• Title/Summary/Keyword: statistical quality control

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Exploiting a Statistical Threshold for Efficiently Identifying Correlated Pairs

  • Kim, Myoung-Ju;Park, Hee-Chang
    • Journal of the Korean Data and Information Science Society
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    • v.19 no.2
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    • pp.551-558
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    • 2008
  • Association rule mining searches for interesting relationships among items in a given database. Association rules are frequently used by retail stores to assist in marketing, advertising, floor placement, and inventory control. There are three primary quality measures for association rule, support and confidence and lift. If there is many item in the association rule, much time is required. Xiong(2004) studies new method which is to compute the support of upper. They used support of upper to the $^{\theta}$. But $^{\theta}$ is subjective. In this paper, we present statistical objective criterion for efficiently identifying correlated pairs.

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Simultaneous Tests with Combining Functions under Normality

  • Park, Hyo-Il
    • Communications for Statistical Applications and Methods
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    • v.22 no.6
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    • pp.639-646
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    • 2015
  • We propose simultaneous tests for mean and variance under the normality assumption. After formulating the null hypothesis and its alternative, we construct test statistics based on the individual p-values for the partial tests with combining functions and derive the null distributions for the combining functions. We then illustrate our procedure with industrial data and compare the efficiency among the combining functions with individual partial ones by obtaining empirical powers through a simulation study. A discussion then follows on the intersection-union test with a combining function and simultaneous confidence region as a simultaneous inference; in addition, we discuss weighted functions and applications to the statistical quality control. Finally we comment on nonparametric simultaneous tests.

Exploiting a statistical threshold for efficiently identifying correlated pairs

  • Kim, Myoung-Ju;Park, Hee-Chang
    • 한국데이터정보과학회:학술대회논문집
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    • 2006.11a
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    • pp.197-203
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    • 2006
  • Association rule mining searches for interesting relationships among Items in a given database. Association rules are frequently used by retail stores to assist in marketing, advertising, floor placement, and inventory control. There are three primary quality measures for association rule support and confidence and lift. If there is many item in the association rule, much time is required. Xiong(2004) studies new method which is to compute the support of upper. They used support of upper to the $\theta$. But $\theta$ is subjective. In this paper, we present statistical objective criterion for efficiently identifying correlated pairs.

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A Study for Statistical Criterion in Negative Association Rules Using Boolean Analyzer

  • Shin, Sang-Jin;Lee, Keun-Woo
    • 한국데이터정보과학회:학술대회논문집
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    • 2006.11a
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    • pp.145-151
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    • 2006
  • Association rule mining searches for interesting relationships among items in a given database. Association rules are frequently used by retail stores to assist in marketing, advertising, floor placement, and inventory control. There are three primary quality measures for association rule support and confidence and lift. Association rule is an interesting rule among purchased items in transaction, but the negative association rule is an interesting rule that includes items which are not purchased. Boolean Analyzer is the method to produce the negative association rule using PIM. But PIM is subjective. In this paper, we present statistical objective criterion in negative association rules using Boolean Analyzer.

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Design of ALT Control Chart for Small Process Variation (미세변동공정관리를 위한 가속수명시험관리도 설계)

  • Kim, Jong-Gurl;Um, Sang-Joon
    • Journal of the Korea Safety Management & Science
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    • v.14 no.3
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    • pp.167-174
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    • 2012
  • In the manufacturing process the most widely used $\bar{X}$ chart has been applied to control the process mean. Also, Accelerated Life Test(ALT) is commonly used for efficient assurance of product life in development phases, which can be applied in production reliability acceptance test. When life data has lognormal distribution, through censored ALT design so that censored ALT data has asymptotic normal distribution, $ALT\bar{X}$ control chart integrating $\bar{X}$ chart and ALT procedure could be applied to control the mean of process in the manufacturing process. In the situation that process variation is controlled, $Z_p$ control chart is an effective method for the very small fraction nonconforming of quality characteristic. A simultaneous control scheme with $ALT\bar{X}$ control chart and $Z_p$ control chart is designed for the very small fraction nonconforming of product lifetime.

