• Journal of Korean Society for Quality Management
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• v.23 no.3
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• pp.33-44
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• 1995

This paper presents an automated visual inspection system for the electronic parts manufacturing process. In this system, a statistical process control (SPC) method is integrated into the automated inspection method on a real time base. It shows how the collected data can be analyzed with the SPC to provide process information. Also presented are studies of subpixel image processing technology to improve the accuracy of parts measurements, and the cumulative-sum (CUSUM) control chart for fraction defectives. An application of the developed system to connector manufacturing process as a part of computer integrated manufacturing (CIM) is presented.

• The Korean Journal of Applied Statistics
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• v.25 no.6
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• pp.977-985
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• 2012

Data quality and climate forecasting performance deteriorates because of long climate data contaminated by non-climatic factors such as the station relocation or new instrument replacement. For a trusted climate forecast, it is necessary to implement data quality control and test inhomogeneous data. Before the inhomogeneity test, a reference series was created by $d$ index to measure the temperature series relationship between the candidate and surrounding stations. In this study, a inhomogeneity test to each season and climatological station was performed on the daily mean temperatures, daily minimum temperatures and daily maximum temperatures. After comparing two inhomogeneity tests, the traditional and the adjusted SNHT method, we found the adjusted SNHT method was slightly superior to the traditional one.

• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3794-3803
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• 2000

In a Video-on-Demand system, admission control that is used to serve multimedia data efficiently has to be perfonned by an accurate grasp of the condition of surplus resources. Most of all. we need to adaptable admission control mechanism because the disk has irregular response time caused by external elements of disk, and also has high deviation of amount demanded. In previous admission control schemes, they determined whether a new user is granted or not through a theoretical value. Although they based on the measurement, they left much to be desired in dealing with the service state. Measurement ~based statistical admission control scheme, as we su~~ested in this research, perfonns 2 processes of off-line process and on-line process in real service environment. Through this processes, we can grasp the accurate resource state of system and adaptive!y detennine the admission according to circumstances. Therefore, it can guarantee both maximum resource utilization and QoS(Quality of Service). On performance evaluations, we show that the video server can utilize maximum resource utilization with QoS guarantee through precision of perfonnance by measurement and adaptable admission control according to the requested bandwidth.

• Journal of Ocean Engineering and Technology
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• v.13 no.2 s.32
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• pp.74-82
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• 1999

Nowadays, the crank shaft motor vehicle has become essential as the important component. The machining precision was asked for manufacturing the shaft. They could be unstable in the quality by the conventional are welding. Both in-process quailty control and high reliability of the weld are the major concerns in applying friction wlding to the economical and qualified mass-production. No reliable nondestructive monitoring method is avaliable at present to determine the real-time evaluation of automatic production quality control for bar-to-bar friction welding of the crank shaft of O.D 24mm for motor vehicle. This paper, so that, presents the experimental examinations and statistical quantitative analysis of the correlation between the cumulative counts of acoustic emission(AE) during plastic deformation periods of the welding and the tensile strength and other properties of the bar-to-bar welded joints of O.D. 24mm shaft as well as the various welding variables, as a new approach which attempts finally to develop real-time quality monitoring system for friction welding, resulting in practical possiblility of real-time quality control more than 100% joint efficiency showing good weld with no micro structural defects.

• Journal of Korean Clinical Nursing Research
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• v.14 no.1
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• pp.33-44
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• 2008

Purpose: This study was performed to determine the effects of foot reflexology on pain and quality of sleep in patients with terminal cancer. Method: Quai-experimental research design was used. The subjects of this study were consisted of 19 for experimental group and 18 for control group. Visualue Scale(VAS) was used as the measurement tool of pain in this study, Verra & Snyder-Halpern Sleep Scale(VSH) and Visual Analogue Scale(VAS) were used as the measurement tool of perceived quality of sleep. Data were analyzed using statistical methods such as frequency, percent, $x^2$-test, t-test using SPSS WIN 12.0 program. Results: The hypothesis 1 that the experimental group with reflexology has less degree of pain than the control group without reflexology was supported (t=5.41, p<.001). The hypothesis 2 that the experimental group with reflexology has higher degree of VSH Scale than the control group without reflexology was supported(t=2.37, p=.02). The hypothesis 3 that the experimental group with reflexology has the difference among the mean of sleep VAS Scale during the 12 measurement periods was not supported(F=1.63, p=.08), and no significant interactions between group and time. Conclusion: It is considered that reflexology is effective for reducing cancer pain and improving quality of sleep in patients with terminal cancer.

