• Journal of the Korean Data and Information Science Society
• /
• 제26권6호
• /
• pp.1593-1600
• /
• 2015

A control chart is very useful in monitoring various production process. There are many situations in which the simultaneous control of two or more related quality variables is necessary. We construct bivariate Shewhart control charts based on the trace of the product of the estimated variance-covariance matrix and the inverse of the in-control matrix and investigate the properties of bivariate Shewart control charts with VSI procedure for monitoring covariance matrix in term of ATS (Average time to signal) and ANSW (Average number of switch) and probability of switch, ASI (Average sampling interval). Numerical results show that ATS is smaller than ARL. From examining the properties of switching in changing covariances and variances in ${\Sigma}$, ANSW values show that it does not switch frequently and does not matter to use VSI procedure.

• 한국의류산업학회지
• /
• 제11권6호
• /
• pp.918-924
• /
• 2009

As the population of overweight and obese children is rising rapidly around the world, there are many researches on purchasing and wearing children's clothing and optimal sizes, but researches on obese children are still inadequate. This study was carried out on 192 obese children over 75% in BMI. The purpose of the study was to set up the optimal interval of sizing system using the loss function which would be a guide for obese children for selecting ready to wear of suitable size. Introducing a loss function, which reflects how much the purchasing desire changes according to the difference, we formulate the problem and suggest a procedure to determine the optimal standard sizes minimizing the loss. These results were as follows ; In size chart of top's, 4 sizes had been determined by a loss function, had covered more than 91.1% of all subjects. In size chart of bottom's, 5 sizes had been determined by a loss function, had covered more than 87.0% of all subjects.

• Journal of the Korean Data and Information Science Society
• /
• 제26권1호
• /
• pp.261-269
• /
• 2015

Nowadays the application of change point analysis has been indispensable in a wide range of areas such as quality control, finance, environmetrics, medicine, geographics, and engineering. Identification of times where process changes would help minimize the consequences that might happen afterwards. The main objective of this paper is to compare the change-point detection capabilities of Bayesian estimate and maximum likelihood estimate. We applied Bayesian and maximum likelihood techniques to formulate change points having a step change and multiple number of change points in a Poisson rate. After a signal from c-chart and Poisson cumulative sum control charts have been detected, Monte Carlo simulation has been applied to investigate the performance of Bayesian and maximum likelihood estimation. Change point detection capacities of Bayesian and maximum likelihood estimation techniques have been investigated through simulation. It has been found that the Bayesian estimates outperforms standard control charts well specially when there exists a small to medium size of step change. Moreover, it performs convincingly well in comparison with the maximum like-lihood estimator and remains good choice specially in confidence interval statistical inference.

• 한국의류학회지
• /
• 제39권1호
• /
• pp.147-160
• /
• 2015

This study suggests a detailed apparel sizing system for brands that target elderly men between the ages of 60 to 79 by studying body type differences of the age group based on data from 'The $5^{th}$ Korean Anthropometric survey'. Compared to middle aged men, elderly men body measurements appear to be smaller except in the midriff area, such as the natural waist circumference, waist circumference (omphalion), waist depth and waist depth (omphalion). The size chart in the study was established according to the KS size chart system with a size jump of 5cm in height, 5cm and 3cm in chest circumference, 2cm in waist circumference (omphalion) and 2cm in hip circumference. A total of 8 sizes were established with heights between 160cm and 170cm and chest measurements between 85cm to 100cm for casual tops. For suit tops, a total of 11 sizes were established with heights between 160cm and 170cm and chest measurements between 88cm to 100cm. For bottoms, detailed sizes were suggested by dividing basic and reference areas with 13 sizes between 84cm to 94cm in the waist circumference (omphalion) and between 90cm to 98cm in the hip circumference.

• 대한약침학회지
• /
• 제23권1호
• /
• pp.25-29
• /
• 2020

Objectives: Heavy menstrual bleeding has a significant effect on women's daily life and health consequences for theirs. Attention to women's and girls' menstrual health is critical for their health. This study presents the results of a novel research on the effect of chamomile capsule on the amount of bleeding, and the duration and interval of menstrual cycles. Methods: The current study was a randomized, double-blind, clinical trial, which was carried out on 118 female students living in dorms of Guilan University of Medical Sciences. The participants were divided into two groups of 59, each receiving either chamomile capsule 250 mg or placebo three times a day, for an interval beginning from 7 days before the starting menstruation till the next onset. Higham chart is the pictorial blood loss assessment to determine the amount and duration of menstrual bleeding. Data were analyzed using SPSS version 20. Alpha was set at 0.05 for all analyses. Results: The average amount of bleeding in the chamomile group decreased after taking the capsule (p = 0.001). However, statistical tests did not show any significant difference in terms of duration and interval between two bleeding in both the experimental and control groups (p > 0.05). Conclusion: The present study showed that the chamomile capsule decreases the amount of menstrual bleeding and can be used as a therapeutic method. Conclusion:The present study showed that the chamomile capsule decreases the amount of menstrual bleeding and can be used as a therapeutic method.

