• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1838-1842
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• 2004

Gain and phase margins of a first order plus delayed time (FOPDT) process controlled by generalized predictive controller (GPC) are related to the control parameters ${\lambda}$ (control move suppression parameter) and ${\alpha}$ (smoothing filter coefficient) and the normalized delay of the process. Variation ranges of gain and phase margins are determined. It is shown that the margins cannot be assigned independently for a wide range of variation and the range is narrowing by increase of the normalized delay of the process. And finally curves are given to use for adjustment of the controller parameters in order to obtain a specific pair of gain and phase margins.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.1
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• pp.98-107
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• 2004

Proper finishing/polishing of dental restorations are critical clinical procedures that enhance both esthetics and longevity of restored teeth. This study was to compare the effects of immediate and delayed finishing/polishing procedures on the surface roughness and surface hardness of tooth-colored restoratives including two microfilled composite resins, such as Filtek A110 and Silux Plus, two hybrid composite resins, such as Revolution formular2 and Palfique Estelite. A total of 48 specimens were made for each material. The first 16 specimens served as the control group and the remaining 32 specimens were randomly divided into two equal groups. The control group was stored in distilled water at $37^{\circ}C$ for 1 week after light polymerization against the Mylar sheet. The first experimental group was finished/polished immediately after light polymerization and stored for 1 week in distilled water at $37^{\circ}C$, whereas the while the second group was finished/polished 1 week after light polymerization and stored in distilled water at $37^{\circ}C$. The results were as follows: 1. The smoothest surface was produced by Mylar sheet and finishing/polishing procedure increased the surface roughness. However, the surface roughness of composite resins were not influenced by the finishing/polishing timing. 2. There were significant differences about surface roughness between Revolution formular 2 and Silux Plus, regarding immediate finishing/polishing, and between Palfique Estelite and Silux Plus regarding delayed finishing/polishing(p<0.05). 3. The sequence of the surface hardness was ascending order by Revolution formular 2, Silux Plus, Filtek A110 and Palfique Estelite. However there were no significant differences about hardness among the control group and two finishing/polishing timing groups. 4. The effects of finishing/polishing time on surface roughness and hardness appeared to be material-dependent.