• Title/Summary/Keyword: Statistical quality control

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한국 노인의 구강건강수준에 따른 영양섭취 상태 - 2009년 국민건강영양조사 자료에 근거하여 - (Nutritional status of Korean elderly by oral health level - based on 2009 national health and nutrition survey data)

  • 김철신;신보미;배수명
    • 한국치위생학회지
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    • 제11권6호
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    • pp.833-841
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    • 2011
  • Objectives : The purpose of this study was investigation of quality and quantity of nutritional intake related oral health status among Korean elders. Methods : The nutrient intake and the dietary quality was evaluated on the basis of the Dietary Reference Intakes For Koreans(KDRIs). Chi-square test for Complex Samples was used to determine the relationship between oral health and inadequate nutrient intake in Korean elders. The complex samples general linear model was used to test difference of average value difference of nutrient intake percentage compared to dietary reference intake(DRI), energy intake rate from three major nutrients, average mean adequacy ratio(MAR) and index of nutritional quality(INQ) related oral health status. Age, sex and total energy intake was compensated for this analysis. PASW 18 was used for statistical analysis. Results : We could found the difference of the nutrient intake and the dietary quality related oral health status among Korean elders. Especially, Nutrient intake percentage and component ratio of protein among energy intake rate from three major nutrient was lower as oral health status became worse. The percentage of subjects with nutritional intakes under showed highest level in worst oral health status. As oral health status became worse, average mean adequacy ratio(MAR) was lower and the number of nutrient of which index of nutritional quality(INQ) was under 1 was more. Conclusions : From the result above, this study clearly shows the level of oral health affecting the inequalities of eating and the food for the people. And the various propose of oral health policies is needed for vulnerable groups who needs solution to solve the problem of inequality of food distribution where intensive distribution of nutrition problem occurred. Sufficient, safe, and a variety of healthy food intake is a fundamental right of our people. And also, to apply this policy in reality, institutional arrangements and organizations, and specific performing system will be needed.

통계분석을 이용한 낙동강유역의 수질변화 특성 조사 (Evaluation of Water Quality Characteristics in the Nakdong River using Statistical Analysis)

  • 최길용;임태효;이재운;천세억
    • 한국수자원학회논문집
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    • 제45권11호
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    • pp.1157-1168
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    • 2012
  • 본 연구에서는 시간에 따른 수질 변화를 파악하고 원인에 따른 경향을 분석함으로써 적절한 관리대책을 수립하는 것이 필요하다고 생각되어 이 같은 연구를 하게 되었다. 현재 수질오염이 심각한 낙동강 수계를 대상으로 2006~2010년까지 수질변화를 분석하였다. 수계의 803개, 국가하천 13개소, 지방1급 하천은 10개소, 하천에 합류하는 하천은 31개 지점에서 측정한 수은, BOD(Biological Oxygen Demand), TN(Total Nitrogen)과 TP(Total Phosphorus) 등의 월평균 자료결과를 바탕으로 하여 통계적 분석(상관분석, 회귀분석, 분산분석, 시계열분석)을 통한 낙동강 유역의 인근 지역의 계절별로 수질항목을 확인하였으며, 평가지표에 따른 변화를 측정하고자 하였다. 유역의 지질 및 지형의 영향이 주로 작용하는데 지역의 기후조건, 식생, 지형, 토양, 비포화대 매질의 영향을 받기 때문에 여러가지의 변수를 가지고 유출했으며, 이는 방류량의 결정문제, 호소의 부영양화 문제 등이 제기될 수 있겠으며, 좋은 개선방안을 만들어보려고 한다. 따라서 낙동강의 강우기 유량을 증대하는 대책이 병행되는 것이 바람직하며, 물 관리 대책에는 하천유지용수 확보를 구성을 해야하며, 수로 건설사업 완료를 지속적인 관찰이 필요하다. 그러나 지류에는 물이 흐르지 않는 시기가 발생하는 이유는 자연 상태에서 흘러야 하는 하천수 및 공업용수와 농업용수로 취수했기 때문이다. 따라서 이모든 것을 관찰 및 구성을 하기 위해서는 지속적인 연구가 필요로 하며, 다음과 같은 연구의 목적을 두고 연구조사 하였다.

