• Restorative Dentistry and Endodontics
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• 제37권4호
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• pp.220-227
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• 2012

Objectives: The study was to compare the shaping ability of Reciproc (VDW) and WaveOne (Dentsply Maillefer) instruments compared with ProTaper, Profile and hand instrument during the preparation of simulated root canals. Materials and Methods: Five groups (n = 5) were established. Reciproc, WaveOne, ProTaper, Profile and K file (K-flexo file) were used to prepare the resin simulated canals. A series of preoperative and postoperative images were taken by a microscope and superimposed in 2 different layers. The amount of resin removed from both the inner and the outer sides of the canal was measured to the level of 10 mm from the apical tip, with a 1 mm increment. Results: The mean of resin removal from the inner canal wall was not different from the outer canal wall for Reciproc and WaveOne groups at apical third (1 - 3 mm level). There was no difference in the change of working length and maintenance of canal curvature. NiTi instruments are superior to stainless-steel K file in their shaping ability. Conclusions: Within the limitation of this present study, Reciproc and WaveOne instruments maintained the original canal curvature in curved canals better than ProTaper and Profile, which tend to transport towards the outer canal wall of the curve in the apical part of the canal.

• Restorative Dentistry and Endodontics
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• 제29권1호
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• pp.44-50
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• 2004

This study compared the shaping ability of nickel-titanium rotary files with different rake angle and radial land. The nickel-titanium files used in this study were Profile(Dentsply, Maillefer, Ballaigues, Switzerland), Hero 642(Micromega, Besancon, France) and K3 (SybronEndo, Glendora, Ca, USA) file. Resin blocks substituted for root canals. 36 resin blocks were divided into 3 groups with 12 canals each The time for canal preparation was recorded. The images of pre- and postoperative resin canal were scanned and those were superimposed Amounts of canal deviation, total canal widths, inner canal widths, and outer canal widths were measured at apical 1, 2 ,3, 4, 5, 6, and 7mm levels. The amount of canal deviation was the smallest in Profile group , and the time far canal preparation was the shortest in Hero 642 group. K3 group resulted in competent characteristics in both measurements. Positive rake angle seemed to result in fast shaping of root canal and radial land guide the instrument in center of the canals and around curvatures. Radial land also tended to reduce the sense of screwing into the root canal. The proper selection of the nickel-titanium fie based on the knowledge about file design is needed for the safer, simpler and faster root canal therapy.

• 대한치과의사협회지
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• 제47권7호
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• pp.444-454
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• 2009

The purpose of this study was to compare the shaping abilities of LightSpeed, ProTaper-Universal, and hybrid technique using S-series of ProTaper-Universal and LigthSpeed. The 72 simulated root canals of J-shape were used and classified as flowing 3 groups according to the instrumentation methods; Group P of 24 canal blocks were prepared with ProTaper-Universal, Group L was prepared with LightSpeed, and Group H was prepared with hybrid technique (initial shaping with ProTaper-Universal SI and S2 and apical shaping with LightSpeed from #25 to #50). A second-year resident of Endodontic department prepared the resin block canals to apical size #50 (F5 in Group P). The time lapses for instrumentation and the reduction of root canal curvature after shaping were measured. The pre- and post-instrumented root canals were scanned and superimposed to evaluate and calculate the increased canal width and apical centering ratio. The results were as followings: Group Land H showed significant less instrumentation time than Group P (p < 0.05). The ProTaper system showed greater reduction of root canal curvature and working length diminishment than other methods (p < 0.05). LightSpeed system showed best canal curvature preserving characteristics. The Group P had greater instrumented widths at all levels examined (p < 0.05). Group L and Group H showed lower centering ratio (ability to preserve the canal center; the lower ratio means the better canal center preservation) than Group P (p < 0.05). Group H had the lowest centering ratio at the 1 mm level.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2008년도 추계학술대회
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• pp.303-316
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• 2008

For the past 25 years, Korean semiconductor has experienced enormous growth to be the highest production country in the world. Semiconductor industry is very time sensitive and driven by technology and process, and requires 24-hour full operation. The environment includes many different types of equipment, utilities, different gases and toxic chemicals as well as high voltage electricity. We have performed a survey with 3-shift engineers and workers in one line. The content of the questionnaire was about the correlation between fatigue and performance shaping factor (work type and work ability), and as a result we were able to deduce the correlation, p-value and the pattern of scatter plot. The shape of the model was made of 4 blocks for fatigue, 5 blocks for work type and 5 blocks for work ability, i. e. 14 blocks in total. As a conclusion to this findings, there was a correlation between fatigue and work type and work ability specifically in semiconductor industry, and we need some effort to reduce this.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.54-56
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• 2006

To get the robust and reliable input command, we designed shaping function for target tracking system with commander's handle. Input signals of the commander's handle are generated by human operator. It is response of the human to reduce the error between target and gun. But, tracking error while operator aim a moving target manually gives poor system performance. Input noise, particularly, affects hit accuracy as the system performance. We proposed the design method of input command shaping to reduce the Input noise and to improve the operation ability and convenience. We performed the experiments with combat vehicle, example of Target Tracking System, to show the proposed method is efficient and practical.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.571-571
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• 2001

The purpose of obturating the prepared root canal can be simply stated as to eliminate all avenues of leakage from the oral cavity or the periradicular tissues into the root canal system and to seal within the system any irritants that cannot be fully removed during canal cleaning and shaping procedures. The ability to achieve three-dimensional obturation of the root canal system is primarily dependent on the quality of the canal cleaning and shaping and the skill of the clinician.(omitted)

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.573.2-573
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• 2001

The objective of this study was to compare the apical shaping ability of the ProFile .04 taper, Lightspeed and HERO 642 rotary instruments and to assess the combined effect of GT Rotary files to Lightspeed and HERO 642 instruments. Forty-eight resin simulated root canal blocks divided into 4 groups with 12 canals. Forty-eight blocks were prepared by one operator with GT Rotary files using a high torque handpiece at 300 rpm. Thirty-six blocks in the three experimental groups were prepared with ProFile 04 taper file, Lightspeed file, HERO 642 file.(omitted)

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.588.1-588
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• 2001

The purpose of this study was to compare the root canal shaping ability of four nickel-titanium rotary instruments. Forty eight simulated curved root canals were instrumented in plastic with the Crown-down technique using the $ProTaper^{TM}$ , the ProFile, the $GT^{TM}$, and the Quantec. Canals were instrumented until apical canal were up to size 30 by one operator. Each instrument was used only once and instrumentation time was measured.(omitted)

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
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• pp.554-554
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• 2003

I. Objectives This study was done to evaluate the shaping ability of ProFile and ProTaper, K-Flexofile during instrumentation in simulated resin canals with different angles of curvature. II. Materials and Methods Ninety simulated root canals with a curvature of 15, 30 and 45 degree (following Schneider's method) were made of epoxy resin ($EPOXICURE^{TM}$, BUEHLER, USA) for this study. The canal length of simulated root canals was adjusted to 18 mm. The beginning point of curvature was positioned at 10mm from the canal orifice.(omitted)

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.195-200
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• 2008

This paper presents motion control of the Inchworm composed of the piezoelectric actuators and mechanical elements. Piezoelectric actuator shows nonlinear response characteristics including hysteresis due to the ferroelectric characteristics. This paper proposes feedback control scheme to improve the ability of tracking response to complex input signal and suppress the phenomenon of hysteresis using the sliding mode control technique with the integrator. The sliding mode control system has the limit to minimize both the settle time and overshoot. For making up this limit, this paper also suggests input shaping technique suitable to the inchworm control system.