• Title/Summary/Keyword: Process

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Bootstrap $C_{pp}$ Multiple Process Performance Analysis Chart (붓스트랩 $C_{pp}$ 다공정 수행분석차트)

  • Jang, Dae-Heung
    • Journal of Korean Society for Quality Management
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    • v.38 no.2
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    • pp.171-179
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    • 2010
  • Pearn et al.(2002) supposed the $C_{pp}$ multiple process performance analysis chart. This chart displays multiple processes with the process variation and process departure on one single chart. But, this chart can not display the distribution of the process variation and process departure and is inappropriate for processes with non-normal distributions. With bootstrapping method, we can display the distribution of the process variation and process departure on the $C_{pp}$ multiple process performance analysis chart.

Generation of Alternative Process Plan by Net Model (네트 모델을 이용한 대체 공정 계획 생성)

  • 박지형;박면웅;강민형
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.743-747
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    • 1994
  • A process planning system that generates alternative process plans offers multiple process plans for a part, thereby provides the flexibility to cope with the changes in shop floor status. In this paper, we introduce the concept of process net as a model for the generation of alternative process plans. We also show the usefulness of process net model by implementing the developed system to generate alternative process plans for rotational parts.

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Prospects of Activated Sludge Process in Japan - Its Past, Present, and Future -

  • Fujita, Masanori
    • Journal of Wetlands Research
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    • v.9 no.1
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    • pp.61-67
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    • 2007
  • Our life totally depends on activated sludgeprocess for treatment of wastewater: sewage and industrial wastewater. Activated sludge process was the epoch-making technology in Environmental field. One century has been almost passed since the process was developed in England, and the process is still on the development of improvement. Here, history of activated sludge process, its mechanismsof treating the wastewater, expectations that we had on the process in the past, and future image and possibility on the process were presented. By reviewing the events related to the process, we can foresee potentials for new possibility of activated sludge process.

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A Study on Process Safety Incident Precursors to Prevent Major Process Safety Incidents in the Yeosu Chemical Complex

  • Baek, Seung-Hyun;Kwon, Hyuck-Myun;Byun, Hun-Soo
    • Korean Chemical Engineering Research
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    • v.56 no.2
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    • pp.212-221
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    • 2018
  • Process safety incidents and loss events can be prevented if we identify and adequately take measures on process safety incident precursors in a timely manner. If we look into and take action against the process safety hazard factors causing the incident in the refinery and petrochemical plant, major process safety incidents can be prevented through eliminating or decreasing hazardous factors. We conducted a survey for the major process safety incident precursor to look specifically into the potential process safety hazardous factors of refineries and petrochemical plants in the Yeosu chemical complex. A self-assessment checklist, which was published by Center for Chemical Process Safety "Recognizing catastrophic incident warning signs in the process industry" on major incidents warning sign, was used for the survey. Through this survey, the major process safety incident leading indicators in the process industry were found by process safety management elements, and each site and/or facility can use these leading indicators for activities for process safety incident prevention. In addition, we proposed action items required to eliminate the root cause of those process safety incident leading indicators.

A Multivariate Process Capability Index using Expected Loss (기대손실을 이용한 다변량 공정능력지수)

  • Chung, Young-Bae
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.28 no.4
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    • pp.116-123
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    • 2005
  • The traditional process capability indices Cp, Cpk, Cpm, $Cpm^+$ have been used to characterize process performance on the basis of univariate quality characteristics. Cp, Cpk consider the process variation, Cpm considers both the process variation and the process deviation from target and Cpm+ considers economic loss for the process deviation from target. In manufacturing industry, there is growing interest in quantitative measures of process variation under multivariate duality characteristics. The multivariate process capability index incorporates both the process variation and the process deviation from target or considers expected loss caused by the process deviation from target. This paper proposes multivariate capability index based on the expected loss derived from multivariate normal distribution.