선형 탐촉자에서 관심 시각 영역 변화에 따른 화질 분석 (Image Quality Analysis According to the of a Linear Transducer)

  • 박지나;한재복;곽종길;송종남
    • 한국방사선학회논문지
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    • 제16권7호
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    • pp.975-984
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    • 2022
  • 선형 탐촉자는 탐촉자의 길이만큼의 관심 영역을 갖기 때문에 장비에 탑재된 virtual convex 기능을 사용하여 관심 영역을 확장 시킬 수 있다. 하지만 관심 시각 영역의 변화에 따라 초음파 음속 방향의 변화로 인해 화질에 영향을 미칠 것으로 생각되어 이를 객관적으로 확인하고자 하였다. 본 연구를 위해 초음파 정도 관리용 팬텀의 영상 평가와 SNR·CNR을 측정하였다. 그 결과 팬텀 영상 평가에서는 두 영상 모두 기능적 분해능, 회색조 및 동적 범위에서 모두 구조물 식별이 가능했다. 하지만 구조물의 크기와 형태 재현성에는 Standard 영상이 우수한 것을 확인할 수 있었다. SNR·CNR 평가결과, 특정 위치의 구조물을 제외하고는 대부분이 Trapezoidal 영상의 SNR·CNR이 낮았다. 또한, 통계 분석 그래프를 통해 낭성 구조물의 크기가 작아질수록 깊이별 SNR과 CNR이 감소하는 것을 추가로 확인할 수 있었다. 본 연구를 통해 기능사용이 넓은 관심 시각 영역을 제공하는 장점이 있으나 화질에 영향을 준다는 것을 확인할 수 있었으며 Virtual Convex 기능사용 시 검사자는 이를 적절한 상황에 사용하고 질 높은 영상 획득과 장비의 이해도와 숙련도 향상을 위해 다양한 연구를 해야 할 것으로 판단된다.

비정규분포공정에서 매디안특수관리도의 모형설계와 적용연구 (Median Control Chart for Nonnormally Distributed Processes)

  • 신용백
    • 기술사
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    • 제20권3호
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    • pp.15-25
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    • 1987
  • Statistical control charts are useful tools to monitor and control the manufacturing processes and are widely used in most Korean industries. Many Korean companies, however, do not always obtain desired results from the traditional control charts by Shewhart such as the X-chart, X-chart, X-chart, etc. This is partly because the quality charterstics of the process are not distributed normally but are skewed due to the intermittent production, small lot size, etc. In Shewhart X-chart, which is the most widely used one in Korea, such skewed distributions make the plots to be inclined below or above the central line or outside the control limits although no assignable causes can be found. To overcome such shortcomings in nonnormally distributed processes, a distribution-free type of confidence interval can be used, which should be based on order statistics. This thesis is concerned with the design of control chart based on a sample median which is easy to use in practical situation and therefore properties for nonnormal distributions may be easily analyzed. Control limits and central lines are given for tile more famous nonnormal distributions, such as Gamma, Beta, Lognormal, Weibull, Pareto, Truncated-normal distributions. Robustness of the proposed median control chart is compared with that of the X-chart, the former tends to be superior to the latter as the probability distribution of the process becomes more skewed. The average run length to detect the assignable cause is also compared when the process has a Normal or a Gamma distribution for which the properties of X are easy to verify, the proposed chart is slightly worse than the X-chart for the normally distributed product but much better for Gamma-distributed products. Average Run Lengths of the other distributions are also computed. To use the proposed control chart, the probability distribution of the process should be known or estimated. If it is not possible, the results of comparison of the robustness force us to use the proposed median control chart based on a normal distribution. To estimate the distribution of the process, Sturge's formula is used to graph the histogram and the method of probability plotting, $X^2$-goodness of fit test and Kolmogorov-Smirnov test, are discussed with real case examples. A comparison of the propose4 median chart and the X chart was also performed with these examples and the median chart turned out to be superior to the X-chart.