Empirical Analysis for Evaluation Index of Quality Competitiveness Excellent Companies (품질경쟁력 우수기업의 평가지표에 대한 실증적 분석)

  • Park, Dong Joon
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.39 no.1
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    • pp.37-46
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    • 2016
  • Quality has been a key issue to manufacturers. Many distinguished scholars have defined quality with profound insight. Korean firms struggle to make better products to fulfil requirements and satisfy customers. Korean industries have implemented quality management from Japan in early 70s. Statistical quality control, QCC (Quality Control Circle), and total quality management have also been introduced in succession. Chief executive officers, managers, and field employees have been aware of the importance of quality since then. This quality movement force workers to improve quality. They have to maintain the quality of products and compete with foreign products. Korean industries were able to compete with foreign industries in price. However, Korean firms now have to compete in quality as well as price. ISO (International Organization for Standardization) was established and industries around world have started to implement standardized systems depending on their need. ISO 9000 has continuously been revised and firms around world started to register a ISO 9000 certificate. Today's quality competitiveness gets more deeply involved. KSA (Korean Standard Association) have launched QCAS (Quality Competitiveness Assessment System) since 1997. Up until now recent status of QCAS have been reported but the characteristics of QCAS results have not been analyzed. In this article we examine the QCAS results of 41 firms in 2014. QCAS consisted of 13 subsections : strategy and management system, organization culture and development of human resource, information management, quality system, customer satisfaction, management achievement, TPM, logistics, product development and technology, PL, QCC, SQC/SPC, and reliability. We performed one way ANOVA to discover the difference among the levels of firm size, business type, and quality hall of fame using the total scores of 13 subsections resulted from QCAS. We also analyzed the scores of 13 individual subsections of QCAS to see if there is any differences based on firm size and business type. We interpret the results and implication of analysis and finally draw a conclusion.

Statistical Quality Control of Herbal Drugstuffs Distributed in Seoul Area - Centering around Ash, Acid-insoluble Ash, Loss on Drying and Hazardous Heavy Metals - (서울지역 유통한약재의 통계적 품질관리 - 회분, 산불용성회분, 건조감량, 유해중금속을 중심으로 -)

  • Kim, Dong-Gyu;Kim, Bog-Soon;Han, Chang-Ho;Kim, Eun-Ju;Choi, Byung-Hyun;Park, Seung-Kook
    • YAKHAK HOEJI
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    • v.53 no.5
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    • pp.274-280
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    • 2009
  • To survey the status of quality control of major ingredients of 'Ssanghwatang (Oriental medicine used for fatigue)', we analyzed 1,024 samples (9 kinds) of medical herbs to determine amounts of ashes, acid-insoluble ashes, loss on drying that are major elements to ensure basic quality of herbal drugstuffs. After ash analysis, Paeoniae Radix (from China) failed to meet the herbal standard criterion. After yielding Z-score(indicating the probability of exceeding its criterion) Zizyphi Fructus, Zingiberis Rhizoma, Paeoniae Radix, Rehmanniae Radix Preparata became objects of intense quality control (=IQC). Analysis on loss on drying shows Cinnamomi Cortex was unsuitable and was put under the IQC. In case of respective heavy metals, Angelicae Gigantis Radix, Cnidii Rhizoma, Cinnamomi Cortex exceeded the maximum permissible range for Cd. The 3 kinds of sub-standards were put to the IQC. Statistic figures showed a significant correlation (t-test, p<0.01) between country-of-origin and sub-quality rates. Compared to domestic one, imported medicinal herbs were less suitable in regard of acid-insoluble ash, loss on drying and Pb/Hg content. Meanwhile, amounts of Acid-insoluble ash showed positive relation with amounts of Pb (r=0.202) and As (r=0.243) among heavy metals leading to an inference that herbs of which root/rhizome is used for medical purposes attribute its high heavy metal content to the fine earth/sand being stuck to its root stalk.

