• 대한안전경영과학회지
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• 제12권4호
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• pp.255-263
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• 2010

The research developes short-run standardized control charts(SSCC) and short-run acceptance control charts(SACC) under the various demand patterns. The demand patterns considered in this paper are three types such as high-variety and repetitive low-volume pattern, extremely-high-variety and nonrepetitive low-volume pattern, and high-variety and extremely-low-volume pattern. The short-run standardized control charts developed by extending the long-run ${\bar{x}}$-R, ${\bar{x}}$-s and I-MR charts have strengths for practioners to understand and use easily. Moreover, the short-range acceptance control charts developed in the study can be efficiently used through combining the functions of the inspection and control chart. The weighting schemes such as Shewhart, moving average (MA) and exponentially weighted moving average (EWMA) can be considered by the reliability of data sets. The two types according to the use of control chart are presented in the short-range standardized charts and acceptance control charts. Finally, process capability index(PCI) and process performance index(PPI) classified by the demand patterns are presented.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2010년도 춘계학술대회
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• pp.123-128
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• 2010

This article investigates economic-statistical design of VSI(variable samling interval) charts considering Various Runs Rules. Most recent adaptive control charts are conplex designs. Actually It's not easy to operating control quality process. We propose a procedure for designing VSI Runs charts, based on Lorenzen and Vence's model. The optimal design parameters of the charts can be determined by minimizing the cost model. And computational experiments show that the VSI Runs Rules charts is superior to the FSSI Runs Rules charts in the economic-statistical characterisitics.

• 한국멀티미디어학회논문지
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• 제3권6호
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• pp.661-673
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• 2000

본 논문에서는 분산 구조를 갖는 웹 기 반 HW/SW 통합설계 환경(WebCEDA)을 제안하고, HW/SW 통합설계 절차중에서 시스템 기술에 사용할 SpecCharts 기술 환경(ScSE)을 구현한다. WebCEDA는 기존의 통합설계 도구가 갖는 플랫폼 제한, 새로운 기술 추가의 어려움, 공동 작업 환경의 부재와 같은 단점을 해결할 수 있는 3층 클라이언트/서버 구조를 가진다. ScSE는 웹 인터페이스, SpecChars 에디터, HW/SW 통합설계응용 서버, SpecCharts 변환키로 구성된다. 다양한 예제를 SpecCharts 에디터사에서 기술하고, SpecCharts 변환기를 통해 CHDL로 변환시킨 후 Synopsys 상에서 시뮬레이션을 수행함으로써 구현된 ScSE가 정확하게 동작함을 확인하였다. 위의 실험 결과를 통해 ScSE는 시스템 기술의 복잡도 감소, 시스템 설계자의 자연스런 추상화된 설계 유도 등의 장점이 있음을 보였다.

• Journal of the Korean Data and Information Science Society
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• 제4권
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• pp.31-44
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• 1993

Multivariate exponentially weighted moving average (EWMA) control charts for monitoring the variance-covariance matrix are investigated. A variable sampling interval (VSI) feature is considered in these charts. Multivariate EWMA control charts for monitoring the variance-covariance matrix are compared on the basis of their average time to signal (ATS) performances. The numerical results show that multivariate VSI EWMA control charts are more efficient than corrsponding multivariate fixed sampling interval (FSI) EWMA control charts.

• 대한안전경영과학회지
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• 제6권4호
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• pp.195-213
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• 2004

This paper deals with an efficient and effective method on measuring, monitoring and evaluating safety and environmental performances of a process using SPC control charts. We propose 7 safety control charts as a tool to monitor hazard dendritics, and we propose 15 environment control charts to monitor pollution emissions. We also propose useful guidelines that SPC(Statistical Process Control) control charts can be used for safely and environmental monitoring.

• Journal of the Korean Data and Information Science Society
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• 제16권2호
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• pp.467-476
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• 2005

Multivariate control charts for monitoring mean vector of several related quality variables with combine-accumulate approach and accumulate-combine apprach were investigated. Shewhart chart is also proposed to compare the performances of CUSUM and EWMA charts. Numerical comparisons show that CUSUM and EWMA charts are more efficient than Shewhart chart for small or moderate shifts, and multivariate charts based on accumulate- combine approach is more efficient than corresponding multivariate charts based on combine-accumulate approach.

• 품질경영학회지
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• 제22권4호
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• pp.13-27
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• 1994

This study is concerned with design of EWMA control charts for counted data. Control charts for the fraction defective and the number of defects are designed. Performance analysis is accomplished for validity of the designed EWMA control charts. Average run length(ARL) is adopted as a criterion for comparison. Simulation results show that the designed EWMA control charts have shorter ARL than pn, p and c control charts when the fraction nonconforming or the average defect number are shifted. This means that the designed control charts can detect the out of -control state of the process more fastly than the traditional control charts.

• 품질경영학회지
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• 제30권2호
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• pp.99-117
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• 2002

Variable sampling interval(VSI) and variable sample size(VSS) control charts vary the sampling rate for the next sample depending on the current chart statistic. This paper develops EWMA charts with the VSI and VSS features, and investigates the effectiveness of these charts in context of an economic model. The economic properties of these charts are evaluated by using Markov chain methods. The model contains cost parameters which allow the specification of the costs associated with sampling, false alarms, and operating off target. This economic model can be used to quantify the cost saving that can be obtained by using control charts with the VSI and VSS features instead of with the fixed sampling rate(FSR) feature, and can also be used to gain insight into the way that control charts with the VSI and VSS features should be designed to achieve optimal economic performance. The economic performance of X charts with the VSI and VSS features is also considered.

• International Journal of Quality Innovation
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• 제3권2호
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• pp.46-56
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• 2002

The presence of imprecise measurement may seriously affect the efficiency of process control and production cost. A cost model is derived to determine the design parameters of the economic asymmetric $\bar{X}$ and S control charts including measurement errors. The effects of imprecise measurement on the performance of the economic asymmetric $\bar{X}$ and S control charts and production cost are examined for the case where the process mean and process standard deviation may change. Application of the proposed control charts is demonstrated through an example. Numerical examples illustrate the effects of imprecise measurement on the design parameters of the proposed control charts. It shows that the imprecision measurement may seriously affrct the ability of the proposed control charts to detect process disturbances quickly, change the sampling frequency, and increase the production cost compared to the control charts excluding measurement errors.

• 한국해양공학회지
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• 제17권1호
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• pp.61-66
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• 2003

A nautical chart is an essential material not only for the safety of navigation at sea, but also for the research and understanding of the ocean. Paper nautical harts have been used for navigational purposes for several hundreds years, but it was show that paper nautical charts have certain limitations, because the speed of ships has increased dramatically, and Global Positioning Systems (GPS) are now available at sea. Thus, the development of digital charts has been conducted by a number of countries. As a result, the International Hydrographic Organization (IHO) has developed a standard format, Special Publication No. 57 (S-57), as a guideline for the production of electronic navigational charts (ENC). Even though ENCs are a state-of-the-art navigational tool because they are produced on the basis of Geographical Information System (GIS) technology, they can be utilized for various purposes. in this paper, the usage of paper nautical charts, ENCs, and digital charts is reviewed. Also, the various application system that make use of electronic navigational harts and digital charts, as a basic geographical source of information, will be examined on the basis of GIS.