• Title/Summary/Keyword: Quality control

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Response Surface Approach to Integrated Optimization Modeling for Parameter and Tolerance Design (반응표면분석법을 이용한 모수 및 공차설계 통합모형)

  • Young Jin Kim
    • Journal of Korean Society for Quality Management
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    • v.30 no.4
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    • pp.58-67
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    • 2002
  • Since the inception of off-line quality control, it has drawn a particular attention from research community and it has been implemented in a wide variety of industries mainly due to its extensive applicability to numerous real situations. Emphasizing design issues rather than control issues related to manufacturing processes, off-line quality control has been recognized as a cost-effective approach to quality improvement. It mainly consists of three design stages: system design, parameter design, and tolerance design which are implemented in a sequential manner. Utilizing experimental designs and optimization techniques, off-line quality control is aimed at achieving product performance insensitive to external noises by reducing process variability. In spite of its conceptual soundness and practical significance, however, off-line quality control has also been criticized to a great extent due to its heuristic nature of investigation. In addition, it has also been pointed out that the process optimization procedures are inefficient. To enhance the current practice of off-line quality control, this study proposes an integrated optimization model by utilizing a well-established statistical tool, so called response surface methodology (RSM), and a tolerance - cost relationship.

Research of the Relationships between Self-control, Thinking Quality and Mathematical Academic Achievement for Senior School Students

  • Yu, Wenhua;Yu, Ping
    • Research in Mathematical Education
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    • v.14 no.1
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    • pp.79-98
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    • 2010
  • To analyze the relationships between self-control, thinking quality and mathematical academic achievement, 197 senior school students were asked to complete questionnaires called "self-control ability on mathematics for middle school students" and "thinking quality for senior school students." The results were as follows: (1) There was strongly positive relevance between self-control ability, thinking quality and mathematical academic achievement. (2) A model was presented in which self-control ability had a direct impact on mathematical academic achievement, meanwhile had indirectly influenced mathematical academic achievement by thinking quality which acted as the intermediate variable. Thinking quality had a direct impact on mathematical academic achievement, too. (3) There's no significant difference between the two groups of boys and girls on the structural weights.

Joint Quality Control of VBR MPEG Video Programs (VBR MPEG 비디오 프로그램들의 결합 화질 제어)

  • 홍성훈;김성대
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.591-596
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    • 1999
  • In this paper, we present a joint quality control system to be able to accurately control the relative picture quality among the video programs in terms of PSNR. The joint quality control system allows variable bit rate (VBR) for each video program to maintain the pre-determined relative picture quality among the aggregated video programs while keeping a constant sum of the bit rates for all programs to be transmitted over a single constant bit rate (CBR) channel. This is achieved by simultaneous controlling the video encoders to generate VBR video streams at the central controller. Furthermore we also suggest buffer regulation method based on the analysis of the constraints imposed by sender/receiver buffer sizes and total transmission rate. Through various simulation results, it is found that our quality control systems guarantee that the video buffers do not overflow and underflow and the quality control errors do not exceed 0.1 ㏈.

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The Role of mRNA Quality Control in the Aging of Caenorhabditis elegans

  • Hyunwoo C. Kwon;Yunkyu Bae;Seung-Jae V. Lee
    • Molecules and Cells
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    • v.46 no.11
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    • pp.664-671
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    • 2023
  • The proper maintenance of mRNA quality that is regulated by diverse surveillance pathways is essential for cellular homeostasis and is highly conserved among eukaryotes. Here, we review findings regarding the role of mRNA quality control in the aging and longevity of Caenorhabditis elegans, an outstanding model for aging research. We discuss the recently discovered functions of the proper regulation of nonsense-mediated mRNA decay, ribosome-associated quality control, and mRNA splicing in the aging of C. elegans. We describe how mRNA quality control contributes to longevity conferred by various regimens, including inhibition of insulin/insulin-like growth factor 1 (IGF-1) signaling, dietary restriction, and reduced mechanistic target of rapamycin signaling. This review provides valuable information regarding the relationship between the mRNA quality control and aging in C. elegans, which may lead to insights into healthy longevity in complex organisms, including humans.

A Design of Economic CUSUM Control Chart Incorporating Quality Loss Function (품질손실을 고려한 경제적 CUSUM 관리도)

  • Kim, Jungdae
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.41 no.4
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    • pp.203-212
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    • 2018
  • Quality requirements of manufactured products or parts are given in the form of specification limits on the quality characteristics of individual units. If a product is to meet the customer's fitness for use criteria, it should be produced by a process which is stable or repeatable. In other words, it must be capable of operating with little variability around the target value or nominal value of the product's quality characteristic. In order to maintain and improve product quality, we need to apply statistical process control techniques such as histogram, check sheet, Pareto chart, cause and effect diagram, or control charts. Among those techniques, the most important one is control charting. The cumulative sum (CUSUM) control charts have been used in statistical process control (SPC) in industries for monitoring process shifts and supporting online measurement. The objective of this research is to apply Taguchi's quality loss function concept to cost based CUSUM control chart design. In this study, a modified quality loss function was developed to reflect quality loss situation where general quadratic loss curve is not appropriate. This research also provided a methodology for the design of CUSUM charts using Taguchi quality loss function concept based on the minimum cost per hour criterion. The new model differs from previous models in that the model assumes that quality loss is incurred even in the incontrol period. This model was compared with other cost based CUSUM models by Wu and Goel, According to numerical sensitivity analysis, the proposed model results in longer average run length in in-control period compared to the other two models.