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비정규분포공정에서 메디안특수관리도 통용모형설정에 관한 실증적 연구(요약) (Median Control Chart for Nonnormally Distributed Processes)

  • 신용백
    • 산업경영시스템학회지
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    • 제10권16호
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    • pp.101-106
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    • 1987
  • Statistical control charts are useful tools to monitor and control the manufacturing processes and are widely used in most Korean industries. Many Korean companies, however, do not always obtain desired results from the traditional control charts by Shewhart such as the $\bar{X}$-chart, $\bar{X}$-chart, $\bar{X}$-chart, etc. This is partly because the quality charterstics of the process are not distributed normally but are skewed due to the intermittent production, small lot size, etc. In Shewhart $\bar{X}$-chart. which is the most widely used one in Kora, such skewed distributions make the plots to be inclined below or above the central line or outside the control limits although no assignable causes can be found. To overcome such shortcomings in nonnormally distributed processes, a distribution-free type of confidence interval can be used, which should be based on order statistics. This thesis is concerned with the design of control chart based on a sample median which is easy to use in practical situation and therefore properties for nonnormal distributions may be easily analyzed. Control limits and central lines are given for the more famous nonnormal distributions, such as Gamma, Beta, Lognormal, Weibull, Pareto, Truncated-normal distributions. Robustness of the proposed median control chart is compared with that of the $\bar{X}$-chart; the former tends to be superior to the latter as the probability distribution of the process becomes more skewed. The average run length to detect the assignable cause is also compared when the process has a Normal or a Gamma distribution for which the properties of X are easy to verify, the proposed chart is slightly worse than the $\bar{X}$-chart for the normally distributed product but much better for Gamma-distributed products. Average Run Lengths of the other distributions are also computed. To use the proposed control chart, the probability distribution of the process should be known or estimated. If it is not possible, the results of comparison of the robustness force us to use the proposed median control chart based oh a normal distribution. To estimate the distribution of the process, Sturge's formula is used to graph the histogram and the method of probability plotting, $\chi$$^2$-goodness of fit test and Kolmogorov-Smirnov test, are discussed with real case examples. A comparison of the proposed median chart and the $\bar{X}$ chart was also performed with these examples and the median chart turned out to be superior to the $\bar{X}$-chart.

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A convergence analysis of Block MADF algorithm for adaptive noise reduction

  • Min, Seung-gi;Young Huh;Yoon, Dal-hwan
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2002년도 ITC-CSCC -1
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    • pp.377-380
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    • 2002
  • When it calculates the optimum price of filter coefficient, the many operation quantity is necessary. Is like that the real-time control is difficult and the hardware embodiment expense is big. The case which does not know advance information of input signal or the case where the statistical nature changes with change of surroundings environment is necessary the adaptive filter. Every hour to change a coefficient automatically and system in order to reach to the condition of optimum oneself, the fact that is the adaptive filter. When it does not the quality of input signal or it does not know the environment of surroundings every hour changing, it does not emit not to be, in order to collect, the fact that is the adaptive filter. The case of the Acoustic Echo Canceler does thousands filter coefficients in necessity. It reduces a many calculation quantity to respect, it uses the IIR filter from hour territory. Also it uses the block adaptive filter which has a block input signal and a block output signal. The former there is a weak point where the stability discrimination is always demanded. Consequently, The block adaptive filter is researched plentifully. This dissertation planned the block MADF adaptive filter used to MADf algorithm.

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Monitor Backcover의 사이클 타임 단축에 관한 연구 (A Study on The Reduction of Cycle Time in Injection Molding Process of The Monitor Backcover)

  • 윤경환;김주권
    • 소성∙가공
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    • 제14권4호
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    • pp.368-374
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    • 2005
  • In the present study we used a diagrammatic analysis of 6 sigma quality control and Taguchi method for injection molding of monitor back-cover, evaluated the influence on the cycle time with part design, mold design, molding process and standardization activity involving design and molding, adopted analysis of sensitivity and effective factors of the part design and molding process conditions for productivity, identified main design molding factors. The contributing factors for the final cycle time could be enumerated as follows; the thickness of hot spot, main nominal part thickness, coolant inlet temperature, melt temperature and cooling line layout, etc.. As a first step, all the critical factors of design process applied to the current monitor housing were investigated through 6 sigma process. Thereafter, the optimal and better critical factors found in the first step were applied to new product design to prove that our process was correct. The Moldflow was used for injection molding simulation, and Minitab software for the statistical analysis, respectively. Finally, the productivity of new design was increased about 33 percents for our specific case.

