When the production run is short and process parameters change 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, however, is not sensitive at small shifts in the magnitude of CV. This study suggest the CV-GWMA(generally weighted moving average) control chart, combining the GWMA technique, which shows better performance than the EWMA(exponentially weighted moving average) or DEWMA(double exponentially weighted moving average) technique in detecting small shifts of the process. Through a performance evaluation, the proposed control chart showed more excellent performance than the existing CV-EWMA control chart or the CV-DEWMA control chart in detecting small shifts in CV.

A classical Demerit control chart is used to monitor the process through which various types of defects in complex products, such as automobiles, computers, mobile phones, etc. are found in general. As a technique for rapidly detecting small shifts of the process mean in the control chart, the EWMA(exponentially weighted moving average) technique is very effective. This study suggested the Demerit-GWMA control chart, combining the GWMA(generally weighted moving average) technique, which shows better performance than EWMA technique in detecting small shifts of process mean, into the classical Demerit control chart, and evaluated its performance. Through the evaluation of its performance, it was found that the Demerit-GWMA control chart is more sensitive than both the classical Demerit control chart and the Demerit-EWMA control chart in detecting small shifts of process mean.

Background:Dexmedetomidine is known to be administered for sedation safely even in a very elderly patient. The purpose of this study was to determine the effect of age on clinically optimal dose of dexmedetomidine for sedation. Methods: We enrolled 50 patients ASA class I and II, scheduled for lower extremity surgery that need. They were classified into a young group (n = 26), aged below 75 and an old group (n = 24), aged above 75. Dexmedetomidine was continuously infused 0.5 μg/kg within 10 min, followed by maintenance at a dose of 0.5 μg/kg/min, initially. The next dose was selected using the Dixon's up-and-down method. Results: The cED50 of dexmedetomidine required to maintain optimal sedation level in young and old group were 0.50 and 0.48 μg/kg, respectively. With isotonic regression, cED95 of dexmedetomidine was 0.71 μg/kg (95% confidence intervals 0.57-1.06 μg/kg) and 0.58 μg/kg (95% confidence intervals 0.51-0.67 μg/kg). There were no significant differences in cED50 (P = 0.21), recovery variables, or incidence of side effects between the two groups. Conclusions: Clinically optimal dose of dexmedetomidine was not affected to the age during sedation.

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