Investigation for the Induction of Quality Inscription System with Herbal Medicine (한약재 품질 표시 제도의 도입을 위한 조사)

  • Lee, Mi-Young;Kim, Ho-Kyoung;Jeon, Won-Kyung;Jung, Gye-Jin;Ju, Young-Seung;Ju, Young-Seung;Ko, Byoung-Seob
    • Korean Journal of Oriental Medicine
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    • v.6 no.1
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    • pp.59-68
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    • 2000
  • The purpose of this study is to encourage the circulation of good quality of oriental medicine and to improve national welfare. Investigation for the induction of quality inscription system was conducted by mail and interview. The data were analyzed by SAS. The major results were as follows: The portion of subjects agree to necessity of quality inscription was 78.5%. In the question of side effect against quality inscription, the rate of negative was 67.7%. The responses answered that the necessity of quality inscription was not economical profit but authority of knowledge and improvement on health(37.8%), established market for herbal medicine(34.7%) and effect of clinical care(23.9%), respectively These results might be useful information for establishing of quality inscription system for herbal medicine.

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A case study on the quality control strengthening in development phase of weapon systems (무기체계 개발단계 품질관리 강화에 관한 사례 연구)

  • Jung, Il Ho;Seo, Sang Won;Jang, Bong Ki
    • Journal of Korean Society for Quality Management
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    • v.45 no.3
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    • pp.349-364
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    • 2017
  • Purpose: The purpose of this study is to analyze quality control strengthening pilot project in development stages of weapon systems which ensures zero-defect. In order to achieve that, we propose collaboration support system between related organizations. Methods: First, we analyze how quality control methods has been developed from reviewing the preliminary study in commercial and defense industry. Then, we suggest improvement plans for quality control in defense industry and propose a pilot study which able to improve the recognized problems. Results: The results of this study ensures the participants in defense industry recognize the importance of quality control and form a consensus by sharing a case study. Finally, we propose the standardized work process by utilizing manual and manpower dispatching. Conclusion: As a result, this study clarifies the scope and role of relevant organizations to achieve the defense quality assurance in the total life cycle(TLC). Also, this paper guides the collaboration system between the relevant organization which differs from the commercial industry currently divided into development-production-quality.

The Relationship Between Internal Control and Accounting Information Quality: Empirical Evidence from Manufacturing Sector in Vietnam

  • NGO, Hoang Thanh;LUU, Duc Huu;TRUONG, Thuy Thi
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.10
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    • pp.353-359
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    • 2021
  • The article analyzes the impact of internal control on the quality of accounting information in Vietnamese paper manufacturing enterprises, providing empirical evidence on factors affecting the quality of accounting information. To analyze the impact of internal control on the quality of accounting information, the researchers used questionnaires to conduct a survey of paper manufacturing companies. Research data is collected through emails and face-to-face interviews with managers, employees working in different positions, managers at all levels, chief accountants, and accountants, of 56 paper manufacturing enterprises in Vietnam. 321 questionnaires were distributed of which only 296 were valid and could be used in this study. Quantitative research was carried out with SPSS 25 software. Research results show that 3 factors have a positive influence on the quality of accounting information including control environment, accounting information system, and internal control procedures in Vietnamese paper manufacturing enterprises. Based on the findings, the author has made recommendations on the control environment, accounting information system, and internal control procedures in order to improve the effectiveness of internal control and the quality of accounting information of paper production enterprises, thereby contributing to improved competitiveness and operational efficiency.

A New Measurement Unit for Quality control in Venture Business (벤처기업을 위한 새로운 품질관리 측정단위의 개발)

  • Ree, Sang-Bok;Park, Roh-Gook
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.6 no.2
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    • pp.13-24
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    • 2011
  • In this Paper, We study on establish for unit of measure. Quality control is means control for customer needs. We surveyed unit of measurement of quality feature of Juran and Taguchi teaching. We suggest new measure of quality feature. New quality measure which is combined with several quality control measures. Which measurement can be used management control of managerial level of company. We expect this new measurements can be applied and well used.

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QFD as a Tool to Improve Quality Control in a Complex Manufacturing Environment

  • Backstrom, Mikael;Wiklund, Hakan
    • International Journal of Quality Innovation
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    • v.5 no.1
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    • pp.10-22
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    • 2004
  • The paper outlines a comprehensive three-step approach to the development of advanced strategies for quality control of a complex machining process. The research framework is a developed concept for Integrated Supervisory Process Control. The promising results obtained demonstrate a non-traditional approach to the deployment of quality and productivity requirements set by the system users, whereby the efficiency and systematization of the development of quality control strategies can be significantly improved.