• Journal of Korean Society for Quality Management
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• v.26 no.1
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• pp.108-125
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• 1998

The EWMA(Exponentially Weighted Moving Average) has recently received a great deal of attention in the quality control literature as a process monitoring tool on the shop floor of manufacturing industires, since it is easy to plot, to interpret, and its control limits are easy to obtain. Most a, pp.ications of the EWMA for process monitoring have concentrated on the problem of detecting shifts of a process mean and a process standard deviation with ARL(Average Run Length) properties. But there may be the necessity of controlling linearity on product quality such as the correlation coefficient to the process operator. Control managers may want to protect the increase of a process correlation coefficient value, such as 0, between two variables of interest. However, there are few studies concerned on this part. Therefore, we propose EWMA models for a process correlation coefficient using two transformed statistics, T-statistic and (Fisher's) Z-statistic. We also present some results of simulation by SAS/IML and compare two models.

• 한국가스학회:학술대회논문집
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• 2000.09a
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• pp.215-220
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• 2000

• School Mathematics
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• v.4 no.2
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• pp.147-160
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• 2002

The purpose of this study is to examine the The correlation between information processing types and mathematical communication abilities / word problem solving abilities. The results obtained are as follows: 1 Simultaneous/continuous information process types showed statistically high correlation with mathematical communication abilities. However, the correlation between simultaneous information process and mathematical communication abilities is a little higher than the correlation between continuous information process and mathematical communication abilities. 2. There is a high correlation between mathematical communication abilities and word problem solving abilities. Especially, speaking ability is much more correlated with four factors of word problem solving than reading, writing and listening, Through this study, we can conclude that information process types should be consider ed in order to improve mathematical communication abilities and mathematical communication abilities is essential in word problem solving.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.83-91
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• 1996

We first obtain the departure process of a D-BMAP/Geo/1/K queue. The departure process is then exactly characterized by a k-state MMBP in order to capture the burstiness and correlation of the departure process.

• Journal of The Korean Association For Science Education
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• v.25 no.5
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• pp.624-633
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• 2005

Line graphs are frequently used to communicate data and basic concepts in classroom activities, Science teachers often assume that students are able to interpret the symbolic meaning of the graphs, but such an assumption is not based on sufficient evidence, The purpose of this study was to investigate the relationships of graphing ability to science-process skills and academic achievement of high school students: With regard to science-process skills, graphing ability was found to have a slight correlation with science-process skills (.41). Among the sub-skills of the science-process, graphing ability was seen to have a relatively high correlation with basic science-process skills such as 'measuring', 'inferring', 'predicting', while having relatively low correlation with integrated science-process skills such as 'formulating hypothesis' and 'generalization', With regard to academic achievement, graphing ability appeared to have no correlation with academic achievement (.06). Hence, a correlation between graphing ability and science-process skills was proved. It can also be concluded that improving graphing ability will greatly support students with their science study and, therefore, organized efforts and efficient educational methods should be developed in order to overcome the insufficient graphing ability among high school students.

• Journal of Communications and Networks
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• v.2 no.1
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• pp.58-68
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• 2000

In this paper we introduce the correlation-aided distributed sample acquisition (CDSA) scheme for fast cell search in IMT-2000 W-CDMA cellular system. The proposed scheme incorporates the state symbol correlation process into the comparison-correction based synchronization process of the original DSA scheme to enable fast acquisition even under very poor channel environment. for its realization, each mobile station (MS) has to store in its memory a set of state sample sequences. which are determined by the long-period scrambling sequences used in the system and the sampling interval of the state samples. CDSA based cell search is carried out in two stages : First, the MS first acquires the slot timing by using the primary synch code (PSC) and then identifies the igniter code which conveys the state samples of the current cell . Secondly. the MS identifies the scrambling code and frame timing by taking the comparison-correction based synchronization approach and, if the identification is not done satisfactorily within preset time. it initiates the state symbol correlation process which correlates the received symbol sequence with the pre-stored state sample sequences for a successful identification. As the state symbol SNR is relatively high. the state symbol correlation process enables reliable synchronization even in very low chip-SNR environment. Simulation results show that the proposed CDSA scheme outperforms the 3GPP 3-step approach, requiring the signal power of about 7 dB less for achieving the same acquisition time performance in low-SNR environments. Furthermore, it turns out very robust in the typical synchronization environment where large frequency offset exists.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.6
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• pp.579-587
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• 2015

