• 대한치과보철학회:학술대회논문집
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• 1999.04a
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• pp.81.1-81.1
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• 1999

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.13.1-13.12
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• 2016

Background: Mandibular motion tracking system (ManMoS) has been developed for orthognathic surgery. This article aimed to introduce the ManMoS and to examine the accuracy of this system. Methods: Skeletal and dental models are reconstructed in a virtual space from the DICOM data of three-dimensional computed tomography (3D-CT) recording and the STL data of 3D scanning, respectively. The ManMoS uniquely integrates the virtual dento-skeletal model with the real motion of the dental cast mounted on the simulator, using the reference splint. Positional change of the dental cast is tracked by using the 3D motion tracking equipment and reflects on the jaw position of the virtual model in real time, generating the mixed-reality surgical simulation. ManMoS was applied for two clinical cases having a facial asymmetry. In order to assess the accuracy of the ManMoS, the positional change of the lower dental arch was compared between the virtual and real models. Results: With the measurement data of the real lower dental cast as a reference, measurement error for the whole simulation system was less than 0.32 mm. In ManMoS, the skeletal and dental asymmetries were adequately diagnosed in three dimensions. Jaw repositioning was simulated with priority given to the skeletal correction rather than the occlusal correction. In two cases, facial asymmetry was successfully improved while a normal occlusal relationship was reconstructed. Positional change measured in the virtual model did not differ significantly from that in the real model. Conclusions: It was suggested that the accuracy of the ManMoS was good enough for a clinical use. This surgical simulation system appears to meet clinical demands well and is an important facilitator of communication between orthodontists and surgeons.

• The Journal of Advanced Prosthodontics
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• v.15 no.1
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• pp.11-21
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• 2023

PURPOSE. To compare the sagittal condylar inclination (SCI) in dentate individuals measured by the different methods with mechanical articulator (MA), virtual articulator (VA), and a jaw tracking device (JTD) system. MATERIALS AND METHODS. A total of 22 healthy dentate participants were enrolled in this study. For MA workflow, the SCI was obtained by a semi-adjustable articulator with protrusive interocclusal records. The SCI was also set on a VA by aligning intraoral scan (IOS) with cone beam computed tomography (CBCT) and facial scan (FS), respectively. These virtual workflows were conducted in a dental design software, namely VAI_OS-CBCT and VAI_OS-FS. Meanwhile, a JTD system was also utilized to perform the measurement. Intraclass correlation was used to assess the repeatability within workflows. The bilateral SCI values were compared by Wilcoxon matched-pairs signed rank test for each workflow, and Kruskal-Wallis test and post hoc p-value Bonferroni correction were used to compare the differences among four workflows. The agreement of VAI_OS-CBCT, VAI_OS-FS, and JTD compared with MA was evaluated by Bland-Altman analysis. RESULTS. Intraclass correlation of the SCI revealed a high degree of repeatability for each workflow. There were no significant differences between the left and right sides (P > .05), except for VAI_OS-CBCT (P = .028). Significant differences were not found between MA and VAI_OS-FS (P > .05). Bland-Altman plots indicated VAI_OS-CBCT, VAI_OS-FS, and JTD were considered to substitute MA with high 95% limits of agreement. CONCLUSION. The workflow of VAI_OS-FS provided an alternative approach to measure the SCI compared with MA.

• The Journal of the Korean dental association
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• v.58 no.11
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• pp.700-712
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• 2020

The conventional mouthguard fabrication process consists of elastomeric impression taking and followed gypsum model making is now into intraoral scanning and direct mouthguard 3D printing with an additive manufacturing process. Also, dental professionals can get various diagnostic data collection such as facial scans, cone-beam CT, jaw motion tracking, and intraoral scan data to superimpose them for making virtual patient datasets. To print mouthguards, dental CAD software allows dental professionals to design mouthguards with ease. This article shows how to make 3D printed mouthguard step by step.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.2
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• pp.109-114
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• 2008

In this paper, a dynamic learning controller for robot manipulator is implemented using real-time operating system with capabilities of multitasking, intertask communication and synchronization, event-driven, priority-driven scheduling, real-time clock control, etc. The controller hardware system with VME bus and related devices is developed and applied to implement a dynamic learning control scheme for robot manipulator. Real-time performance of the proposed dynamic learning controller is tested and evaluated for tracking of the desired trajectory and compared with the conventional servo controller.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.44.3-44.3
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• 2020

Sunspot substructure is an important subject to explain their stability and energy transport. Previous studies suggested two substructure models, monolithic and spaghetti model, but no clear evidence has been found supporting a particular model. To obtain the clue of the sunspot substructure the IRIS Mg II 2796Å slit-jaw images (SJI) were examined. The Mg II images formed in the chromosphere show bright patches inside umbrae which are regarded as an observational signature of upward propagating slow magnetohydrodynamic (MHD) waves. The slow MHD waves are expected to be generated by convective motion below the photosphere. By tracking the motion of the bright patches it is possible to estimate the locations of oscillation centers that correspond to the occurrence position of the convections. I investigated the spatial distribution of the oscillation center in a merging sunspot and found it is randomly distributed. It implies that the occurrence rate of the convective motion inside the sunspot is not much different from that of between the two sunspots, and supports the spaghetti model as the sunspot substructure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.15-22
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• 2002

This paper introduces a compensating system for machining error, which is resulted from chucking with separated jaws. In machining the chucked cylindrical workpiece, the deterioration of machining accuracy, such as out-of-roundness is inevitable due to the variation of the radial compliance of the chuck workpiece system which is caused by the position of jaws with respect to the direction of the applied force. To compensate the chucking compliance induced error, firstly roundness profile of workpiece due to chucking compliance after machining needs to be predicted. Then using this predicted profile, the compensated tool feed trajectory can be generated. And by synchronizing the cutting tool feed system with workpiece rotation, the chucking compliance induced error can be compensated. To satisfy the condition that the cutting tool feed system must provide high speed and high position accuracy, brushless linear DC motor is used. In this study, firstly through the force-deflection experiment in workpiece chucked lathe, the variation of radial compliance of chuck workpiece system is obtained. Secondly using the mathematical equation and cutting experiment result, the predicted profile of workpiece and its compensation tool trajectory are generated. Thirdly the configuration of compensation system using linear motor is introduced, and to improve the system performance, PID controller is designed. Finally the tracking performance of system is examined by experiment. Through the real cutting experiment, roundness is significantly improved.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.4
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• pp.382-394
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• 2022

The treatment of patients with severe periodontitis should be proceeded step-bystep through an accurate diagnosis of each patients' individual tooth and with a strategic treatment plan. Implant-supported fixed prosthetic restoration has the advantage of high patient satisfaction and stable vertical dimension compared to the removable partial denture. However, multiple teeth defect areas lacking hard tissue may be disadvantageous in aesthetic failure and longer treatment time. In addition, it takes a certain period of time to manufacture and install a conventional fixed prosthesis, and during this process, the provisional prosthesis must satisfy the mechanical, biological, and aesthetic requirements of teeth. The purpose of this article is to describe the fabrication of implant-supported fixed prosthesis through a step-by-step approach in a partially edentulous patient.