• 한국의료질향상학회지
• /
• 제25권1호
• /
• pp.43-51
• /
• 2019

Purpose: The time lag between the decision to initiate continuous renal replacement therapy (CRRT) and its actual initiation remains a major barrier in our intensive care units. We developed a CRRT pop-up chart on EMR for managing CRRT machines. Methods: This study measured time interval between the decision to prepare the CRRT machine and the actual use of the machine before and after using a CRRT pop-up chart. This study conducted a questionnaire of the medical staff to assess the changes in the quality of CRRT preparation. Results: A total of 95 patients on CRRT is analyzed. The time to find an available CRRT machine is decreased by 24.6%. The time to move a CRRT machine to the patient's bedside is decreased by 55.8%. Medical surveys of 44 nurses gave the following results. 1) The time to apprehend machines for 1 to 3 minutes is improved from 29.5% to 81.8%, and the time to apprehend machines over 3 minutes is decreased from 70.5% to 18.2%. 2) The number (6-all) of known machine locations is improved from 22.7% to 63.4%. 3) Interruption of a nurse's work due to telephone calls asking for the possession of movable CRRT equipment also is improved. Scores of 1-4 are improved from 15.9% to 41%. Scores of 5-7 are reduced from 52% to 15.9%. Conclusions: CRRT pop-up chart is shortened the time lag of CRRT machine preparation, reduced the nurse's phone workload and helped to improve the quality of CRRT care.

• Journal of the Korean Data and Information Science Society
• /
• 제21권6호
• /
• pp.999-1008
• /
• 2010

공정을 모니터링 하기 위한 전통적인 관리도는 표본들 사이의 일정한 추출간격에서 일정한 수의 표본을 취하여 만들어 지는 고정추출율 관리도이다. 본 연구의 목표는 표준적인 고정추출율을 갖는 다변량 관리도에 비하여 성능이 우수한 가변추출간격을 갖는 다변량 관리도를 개발하는데 있다. 대부분의 다변량 관리도에 대한 연구는 공정의 평균벡터를 모니터링 하는데 초점이 맞추어져 있다. 그러나 본 논문에서는 공정의 평균벡터와 분산-공분산을 동시에 모니터링 하기 위한 다변량 관리도를 연구한다. 가변추출간격을 갖는 다변량 슈하르트 관리도에 대하여 연구 하고자 한다.

• 품질경영학회지
• /
• 제33권4호
• /
• pp.117-122
• /
• 2005

Variable sampling rate(VSR) scheme varies the sampling rate for the current sample depending on the previous value of the control statistic. In this paper, we propose EWMA control charts with variable parameter(VP) scheme, which allows both the sample rate(the sample size or the sampling interval) and the weight to vary. We investigate the effectiveness of the VP scheme relative to the fixed parameter(FP) scheme and the VSR scheme in EWMA control charts. It is shown that using the VP scheme gives some improvements to the ability in detecting small and moderate shifts in the process normal mean.

• 한국의류학회지
• /
• 제26권6호
• /
• pp.923-934
• /
• 2002

The aim of this study is to suggest a Sizing System which has following points:- 1. In order to satisfy children of diverse figure shapes, we developed sizing system for three different figure type. Figure types are categorized into slim, normal, fat type based on the Rohrer Index. 2. For each figure types, we developed size chart using height bust circumference and hip circumference as basic measurements. The size codes are presented as the height-bust circumference or height-hip circumference. The size interval of height is 5cm for all figure types, such as 120,125,130 ‥‥ we developed a size allocation program, which is helpful when a customer doesn't know exact measurement of some body dimension. If a customer input measurements as much as he/she hows, the program allocates the nearest. At the end of the study, the sizing interaction sites were developed to present the results of the study clear.

• 품질경영학회지
• /
• 제30권2호
• /
• pp.99-117
• /
• 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.