Semiconductor manufacturing industry is a high density integration industry because it generates a vest number of data that takes about 300~400 processes that is supervised by numerous production parameters. It is asked of engineers to understand the correlation between different stages of the manufacturing process which is crucial in reducing production costs. With complex manufacturing processes, and defect processing time being the main cause. In the past, it was possible to grasp the corelation among manufacturing process stages through the engineer's domain knowledge. However, It is impossible to understand the corelation among manufacturing processes nowadays due to high density integration in current semiconductor manufacturing. in this paper we propose a canonical correlation analysis (CCA) using both wafer test voltage variables and fail bit counts variables. using the method we suggested, we can increase the semiconductor yield which is the result of the package test.

• Fibers and Polymers
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• v.3 no.2
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• pp.80-84
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• 2002

Tension control is an important factor in producing high quality knitted products and in maintaining good processing condition. Yarn tension during knitting is subject to be affected from many elements of the machine and process parameters. Several factors including yam feeding speed, feeding angle, and needle gauge that are considered to influence on the tension variation were investigated. Yam feeding speed did not show high contribution to the tension variation but feeding angle of yam did show high correlation with the tension. No or negative correlation of the tension with needle gauge was found from the results. In order to keep well-determined process condition in the knitting manufacturing, it is strongly suggested that all knitting elements and parameters should be in the integrated control circumstance.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.12 no.1
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• pp.57-70
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• 2017

Objectives : The purpose of this study is to find out the factors affecting the cervical angle with kyphosis. Methods : We investigated 340 cases of patients who had cervical kyphosis. We used cervical angle, flexion malposition angle, odontoid process cline angle, axis-atlas cline angle, odontoid process-atlas cline angle and occiput-atlas cline angle. Correlations between cervical angle and flexion malposition angle, odontoid process cline angle, axis-atlas cline angle, odontoid process-atlas cline angle, occiput-atlas cline angle were analyzed by pearson correlation analysis. Results : The correlation between cervical angle and flexion malposition angle was p-value 0.007, and odontoid process cline angle was p-value 0.002, and axis-atlas cline angle was p-value 0.000, and odontoid process-atlas cline angle was p-value 0.000, and occiput-atlas cline angle was p-value 0.012. Conclusions : Flexion malposition angle, odontoid process cline angle are inversely proportional to cervical angle. And correlation is statistically significant(p<0.01). Axis-atlas cline angle, odontoid process-atlas cline angle are proportional to cervical angle. And correlation is statistically significant(p<0.01). Occiput-atlas cline angle is proportional to cervical angle. And correlation is statistically significant(p<0.05).

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.2
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• pp.27-34
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• 2014

In this paper, we investigate the statistical correlation of the time series for temperature measured at the heat box in the automobile drying process. We show, in terms of the sample variance, that a significant non-linear correlation exists in the time series that consist of absolute temperature changes. To investigate further the non-linear correlation, we utilize the volatility, an important concept in the financial market, and induce volatility time series from absolute temperature changes. We analyze the time series of volatilities in terms of the de-trended fluctuation analysis (DFA), a method especially suitable for testing the long-range correlation of non-stationary data, from the correlation perspective. We uncover that the volatility exhibits a long-range correlation regardless of the window size. We also analyze the cross correlation between two (inlet and outlet) volatility time series to characterize any correlation between the two, and disclose the dependence of the correlation strength on the time lag. These results can contribute as important factors to the modeling of forecasting and management of the heat box's temperature.