A Study on Improvement of Organizational Culture of the Members of Manufacturing and Service industry Quality Control : Focused on Mediation Effect of Job Satisfaction (제조업과 서비스업 품질관리 종사원들의 조직문화 개선에 관한 연구 : 직무만족의 매개변수를 중심으로)

  • Lee, Chul Woo;Shin, Yong Ho;Shang, Meng;Ryu, Young Shin
    • Journal of Korean Society for Quality Management
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    • v.48 no.1
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    • pp.29-50
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    • 2020
  • Purpose: Targeting the members of manufacturing and Service industry Quality Control team this study is going is to carry out research about whether the outcome of OCB(Organizational Citizenship Behaviors) and organization can be brought about by organizational culture that is suitable for them. this study tries to identify the direct・indirect causal relationship between these variables and OCB by selecting organizational culture as a leading variable and job satisfaction as a parameter. Methods: SPSS 22.0 was used for data analysis and AMOS 18.0 statistical program for structural equation model analysis. For the descriptive statistics this study verified reliability analysis, feasibility analysis, structural equation model analysis, research hypothesis, and mediating effects. Results: As a result of path analysis estimating the regression coefficients for the linear structure analysis of the correlations between variables for the hypothesis verification, the rational culture among the organizational culture types of the manufacturing Quality Control team showed a positive (+) effect on the job satisfaction, and hierarchical culture has negative(-) effect on job satisfaction. Conclusion: This study suggested that the composition and friendly behavior of desirable organizational culture has a very close relationship in connection between job satisfaction and OCB by examining the causal relationship between OCB for improvement activities for organizational culture by establishing the organizational culture and job satisfaction of the manufacturing Quality Control team.

Web Based rSPC System Supporting XML Protocol (XML 프로토콜을 지원하는 웹기반 rSPC 시스템)

  • Oh, Kyoung-Je;Han, Sang-Yong
    • The KIPS Transactions:PartA
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    • v.10A no.1
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    • pp.69-74
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    • 2003
  • Accurate process control in the manufacturing industry is essential to survive in the competitive market. Statistical process control (SPC) system has been widely used to satisfy the ever-increasing quality control requirements. However, most commercial products in the market are not flexible, semi-automatic, and difficult to interface with other tools. In this paper, we propose an advanced rSPC (Real-Time SPC) system which is based on the web and supports XML protocol. We also provide a powerful graphic facility and an efficient file system to handle the data in real time. Even though the idea can be applied to any manufacturing system, our system is optimized to the semi-conductor industry and TFT/LCD industry. The system is implemented in C++ and COM/DCOM, and shows a good result.

Applicability of Statistical Evaluation to Power Quality Analysis (통계적 방법을 이용한 전력품질 관리방안)

  • Cho, Soo-Hwan;Jang, Gil-Soo;Kwon, Sae-Hyuk;Park, Sang-Ho;Jeon, Young-Soo;Kwak, No-Hong
    • Proceedings of the KIEE Conference
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    • 2006.07a
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    • pp.22-24
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    • 2006
  • The installations of power quality monitoring system have increased drastically over the past several decades. These systems have been effectively used to monitor, analyze and diagnose the conditions of power system, and furthermore can be used to improve the present asset maintenance policy, scheduled (time-based) method, into the advanced, cost-effective and labor-effective maintenance methods, such as condition-based maintenance, predictive maintenance and reliability centered maintenance. As an approach to this, this paper introduces the statistical methods, three kinds of control charts (Shewhart chart, CUSUM chart and EWMA chart), and discusses the applicability of these methods to recognize the changing trends of power quality indices and to estimate the system's condition, using Matlab.

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