INAA.ICP.AAS를 이용한 대기먼지 $(PM_{10})$의 다원소분석 (Multielement Analysis in Airborne Particulate Matter $(PM_{10})$ by INAA, ICP and AAS)

  • 정용삼;문종화;정영주;박광원;이길용;윤윤열;심상권;조경행;한명섭
    • 한국대기환경학회지
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    • 제15권4호
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    • pp.495-503
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    • 1999
  • Airborne particulate matter $(PM_{10})$ collected using high volume air sampler and silica fiber filter were analyzed by Instrumental Neutron Activation Analysis(INAA), Inductively Coupled Plasma Atomic Emission Spectrometry(ICP-AES) and Atomic Absorption Spectrometry(AAS), and the results were compared with each other. 30~40 trace elements in environmental standard reference materials(NIST SRM 1648 and NIES CRM No.8) were analyzed for the analytical quality control. The relative error for two-third of elements detected was less than 10%, and the standard deviation was less than 15%. During the sampling period for 24 hours, the mass concentration of total suspended particulate was 36.1$\mu\textrm{g}$/㎥ and the value is lower than the critical level in Korea. In the results of NAA, the elements of Al, As, Ba, Fe, La, Mg, Na, Sb, Zn were well agreed with those of other methods. In statistical estimation between different methods, the deviation of Al, Ba, Cr, Fe was less than 10% and quite reliable.

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항공기체구조의 정밀조립 및 동시설계 기술 (Accurate Assembly and Concurrent Design of Airframe Structures)

  • 박문식
    • 대한기계학회논문집A
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    • 제24권4호
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    • pp.811-823
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    • 2000
  • In design and manufacturing airframe structures which are composed of a lot of sub-assemblies and large complex profile shapes it is difficult to reduce so called hardware variations. Accordingly cost increasing factors for manufacturing airframe parts are much more than other machine parts because of the variability of fabricated details and assemlies. To improve cost and quality, accurate assembly methods and DPD techniques are proposed in this paper which are based upon using CAD/CAM techniques, the concept of KC's and the coordinated datum and index throughout the design, tooling, manufacturing and inspection. The proposed methods are applied to produce fuselage frame assemblies and related engineering aspects are described regarding the design of parts and tools in the context of concurrent digital definition. First articles and consequent mass production of frame assemblies shows a great improvement of the process capability ratio from 0.7 by the past processes to 1.0 by the proposed methods in addition to the cost reduction due to the less number of tools, reduced total assembly times and the space compaction needed by massive inventory. The need to achieve better Cpk, however, and future studies to be investigated will be addressed briefly.

열처리에 의한 청변균 변색 소나무 판재의 재색 변화 (Effect of Heat Treatment on the Color Change of Blue-Stained Pinus densiflora Boards)

  • 이원희;임호묵;강호양
    • 한국가구학회지
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    • 제25권4호
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    • pp.319-324
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    • 2014
  • Red pine is a popular species for making a cutting board in Korea, but easily sap stained. Heat treatment could improve its quality by darkening and equalizing the color of sap stained wood. The color change of sap stained red pine boards was investigated by heat treatment at $190^{\circ}C$. It was observed that the color of heat treated boards got darker and it made the color of sap stain vanished. A colorimeter was used to measure color indexes. It was revealed that the values of the lightness ($L^*$) and the yellowness ($b^*$) decreased as heat treatment repeated while the values of the redness ($a^*$) increased. The average of the color difference (${\Delta}E^*$) between the control and 1st heat treated boards was 16.1, which could be expressed as 'Extremely different' while that between the 1st and 2nd heat treated boards was 8.3, which could be expressed as 'Considerably different'. The fact that heat treatment equalized the color of boards was confirmed by a statistical analysis.

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