• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.929-934
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• 2004

As 3D scanner develops, it can be used in measurement. To accomplish complete 3D measurement, the scanner has to view different sides of the target. It can be done by moving the scanner and fix it at every measuring point. By human, it would take so much time. However, by using robot, measuring time can be reduced and the procedure can be automated. It is suitable for 6R serial manipulator to do this kind of work in which the scanner should go any position in arbitrary orientation. We did inverse kinematics analysis by analytical and graphical methods. Then, we compared two methods.

• The korean journal of orthodontics
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• v.46 no.1
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• pp.3-12
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• 2016

Objective: The purpose of this study was to compare the precision of three-dimensional (3D) images acquired using iTero$^{(R)}$(Align Technology Inc., San Jose, CA, USA) and Trios$^{(R)}$(3Shape Dental Systems, Copenhagen, Denmark) digital intraoral scanners, and to evaluate the effects of the severity of tooth irregularities and scanning sequence on precision. Methods: Dental arch models were fabricated with differing degrees of tooth irregularity and divided into 2 groups based on scanning sequence. To assess their precision, images were superimposed and an optimized superimposition algorithm was employed to measure any 3D deviation. The t-test, paired t-test, and one-way ANOVA were performed (p < 0.05) for statistical analysis. Results: The iTero$^{(R)}$ and Trios$^{(R)}$ systems showed no statistically significant difference in precision among models with differing degrees of tooth irregularity. However, there were statistically significant differences in the precision of the 2 scanners when the starting points of scanning were different. The iTero$^{(R)}$ scanner (mean deviation, $29.84{\pm}12.08{\mu}m$) proved to be less precise than the Trios$^{(R)}$ scanner ($22.17{\pm}4.47{\mu}m$). Conclusions: The precision of 3D images differed according to the degree of tooth irregularity, scanning sequence, and scanner type. However, from a clinical standpoint, both scanners were highly accurate regardless of the degree of tooth irregularity.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.836-839
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• 2004

Qualitative elevation of products is very important Part. A business racking us brains to find for qualitative elevation of products. Recently, measurement accuracy of a non-contact 3D scanner has been rapidly improving. As a result, the number application cases of non-contact 3D scanners are increasing. A non-contact 3D scanner is capable of measuring a curved surface rapidly and has high resolution. It is more affordable and potable than the CMMs, It is therefore expected to be applied more frequently in more diverse industries. Automating the measuring process using a non-contact 3D scanner and developing a technology, which allows a user to measure easily, will eventually improve the quality of products. As their inspection and analysis processes improve.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1205-1206
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.855-856
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.501-502
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.391-392
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.795-796
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.843-846
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• 1994

The bucking and postbuckling behavior of composite laminated long cylinders under lateral pressure are investigated by the nonlinear finite element method. A long cylinder of 3-D shell problem is modelled as 2-D plane strain problem for analysis. And for the finite element analysis, eight nodes quadratic element is utilized. Arc-length method is adopted for the iteration and load-increment along postbuckling equilibrium path. The composite laminated cylinders in study are composed of cross-plied uniaxially reinforced shells. As a prsult, buckling load and postbuckling behavior are discussed.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.170-176
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• 2005

Analysis of structures which are composed of numerous repeated unit structures can be simplified by using homogenized properties. If the unit structure is repeated in one direction, the whole structure may be regarded as a beam. Once the effective stiffness is obtained from the analysis of the unit structure in a proper way, the effort for the detail modeling of the global structure is not required, and the real structure can be replaced simply with a beam. This study proposes a kinematical periodicity constraint to be imposed on the FE model of the unit structure, which improves the accuracy of the effective stiffness. The method is employed to a one dimensionally arrayed 3D structure containing periodically repeated un-symmetric holes. It is demonstrated that the deformation behavior of the homogenized beam agrees well with that of the real structure.