• Journal of Korean Society for Quality Management
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• v.35 no.2
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• pp.106-112
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• 2007

In statistical process control, it is assumed that the process data are independent. However, most of chemical processes such as semi-conduct processes do not satisfy the assumption because of presence of autocorrelation between process data. It causes abnormal out of control signal in the process control and misleading estimation in process capability. In this study, we adopted Shore's method to solve the problem and propose an optimal subgroup size to estimate the variance correctly for AR(1) processes. Especially, we focus on finding an actual subgroup size for small samples based on simulation study.

• Journal of Korean Society for Quality Management
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• v.33 no.3
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• pp.135-148
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• 2005

This paper considers a six sigma project for reducing the project costs through project risk management. The project follows a disciplined process of five phases: define, measure, analyze, improve, and control. A risk management process map is used to identify process input and output variables. Seven key process input variables are selected by using C&E diagram and X-Y matrix and finally four vital few input variables are selected by the related statistical analysis. The optimum alternatives of the vital few input variables are obtained by the method of PUGH matrix. The process is running on control plan and we obtained substantial project cost reductions in early stage of the control phase.

• Proceedings of the KWS Conference
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• 1997.10a
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• pp.229-233
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• 1997

The demand to increase productivity and quality, the shortage of skilled labour and the strict health and safety requirements have led to the development of the automated welding process to deal with many of the present problems of welded fabrication. To make effective use of the automated arc welding process, it is imperative that a mathematical model, which can be programmed easily and fed to the robot, should be developed. The objectives of the paper are to develop the mathematical equations (linear and curvilinear) for study of the relationship between process variables and bead geometry by employing a standard statistical package program, SAS and to choose the best model for automation of the $CO_2$ gas arc welding process. Mathematical models developed from experimental results can be employed to control the process variables in order to achieve the desired bead geometry based on weld quality criteria. Also these equations may prove useful and applicable for automatic control system and expert systems.

• Journal of Korean Society for Quality Management
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• v.35 no.1
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• pp.24-34
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• 2007

This paper investigates the average run length (ARL) of a selectively moving average (S-MA) control chart. The S-U chart is designed to detect shifts in the process mean. The basic idea of the S-MA chart is to accumulate previous samples selectively in order to increase the sensitivity. The ARL of the S-MA chart was shown to be monotone decreasing with respect to the decision length in a previous research [3]. This paper derives the steady-state ARL in a closed-form and shows that the monotone property is resulted from head-start assumption. The steady-state ARL is shown to be a sum of head-start ARL and an additional term. The statistical design procedure for the S-MA chart is revised according to this result. Sensitivity study shorts that the steady-state ARL performance is still better than the CUSUM chart or the Exponentially Weighted Moving Average (EWMA) chart.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.4
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• pp.633-644
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• 2010

Purpose : This study was to investigate vascular dementia elders's activities of daily living, quality of life index and to determine how much vascular dementia elders is influenced by the 12 weeks combined exercise program with aerobic training and resistance exercise. Methods : Thirty patients with vascular dementia over 65 in B geriatrics hospital were recruited this study. Activities of daily living were measured by I-ADL(instrumental-activities of daily living) and B-ADL(basic-Activities of daily living) and quality of life index was measured by GQOL-D(geriatric quality of life scaledementia). Statistical analysis was used repeated one-way ANOVA to test mean difference by using SPSS 12.0 for windows. Results : After comparing the activities of daily living of experimental group that of control group according to the period of exercise, there were statistically significant differences in I-ADL, B-ADL score test and GQOL-D index test of both experimental and control groups. There was also a significant difference in comparing the results of 12 weeks exercise of the groups. Conclusion : 12 weeks combined exercise program had a good influence on vascular dementia elders's activities of daily living and quality of life index.