group variation, within group variation, and within part variation, these variations can cause the measurement system evaluation to provide misleading results. That is, in the standard Gage R&R study these variations affect the estimate of repeatability, reproducibility, or both. This paper presents a four-factor nested factorial ANOVA model which explicitly considers these variations for the Gage R&R study. The variance component estimators are derived by setting the EMS equations equal to the corresponding mean square from the ANOVA table and solving. And the proposed model is compared with the standard Gage R&R model.

생산현장에서 발생하는 불확실성을 고려한 생산통제기법들의 유용성 분석

  • 이장한;박진우
    • 한국경영과학회:학술대회논문집
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    • 한국경영과학회 1993년도 추계학술대회발표논문집; 서강대학교, 서울; 25 Sep. 1993
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    • pp.185-190
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    • 1993
  • In this paper, we investigate the effect of production uncertainty - especially demand fluctuation and activity time variation, to production control policies. First, we examine three famous production control policies, namely, MRP, JIT, OPT, from shop floor control perspective and analyze the difference among them. Based on these, simulation studies are performed to draw out the effects of demand fluctuation which are classified into demand lumpiness and demand irregularity, and, the effects of activity time variation which are classified into standard time variation and non-standard time variation. Experimental investigation shows that, in terms of demand fluctuations, MRP is affected by demand lumpiness, but JIT by demand irregularity. And we also see that both MRP and JIT are influenced by standard time variation with respect to activity time variations.

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군간-군내-부품내 변동을 고려한 Gage R&R 분석에 관한 연구 (A Study of Gage R&R Analysis Considering the Variations of Between-Within Group and Within Part)

  • 이승훈;이창우
    • 한국경영과학회:학술대회논문집
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    • 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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    • pp.975-982
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    • 2005
  • The purpose of the Gage R&R study is to determine whether a measurement system is adequate for monitoring a process. If the measurement system variation is small relative to the process variation, then the measurement system is deemed 'adequate'. The sources of variation associated with the measurement system are compared using an analysis of variance (ANOVA) model, in general. A typical ANOVA model used in a standard Gage R&R study is the two-factor random effect model. Then, the ANOVA partitions the total variation into three categories: repeatability, reproducibility, part variation. However, if the process variation possesses the between group variation, within group variation, and within-part variation, these variations can cause the measurement system evaluation to provide misleading results. That is, in the standard Gage R&R study these variations affect the estimate of repeatability, reproducibility, or both. This paper presents a four-factor nested factorial ANOVA model which explicitly considers these variations for the Gage R&R study. The variance component estimates are derived by setting the EMS equations equal to the corresponding mean square from the ANOVA table and solving. And the proposed model is compared with the standard Gage R&R model.

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하천 유량.수질변화 특성을 고려한 수질오염총량관리 기준유량 조건에 관한 연구 (A Study on the Suggestions for Standard Flow Conditions considering the Variation of Stream Flow and Water Quality for the Management of Total Maximum Daily Loads)

  • 박준대;오승영;최윤호
    • 한국물환경학회지
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    • 제28권3호
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    • pp.426-435
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    • 2012
  • The variation of stream flow is the one of the most important factors which influence on that of water quality in the unit watershed. The target water quality goal is established and permissible load is allotted in the base of the standard flow condition along with its water quality for the management of Total Maximum Daily Loads (TMDLs). A standard flow selected could cause problems in the load allotment if it was not properly arranged. This study reviewed the acquisition of water quality data, the self-variation and the retainability in water quality on the specific flow conditions. This study also proposed the median and the adjusted average flow condition out of general flow conditions as alternative standard flow conditions. It is considered that the alternatives can make the water quality data easily acquired and the water quality representativeness more enhanced on the standard flow conditions.

공압밸브의 동적응답 특성측정 자동화 시스템 개발 (Development of automatic measurement system for dynamic respose time of pneumatic solenoid valve)

  • 강보식;김형의
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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    • pp.974-978
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    • 1991
  • Electro-pneumatic valve is an electro-mechanical device which converts electric signal into pneumatic flow mu or pressure. A measurement of dynamic response time is very important to evaluate valve performance. Dynamic response time of electro-pneumatic valve has a variation accordance with valve types, operating way and test standard. In this study, automatic measurement system of dynamic response time is composed based on test condition of dynamic response time test standard(CETOP, JIS). Also, in this study test pressure variation characteristics accordance with variation of solenoid excitation power, and we developed dynamic response measurement system enable to compare of and analyze these two characteristics.

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CCD PHOTOMETRY OF STANDARD STARS AT MAIDANAK ASTRONOMICAL OBSERVATORY IN UZBEKSTAN: TRANSFORMATIONS AND COMPARISONS

