• 해양환경안전학회지
• /
• 제17권2호
• /
• pp.137-142
• /
• 2011

지난 60년간 급속한 항만 개발로 인하여 다량의 해도가 여러 종류의 축척 및 구역으로 제작되어 인접구역이 효과적으로 연결되지 못하거나 과도한 중첩 구역이 발생하는 경우가 있으며 무리한 제분도의 사용으로 이용자에게 혼란 및 불편을 야기하고 있는 실정이다. 이 연구의 목적은 대한민국에서 간행되는 해도의 구역 및 축척별 분석을 통하여 새로운 해도구역 조정안을 제시하는데 있으며 이를 통해 항해 편의를 제공하는데 있다. 합리적인 해도구역 조정을 위하여 연구진이 전문가 의견법을 통하여 개정안을 마련한 후 이용자를 대상으로 한 설문조사 및 도선구역별 도선사 협회의 의견 수렴 등을 통하여 그 타당성을 검증받고 의견을 수렴하여 보완하였다. 연구의 결과로 현재 간행되고 있는 309장의 해도는 334장으로 변경되었다.

• 품질경영학회지
• /
• 제40권3호
• /
• pp.327-336
• /
• 2012

Purpose: In this study, we research the hurdle rate method to suggest the robust control chart for a contaminated process less vulnerable to fault values than existing control charts. Methods: We produce the results of p, ARL values to compare the performance of two control charts, $\bar{x}-s$ that has been used typically and TM-TS that is suggested by this paper. We implement the simulation focusing on three cases, change of deviation, mean and both of them. Results: We draw a conclusion that the TM-TS control chart has better efficiency than $\bar{x}-s$ control chart over the three cases. Conclusion: We insist that applying TM-TS control chart for a polluted process is more effective than $\bar{x}-s$ control chart.

• 대한한의진단학회지
• /
• 제14권2호
• /
• pp.51-66
• /
• 2010

Objectives: In this study, diagnosis of an ontology-based electronic chart system works by presenting a model electronic chart system is contributing to the standardization and objectification in Oriental Medicine field. Methods: The clinic is currently used in the electronic chart, and use surveys and research utilization was diagnosed. In addition, the symptoms with medicines, prescriptions, patterns ontology data, information, relationships between the association was derived. electronic chart the flow of information from the input data stream was defined using the ontology. Medicines, prescriptions, patterns diagnosis ontology, using the process model presented in the electronic chart. Results: This study show that interoperable model within the diagnostic capabilities of the electronic chart system in Oriental Medicine and represent diagnosis process in the system with symptoms. Conclusions: Diagnosed with symptoms of ontology integration with electronic chart to study the model was placed goal. Diagnosis and prescription due to strong associative connection implies an ontology can be seen even more important. Diagnostic elements will be added to enhance the diagnostic capabilities in the electronic chart can be varied and objective diagnostic model can be presented. This study extends the range for the CDSS, and new areas of research can be presented.

• 한국경영과학회지
• /
• 제39권1호
• /
• pp.1-12
• /
• 2014

This article proposes a variable sampling interval (VSI) $\bar{X}$ control chart using weighted standard deviation (WSD) method for skewed populations. The WSD method decomposes the standard deviation of a quality characteristic into upper and lower deviations and adjusts control limits and warning limits of a control chart in accordance with the direction and degree of skewness. A control chart constant is derived for estimating the standard deviation of skewed distributions with the mean of sample standard deviations. The proposed chart is compared with the conventional VSI $\bar{X}$ control chart under some skewed distributions. Simulation study shows that the proposed WSD VSI chart can control the in-control average time to signal (ATS) as an adequate level better than the conventional VSI chart, and the proposed chart can detect a decrease in the process mean of a quality characteristic following a positively skewed distribution more quickly than the standard VSI chart.

• 대한산업공학회지
• /
• 제34권3호
• /
• pp.328-336
• /
• 2008

This research proposes a method for economic-statistical design of adaptive moving average (A-MA) charts. The basic idea of the A-MA chart is to accumulate previous samples selectively in order to increase the sensitivity. The A-MA chart is a kind of adaptive chart such as the variable sampling size (VSS) chart. A major advantage of the A-MA chart over the VSS chart is that it is easy to maintain rational subgroups by using the fixed sampling size. A steady state cost rate function is constructed based on Lorenzen and Vance (1986) model. The cost rate function is optimized with respect to five design parameters. Computational experiments show that the A-MA chart is superior to the VSS chart as well as to the Shewhart $\bar{X}$ chart in the economic-statistical sense.