Analysis of Difference Between the Process Capability Indices and the Process Incapability Indices. (공정능력지수와 비공정능력지수의 차이분석)

  • 양정문;이보근;김정자
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.21 no.45
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    • pp.347-356
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    • 1998
  • For assessing the capability of a process, the quantification of process location and variation is central to understanding the quality of units produced from the manufacturing process. Conventional process capability indices is insufficient to drive out the information for process condition, furthermore it is very difficult to evaluate the process capability accurately when the target value is not consistent with the center of specification, and/or the shape of distribution is changed, but the process incapability indices is enable to provide more detailed information to evaluate the process capability by dividing information about the process mean and variance. In this paper, we have a brief review and comparison about these indices, provide an understanding of the relationships between the process capability indices and the incapability indices. And we explore the strengths and weakness of these indices as they apply to normally distributed process, and to examine the effect that non-normality has on these indices.

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Identification Process Variables and Process Improvement Using Data Mining (데이터마이닝을 이용한 공정변수 확인 및 공정개선)

  • Jeong, Young-Soo;Gang, Chang-Uk;Byeon, Seong-Kyu
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.28 no.3
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    • pp.166-171
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    • 2005
  • With development of the database, there are too many data on process variables and the manufacturing process for the traditional statistical process control methods to identify the process variables related with assignable causes. Data mining is useful in this situation and provides variety of approaches for improving the process. In this paper, we applied control charts to monitor the process and if assignable causes are detected, then we applied the SVM technique and the sequence pattern analysis to find out the process variables suspected. These techniques made possible to predict the behavior of process variables. We illustrated our proposed methods with real manufacturing process data.

ISO12207 Tailored Object-Oriented Process for UML Based Object-Oriented Development (UML 기반 객체 지향 개발을 위해 ISO 12207을 조정한 객체지향 프로세스)

  • Lee, Sang-Jun;Kim, Byeong-Gi
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.10
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    • pp.2680-2692
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    • 1999
  • Software quality is classified by quality of process and product. In experience of Quality Management, it is known that quality level of product as it depends on goodness and badness of process and organization. As a result, improvement of software process has been important subject. According as this trends, ISO 12207 is publicated as standard of software life cycle process by ISO. For UML based object oriented development process, it is necessary that we should research detailed definition of activity and task of ISO 12207 process which is added, deleted or tailored in according to organization and project characteristics. In this thesis, by according with ISO 12207 software life cycle process, UML based object oriented development process is proposed. This process is composed of 7 steps and 19 activities including development phase, activity and product to improve quality of reliability. Usefulness of object oriented process for improvement of software quality is proved at three ways, which are comparative analysis of process characteristics, SPICE process evaluation and SPICE rick analysis.

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A Combined Process Control Procedure by Monitoring and Repeated Adjustment

  • Park, Changsoon
    • Communications for Statistical Applications and Methods
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    • v.7 no.3
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    • pp.773-788
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    • 2000
  • Statistical process control (SPC) and engineering process control (EPC) are based on different strategies for processes quality improvement. SPC reduces process variability by detecting and eliminating special causes of process variation. while EPC reduces process variability by adjusting compensatory variables to keep the quality variable close to target. Recently there has been needs for a process control proceduce which combines the tow strategies. This paper considers a combined scheme which simultaneously applies SPC and EPC techniques to reduce the variation of a process. The process model under consideration is an integrated moving average(IMA) process with a step shift. The EPC part of the scheme adjusts the process back to target at every fixed monitoring intervals, which is referred to a repeated adjustment scheme. The SPC part of the scheme uses an exponentially weighted moving average(EWMA) of observed deviation from target to detect special causes. A Markov chain model is developed to relate the scheme's expected cost per unit time to the design parameters of he combined control scheme. The expected cost per unit time is composed of off-target cost, adjustment cost, monitoring cost, and false alarm cost.

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A Study on the Elevation of Software Process Level and Performance through Software Process Improvement (소프트웨어 프로세스 개선을 통한 프로세스 수준과 성과 향상 방안)

  • Moon Song-Chul;Kim Hyun-Soo
    • The KIPS Transactions:PartD
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    • v.13D no.1 s.104
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    • pp.75-86
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    • 2006
  • This paper studied the improvement of software process of the software firms. Software process infrastructure level of software process is very important. This study provided that software process infrastructure have an significant influence on the process level, process infrastructure management level, and software process performance. The result showed that software process high level is elevated through management activity of organization infrastructure and technical infrastructure. And organization performance is elevated through fit between process level and quality culture of software process. Problem factors of software process infrastructure improvement is lack of process improvement mind, leadership and investment. Therefore software firms must construct process improvement through supporting of process quality mind and investment with process infrastructure improvement.