  • Lim, Beomdu;Sung, Hwan-Kyung;Bessell, M.S.;Karimov, R.;Ibrahimov, M.
    • 천문학회지
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    • 제42권6호
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    • pp.161-174
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    • 2009
  • Observation of standard stars is of crucial importance in stellar photometry. We have studied the standard transformation relations of the UBV RI CCD photometric system at the Maidanak Astronomical Observatory in Uzbekistan. All observations were made with the AZT-22 1.5m telescope, SITe 2k CCD or Fairchild 486 CCD, and standard Bessell UBV RI filters from 2003 August to 2007 September. We observed many standard stars around the celestial equator observed by SAAO astronomers. The atmospheric extinction coefficients, photometric zero points, and time variation of photometric zero points of each night were determined. Secondary extinction coefficients and photometric zero points were very stable, while primary extinction coefficients showed a distinct seasonal variation. We also determined the transformation coefficients for each filter. For B, V, R, and I filters, the transformation to the SAAO standard system could be achieved with a straight line or a combination of two straight lines. However, in the case of the U filter and Fairchild 486 CCD combination, a significant non-linear correction term - related to the size of Balmer jump or the strength of the Balmer lines - of up to 0:08 mags was required. We found that our data matched well the SAAO photometry in V, B - V, V - I, and R - I. But in U - B, the difference in zero point was about 3.6 mmag and the scatter was about 0.02 mag. We attribute the relatively large scatter in U -B to the larger error in U of the SAAO photometry. We confirm the mostly small differences between the SAAO standard UBV RI system and the Landolt standard system. We also attempted to interpret the seasonal variation of the atmospheric extinction coefficients in the context of scattering sources in the earth's atmosphere.

해상교통조사 관측일수에 관한 연구 (A Study on the Observation Days of Maritime Traffic Investigation)

  • 유상록;박성북;박영수;정재용
    • 해양환경안전학회지
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    • 제21권4호
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    • pp.397-402
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    • 2015
  • 본 연구는 관측일수에 따른 교통량의 신뢰성을 검증하고자 한다. 목포항의 1년간 선박자동식별장치(AIS) 자료를 사용하여 월별, 요일별, 시간별 변화지수를 비교한 후, 각 관측일수에 따른 최대표준오차를 산출하였다. 월별변화지수를 비교한 결과 9월달 1.11, 2월달 0.84로 나타나 9월달이 2월달 교통량 보다 약 32.1 % 많은 것으로 나타났다. 요일변화지수는 화요일 1.05, 일요일 0.92로 나타나 화요일이 일요일 교통량보다 약 14.1 % 많았다. 해상교통조사는 요일변화지수를 고려하여 최소 1주일 이상 실시하면 최대표준오차를 21 % 이내로 산출할 수 있다. 따라서 해상교통조사 관측시기에 따라 각 변화지수를 적용하여 교통량의 흐름을 반영한 연구가 뒷받침 되어야 하겠다.

석유생산 시 유동안정성 확보를 위한 불투명 오일의 왁스생성온도 결정 연구 (Experiment Research for Wax Appearance Temperature Determination of Opaque Oil)

  • 강판상;황순혜;손비룡;임종세
    • 에너지공학
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    • 제24권2호
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    • pp.1-8
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    • 2015
  • 석유의 생산 과정에서 발생하는 왁스(wax)와 같은 고형물의 생성 및 집적은 유동안정성 확보(flow assurance) 문제를 발생시켜 안정적인 석유 생산을 방해할 수 있으며, 현장에서는 이를 해결하는데 많은 시간 소모와 경제적 손실이 발생할 수 있다. 왁스집적 문제는 왁스가 생성되기 시작하는 온도인 왁스생성온도 이하의 조건에서만 발생하므로 왁스집적 문제를 예측하고 제어하기 위해서는 오일의 왁스생성온도를 사전에 필수적으로 파악해야한다. 컨덴세이트와 같은 투명 오일의 왁스생성온도는 광학적 기술인 표준측정법이 적용되는 반면 대부분의 현장에서 생산되는 불투명 오일에는 적용이 어려운 한계점이 있다. 이 연구에서는 3가지의 투명 오일시료에 열유량 변화 분석, 점도 변화 분석, 밀도 변화 분석 기법을 적용하여 파악한 왁스생성온도와 표준기법으로 측정한 값과 비교하여 밀도 변화 분석 기법이 가장 신뢰도가 높은 것을 확인하였고 이 기법을 2종류의 불투명 오일시료에 적용하여 왁스생성온도를 결정하였다.

학령중기 남아의 상지동작에 따른 상반신 체표변화 연구 (A Study on the Variation of the Upper Body Surface according to Arm-movements for Middle Elementary Schoolboys)

  • 김미영;여혜린;권영숙
    • 한국의류산업학회지
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    • 제4권2호
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    • pp.137-144
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    • 2002
  • This study was to provide the fundamental data for a scientific and rational clothing construction by investigating the variation of the upper body surface with the use of the method of Surgical tape. The subject were 3 middle elementary schoolboys classified standard somatotype, and arm-movements were consisted of 6 types. The statistical analyses used in this study were mean, standard deviation and the ANOVA and LSD procedure. Shoulder point was moved to be the inside or upside and the shape of the armhole-line was differently changed as the arm-movement become larger. By moving to upside of the anterior armpit point, posterior armpit point and armpit point, the increase of the side seam length and the ascent of the line of width between armpits were distinct. And by arm-movements, in the items of horizontal, front neck base girth, back upper bust girth, back bust girth and back waist girth were increased and the other standard lines were apt to be decreased. In the items of vertical, all standard lines of front side and side seam length showed increased, back waist length and back length showed decreased. The variation of armhole was indefinite. In the rate of the variation, the shoulder length showed the maximum rate of contraction by 41.3%, decreasing 3.7 cm in $180^{\circ}$ degrees, and the side seam length showed the maximum rate of expansion by 60.6%, increasing 8.97 cm in the same degrees.