• 산업경영시스템학회지
• /
• 제39권1호
• /
• pp.116-122
• /
• 2016

Recently, the production cycle in manufacturing process has been getting shorter and different types of product have been produced in the same process line. In this case, the control chart using coefficient of variation would be applicable to the process. The theory that random variables are located in the three times distance of the deviation from mean value is applicable to the control chart that monitor the process in the manufacturing line, when the data of process are changed by the type of normal distribution. It is possible to apply to the control chart of coefficient of variation too. ${\bar{x}}$, s estimates that taken in the coefficient of variation have just used all of the data, but the upper control limit, center line and lower control limit have been settled by the effect of abnormal values, so this control chart could be in trouble of detection ability of the assignable value. The purpose of this study was to present the robust control chart than coefficient of variation control chart in the normal process. To perform this research, the location parameter, ${\bar{x_{\alpha}}}$, $s_{\alpha}$ were used. The robust control chart was named Tim-CV control chart. The result of simulation were summarized as follows; First, P values, the probability to get away from control limit, in Trim-CV control chart were larger than CV control chart in the normal process. Second, ARL values, average run length, in Trim-CV control chart were smaller than CV control chart in the normal process. Particularly, the difference of performance of two control charts was so sure when the change of the process was getting to bigger. Therefore, the Trim-CV control chart proposed in this paper would be more efficient tool than CV control chart in small quantity batch production.

• 산업경영시스템학회지
• /
• 제31권4호
• /
• pp.114-120
• /
• 2008

The control chart is widely used statistical process control(SPC) tool that searches for assignable cause of variation and detects any change of process. Generally, ${\bar{X}}-R$ control chart and ${\bar{X}}-S$ are most frequently used. When the production run is short and process parameter changes frequently, it is difficult to monitor the process using traditional control charts. In such a case, the coefficient of variation (CV) is very useful for monitoring the process variability. The CV control chart is an effective tool to control the mean and variability of process simultaneously. The CV control chart, however, is not sensitive at small shift in the magnitude of CV. In this paper, we propose an CV-EWMA (exponentially weighted moving average) control chart which is effective in detecting a small shift of CV. Since the CV-EWMA control chart scheme can be viewed as a weighted average of all past and current CV values, it is very sensitive to small change of mean and variability of the process. We suggest the values of design parameters and show the results of the performance study of CV-EWMA control chart by the use of average run length (ARL). When we compared the performance of CV-EWMA control chart with that of the CV control chart, we found that the CV-EWMA control chart gives longer in-control ARL and much shorter out-of-control ARL.

• 한국품질경영학회:학술대회논문집
• /
• 한국품질경영학회 2007년도 춘계학술대회
• /
• pp.287-296
• /
• 2007

Pearn et al.(2002) supposed the $C_{pp}$ multiple process performance analysis chart. This chart display 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. With bootstrapping method, we can display the distribution of the process variation and process departure on the $C_{pp}$ multiple process performance analysis chart.

• 한국품질경영학회:학술대회논문집
• /
• 한국품질경영학회 2006년도 추계 학술대회
• /
• pp.195-198
• /
• 2006

In this paper, we propose a 2dimension Control Chart. Suggested which Control chart augments Schwart Control chart which is 1-dimensional and Independent variable and dependent variable interrelationship by using control chart. Schwart control chart cannot use input variable and output variable together. In this paper, we try to analysis input variable and output variable dependent and effect. So called 2-dimensional control char.

• Industrial Engineering and Management Systems
• /
• 제16권1호
• /
• pp.109-117
• /
• 2017

In this article, a control chart based on multiple dependent (or deferred) state sampling for the gamma distributed quality characteristic is proposed using the gamma to normal transformation. The proposed control chart has two pairs of control limits, which can be determined by considering the in-control average run length (ARL). The shift in the scale parameter of a gamma distribution is considered and the out-of-control ARL is evaluated. The performance of the proposed chart has been shown for different levels of the parameters of the proposed control chart. It is also shown that the proposed chart is better than the Shewhart chart in terms of ARLs. A case study with a real data has been included for the practical usage of the proposed scheme.